421 lines
12 KiB
Go
421 lines
12 KiB
Go
// +build go1.9
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package prometheus
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import (
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"fmt"
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"log"
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"math"
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"regexp"
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"strings"
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"sync"
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"time"
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"github.com/armon/go-metrics"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/push"
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)
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var (
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// DefaultPrometheusOpts is the default set of options used when creating a
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// PrometheusSink.
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DefaultPrometheusOpts = PrometheusOpts{
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Expiration: 60 * time.Second,
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}
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)
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// PrometheusOpts is used to configure the Prometheus Sink
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type PrometheusOpts struct {
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// Expiration is the duration a metric is valid for, after which it will be
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// untracked. If the value is zero, a metric is never expired.
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Expiration time.Duration
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Registerer prometheus.Registerer
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// Gauges, Summaries, and Counters allow us to pre-declare metrics by giving their Name, Help, and ConstLabels to
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// the PrometheusSink when it is created. Metrics declared in this way will be initialized at zero and will not be
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// deleted when their expiry is reached.
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// - Gauges and Summaries will be set to NaN when they expire.
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// - Counters continue to Collect their last known value.
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// Ex:
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// PrometheusOpts{
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// Expiration: 10 * time.Second,
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// Gauges: []GaugeDefinition{
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// {
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// Name: []string{ "application", "component", "measurement"},
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// Help: "application_component_measurement provides an example of how to declare static metrics",
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// ConstLabels: []metrics.Label{ { Name: "my_label", Value: "does_not_change" }, },
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// },
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// },
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// }
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GaugeDefinitions []GaugeDefinition
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SummaryDefinitions []SummaryDefinition
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CounterDefinitions []CounterDefinition
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}
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type PrometheusSink struct {
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// If these will ever be copied, they should be converted to *sync.Map values and initialized appropriately
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gauges sync.Map
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summaries sync.Map
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counters sync.Map
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expiration time.Duration
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}
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// GaugeDefinition can be provided to PrometheusOpts to declare a constant gauge that is not deleted on expiry.
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type GaugeDefinition struct {
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Name []string
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ConstLabels []metrics.Label
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Help string
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}
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type gauge struct {
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prometheus.Gauge
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updatedAt time.Time
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// canDelete is set if the metric is created during runtime so we know it's ephemeral and can delete it on expiry.
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canDelete bool
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}
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// SummaryDefinition can be provided to PrometheusOpts to declare a constant summary that is not deleted on expiry.
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type SummaryDefinition struct {
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Name []string
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ConstLabels []metrics.Label
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Help string
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}
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type summary struct {
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prometheus.Summary
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updatedAt time.Time
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canDelete bool
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}
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// CounterDefinition can be provided to PrometheusOpts to declare a constant counter that is not deleted on expiry.
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type CounterDefinition struct {
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Name []string
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ConstLabels []metrics.Label
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Help string
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}
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type counter struct {
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prometheus.Counter
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updatedAt time.Time
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canDelete bool
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}
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// NewPrometheusSink creates a new PrometheusSink using the default options.
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func NewPrometheusSink() (*PrometheusSink, error) {
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return NewPrometheusSinkFrom(DefaultPrometheusOpts)
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}
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// NewPrometheusSinkFrom creates a new PrometheusSink using the passed options.
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func NewPrometheusSinkFrom(opts PrometheusOpts) (*PrometheusSink, error) {
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sink := &PrometheusSink{
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gauges: sync.Map{},
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summaries: sync.Map{},
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counters: sync.Map{},
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expiration: opts.Expiration,
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}
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initGauges(&sink.gauges, opts.GaugeDefinitions)
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initSummaries(&sink.summaries, opts.SummaryDefinitions)
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initCounters(&sink.counters, opts.CounterDefinitions)
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reg := opts.Registerer
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if reg == nil {
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reg = prometheus.DefaultRegisterer
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}
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return sink, reg.Register(sink)
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}
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// Describe is needed to meet the Collector interface.
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func (p *PrometheusSink) Describe(c chan<- *prometheus.Desc) {
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// We must emit some description otherwise an error is returned. This
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// description isn't shown to the user!
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prometheus.NewGauge(prometheus.GaugeOpts{Name: "Dummy", Help: "Dummy"}).Describe(c)
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}
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// Collect meets the collection interface and allows us to enforce our expiration
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// logic to clean up ephemeral metrics if their value haven't been set for a
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// duration exceeding our allowed expiration time.
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func (p *PrometheusSink) Collect(c chan<- prometheus.Metric) {
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expire := p.expiration != 0
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now := time.Now()
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p.gauges.Range(func(k, v interface{}) bool {
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if v == nil {
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return true
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}
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g := v.(*gauge)
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lastUpdate := g.updatedAt
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if expire && lastUpdate.Add(p.expiration).Before(now) {
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if g.canDelete {
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p.gauges.Delete(k)
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return true
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}
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// We have not observed the gauge this interval so we don't know its value.
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g.Set(math.NaN())
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}
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g.Collect(c)
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return true
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})
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p.summaries.Range(func(k, v interface{}) bool {
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if v == nil {
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return true
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}
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s := v.(*summary)
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lastUpdate := s.updatedAt
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if expire && lastUpdate.Add(p.expiration).Before(now) {
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if s.canDelete {
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p.summaries.Delete(k)
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return true
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}
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// We have observed nothing in this interval.
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s.Observe(math.NaN())
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}
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s.Collect(c)
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return true
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})
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p.counters.Range(func(k, v interface{}) bool {
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if v == nil {
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return true
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}
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count := v.(*counter)
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lastUpdate := count.updatedAt
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if expire && lastUpdate.Add(p.expiration).Before(now) {
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if count.canDelete {
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p.counters.Delete(k)
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return true
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}
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// Counters remain at their previous value when not observed, so we do not set it to NaN.
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}
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count.Collect(c)
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return true
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})
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}
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func initGauges(m *sync.Map, gauges []GaugeDefinition) {
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for _, g := range gauges {
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key, hash := flattenKey(g.Name, g.ConstLabels)
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pG := prometheus.NewGauge(prometheus.GaugeOpts{
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Name: key,
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Help: g.Help,
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ConstLabels: prometheusLabels(g.ConstLabels),
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})
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m.Store(hash, &gauge{ Gauge: pG })
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}
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return
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}
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func initSummaries(m *sync.Map, summaries []SummaryDefinition) {
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for _, s := range summaries {
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key, hash := flattenKey(s.Name, s.ConstLabels)
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pS := prometheus.NewSummary(prometheus.SummaryOpts{
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Name: key,
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Help: s.Help,
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MaxAge: 10 * time.Second,
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ConstLabels: prometheusLabels(s.ConstLabels),
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Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
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})
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m.Store(hash, &summary{ Summary: pS })
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}
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return
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}
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func initCounters(m *sync.Map, counters []CounterDefinition) {
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for _, c := range counters {
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key, hash := flattenKey(c.Name, c.ConstLabels)
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pC := prometheus.NewCounter(prometheus.CounterOpts{
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Name: key,
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Help: c.Help,
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ConstLabels: prometheusLabels(c.ConstLabels),
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})
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m.Store(hash, &counter{ Counter: pC })
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}
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return
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}
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var forbiddenChars = regexp.MustCompile("[ .=\\-/]")
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func flattenKey(parts []string, labels []metrics.Label) (string, string) {
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key := strings.Join(parts, "_")
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key = forbiddenChars.ReplaceAllString(key, "_")
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hash := key
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for _, label := range labels {
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hash += fmt.Sprintf(";%s=%s", label.Name, label.Value)
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}
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return key, hash
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}
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func prometheusLabels(labels []metrics.Label) prometheus.Labels {
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l := make(prometheus.Labels)
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for _, label := range labels {
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l[label.Name] = label.Value
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}
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return l
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}
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func (p *PrometheusSink) SetGauge(parts []string, val float32) {
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p.SetGaugeWithLabels(parts, val, nil)
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}
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func (p *PrometheusSink) SetGaugeWithLabels(parts []string, val float32, labels []metrics.Label) {
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key, hash := flattenKey(parts, labels)
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pg, ok := p.gauges.Load(hash)
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// The sync.Map underlying gauges stores pointers to our structs. If we need to make updates,
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// rather than modifying the underlying value directly, which would be racy, we make a local
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// copy by dereferencing the pointer we get back, making the appropriate changes, and then
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// storing a pointer to our local copy. The underlying Prometheus types are threadsafe,
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// so there's no issues there. It's possible for racy updates to occur to the updatedAt
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// value, but since we're always setting it to time.Now(), it doesn't really matter.
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if ok {
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localGauge := *pg.(*gauge)
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localGauge.Set(float64(val))
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localGauge.updatedAt = time.Now()
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p.gauges.Store(hash, &localGauge)
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// The gauge does not exist, create the gauge and allow it to be deleted
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} else {
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g := prometheus.NewGauge(prometheus.GaugeOpts{
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Name: key,
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Help: key,
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ConstLabels: prometheusLabels(labels),
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})
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g.Set(float64(val))
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pg = &gauge{
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Gauge: g,
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updatedAt: time.Now(),
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canDelete: true,
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}
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p.gauges.Store(hash, pg)
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}
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}
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func (p *PrometheusSink) AddSample(parts []string, val float32) {
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p.AddSampleWithLabels(parts, val, nil)
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}
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func (p *PrometheusSink) AddSampleWithLabels(parts []string, val float32, labels []metrics.Label) {
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key, hash := flattenKey(parts, labels)
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ps, ok := p.summaries.Load(hash)
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// Does the summary already exist for this sample type?
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if ok {
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localSummary := *ps.(*summary)
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localSummary.Observe(float64(val))
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localSummary.updatedAt = time.Now()
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p.summaries.Store(hash, &localSummary)
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// The summary does not exist, create the Summary and allow it to be deleted
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} else {
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s := prometheus.NewSummary(prometheus.SummaryOpts{
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Name: key,
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Help: key,
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MaxAge: 10 * time.Second,
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ConstLabels: prometheusLabels(labels),
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Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
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})
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s.Observe(float64(val))
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ps = &summary{
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Summary: s,
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updatedAt: time.Now(),
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canDelete: true,
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}
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p.summaries.Store(hash, ps)
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}
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}
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// EmitKey is not implemented. Prometheus doesn’t offer a type for which an
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// arbitrary number of values is retained, as Prometheus works with a pull
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// model, rather than a push model.
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func (p *PrometheusSink) EmitKey(key []string, val float32) {
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}
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func (p *PrometheusSink) IncrCounter(parts []string, val float32) {
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p.IncrCounterWithLabels(parts, val, nil)
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}
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func (p *PrometheusSink) IncrCounterWithLabels(parts []string, val float32, labels []metrics.Label) {
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key, hash := flattenKey(parts, labels)
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pc, ok := p.counters.Load(hash)
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// Does the counter exist?
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if ok {
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localCounter := *pc.(*counter)
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localCounter.Add(float64(val))
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localCounter.updatedAt = time.Now()
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p.counters.Store(hash, &localCounter)
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// The counter does not exist yet, create it and allow it to be deleted
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} else {
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c := prometheus.NewCounter(prometheus.CounterOpts{
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Name: key,
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Help: key,
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ConstLabels: prometheusLabels(labels),
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})
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c.Add(float64(val))
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pc = &counter{
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Counter: c,
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updatedAt: time.Now(),
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canDelete: true,
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}
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p.counters.Store(hash, pc)
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}
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}
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// PrometheusPushSink wraps a normal prometheus sink and provides an address and facilities to export it to an address
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// on an interval.
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type PrometheusPushSink struct {
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*PrometheusSink
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pusher *push.Pusher
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address string
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pushInterval time.Duration
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stopChan chan struct{}
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}
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// NewPrometheusPushSink creates a PrometheusPushSink by taking an address, interval, and destination name.
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func NewPrometheusPushSink(address string, pushInterval time.Duration, name string) (*PrometheusPushSink, error) {
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promSink := &PrometheusSink{
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gauges: sync.Map{},
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summaries: sync.Map{},
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counters: sync.Map{},
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expiration: 60 * time.Second,
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}
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pusher := push.New(address, name).Collector(promSink)
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sink := &PrometheusPushSink{
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promSink,
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pusher,
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address,
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pushInterval,
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make(chan struct{}),
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}
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sink.flushMetrics()
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return sink, nil
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}
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func (s *PrometheusPushSink) flushMetrics() {
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ticker := time.NewTicker(s.pushInterval)
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go func() {
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for {
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select {
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case <-ticker.C:
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err := s.pusher.Push()
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if err != nil {
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log.Printf("[ERR] Error pushing to Prometheus! Err: %s", err)
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}
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case <-s.stopChan:
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ticker.Stop()
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return
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}
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}
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}()
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}
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func (s *PrometheusPushSink) Shutdown() {
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close(s.stopChan)
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}
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