Node_Exporter/collector/processes_linux.go
Ben Kochie fe5a117831
Handle vanishing PIDs (#1043)
PIDs can vanish (exit) from /proc/ between gathering the list of PIDs
and getting all of their stats.

* Ignore file not found errors.
* Explicitly count the PIDs we find.
* Cleanup some error style issues.

Signed-off-by: Ben Kochie <superq@gmail.com>
2018-08-13 17:27:23 +02:00

120 lines
3.6 KiB
Go

// 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.
// +build !noprocesses
package collector
import (
"fmt"
"os"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
"github.com/prometheus/procfs"
)
type processCollector struct {
threadAlloc *prometheus.Desc
threadLimit *prometheus.Desc
procsState *prometheus.Desc
pidUsed *prometheus.Desc
pidMax *prometheus.Desc
}
func init() {
registerCollector("processes", defaultDisabled, NewProcessStatCollector)
}
func NewProcessStatCollector() (Collector, error) {
subsystem := "processes"
return &processCollector{
threadAlloc: prometheus.NewDesc(
prometheus.BuildFQName(namespace, subsystem, "threads"),
"Allocated threads in system",
nil, nil,
),
threadLimit: prometheus.NewDesc(
prometheus.BuildFQName(namespace, subsystem, "max_threads"),
"Limit of threads in the system",
nil, nil,
),
procsState: prometheus.NewDesc(
prometheus.BuildFQName(namespace, subsystem, "state"),
"Number of processes in each state.",
[]string{"state"}, nil,
),
pidUsed: prometheus.NewDesc(prometheus.BuildFQName(namespace, subsystem, "pids"),
"Number of PIDs", nil, nil,
),
pidMax: prometheus.NewDesc(prometheus.BuildFQName(namespace, subsystem, "max_processes"),
"Number of max PIDs limit", nil, nil,
),
}, nil
}
func (t *processCollector) Update(ch chan<- prometheus.Metric) error {
pids, states, threads, err := getAllocatedThreads()
if err != nil {
return fmt.Errorf("unable to retrieve number of allocated threads: %q", err)
}
ch <- prometheus.MustNewConstMetric(t.threadAlloc, prometheus.GaugeValue, float64(threads))
maxThreads, err := readUintFromFile(procFilePath("sys/kernel/threads-max"))
if err != nil {
return fmt.Errorf("unable to retrieve limit number of threads: %q", err)
}
ch <- prometheus.MustNewConstMetric(t.threadLimit, prometheus.GaugeValue, float64(maxThreads))
for state := range states {
ch <- prometheus.MustNewConstMetric(t.procsState, prometheus.GaugeValue, float64(states[state]), state)
}
pidM, err := readUintFromFile(procFilePath("sys/kernel/pid_max"))
if err != nil {
return fmt.Errorf("unable to retrieve limit number of maximum pids alloved: %q", err)
}
ch <- prometheus.MustNewConstMetric(t.pidUsed, prometheus.GaugeValue, float64(pids))
ch <- prometheus.MustNewConstMetric(t.pidMax, prometheus.GaugeValue, float64(pidM))
return nil
}
func getAllocatedThreads() (int, map[string]int32, int, error) {
fs, err := procfs.NewFS(*procPath)
if err != nil {
return 0, nil, 0, err
}
p, err := fs.AllProcs()
if err != nil {
return 0, nil, 0, err
}
pids := 0
thread := 0
procStates := make(map[string]int32)
for _, pid := range p {
stat, err := pid.NewStat()
// PIDs can vanish between getting the list and getting stats.
if os.IsNotExist(err) {
log.Debugf("file not found when retrieving stats: %q", err)
continue
}
if err != nil {
return 0, nil, 0, err
}
pids += 1
procStates[stat.State] += 1
thread += stat.NumThreads
}
return pids, procStates, thread, nil
}