node_exporter/collector/meminfo_linux.go

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// Copyright 2015 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 !nomeminfo
package collector
import (
"bufio"
"fmt"
"io"
"os"
"regexp"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/log"
)
const (
memInfoSubsystem = "memory"
)
type meminfoCollector struct {
metrics map[string]prometheus.Gauge
}
func init() {
Factories["meminfo"] = NewMeminfoCollector
}
// Takes a prometheus registry and returns a new Collector exposing
// memory stats.
func NewMeminfoCollector() (Collector, error) {
return &meminfoCollector{
metrics: map[string]prometheus.Gauge{},
}, nil
}
func (c *meminfoCollector) Update(ch chan<- prometheus.Metric) (err error) {
memInfo, err := getMemInfo()
if err != nil {
return fmt.Errorf("couldn't get meminfo: %s", err)
}
log.Debugf("Set node_mem: %#v", memInfo)
for k, v := range memInfo {
if _, ok := c.metrics[k]; !ok {
c.metrics[k] = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: Namespace,
Subsystem: memInfoSubsystem,
Name: k,
Help: fmt.Sprintf("Memory information field %s.", k),
})
}
c.metrics[k].Set(v)
c.metrics[k].Collect(ch)
}
return err
}
func getMemInfo() (map[string]float64, error) {
file, err := os.Open(procFilePath("meminfo"))
if err != nil {
return nil, err
}
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defer file.Close()
return parseMemInfo(file)
}
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func parseMemInfo(r io.Reader) (map[string]float64, error) {
var (
memInfo = map[string]float64{}
scanner = bufio.NewScanner(r)
re = regexp.MustCompile("\\((.*)\\)")
)
for scanner.Scan() {
line := scanner.Text()
parts := strings.Fields(string(line))
fv, err := strconv.ParseFloat(parts[1], 64)
if err != nil {
return nil, fmt.Errorf("invalid value in meminfo: %s", err)
}
switch len(parts) {
case 2: // no unit
case 3: // has unit, we presume kB
fv *= 1024
default:
return nil, fmt.Errorf("invalid line in meminfo: %s", line)
}
key := parts[0][:len(parts[0])-1] // remove trailing : from key
// Active(anon) -> Active_anon
key = re.ReplaceAllString(key, "_${1}")
memInfo[key] = fv
}
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return memInfo, nil
}