80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
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package metrics
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import (
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"bytes"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"time"
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)
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const statFilepath = "/proc/self/stat"
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// See https://github.com/prometheus/procfs/blob/a4ac0826abceb44c40fc71daed2b301db498b93e/proc_stat.go#L40 .
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const userHZ = 100
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// See http://man7.org/linux/man-pages/man5/proc.5.html
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type procStat struct {
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State byte
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Ppid int
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Pgrp int
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Session int
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TtyNr int
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Tpgid int
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Flags uint
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Minflt uint
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Cminflt uint
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Majflt uint
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Cmajflt uint
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Utime uint
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Stime uint
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Cutime int
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Cstime int
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Priority int
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Nice int
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NumThreads int
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ItrealValue int
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Starttime uint64
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Vsize uint
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Rss int
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}
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func writeProcessMetrics(w io.Writer) {
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data, err := ioutil.ReadFile(statFilepath)
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if err != nil {
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log.Printf("ERROR: cannot open %s: %s", statFilepath, err)
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return
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}
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// Search for the end of command.
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n := bytes.LastIndex(data, []byte(") "))
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if n < 0 {
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log.Printf("ERROR: cannot find command in parentheses in %q read from %s", data, statFilepath)
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return
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}
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data = data[n+2:]
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var p procStat
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bb := bytes.NewBuffer(data)
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_, err = fmt.Fscanf(bb, "%c %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d",
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&p.State, &p.Ppid, &p.Pgrp, &p.Session, &p.TtyNr, &p.Tpgid, &p.Flags, &p.Minflt, &p.Cminflt, &p.Majflt, &p.Cmajflt,
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&p.Utime, &p.Stime, &p.Cutime, &p.Cstime, &p.Priority, &p.Nice, &p.NumThreads, &p.ItrealValue, &p.Starttime, &p.Vsize, &p.Rss)
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if err != nil {
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log.Printf("ERROR: cannot parse %q read from %s: %s", data, statFilepath, err)
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return
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}
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// It is expensive obtaining `process_open_fds` when big number of file descriptors is opened,
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// don't do it here.
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fmt.Fprintf(w, "process_cpu_seconds_total %g\n", float64(p.Utime+p.Stime)/userHZ)
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fmt.Fprintf(w, "process_major_pagefaults_total %d\n", p.Majflt)
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fmt.Fprintf(w, "process_minor_pagefaults_total %d\n", p.Minflt)
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fmt.Fprintf(w, "process_num_threads %d\n", p.NumThreads)
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fmt.Fprintf(w, "process_resident_memory_bytes %d\n", p.Rss*4096)
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fmt.Fprintf(w, "process_start_time_seconds %d\n", startTimeSeconds)
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fmt.Fprintf(w, "process_virtual_memory_bytes %d\n", p.Vsize)
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}
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var startTimeSeconds = time.Now().Unix()
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