metrics: upgraded prometheus http client to 0.9.4 to address label conflict in Nomad 0.9.x reported in #5345

vendor/github.com/prometheus/client_golang/prometheus/build_info.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build go1.12
+
+package prometheus
+
+import "runtime/debug"
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go 1.12+.
+func readBuildInfo() (path, version, sum string) {
+	path, version, sum = "unknown", "unknown", "unknown"
+	if bi, ok := debug.ReadBuildInfo(); ok {
+		path = bi.Main.Path
+		version = bi.Main.Version
+		sum = bi.Main.Sum
+	}
+	return
+}

vendor/github.com/prometheus/client_golang/prometheus/build_info_pre_1.12.go

@@ -0,0 +1,22 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !go1.12
+
+package prometheus
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go versions before
+// 1.12. Remove this whole file once the minimum supported Go version is 1.12.
+func readBuildInfo() (path, version, sum string) {
+	return "unknown", "unknown", "unknown"
+}

vendor/github.com/prometheus/client_golang/prometheus/collector.go

@@ -29,27 +29,72 @@ type Collector interface {
 	// collected by this Collector to the provided channel and returns once
 	// the last descriptor has been sent. The sent descriptors fulfill the
 	// consistency and uniqueness requirements described in the Desc
-	// documentation. (It is valid if one and the same Collector sends
-	// duplicate descriptors. Those duplicates are simply ignored. However,
-	// two different Collectors must not send duplicate descriptors.) This
-	// method idempotently sends the same descriptors throughout the
-	// lifetime of the Collector. If a Collector encounters an error while
-	// executing this method, it must send an invalid descriptor (created
-	// with NewInvalidDesc) to signal the error to the registry.
+	// documentation.
+	//
+	// It is valid if one and the same Collector sends duplicate
+	// descriptors. Those duplicates are simply ignored. However, two
+	// different Collectors must not send duplicate descriptors.
+	//
+	// Sending no descriptor at all marks the Collector as “unchecked”,
+	// i.e. no checks will be performed at registration time, and the
+	// Collector may yield any Metric it sees fit in its Collect method.
+	//
+	// This method idempotently sends the same descriptors throughout the
+	// lifetime of the Collector. It may be called concurrently and
+	// therefore must be implemented in a concurrency safe way.
+	//
+	// If a Collector encounters an error while executing this method, it
+	// must send an invalid descriptor (created with NewInvalidDesc) to
+	// signal the error to the registry.
 	Describe(chan<- *Desc)
 	// Collect is called by the Prometheus registry when collecting
 	// metrics. The implementation sends each collected metric via the
 	// provided channel and returns once the last metric has been sent. The
-	// descriptor of each sent metric is one of those returned by
-	// Describe. Returned metrics that share the same descriptor must differ
-	// in their variable label values. This method may be called
-	// concurrently and must therefore be implemented in a concurrency safe
-	// way. Blocking occurs at the expense of total performance of rendering
-	// all registered metrics. Ideally, Collector implementations support
-	// concurrent readers.
+	// descriptor of each sent metric is one of those returned by Describe
+	// (unless the Collector is unchecked, see above). Returned metrics that
+	// share the same descriptor must differ in their variable label
+	// values.
+	//
+	// This method may be called concurrently and must therefore be
+	// implemented in a concurrency safe way. Blocking occurs at the expense
+	// of total performance of rendering all registered metrics. Ideally,
+	// Collector implementations support concurrent readers.
 	Collect(chan<- Metric)
 }
 
+// DescribeByCollect is a helper to implement the Describe method of a custom
+// Collector. It collects the metrics from the provided Collector and sends
+// their descriptors to the provided channel.
+//
+// If a Collector collects the same metrics throughout its lifetime, its
+// Describe method can simply be implemented as:
+//
+//   func (c customCollector) Describe(ch chan<- *Desc) {
+//   	DescribeByCollect(c, ch)
+//   }
+//
+// However, this will not work if the metrics collected change dynamically over
+// the lifetime of the Collector in a way that their combined set of descriptors
+// changes as well. The shortcut implementation will then violate the contract
+// of the Describe method. If a Collector sometimes collects no metrics at all
+// (for example vectors like CounterVec, GaugeVec, etc., which only collect
+// metrics after a metric with a fully specified label set has been accessed),
+// it might even get registered as an unchecked Collector (cf. the Register
+// method of the Registerer interface). Hence, only use this shortcut
+// implementation of Describe if you are certain to fulfill the contract.
+//
+// The Collector example demonstrates a use of DescribeByCollect.
+func DescribeByCollect(c Collector, descs chan<- *Desc) {
+	metrics := make(chan Metric)
+	go func() {
+		c.Collect(metrics)
+		close(metrics)
+	}()
+	for m := range metrics {
+		descs <- m.Desc()
+	}
+}
+
 // selfCollector implements Collector for a single Metric so that the Metric
 // collects itself. Add it as an anonymous field to a struct that implements
 // Metric, and call init with the Metric itself as an argument.

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -15,6 +15,10 @@ package prometheus
 
 import (
 	"errors"
+	"math"
+	"sync/atomic"
+
+	dto "github.com/prometheus/client_model/go"
 )
 
 // Counter is a Metric that represents a single numerical value that only ever
@@ -42,6 +46,14 @@ type Counter interface {
 type CounterOpts Opts
 
 // NewCounter creates a new Counter based on the provided CounterOpts.
+//
+// The returned implementation tracks the counter value in two separate
+// variables, a float64 and a uint64. The latter is used to track calls of the
+// Inc method and calls of the Add method with a value that can be represented
+// as a uint64. This allows atomic increments of the counter with optimal
+// performance. (It is common to have an Inc call in very hot execution paths.)
+// Both internal tracking values are added up in the Write method. This has to
+// be taken into account when it comes to precision and overflow behavior.
 func NewCounter(opts CounterOpts) Counter {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -49,20 +61,58 @@ func NewCounter(opts CounterOpts) Counter {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &counter{value: value{desc: desc, valType: CounterValue, labelPairs: desc.constLabelPairs}}
+	result := &counter{desc: desc, labelPairs: desc.constLabelPairs}
 	result.init(result) // Init self-collection.
 	return result
 }
 
 type counter struct {
-	value
+	// valBits contains the bits of the represented float64 value, while
+	// valInt stores values that are exact integers. Both have to go first
+	// in the struct to guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+	valInt  uint64
+
+	selfCollector
+	desc *Desc
+
+	labelPairs []*dto.LabelPair
+}
+
+func (c *counter) Desc() *Desc {
+	return c.desc
 }
 
 func (c *counter) Add(v float64) {
 	if v < 0 {
 		panic(errors.New("counter cannot decrease in value"))
 	}
-	c.value.Add(v)
+	ival := uint64(v)
+	if float64(ival) == v {
+		atomic.AddUint64(&c.valInt, ival)
+		return
+	}
+
+	for {
+		oldBits := atomic.LoadUint64(&c.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&c.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (c *counter) Inc() {
+	atomic.AddUint64(&c.valInt, 1)
+}
+
+func (c *counter) Write(out *dto.Metric) error {
+	fval := math.Float64frombits(atomic.LoadUint64(&c.valBits))
+	ival := atomic.LoadUint64(&c.valInt)
+	val := fval + float64(ival)
+
+	return populateMetric(CounterValue, val, c.labelPairs, out)
 }
 
 // CounterVec is a Collector that bundles a set of Counters that all share the
@@ -85,11 +135,10 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	)
 	return &CounterVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			result := &counter{value: value{
-				desc:       desc,
-				valType:    CounterValue,
-				labelPairs: makeLabelPairs(desc, lvs),
-			}}
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.
 			return result
 		}),
@@ -111,7 +160,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 // Counter with the same label values is created later.
 //
 // An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
+// number of VariableLabels in Desc (minus any curried labels).
 //
 // Note that for more than one label value, this method is prone to mistakes
 // caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
@@ -119,8 +168,8 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 // latter has a much more readable (albeit more verbose) syntax, but it comes
 // with a performance overhead (for creating and processing the Labels map).
 // See also the GaugeVec example.
-func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
-	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
+func (v *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Counter), err
 	}
@@ -134,13 +183,13 @@ func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
 // the same as for GetMetricWithLabelValues.
 //
 // An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
+// with those of the VariableLabels in Desc (minus any curried labels).
 //
 // This method is used for the same purpose as
 // GetMetricWithLabelValues(...string). See there for pros and cons of the two
 // methods.
-func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
-	metric, err := m.metricVec.getMetricWith(labels)
+func (v *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Counter), err
 	}
@@ -148,18 +197,57 @@ func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *CounterVec) WithLabelValues(lvs ...string) Counter {
-	return m.metricVec.withLabelValues(lvs...).(Counter)
+func (v *CounterVec) WithLabelValues(lvs ...string) Counter {
+	c, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return c
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *CounterVec) With(labels Labels) Counter {
-	return m.metricVec.with(labels).(Counter)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *CounterVec) With(labels Labels) Counter {
+	c, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the CounterVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *CounterVec) CurryWith(labels Labels) (*CounterVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &CounterVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *CounterVec) MustCurryWith(labels Labels) *CounterVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // CounterFunc is a Counter whose value is determined at collect time by calling a

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -67,24 +67,19 @@ type Desc struct {
 
 // NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
 // and will be reported on registration time. variableLabels and constLabels can
-// be nil if no such labels should be set. fqName and help must not be empty.
+// be nil if no such labels should be set. fqName must not be empty.
 //
 // variableLabels only contain the label names. Their label values are variable
 // and therefore not part of the Desc. (They are managed within the Metric.)
 //
 // For constLabels, the label values are constant. Therefore, they are fully
-// specified in the Desc. See the Opts documentation for the implications of
-// constant labels.
+// specified in the Desc. See the Collector example for a usage pattern.
 func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc {
 	d := &Desc{
 		fqName:         fqName,
 		help:           help,
 		variableLabels: variableLabels,
 	}
-	if help == "" {
-		d.err = errors.New("empty help string")
-		return d
-	}
 	if !model.IsValidMetricName(model.LabelValue(fqName)) {
 		d.err = fmt.Errorf("%q is not a valid metric name", fqName)
 		return d
@@ -98,7 +93,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// First add only the const label names and sort them...
 	for labelName := range constLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, labelName)
@@ -120,7 +115,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// dimension with a different mix between preset and variable labels.
 	for _, labelName := range variableLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, "$"+labelName)
@@ -157,7 +152,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(LabelPairSorter(d.constLabelPairs))
+	sort.Sort(labelPairSorter(d.constLabelPairs))
 	return d
 }
 

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -11,10 +11,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package prometheus provides metrics primitives to instrument code for
-// monitoring. It also offers a registry for metrics. Sub-packages allow to
-// expose the registered metrics via HTTP (package promhttp) or push them to a
-// Pushgateway (package push).
+// Package prometheus is the core instrumentation package. It provides metrics
+// primitives to instrument code for monitoring. It also offers a registry for
+// metrics. Sub-packages allow to expose the registered metrics via HTTP
+// (package promhttp) or push them to a Pushgateway (package push). There is
+// also a sub-package promauto, which provides metrics constructors with
+// automatic registration.
 //
 // All exported functions and methods are safe to be used concurrently unless
 // specified otherwise.
@@ -72,7 +74,10 @@
 // The number of exported identifiers in this package might appear a bit
 // overwhelming. However, in addition to the basic plumbing shown in the example
 // above, you only need to understand the different metric types and their
-// vector versions for basic usage.
+// vector versions for basic usage. Furthermore, if you are not concerned with
+// fine-grained control of when and how to register metrics with the registry,
+// have a look at the promauto package, which will effectively allow you to
+// ignore registration altogether in simple cases.
 //
 // Above, you have already touched the Counter and the Gauge. There are two more
 // advanced metric types: the Summary and Histogram. A more thorough description
@@ -116,7 +121,17 @@
 // NewConstSummary (and their respective Must… versions). That will happen in
 // the Collect method. The Describe method has to return separate Desc
 // instances, representative of the “throw-away” metrics to be created later.
-// NewDesc comes in handy to create those Desc instances.
+// NewDesc comes in handy to create those Desc instances. Alternatively, you
+// could return no Desc at all, which will mark the Collector “unchecked”.  No
+// checks are performed at registration time, but metric consistency will still
+// be ensured at scrape time, i.e. any inconsistencies will lead to scrape
+// errors. Thus, with unchecked Collectors, the responsibility to not collect
+// metrics that lead to inconsistencies in the total scrape result lies with the
+// implementer of the Collector. While this is not a desirable state, it is
+// sometimes necessary. The typical use case is a situation where the exact
+// metrics to be returned by a Collector cannot be predicted at registration
+// time, but the implementer has sufficient knowledge of the whole system to
+// guarantee metric consistency.
 //
 // The Collector example illustrates the use case. You can also look at the
 // source code of the processCollector (mirroring process metrics), the

vendor/github.com/prometheus/client_golang/prometheus/fnv.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 // Inline and byte-free variant of hash/fnv's fnv64a.

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -13,6 +13,14 @@
 
 package prometheus
 
+import (
+	"math"
+	"sync/atomic"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
 // Gauge is a Metric that represents a single numerical value that can
 // arbitrarily go up and down.
 //
@@ -48,13 +56,74 @@ type Gauge interface {
 type GaugeOpts Opts
 
 // NewGauge creates a new Gauge based on the provided GaugeOpts.
+//
+// The returned implementation is optimized for a fast Set method. If you have a
+// choice for managing the value of a Gauge via Set vs. Inc/Dec/Add/Sub, pick
+// the former. For example, the Inc method of the returned Gauge is slower than
+// the Inc method of a Counter returned by NewCounter. This matches the typical
+// scenarios for Gauges and Counters, where the former tends to be Set-heavy and
+// the latter Inc-heavy.
 func NewGauge(opts GaugeOpts) Gauge {
-	return newValue(NewDesc(
+	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
 		nil,
 		opts.ConstLabels,
-	), GaugeValue, 0)
+	)
+	result := &gauge{desc: desc, labelPairs: desc.constLabelPairs}
+	result.init(result) // Init self-collection.
+	return result
+}
+
+type gauge struct {
+	// valBits contains the bits of the represented float64 value. It has
+	// to go first in the struct to guarantee alignment for atomic
+	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+
+	selfCollector
+
+	desc       *Desc
+	labelPairs []*dto.LabelPair
+}
+
+func (g *gauge) Desc() *Desc {
+	return g.desc
+}
+
+func (g *gauge) Set(val float64) {
+	atomic.StoreUint64(&g.valBits, math.Float64bits(val))
+}
+
+func (g *gauge) SetToCurrentTime() {
+	g.Set(float64(time.Now().UnixNano()) / 1e9)
+}
+
+func (g *gauge) Inc() {
+	g.Add(1)
+}
+
+func (g *gauge) Dec() {
+	g.Add(-1)
+}
+
+func (g *gauge) Add(val float64) {
+	for {
+		oldBits := atomic.LoadUint64(&g.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
+		if atomic.CompareAndSwapUint64(&g.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (g *gauge) Sub(val float64) {
+	g.Add(val * -1)
+}
+
+func (g *gauge) Write(out *dto.Metric) error {
+	val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
+	return populateMetric(GaugeValue, val, g.labelPairs, out)
 }
 
 // GaugeVec is a Collector that bundles a set of Gauges that all share the same
@@ -77,7 +146,12 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	)
 	return &GaugeVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			return newValue(desc, GaugeValue, 0, lvs...)
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &gauge{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
+			result.init(result) // Init self-collection.
+			return result
 		}),
 	}
 }
@@ -98,15 +172,15 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 // example.
 //
 // An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
+// number of VariableLabels in Desc (minus any curried labels).
 //
 // Note that for more than one label value, this method is prone to mistakes
 // caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
 // an alternative to avoid that type of mistake. For higher label numbers, the
 // latter has a much more readable (albeit more verbose) syntax, but it comes
 // with a performance overhead (for creating and processing the Labels map).
-func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
-	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
+func (v *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
@@ -120,13 +194,13 @@ func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
 // the same as for GetMetricWithLabelValues.
 //
 // An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
+// with those of the VariableLabels in Desc (minus any curried labels).
 //
 // This method is used for the same purpose as
 // GetMetricWithLabelValues(...string). See there for pros and cons of the two
 // methods.
-func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
-	metric, err := m.metricVec.getMetricWith(labels)
+func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
@@ -134,18 +208,57 @@ func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge {
-	return m.metricVec.withLabelValues(lvs...).(Gauge)
+func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge {
+	g, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return g
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *GaugeVec) With(labels Labels) Gauge {
-	return m.metricVec.with(labels).(Gauge)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *GaugeVec) With(labels Labels) Gauge {
+	g, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return g
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the GaugeVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *GaugeVec) CurryWith(labels Labels) (*GaugeVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &GaugeVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *GaugeVec) MustCurryWith(labels Labels) *GaugeVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // GaugeFunc is a Gauge whose value is determined at collect time by calling a

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -1,9 +1,22 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 import (
-	"fmt"
 	"runtime"
 	"runtime/debug"
+	"sync"
 	"time"
 )
 
@@ -13,12 +26,41 @@ type goCollector struct {
 	gcDesc         *Desc
 	goInfoDesc     *Desc
 
-	// metrics to describe and collect
-	metrics memStatsMetrics
+	// ms... are memstats related.
+	msLast          *runtime.MemStats // Previously collected memstats.
+	msLastTimestamp time.Time
+	msMtx           sync.Mutex // Protects msLast and msLastTimestamp.
+	msMetrics       memStatsMetrics
+	msRead          func(*runtime.MemStats) // For mocking in tests.
+	msMaxWait       time.Duration           // Wait time for fresh memstats.
+	msMaxAge        time.Duration           // Maximum allowed age of old memstats.
 }
 
-// NewGoCollector returns a collector which exports metrics about the current
-// go process.
+// NewGoCollector returns a collector that exports metrics about the current Go
+// process. This includes memory stats. To collect those, runtime.ReadMemStats
+// is called. This requires to “stop the world”, which usually only happens for
+// garbage collection (GC). Take the following implications into account when
+// deciding whether to use the Go collector:
+//
+// 1. The performance impact of stopping the world is the more relevant the more
+// frequently metrics are collected. However, with Go1.9 or later the
+// stop-the-world time per metrics collection is very short (~25µs) so that the
+// performance impact will only matter in rare cases. However, with older Go
+// versions, the stop-the-world duration depends on the heap size and can be
+// quite significant (~1.7 ms/GiB as per
+// https://go-review.googlesource.com/c/go/+/34937).
+//
+// 2. During an ongoing GC, nothing else can stop the world. Therefore, if the
+// metrics collection happens to coincide with GC, it will only complete after
+// GC has finished. Usually, GC is fast enough to not cause problems. However,
+// with a very large heap, GC might take multiple seconds, which is enough to
+// cause scrape timeouts in common setups. To avoid this problem, the Go
+// collector will use the memstats from a previous collection if
+// runtime.ReadMemStats takes more than 1s. However, if there are no previously
+// collected memstats, or their collection is more than 5m ago, the collection
+// will block until runtime.ReadMemStats succeeds. (The problem might be solved
+// in Go1.13, see https://github.com/golang/go/issues/19812 for the related Go
+// issue.)
 func NewGoCollector() Collector {
 	return &goCollector{
 		goroutinesDesc: NewDesc(
@@ -37,7 +79,11 @@ func NewGoCollector() Collector {
 			"go_info",
 			"Information about the Go environment.",
 			nil, Labels{"version": runtime.Version()}),
-		metrics: memStatsMetrics{
+		msLast:    &runtime.MemStats{},
+		msRead:    runtime.ReadMemStats,
+		msMaxWait: time.Second,
+		msMaxAge:  5 * time.Minute,
+		msMetrics: memStatsMetrics{
 			{
 				desc: NewDesc(
 					memstatNamespace("alloc_bytes"),
@@ -236,7 +282,7 @@ func NewGoCollector() Collector {
 }
 
 func memstatNamespace(s string) string {
-	return fmt.Sprintf("go_memstats_%s", s)
+	return "go_memstats_" + s
 }
 
 // Describe returns all descriptions of the collector.
@@ -245,13 +291,27 @@ func (c *goCollector) Describe(ch chan<- *Desc) {
 	ch <- c.threadsDesc
 	ch <- c.gcDesc
 	ch <- c.goInfoDesc
-	for _, i := range c.metrics {
+	for _, i := range c.msMetrics {
 		ch <- i.desc
 	}
 }
 
 // Collect returns the current state of all metrics of the collector.
 func (c *goCollector) Collect(ch chan<- Metric) {
+	var (
+		ms   = &runtime.MemStats{}
+		done = make(chan struct{})
+	)
+	// Start reading memstats first as it might take a while.
+	go func() {
+		c.msRead(ms)
+		c.msMtx.Lock()
+		c.msLast = ms
+		c.msLastTimestamp = time.Now()
+		c.msMtx.Unlock()
+		close(done)
+	}()
+
 	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
 	n, _ := runtime.ThreadCreateProfile(nil)
 	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
@@ -265,13 +325,35 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 		quantiles[float64(idx+1)/float64(len(stats.PauseQuantiles)-1)] = pq.Seconds()
 	}
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
-	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
+	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
 
 	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
 
-	ms := &runtime.MemStats{}
-	runtime.ReadMemStats(ms)
-	for _, i := range c.metrics {
+	timer := time.NewTimer(c.msMaxWait)
+	select {
+	case <-done: // Our own ReadMemStats succeeded in time. Use it.
+		timer.Stop() // Important for high collection frequencies to not pile up timers.
+		c.msCollect(ch, ms)
+		return
+	case <-timer.C: // Time out, use last memstats if possible. Continue below.
+	}
+	c.msMtx.Lock()
+	if time.Since(c.msLastTimestamp) < c.msMaxAge {
+		// Last memstats are recent enough. Collect from them under the lock.
+		c.msCollect(ch, c.msLast)
+		c.msMtx.Unlock()
+		return
+	}
+	// If we are here, the last memstats are too old or don't exist. We have
+	// to wait until our own ReadMemStats finally completes. For that to
+	// happen, we have to release the lock.
+	c.msMtx.Unlock()
+	<-done
+	c.msCollect(ch, ms)
+}
+
+func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
+	for _, i := range c.msMetrics {
 		ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
 	}
 }
@@ -282,3 +364,33 @@ type memStatsMetrics []struct {
 	eval    func(*runtime.MemStats) float64
 	valType ValueType
 }
+
+// NewBuildInfoCollector returns a collector collecting a single metric
+// "go_build_info" with the constant value 1 and three labels "path", "version",
+// and "checksum". Their label values contain the main module path, version, and
+// checksum, respectively. The labels will only have meaningful values if the
+// binary is built with Go module support and from source code retrieved from
+// the source repository (rather than the local file system). This is usually
+// accomplished by building from outside of GOPATH, specifying the full address
+// of the main package, e.g. "GO111MODULE=on go run
+// github.com/prometheus/client_golang/examples/random". If built without Go
+// module support, all label values will be "unknown". If built with Go module
+// support but using the source code from the local file system, the "path" will
+// be set appropriately, but "checksum" will be empty and "version" will be
+// "(devel)".
+//
+// This collector uses only the build information for the main module. See
+// https://github.com/povilasv/prommod for an example of a collector for the
+// module dependencies.
+func NewBuildInfoCollector() Collector {
+	path, version, sum := readBuildInfo()
+	c := &selfCollector{MustNewConstMetric(
+		NewDesc(
+			"go_build_info",
+			"Build information about the main Go module.",
+			nil, Labels{"path": path, "version": version, "checksum": sum},
+		),
+		GaugeValue, 1)}
+	c.init(c.self)
+	return c
+}

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -16,7 +16,9 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
+	"sync"
 	"sync/atomic"
 
 	"github.com/golang/protobuf/proto"
@@ -108,8 +110,9 @@ func ExponentialBuckets(start, factor float64, count int) []float64 {
 }
 
 // HistogramOpts bundles the options for creating a Histogram metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. All other fields are optional
+// and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type HistogramOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Histogram (created by joining these components with
@@ -120,29 +123,22 @@ type HistogramOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Histogram. Mandatory!
+	// Help provides information about this Histogram.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Histogram. Histograms with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// HistogramVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Histograms with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Buckets defines the buckets into which observations are counted. Each
@@ -169,7 +165,7 @@ func NewHistogram(opts HistogramOpts) Histogram {
 
 func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogram {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -191,6 +187,7 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 		desc:        desc,
 		upperBounds: opts.Buckets,
 		labelPairs:  makeLabelPairs(desc, labelValues),
+		counts:      [2]*histogramCounts{&histogramCounts{}, &histogramCounts{}},
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -207,30 +204,56 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 			}
 		}
 	}
-	// Finally we know the final length of h.upperBounds and can make counts.
-	h.counts = make([]uint64, len(h.upperBounds))
+	// Finally we know the final length of h.upperBounds and can make buckets
+	// for both counts:
+	h.counts[0].buckets = make([]uint64, len(h.upperBounds))
+	h.counts[1].buckets = make([]uint64, len(h.upperBounds))
 
 	h.init(h) // Init self-collection.
 	return h
 }
 
-type histogram struct {
+type histogramCounts struct {
 	// sumBits contains the bits of the float64 representing the sum of all
 	// observations. sumBits and count have to go first in the struct to
 	// guarantee alignment for atomic operations.
 	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	sumBits uint64
 	count   uint64
+	buckets []uint64
+}
+
+type histogram struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// histogramCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the histogram) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+	//
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
 
 	selfCollector
-	// Note that there is no mutex required.
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
 
-	desc *Desc
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*histogramCounts
 
 	upperBounds []float64
-	counts      []uint64
-
-	labelPairs []*dto.LabelPair
+	labelPairs  []*dto.LabelPair
 }
 
 func (h *histogram) Desc() *Desc {
@@ -248,36 +271,84 @@ func (h *histogram) Observe(v float64) {
 	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
 	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
 	i := sort.SearchFloat64s(h.upperBounds, v)
-	if i < len(h.counts) {
-		atomic.AddUint64(&h.counts[i], 1)
+
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1)
+	hotCounts := h.counts[n>>63]
+
+	if i < len(h.upperBounds) {
+		atomic.AddUint64(&hotCounts.buckets[i], 1)
 	}
-	atomic.AddUint64(&h.count, 1)
 	for {
-		oldBits := atomic.LoadUint64(&h.sumBits)
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
 		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&h.sumBits, oldBits, newBits) {
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
 			break
 		}
 	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
 }
 
 func (h *histogram) Write(out *dto.Metric) error {
-	his := &dto.Histogram{}
-	buckets := make([]*dto.Bucket, len(h.upperBounds))
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	h.writeMtx.Lock()
+	defer h.writeMtx.Unlock()
 
-	his.SampleSum = proto.Float64(math.Float64frombits(atomic.LoadUint64(&h.sumBits)))
-	his.SampleCount = proto.Uint64(atomic.LoadUint64(&h.count))
-	var count uint64
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := h.counts[n>>63]
+	coldCounts := h.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	his := &dto.Histogram{
+		Bucket:      make([]*dto.Bucket, len(h.upperBounds)),
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+	var cumCount uint64
 	for i, upperBound := range h.upperBounds {
-		count += atomic.LoadUint64(&h.counts[i])
-		buckets[i] = &dto.Bucket{
-			CumulativeCount: proto.Uint64(count),
+		cumCount += atomic.LoadUint64(&coldCounts.buckets[i])
+		his.Bucket[i] = &dto.Bucket{
+			CumulativeCount: proto.Uint64(cumCount),
 			UpperBound:      proto.Float64(upperBound),
 		}
 	}
-	his.Bucket = buckets
+
 	out.Histogram = his
 	out.Label = h.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + his.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	for i := range h.upperBounds {
+		atomic.AddUint64(&hotCounts.buckets[i], atomic.LoadUint64(&coldCounts.buckets[i]))
+		atomic.StoreUint64(&coldCounts.buckets[i], 0)
+	}
 	return nil
 }
 
@@ -322,7 +393,7 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 // example.
 //
 // An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
+// number of VariableLabels in Desc (minus any curried labels).
 //
 // Note that for more than one label value, this method is prone to mistakes
 // caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
@@ -330,8 +401,8 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 // latter has a much more readable (albeit more verbose) syntax, but it comes
 // with a performance overhead (for creating and processing the Labels map).
 // See also the GaugeVec example.
-func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
-	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
+func (v *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Observer), err
 	}
@@ -345,13 +416,13 @@ func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error)
 // are the same as for GetMetricWithLabelValues.
 //
 // An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
+// with those of the VariableLabels in Desc (minus any curried labels).
 //
 // This method is used for the same purpose as
 // GetMetricWithLabelValues(...string). See there for pros and cons of the two
 // methods.
-func (m *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
-	metric, err := m.metricVec.getMetricWith(labels)
+func (v *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Observer), err
 	}
@@ -359,18 +430,57 @@ func (m *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *HistogramVec) WithLabelValues(lvs ...string) Observer {
-	return m.metricVec.withLabelValues(lvs...).(Observer)
+func (v *HistogramVec) WithLabelValues(lvs ...string) Observer {
+	h, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return h
 }
 
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *HistogramVec) With(labels Labels) Observer {
-	return m.metricVec.with(labels).(Observer)
+// With works as GetMetricWith but panics where GetMetricWithLabels would have
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *HistogramVec) With(labels Labels) Observer {
+	h, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the HistogramVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *HistogramVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &HistogramVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *HistogramVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constHistogram struct {
@@ -422,7 +532,7 @@ func (h *constHistogram) Write(out *dto.Metric) error {
 // bucket.
 //
 // NewConstHistogram returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstHistogram(
 	desc *Desc,
 	count uint64,
@@ -430,6 +540,9 @@ func NewConstHistogram(
 	buckets map[float64]uint64,
 	labelValues ...string,
 ) (Metric, error) {
+	if desc.err != nil {
+		return nil, desc.err
+	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -15,9 +15,7 @@ package prometheus
 
 import (
 	"bufio"
-	"bytes"
 	"compress/gzip"
-	"fmt"
 	"io"
 	"net"
 	"net/http"
@@ -36,24 +34,14 @@ import (
 
 const (
 	contentTypeHeader     = "Content-Type"
-	contentLengthHeader   = "Content-Length"
 	contentEncodingHeader = "Content-Encoding"
 	acceptEncodingHeader  = "Accept-Encoding"
 )
 
-var bufPool sync.Pool
-
-func getBuf() *bytes.Buffer {
-	buf := bufPool.Get()
-	if buf == nil {
-		return &bytes.Buffer{}
-	}
-	return buf.(*bytes.Buffer)
-}
-
-func giveBuf(buf *bytes.Buffer) {
-	buf.Reset()
-	bufPool.Put(buf)
+var gzipPool = sync.Pool{
+	New: func() interface{} {
+		return gzip.NewWriter(nil)
+	},
 }
 
 // Handler returns an HTTP handler for the DefaultGatherer. It is
@@ -61,69 +49,50 @@ func giveBuf(buf *bytes.Buffer) {
 // name).
 //
 // Deprecated: Please note the issues described in the doc comment of
-// InstrumentHandler. You might want to consider using promhttp.Handler instead
-// (which is not instrumented, but can be instrumented with the tooling provided
-// in package promhttp).
+// InstrumentHandler. You might want to consider using promhttp.Handler instead.
 func Handler() http.Handler {
 	return InstrumentHandler("prometheus", UninstrumentedHandler())
 }
 
 // UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
 //
-// Deprecated: Use promhttp.Handler instead. See there for further documentation.
+// Deprecated: Use promhttp.HandlerFor(DefaultGatherer, promhttp.HandlerOpts{})
+// instead. See there for further documentation.
 func UninstrumentedHandler() http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+	return http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
 		mfs, err := DefaultGatherer.Gather()
 		if err != nil {
-			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
+			httpError(rsp, err)
 			return
 		}
 
 		contentType := expfmt.Negotiate(req.Header)
-		buf := getBuf()
-		defer giveBuf(buf)
-		writer, encoding := decorateWriter(req, buf)
-		enc := expfmt.NewEncoder(writer, contentType)
-		var lastErr error
+		header := rsp.Header()
+		header.Set(contentTypeHeader, string(contentType))
+
+		w := io.Writer(rsp)
+		if gzipAccepted(req.Header) {
+			header.Set(contentEncodingHeader, "gzip")
+			gz := gzipPool.Get().(*gzip.Writer)
+			defer gzipPool.Put(gz)
+
+			gz.Reset(w)
+			defer gz.Close()
+
+			w = gz
+		}
+
+		enc := expfmt.NewEncoder(w, contentType)
+
 		for _, mf := range mfs {
 			if err := enc.Encode(mf); err != nil {
-				lastErr = err
-				http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
+				httpError(rsp, err)
 				return
 			}
 		}
-		if closer, ok := writer.(io.Closer); ok {
-			closer.Close()
-		}
-		if lastErr != nil && buf.Len() == 0 {
-			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
-			return
-		}
-		header := w.Header()
-		header.Set(contentTypeHeader, string(contentType))
-		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
-		if encoding != "" {
-			header.Set(contentEncodingHeader, encoding)
-		}
-		w.Write(buf.Bytes())
 	})
 }
 
-// decorateWriter wraps a writer to handle gzip compression if requested.  It
-// returns the decorated writer and the appropriate "Content-Encoding" header
-// (which is empty if no compression is enabled).
-func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string) {
-	header := request.Header.Get(acceptEncodingHeader)
-	parts := strings.Split(header, ",")
-	for _, part := range parts {
-		part := strings.TrimSpace(part)
-		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return gzip.NewWriter(writer), "gzip"
-		}
-	}
-	return writer, ""
-}
-
 var instLabels = []string{"method", "code"}
 
 type nower interface {
@@ -140,16 +109,6 @@ var now nower = nowFunc(func() time.Time {
 	return time.Now()
 })
 
-func nowSeries(t ...time.Time) nower {
-	return nowFunc(func() time.Time {
-		defer func() {
-			t = t[1:]
-		}()
-
-		return t[0]
-	})
-}
-
 // InstrumentHandler wraps the given HTTP handler for instrumentation. It
 // registers four metric collectors (if not already done) and reports HTTP
 // metrics to the (newly or already) registered collectors: http_requests_total
@@ -160,21 +119,14 @@ func nowSeries(t ...time.Time) nower {
 // (label name "method") and HTTP status code (label name "code").
 //
 // Deprecated: InstrumentHandler has several issues. Use the tooling provided in
-// package promhttp instead. The issues are the following:
-//
-// - It uses Summaries rather than Histograms. Summaries are not useful if
-// aggregation across multiple instances is required.
-//
-// - It uses microseconds as unit, which is deprecated and should be replaced by
-// seconds.
-//
-// - The size of the request is calculated in a separate goroutine. Since this
-// calculator requires access to the request header, it creates a race with
-// any writes to the header performed during request handling.
-// httputil.ReverseProxy is a prominent example for a handler
-// performing such writes.
-//
-// - It has additional issues with HTTP/2, cf.
+// package promhttp instead. The issues are the following: (1) It uses Summaries
+// rather than Histograms. Summaries are not useful if aggregation across
+// multiple instances is required. (2) It uses microseconds as unit, which is
+// deprecated and should be replaced by seconds. (3) The size of the request is
+// calculated in a separate goroutine. Since this calculator requires access to
+// the request header, it creates a race with any writes to the header performed
+// during request handling.  httputil.ReverseProxy is a prominent example for a
+// handler performing such writes. (4) It has additional issues with HTTP/2, cf.
 // https://github.com/prometheus/client_golang/issues/272.
 func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
 	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
@@ -318,7 +270,7 @@ func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.Respo
 }
 
 func computeApproximateRequestSize(r *http.Request) <-chan int {
-	// Get URL length in current go routine for avoiding a race condition.
+	// Get URL length in current goroutine for avoiding a race condition.
 	// HandlerFunc that runs in parallel may modify the URL.
 	s := 0
 	if r.URL != nil {
@@ -353,10 +305,9 @@ func computeApproximateRequestSize(r *http.Request) <-chan int {
 type responseWriterDelegator struct {
 	http.ResponseWriter
 
-	handler, method string
-	status          int
-	written         int64
-	wroteHeader     bool
+	status      int
+	written     int64
+	wroteHeader bool
 }
 
 func (r *responseWriterDelegator) WriteHeader(code int) {
@@ -379,6 +330,8 @@ type fancyResponseWriterDelegator struct {
 }
 
 func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool {
+	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
+	//remove support from client_golang yet.
 	return f.ResponseWriter.(http.CloseNotifier).CloseNotify()
 }
 
@@ -522,3 +475,31 @@ func sanitizeCode(s int) string {
 		return strconv.Itoa(s)
 	}
 }
+
+// gzipAccepted returns whether the client will accept gzip-encoded content.
+func gzipAccepted(header http.Header) bool {
+	a := header.Get(acceptEncodingHeader)
+	parts := strings.Split(a, ",")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
+			return true
+		}
+	}
+	return false
+}
+
+// httpError removes any content-encoding header and then calls http.Error with
+// the provided error and http.StatusInternalServerErrer. Error contents is
+// supposed to be uncompressed plain text. However, same as with a plain
+// http.Error, any header settings will be void if the header has already been
+// sent. The error message will still be written to the writer, but it will
+// probably be of limited use.
+func httpError(rsp http.ResponseWriter, err error) {
+	rsp.Header().Del(contentEncodingHeader)
+	http.Error(
+		rsp,
+		"An error has occurred while serving metrics:\n\n"+err.Error(),
+		http.StatusInternalServerError,
+	)
+}

vendor/github.com/prometheus/client_golang/prometheus/internal/metric.go

@@ -0,0 +1,85 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"sort"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// metricSorter is a sortable slice of *dto.Metric.
+type metricSorter []*dto.Metric
+
+func (s metricSorter) Len() int {
+	return len(s)
+}
+
+func (s metricSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s metricSorter) Less(i, j int) bool {
+	if len(s[i].Label) != len(s[j].Label) {
+		// This should not happen. The metrics are
+		// inconsistent. However, we have to deal with the fact, as
+		// people might use custom collectors or metric family injection
+		// to create inconsistent metrics. So let's simply compare the
+		// number of labels in this case. That will still yield
+		// reproducible sorting.
+		return len(s[i].Label) < len(s[j].Label)
+	}
+	for n, lp := range s[i].Label {
+		vi := lp.GetValue()
+		vj := s[j].Label[n].GetValue()
+		if vi != vj {
+			return vi < vj
+		}
+	}
+
+	// We should never arrive here. Multiple metrics with the same
+	// label set in the same scrape will lead to undefined ingestion
+	// behavior. However, as above, we have to provide stable sorting
+	// here, even for inconsistent metrics. So sort equal metrics
+	// by their timestamp, with missing timestamps (implying "now")
+	// coming last.
+	if s[i].TimestampMs == nil {
+		return false
+	}
+	if s[j].TimestampMs == nil {
+		return true
+	}
+	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
+}
+
+// NormalizeMetricFamilies returns a MetricFamily slice with empty
+// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
+// the slice, with the contained Metrics sorted within each MetricFamily.
+func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
+	for _, mf := range metricFamiliesByName {
+		sort.Sort(metricSorter(mf.Metric))
+	}
+	names := make([]string, 0, len(metricFamiliesByName))
+	for name, mf := range metricFamiliesByName {
+		if len(mf.Metric) > 0 {
+			names = append(names, name)
+		}
+	}
+	sort.Strings(names)
+	result := make([]*dto.MetricFamily, 0, len(names))
+	for _, name := range names {
+		result = append(result, metricFamiliesByName[name])
+	}
+	return result
+}

vendor/github.com/prometheus/client_golang/prometheus/labels.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 import (
@@ -24,9 +37,22 @@ const reservedLabelPrefix = "__"
 
 var errInconsistentCardinality = errors.New("inconsistent label cardinality")
 
+func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
+	return fmt.Errorf(
+		"%s: %q has %d variable labels named %q but %d values %q were provided",
+		errInconsistentCardinality, fqName,
+		len(labels), labels,
+		len(labelValues), labelValues,
+	)
+}
+
 func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 	if len(labels) != expectedNumberOfValues {
-		return errInconsistentCardinality
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(labels), labels,
+		)
 	}
 
 	for name, val := range labels {
@@ -40,7 +66,11 @@ func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 
 func validateLabelValues(vals []string, expectedNumberOfValues int) error {
 	if len(vals) != expectedNumberOfValues {
-		return errInconsistentCardinality
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(vals), vals,
+		)
 	}
 
 	for _, val := range vals {

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -15,6 +15,9 @@ package prometheus
 
 import (
 	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
 )
@@ -43,9 +46,8 @@ type Metric interface {
 	// While populating dto.Metric, it is the responsibility of the
 	// implementation to ensure validity of the Metric protobuf (like valid
 	// UTF-8 strings or syntactically valid metric and label names). It is
-	// recommended to sort labels lexicographically. (Implementers may find
-	// LabelPairSorter useful for that.) Callers of Write should still make
-	// sure of sorting if they depend on it.
+	// recommended to sort labels lexicographically. Callers of Write should
+	// still make sure of sorting if they depend on it.
 	Write(*dto.Metric) error
 	// TODO(beorn7): The original rationale of passing in a pre-allocated
 	// dto.Metric protobuf to save allocations has disappeared. The
@@ -57,8 +59,9 @@ type Metric interface {
 // implementation XXX has its own XXXOpts type, but in most cases, it is just be
 // an alias of this type (which might change when the requirement arises.)
 //
-// It is mandatory to set Name and Help to a non-empty string. All other fields
-// are optional and can safely be left at their zero value.
+// It is mandatory to set Name to a non-empty string. All other fields are
+// optional and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type Opts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Metric (created by joining these components with
@@ -69,7 +72,7 @@ type Opts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this metric. Mandatory!
+	// Help provides information about this metric.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -79,20 +82,12 @@ type Opts struct {
 	// with the same fully-qualified name must have the same label names in
 	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a metric
-	// vector collector (like CounterVec, GaugeVec, UntypedVec). ConstLabels
-	// serve only special purposes. One is for the special case where the
-	// value of a label does not change during the lifetime of a process,
-	// e.g. if the revision of the running binary is put into a
-	// label. Another, more advanced purpose is if more than one Collector
-	// needs to collect Metrics with the same fully-qualified name. In that
-	// case, those Metrics must differ in the values of their
-	// ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
 	ConstLabels Labels
 }
 
@@ -118,37 +113,22 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }
 
-// LabelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers. This is useful for implementing the Write method of
-// custom metrics.
-type LabelPairSorter []*dto.LabelPair
+// labelPairSorter implements sort.Interface. It is used to sort a slice of
+// dto.LabelPair pointers.
+type labelPairSorter []*dto.LabelPair
 
-func (s LabelPairSorter) Len() int {
+func (s labelPairSorter) Len() int {
 	return len(s)
 }
 
-func (s LabelPairSorter) Swap(i, j int) {
+func (s labelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }
 
-func (s LabelPairSorter) Less(i, j int) bool {
+func (s labelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 
-type hashSorter []uint64
-
-func (s hashSorter) Len() int {
-	return len(s)
-}
-
-func (s hashSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s hashSorter) Less(i, j int) bool {
-	return s[i] < s[j]
-}
-
 type invalidMetric struct {
 	desc *Desc
 	err  error
@@ -164,3 +144,31 @@ func NewInvalidMetric(desc *Desc, err error) Metric {
 func (m *invalidMetric) Desc() *Desc { return m.desc }
 
 func (m *invalidMetric) Write(*dto.Metric) error { return m.err }
+
+type timestampedMetric struct {
+	Metric
+	t time.Time
+}
+
+func (m timestampedMetric) Write(pb *dto.Metric) error {
+	e := m.Metric.Write(pb)
+	pb.TimestampMs = proto.Int64(m.t.Unix()*1000 + int64(m.t.Nanosecond()/1000000))
+	return e
+}
+
+// NewMetricWithTimestamp returns a new Metric wrapping the provided Metric in a
+// way that it has an explicit timestamp set to the provided Time. This is only
+// useful in rare cases as the timestamp of a Prometheus metric should usually
+// be set by the Prometheus server during scraping. Exceptions include mirroring
+// metrics with given timestamps from other metric
+// sources.
+//
+// NewMetricWithTimestamp works best with MustNewConstMetric,
+// MustNewConstHistogram, and MustNewConstSummary, see example.
+//
+// Currently, the exposition formats used by Prometheus are limited to
+// millisecond resolution. Thus, the provided time will be rounded down to the
+// next full millisecond value.
+func NewMetricWithTimestamp(t time.Time, m Metric) Metric {
+	return timestampedMetric{Metric: m, t: t}
+}

vendor/github.com/prometheus/client_golang/prometheus/observer.go

@@ -45,6 +45,8 @@ type ObserverVec interface {
 	GetMetricWithLabelValues(lvs ...string) (Observer, error)
 	With(Labels) Observer
 	WithLabelValues(...string) Observer
+	CurryWith(Labels) (ObserverVec, error)
+	MustCurryWith(Labels) ObserverVec
 
 	Collector
 }

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -13,46 +13,74 @@
 
 package prometheus
 
-import "github.com/prometheus/procfs"
+import (
+	"errors"
+	"os"
+
+	"github.com/prometheus/procfs"
+)
 
 type processCollector struct {
-	pid             int
 	collectFn       func(chan<- Metric)
 	pidFn           func() (int, error)
+	reportErrors    bool
 	cpuTotal        *Desc
 	openFDs, maxFDs *Desc
-	vsize, rss      *Desc
+	vsize, maxVsize *Desc
+	rss             *Desc
 	startTime       *Desc
 }
 
-// NewProcessCollector returns a collector which exports the current state of
-// process metrics including cpu, memory and file descriptor usage as well as
-// the process start time for the given process id under the given namespace.
-func NewProcessCollector(pid int, namespace string) Collector {
-	return NewProcessCollectorPIDFn(
-		func() (int, error) { return pid, nil },
-		namespace,
-	)
+// ProcessCollectorOpts defines the behavior of a process metrics collector
+// created with NewProcessCollector.
+type ProcessCollectorOpts struct {
+	// PidFn returns the PID of the process the collector collects metrics
+	// for. It is called upon each collection. By default, the PID of the
+	// current process is used, as determined on construction time by
+	// calling os.Getpid().
+	PidFn func() (int, error)
+	// If non-empty, each of the collected metrics is prefixed by the
+	// provided string and an underscore ("_").
+	Namespace string
+	// If true, any error encountered during collection is reported as an
+	// invalid metric (see NewInvalidMetric). Otherwise, errors are ignored
+	// and the collected metrics will be incomplete. (Possibly, no metrics
+	// will be collected at all.) While that's usually not desired, it is
+	// appropriate for the common "mix-in" of process metrics, where process
+	// metrics are nice to have, but failing to collect them should not
+	// disrupt the collection of the remaining metrics.
+	ReportErrors bool
 }
 
-// NewProcessCollectorPIDFn returns a collector which exports the current state
-// of process metrics including cpu, memory and file descriptor usage as well
-// as the process start time under the given namespace. The given pidFn is
-// called on each collect and is used to determine the process to export
-// metrics for.
-func NewProcessCollectorPIDFn(
-	pidFn func() (int, error),
-	namespace string,
-) Collector {
+// NewProcessCollector returns a collector which exports the current state of
+// process metrics including CPU, memory and file descriptor usage as well as
+// the process start time. The detailed behavior is defined by the provided
+// ProcessCollectorOpts. The zero value of ProcessCollectorOpts creates a
+// collector for the current process with an empty namespace string and no error
+// reporting.
+//
+// Currently, the collector depends on a Linux-style proc filesystem and
+// therefore only exports metrics for Linux.
+//
+// Note: An older version of this function had the following signature:
+//
+//     NewProcessCollector(pid int, namespace string) Collector
+//
+// Most commonly, it was called as
+//
+//     NewProcessCollector(os.Getpid(), "")
+//
+// The following call of the current version is equivalent to the above:
+//
+//     NewProcessCollector(ProcessCollectorOpts{})
+func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 	ns := ""
-	if len(namespace) > 0 {
-		ns = namespace + "_"
+	if len(opts.Namespace) > 0 {
+		ns = opts.Namespace + "_"
 	}
 
-	c := processCollector{
-		pidFn:     pidFn,
-		collectFn: func(chan<- Metric) {},
-
+	c := &processCollector{
+		reportErrors: opts.ReportErrors,
 		cpuTotal: NewDesc(
 			ns+"process_cpu_seconds_total",
 			"Total user and system CPU time spent in seconds.",
@@ -73,6 +101,11 @@ func NewProcessCollectorPIDFn(
 			"Virtual memory size in bytes.",
 			nil, nil,
 		),
+		maxVsize: NewDesc(
+			ns+"process_virtual_memory_max_bytes",
+			"Maximum amount of virtual memory available in bytes.",
+			nil, nil,
+		),
 		rss: NewDesc(
 			ns+"process_resident_memory_bytes",
 			"Resident memory size in bytes.",
@@ -85,12 +118,23 @@ func NewProcessCollectorPIDFn(
 		),
 	}
 
-	// Set up process metric collection if supported by the runtime.
-	if _, err := procfs.NewStat(); err == nil {
-		c.collectFn = c.processCollect
+	if opts.PidFn == nil {
+		pid := os.Getpid()
+		c.pidFn = func() (int, error) { return pid, nil }
+	} else {
+		c.pidFn = opts.PidFn
 	}
 
-	return &c
+	// Set up process metric collection if supported by the runtime.
+	if _, err := procfs.NewDefaultFS(); err == nil {
+		c.collectFn = c.processCollect
+	} else {
+		c.collectFn = func(ch chan<- Metric) {
+			c.reportError(ch, nil, errors.New("process metrics not supported on this platform"))
+		}
+	}
+
+	return c
 }
 
 // Describe returns all descriptions of the collector.
@@ -99,6 +143,7 @@ func (c *processCollector) Describe(ch chan<- *Desc) {
 	ch <- c.openFDs
 	ch <- c.maxFDs
 	ch <- c.vsize
+	ch <- c.maxVsize
 	ch <- c.rss
 	ch <- c.startTime
 }
@@ -108,33 +153,52 @@ func (c *processCollector) Collect(ch chan<- Metric) {
 	c.collectFn(ch)
 }
 
-// TODO(ts): Bring back error reporting by reverting 7faf9e7 as soon as the
-// client allows users to configure the error behavior.
 func (c *processCollector) processCollect(ch chan<- Metric) {
 	pid, err := c.pidFn()
 	if err != nil {
+		c.reportError(ch, nil, err)
 		return
 	}
 
 	p, err := procfs.NewProc(pid)
 	if err != nil {
+		c.reportError(ch, nil, err)
 		return
 	}
 
-	if stat, err := p.NewStat(); err == nil {
+	if stat, err := p.Stat(); err == nil {
 		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
 		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
 		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
 		if startTime, err := stat.StartTime(); err == nil {
 			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
+		} else {
+			c.reportError(ch, c.startTime, err)
 		}
+	} else {
+		c.reportError(ch, nil, err)
 	}
 
 	if fds, err := p.FileDescriptorsLen(); err == nil {
 		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
+	} else {
+		c.reportError(ch, c.openFDs, err)
 	}
 
-	if limits, err := p.NewLimits(); err == nil {
+	if limits, err := p.Limits(); err == nil {
 		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
+		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
+	} else {
+		c.reportError(ch, nil, err)
 	}
 }
+
+func (c *processCollector) reportError(ch chan<- Metric, desc *Desc, err error) {
+	if !c.reportErrors {
+		return
+	}
+	if desc == nil {
+		desc = NewInvalidDesc(err)
+	}
+	ch <- NewInvalidMetric(desc, err)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go

@@ -38,7 +38,6 @@ type delegator interface {
 type responseWriterDelegator struct {
 	http.ResponseWriter
 
-	handler, method    string
 	status             int
 	written            int64
 	wroteHeader        bool
@@ -75,17 +74,20 @@ type closeNotifierDelegator struct{ *responseWriterDelegator }
 type flusherDelegator struct{ *responseWriterDelegator }
 type hijackerDelegator struct{ *responseWriterDelegator }
 type readerFromDelegator struct{ *responseWriterDelegator }
+type pusherDelegator struct{ *responseWriterDelegator }
 
-func (d *closeNotifierDelegator) CloseNotify() <-chan bool {
+func (d closeNotifierDelegator) CloseNotify() <-chan bool {
+	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
+	//remove support from client_golang yet.
 	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
 }
-func (d *flusherDelegator) Flush() {
+func (d flusherDelegator) Flush() {
 	d.ResponseWriter.(http.Flusher).Flush()
 }
-func (d *hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+func (d hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
 	return d.ResponseWriter.(http.Hijacker).Hijack()
 }
-func (d *readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
 	if !d.wroteHeader {
 		d.WriteHeader(http.StatusOK)
 	}
@@ -93,6 +95,9 @@ func (d *readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
 	d.written += n
 	return n, err
 }
+func (d pusherDelegator) Push(target string, opts *http.PushOptions) error {
+	return d.ResponseWriter.(http.Pusher).Push(target, opts)
+}
 
 var pickDelegator = make([]func(*responseWriterDelegator) delegator, 32)
 
@@ -112,7 +117,7 @@ func init() {
 			*responseWriterDelegator
 			http.Flusher
 			http.CloseNotifier
-		}{d, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, flusherDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[hijacker] = func(d *responseWriterDelegator) delegator { // 4
 		return hijackerDelegator{d}
@@ -122,14 +127,14 @@ func init() {
 			*responseWriterDelegator
 			http.Hijacker
 			http.CloseNotifier
-		}{d, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, hijackerDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 6
 		return struct {
 			*responseWriterDelegator
 			http.Hijacker
 			http.Flusher
-		}{d, &hijackerDelegator{d}, &flusherDelegator{d}}
+		}{d, hijackerDelegator{d}, flusherDelegator{d}}
 	}
 	pickDelegator[hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 7
 		return struct {
@@ -137,7 +142,7 @@ func init() {
 			http.Hijacker
 			http.Flusher
 			http.CloseNotifier
-		}{d, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom] = func(d *responseWriterDelegator) delegator { // 8
 		return readerFromDelegator{d}
@@ -147,14 +152,14 @@ func init() {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.CloseNotifier
-		}{d, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, readerFromDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 10
 		return struct {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.Flusher
-		}{d, &readerFromDelegator{d}, &flusherDelegator{d}}
+		}{d, readerFromDelegator{d}, flusherDelegator{d}}
 	}
 	pickDelegator[readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 11
 		return struct {
@@ -162,14 +167,14 @@ func init() {
 			io.ReaderFrom
 			http.Flusher
 			http.CloseNotifier
-		}{d, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 12
 		return struct {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.Hijacker
-		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}}
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 13
 		return struct {
@@ -177,7 +182,7 @@ func init() {
 			io.ReaderFrom
 			http.Hijacker
 			http.CloseNotifier
-		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 14
 		return struct {
@@ -185,7 +190,7 @@ func init() {
 			io.ReaderFrom
 			http.Hijacker
 			http.Flusher
-		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 15
 		return struct {
@@ -194,6 +199,159 @@ func init() {
 			http.Hijacker
 			http.Flusher
 			http.CloseNotifier
-		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
+		return pusherDelegator{d}
+	}
+	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+		}{d, pusherDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+		}{d, pusherDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+		}{d, pusherDelegator{d}, readerFromDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
 	}
 }
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
+	//remove support from client_golang yet.
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+	if _, ok := w.(http.Pusher); ok {
+		id += pusher
+	}
+
+	return pickDelegator[id](d)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go

@@ -1,181 +0,0 @@
-// Copyright 2017 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build go1.8
-
-package promhttp
-
-import (
-	"io"
-	"net/http"
-)
-
-type pusherDelegator struct{ *responseWriterDelegator }
-
-func (d *pusherDelegator) Push(target string, opts *http.PushOptions) error {
-	return d.ResponseWriter.(http.Pusher).Push(target, opts)
-}
-
-func init() {
-	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
-		return pusherDelegator{d}
-	}
-	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Flusher
-		}{d, &pusherDelegator{d}, &flusherDelegator{d}}
-	}
-	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Flusher
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-		}{d, &pusherDelegator{d}, &hijackerDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.Flusher
-		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.Flusher
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Flusher
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Flusher
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.Flusher
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.Flusher
-			http.CloseNotifier
-		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
-	}
-}
-
-func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
-	d := &responseWriterDelegator{
-		ResponseWriter:     w,
-		observeWriteHeader: observeWriteHeaderFunc,
-	}
-
-	id := 0
-	if _, ok := w.(http.CloseNotifier); ok {
-		id += closeNotifier
-	}
-	if _, ok := w.(http.Flusher); ok {
-		id += flusher
-	}
-	if _, ok := w.(http.Hijacker); ok {
-		id += hijacker
-	}
-	if _, ok := w.(io.ReaderFrom); ok {
-		id += readerFrom
-	}
-	if _, ok := w.(http.Pusher); ok {
-		id += pusher
-	}
-
-	return pickDelegator[id](d)
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_pre_1_8.go

@@ -1,44 +0,0 @@
-// Copyright 2017 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build !go1.8
-
-package promhttp
-
-import (
-	"io"
-	"net/http"
-)
-
-func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
-	d := &responseWriterDelegator{
-		ResponseWriter:     w,
-		observeWriteHeader: observeWriteHeaderFunc,
-	}
-
-	id := 0
-	if _, ok := w.(http.CloseNotifier); ok {
-		id += closeNotifier
-	}
-	if _, ok := w.(http.Flusher); ok {
-		id += flusher
-	}
-	if _, ok := w.(http.Hijacker); ok {
-		id += hijacker
-	}
-	if _, ok := w.(io.ReaderFrom); ok {
-		id += readerFrom
-	}
-
-	return pickDelegator[id](d)
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -32,13 +32,13 @@
 package promhttp
 
 import (
-	"bytes"
 	"compress/gzip"
 	"fmt"
 	"io"
 	"net/http"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/prometheus/common/expfmt"
 
@@ -47,99 +47,204 @@ import (
 
 const (
 	contentTypeHeader     = "Content-Type"
-	contentLengthHeader   = "Content-Length"
 	contentEncodingHeader = "Content-Encoding"
 	acceptEncodingHeader  = "Accept-Encoding"
 )
 
-var bufPool sync.Pool
-
-func getBuf() *bytes.Buffer {
-	buf := bufPool.Get()
-	if buf == nil {
-		return &bytes.Buffer{}
-	}
-	return buf.(*bytes.Buffer)
+var gzipPool = sync.Pool{
+	New: func() interface{} {
+		return gzip.NewWriter(nil)
+	},
 }
 
-func giveBuf(buf *bytes.Buffer) {
-	buf.Reset()
-	bufPool.Put(buf)
-}
-
-// Handler returns an HTTP handler for the prometheus.DefaultGatherer. The
-// Handler uses the default HandlerOpts, i.e. report the first error as an HTTP
-// error, no error logging, and compression if requested by the client.
+// Handler returns an http.Handler for the prometheus.DefaultGatherer, using
+// default HandlerOpts, i.e. it reports the first error as an HTTP error, it has
+// no error logging, and it applies compression if requested by the client.
 //
-// If you want to create a Handler for the DefaultGatherer with different
-// HandlerOpts, create it with HandlerFor with prometheus.DefaultGatherer and
-// your desired HandlerOpts.
+// The returned http.Handler is already instrumented using the
+// InstrumentMetricHandler function and the prometheus.DefaultRegisterer. If you
+// create multiple http.Handlers by separate calls of the Handler function, the
+// metrics used for instrumentation will be shared between them, providing
+// global scrape counts.
+//
+// This function is meant to cover the bulk of basic use cases. If you are doing
+// anything that requires more customization (including using a non-default
+// Gatherer, different instrumentation, and non-default HandlerOpts), use the
+// HandlerFor function. See there for details.
 func Handler() http.Handler {
-	return HandlerFor(prometheus.DefaultGatherer, HandlerOpts{})
+	return InstrumentMetricHandler(
+		prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
+	)
 }
 
-// HandlerFor returns an http.Handler for the provided Gatherer. The behavior
-// of the Handler is defined by the provided HandlerOpts.
+// HandlerFor returns an uninstrumented http.Handler for the provided
+// Gatherer. The behavior of the Handler is defined by the provided
+// HandlerOpts. Thus, HandlerFor is useful to create http.Handlers for custom
+// Gatherers, with non-default HandlerOpts, and/or with custom (or no)
+// instrumentation. Use the InstrumentMetricHandler function to apply the same
+// kind of instrumentation as it is used by the Handler function.
 func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+	var (
+		inFlightSem chan struct{}
+		errCnt      = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "promhttp_metric_handler_errors_total",
+				Help: "Total number of internal errors encountered by the promhttp metric handler.",
+			},
+			[]string{"cause"},
+		)
+	)
+
+	if opts.MaxRequestsInFlight > 0 {
+		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
+	}
+	if opts.Registry != nil {
+		// Initialize all possibilites that can occur below.
+		errCnt.WithLabelValues("gathering")
+		errCnt.WithLabelValues("encoding")
+		if err := opts.Registry.Register(errCnt); err != nil {
+			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
+			} else {
+				panic(err)
+			}
+		}
+	}
+
+	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
+		if inFlightSem != nil {
+			select {
+			case inFlightSem <- struct{}{}: // All good, carry on.
+				defer func() { <-inFlightSem }()
+			default:
+				http.Error(rsp, fmt.Sprintf(
+					"Limit of concurrent requests reached (%d), try again later.", opts.MaxRequestsInFlight,
+				), http.StatusServiceUnavailable)
+				return
+			}
+		}
 		mfs, err := reg.Gather()
 		if err != nil {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error gathering metrics:", err)
 			}
+			errCnt.WithLabelValues("gathering").Inc()
 			switch opts.ErrorHandling {
 			case PanicOnError:
 				panic(err)
 			case ContinueOnError:
 				if len(mfs) == 0 {
-					http.Error(w, "No metrics gathered, last error:\n\n"+err.Error(), http.StatusInternalServerError)
+					// Still report the error if no metrics have been gathered.
+					httpError(rsp, err)
 					return
 				}
 			case HTTPErrorOnError:
-				http.Error(w, "An error has occurred during metrics gathering:\n\n"+err.Error(), http.StatusInternalServerError)
+				httpError(rsp, err)
 				return
 			}
 		}
 
 		contentType := expfmt.Negotiate(req.Header)
-		buf := getBuf()
-		defer giveBuf(buf)
-		writer, encoding := decorateWriter(req, buf, opts.DisableCompression)
-		enc := expfmt.NewEncoder(writer, contentType)
+		header := rsp.Header()
+		header.Set(contentTypeHeader, string(contentType))
+
+		w := io.Writer(rsp)
+		if !opts.DisableCompression && gzipAccepted(req.Header) {
+			header.Set(contentEncodingHeader, "gzip")
+			gz := gzipPool.Get().(*gzip.Writer)
+			defer gzipPool.Put(gz)
+
+			gz.Reset(w)
+			defer gz.Close()
+
+			w = gz
+		}
+
+		enc := expfmt.NewEncoder(w, contentType)
+
 		var lastErr error
 		for _, mf := range mfs {
 			if err := enc.Encode(mf); err != nil {
 				lastErr = err
 				if opts.ErrorLog != nil {
-					opts.ErrorLog.Println("error encoding metric family:", err)
+					opts.ErrorLog.Println("error encoding and sending metric family:", err)
 				}
+				errCnt.WithLabelValues("encoding").Inc()
 				switch opts.ErrorHandling {
 				case PanicOnError:
 					panic(err)
 				case ContinueOnError:
 					// Handled later.
 				case HTTPErrorOnError:
-					http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
+					httpError(rsp, err)
 					return
 				}
 			}
 		}
-		if closer, ok := writer.(io.Closer); ok {
-			closer.Close()
+
+		if lastErr != nil {
+			httpError(rsp, lastErr)
 		}
-		if lastErr != nil && buf.Len() == 0 {
-			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
-			return
-		}
-		header := w.Header()
-		header.Set(contentTypeHeader, string(contentType))
-		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
-		if encoding != "" {
-			header.Set(contentEncodingHeader, encoding)
-		}
-		w.Write(buf.Bytes())
-		// TODO(beorn7): Consider streaming serving of metrics.
 	})
+
+	if opts.Timeout <= 0 {
+		return h
+	}
+	return http.TimeoutHandler(h, opts.Timeout, fmt.Sprintf(
+		"Exceeded configured timeout of %v.\n",
+		opts.Timeout,
+	))
+}
+
+// InstrumentMetricHandler is usually used with an http.Handler returned by the
+// HandlerFor function. It instruments the provided http.Handler with two
+// metrics: A counter vector "promhttp_metric_handler_requests_total" to count
+// scrapes partitioned by HTTP status code, and a gauge
+// "promhttp_metric_handler_requests_in_flight" to track the number of
+// simultaneous scrapes. This function idempotently registers collectors for
+// both metrics with the provided Registerer. It panics if the registration
+// fails. The provided metrics are useful to see how many scrapes hit the
+// monitored target (which could be from different Prometheus servers or other
+// scrapers), and how often they overlap (which would result in more than one
+// scrape in flight at the same time). Note that the scrapes-in-flight gauge
+// will contain the scrape by which it is exposed, while the scrape counter will
+// only get incremented after the scrape is complete (as only then the status
+// code is known). For tracking scrape durations, use the
+// "scrape_duration_seconds" gauge created by the Prometheus server upon each
+// scrape.
+func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) http.Handler {
+	cnt := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "promhttp_metric_handler_requests_total",
+			Help: "Total number of scrapes by HTTP status code.",
+		},
+		[]string{"code"},
+	)
+	// Initialize the most likely HTTP status codes.
+	cnt.WithLabelValues("200")
+	cnt.WithLabelValues("500")
+	cnt.WithLabelValues("503")
+	if err := reg.Register(cnt); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			cnt = are.ExistingCollector.(*prometheus.CounterVec)
+		} else {
+			panic(err)
+		}
+	}
+
+	gge := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "promhttp_metric_handler_requests_in_flight",
+		Help: "Current number of scrapes being served.",
+	})
+	if err := reg.Register(gge); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			gge = are.ExistingCollector.(prometheus.Gauge)
+		} else {
+			panic(err)
+		}
+	}
+
+	return InstrumentHandlerCounter(cnt, InstrumentHandlerInFlight(gge, handler))
 }
 
 // HandlerErrorHandling defines how a Handler serving metrics will handle
@@ -155,9 +260,12 @@ const (
 	// Ignore errors and try to serve as many metrics as possible.  However,
 	// if no metrics can be served, serve an HTTP status code 500 and the
 	// last error message in the body. Only use this in deliberate "best
-	// effort" metrics collection scenarios. It is recommended to at least
-	// log errors (by providing an ErrorLog in HandlerOpts) to not mask
-	// errors completely.
+	// effort" metrics collection scenarios. In this case, it is highly
+	// recommended to provide other means of detecting errors: By setting an
+	// ErrorLog in HandlerOpts, the errors are logged. By providing a
+	// Registry in HandlerOpts, the exposed metrics include an error counter
+	// "promhttp_metric_handler_errors_total", which can be used for
+	// alerts.
 	ContinueOnError
 	// Panic upon the first error encountered (useful for "crash only" apps).
 	PanicOnError
@@ -180,25 +288,62 @@ type HandlerOpts struct {
 	// logged regardless of the configured ErrorHandling provided ErrorLog
 	// is not nil.
 	ErrorHandling HandlerErrorHandling
+	// If Registry is not nil, it is used to register a metric
+	// "promhttp_metric_handler_errors_total", partitioned by "cause". A
+	// failed registration causes a panic. Note that this error counter is
+	// different from the instrumentation you get from the various
+	// InstrumentHandler... helpers. It counts errors that don't necessarily
+	// result in a non-2xx HTTP status code. There are two typical cases:
+	// (1) Encoding errors that only happen after streaming of the HTTP body
+	// has already started (and the status code 200 has been sent). This
+	// should only happen with custom collectors. (2) Collection errors with
+	// no effect on the HTTP status code because ErrorHandling is set to
+	// ContinueOnError.
+	Registry prometheus.Registerer
 	// If DisableCompression is true, the handler will never compress the
 	// response, even if requested by the client.
 	DisableCompression bool
+	// The number of concurrent HTTP requests is limited to
+	// MaxRequestsInFlight. Additional requests are responded to with 503
+	// Service Unavailable and a suitable message in the body. If
+	// MaxRequestsInFlight is 0 or negative, no limit is applied.
+	MaxRequestsInFlight int
+	// If handling a request takes longer than Timeout, it is responded to
+	// with 503 ServiceUnavailable and a suitable Message. No timeout is
+	// applied if Timeout is 0 or negative. Note that with the current
+	// implementation, reaching the timeout simply ends the HTTP requests as
+	// described above (and even that only if sending of the body hasn't
+	// started yet), while the bulk work of gathering all the metrics keeps
+	// running in the background (with the eventual result to be thrown
+	// away). Until the implementation is improved, it is recommended to
+	// implement a separate timeout in potentially slow Collectors.
+	Timeout time.Duration
 }
 
-// decorateWriter wraps a writer to handle gzip compression if requested.  It
-// returns the decorated writer and the appropriate "Content-Encoding" header
-// (which is empty if no compression is enabled).
-func decorateWriter(request *http.Request, writer io.Writer, compressionDisabled bool) (io.Writer, string) {
-	if compressionDisabled {
-		return writer, ""
-	}
-	header := request.Header.Get(acceptEncodingHeader)
-	parts := strings.Split(header, ",")
+// gzipAccepted returns whether the client will accept gzip-encoded content.
+func gzipAccepted(header http.Header) bool {
+	a := header.Get(acceptEncodingHeader)
+	parts := strings.Split(a, ",")
 	for _, part := range parts {
-		part := strings.TrimSpace(part)
+		part = strings.TrimSpace(part)
 		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return gzip.NewWriter(writer), "gzip"
+			return true
 		}
 	}
-	return writer, ""
+	return false
+}
+
+// httpError removes any content-encoding header and then calls http.Error with
+// the provided error and http.StatusInternalServerErrer. Error contents is
+// supposed to be uncompressed plain text. However, same as with a plain
+// http.Error, any header settings will be void if the header has already been
+// sent. The error message will still be written to the writer, but it will
+// probably be of limited use.
+func httpError(rsp http.ResponseWriter, err error) {
+	rsp.Header().Del(contentEncodingHeader)
+	http.Error(
+		rsp,
+		"An error has occurred while serving metrics:\n\n"+err.Error(),
+		http.StatusInternalServerError,
+	)
 }

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go

@@ -14,7 +14,9 @@
 package promhttp
 
 import (
+	"crypto/tls"
 	"net/http"
+	"net/http/httptrace"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -45,12 +47,11 @@ func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripp
 
 // InstrumentRoundTripperCounter is a middleware that wraps the provided
 // http.RoundTripper to observe the request result with the provided CounterVec.
-// The CounterVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. Partitioning of the CounterVec happens by HTTP status
-// code and/or HTTP method if the respective instance label names are present
-// in the CounterVec. For unpartitioned counting, use a CounterVec with
-// zero labels.
+// The CounterVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. Partitioning of the CounterVec happens by HTTP status code
+// and/or HTTP method if the respective instance label names are present in the
+// CounterVec. For unpartitioned counting, use a CounterVec with zero labels.
 //
 // If the wrapped RoundTripper panics or returns a non-nil error, the Counter
 // is not incremented.
@@ -69,15 +70,15 @@ func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.Rou
 }
 
 // InstrumentRoundTripperDuration is a middleware that wraps the provided
-// http.RoundTripper to observe the request duration with the provided ObserverVec.
-// The ObserverVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. The Observe method of the Observer in the ObserverVec
-// is called with the request duration in seconds. Partitioning happens by HTTP
-// status code and/or HTTP method if the respective instance label names are
-// present in the ObserverVec. For unpartitioned observations, use an
-// ObserverVec with zero labels. Note that partitioning of Histograms is
-// expensive and should be used judiciously.
+// http.RoundTripper to observe the request duration with the provided
+// ObserverVec.  The ObserverVec must have zero, one, or two non-const
+// non-curried labels. For those, the only allowed label names are "code" and
+// "method". The function panics otherwise. The Observe method of the Observer
+// in the ObserverVec is called with the request duration in
+// seconds. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
 //
 // If the wrapped RoundTripper panics or returns a non-nil error, no values are
 // reported.
@@ -96,3 +97,123 @@ func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundT
 		return resp, err
 	})
 }
+
+// InstrumentTrace is used to offer flexibility in instrumenting the available
+// httptrace.ClientTrace hook functions. Each function is passed a float64
+// representing the time in seconds since the start of the http request. A user
+// may choose to use separately buckets Histograms, or implement custom
+// instance labels on a per function basis.
+type InstrumentTrace struct {
+	GotConn              func(float64)
+	PutIdleConn          func(float64)
+	GotFirstResponseByte func(float64)
+	Got100Continue       func(float64)
+	DNSStart             func(float64)
+	DNSDone              func(float64)
+	ConnectStart         func(float64)
+	ConnectDone          func(float64)
+	TLSHandshakeStart    func(float64)
+	TLSHandshakeDone     func(float64)
+	WroteHeaders         func(float64)
+	Wait100Continue      func(float64)
+	WroteRequest         func(float64)
+}
+
+// InstrumentRoundTripperTrace is a middleware that wraps the provided
+// RoundTripper and reports times to hook functions provided in the
+// InstrumentTrace struct. Hook functions that are not present in the provided
+// InstrumentTrace struct are ignored. Times reported to the hook functions are
+// time since the start of the request. Only with Go1.9+, those times are
+// guaranteed to never be negative. (Earlier Go versions are not using a
+// monotonic clock.) Note that partitioning of Histograms is expensive and
+// should be used judiciously.
+//
+// For hook functions that receive an error as an argument, no observations are
+// made in the event of a non-nil error value.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+
+		trace := &httptrace.ClientTrace{
+			GotConn: func(_ httptrace.GotConnInfo) {
+				if it.GotConn != nil {
+					it.GotConn(time.Since(start).Seconds())
+				}
+			},
+			PutIdleConn: func(err error) {
+				if err != nil {
+					return
+				}
+				if it.PutIdleConn != nil {
+					it.PutIdleConn(time.Since(start).Seconds())
+				}
+			},
+			DNSStart: func(_ httptrace.DNSStartInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			DNSDone: func(_ httptrace.DNSDoneInfo) {
+				if it.DNSDone != nil {
+					it.DNSDone(time.Since(start).Seconds())
+				}
+			},
+			ConnectStart: func(_, _ string) {
+				if it.ConnectStart != nil {
+					it.ConnectStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectDone: func(_, _ string, err error) {
+				if err != nil {
+					return
+				}
+				if it.ConnectDone != nil {
+					it.ConnectDone(time.Since(start).Seconds())
+				}
+			},
+			GotFirstResponseByte: func() {
+				if it.GotFirstResponseByte != nil {
+					it.GotFirstResponseByte(time.Since(start).Seconds())
+				}
+			},
+			Got100Continue: func() {
+				if it.Got100Continue != nil {
+					it.Got100Continue(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeStart: func() {
+				if it.TLSHandshakeStart != nil {
+					it.TLSHandshakeStart(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
+				if err != nil {
+					return
+				}
+				if it.TLSHandshakeDone != nil {
+					it.TLSHandshakeDone(time.Since(start).Seconds())
+				}
+			},
+			WroteHeaders: func() {
+				if it.WroteHeaders != nil {
+					it.WroteHeaders(time.Since(start).Seconds())
+				}
+			},
+			Wait100Continue: func() {
+				if it.Wait100Continue != nil {
+					it.Wait100Continue(time.Since(start).Seconds())
+				}
+			},
+			WroteRequest: func(_ httptrace.WroteRequestInfo) {
+				if it.WroteRequest != nil {
+					it.WroteRequest(time.Since(start).Seconds())
+				}
+			},
+		}
+		r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
+
+		return next.RoundTrip(r)
+	})
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client_1_8.go

@@ -1,144 +0,0 @@
-// Copyright 2017 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build go1.8
-
-package promhttp
-
-import (
-	"context"
-	"crypto/tls"
-	"net/http"
-	"net/http/httptrace"
-	"time"
-)
-
-// InstrumentTrace is used to offer flexibility in instrumenting the available
-// httptrace.ClientTrace hook functions. Each function is passed a float64
-// representing the time in seconds since the start of the http request. A user
-// may choose to use separately buckets Histograms, or implement custom
-// instance labels on a per function basis.
-type InstrumentTrace struct {
-	GotConn              func(float64)
-	PutIdleConn          func(float64)
-	GotFirstResponseByte func(float64)
-	Got100Continue       func(float64)
-	DNSStart             func(float64)
-	DNSDone              func(float64)
-	ConnectStart         func(float64)
-	ConnectDone          func(float64)
-	TLSHandshakeStart    func(float64)
-	TLSHandshakeDone     func(float64)
-	WroteHeaders         func(float64)
-	Wait100Continue      func(float64)
-	WroteRequest         func(float64)
-}
-
-// InstrumentRoundTripperTrace is a middleware that wraps the provided
-// RoundTripper and reports times to hook functions provided in the
-// InstrumentTrace struct. Hook functions that are not present in the provided
-// InstrumentTrace struct are ignored. Times reported to the hook functions are
-// time since the start of the request. Only with Go1.9+, those times are
-// guaranteed to never be negative. (Earlier Go versions are not using a
-// monotonic clock.) Note that partitioning of Histograms is expensive and
-// should be used judiciously.
-//
-// For hook functions that receive an error as an argument, no observations are
-// made in the event of a non-nil error value.
-//
-// See the example for ExampleInstrumentRoundTripperDuration for example usage.
-func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
-	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
-		start := time.Now()
-
-		trace := &httptrace.ClientTrace{
-			GotConn: func(_ httptrace.GotConnInfo) {
-				if it.GotConn != nil {
-					it.GotConn(time.Since(start).Seconds())
-				}
-			},
-			PutIdleConn: func(err error) {
-				if err != nil {
-					return
-				}
-				if it.PutIdleConn != nil {
-					it.PutIdleConn(time.Since(start).Seconds())
-				}
-			},
-			DNSStart: func(_ httptrace.DNSStartInfo) {
-				if it.DNSStart != nil {
-					it.DNSStart(time.Since(start).Seconds())
-				}
-			},
-			DNSDone: func(_ httptrace.DNSDoneInfo) {
-				if it.DNSStart != nil {
-					it.DNSStart(time.Since(start).Seconds())
-				}
-			},
-			ConnectStart: func(_, _ string) {
-				if it.ConnectStart != nil {
-					it.ConnectStart(time.Since(start).Seconds())
-				}
-			},
-			ConnectDone: func(_, _ string, err error) {
-				if err != nil {
-					return
-				}
-				if it.ConnectDone != nil {
-					it.ConnectDone(time.Since(start).Seconds())
-				}
-			},
-			GotFirstResponseByte: func() {
-				if it.GotFirstResponseByte != nil {
-					it.GotFirstResponseByte(time.Since(start).Seconds())
-				}
-			},
-			Got100Continue: func() {
-				if it.Got100Continue != nil {
-					it.Got100Continue(time.Since(start).Seconds())
-				}
-			},
-			TLSHandshakeStart: func() {
-				if it.TLSHandshakeStart != nil {
-					it.TLSHandshakeStart(time.Since(start).Seconds())
-				}
-			},
-			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
-				if err != nil {
-					return
-				}
-				if it.TLSHandshakeDone != nil {
-					it.TLSHandshakeDone(time.Since(start).Seconds())
-				}
-			},
-			WroteHeaders: func() {
-				if it.WroteHeaders != nil {
-					it.WroteHeaders(time.Since(start).Seconds())
-				}
-			},
-			Wait100Continue: func() {
-				if it.Wait100Continue != nil {
-					it.Wait100Continue(time.Since(start).Seconds())
-				}
-			},
-			WroteRequest: func(_ httptrace.WroteRequestInfo) {
-				if it.WroteRequest != nil {
-					it.WroteRequest(time.Since(start).Seconds())
-				}
-			},
-		}
-		r = r.WithContext(httptrace.WithClientTrace(context.Background(), trace))
-
-		return next.RoundTrip(r)
-	})
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go

@@ -14,6 +14,7 @@
 package promhttp
 
 import (
+	"errors"
 	"net/http"
 	"strconv"
 	"strings"
@@ -42,10 +43,10 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl
 
 // InstrumentHandlerDuration is a middleware that wraps the provided
 // http.Handler to observe the request duration with the provided ObserverVec.
-// The ObserverVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. The Observe method of the Observer in the ObserverVec
-// is called with the request duration in seconds. Partitioning happens by HTTP
+// The ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the request duration in seconds. Partitioning happens by HTTP
 // status code and/or HTTP method if the respective instance label names are
 // present in the ObserverVec. For unpartitioned observations, use an
 // ObserverVec with zero labels. Note that partitioning of Histograms is
@@ -77,14 +78,13 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) ht
 	})
 }
 
-// InstrumentHandlerCounter is a middleware that wraps the provided
-// http.Handler to observe the request result with the provided CounterVec.
-// The CounterVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. Partitioning of the CounterVec happens by HTTP status
-// code and/or HTTP method if the respective instance label names are present
-// in the CounterVec. For unpartitioned counting, use a CounterVec with
-// zero labels.
+// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler
+// to observe the request result with the provided CounterVec.  The CounterVec
+// must have zero, one, or two non-const non-curried labels. For those, the only
+// allowed label names are "code" and "method". The function panics
+// otherwise. Partitioning of the CounterVec happens by HTTP status code and/or
+// HTTP method if the respective instance label names are present in the
+// CounterVec. For unpartitioned counting, use a CounterVec with zero labels.
 //
 // If the wrapped Handler does not set a status code, a status code of 200 is assumed.
 //
@@ -111,14 +111,13 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler)
 // InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
 // http.Handler to observe with the provided ObserverVec the request duration
 // until the response headers are written. The ObserverVec must have zero, one,
-// or two labels. The only allowed label names are "code" and "method". The
-// function panics if any other instance labels are provided. The Observe
-// method of the Observer in the ObserverVec is called with the request
-// duration in seconds. Partitioning happens by HTTP status code and/or HTTP
-// method if the respective instance label names are present in the
-// ObserverVec. For unpartitioned observations, use an ObserverVec with zero
-// labels. Note that partitioning of Histograms is expensive and should be used
-// judiciously.
+// or two non-const non-curried labels. For those, the only allowed label names
+// are "code" and "method". The function panics otherwise. The Observe method of
+// the Observer in the ObserverVec is called with the request duration in
+// seconds. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
 //
 // If the wrapped Handler panics before calling WriteHeader, no value is
 // reported.
@@ -140,15 +139,15 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha
 }
 
 // InstrumentHandlerRequestSize is a middleware that wraps the provided
-// http.Handler to observe the request size with the provided ObserverVec.
-// The ObserverVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. The Observe method of the Observer in the ObserverVec
-// is called with the request size in bytes. Partitioning happens by HTTP
-// status code and/or HTTP method if the respective instance label names are
-// present in the ObserverVec. For unpartitioned observations, use an
-// ObserverVec with zero labels. Note that partitioning of Histograms is
-// expensive and should be used judiciously.
+// http.Handler to observe the request size with the provided ObserverVec.  The
+// ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the request size in bytes. Partitioning happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present in
+// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero
+// labels. Note that partitioning of Histograms is expensive and should be used
+// judiciously.
 //
 // If the wrapped Handler does not set a status code, a status code of 200 is assumed.
 //
@@ -175,15 +174,15 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler)
 }
 
 // InstrumentHandlerResponseSize is a middleware that wraps the provided
-// http.Handler to observe the response size with the provided ObserverVec.
-// The ObserverVec must have zero, one, or two labels. The only allowed label
-// names are "code" and "method". The function panics if any other instance
-// labels are provided. The Observe method of the Observer in the ObserverVec
-// is called with the response size in bytes. Partitioning happens by HTTP
-// status code and/or HTTP method if the respective instance label names are
-// present in the ObserverVec. For unpartitioned observations, use an
-// ObserverVec with zero labels. Note that partitioning of Histograms is
-// expensive and should be used judiciously.
+// http.Handler to observe the response size with the provided ObserverVec.  The
+// ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the response size in bytes. Partitioning happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present in
+// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero
+// labels. Note that partitioning of Histograms is expensive and should be used
+// judiciously.
 //
 // If the wrapped Handler does not set a status code, a status code of 200 is assumed.
 //
@@ -204,9 +203,12 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) {
 	// once Descriptors can have their dimensionality queried.
 	var (
 		desc *prometheus.Desc
+		m    prometheus.Metric
 		pm   dto.Metric
+		lvs  []string
 	)
 
+	// Get the Desc from the Collector.
 	descc := make(chan *prometheus.Desc, 1)
 	c.Describe(descc)
 
@@ -223,49 +225,54 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) {
 
 	close(descc)
 
-	if _, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0); err == nil {
-		return
+	// Create a ConstMetric with the Desc. Since we don't know how many
+	// variable labels there are, try for as long as it needs.
+	for err := errors.New("dummy"); err != nil; lvs = append(lvs, magicString) {
+		m, err = prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, lvs...)
 	}
-	if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString); err == nil {
-		if err := m.Write(&pm); err != nil {
-			panic("error checking metric for labels")
-		}
-		for _, label := range pm.Label {
-			name, value := label.GetName(), label.GetValue()
-			if value != magicString {
-				continue
-			}
-			switch name {
-			case "code":
-				code = true
-			case "method":
-				method = true
-			default:
-				panic("metric partitioned with non-supported labels")
-			}
-			return
-		}
-		panic("previously set label not found – this must never happen")
+
+	// Write out the metric into a proto message and look at the labels.
+	// If the value is not the magicString, it is a constLabel, which doesn't interest us.
+	// If the label is curried, it doesn't interest us.
+	// In all other cases, only "code" or "method" is allowed.
+	if err := m.Write(&pm); err != nil {
+		panic("error checking metric for labels")
 	}
-	if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString, magicString); err == nil {
-		if err := m.Write(&pm); err != nil {
-			panic("error checking metric for labels")
+	for _, label := range pm.Label {
+		name, value := label.GetName(), label.GetValue()
+		if value != magicString || isLabelCurried(c, name) {
+			continue
 		}
-		for _, label := range pm.Label {
-			name, value := label.GetName(), label.GetValue()
-			if value != magicString {
-				continue
-			}
-			if name == "code" || name == "method" {
-				continue
-			}
+		switch name {
+		case "code":
+			code = true
+		case "method":
+			method = true
+		default:
 			panic("metric partitioned with non-supported labels")
 		}
-		code = true
-		method = true
-		return
 	}
-	panic("metric partitioned with non-supported labels")
+	return
+}
+
+func isLabelCurried(c prometheus.Collector, label string) bool {
+	// This is even hackier than the label test above.
+	// We essentially try to curry again and see if it works.
+	// But for that, we need to type-convert to the two
+	// types we use here, ObserverVec or *CounterVec.
+	switch v := c.(type) {
+	case *prometheus.CounterVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	case prometheus.ObserverVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	default:
+		panic("unsupported metric vec type")
+	}
+	return true
 }
 
 // emptyLabels is a one-time allocation for non-partitioned metrics to avoid

vendor/github.com/prometheus/client_golang/prometheus/registry.go

@@ -15,16 +15,22 @@ package prometheus
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
+	"io/ioutil"
 	"os"
+	"path/filepath"
+	"runtime"
 	"sort"
+	"strings"
 	"sync"
 	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/expfmt"
 
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus/internal"
 )
 
 const (
@@ -36,13 +42,14 @@ const (
 // DefaultRegisterer and DefaultGatherer are the implementations of the
 // Registerer and Gatherer interface a number of convenience functions in this
 // package act on. Initially, both variables point to the same Registry, which
-// has a process collector (see NewProcessCollector) and a Go collector (see
-// NewGoCollector) already registered. This approach to keep default instances
-// as global state mirrors the approach of other packages in the Go standard
-// library. Note that there are caveats. Change the variables with caution and
-// only if you understand the consequences. Users who want to avoid global state
-// altogether should not use the convenience function and act on custom
-// instances instead.
+// has a process collector (currently on Linux only, see NewProcessCollector)
+// and a Go collector (see NewGoCollector, in particular the note about
+// stop-the-world implication with Go versions older than 1.9) already
+// registered. This approach to keep default instances as global state mirrors
+// the approach of other packages in the Go standard library. Note that there
+// are caveats. Change the variables with caution and only if you understand the
+// consequences. Users who want to avoid global state altogether should not use
+// the convenience functions and act on custom instances instead.
 var (
 	defaultRegistry              = NewRegistry()
 	DefaultRegisterer Registerer = defaultRegistry
@@ -50,7 +57,7 @@ var (
 )
 
 func init() {
-	MustRegister(NewProcessCollector(os.Getpid(), ""))
+	MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
 	MustRegister(NewGoCollector())
 }
 
@@ -66,7 +73,8 @@ func NewRegistry() *Registry {
 
 // NewPedanticRegistry returns a registry that checks during collection if each
 // collected Metric is consistent with its reported Desc, and if the Desc has
-// actually been registered with the registry.
+// actually been registered with the registry. Unchecked Collectors (those whose
+// Describe methed does not yield any descriptors) are excluded from the check.
 //
 // Usually, a Registry will be happy as long as the union of all collected
 // Metrics is consistent and valid even if some metrics are not consistent with
@@ -96,8 +104,13 @@ type Registerer interface {
 	// returned error is an instance of AlreadyRegisteredError, which
 	// contains the previously registered Collector.
 	//
-	// It is in general not safe to register the same Collector multiple
-	// times concurrently.
+	// A Collector whose Describe method does not yield any Desc is treated
+	// as unchecked. Registration will always succeed. No check for
+	// re-registering (see previous paragraph) is performed. Thus, the
+	// caller is responsible for not double-registering the same unchecked
+	// Collector, and for providing a Collector that will not cause
+	// inconsistent metrics on collection. (This would lead to scrape
+	// errors.)
 	Register(Collector) error
 	// MustRegister works like Register but registers any number of
 	// Collectors and panics upon the first registration that causes an
@@ -106,7 +119,9 @@ type Registerer interface {
 	// Unregister unregisters the Collector that equals the Collector passed
 	// in as an argument.  (Two Collectors are considered equal if their
 	// Describe method yields the same set of descriptors.) The function
-	// returns whether a Collector was unregistered.
+	// returns whether a Collector was unregistered. Note that an unchecked
+	// Collector cannot be unregistered (as its Describe method does not
+	// yield any descriptor).
 	//
 	// Note that even after unregistering, it will not be possible to
 	// register a new Collector that is inconsistent with the unregistered
@@ -124,15 +139,23 @@ type Registerer interface {
 type Gatherer interface {
 	// Gather calls the Collect method of the registered Collectors and then
 	// gathers the collected metrics into a lexicographically sorted slice
-	// of MetricFamily protobufs. Even if an error occurs, Gather attempts
-	// to gather as many metrics as possible. Hence, if a non-nil error is
-	// returned, the returned MetricFamily slice could be nil (in case of a
-	// fatal error that prevented any meaningful metric collection) or
-	// contain a number of MetricFamily protobufs, some of which might be
-	// incomplete, and some might be missing altogether. The returned error
-	// (which might be a MultiError) explains the details. In scenarios
-	// where complete collection is critical, the returned MetricFamily
-	// protobufs should be disregarded if the returned error is non-nil.
+	// of uniquely named MetricFamily protobufs. Gather ensures that the
+	// returned slice is valid and self-consistent so that it can be used
+	// for valid exposition. As an exception to the strict consistency
+	// requirements described for metric.Desc, Gather will tolerate
+	// different sets of label names for metrics of the same metric family.
+	//
+	// Even if an error occurs, Gather attempts to gather as many metrics as
+	// possible. Hence, if a non-nil error is returned, the returned
+	// MetricFamily slice could be nil (in case of a fatal error that
+	// prevented any meaningful metric collection) or contain a number of
+	// MetricFamily protobufs, some of which might be incomplete, and some
+	// might be missing altogether. The returned error (which might be a
+	// MultiError) explains the details. Note that this is mostly useful for
+	// debugging purposes. If the gathered protobufs are to be used for
+	// exposition in actual monitoring, it is almost always better to not
+	// expose an incomplete result and instead disregard the returned
+	// MetricFamily protobufs in case the returned error is non-nil.
 	Gather() ([]*dto.MetricFamily, error)
 }
 
@@ -202,6 +225,13 @@ func (errs MultiError) Error() string {
 	return buf.String()
 }
 
+// Append appends the provided error if it is not nil.
+func (errs *MultiError) Append(err error) {
+	if err != nil {
+		*errs = append(*errs, err)
+	}
+}
+
 // MaybeUnwrap returns nil if len(errs) is 0. It returns the first and only
 // contained error as error if len(errs is 1). In all other cases, it returns
 // the MultiError directly. This is helpful for returning a MultiError in a way
@@ -226,6 +256,7 @@ type Registry struct {
 	collectorsByID        map[uint64]Collector // ID is a hash of the descIDs.
 	descIDs               map[uint64]struct{}
 	dimHashesByName       map[string]uint64
+	uncheckedCollectors   []Collector
 	pedanticChecksEnabled bool
 }
 
@@ -243,7 +274,12 @@ func (r *Registry) Register(c Collector) error {
 		close(descChan)
 	}()
 	r.mtx.Lock()
-	defer r.mtx.Unlock()
+	defer func() {
+		// Drain channel in case of premature return to not leak a goroutine.
+		for range descChan {
+		}
+		r.mtx.Unlock()
+	}()
 	// Conduct various tests...
 	for desc := range descChan {
 
@@ -283,9 +319,10 @@ func (r *Registry) Register(c Collector) error {
 			}
 		}
 	}
-	// Did anything happen at all?
+	// A Collector yielding no Desc at all is considered unchecked.
 	if len(newDescIDs) == 0 {
-		return errors.New("collector has no descriptors")
+		r.uncheckedCollectors = append(r.uncheckedCollectors, c)
+		return nil
 	}
 	if existing, exists := r.collectorsByID[collectorID]; exists {
 		return AlreadyRegisteredError{
@@ -359,31 +396,25 @@ func (r *Registry) MustRegister(cs ...Collector) {
 // Gather implements Gatherer.
 func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	var (
-		metricChan        = make(chan Metric, capMetricChan)
-		metricHashes      = map[uint64]struct{}{}
-		dimHashes         = map[string]uint64{}
-		wg                sync.WaitGroup
-		errs              MultiError          // The collected errors to return in the end.
-		registeredDescIDs map[uint64]struct{} // Only used for pedantic checks
+		checkedMetricChan   = make(chan Metric, capMetricChan)
+		uncheckedMetricChan = make(chan Metric, capMetricChan)
+		metricHashes        = map[uint64]struct{}{}
+		wg                  sync.WaitGroup
+		errs                MultiError          // The collected errors to return in the end.
+		registeredDescIDs   map[uint64]struct{} // Only used for pedantic checks
 	)
 
 	r.mtx.RLock()
+	goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
 	metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
-
-	// Scatter.
-	// (Collectors could be complex and slow, so we call them all at once.)
-	wg.Add(len(r.collectorsByID))
-	go func() {
-		wg.Wait()
-		close(metricChan)
-	}()
+	checkedCollectors := make(chan Collector, len(r.collectorsByID))
+	uncheckedCollectors := make(chan Collector, len(r.uncheckedCollectors))
 	for _, collector := range r.collectorsByID {
-		go func(collector Collector) {
-			defer wg.Done()
-			collector.Collect(metricChan)
-		}(collector)
+		checkedCollectors <- collector
+	}
+	for _, collector := range r.uncheckedCollectors {
+		uncheckedCollectors <- collector
 	}
-
 	// In case pedantic checks are enabled, we have to copy the map before
 	// giving up the RLock.
 	if r.pedanticChecksEnabled {
@@ -392,133 +423,264 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 			registeredDescIDs[id] = struct{}{}
 		}
 	}
-
 	r.mtx.RUnlock()
 
-	// Drain metricChan in case of premature return.
+	wg.Add(goroutineBudget)
+
+	collectWorker := func() {
+		for {
+			select {
+			case collector := <-checkedCollectors:
+				collector.Collect(checkedMetricChan)
+			case collector := <-uncheckedCollectors:
+				collector.Collect(uncheckedMetricChan)
+			default:
+				return
+			}
+			wg.Done()
+		}
+	}
+
+	// Start the first worker now to make sure at least one is running.
+	go collectWorker()
+	goroutineBudget--
+
+	// Close checkedMetricChan and uncheckedMetricChan once all collectors
+	// are collected.
+	go func() {
+		wg.Wait()
+		close(checkedMetricChan)
+		close(uncheckedMetricChan)
+	}()
+
+	// Drain checkedMetricChan and uncheckedMetricChan in case of premature return.
 	defer func() {
-		for range metricChan {
+		if checkedMetricChan != nil {
+			for range checkedMetricChan {
+			}
+		}
+		if uncheckedMetricChan != nil {
+			for range uncheckedMetricChan {
+			}
 		}
 	}()
 
-	// Gather.
-	for metric := range metricChan {
-		// This could be done concurrently, too, but it required locking
-		// of metricFamiliesByName (and of metricHashes if checks are
-		// enabled). Most likely not worth it.
-		desc := metric.Desc()
-		dtoMetric := &dto.Metric{}
-		if err := metric.Write(dtoMetric); err != nil {
-			errs = append(errs, fmt.Errorf(
-				"error collecting metric %v: %s", desc, err,
+	// Copy the channel references so we can nil them out later to remove
+	// them from the select statements below.
+	cmc := checkedMetricChan
+	umc := uncheckedMetricChan
+
+	for {
+		select {
+		case metric, ok := <-cmc:
+			if !ok {
+				cmc = nil
+				break
+			}
+			errs.Append(processMetric(
+				metric, metricFamiliesByName,
+				metricHashes,
+				registeredDescIDs,
 			))
-			continue
+		case metric, ok := <-umc:
+			if !ok {
+				umc = nil
+				break
+			}
+			errs.Append(processMetric(
+				metric, metricFamiliesByName,
+				metricHashes,
+				nil,
+			))
+		default:
+			if goroutineBudget <= 0 || len(checkedCollectors)+len(uncheckedCollectors) == 0 {
+				// All collectors are already being worked on or
+				// we have already as many goroutines started as
+				// there are collectors. Do the same as above,
+				// just without the default.
+				select {
+				case metric, ok := <-cmc:
+					if !ok {
+						cmc = nil
+						break
+					}
+					errs.Append(processMetric(
+						metric, metricFamiliesByName,
+						metricHashes,
+						registeredDescIDs,
+					))
+				case metric, ok := <-umc:
+					if !ok {
+						umc = nil
+						break
+					}
+					errs.Append(processMetric(
+						metric, metricFamiliesByName,
+						metricHashes,
+						nil,
+					))
+				}
+				break
+			}
+			// Start more workers.
+			go collectWorker()
+			goroutineBudget--
+			runtime.Gosched()
 		}
-		metricFamily, ok := metricFamiliesByName[desc.fqName]
-		if ok {
-			if metricFamily.GetHelp() != desc.help {
-				errs = append(errs, fmt.Errorf(
-					"collected metric %s %s has help %q but should have %q",
-					desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
-				))
-				continue
-			}
-			// TODO(beorn7): Simplify switch once Desc has type.
-			switch metricFamily.GetType() {
-			case dto.MetricType_COUNTER:
-				if dtoMetric.Counter == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Counter",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_GAUGE:
-				if dtoMetric.Gauge == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Gauge",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_SUMMARY:
-				if dtoMetric.Summary == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Summary",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_UNTYPED:
-				if dtoMetric.Untyped == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be Untyped",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_HISTOGRAM:
-				if dtoMetric.Histogram == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Histogram",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			default:
-				panic("encountered MetricFamily with invalid type")
-			}
-		} else {
-			metricFamily = &dto.MetricFamily{}
-			metricFamily.Name = proto.String(desc.fqName)
-			metricFamily.Help = proto.String(desc.help)
-			// TODO(beorn7): Simplify switch once Desc has type.
-			switch {
-			case dtoMetric.Gauge != nil:
-				metricFamily.Type = dto.MetricType_GAUGE.Enum()
-			case dtoMetric.Counter != nil:
-				metricFamily.Type = dto.MetricType_COUNTER.Enum()
-			case dtoMetric.Summary != nil:
-				metricFamily.Type = dto.MetricType_SUMMARY.Enum()
-			case dtoMetric.Untyped != nil:
-				metricFamily.Type = dto.MetricType_UNTYPED.Enum()
-			case dtoMetric.Histogram != nil:
-				metricFamily.Type = dto.MetricType_HISTOGRAM.Enum()
-			default:
-				errs = append(errs, fmt.Errorf(
-					"empty metric collected: %s", dtoMetric,
-				))
-				continue
-			}
-			metricFamiliesByName[desc.fqName] = metricFamily
+		// Once both checkedMetricChan and uncheckdMetricChan are closed
+		// and drained, the contraption above will nil out cmc and umc,
+		// and then we can leave the collect loop here.
+		if cmc == nil && umc == nil {
+			break
 		}
-		if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes, dimHashes); err != nil {
-			errs = append(errs, err)
-			continue
-		}
-		if r.pedanticChecksEnabled {
-			// Is the desc registered at all?
-			if _, exist := registeredDescIDs[desc.id]; !exist {
-				errs = append(errs, fmt.Errorf(
-					"collected metric %s %s with unregistered descriptor %s",
-					metricFamily.GetName(), dtoMetric, desc,
-				))
-				continue
-			}
-			if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil {
-				errs = append(errs, err)
-				continue
-			}
-		}
-		metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
 	}
-	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+}
+
+// WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
+// Prometheus text format, and writes it to a temporary file. Upon success, the
+// temporary file is renamed to the provided filename.
+//
+// This is intended for use with the textfile collector of the node exporter.
+// Note that the node exporter expects the filename to be suffixed with ".prom".
+func WriteToTextfile(filename string, g Gatherer) error {
+	tmp, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmp.Name())
+
+	mfs, err := g.Gather()
+	if err != nil {
+		return err
+	}
+	for _, mf := range mfs {
+		if _, err := expfmt.MetricFamilyToText(tmp, mf); err != nil {
+			return err
+		}
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+
+	if err := os.Chmod(tmp.Name(), 0644); err != nil {
+		return err
+	}
+	return os.Rename(tmp.Name(), filename)
+}
+
+// processMetric is an internal helper method only used by the Gather method.
+func processMetric(
+	metric Metric,
+	metricFamiliesByName map[string]*dto.MetricFamily,
+	metricHashes map[uint64]struct{},
+	registeredDescIDs map[uint64]struct{},
+) error {
+	desc := metric.Desc()
+	// Wrapped metrics collected by an unchecked Collector can have an
+	// invalid Desc.
+	if desc.err != nil {
+		return desc.err
+	}
+	dtoMetric := &dto.Metric{}
+	if err := metric.Write(dtoMetric); err != nil {
+		return fmt.Errorf("error collecting metric %v: %s", desc, err)
+	}
+	metricFamily, ok := metricFamiliesByName[desc.fqName]
+	if ok { // Existing name.
+		if metricFamily.GetHelp() != desc.help {
+			return fmt.Errorf(
+				"collected metric %s %s has help %q but should have %q",
+				desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
+			)
+		}
+		// TODO(beorn7): Simplify switch once Desc has type.
+		switch metricFamily.GetType() {
+		case dto.MetricType_COUNTER:
+			if dtoMetric.Counter == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Counter",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_GAUGE:
+			if dtoMetric.Gauge == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Gauge",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_SUMMARY:
+			if dtoMetric.Summary == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Summary",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_UNTYPED:
+			if dtoMetric.Untyped == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be Untyped",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_HISTOGRAM:
+			if dtoMetric.Histogram == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Histogram",
+					desc.fqName, dtoMetric,
+				)
+			}
+		default:
+			panic("encountered MetricFamily with invalid type")
+		}
+	} else { // New name.
+		metricFamily = &dto.MetricFamily{}
+		metricFamily.Name = proto.String(desc.fqName)
+		metricFamily.Help = proto.String(desc.help)
+		// TODO(beorn7): Simplify switch once Desc has type.
+		switch {
+		case dtoMetric.Gauge != nil:
+			metricFamily.Type = dto.MetricType_GAUGE.Enum()
+		case dtoMetric.Counter != nil:
+			metricFamily.Type = dto.MetricType_COUNTER.Enum()
+		case dtoMetric.Summary != nil:
+			metricFamily.Type = dto.MetricType_SUMMARY.Enum()
+		case dtoMetric.Untyped != nil:
+			metricFamily.Type = dto.MetricType_UNTYPED.Enum()
+		case dtoMetric.Histogram != nil:
+			metricFamily.Type = dto.MetricType_HISTOGRAM.Enum()
+		default:
+			return fmt.Errorf("empty metric collected: %s", dtoMetric)
+		}
+		if err := checkSuffixCollisions(metricFamily, metricFamiliesByName); err != nil {
+			return err
+		}
+		metricFamiliesByName[desc.fqName] = metricFamily
+	}
+	if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes); err != nil {
+		return err
+	}
+	if registeredDescIDs != nil {
+		// Is the desc registered at all?
+		if _, exist := registeredDescIDs[desc.id]; !exist {
+			return fmt.Errorf(
+				"collected metric %s %s with unregistered descriptor %s",
+				metricFamily.GetName(), dtoMetric, desc,
+			)
+		}
+		if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil {
+			return err
+		}
+	}
+	metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
+	return nil
 }
 
 // Gatherers is a slice of Gatherer instances that implements the Gatherer
 // interface itself. Its Gather method calls Gather on all Gatherers in the
 // slice in order and returns the merged results. Errors returned from the
-// Gather calles are all returned in a flattened MultiError. Duplicate and
+// Gather calls are all returned in a flattened MultiError. Duplicate and
 // inconsistent Metrics are skipped (first occurrence in slice order wins) and
 // reported in the returned error.
 //
@@ -538,7 +700,6 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 	var (
 		metricFamiliesByName = map[string]*dto.MetricFamily{}
 		metricHashes         = map[uint64]struct{}{}
-		dimHashes            = map[string]uint64{}
 		errs                 MultiError // The collected errors to return in the end.
 	)
 
@@ -575,10 +736,14 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 				existingMF.Name = mf.Name
 				existingMF.Help = mf.Help
 				existingMF.Type = mf.Type
+				if err := checkSuffixCollisions(existingMF, metricFamiliesByName); err != nil {
+					errs = append(errs, err)
+					continue
+				}
 				metricFamiliesByName[mf.GetName()] = existingMF
 			}
 			for _, m := range mf.Metric {
-				if err := checkMetricConsistency(existingMF, m, metricHashes, dimHashes); err != nil {
+				if err := checkMetricConsistency(existingMF, m, metricHashes); err != nil {
 					errs = append(errs, err)
 					continue
 				}
@@ -586,88 +751,80 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 			}
 		}
 	}
-	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
-// metricSorter is a sortable slice of *dto.Metric.
-type metricSorter []*dto.Metric
-
-func (s metricSorter) Len() int {
-	return len(s)
-}
-
-func (s metricSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s metricSorter) Less(i, j int) bool {
-	if len(s[i].Label) != len(s[j].Label) {
-		// This should not happen. The metrics are
-		// inconsistent. However, we have to deal with the fact, as
-		// people might use custom collectors or metric family injection
-		// to create inconsistent metrics. So let's simply compare the
-		// number of labels in this case. That will still yield
-		// reproducible sorting.
-		return len(s[i].Label) < len(s[j].Label)
+// checkSuffixCollisions checks for collisions with the “magic” suffixes the
+// Prometheus text format and the internal metric representation of the
+// Prometheus server add while flattening Summaries and Histograms.
+func checkSuffixCollisions(mf *dto.MetricFamily, mfs map[string]*dto.MetricFamily) error {
+	var (
+		newName              = mf.GetName()
+		newType              = mf.GetType()
+		newNameWithoutSuffix = ""
+	)
+	switch {
+	case strings.HasSuffix(newName, "_count"):
+		newNameWithoutSuffix = newName[:len(newName)-6]
+	case strings.HasSuffix(newName, "_sum"):
+		newNameWithoutSuffix = newName[:len(newName)-4]
+	case strings.HasSuffix(newName, "_bucket"):
+		newNameWithoutSuffix = newName[:len(newName)-7]
 	}
-	for n, lp := range s[i].Label {
-		vi := lp.GetValue()
-		vj := s[j].Label[n].GetValue()
-		if vi != vj {
-			return vi < vj
+	if newNameWithoutSuffix != "" {
+		if existingMF, ok := mfs[newNameWithoutSuffix]; ok {
+			switch existingMF.GetType() {
+			case dto.MetricType_SUMMARY:
+				if !strings.HasSuffix(newName, "_bucket") {
+					return fmt.Errorf(
+						"collected metric named %q collides with previously collected summary named %q",
+						newName, newNameWithoutSuffix,
+					)
+				}
+			case dto.MetricType_HISTOGRAM:
+				return fmt.Errorf(
+					"collected metric named %q collides with previously collected histogram named %q",
+					newName, newNameWithoutSuffix,
+				)
+			}
 		}
 	}
-
-	// We should never arrive here. Multiple metrics with the same
-	// label set in the same scrape will lead to undefined ingestion
-	// behavior. However, as above, we have to provide stable sorting
-	// here, even for inconsistent metrics. So sort equal metrics
-	// by their timestamp, with missing timestamps (implying "now")
-	// coming last.
-	if s[i].TimestampMs == nil {
-		return false
-	}
-	if s[j].TimestampMs == nil {
-		return true
-	}
-	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
-}
-
-// normalizeMetricFamilies returns a MetricFamily slice with empty
-// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
-// the slice, with the contained Metrics sorted within each MetricFamily.
-func normalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
-	for _, mf := range metricFamiliesByName {
-		sort.Sort(metricSorter(mf.Metric))
-	}
-	names := make([]string, 0, len(metricFamiliesByName))
-	for name, mf := range metricFamiliesByName {
-		if len(mf.Metric) > 0 {
-			names = append(names, name)
+	if newType == dto.MetricType_SUMMARY || newType == dto.MetricType_HISTOGRAM {
+		if _, ok := mfs[newName+"_count"]; ok {
+			return fmt.Errorf(
+				"collected histogram or summary named %q collides with previously collected metric named %q",
+				newName, newName+"_count",
+			)
+		}
+		if _, ok := mfs[newName+"_sum"]; ok {
+			return fmt.Errorf(
+				"collected histogram or summary named %q collides with previously collected metric named %q",
+				newName, newName+"_sum",
+			)
 		}
 	}
-	sort.Strings(names)
-	result := make([]*dto.MetricFamily, 0, len(names))
-	for _, name := range names {
-		result = append(result, metricFamiliesByName[name])
+	if newType == dto.MetricType_HISTOGRAM {
+		if _, ok := mfs[newName+"_bucket"]; ok {
+			return fmt.Errorf(
+				"collected histogram named %q collides with previously collected metric named %q",
+				newName, newName+"_bucket",
+			)
+		}
 	}
-	return result
+	return nil
 }
 
 // checkMetricConsistency checks if the provided Metric is consistent with the
-// provided MetricFamily. It also hashed the Metric labels and the MetricFamily
-// name. If the resulting hash is alread in the provided metricHashes, an error
-// is returned. If not, it is added to metricHashes. The provided dimHashes maps
-// MetricFamily names to their dimHash (hashed sorted label names). If dimHashes
-// doesn't yet contain a hash for the provided MetricFamily, it is
-// added. Otherwise, an error is returned if the existing dimHashes in not equal
-// the calculated dimHash.
+// provided MetricFamily. It also hashes the Metric labels and the MetricFamily
+// name. If the resulting hash is already in the provided metricHashes, an error
+// is returned. If not, it is added to metricHashes.
 func checkMetricConsistency(
 	metricFamily *dto.MetricFamily,
 	dtoMetric *dto.Metric,
 	metricHashes map[uint64]struct{},
-	dimHashes map[string]uint64,
 ) error {
+	name := metricFamily.GetName()
+
 	// Type consistency with metric family.
 	if metricFamily.GetType() == dto.MetricType_GAUGE && dtoMetric.Gauge == nil ||
 		metricFamily.GetType() == dto.MetricType_COUNTER && dtoMetric.Counter == nil ||
@@ -675,47 +832,65 @@ func checkMetricConsistency(
 		metricFamily.GetType() == dto.MetricType_HISTOGRAM && dtoMetric.Histogram == nil ||
 		metricFamily.GetType() == dto.MetricType_UNTYPED && dtoMetric.Untyped == nil {
 		return fmt.Errorf(
-			"collected metric %s %s is not a %s",
-			metricFamily.GetName(), dtoMetric, metricFamily.GetType(),
+			"collected metric %q { %s} is not a %s",
+			name, dtoMetric, metricFamily.GetType(),
 		)
 	}
 
+	previousLabelName := ""
 	for _, labelPair := range dtoMetric.GetLabel() {
-		if !utf8.ValidString(*labelPair.Value) {
-			return fmt.Errorf("collected metric's label %s is not utf8: %#v", *labelPair.Name, *labelPair.Value)
+		labelName := labelPair.GetName()
+		if labelName == previousLabelName {
+			return fmt.Errorf(
+				"collected metric %q { %s} has two or more labels with the same name: %s",
+				name, dtoMetric, labelName,
+			)
 		}
+		if !checkLabelName(labelName) {
+			return fmt.Errorf(
+				"collected metric %q { %s} has a label with an invalid name: %s",
+				name, dtoMetric, labelName,
+			)
+		}
+		if dtoMetric.Summary != nil && labelName == quantileLabel {
+			return fmt.Errorf(
+				"collected metric %q { %s} must not have an explicit %q label",
+				name, dtoMetric, quantileLabel,
+			)
+		}
+		if !utf8.ValidString(labelPair.GetValue()) {
+			return fmt.Errorf(
+				"collected metric %q { %s} has a label named %q whose value is not utf8: %#v",
+				name, dtoMetric, labelName, labelPair.GetValue())
+		}
+		previousLabelName = labelName
 	}
 
-	// Is the metric unique (i.e. no other metric with the same name and the same label values)?
+	// Is the metric unique (i.e. no other metric with the same name and the same labels)?
 	h := hashNew()
-	h = hashAdd(h, metricFamily.GetName())
+	h = hashAdd(h, name)
 	h = hashAddByte(h, separatorByte)
-	dh := hashNew()
 	// Make sure label pairs are sorted. We depend on it for the consistency
 	// check.
-	sort.Sort(LabelPairSorter(dtoMetric.Label))
+	if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
+		// We cannot sort dtoMetric.Label in place as it is immutable by contract.
+		copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
+		copy(copiedLabels, dtoMetric.Label)
+		sort.Sort(labelPairSorter(copiedLabels))
+		dtoMetric.Label = copiedLabels
+	}
 	for _, lp := range dtoMetric.Label {
+		h = hashAdd(h, lp.GetName())
+		h = hashAddByte(h, separatorByte)
 		h = hashAdd(h, lp.GetValue())
 		h = hashAddByte(h, separatorByte)
-		dh = hashAdd(dh, lp.GetName())
-		dh = hashAddByte(dh, separatorByte)
 	}
 	if _, exists := metricHashes[h]; exists {
 		return fmt.Errorf(
-			"collected metric %s %s was collected before with the same name and label values",
-			metricFamily.GetName(), dtoMetric,
+			"collected metric %q { %s} was collected before with the same name and label values",
+			name, dtoMetric,
 		)
 	}
-	if dimHash, ok := dimHashes[metricFamily.GetName()]; ok {
-		if dimHash != dh {
-			return fmt.Errorf(
-				"collected metric %s %s has label dimensions inconsistent with previously collected metrics in the same metric family",
-				metricFamily.GetName(), dtoMetric,
-			)
-		}
-	} else {
-		dimHashes[metricFamily.GetName()] = dh
-	}
 	metricHashes[h] = struct{}{}
 	return nil
 }
@@ -734,8 +909,8 @@ func checkDescConsistency(
 	}
 
 	// Is the desc consistent with the content of the metric?
-	lpsFromDesc := make([]*dto.LabelPair, 0, len(dtoMetric.Label))
-	lpsFromDesc = append(lpsFromDesc, desc.constLabelPairs...)
+	lpsFromDesc := make([]*dto.LabelPair, len(desc.constLabelPairs), len(dtoMetric.Label))
+	copy(lpsFromDesc, desc.constLabelPairs)
 	for _, l := range desc.variableLabels {
 		lpsFromDesc = append(lpsFromDesc, &dto.LabelPair{
 			Name: proto.String(l),
@@ -747,7 +922,7 @@ func checkDescConsistency(
 			metricFamily.GetName(), dtoMetric, desc,
 		)
 	}
-	sort.Sort(LabelPairSorter(lpsFromDesc))
+	sort.Sort(labelPairSorter(lpsFromDesc))
 	for i, lpFromDesc := range lpsFromDesc {
 		lpFromMetric := dtoMetric.Label[i]
 		if lpFromDesc.GetName() != lpFromMetric.GetName() ||

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -16,8 +16,10 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/beorn7/perks/quantile"
@@ -36,7 +38,10 @@ const quantileLabel = "quantile"
 //
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
-// as rank estimations.
+// as rank estimations. However, the default behavior will change in the
+// upcoming v1.0.0 of the library. There will be no rank estimations at all by
+// default. For a sane transition, it is recommended to set the desired rank
+// estimations explicitly.
 //
 // Note that the rank estimations cannot be aggregated in a meaningful way with
 // the Prometheus query language (i.e. you cannot average or add them). If you
@@ -56,7 +61,7 @@ type Summary interface {
 // DefObjectives are the default Summary quantile values.
 //
 // Deprecated: DefObjectives will not be used as the default objectives in
-// v0.10 of the library. The default Summary will have no quantiles then.
+// v1.0.0 of the library. The default Summary will have no quantiles then.
 var (
 	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
 
@@ -78,8 +83,10 @@ const (
 )
 
 // SummaryOpts bundles the options for creating a Summary metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. While all other fields are
+// optional and can safely be left at their zero value, it is recommended to set
+// a help string and to explicitly set the Objectives field to the desired value
+// as the default value will change in the upcoming v1.0.0 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -90,29 +97,27 @@ type SummaryOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Summary. Mandatory!
+	// Help provides information about this Summary.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Summary. Summaries with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// SummaryVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Summaries with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
+	// Due to the way a Summary is represented in the Prometheus text format
+	// and how it is handled by the Prometheus server internally, “quantile”
+	// is an illegal label name. Construction of a Summary or SummaryVec
+	// will panic if this label name is used in ConstLabels.
 	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Objectives defines the quantile rank estimates with their respective
@@ -122,9 +127,10 @@ type SummaryOpts struct {
 	// its zero value (i.e. nil). To create a Summary without Objectives,
 	// set it to an empty map (i.e. map[float64]float64{}).
 	//
-	// Deprecated: Note that the current value of DefObjectives is
-	// deprecated. It will be replaced by an empty map in v0.10 of the
-	// library. Please explicitly set Objectives to the desired value.
+	// Note that the current value of DefObjectives is deprecated. It will
+	// be replaced by an empty map in v1.0.0 of the library. Please
+	// explicitly set Objectives to the desired value to avoid problems
+	// during the transition.
 	Objectives map[float64]float64
 
 	// MaxAge defines the duration for which an observation stays relevant
@@ -148,7 +154,7 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
-// Great fuck-up with the sliding-window decay algorithm... The Merge method of
+// Problem with the sliding-window decay algorithm... The Merge method of
 // perk/quantile is actually not working as advertised - and it might be
 // unfixable, as the underlying algorithm is apparently not capable of merging
 // summaries in the first place. To avoid using Merge, we are currently adding
@@ -178,7 +184,7 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -211,6 +217,17 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		opts.BufCap = DefBufCap
 	}
 
+	if len(opts.Objectives) == 0 {
+		// Use the lock-free implementation of a Summary without objectives.
+		s := &noObjectivesSummary{
+			desc:       desc,
+			labelPairs: makeLabelPairs(desc, labelValues),
+			counts:     [2]*summaryCounts{&summaryCounts{}, &summaryCounts{}},
+		}
+		s.init(s) // Init self-collection.
+		return s
+	}
+
 	s := &summary{
 		desc: desc,
 
@@ -379,6 +396,116 @@ func (s *summary) swapBufs(now time.Time) {
 	}
 }
 
+type summaryCounts struct {
+	// sumBits contains the bits of the float64 representing the sum of all
+	// observations. sumBits and count have to go first in the struct to
+	// guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	sumBits uint64
+	count   uint64
+}
+
+type noObjectivesSummary struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// summaryCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the summary) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
+
+	selfCollector
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
+
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*summaryCounts
+
+	labelPairs []*dto.LabelPair
+}
+
+func (s *noObjectivesSummary) Desc() *Desc {
+	return s.desc
+}
+
+func (s *noObjectivesSummary) Observe(v float64) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1)
+	hotCounts := s.counts[n>>63]
+
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			break
+		}
+	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
+}
+
+func (s *noObjectivesSummary) Write(out *dto.Metric) error {
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	s.writeMtx.Lock()
+	defer s.writeMtx.Unlock()
+
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := s.counts[n>>63]
+	coldCounts := s.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	sum := &dto.Summary{
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+
+	out.Summary = sum
+	out.Label = s.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + sum.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	return nil
+}
+
 type quantSort []*dto.Quantile
 
 func (s quantSort) Len() int {
@@ -404,7 +531,16 @@ type SummaryVec struct {
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
 // partitioned by the given label names.
+//
+// Due to the way a Summary is represented in the Prometheus text format and how
+// it is handled by the Prometheus server internally, “quantile” is an illegal
+// label name. NewSummaryVec will panic if this label name is used.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
+	for _, ln := range labelNames {
+		if ln == quantileLabel {
+			panic(errQuantileLabelNotAllowed)
+		}
+	}
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
@@ -428,13 +564,13 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 //
 // Keeping the Summary for later use is possible (and should be considered if
 // performance is critical), but keep in mind that Reset, DeleteLabelValues and
-// Delete can be used to delete the Summary from the SummaryVec. In that case, the
-// Summary will still exist, but it will not be exported anymore, even if a
+// Delete can be used to delete the Summary from the SummaryVec. In that case,
+// the Summary will still exist, but it will not be exported anymore, even if a
 // Summary with the same label values is created later. See also the CounterVec
 // example.
 //
 // An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
+// number of VariableLabels in Desc (minus any curried labels).
 //
 // Note that for more than one label value, this method is prone to mistakes
 // caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
@@ -442,8 +578,8 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 // latter has a much more readable (albeit more verbose) syntax, but it comes
 // with a performance overhead (for creating and processing the Labels map).
 // See also the GaugeVec example.
-func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
-	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
+func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Observer), err
 	}
@@ -457,13 +593,13 @@ func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
 // the same as for GetMetricWithLabelValues.
 //
 // An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
+// with those of the VariableLabels in Desc (minus any curried labels).
 //
 // This method is used for the same purpose as
 // GetMetricWithLabelValues(...string). See there for pros and cons of the two
 // methods.
-func (m *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
-	metric, err := m.metricVec.getMetricWith(labels)
+func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Observer), err
 	}
@@ -471,18 +607,57 @@ func (m *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *SummaryVec) WithLabelValues(lvs ...string) Observer {
-	return m.metricVec.withLabelValues(lvs...).(Observer)
+func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
+	s, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return s
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *SummaryVec) With(labels Labels) Observer {
-	return m.metricVec.with(labels).(Observer)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *SummaryVec) With(labels Labels) Observer {
+	s, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return s
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the SummaryVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &SummaryVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constSummary struct {
@@ -535,7 +710,7 @@ func (s *constSummary) Write(out *dto.Metric) error {
 //     map[float64]float64{0.5: 0.23, 0.99: 0.56}
 //
 // NewConstSummary returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstSummary(
 	desc *Desc,
 	count uint64,
@@ -543,6 +718,9 @@ func NewConstSummary(
 	quantiles map[float64]float64,
 	labelValues ...string,
 ) (Metric, error) {
+	if desc.err != nil {
+		return nil, desc.err
+	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/client_golang/prometheus/timer.go

@@ -39,13 +39,16 @@ func NewTimer(o Observer) *Timer {
 
 // ObserveDuration records the duration passed since the Timer was created with
 // NewTimer. It calls the Observe method of the Observer provided during
-// construction with the duration in seconds as an argument. ObserveDuration is
-// usually called with a defer statement.
+// construction with the duration in seconds as an argument. The observed
+// duration is also returned. ObserveDuration is usually called with a defer
+// statement.
 //
 // Note that this method is only guaranteed to never observe negative durations
 // if used with Go1.9+.
-func (t *Timer) ObserveDuration() {
+func (t *Timer) ObserveDuration() time.Duration {
+	d := time.Since(t.begin)
 	if t.observer != nil {
-		t.observer.Observe(time.Since(t.begin).Seconds())
+		t.observer.Observe(d.Seconds())
 	}
+	return d
 }

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -15,14 +15,11 @@ package prometheus
 
 import (
 	"fmt"
-	"math"
 	"sort"
-	"sync/atomic"
-	"time"
-
-	dto "github.com/prometheus/client_model/go"
 
 	"github.com/golang/protobuf/proto"
+
+	dto "github.com/prometheus/client_model/go"
 )
 
 // ValueType is an enumeration of metric types that represent a simple value.
@@ -36,79 +33,6 @@ const (
 	UntypedValue
 )
 
-// value is a generic metric for simple values. It implements Metric, Collector,
-// Counter, Gauge, and Untyped. Its effective type is determined by
-// ValueType. This is a low-level building block used by the library to back the
-// implementations of Counter, Gauge, and Untyped.
-type value struct {
-	// valBits contains the bits of the represented float64 value. It has
-	// to go first in the struct to guarantee alignment for atomic
-	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	valBits uint64
-
-	selfCollector
-
-	desc       *Desc
-	valType    ValueType
-	labelPairs []*dto.LabelPair
-}
-
-// newValue returns a newly allocated value with the given Desc, ValueType,
-// sample value and label values. It panics if the number of label
-// values is different from the number of variable labels in Desc.
-func newValue(desc *Desc, valueType ValueType, val float64, labelValues ...string) *value {
-	if len(labelValues) != len(desc.variableLabels) {
-		panic(errInconsistentCardinality)
-	}
-	result := &value{
-		desc:       desc,
-		valType:    valueType,
-		valBits:    math.Float64bits(val),
-		labelPairs: makeLabelPairs(desc, labelValues),
-	}
-	result.init(result)
-	return result
-}
-
-func (v *value) Desc() *Desc {
-	return v.desc
-}
-
-func (v *value) Set(val float64) {
-	atomic.StoreUint64(&v.valBits, math.Float64bits(val))
-}
-
-func (v *value) SetToCurrentTime() {
-	v.Set(float64(time.Now().UnixNano()) / 1e9)
-}
-
-func (v *value) Inc() {
-	v.Add(1)
-}
-
-func (v *value) Dec() {
-	v.Add(-1)
-}
-
-func (v *value) Add(val float64) {
-	for {
-		oldBits := atomic.LoadUint64(&v.valBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
-		if atomic.CompareAndSwapUint64(&v.valBits, oldBits, newBits) {
-			return
-		}
-	}
-}
-
-func (v *value) Sub(val float64) {
-	v.Add(val * -1)
-}
-
-func (v *value) Write(out *dto.Metric) error {
-	val := math.Float64frombits(atomic.LoadUint64(&v.valBits))
-	return populateMetric(v.valType, val, v.labelPairs, out)
-}
-
 // valueFunc is a generic metric for simple values retrieved on collect time
 // from a function. It implements Metric and Collector. Its effective type is
 // determined by ValueType. This is a low-level building block used by the
@@ -153,8 +77,12 @@ func (v *valueFunc) Write(out *dto.Metric) error {
 // operations. However, when implementing custom Collectors, it is useful as a
 // throw-away metric that is generated on the fly to send it to Prometheus in
 // the Collect method. NewConstMetric returns an error if the length of
-// labelValues is not consistent with the variable labels in Desc.
+// labelValues is not consistent with the variable labels in Desc or if Desc is
+// invalid.
 func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) {
+	if desc.err != nil {
+		return nil, desc.err
+	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}
@@ -228,9 +156,7 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 			Value: proto.String(labelValues[i]),
 		})
 	}
-	for _, lp := range desc.constLabelPairs {
-		labelPairs = append(labelPairs, lp)
-	}
-	sort.Sort(LabelPairSorter(labelPairs))
+	labelPairs = append(labelPairs, desc.constLabelPairs...)
+	sort.Sort(labelPairSorter(labelPairs))
 	return labelPairs
 }

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -23,88 +23,31 @@ import (
 // metricVec is a Collector to bundle metrics of the same name that differ in
 // their label values. metricVec is not used directly (and therefore
 // unexported). It is used as a building block for implementations of vectors of
-// a given metric type, like GaugeVec, CounterVec, SummaryVec, HistogramVec, and
-// UntypedVec.
+// a given metric type, like GaugeVec, CounterVec, SummaryVec, and HistogramVec.
+// It also handles label currying. It uses basicMetricVec internally.
 type metricVec struct {
-	mtx      sync.RWMutex // Protects the children.
-	children map[uint64][]metricWithLabelValues
-	desc     *Desc
+	*metricMap
 
-	newMetric   func(labelValues ...string) Metric
-	hashAdd     func(h uint64, s string) uint64 // replace hash function for testing collision handling
+	curry []curriedLabelValue
+
+	// hashAdd and hashAddByte can be replaced for testing collision handling.
+	hashAdd     func(h uint64, s string) uint64
 	hashAddByte func(h uint64, b byte) uint64
 }
 
 // newMetricVec returns an initialized metricVec.
 func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *metricVec {
 	return &metricVec{
-		children:    map[uint64][]metricWithLabelValues{},
-		desc:        desc,
-		newMetric:   newMetric,
+		metricMap: &metricMap{
+			metrics:   map[uint64][]metricWithLabelValues{},
+			desc:      desc,
+			newMetric: newMetric,
+		},
 		hashAdd:     hashAdd,
 		hashAddByte: hashAddByte,
 	}
 }
 
-// metricWithLabelValues provides the metric and its label values for
-// disambiguation on hash collision.
-type metricWithLabelValues struct {
-	values []string
-	metric Metric
-}
-
-// Describe implements Collector. The length of the returned slice
-// is always one.
-func (m *metricVec) Describe(ch chan<- *Desc) {
-	ch <- m.desc
-}
-
-// Collect implements Collector.
-func (m *metricVec) Collect(ch chan<- Metric) {
-	m.mtx.RLock()
-	defer m.mtx.RUnlock()
-
-	for _, metrics := range m.children {
-		for _, metric := range metrics {
-			ch <- metric.metric
-		}
-	}
-}
-
-func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) {
-	h, err := m.hashLabelValues(lvs)
-	if err != nil {
-		return nil, err
-	}
-
-	return m.getOrCreateMetricWithLabelValues(h, lvs), nil
-}
-
-func (m *metricVec) getMetricWith(labels Labels) (Metric, error) {
-	h, err := m.hashLabels(labels)
-	if err != nil {
-		return nil, err
-	}
-
-	return m.getOrCreateMetricWithLabels(h, labels), nil
-}
-
-func (m *metricVec) withLabelValues(lvs ...string) Metric {
-	metric, err := m.getMetricWithLabelValues(lvs...)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
-func (m *metricVec) with(labels Labels) Metric {
-	metric, err := m.getMetricWith(labels)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
 // DeleteLabelValues removes the metric where the variable labels are the same
 // as those passed in as labels (same order as the VariableLabels in Desc). It
 // returns true if a metric was deleted.
@@ -121,14 +64,12 @@ func (m *metricVec) with(labels Labels) Metric {
 // with a performance overhead (for creating and processing the Labels map).
 // See also the CounterVec example.
 func (m *metricVec) DeleteLabelValues(lvs ...string) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
 	h, err := m.hashLabelValues(lvs)
 	if err != nil {
 		return false
 	}
-	return m.deleteByHashWithLabelValues(h, lvs)
+
+	return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry)
 }
 
 // Delete deletes the metric where the variable labels are the same as those
@@ -142,35 +83,190 @@ func (m *metricVec) DeleteLabelValues(lvs ...string) bool {
 // This method is used for the same purpose as DeleteLabelValues(...string). See
 // there for pros and cons of the two methods.
 func (m *metricVec) Delete(labels Labels) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
 	h, err := m.hashLabels(labels)
 	if err != nil {
 		return false
 	}
 
-	return m.deleteByHashWithLabels(h, labels)
+	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
+}
+
+func (m *metricVec) curryWith(labels Labels) (*metricVec, error) {
+	var (
+		newCurry []curriedLabelValue
+		oldCurry = m.curry
+		iCurry   int
+	)
+	for i, label := range m.desc.variableLabels {
+		val, ok := labels[label]
+		if iCurry < len(oldCurry) && oldCurry[iCurry].index == i {
+			if ok {
+				return nil, fmt.Errorf("label name %q is already curried", label)
+			}
+			newCurry = append(newCurry, oldCurry[iCurry])
+			iCurry++
+		} else {
+			if !ok {
+				continue // Label stays uncurried.
+			}
+			newCurry = append(newCurry, curriedLabelValue{i, val})
+		}
+	}
+	if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 {
+		return nil, fmt.Errorf("%d unknown label(s) found during currying", l)
+	}
+
+	return &metricVec{
+		metricMap:   m.metricMap,
+		curry:       newCurry,
+		hashAdd:     m.hashAdd,
+		hashAddByte: m.hashAddByte,
+	}, nil
+}
+
+func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) {
+	h, err := m.hashLabelValues(lvs)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil
+}
+
+func (m *metricVec) getMetricWith(labels Labels) (Metric, error) {
+	h, err := m.hashLabels(labels)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil
+}
+
+func (m *metricVec) hashLabelValues(vals []string) (uint64, error) {
+	if err := validateLabelValues(vals, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
+	}
+
+	var (
+		h             = hashNew()
+		curry         = m.curry
+		iVals, iCurry int
+	)
+	for i := 0; i < len(m.desc.variableLabels); i++ {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			h = m.hashAdd(h, vals[iVals])
+			iVals++
+		}
+		h = m.hashAddByte(h, model.SeparatorByte)
+	}
+	return h, nil
+}
+
+func (m *metricVec) hashLabels(labels Labels) (uint64, error) {
+	if err := validateValuesInLabels(labels, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
+	}
+
+	var (
+		h      = hashNew()
+		curry  = m.curry
+		iCurry int
+	)
+	for i, label := range m.desc.variableLabels {
+		val, ok := labels[label]
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if ok {
+				return 0, fmt.Errorf("label name %q is already curried", label)
+			}
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			if !ok {
+				return 0, fmt.Errorf("label name %q missing in label map", label)
+			}
+			h = m.hashAdd(h, val)
+		}
+		h = m.hashAddByte(h, model.SeparatorByte)
+	}
+	return h, nil
+}
+
+// metricWithLabelValues provides the metric and its label values for
+// disambiguation on hash collision.
+type metricWithLabelValues struct {
+	values []string
+	metric Metric
+}
+
+// curriedLabelValue sets the curried value for a label at the given index.
+type curriedLabelValue struct {
+	index int
+	value string
+}
+
+// metricMap is a helper for metricVec and shared between differently curried
+// metricVecs.
+type metricMap struct {
+	mtx       sync.RWMutex // Protects metrics.
+	metrics   map[uint64][]metricWithLabelValues
+	desc      *Desc
+	newMetric func(labelValues ...string) Metric
+}
+
+// Describe implements Collector. It will send exactly one Desc to the provided
+// channel.
+func (m *metricMap) Describe(ch chan<- *Desc) {
+	ch <- m.desc
+}
+
+// Collect implements Collector.
+func (m *metricMap) Collect(ch chan<- Metric) {
+	m.mtx.RLock()
+	defer m.mtx.RUnlock()
+
+	for _, metrics := range m.metrics {
+		for _, metric := range metrics {
+			ch <- metric.metric
+		}
+	}
+}
+
+// Reset deletes all metrics in this vector.
+func (m *metricMap) Reset() {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	for h := range m.metrics {
+		delete(m.metrics, h)
+	}
 }
 
 // deleteByHashWithLabelValues removes the metric from the hash bucket h. If
 // there are multiple matches in the bucket, use lvs to select a metric and
 // remove only that metric.
-func (m *metricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
-	metrics, ok := m.children[h]
+func (m *metricMap) deleteByHashWithLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
 	if !ok {
 		return false
 	}
 
-	i := m.findMetricWithLabelValues(metrics, lvs)
+	i := findMetricWithLabelValues(metrics, lvs, curry)
 	if i >= len(metrics) {
 		return false
 	}
 
 	if len(metrics) > 1 {
-		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
 	} else {
-		delete(m.children, h)
+		delete(m.metrics, h)
 	}
 	return true
 }
@@ -178,71 +274,38 @@ func (m *metricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
 // deleteByHashWithLabels removes the metric from the hash bucket h. If there
 // are multiple matches in the bucket, use lvs to select a metric and remove
 // only that metric.
-func (m *metricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
-	metrics, ok := m.children[h]
+func (m *metricMap) deleteByHashWithLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
 	if !ok {
 		return false
 	}
-	i := m.findMetricWithLabels(metrics, labels)
+	i := findMetricWithLabels(m.desc, metrics, labels, curry)
 	if i >= len(metrics) {
 		return false
 	}
 
 	if len(metrics) > 1 {
-		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
 	} else {
-		delete(m.children, h)
+		delete(m.metrics, h)
 	}
 	return true
 }
 
-// Reset deletes all metrics in this vector.
-func (m *metricVec) Reset() {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
-	for h := range m.children {
-		delete(m.children, h)
-	}
-}
-
-func (m *metricVec) hashLabelValues(vals []string) (uint64, error) {
-	if err := validateLabelValues(vals, len(m.desc.variableLabels)); err != nil {
-		return 0, err
-	}
-
-	h := hashNew()
-	for _, val := range vals {
-		h = m.hashAdd(h, val)
-		h = m.hashAddByte(h, model.SeparatorByte)
-	}
-	return h, nil
-}
-
-func (m *metricVec) hashLabels(labels Labels) (uint64, error) {
-	if err := validateValuesInLabels(labels, len(m.desc.variableLabels)); err != nil {
-		return 0, err
-	}
-
-	h := hashNew()
-	for _, label := range m.desc.variableLabels {
-		val, ok := labels[label]
-		if !ok {
-			return 0, fmt.Errorf("label name %q missing in label map", label)
-		}
-		h = m.hashAdd(h, val)
-		h = m.hashAddByte(h, model.SeparatorByte)
-	}
-	return h, nil
-}
-
 // getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric {
+func (m *metricMap) getOrCreateMetricWithLabelValues(
+	hash uint64, lvs []string, curry []curriedLabelValue,
+) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs)
+	metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs, curry)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -250,13 +313,11 @@ func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs)
+	metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs, curry)
 	if !ok {
-		// Copy to avoid allocation in case wo don't go down this code path.
-		copiedLVs := make([]string, len(lvs))
-		copy(copiedLVs, lvs)
-		metric = m.newMetric(copiedLVs...)
-		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: copiedLVs, metric: metric})
+		inlinedLVs := inlineLabelValues(lvs, curry)
+		metric = m.newMetric(inlinedLVs...)
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: inlinedLVs, metric: metric})
 	}
 	return metric
 }
@@ -265,9 +326,11 @@ func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *metricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric {
+func (m *metricMap) getOrCreateMetricWithLabels(
+	hash uint64, labels Labels, curry []curriedLabelValue,
+) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithHashAndLabels(hash, labels)
+	metric, ok := m.getMetricWithHashAndLabels(hash, labels, curry)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -275,21 +338,23 @@ func (m *metricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metr
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithHashAndLabels(hash, labels)
+	metric, ok = m.getMetricWithHashAndLabels(hash, labels, curry)
 	if !ok {
-		lvs := m.extractLabelValues(labels)
+		lvs := extractLabelValues(m.desc, labels, curry)
 		metric = m.newMetric(lvs...)
-		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric})
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: lvs, metric: metric})
 	}
 	return metric
 }
 
 // getMetricWithHashAndLabelValues gets a metric while handling possible
 // collisions in the hash space. Must be called while holding the read mutex.
-func (m *metricVec) getMetricWithHashAndLabelValues(h uint64, lvs []string) (Metric, bool) {
-	metrics, ok := m.children[h]
+func (m *metricMap) getMetricWithHashAndLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
 	if ok {
-		if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) {
+		if i := findMetricWithLabelValues(metrics, lvs, curry); i < len(metrics) {
 			return metrics[i].metric, true
 		}
 	}
@@ -298,10 +363,12 @@ func (m *metricVec) getMetricWithHashAndLabelValues(h uint64, lvs []string) (Met
 
 // getMetricWithHashAndLabels gets a metric while handling possible collisions in
 // the hash space. Must be called while holding read mutex.
-func (m *metricVec) getMetricWithHashAndLabels(h uint64, labels Labels) (Metric, bool) {
-	metrics, ok := m.children[h]
+func (m *metricMap) getMetricWithHashAndLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
 	if ok {
-		if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) {
+		if i := findMetricWithLabels(m.desc, metrics, labels, curry); i < len(metrics) {
 			return metrics[i].metric, true
 		}
 	}
@@ -310,9 +377,11 @@ func (m *metricVec) getMetricWithHashAndLabels(h uint64, labels Labels) (Metric,
 
 // findMetricWithLabelValues returns the index of the matching metric or
 // len(metrics) if not found.
-func (m *metricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int {
+func findMetricWithLabelValues(
+	metrics []metricWithLabelValues, lvs []string, curry []curriedLabelValue,
+) int {
 	for i, metric := range metrics {
-		if m.matchLabelValues(metric.values, lvs) {
+		if matchLabelValues(metric.values, lvs, curry) {
 			return i
 		}
 	}
@@ -321,32 +390,51 @@ func (m *metricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, l
 
 // findMetricWithLabels returns the index of the matching metric or len(metrics)
 // if not found.
-func (m *metricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int {
+func findMetricWithLabels(
+	desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue,
+) int {
 	for i, metric := range metrics {
-		if m.matchLabels(metric.values, labels) {
+		if matchLabels(desc, metric.values, labels, curry) {
 			return i
 		}
 	}
 	return len(metrics)
 }
 
-func (m *metricVec) matchLabelValues(values []string, lvs []string) bool {
-	if len(values) != len(lvs) {
+func matchLabelValues(values []string, lvs []string, curry []curriedLabelValue) bool {
+	if len(values) != len(lvs)+len(curry) {
 		return false
 	}
+	var iLVs, iCurry int
 	for i, v := range values {
-		if v != lvs[i] {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if v != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
+		if v != lvs[iLVs] {
 			return false
 		}
+		iLVs++
 	}
 	return true
 }
 
-func (m *metricVec) matchLabels(values []string, labels Labels) bool {
-	if len(labels) != len(values) {
+func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
+	if len(values) != len(labels)+len(curry) {
 		return false
 	}
-	for i, k := range m.desc.variableLabels {
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if values[i] != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
 		if values[i] != labels[k] {
 			return false
 		}
@@ -354,10 +442,31 @@ func (m *metricVec) matchLabels(values []string, labels Labels) bool {
 	return true
 }
 
-func (m *metricVec) extractLabelValues(labels Labels) []string {
-	labelValues := make([]string, len(labels))
-	for i, k := range m.desc.variableLabels {
+func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(labels)+len(curry))
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
 		labelValues[i] = labels[k]
 	}
 	return labelValues
 }
+
+func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(lvs)+len(curry))
+	var iCurry, iLVs int
+	for i := range labelValues {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
+		labelValues[i] = lvs[iLVs]
+		iLVs++
+	}
+	return labelValues
+}

vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -0,0 +1,179 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/golang/protobuf/proto"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// WrapRegistererWith returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided Labels to all Metrics it collects (as
+// ConstLabels). The Metrics collected by the unmodified Collector must not
+// duplicate any of those labels.
+//
+// WrapRegistererWith provides a way to add fixed labels to a subset of
+// Collectors. It should not be used to add fixed labels to all metrics exposed.
+//
+// The Collector example demonstrates a use of WrapRegistererWith.
+func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		labels:            labels,
+	}
+}
+
+// WrapRegistererWithPrefix returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided prefix to the name of all Metrics it collects.
+//
+// WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
+// a sub-system. To make this work, register metrics of the sub-system with the
+// wrapping Registerer returned by WrapRegistererWithPrefix. It is rarely useful
+// to use the same prefix for all metrics exposed. In particular, do not prefix
+// metric names that are standardized across applications, as that would break
+// horizontal monitoring, for example the metrics provided by the Go collector
+// (see NewGoCollector) and the process collector (see NewProcessCollector). (In
+// fact, those metrics are already prefixed with “go_” or “process_”,
+// respectively.)
+func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		prefix:            prefix,
+	}
+}
+
+type wrappingRegisterer struct {
+	wrappedRegisterer Registerer
+	prefix            string
+	labels            Labels
+}
+
+func (r *wrappingRegisterer) Register(c Collector) error {
+	return r.wrappedRegisterer.Register(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
+	for _, c := range cs {
+		if err := r.Register(c); err != nil {
+			panic(err)
+		}
+	}
+}
+
+func (r *wrappingRegisterer) Unregister(c Collector) bool {
+	return r.wrappedRegisterer.Unregister(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+type wrappingCollector struct {
+	wrappedCollector Collector
+	prefix           string
+	labels           Labels
+}
+
+func (c *wrappingCollector) Collect(ch chan<- Metric) {
+	wrappedCh := make(chan Metric)
+	go func() {
+		c.wrappedCollector.Collect(wrappedCh)
+		close(wrappedCh)
+	}()
+	for m := range wrappedCh {
+		ch <- &wrappingMetric{
+			wrappedMetric: m,
+			prefix:        c.prefix,
+			labels:        c.labels,
+		}
+	}
+}
+
+func (c *wrappingCollector) Describe(ch chan<- *Desc) {
+	wrappedCh := make(chan *Desc)
+	go func() {
+		c.wrappedCollector.Describe(wrappedCh)
+		close(wrappedCh)
+	}()
+	for desc := range wrappedCh {
+		ch <- wrapDesc(desc, c.prefix, c.labels)
+	}
+}
+
+type wrappingMetric struct {
+	wrappedMetric Metric
+	prefix        string
+	labels        Labels
+}
+
+func (m *wrappingMetric) Desc() *Desc {
+	return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
+}
+
+func (m *wrappingMetric) Write(out *dto.Metric) error {
+	if err := m.wrappedMetric.Write(out); err != nil {
+		return err
+	}
+	if len(m.labels) == 0 {
+		// No wrapping labels.
+		return nil
+	}
+	for ln, lv := range m.labels {
+		out.Label = append(out.Label, &dto.LabelPair{
+			Name:  proto.String(ln),
+			Value: proto.String(lv),
+		})
+	}
+	sort.Sort(labelPairSorter(out.Label))
+	return nil
+}
+
+func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
+	constLabels := Labels{}
+	for _, lp := range desc.constLabelPairs {
+		constLabels[*lp.Name] = *lp.Value
+	}
+	for ln, lv := range labels {
+		if _, alreadyUsed := constLabels[ln]; alreadyUsed {
+			return &Desc{
+				fqName:          desc.fqName,
+				help:            desc.help,
+				variableLabels:  desc.variableLabels,
+				constLabelPairs: desc.constLabelPairs,
+				err:             fmt.Errorf("attempted wrapping with already existing label name %q", ln),
+			}
+		}
+		constLabels[ln] = lv
+	}
+	// NewDesc will do remaining validations.
+	newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
+	// Propagate errors if there was any. This will override any errer
+	// created by NewDesc above, i.e. earlier errors get precedence.
+	if desc.err != nil {
+		newDesc.err = desc.err
+	}
+	return newDesc
+}

vendor/github.com/prometheus/procfs/MAINTAINERS.md

@@ -1 +1,2 @@
-* Tobias Schmidt <tobidt@gmail.com>
+* Johannes 'fish' Ziemke <github@freigeist.org> @discordianfish
+* Paul Gier <pgier@redhat.com> @pgier

vendor/github.com/prometheus/procfs/Makefile

@@ -1,18 +1,29 @@
-ci: fmt lint test
+# Copyright 2018 The Prometheus Authors
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
-fmt:
-	! gofmt -l *.go | read nothing
-	go vet
+include Makefile.common
 
-lint:
-	go get github.com/golang/lint/golint
-	golint *.go
-
-test: sysfs/fixtures/.unpacked
-	go test -v ./...
-
-sysfs/fixtures/.unpacked: sysfs/fixtures.ttar
-	./ttar -C sysfs -x -f sysfs/fixtures.ttar
+%/.unpacked: %.ttar
+	@echo ">> extracting fixtures"
+	./ttar -C $(dir $*) -x -f $*.ttar
 	touch $@
 
-.PHONY: fmt lint test ci
+update_fixtures:
+	rm -vf fixtures/.unpacked
+	./ttar -c -f fixtures.ttar fixtures/
+
+.PHONY: build
+build:
+
+.PHONY: test
+test: fixtures/.unpacked common-test

vendor/github.com/prometheus/procfs/Makefile.common

@@ -0,0 +1,272 @@
+# Copyright 2018 The Prometheus Authors
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# A common Makefile that includes rules to be reused in different prometheus projects.
+# !!! Open PRs only against the prometheus/prometheus/Makefile.common repository!
+
+# Example usage :
+# Create the main Makefile in the root project directory.
+# include Makefile.common
+# customTarget:
+# 	@echo ">> Running customTarget"
+#
+
+# Ensure GOBIN is not set during build so that promu is installed to the correct path
+unexport GOBIN
+
+GO           ?= go
+GOFMT        ?= $(GO)fmt
+FIRST_GOPATH := $(firstword $(subst :, ,$(shell $(GO) env GOPATH)))
+GOOPTS       ?=
+GOHOSTOS     ?= $(shell $(GO) env GOHOSTOS)
+GOHOSTARCH   ?= $(shell $(GO) env GOHOSTARCH)
+
+GO_VERSION        ?= $(shell $(GO) version)
+GO_VERSION_NUMBER ?= $(word 3, $(GO_VERSION))
+PRE_GO_111        ?= $(shell echo $(GO_VERSION_NUMBER) | grep -E 'go1\.(10|[0-9])\.')
+
+GOVENDOR :=
+GO111MODULE :=
+ifeq (, $(PRE_GO_111))
+	ifneq (,$(wildcard go.mod))
+		# Enforce Go modules support just in case the directory is inside GOPATH (and for Travis CI).
+		GO111MODULE := on
+
+		ifneq (,$(wildcard vendor))
+			# Always use the local vendor/ directory to satisfy the dependencies.
+			GOOPTS := $(GOOPTS) -mod=vendor
+		endif
+	endif
+else
+	ifneq (,$(wildcard go.mod))
+		ifneq (,$(wildcard vendor))
+$(warning This repository requires Go >= 1.11 because of Go modules)
+$(warning Some recipes may not work as expected as the current Go runtime is '$(GO_VERSION_NUMBER)')
+		endif
+	else
+		# This repository isn't using Go modules (yet).
+		GOVENDOR := $(FIRST_GOPATH)/bin/govendor
+	endif
+endif
+PROMU        := $(FIRST_GOPATH)/bin/promu
+pkgs          = ./...
+
+ifeq (arm, $(GOHOSTARCH))
+	GOHOSTARM ?= $(shell GOARM= $(GO) env GOARM)
+	GO_BUILD_PLATFORM ?= $(GOHOSTOS)-$(GOHOSTARCH)v$(GOHOSTARM)
+else
+	GO_BUILD_PLATFORM ?= $(GOHOSTOS)-$(GOHOSTARCH)
+endif
+
+PROMU_VERSION ?= 0.4.0
+PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_VERSION)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM).tar.gz
+
+GOLANGCI_LINT :=
+GOLANGCI_LINT_OPTS ?=
+GOLANGCI_LINT_VERSION ?= v1.16.0
+# golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
+# windows isn't included here because of the path separator being different.
+ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))
+	ifeq ($(GOHOSTARCH),$(filter $(GOHOSTARCH),amd64 i386))
+		GOLANGCI_LINT := $(FIRST_GOPATH)/bin/golangci-lint
+	endif
+endif
+
+PREFIX                  ?= $(shell pwd)
+BIN_DIR                 ?= $(shell pwd)
+DOCKER_IMAGE_TAG        ?= $(subst /,-,$(shell git rev-parse --abbrev-ref HEAD))
+DOCKER_REPO             ?= prom
+
+DOCKER_ARCHS            ?= amd64
+
+BUILD_DOCKER_ARCHS = $(addprefix common-docker-,$(DOCKER_ARCHS))
+PUBLISH_DOCKER_ARCHS = $(addprefix common-docker-publish-,$(DOCKER_ARCHS))
+TAG_DOCKER_ARCHS = $(addprefix common-docker-tag-latest-,$(DOCKER_ARCHS))
+
+ifeq ($(GOHOSTARCH),amd64)
+        ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux freebsd darwin windows))
+                # Only supported on amd64
+                test-flags := -race
+        endif
+endif
+
+# This rule is used to forward a target like "build" to "common-build".  This
+# allows a new "build" target to be defined in a Makefile which includes this
+# one and override "common-build" without override warnings.
+%: common-% ;
+
+.PHONY: common-all
+common-all: precheck style check_license lint unused build test
+
+.PHONY: common-style
+common-style:
+	@echo ">> checking code style"
+	@fmtRes=$$($(GOFMT) -d $$(find . -path ./vendor -prune -o -name '*.go' -print)); \
+	if [ -n "$${fmtRes}" ]; then \
+		echo "gofmt checking failed!"; echo "$${fmtRes}"; echo; \
+		echo "Please ensure you are using $$($(GO) version) for formatting code."; \
+		exit 1; \
+	fi
+
+.PHONY: common-check_license
+common-check_license:
+	@echo ">> checking license header"
+	@licRes=$$(for file in $$(find . -type f -iname '*.go' ! -path './vendor/*') ; do \
+               awk 'NR<=3' $$file | grep -Eq "(Copyright|generated|GENERATED)" || echo $$file; \
+       done); \
+       if [ -n "$${licRes}" ]; then \
+               echo "license header checking failed:"; echo "$${licRes}"; \
+               exit 1; \
+       fi
+
+.PHONY: common-deps
+common-deps:
+	@echo ">> getting dependencies"
+ifdef GO111MODULE
+	GO111MODULE=$(GO111MODULE) $(GO) mod download
+else
+	$(GO) get $(GOOPTS) -t ./...
+endif
+
+.PHONY: common-test-short
+common-test-short:
+	@echo ">> running short tests"
+	GO111MODULE=$(GO111MODULE) $(GO) test -short $(GOOPTS) $(pkgs)
+
+.PHONY: common-test
+common-test:
+	@echo ">> running all tests"
+	GO111MODULE=$(GO111MODULE) $(GO) test $(test-flags) $(GOOPTS) $(pkgs)
+
+.PHONY: common-format
+common-format:
+	@echo ">> formatting code"
+	GO111MODULE=$(GO111MODULE) $(GO) fmt $(pkgs)
+
+.PHONY: common-vet
+common-vet:
+	@echo ">> vetting code"
+	GO111MODULE=$(GO111MODULE) $(GO) vet $(GOOPTS) $(pkgs)
+
+.PHONY: common-lint
+common-lint: $(GOLANGCI_LINT)
+ifdef GOLANGCI_LINT
+	@echo ">> running golangci-lint"
+ifdef GO111MODULE
+# 'go list' needs to be executed before staticcheck to prepopulate the modules cache.
+# Otherwise staticcheck might fail randomly for some reason not yet explained.
+	GO111MODULE=$(GO111MODULE) $(GO) list -e -compiled -test=true -export=false -deps=true -find=false -tags= -- ./... > /dev/null
+	GO111MODULE=$(GO111MODULE) $(GOLANGCI_LINT) run $(GOLANGCI_LINT_OPTS) $(pkgs)
+else
+	$(GOLANGCI_LINT) run $(pkgs)
+endif
+endif
+
+# For backward-compatibility.
+.PHONY: common-staticcheck
+common-staticcheck: lint
+
+.PHONY: common-unused
+common-unused: $(GOVENDOR)
+ifdef GOVENDOR
+	@echo ">> running check for unused packages"
+	@$(GOVENDOR) list +unused | grep . && exit 1 || echo 'No unused packages'
+else
+ifdef GO111MODULE
+	@echo ">> running check for unused/missing packages in go.mod"
+	GO111MODULE=$(GO111MODULE) $(GO) mod tidy
+ifeq (,$(wildcard vendor))
+	@git diff --exit-code -- go.sum go.mod
+else
+	@echo ">> running check for unused packages in vendor/"
+	GO111MODULE=$(GO111MODULE) $(GO) mod vendor
+	@git diff --exit-code -- go.sum go.mod vendor/
+endif
+endif
+endif
+
+.PHONY: common-build
+common-build: promu
+	@echo ">> building binaries"
+	GO111MODULE=$(GO111MODULE) $(PROMU) build --prefix $(PREFIX)
+
+.PHONY: common-tarball
+common-tarball: promu
+	@echo ">> building release tarball"
+	$(PROMU) tarball --prefix $(PREFIX) $(BIN_DIR)
+
+.PHONY: common-docker $(BUILD_DOCKER_ARCHS)
+common-docker: $(BUILD_DOCKER_ARCHS)
+$(BUILD_DOCKER_ARCHS): common-docker-%:
+	docker build -t "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)" \
+		--build-arg ARCH="$*" \
+		--build-arg OS="linux" \
+		.
+
+.PHONY: common-docker-publish $(PUBLISH_DOCKER_ARCHS)
+common-docker-publish: $(PUBLISH_DOCKER_ARCHS)
+$(PUBLISH_DOCKER_ARCHS): common-docker-publish-%:
+	docker push "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)"
+
+.PHONY: common-docker-tag-latest $(TAG_DOCKER_ARCHS)
+common-docker-tag-latest: $(TAG_DOCKER_ARCHS)
+$(TAG_DOCKER_ARCHS): common-docker-tag-latest-%:
+	docker tag "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)" "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:latest"
+
+.PHONY: common-docker-manifest
+common-docker-manifest:
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest create -a "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)" $(foreach ARCH,$(DOCKER_ARCHS),$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$(ARCH):$(DOCKER_IMAGE_TAG))
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest push "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)"
+
+.PHONY: promu
+promu: $(PROMU)
+
+$(PROMU):
+	$(eval PROMU_TMP := $(shell mktemp -d))
+	curl -s -L $(PROMU_URL) | tar -xvzf - -C $(PROMU_TMP)
+	mkdir -p $(FIRST_GOPATH)/bin
+	cp $(PROMU_TMP)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM)/promu $(FIRST_GOPATH)/bin/promu
+	rm -r $(PROMU_TMP)
+
+.PHONY: proto
+proto:
+	@echo ">> generating code from proto files"
+	@./scripts/genproto.sh
+
+ifdef GOLANGCI_LINT
+$(GOLANGCI_LINT):
+	mkdir -p $(FIRST_GOPATH)/bin
+	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(FIRST_GOPATH)/bin $(GOLANGCI_LINT_VERSION)
+endif
+
+ifdef GOVENDOR
+.PHONY: $(GOVENDOR)
+$(GOVENDOR):
+	GOOS= GOARCH= $(GO) get -u github.com/kardianos/govendor
+endif
+
+.PHONY: precheck
+precheck::
+
+define PRECHECK_COMMAND_template =
+precheck:: $(1)_precheck
+
+PRECHECK_COMMAND_$(1) ?= $(1) $$(strip $$(PRECHECK_OPTIONS_$(1)))
+.PHONY: $(1)_precheck
+$(1)_precheck:
+	@if ! $$(PRECHECK_COMMAND_$(1)) 1>/dev/null 2>&1; then \
+		echo "Execution of '$$(PRECHECK_COMMAND_$(1))' command failed. Is $(1) installed?"; \
+		exit 1; \
+	fi
+endef

vendor/github.com/prometheus/procfs/README.md

@@ -1,7 +1,7 @@
 # procfs
 
 This procfs package provides functions to retrieve system, kernel and process
-metrics from the pseudo-filesystem proc.
+metrics from the pseudo-filesystems /proc and /sys.
 
 *WARNING*: This package is a work in progress. Its API may still break in
 backwards-incompatible ways without warnings. Use it at your own risk.
@@ -9,3 +9,45 @@ backwards-incompatible ways without warnings. Use it at your own risk.
 [![GoDoc](https://godoc.org/github.com/prometheus/procfs?status.png)](https://godoc.org/github.com/prometheus/procfs)
 [![Build Status](https://travis-ci.org/prometheus/procfs.svg?branch=master)](https://travis-ci.org/prometheus/procfs)
 [![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/procfs)](https://goreportcard.com/report/github.com/prometheus/procfs)
+
+## Usage
+
+The procfs library is organized by packages based on whether the gathered data is coming from
+/proc, /sys, or both.  Each package contains an `FS` type which represents the path to either /proc, /sys, or both.  For example, current cpu statistics are gathered from
+`/proc/stat` and are available via the root procfs package.  First, the proc filesystem mount
+point is initialized, and then the stat information is read.
+
+```go
+fs, err := procfs.NewFS("/proc")
+stats, err := fs.Stat()
+```
+
+Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
+
+```go
+    fs, err := blockdevice.NewFS("/proc", "/sys")
+    stats, err := fs.ProcDiskstats()
+```
+
+## Building and Testing
+
+The procfs library is normally built as part of another application.  However, when making
+changes to the library, the `make test` command can be used to run the API test suite.
+
+### Updating Test Fixtures
+
+The procfs library includes a set of test fixtures which include many example files from
+the `/proc` and `/sys` filesystems.  These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
+which is extracted automatically during testing.  To add/update the test fixtures, first
+ensure the `fixtures` directory is up to date by removing the existing directory and then
+extracting the ttar file using `make fixtures/.unpacked` or just `make test`.
+
+```bash
+rm -rf fixtures
+make test
+```
+
+Next, make the required changes to the extracted files in the `fixtures` directory.  When
+the changes are complete, run `make update_fixtures` to create a new `fixtures.ttar` file
+based on the updated `fixtures` directory.  And finally, verify the changes using
+`git diff fixtures.ttar`.

vendor/github.com/prometheus/procfs/buddyinfo.go

@@ -31,19 +31,9 @@ type BuddyInfo struct {
 	Sizes []float64
 }
 
-// NewBuddyInfo reads the buddyinfo statistics.
-func NewBuddyInfo() ([]BuddyInfo, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.NewBuddyInfo()
-}
-
 // NewBuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
-func (fs FS) NewBuddyInfo() ([]BuddyInfo, error) {
-	file, err := os.Open(fs.Path("buddyinfo"))
+func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
+	file, err := os.Open(fs.proc.Path("buddyinfo"))
 	if err != nil {
 		return nil, err
 	}
@@ -62,7 +52,7 @@ func parseBuddyInfo(r io.Reader) ([]BuddyInfo, error) {
 	for scanner.Scan() {
 		var err error
 		line := scanner.Text()
-		parts := strings.Fields(string(line))
+		parts := strings.Fields(line)
 
 		if len(parts) < 4 {
 			return nil, fmt.Errorf("invalid number of fields when parsing buddyinfo")

vendor/github.com/prometheus/procfs/fs.go

@@ -1,46 +1,43 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
-	"fmt"
-	"os"
-	"path"
-
-	"github.com/prometheus/procfs/xfs"
+	"github.com/prometheus/procfs/internal/fs"
 )
 
-// FS represents the pseudo-filesystem proc, which provides an interface to
+// FS represents the pseudo-filesystem sys, which provides an interface to
 // kernel data structures.
-type FS string
+type FS struct {
+	proc fs.FS
+}
 
 // DefaultMountPoint is the common mount point of the proc filesystem.
-const DefaultMountPoint = "/proc"
+const DefaultMountPoint = fs.DefaultProcMountPoint
 
-// NewFS returns a new FS mounted under the given mountPoint. It will error
-// if the mount point can't be read.
+// NewDefaultFS returns a new proc FS mounted under the default proc mountPoint.
+// It will error if the mount point directory can't be read or is a file.
+func NewDefaultFS() (FS, error) {
+	return NewFS(DefaultMountPoint)
+}
+
+// NewFS returns a new proc FS mounted under the given proc mountPoint. It will error
+// if the mount point directory can't be read or is a file.
 func NewFS(mountPoint string) (FS, error) {
-	info, err := os.Stat(mountPoint)
+	fs, err := fs.NewFS(mountPoint)
 	if err != nil {
-		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
+		return FS{}, err
 	}
-	if !info.IsDir() {
-		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
-	}
-
-	return FS(mountPoint), nil
-}
-
-// Path returns the path of the given subsystem relative to the procfs root.
-func (fs FS) Path(p ...string) string {
-	return path.Join(append([]string{string(fs)}, p...)...)
-}
-
-// XFSStats retrieves XFS filesystem runtime statistics.
-func (fs FS) XFSStats() (*xfs.Stats, error) {
-	f, err := os.Open(fs.Path("fs/xfs/stat"))
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	return xfs.ParseStats(f)
+	return FS{fs}, nil
 }

vendor/github.com/prometheus/procfs/go.mod

@@ -0,0 +1,3 @@
+module github.com/prometheus/procfs
+
+require golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4

vendor/github.com/prometheus/procfs/go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4 h1:YUO/7uOKsKeq9UokNS62b8FYywz3ker1l1vDZRCRefw=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

vendor/github.com/prometheus/procfs/internal/fs/fs.go

@@ -0,0 +1,52 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+const (
+	// DefaultProcMountPoint is the common mount point of the proc filesystem.
+	DefaultProcMountPoint = "/proc"
+
+	// DefaultSysMountPoint is the common mount point of the sys filesystem.
+	DefaultSysMountPoint = "/sys"
+)
+
+// FS represents a pseudo-filesystem, normally /proc or /sys, which provides an
+// interface to kernel data structures.
+type FS string
+
+// NewFS returns a new FS mounted under the given mountPoint. It will error
+// if the mount point can't be read.
+func NewFS(mountPoint string) (FS, error) {
+	info, err := os.Stat(mountPoint)
+	if err != nil {
+		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
+	}
+	if !info.IsDir() {
+		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
+	}
+
+	return FS(mountPoint), nil
+}
+
+// Path appends the given path elements to the filesystem path, adding separators
+// as necessary.
+func (fs FS) Path(p ...string) string {
+	return filepath.Join(append([]string{string(fs)}, p...)...)
+}

vendor/github.com/prometheus/procfs/ipvs.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -31,16 +44,16 @@ type IPVSStats struct {
 type IPVSBackendStatus struct {
 	// The local (virtual) IP address.
 	LocalAddress net.IP
+	// The remote (real) IP address.
+	RemoteAddress net.IP
 	// The local (virtual) port.
 	LocalPort uint16
+	// The remote (real) port.
+	RemotePort uint16
 	// The local firewall mark
 	LocalMark string
 	// The transport protocol (TCP, UDP).
 	Proto string
-	// The remote (real) IP address.
-	RemoteAddress net.IP
-	// The remote (real) port.
-	RemotePort uint16
 	// The current number of active connections for this virtual/real address pair.
 	ActiveConn uint64
 	// The current number of inactive connections for this virtual/real address pair.
@@ -49,19 +62,9 @@ type IPVSBackendStatus struct {
 	Weight uint64
 }
 
-// NewIPVSStats reads the IPVS statistics.
-func NewIPVSStats() (IPVSStats, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return IPVSStats{}, err
-	}
-
-	return fs.NewIPVSStats()
-}
-
-// NewIPVSStats reads the IPVS statistics from the specified `proc` filesystem.
-func (fs FS) NewIPVSStats() (IPVSStats, error) {
-	file, err := os.Open(fs.Path("net/ip_vs_stats"))
+// IPVSStats reads the IPVS statistics from the specified `proc` filesystem.
+func (fs FS) IPVSStats() (IPVSStats, error) {
+	file, err := os.Open(fs.proc.Path("net/ip_vs_stats"))
 	if err != nil {
 		return IPVSStats{}, err
 	}
@@ -118,19 +121,9 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 	return stats, nil
 }
 
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs.
-func NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return []IPVSBackendStatus{}, err
-	}
-
-	return fs.NewIPVSBackendStatus()
-}
-
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
-func (fs FS) NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	file, err := os.Open(fs.Path("net/ip_vs"))
+// IPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
+func (fs FS) IPVSBackendStatus() ([]IPVSBackendStatus, error) {
+	file, err := os.Open(fs.proc.Path("net/ip_vs"))
 	if err != nil {
 		return nil, err
 	}
@@ -151,7 +144,7 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 	)
 
 	for scanner.Scan() {
-		fields := strings.Fields(string(scanner.Text()))
+		fields := strings.Fields(scanner.Text())
 		if len(fields) == 0 {
 			continue
 		}

vendor/github.com/prometheus/procfs/mdstat.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -29,64 +42,64 @@ type MDStat struct {
 	BlocksSynced int64
 }
 
-// ParseMDStat parses an mdstat-file and returns a struct with the relevant infos.
-func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
-	mdStatusFilePath := fs.Path("mdstat")
-	content, err := ioutil.ReadFile(mdStatusFilePath)
+// MDStat parses an mdstat-file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.  More information available here:
+// https://raid.wiki.kernel.org/index.php/Mdstat
+func (fs FS) MDStat() ([]MDStat, error) {
+	data, err := ioutil.ReadFile(fs.proc.Path("mdstat"))
 	if err != nil {
-		return []MDStat{}, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+		return nil, fmt.Errorf("error parsing mdstat %s: %s", fs.proc.Path("mdstat"), err)
 	}
+	mdstat, err := parseMDStat(data)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing mdstat %s: %s", fs.proc.Path("mdstat"), err)
+	}
+	return mdstat, nil
+}
 
-	mdStates := []MDStat{}
-	lines := strings.Split(string(content), "\n")
+// parseMDStat parses data from mdstat file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.
+func parseMDStat(mdstatData []byte) ([]MDStat, error) {
+	mdStats := []MDStat{}
+	lines := strings.Split(string(mdstatData), "\n")
 	for i, l := range lines {
-		if l == "" {
-			continue
-		}
-		if l[0] == ' ' {
-			continue
-		}
-		if strings.HasPrefix(l, "Personalities") || strings.HasPrefix(l, "unused") {
+		if strings.TrimSpace(l) == "" || l[0] == ' ' ||
+			strings.HasPrefix(l, "Personalities") || strings.HasPrefix(l, "unused") {
 			continue
 		}
 
-		mainLine := strings.Split(l, " ")
-		if len(mainLine) < 3 {
-			return mdStates, fmt.Errorf("error parsing mdline: %s", l)
+		deviceFields := strings.Fields(l)
+		if len(deviceFields) < 3 {
+			return nil, fmt.Errorf("not enough fields in mdline (expected at least 3): %s", l)
 		}
-		mdName := mainLine[0]
-		activityState := mainLine[2]
+		mdName := deviceFields[0]
+		activityState := deviceFields[2]
 
 		if len(lines) <= i+3 {
-			return mdStates, fmt.Errorf(
-				"error parsing %s: too few lines for md device %s",
-				mdStatusFilePath,
-				mdName,
-			)
+			return mdStats, fmt.Errorf("missing lines for md device %s", mdName)
 		}
 
-		active, total, size, err := evalStatusline(lines[i+1])
+		active, total, size, err := evalStatusLine(lines[i+1])
 		if err != nil {
-			return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+			return nil, err
 		}
 
-		// j is the line number of the syncing-line.
-		j := i + 2
+		syncLineIdx := i + 2
 		if strings.Contains(lines[i+2], "bitmap") { // skip bitmap line
-			j = i + 3
+			syncLineIdx++
 		}
 
-		// If device is syncing at the moment, get the number of currently
+		// If device is recovering/syncing at the moment, get the number of currently
 		// synced bytes, otherwise that number equals the size of the device.
 		syncedBlocks := size
-		if strings.Contains(lines[j], "recovery") || strings.Contains(lines[j], "resync") {
-			syncedBlocks, err = evalBuildline(lines[j])
+		if strings.Contains(lines[syncLineIdx], "recovery") || strings.Contains(lines[syncLineIdx], "resync") {
+			syncedBlocks, err = evalRecoveryLine(lines[syncLineIdx])
 			if err != nil {
-				return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+				return nil, err
 			}
 		}
 
-		mdStates = append(mdStates, MDStat{
+		mdStats = append(mdStats, MDStat{
 			Name:          mdName,
 			ActivityState: activityState,
 			DisksActive:   active,
@@ -96,10 +109,10 @@ func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
 		})
 	}
 
-	return mdStates, nil
+	return mdStats, nil
 }
 
-func evalStatusline(statusline string) (active, total, size int64, err error) {
+func evalStatusLine(statusline string) (active, total, size int64, err error) {
 	matches := statuslineRE.FindStringSubmatch(statusline)
 	if len(matches) != 4 {
 		return 0, 0, 0, fmt.Errorf("unexpected statusline: %s", statusline)
@@ -123,7 +136,7 @@ func evalStatusline(statusline string) (active, total, size int64, err error) {
 	return active, total, size, nil
 }
 
-func evalBuildline(buildline string) (syncedBlocks int64, err error) {
+func evalRecoveryLine(buildline string) (syncedBlocks int64, err error) {
 	matches := buildlineRE.FindStringSubmatch(buildline)
 	if len(matches) != 2 {
 		return 0, fmt.Errorf("unexpected buildline: %s", buildline)

vendor/github.com/prometheus/procfs/mountstats.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 // While implementing parsing of /proc/[pid]/mountstats, this blog was used
@@ -26,8 +39,11 @@ const (
 	statVersion10 = "1.0"
 	statVersion11 = "1.1"
 
-	fieldTransport10Len = 10
-	fieldTransport11Len = 13
+	fieldTransport10TCPLen = 10
+	fieldTransport10UDPLen = 7
+
+	fieldTransport11TCPLen = 13
+	fieldTransport11UDPLen = 10
 )
 
 // A Mount is a device mount parsed from /proc/[pid]/mountstats.
@@ -53,6 +69,8 @@ type MountStats interface {
 type MountStatsNFS struct {
 	// The version of statistics provided.
 	StatVersion string
+	// The mount options of the NFS mount.
+	Opts map[string]string
 	// The age of the NFS mount.
 	Age time.Duration
 	// Statistics related to byte counters for various operations.
@@ -163,16 +181,18 @@ type NFSOperationStats struct {
 	// Number of bytes received for this operation, including RPC headers and payload.
 	BytesReceived uint64
 	// Duration all requests spent queued for transmission before they were sent.
-	CumulativeQueueTime time.Duration
+	CumulativeQueueMilliseconds uint64
 	// Duration it took to get a reply back after the request was transmitted.
-	CumulativeTotalResponseTime time.Duration
+	CumulativeTotalResponseMilliseconds uint64
 	// Duration from when a request was enqueued to when it was completely handled.
-	CumulativeTotalRequestTime time.Duration
+	CumulativeTotalRequestMilliseconds uint64
 }
 
 // A NFSTransportStats contains statistics for the NFS mount RPC requests and
 // responses.
 type NFSTransportStats struct {
+	// The transport protocol used for the NFS mount.
+	Protocol string
 	// The local port used for the NFS mount.
 	Port uint64
 	// Number of times the client has had to establish a connection from scratch
@@ -184,7 +204,7 @@ type NFSTransportStats struct {
 	// spent waiting for connections to the server to be established.
 	ConnectIdleTime uint64
 	// Duration since the NFS mount last saw any RPC traffic.
-	IdleTime time.Duration
+	IdleTimeSeconds uint64
 	// Number of RPC requests for this mount sent to the NFS server.
 	Sends uint64
 	// Number of RPC responses for this mount received from the NFS server.
@@ -299,6 +319,7 @@ func parseMount(ss []string) (*Mount, error) {
 func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, error) {
 	// Field indicators for parsing specific types of data
 	const (
+		fieldOpts       = "opts:"
 		fieldAge        = "age:"
 		fieldBytes      = "bytes:"
 		fieldEvents     = "events:"
@@ -320,6 +341,18 @@ func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, e
 		}
 
 		switch ss[0] {
+		case fieldOpts:
+			if stats.Opts == nil {
+				stats.Opts = map[string]string{}
+			}
+			for _, opt := range strings.Split(ss[1], ",") {
+				split := strings.Split(opt, "=")
+				if len(split) == 2 {
+					stats.Opts[split[0]] = split[1]
+				} else {
+					stats.Opts[opt] = ""
+				}
+			}
 		case fieldAge:
 			// Age integer is in seconds
 			d, err := time.ParseDuration(ss[1] + "s")
@@ -347,7 +380,7 @@ func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, e
 				return nil, fmt.Errorf("not enough information for NFS transport stats: %v", ss)
 			}
 
-			tstats, err := parseNFSTransportStats(ss[2:], statVersion)
+			tstats, err := parseNFSTransportStats(ss[1:], statVersion)
 			if err != nil {
 				return nil, err
 			}
@@ -491,15 +524,15 @@ func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) {
 		}
 
 		ops = append(ops, NFSOperationStats{
-			Operation:                   strings.TrimSuffix(ss[0], ":"),
-			Requests:                    ns[0],
-			Transmissions:               ns[1],
-			MajorTimeouts:               ns[2],
-			BytesSent:                   ns[3],
-			BytesReceived:               ns[4],
-			CumulativeQueueTime:         time.Duration(ns[5]) * time.Millisecond,
-			CumulativeTotalResponseTime: time.Duration(ns[6]) * time.Millisecond,
-			CumulativeTotalRequestTime:  time.Duration(ns[7]) * time.Millisecond,
+			Operation:                           strings.TrimSuffix(ss[0], ":"),
+			Requests:                            ns[0],
+			Transmissions:                       ns[1],
+			MajorTimeouts:                       ns[2],
+			BytesSent:                           ns[3],
+			BytesReceived:                       ns[4],
+			CumulativeQueueMilliseconds:         ns[5],
+			CumulativeTotalResponseMilliseconds: ns[6],
+			CumulativeTotalRequestMilliseconds:  ns[7],
 		})
 	}
 
@@ -509,13 +542,33 @@ func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) {
 // parseNFSTransportStats parses a NFSTransportStats line using an input set of
 // integer fields matched to a specific stats version.
 func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats, error) {
+	// Extract the protocol field. It is the only string value in the line
+	protocol := ss[0]
+	ss = ss[1:]
+
 	switch statVersion {
 	case statVersion10:
-		if len(ss) != fieldTransport10Len {
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport10TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport10UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.0 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
 			return nil, fmt.Errorf("invalid NFS transport stats 1.0 statement: %v", ss)
 		}
 	case statVersion11:
-		if len(ss) != fieldTransport11Len {
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport11TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport11UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.1 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
 			return nil, fmt.Errorf("invalid NFS transport stats 1.1 statement: %v", ss)
 		}
 	default:
@@ -523,12 +576,13 @@ func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats
 	}
 
 	// Allocate enough for v1.1 stats since zero value for v1.1 stats will be okay
-	// in a v1.0 response.
+	// in a v1.0 response. Since the stat length is bigger for TCP stats, we use
+	// the TCP length here.
 	//
 	// Note: slice length must be set to length of v1.1 stats to avoid a panic when
 	// only v1.0 stats are present.
 	// See: https://github.com/prometheus/node_exporter/issues/571.
-	ns := make([]uint64, fieldTransport11Len)
+	ns := make([]uint64, fieldTransport11TCPLen)
 	for i, s := range ss {
 		n, err := strconv.ParseUint(s, 10, 64)
 		if err != nil {
@@ -538,12 +592,23 @@ func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats
 		ns[i] = n
 	}
 
+	// The fields differ depending on the transport protocol (TCP or UDP)
+	// From https://utcc.utoronto.ca/%7Ecks/space/blog/linux/NFSMountstatsXprt
+	//
+	// For the udp RPC transport there is no connection count, connect idle time,
+	// or idle time (fields #3, #4, and #5); all other fields are the same. So
+	// we set them to 0 here.
+	if protocol == "udp" {
+		ns = append(ns[:2], append(make([]uint64, 3), ns[2:]...)...)
+	}
+
 	return &NFSTransportStats{
+		Protocol:                 protocol,
 		Port:                     ns[0],
 		Bind:                     ns[1],
 		Connect:                  ns[2],
 		ConnectIdleTime:          ns[3],
-		IdleTime:                 time.Duration(ns[4]) * time.Second,
+		IdleTimeSeconds:          ns[4],
 		Sends:                    ns[5],
 		Receives:                 ns[6],
 		BadTransactionIDs:        ns[7],

vendor/github.com/prometheus/procfs/net_dev.go

@@ -0,0 +1,206 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// NetDevLine is single line parsed from /proc/net/dev or /proc/[pid]/net/dev.
+type NetDevLine struct {
+	Name         string `json:"name"`          // The name of the interface.
+	RxBytes      uint64 `json:"rx_bytes"`      // Cumulative count of bytes received.
+	RxPackets    uint64 `json:"rx_packets"`    // Cumulative count of packets received.
+	RxErrors     uint64 `json:"rx_errors"`     // Cumulative count of receive errors encountered.
+	RxDropped    uint64 `json:"rx_dropped"`    // Cumulative count of packets dropped while receiving.
+	RxFIFO       uint64 `json:"rx_fifo"`       // Cumulative count of FIFO buffer errors.
+	RxFrame      uint64 `json:"rx_frame"`      // Cumulative count of packet framing errors.
+	RxCompressed uint64 `json:"rx_compressed"` // Cumulative count of compressed packets received by the device driver.
+	RxMulticast  uint64 `json:"rx_multicast"`  // Cumulative count of multicast frames received by the device driver.
+	TxBytes      uint64 `json:"tx_bytes"`      // Cumulative count of bytes transmitted.
+	TxPackets    uint64 `json:"tx_packets"`    // Cumulative count of packets transmitted.
+	TxErrors     uint64 `json:"tx_errors"`     // Cumulative count of transmit errors encountered.
+	TxDropped    uint64 `json:"tx_dropped"`    // Cumulative count of packets dropped while transmitting.
+	TxFIFO       uint64 `json:"tx_fifo"`       // Cumulative count of FIFO buffer errors.
+	TxCollisions uint64 `json:"tx_collisions"` // Cumulative count of collisions detected on the interface.
+	TxCarrier    uint64 `json:"tx_carrier"`    // Cumulative count of carrier losses detected by the device driver.
+	TxCompressed uint64 `json:"tx_compressed"` // Cumulative count of compressed packets transmitted by the device driver.
+}
+
+// NetDev is parsed from /proc/net/dev or /proc/[pid]/net/dev. The map keys
+// are interface names.
+type NetDev map[string]NetDevLine
+
+// NetDev returns kernel/system statistics read from /proc/net/dev.
+func (fs FS) NetDev() (NetDev, error) {
+	return newNetDev(fs.proc.Path("net/dev"))
+}
+
+// NetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
+func (p Proc) NetDev() (NetDev, error) {
+	return newNetDev(p.path("net/dev"))
+}
+
+// newNetDev creates a new NetDev from the contents of the given file.
+func newNetDev(file string) (NetDev, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return NetDev{}, err
+	}
+	defer f.Close()
+
+	netDev := NetDev{}
+	s := bufio.NewScanner(f)
+	for n := 0; s.Scan(); n++ {
+		// Skip the 2 header lines.
+		if n < 2 {
+			continue
+		}
+
+		line, err := netDev.parseLine(s.Text())
+		if err != nil {
+			return netDev, err
+		}
+
+		netDev[line.Name] = *line
+	}
+
+	return netDev, s.Err()
+}
+
+// parseLine parses a single line from the /proc/net/dev file. Header lines
+// must be filtered prior to calling this method.
+func (netDev NetDev) parseLine(rawLine string) (*NetDevLine, error) {
+	parts := strings.SplitN(rawLine, ":", 2)
+	if len(parts) != 2 {
+		return nil, errors.New("invalid net/dev line, missing colon")
+	}
+	fields := strings.Fields(strings.TrimSpace(parts[1]))
+
+	var err error
+	line := &NetDevLine{}
+
+	// Interface Name
+	line.Name = strings.TrimSpace(parts[0])
+	if line.Name == "" {
+		return nil, errors.New("invalid net/dev line, empty interface name")
+	}
+
+	// RX
+	line.RxBytes, err = strconv.ParseUint(fields[0], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxPackets, err = strconv.ParseUint(fields[1], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxErrors, err = strconv.ParseUint(fields[2], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxDropped, err = strconv.ParseUint(fields[3], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxFIFO, err = strconv.ParseUint(fields[4], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxFrame, err = strconv.ParseUint(fields[5], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxCompressed, err = strconv.ParseUint(fields[6], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxMulticast, err = strconv.ParseUint(fields[7], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	// TX
+	line.TxBytes, err = strconv.ParseUint(fields[8], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxPackets, err = strconv.ParseUint(fields[9], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxErrors, err = strconv.ParseUint(fields[10], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxDropped, err = strconv.ParseUint(fields[11], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxFIFO, err = strconv.ParseUint(fields[12], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCollisions, err = strconv.ParseUint(fields[13], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCarrier, err = strconv.ParseUint(fields[14], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCompressed, err = strconv.ParseUint(fields[15], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	return line, nil
+}
+
+// Total aggregates the values across interfaces and returns a new NetDevLine.
+// The Name field will be a sorted comma separated list of interface names.
+func (netDev NetDev) Total() NetDevLine {
+	total := NetDevLine{}
+
+	names := make([]string, 0, len(netDev))
+	for _, ifc := range netDev {
+		names = append(names, ifc.Name)
+		total.RxBytes += ifc.RxBytes
+		total.RxPackets += ifc.RxPackets
+		total.RxPackets += ifc.RxPackets
+		total.RxErrors += ifc.RxErrors
+		total.RxDropped += ifc.RxDropped
+		total.RxFIFO += ifc.RxFIFO
+		total.RxFrame += ifc.RxFrame
+		total.RxCompressed += ifc.RxCompressed
+		total.RxMulticast += ifc.RxMulticast
+		total.TxBytes += ifc.TxBytes
+		total.TxPackets += ifc.TxPackets
+		total.TxErrors += ifc.TxErrors
+		total.TxDropped += ifc.TxDropped
+		total.TxFIFO += ifc.TxFIFO
+		total.TxCollisions += ifc.TxCollisions
+		total.TxCarrier += ifc.TxCarrier
+		total.TxCompressed += ifc.TxCompressed
+	}
+	sort.Strings(names)
+	total.Name = strings.Join(names, ", ")
+
+	return total
+}

vendor/github.com/prometheus/procfs/net_unix.go

@@ -0,0 +1,275 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// For the proc file format details,
+// see https://elixir.bootlin.com/linux/v4.17/source/net/unix/af_unix.c#L2815
+// and https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/net.h#L48.
+
+const (
+	netUnixKernelPtrIdx = iota
+	netUnixRefCountIdx
+	_
+	netUnixFlagsIdx
+	netUnixTypeIdx
+	netUnixStateIdx
+	netUnixInodeIdx
+
+	// Inode and Path are optional.
+	netUnixStaticFieldsCnt = 6
+)
+
+const (
+	netUnixTypeStream    = 1
+	netUnixTypeDgram     = 2
+	netUnixTypeSeqpacket = 5
+
+	netUnixFlagListen = 1 << 16
+
+	netUnixStateUnconnected  = 1
+	netUnixStateConnecting   = 2
+	netUnixStateConnected    = 3
+	netUnixStateDisconnected = 4
+)
+
+var errInvalidKernelPtrFmt = errors.New("Invalid Num(the kernel table slot number) format")
+
+// NetUnixType is the type of the type field.
+type NetUnixType uint64
+
+// NetUnixFlags is the type of the flags field.
+type NetUnixFlags uint64
+
+// NetUnixState is the type of the state field.
+type NetUnixState uint64
+
+// NetUnixLine represents a line of /proc/net/unix.
+type NetUnixLine struct {
+	KernelPtr string
+	RefCount  uint64
+	Protocol  uint64
+	Flags     NetUnixFlags
+	Type      NetUnixType
+	State     NetUnixState
+	Inode     uint64
+	Path      string
+}
+
+// NetUnix holds the data read from /proc/net/unix.
+type NetUnix struct {
+	Rows []*NetUnixLine
+}
+
+// NewNetUnix returns data read from /proc/net/unix.
+func NewNetUnix() (*NetUnix, error) {
+	fs, err := NewFS(DefaultMountPoint)
+	if err != nil {
+		return nil, err
+	}
+
+	return fs.NewNetUnix()
+}
+
+// NewNetUnix returns data read from /proc/net/unix.
+func (fs FS) NewNetUnix() (*NetUnix, error) {
+	return NewNetUnixByPath(fs.proc.Path("net/unix"))
+}
+
+// NewNetUnixByPath returns data read from /proc/net/unix by file path.
+// It might returns an error with partial parsed data, if an error occur after some data parsed.
+func NewNetUnixByPath(path string) (*NetUnix, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return NewNetUnixByReader(f)
+}
+
+// NewNetUnixByReader returns data read from /proc/net/unix by a reader.
+// It might returns an error with partial parsed data, if an error occur after some data parsed.
+func NewNetUnixByReader(reader io.Reader) (*NetUnix, error) {
+	nu := &NetUnix{
+		Rows: make([]*NetUnixLine, 0, 32),
+	}
+	scanner := bufio.NewScanner(reader)
+	// Omit the header line.
+	scanner.Scan()
+	header := scanner.Text()
+	// From the man page of proc(5), it does not contain an Inode field,
+	// but in actually it exists.
+	// This code works for both cases.
+	hasInode := strings.Contains(header, "Inode")
+
+	minFieldsCnt := netUnixStaticFieldsCnt
+	if hasInode {
+		minFieldsCnt++
+	}
+	for scanner.Scan() {
+		line := scanner.Text()
+		item, err := nu.parseLine(line, hasInode, minFieldsCnt)
+		if err != nil {
+			return nu, err
+		}
+		nu.Rows = append(nu.Rows, item)
+	}
+
+	return nu, scanner.Err()
+}
+
+func (u *NetUnix) parseLine(line string, hasInode bool, minFieldsCnt int) (*NetUnixLine, error) {
+	fields := strings.Fields(line)
+	fieldsLen := len(fields)
+	if fieldsLen < minFieldsCnt {
+		return nil, fmt.Errorf(
+			"Parse Unix domain failed: expect at least %d fields but got %d",
+			minFieldsCnt, fieldsLen)
+	}
+	kernelPtr, err := u.parseKernelPtr(fields[netUnixKernelPtrIdx])
+	if err != nil {
+		return nil, fmt.Errorf("Parse Unix domain num(%s) failed: %s", fields[netUnixKernelPtrIdx], err)
+	}
+	users, err := u.parseUsers(fields[netUnixRefCountIdx])
+	if err != nil {
+		return nil, fmt.Errorf("Parse Unix domain ref count(%s) failed: %s", fields[netUnixRefCountIdx], err)
+	}
+	flags, err := u.parseFlags(fields[netUnixFlagsIdx])
+	if err != nil {
+		return nil, fmt.Errorf("Parse Unix domain flags(%s) failed: %s", fields[netUnixFlagsIdx], err)
+	}
+	typ, err := u.parseType(fields[netUnixTypeIdx])
+	if err != nil {
+		return nil, fmt.Errorf("Parse Unix domain type(%s) failed: %s", fields[netUnixTypeIdx], err)
+	}
+	state, err := u.parseState(fields[netUnixStateIdx])
+	if err != nil {
+		return nil, fmt.Errorf("Parse Unix domain state(%s) failed: %s", fields[netUnixStateIdx], err)
+	}
+	var inode uint64
+	if hasInode {
+		inodeStr := fields[netUnixInodeIdx]
+		inode, err = u.parseInode(inodeStr)
+		if err != nil {
+			return nil, fmt.Errorf("Parse Unix domain inode(%s) failed: %s", inodeStr, err)
+		}
+	}
+
+	nuLine := &NetUnixLine{
+		KernelPtr: kernelPtr,
+		RefCount:  users,
+		Type:      typ,
+		Flags:     flags,
+		State:     state,
+		Inode:     inode,
+	}
+
+	// Path field is optional.
+	if fieldsLen > minFieldsCnt {
+		pathIdx := netUnixInodeIdx + 1
+		if !hasInode {
+			pathIdx--
+		}
+		nuLine.Path = fields[pathIdx]
+	}
+
+	return nuLine, nil
+}
+
+func (u NetUnix) parseKernelPtr(str string) (string, error) {
+	if !strings.HasSuffix(str, ":") {
+		return "", errInvalidKernelPtrFmt
+	}
+	return str[:len(str)-1], nil
+}
+
+func (u NetUnix) parseUsers(hexStr string) (uint64, error) {
+	return strconv.ParseUint(hexStr, 16, 32)
+}
+
+func (u NetUnix) parseProtocol(hexStr string) (uint64, error) {
+	return strconv.ParseUint(hexStr, 16, 32)
+}
+
+func (u NetUnix) parseType(hexStr string) (NetUnixType, error) {
+	typ, err := strconv.ParseUint(hexStr, 16, 16)
+	if err != nil {
+		return 0, err
+	}
+	return NetUnixType(typ), nil
+}
+
+func (u NetUnix) parseFlags(hexStr string) (NetUnixFlags, error) {
+	flags, err := strconv.ParseUint(hexStr, 16, 32)
+	if err != nil {
+		return 0, err
+	}
+	return NetUnixFlags(flags), nil
+}
+
+func (u NetUnix) parseState(hexStr string) (NetUnixState, error) {
+	st, err := strconv.ParseInt(hexStr, 16, 8)
+	if err != nil {
+		return 0, err
+	}
+	return NetUnixState(st), nil
+}
+
+func (u NetUnix) parseInode(inodeStr string) (uint64, error) {
+	return strconv.ParseUint(inodeStr, 10, 64)
+}
+
+func (t NetUnixType) String() string {
+	switch t {
+	case netUnixTypeStream:
+		return "stream"
+	case netUnixTypeDgram:
+		return "dgram"
+	case netUnixTypeSeqpacket:
+		return "seqpacket"
+	}
+	return "unknown"
+}
+
+func (f NetUnixFlags) String() string {
+	switch f {
+	case netUnixFlagListen:
+		return "listen"
+	default:
+		return "default"
+	}
+}
+
+func (s NetUnixState) String() string {
+	switch s {
+	case netUnixStateUnconnected:
+		return "unconnected"
+	case netUnixStateConnecting:
+		return "connecting"
+	case netUnixStateConnected:
+		return "connected"
+	case netUnixStateDisconnected:
+		return "disconnected"
+	}
+	return "unknown"
+}

vendor/github.com/prometheus/procfs/proc.go

@@ -1,11 +1,27 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
+	"bytes"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
+
+	"github.com/prometheus/procfs/internal/fs"
 )
 
 // Proc provides information about a running process.
@@ -13,7 +29,7 @@ type Proc struct {
 	// The process ID.
 	PID int
 
-	fs FS
+	fs fs.FS
 }
 
 // Procs represents a list of Proc structs.
@@ -38,7 +54,7 @@ func NewProc(pid int) (Proc, error) {
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
 // AllProcs returns a list of all currently available processes under /proc.
@@ -52,28 +68,35 @@ func AllProcs() (Procs, error) {
 
 // Self returns a process for the current process.
 func (fs FS) Self() (Proc, error) {
-	p, err := os.Readlink(fs.Path("self"))
+	p, err := os.Readlink(fs.proc.Path("self"))
 	if err != nil {
 		return Proc{}, err
 	}
-	pid, err := strconv.Atoi(strings.Replace(p, string(fs), "", -1))
+	pid, err := strconv.Atoi(strings.Replace(p, string(fs.proc), "", -1))
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
 // NewProc returns a process for the given pid.
+//
+// Deprecated: use fs.Proc() instead
 func (fs FS) NewProc(pid int) (Proc, error) {
-	if _, err := os.Stat(fs.Path(strconv.Itoa(pid))); err != nil {
+	return fs.Proc(pid)
+}
+
+// Proc returns a process for the given pid.
+func (fs FS) Proc(pid int) (Proc, error) {
+	if _, err := os.Stat(fs.proc.Path(strconv.Itoa(pid))); err != nil {
 		return Proc{}, err
 	}
-	return Proc{PID: pid, fs: fs}, nil
+	return Proc{PID: pid, fs: fs.proc}, nil
 }
 
 // AllProcs returns a list of all currently available processes.
 func (fs FS) AllProcs() (Procs, error) {
-	d, err := os.Open(fs.Path())
+	d, err := os.Open(fs.proc.Path())
 	if err != nil {
 		return Procs{}, err
 	}
@@ -90,7 +113,7 @@ func (fs FS) AllProcs() (Procs, error) {
 		if err != nil {
 			continue
 		}
-		p = append(p, Proc{PID: int(pid), fs: fs})
+		p = append(p, Proc{PID: int(pid), fs: fs.proc})
 	}
 
 	return p, nil
@@ -113,7 +136,7 @@ func (p Proc) CmdLine() ([]string, error) {
 		return []string{}, nil
 	}
 
-	return strings.Split(string(data[:len(data)-1]), string(byte(0))), nil
+	return strings.Split(string(bytes.TrimRight(data, string("\x00"))), string(byte(0))), nil
 }
 
 // Comm returns the command name of a process.
@@ -142,6 +165,26 @@ func (p Proc) Executable() (string, error) {
 	return exe, err
 }
 
+// Cwd returns the absolute path to the current working directory of the process.
+func (p Proc) Cwd() (string, error) {
+	wd, err := os.Readlink(p.path("cwd"))
+	if os.IsNotExist(err) {
+		return "", nil
+	}
+
+	return wd, err
+}
+
+// RootDir returns the absolute path to the process's root directory (as set by chroot)
+func (p Proc) RootDir() (string, error) {
+	rdir, err := os.Readlink(p.path("root"))
+	if os.IsNotExist(err) {
+		return "", nil
+	}
+
+	return rdir, err
+}
+
 // FileDescriptors returns the currently open file descriptors of a process.
 func (p Proc) FileDescriptors() ([]uintptr, error) {
 	names, err := p.fileDescriptors()

vendor/github.com/prometheus/procfs/proc_io.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -26,8 +39,8 @@ type ProcIO struct {
 	CancelledWriteBytes int64
 }
 
-// NewIO creates a new ProcIO instance from a given Proc instance.
-func (p Proc) NewIO() (ProcIO, error) {
+// IO creates a new ProcIO instance from a given Proc instance.
+func (p Proc) IO() (ProcIO, error) {
 	pio := ProcIO{}
 
 	f, err := os.Open(p.path("io"))
@@ -47,9 +60,6 @@ func (p Proc) NewIO() (ProcIO, error) {
 
 	_, err = fmt.Sscanf(string(data), ioFormat, &pio.RChar, &pio.WChar, &pio.SyscR,
 		&pio.SyscW, &pio.ReadBytes, &pio.WriteBytes, &pio.CancelledWriteBytes)
-	if err != nil {
-		return pio, err
-	}
 
-	return pio, nil
+	return pio, err
 }

vendor/github.com/prometheus/procfs/proc_limits.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -13,46 +26,46 @@ import (
 // http://man7.org/linux/man-pages/man2/getrlimit.2.html.
 type ProcLimits struct {
 	// CPU time limit in seconds.
-	CPUTime int
+	CPUTime int64
 	// Maximum size of files that the process may create.
-	FileSize int
+	FileSize int64
 	// Maximum size of the process's data segment (initialized data,
 	// uninitialized data, and heap).
-	DataSize int
+	DataSize int64
 	// Maximum size of the process stack in bytes.
-	StackSize int
+	StackSize int64
 	// Maximum size of a core file.
-	CoreFileSize int
+	CoreFileSize int64
 	// Limit of the process's resident set in pages.
-	ResidentSet int
+	ResidentSet int64
 	// Maximum number of processes that can be created for the real user ID of
 	// the calling process.
-	Processes int
+	Processes int64
 	// Value one greater than the maximum file descriptor number that can be
 	// opened by this process.
-	OpenFiles int
+	OpenFiles int64
 	// Maximum number of bytes of memory that may be locked into RAM.
-	LockedMemory int
+	LockedMemory int64
 	// Maximum size of the process's virtual memory address space in bytes.
-	AddressSpace int
+	AddressSpace int64
 	// Limit on the combined number of flock(2) locks and fcntl(2) leases that
 	// this process may establish.
-	FileLocks int
+	FileLocks int64
 	// Limit of signals that may be queued for the real user ID of the calling
 	// process.
-	PendingSignals int
+	PendingSignals int64
 	// Limit on the number of bytes that can be allocated for POSIX message
 	// queues for the real user ID of the calling process.
-	MsqqueueSize int
+	MsqqueueSize int64
 	// Limit of the nice priority set using setpriority(2) or nice(2).
-	NicePriority int
+	NicePriority int64
 	// Limit of the real-time priority set using sched_setscheduler(2) or
 	// sched_setparam(2).
-	RealtimePriority int
+	RealtimePriority int64
 	// Limit (in microseconds) on the amount of CPU time that a process
 	// scheduled under a real-time scheduling policy may consume without making
 	// a blocking system call.
-	RealtimeTimeout int
+	RealtimeTimeout int64
 }
 
 const (
@@ -65,7 +78,14 @@ var (
 )
 
 // NewLimits returns the current soft limits of the process.
+//
+// Deprecated: use p.Limits() instead
 func (p Proc) NewLimits() (ProcLimits, error) {
+	return p.Limits()
+}
+
+// Limits returns the current soft limits of the process.
+func (p Proc) Limits() (ProcLimits, error) {
 	f, err := os.Open(p.path("limits"))
 	if err != nil {
 		return ProcLimits{}, err
@@ -125,13 +145,13 @@ func (p Proc) NewLimits() (ProcLimits, error) {
 	return l, s.Err()
 }
 
-func parseInt(s string) (int, error) {
+func parseInt(s string) (int64, error) {
 	if s == limitsUnlimited {
 		return -1, nil
 	}
-	i, err := strconv.ParseInt(s, 10, 32)
+	i, err := strconv.ParseInt(s, 10, 64)
 	if err != nil {
 		return 0, fmt.Errorf("couldn't parse value %s: %s", s, err)
 	}
-	return int(i), nil
+	return i, nil
 }

vendor/github.com/prometheus/procfs/proc_ns.go

@@ -0,0 +1,68 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// Namespace represents a single namespace of a process.
+type Namespace struct {
+	Type  string // Namespace type.
+	Inode uint32 // Inode number of the namespace. If two processes are in the same namespace their inodes will match.
+}
+
+// Namespaces contains all of the namespaces that the process is contained in.
+type Namespaces map[string]Namespace
+
+// Namespaces reads from /proc/<pid>/ns/* to get the namespaces of which the
+// process is a member.
+func (p Proc) Namespaces() (Namespaces, error) {
+	d, err := os.Open(p.path("ns"))
+	if err != nil {
+		return nil, err
+	}
+	defer d.Close()
+
+	names, err := d.Readdirnames(-1)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read contents of ns dir: %v", err)
+	}
+
+	ns := make(Namespaces, len(names))
+	for _, name := range names {
+		target, err := os.Readlink(p.path("ns", name))
+		if err != nil {
+			return nil, err
+		}
+
+		fields := strings.SplitN(target, ":", 2)
+		if len(fields) != 2 {
+			return nil, fmt.Errorf("failed to parse namespace type and inode from '%v'", target)
+		}
+
+		typ := fields[0]
+		inode, err := strconv.ParseUint(strings.Trim(fields[1], "[]"), 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse inode from '%v': %v", fields[1], err)
+		}
+
+		ns[name] = Namespace{typ, uint32(inode)}
+	}
+
+	return ns, nil
+}

vendor/github.com/prometheus/procfs/proc_psi.go

@@ -0,0 +1,101 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+// The PSI / pressure interface is described at
+//   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/accounting/psi.txt
+// Each resource (cpu, io, memory, ...) is exposed as a single file.
+// Each file may contain up to two lines, one for "some" pressure and one for "full" pressure.
+// Each line contains several averages (over n seconds) and a total in µs.
+//
+// Example io pressure file:
+// > some avg10=0.06 avg60=0.21 avg300=0.99 total=8537362
+// > full avg10=0.00 avg60=0.13 avg300=0.96 total=8183134
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"strings"
+)
+
+const lineFormat = "avg10=%f avg60=%f avg300=%f total=%d"
+
+// PSILine is a single line of values as returned by /proc/pressure/*
+// The Avg entries are averages over n seconds, as a percentage
+// The Total line is in microseconds
+type PSILine struct {
+	Avg10  float64
+	Avg60  float64
+	Avg300 float64
+	Total  uint64
+}
+
+// PSIStats represent pressure stall information from /proc/pressure/*
+// Some indicates the share of time in which at least some tasks are stalled
+// Full indicates the share of time in which all non-idle tasks are stalled simultaneously
+type PSIStats struct {
+	Some *PSILine
+	Full *PSILine
+}
+
+// PSIStatsForResource reads pressure stall information for the specified
+// resource from /proc/pressure/<resource>. At time of writing this can be
+// either "cpu", "memory" or "io".
+func (fs FS) PSIStatsForResource(resource string) (PSIStats, error) {
+	file, err := os.Open(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
+	if err != nil {
+		return PSIStats{}, fmt.Errorf("psi_stats: unavailable for %s", resource)
+	}
+
+	defer file.Close()
+	return parsePSIStats(resource, file)
+}
+
+// parsePSIStats parses the specified file for pressure stall information
+func parsePSIStats(resource string, file io.Reader) (PSIStats, error) {
+	psiStats := PSIStats{}
+	stats, err := ioutil.ReadAll(file)
+	if err != nil {
+		return psiStats, fmt.Errorf("psi_stats: unable to read data for %s", resource)
+	}
+
+	for _, l := range strings.Split(string(stats), "\n") {
+		prefix := strings.Split(l, " ")[0]
+		switch prefix {
+		case "some":
+			psi := PSILine{}
+			_, err := fmt.Sscanf(l, fmt.Sprintf("some %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
+			if err != nil {
+				return PSIStats{}, err
+			}
+			psiStats.Some = &psi
+		case "full":
+			psi := PSILine{}
+			_, err := fmt.Sscanf(l, fmt.Sprintf("full %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
+			if err != nil {
+				return PSIStats{}, err
+			}
+			psiStats.Full = &psi
+		default:
+			// If we encounter a line with an unknown prefix, ignore it and move on
+			// Should new measurement types be added in the future we'll simply ignore them instead
+			// of erroring on retrieval
+			continue
+		}
+	}
+
+	return psiStats, nil
+}

vendor/github.com/prometheus/procfs/proc_stat.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -5,6 +18,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+
+	"github.com/prometheus/procfs/internal/fs"
 )
 
 // Originally, this USER_HZ value was dynamically retrieved via a sysconf call
@@ -82,15 +97,22 @@ type ProcStat struct {
 	// in clock ticks.
 	Starttime uint64
 	// Virtual memory size in bytes.
-	VSize int
+	VSize uint
 	// Resident set size in pages.
 	RSS int
 
-	fs FS
+	proc fs.FS
 }
 
 // NewStat returns the current status information of the process.
+//
+// Deprecated: use NewStat() instead
 func (p Proc) NewStat() (ProcStat, error) {
+	return p.Stat()
+}
+
+// Stat returns the current status information of the process.
+func (p Proc) Stat() (ProcStat, error) {
 	f, err := os.Open(p.path("stat"))
 	if err != nil {
 		return ProcStat{}, err
@@ -105,7 +127,7 @@ func (p Proc) NewStat() (ProcStat, error) {
 	var (
 		ignore int
 
-		s = ProcStat{PID: p.PID, fs: p.fs}
+		s = ProcStat{PID: p.PID, proc: p.fs}
 		l = bytes.Index(data, []byte("("))
 		r = bytes.LastIndex(data, []byte(")"))
 	)
@@ -151,7 +173,7 @@ func (p Proc) NewStat() (ProcStat, error) {
 }
 
 // VirtualMemory returns the virtual memory size in bytes.
-func (s ProcStat) VirtualMemory() int {
+func (s ProcStat) VirtualMemory() uint {
 	return s.VSize
 }
 
@@ -162,7 +184,8 @@ func (s ProcStat) ResidentMemory() int {
 
 // StartTime returns the unix timestamp of the process in seconds.
 func (s ProcStat) StartTime() (float64, error) {
-	stat, err := s.fs.NewStat()
+	fs := FS{proc: s.proc}
+	stat, err := fs.Stat()
 	if err != nil {
 		return 0, err
 	}

vendor/github.com/prometheus/procfs/proc_status.go

@@ -0,0 +1,162 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// ProcStat provides status information about the process,
+// read from /proc/[pid]/stat.
+type ProcStatus struct {
+	// The process ID.
+	PID int
+	// The process name.
+	Name string
+
+	// Peak virtual memory size.
+	VmPeak uint64
+	// Virtual memory size.
+	VmSize uint64
+	// Locked memory size.
+	VmLck uint64
+	// Pinned memory size.
+	VmPin uint64
+	// Peak resident set size.
+	VmHWM uint64
+	// Resident set size (sum of RssAnnon RssFile and RssShmem).
+	VmRSS uint64
+	// Size of resident anonymous memory.
+	RssAnon uint64
+	// Size of resident file mappings.
+	RssFile uint64
+	// Size of resident shared memory.
+	RssShmem uint64
+	// Size of data segments.
+	VmData uint64
+	// Size of stack segments.
+	VmStk uint64
+	// Size of text segments.
+	VmExe uint64
+	// Shared library code size.
+	VmLib uint64
+	// Page table entries size.
+	VmPTE uint64
+	// Size of second-level page tables.
+	VmPMD uint64
+	// Swapped-out virtual memory size by anonymous private.
+	VmSwap uint64
+	// Size of hugetlb memory portions
+	HugetlbPages uint64
+
+	// Number of voluntary context switches.
+	VoluntaryCtxtSwitches uint64
+	// Number of involuntary context switches.
+	NonVoluntaryCtxtSwitches uint64
+}
+
+// NewStatus returns the current status information of the process.
+func (p Proc) NewStatus() (ProcStatus, error) {
+	f, err := os.Open(p.path("status"))
+	if err != nil {
+		return ProcStatus{}, err
+	}
+	defer f.Close()
+
+	data, err := ioutil.ReadAll(f)
+	if err != nil {
+		return ProcStatus{}, err
+	}
+
+	s := ProcStatus{PID: p.PID}
+
+	lines := strings.Split(string(data), "\n")
+	for _, line := range lines {
+		if !bytes.Contains([]byte(line), []byte(":")) {
+			continue
+		}
+
+		kv := strings.SplitN(line, ":", 2)
+
+		// removes spaces
+		k := string(strings.TrimSpace(kv[0]))
+		v := string(strings.TrimSpace(kv[1]))
+		// removes "kB"
+		v = string(bytes.Trim([]byte(v), " kB"))
+
+		// value to int when possible
+		// we can skip error check here, 'cause vKBytes is not used when value is a string
+		vKBytes, _ := strconv.ParseUint(v, 10, 64)
+		// convert kB to B
+		vBytes := vKBytes * 1024
+
+		s.fillStatus(k, v, vKBytes, vBytes)
+	}
+
+	return s, nil
+}
+
+func (s *ProcStatus) fillStatus(k string, vString string, vUint uint64, vUintBytes uint64) {
+	switch k {
+	case "Name":
+		s.Name = vString
+	case "VmPeak":
+		s.VmPeak = vUintBytes
+	case "VmSize":
+		s.VmSize = vUintBytes
+	case "VmLck":
+		s.VmLck = vUintBytes
+	case "VmPin":
+		s.VmPin = vUintBytes
+	case "VmHWM":
+		s.VmHWM = vUintBytes
+	case "VmRSS":
+		s.VmRSS = vUintBytes
+	case "RssAnon":
+		s.RssAnon = vUintBytes
+	case "RssFile":
+		s.RssFile = vUintBytes
+	case "RssShmem":
+		s.RssShmem = vUintBytes
+	case "VmData":
+		s.VmData = vUintBytes
+	case "VmStk":
+		s.VmStk = vUintBytes
+	case "VmExe":
+		s.VmExe = vUintBytes
+	case "VmLib":
+		s.VmLib = vUintBytes
+	case "VmPTE":
+		s.VmPTE = vUintBytes
+	case "VmPMD":
+		s.VmPMD = vUintBytes
+	case "VmSwap":
+		s.VmSwap = vUintBytes
+	case "HugetlbPages":
+		s.HugetlbPages = vUintBytes
+	case "voluntary_ctxt_switches":
+		s.VoluntaryCtxtSwitches = vUint
+	case "nonvoluntary_ctxt_switches":
+		s.NonVoluntaryCtxtSwitches = vUint
+	}
+}
+
+// TotalCtxtSwitches returns the total context switch.
+func (s ProcStatus) TotalCtxtSwitches() uint64 {
+	return s.VoluntaryCtxtSwitches + s.NonVoluntaryCtxtSwitches
+}

vendor/github.com/prometheus/procfs/stat.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -7,6 +20,8 @@ import (
 	"os"
 	"strconv"
 	"strings"
+
+	"github.com/prometheus/procfs/internal/fs"
 )
 
 // CPUStat shows how much time the cpu spend in various stages.
@@ -65,16 +80,6 @@ type Stat struct {
 	SoftIRQ SoftIRQStat
 }
 
-// NewStat returns kernel/system statistics read from /proc/stat.
-func NewStat() (Stat, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return Stat{}, err
-	}
-
-	return fs.NewStat()
-}
-
 // Parse a cpu statistics line and returns the CPUStat struct plus the cpu id (or -1 for the overall sum).
 func parseCPUStat(line string) (CPUStat, int64, error) {
 	cpuStat := CPUStat{}
@@ -136,11 +141,31 @@ func parseSoftIRQStat(line string) (SoftIRQStat, uint64, error) {
 	return softIRQStat, total, nil
 }
 
-// NewStat returns an information about current kernel/system statistics.
-func (fs FS) NewStat() (Stat, error) {
-	// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+// NewStat returns information about current cpu/process statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+//
+// Deprecated: use fs.Stat() instead
+func NewStat() (Stat, error) {
+	fs, err := NewFS(fs.DefaultProcMountPoint)
+	if err != nil {
+		return Stat{}, err
+	}
+	return fs.Stat()
+}
 
-	f, err := os.Open(fs.Path("stat"))
+// NewStat returns information about current cpu/process statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+//
+// Deprecated: use fs.Stat() instead
+func (fs FS) NewStat() (Stat, error) {
+	return fs.Stat()
+}
+
+// Stat returns information about current cpu/process statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+func (fs FS) Stat() (Stat, error) {
+
+	f, err := os.Open(fs.proc.Path("stat"))
 	if err != nil {
 		return Stat{}, err
 	}

vendor/github.com/prometheus/procfs/ttar

@@ -1,11 +1,26 @@
 #!/usr/bin/env bash
+
 # Purpose: plain text tar format
 # Limitations: - only suitable for text files, directories, and symlinks
 #              - stores only filename, content, and mode
 #              - not designed for untrusted input
-
+#
 # Note: must work with bash version 3.2 (macOS)
 
+# Copyright 2017 Roger Luethi
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 set -o errexit -o nounset
 
 # Sanitize environment (for instance, standard sorting of glob matches)
@@ -13,6 +28,55 @@ export LC_ALL=C
 
 path=""
 CMD=""
+ARG_STRING="$*"
+
+#------------------------------------------------------------------------------
+# Not all sed implementations can work on null bytes. In order to make ttar
+# work out of the box on macOS, use Python as a stream editor.
+
+USE_PYTHON=0
+
+PYTHON_CREATE_FILTER=$(cat << 'PCF'
+#!/usr/bin/env python
+
+import re
+import sys
+
+for line in sys.stdin:
+    line = re.sub(r'EOF', r'\EOF', line)
+    line = re.sub(r'NULLBYTE', r'\NULLBYTE', line)
+    line = re.sub('\x00', r'NULLBYTE', line)
+    sys.stdout.write(line)
+PCF
+)
+
+PYTHON_EXTRACT_FILTER=$(cat << 'PEF'
+#!/usr/bin/env python
+
+import re
+import sys
+
+for line in sys.stdin:
+    line = re.sub(r'(?<!\\)NULLBYTE', '\x00', line)
+    line = re.sub(r'\\NULLBYTE', 'NULLBYTE', line)
+    line = re.sub(r'([^\\])EOF', r'\1', line)
+    line = re.sub(r'\\EOF', 'EOF', line)
+    sys.stdout.write(line)
+PEF
+)
+
+function test_environment {
+    if [[ "$(echo "a" | sed 's/a/\x0/' | wc -c)" -ne 2 ]]; then
+        echo "WARNING sed unable to handle null bytes, using Python (slow)."
+        if ! which python >/dev/null; then
+            echo "ERROR Python not found. Aborting."
+            exit 2
+        fi
+        USE_PYTHON=1
+    fi
+}
+
+#------------------------------------------------------------------------------
 
 function usage {
     bname=$(basename "$0")
@@ -22,7 +86,10 @@ Usage:   $bname [-C <DIR>] -c -f <ARCHIVE> <FILE...> (create archive)
          $bname [-C <DIR>] -x -f <ARCHIVE>           (extract archive)
 
 Options:
-         -C <DIR>                                    (change directory)
+         -C <DIR>           (change directory)
+         -v                 (verbose)
+         --recursive-unlink (recursively delete existing directory if path
+                             collides with file or directory to extract)
 
 Example: Change to sysfs directory, create ttar file from fixtures directory
          $bname -C sysfs -c -f sysfs/fixtures.ttar fixtures/
@@ -45,7 +112,10 @@ function set_cmd {
     CMD=$1
 }
 
-while getopts :cf:htxvC: opt; do
+unset VERBOSE
+unset RECURSIVE_UNLINK
+
+while getopts :cf:-:htxvC: opt; do
     case $opt in
         c)
             set_cmd "create"
@@ -69,6 +139,18 @@ while getopts :cf:htxvC: opt; do
         C)
             CDIR=$OPTARG
             ;;
+        -)
+            case $OPTARG in
+                recursive-unlink)
+                    RECURSIVE_UNLINK="yes"
+                    ;;
+                *)
+                    echo -e "Error: invalid option -$OPTARG"
+                    echo
+                    usage 1
+                    ;;
+            esac
+            ;;
         *)
             echo >&2 "ERROR: invalid option -$OPTARG"
             echo
@@ -142,14 +224,52 @@ function extract {
     fi
     while IFS= read -r line; do
         line_no=$(( line_no + 1 ))
+        local eof_without_newline
         if [ "$size" -gt 0 ]; then
-            echo "$line" >> "$path"
+            if [[ "$line" =~ [^\\]EOF ]]; then
+                # An EOF not preceded by a backslash indicates that the line
+                # does not end with a newline
+                eof_without_newline=1
+            else
+                eof_without_newline=0
+            fi
+            # Replace NULLBYTE with null byte if at beginning of line
+            # Replace NULLBYTE with null byte unless preceded by backslash
+            # Remove one backslash in front of NULLBYTE (if any)
+            # Remove EOF unless preceded by backslash
+            # Remove one backslash in front of EOF
+            if [ $USE_PYTHON -eq 1 ]; then
+                echo -n "$line" | python -c "$PYTHON_EXTRACT_FILTER" >> "$path"
+            else
+                # The repeated pattern makes up for sed's lack of negative
+                # lookbehind assertions (for consecutive null bytes).
+                echo -n "$line" | \
+                    sed -e 's/^NULLBYTE/\x0/g;
+                            s/\([^\\]\)NULLBYTE/\1\x0/g;
+                            s/\([^\\]\)NULLBYTE/\1\x0/g;
+                            s/\\NULLBYTE/NULLBYTE/g;
+                            s/\([^\\]\)EOF/\1/g;
+                            s/\\EOF/EOF/g;
+                    ' >> "$path"
+            fi
+            if [[ "$eof_without_newline" -eq 0 ]]; then
+                echo >> "$path"
+            fi
             size=$(( size - 1 ))
             continue
         fi
         if [[ $line =~ ^Path:\ (.*)$ ]]; then
             path=${BASH_REMATCH[1]}
-            if [ -e "$path" ] || [ -L "$path" ]; then
+            if [ -L "$path" ]; then
+                rm "$path"
+            elif [ -d "$path" ]; then
+                if [ "${RECURSIVE_UNLINK:-}" == "yes" ]; then
+                    rm -r "$path"
+                else
+                    # Safe because symlinks to directories are dealt with above
+                    rmdir "$path"
+                fi
+            elif [ -e "$path" ]; then
                 rm "$path"
             fi
         elif [[ $line =~ ^Lines:\ (.*)$ ]]; then
@@ -187,11 +307,14 @@ function get_mode {
     local mfile=$1
     if [ -z "${STAT_OPTION:-}" ]; then
         if stat -c '%a' "$mfile" >/dev/null 2>&1; then
+            # GNU stat
             STAT_OPTION='-c'
             STAT_FORMAT='%a'
         else
+            # BSD stat
             STAT_OPTION='-f'
-            STAT_FORMAT='%A'
+            # Octal output, user/group/other (omit file type, sticky bit)
+            STAT_FORMAT='%OLp'
         fi
     fi
     stat "${STAT_OPTION}" "${STAT_FORMAT}" "$mfile"
@@ -200,6 +323,7 @@ function get_mode {
 function _create {
     shopt -s nullglob
     local mode
+    local eof_without_newline
     while (( "$#" )); do
         file=$1
         if [ -L "$file" ]; then
@@ -223,8 +347,30 @@ function _create {
         elif [ -f "$file" ]; then
             echo "Path: $file"
             lines=$(wc -l "$file"|awk '{print $1}')
+            eof_without_newline=0
+            if [[ "$(wc -c "$file"|awk '{print $1}')" -gt 0 ]] && \
+                    [[ "$(tail -c 1 "$file" | wc -l)" -eq 0 ]]; then
+                eof_without_newline=1
+                lines=$((lines+1))
+            fi
             echo "Lines: $lines"
-            cat "$file"
+            # Add backslash in front of EOF
+            # Add backslash in front of NULLBYTE
+            # Replace null byte with NULLBYTE
+            if [ $USE_PYTHON -eq 1 ]; then
+                < "$file" python -c "$PYTHON_CREATE_FILTER"
+            else
+                < "$file" \
+                    sed 's/EOF/\\EOF/g;
+                            s/NULLBYTE/\\NULLBYTE/g;
+                            s/\x0/NULLBYTE/g;
+                    '
+            fi
+            if [[ "$eof_without_newline" -eq 1 ]]; then
+                # Finish line with EOF to indicate that the original line did
+                # not end with a linefeed
+                echo "EOF"
+            fi
             mode=$(get_mode "$file")
             echo "Mode: $mode"
             vecho "$mode $file"
@@ -249,9 +395,12 @@ function create {
         rm "$ttar_file"
     fi
     exec > "$ttar_file"
+    echo "# Archive created by ttar $ARG_STRING"
     _create "$@"
 }
 
+test_environment
+
 if [ -n "${CDIR:-}" ]; then
     if [[ "$ARCHIVE" != /* ]]; then
         # Relative path: preserve the archive's location before changing

vendor/github.com/prometheus/procfs/xfrm.go

@@ -97,7 +97,7 @@ func NewXfrmStat() (XfrmStat, error) {
 
 // NewXfrmStat reads the xfrm_stat statistics from the 'proc' filesystem.
 func (fs FS) NewXfrmStat() (XfrmStat, error) {
-	file, err := os.Open(fs.Path("net/xfrm_stat"))
+	file, err := os.Open(fs.proc.Path("net/xfrm_stat"))
 	if err != nil {
 		return XfrmStat{}, err
 	}
@@ -113,7 +113,7 @@ func (fs FS) NewXfrmStat() (XfrmStat, error) {
 
 		if len(fields) != 2 {
 			return XfrmStat{}, fmt.Errorf(
-				"couldnt parse %s line %s", file.Name(), s.Text())
+				"couldn't parse %s line %s", file.Name(), s.Text())
 		}
 
 		name := fields[0]

vendor/vendor.json

@@ -330,13 +330,15 @@
 		{"path":"github.com/posener/complete/cmd","checksumSHA1":"NB7uVS0/BJDmNu68vPAlbrq4TME=","revision":"9f41f7636a724791a3b8b1d35e84caa1124f0d3c","revisionTime":"2017-08-29T17:11:12Z"},
 		{"path":"github.com/posener/complete/cmd/install","checksumSHA1":"gSX86Xl0w9hvtntdT8h23DZtSag=","revision":"9f41f7636a724791a3b8b1d35e84caa1124f0d3c","revisionTime":"2017-08-29T17:11:12Z"},
 		{"path":"github.com/posener/complete/match","checksumSHA1":"DMo94FwJAm9ZCYCiYdJU2+bh4no=","revision":"9f41f7636a724791a3b8b1d35e84caa1124f0d3c","revisionTime":"2017-08-29T17:11:12Z"},
-		{"path":"github.com/prometheus/client_golang/prometheus","checksumSHA1":"+5YXakGoZBEMrHp6h64TC5GSFfg=","revision":"671c87b04728565380d95c621edc687bfa00664c","revisionTime":"2017-09-07T15:06:25Z"},
-		{"path":"github.com/prometheus/client_golang/prometheus/promhttp","checksumSHA1":"wsAkYlRRUNx+OAuUOIqdjO7dICM=","revision":"671c87b04728565380d95c621edc687bfa00664c","revisionTime":"2017-09-07T15:06:25Z"},
+		{"path":"github.com/prometheus/client_golang/prometheus","checksumSHA1":"5dHjKxShYVWVB1Fb00dAnR6kqVk=","revision":"2641b987480bca71fb39738eb8c8b0d577cb1d76","revisionTime":"2019-06-07T14:56:44Z","version":"v0.9.4","versionExact":"v0.9.4"},
+		{"path":"github.com/prometheus/client_golang/prometheus/internal","checksumSHA1":"UBqhkyjCz47+S19MVTigxJ2VjVQ=","revision":"2641b987480bca71fb39738eb8c8b0d577cb1d76","revisionTime":"2019-06-07T14:56:44Z","version":"v0.9.4","versionExact":"v0.9.4"},
+		{"path":"github.com/prometheus/client_golang/prometheus/promhttp","checksumSHA1":"V51yx4gq61QCD9clxnps792Eq2Y=","revision":"2641b987480bca71fb39738eb8c8b0d577cb1d76","revisionTime":"2019-06-07T14:56:44Z","version":"v0.9.4","versionExact":"v0.9.4"},
 		{"path":"github.com/prometheus/client_model/go","checksumSHA1":"DvwvOlPNAgRntBzt3b3OSRMS2N4=","revision":"6f3806018612930941127f2a7c6c453ba2c527d2","revisionTime":"2017-02-16T18:52:47Z"},
 		{"path":"github.com/prometheus/common/expfmt","checksumSHA1":"xfnn0THnqNwjwimeTClsxahYrIo=","revision":"2f17f4a9d485bf34b4bfaccc273805040e4f86c8","revisionTime":"2017-09-08T16:18:22Z"},
 		{"path":"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg","checksumSHA1":"GWlM3d2vPYyNATtTFgftS10/A9w=","revision":"2f17f4a9d485bf34b4bfaccc273805040e4f86c8","revisionTime":"2017-09-08T16:18:22Z"},
 		{"path":"github.com/prometheus/common/model","checksumSHA1":"3VoqH7TFfzA6Ds0zFzIbKCUvBmw=","revision":"2f17f4a9d485bf34b4bfaccc273805040e4f86c8","revisionTime":"2017-09-08T16:18:22Z"},
-		{"path":"github.com/prometheus/procfs","checksumSHA1":"ihxJIjxtbEYdQKwA0D0nRipj95I=","revision":"e645f4e5aaa8506fc71d6edbc5c4ff02c04c46f2","revisionTime":"2017-07-03T10:12:42Z"},
+		{"path":"github.com/prometheus/procfs","checksumSHA1":"WB7dFqkmD3R514xql9YM3ZP1dDM=","revision":"833678b5bb319f2d20a475cb165c6cc59c2cc77c","revisionTime":"2019-05-31T16:30:47Z","version":"v0.0.2","versionExact":"v0.0.2"},
+		{"path":"github.com/prometheus/procfs/internal/fs","checksumSHA1":"Kmjs49lbjGmlgUPx3pks0tVDed0=","revision":"833678b5bb319f2d20a475cb165c6cc59c2cc77c","revisionTime":"2019-05-31T16:30:47Z","version":"v0.0.2","versionExact":"v0.0.2"},
 		{"path":"github.com/prometheus/procfs/xfs","checksumSHA1":"xCiFAAwVTrjsfZT1BIJQ3DgeNCY=","revision":"e645f4e5aaa8506fc71d6edbc5c4ff02c04c46f2","revisionTime":"2017-07-03T10:12:42Z"},
 		{"path":"github.com/rs/cors","checksumSHA1":"I778b2sbNN/yjwKSdb3y7hz2yUQ=","revision":"eabcc6af4bbe5ad3a949d36450326a2b0b9894b8","revisionTime":"2017-08-01T07:32:01Z"},
 		{"path":"github.com/ryanuber/columnize","checksumSHA1":"M57Rrfc8Z966p+IBtQ91QOcUtcg=","comment":"v2.0.1-8-g983d3a5","revision":"abc90934186a77966e2beeac62ed966aac0561d5","revisionTime":"2017-07-03T20:58:27Z"},