mirror of
https://github.com/prometheus/node_exporter.git
synced 2024-12-28 23:19:46 -08:00
124 lines
3.5 KiB
Go
124 lines
3.5 KiB
Go
// Copyright 2015 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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// +build !nocpu
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package collector
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import (
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"errors"
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"os"
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"strconv"
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"unsafe"
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"github.com/prometheus/client_golang/prometheus"
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)
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/*
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#cgo LDFLAGS: -lkvm
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#include <fcntl.h>
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#include <kvm.h>
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#include <stdlib.h>
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#include <sys/param.h>
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#include <sys/pcpu.h>
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#include <sys/resource.h>
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#include <sys/sysctl.h>
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#include <sys/time.h>
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long _clockrate() {
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struct clockinfo clockrate;
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size_t size = sizeof(clockrate);
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int res = sysctlbyname("kern.clockrate", &clockrate, &size, NULL, 0);
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if (res == -1) {
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return -1;
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}
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if (size != sizeof(clockrate)) {
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return -2;
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}
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return clockrate.stathz > 0 ? clockrate.stathz : clockrate.hz;
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}
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*/
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import "C"
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type statCollector struct {
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cpu *prometheus.CounterVec
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}
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func init() {
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Factories["cpu"] = NewStatCollector
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}
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// Takes a prometheus registry and returns a new Collector exposing
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// CPU stats.
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func NewStatCollector() (Collector, error) {
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return &statCollector{
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cpu: prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Namespace: Namespace,
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Name: "cpu_seconds_total",
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Help: "Seconds the CPU spent in each mode.",
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},
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[]string{"cpu", "mode"},
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),
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}, nil
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}
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// Expose CPU stats using KVM.
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func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
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if os.Geteuid() != 0 && os.Getegid() != 2 {
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return errors.New("caller should be either root user or kmem group to access /dev/mem")
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}
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var errbuf *C.char
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kd := C.kvm_open(nil, nil, nil, C.O_RDONLY, errbuf)
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if errbuf != nil {
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return errors.New("failed to call kvm_open()")
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}
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defer C.kvm_close(kd)
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// The cp_time variable is an array of CPUSTATES long integers -- in
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// the same format as the kern.cp_time sysctl. According to the
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// comments in sys/kern/kern_clock.c, the frequency of this timer will
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// be stathz (or hz, if stathz is zero).
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clockrate, err := getClockRate()
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if err != nil {
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return err
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}
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ncpus := C.kvm_getncpus(kd)
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for i := 0; i < int(ncpus); i++ {
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pcpu := C.kvm_getpcpu(kd, C.int(i))
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cp_time := ((*C.struct_pcpu)(unsafe.Pointer(pcpu))).pc_cp_time
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c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "user"}).Set(float64(cp_time[C.CP_USER])/clockrate)
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c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "nice"}).Set(float64(cp_time[C.CP_NICE])/clockrate)
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c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "system"}).Set(float64(cp_time[C.CP_SYS])/clockrate)
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c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "interrupt"}).Set(float64(cp_time[C.CP_INTR])/clockrate)
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c.cpu.With(prometheus.Labels{"cpu": strconv.Itoa(i), "mode": "idle"}).Set(float64(cp_time[C.CP_IDLE])/clockrate)
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}
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c.cpu.Collect(ch)
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return err
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}
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func getClockRate() (float64, error) {
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clockrate := C._clockrate()
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if clockrate == -1 {
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return 0, errors.New("sysctl(kern.clockrate) failed")
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} else if clockrate == -2 {
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return 0, errors.New("sysctl(kern.clockrate) failed, wrong buffer size")
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} else if clockrate <= 0 {
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return 0, errors.New("sysctl(kern.clockrate) bad clocktime")
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}
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return float64(clockrate), nil
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}
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