435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
101 lines
3.3 KiB
Go
101 lines
3.3 KiB
Go
// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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// The PSI / pressure interface is described at
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// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/accounting/psi.txt
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// Each resource (cpu, io, memory, ...) is exposed as a single file.
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// Each file may contain up to two lines, one for "some" pressure and one for "full" pressure.
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// Each line contains several averages (over n seconds) and a total in µs.
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//
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// Example io pressure file:
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// > some avg10=0.06 avg60=0.21 avg300=0.99 total=8537362
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// > full avg10=0.00 avg60=0.13 avg300=0.96 total=8183134
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"strings"
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"github.com/prometheus/procfs/internal/util"
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)
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const lineFormat = "avg10=%f avg60=%f avg300=%f total=%d"
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// PSILine is a single line of values as returned by /proc/pressure/*
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// The Avg entries are averages over n seconds, as a percentage
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// The Total line is in microseconds
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type PSILine struct {
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Avg10 float64
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Avg60 float64
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Avg300 float64
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Total uint64
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}
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// PSIStats represent pressure stall information from /proc/pressure/*
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// Some indicates the share of time in which at least some tasks are stalled
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// Full indicates the share of time in which all non-idle tasks are stalled simultaneously
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type PSIStats struct {
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Some *PSILine
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Full *PSILine
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}
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// PSIStatsForResource reads pressure stall information for the specified
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// resource from /proc/pressure/<resource>. At time of writing this can be
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// either "cpu", "memory" or "io".
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func (fs FS) PSIStatsForResource(resource string) (PSIStats, error) {
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data, err := util.ReadFileNoStat(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
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if err != nil {
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return PSIStats{}, fmt.Errorf("psi_stats: unavailable for %s", resource)
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}
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return parsePSIStats(resource, bytes.NewReader(data))
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}
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// parsePSIStats parses the specified file for pressure stall information
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func parsePSIStats(resource string, r io.Reader) (PSIStats, error) {
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psiStats := PSIStats{}
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scanner := bufio.NewScanner(r)
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for scanner.Scan() {
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l := scanner.Text()
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prefix := strings.Split(l, " ")[0]
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switch prefix {
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case "some":
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psi := PSILine{}
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_, err := fmt.Sscanf(l, fmt.Sprintf("some %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
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if err != nil {
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return PSIStats{}, err
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}
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psiStats.Some = &psi
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case "full":
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psi := PSILine{}
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_, err := fmt.Sscanf(l, fmt.Sprintf("full %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
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if err != nil {
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return PSIStats{}, err
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}
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psiStats.Full = &psi
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default:
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// If we encounter a line with an unknown prefix, ignore it and move on
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// Should new measurement types be added in the future we'll simply ignore them instead
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// of erroring on retrieval
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continue
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}
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}
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return psiStats, nil
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}
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