node_exporter/collector/meminfo.go

102 lines
2.1 KiB
Go

// +build !nomeminfo
package collector
import (
"bufio"
"fmt"
"io"
"os"
"regexp"
"strconv"
"strings"
"github.com/golang/glog"
"github.com/prometheus/client_golang/prometheus"
)
const (
procMemInfo = "/proc/meminfo"
)
var (
memInfoMetrics = map[string]prometheus.Gauge{}
)
type meminfoCollector struct {
registry prometheus.Registry
config Config
}
func init() {
Factories["meminfo"] = NewMeminfoCollector
}
// Takes a config struct and prometheus registry and returns a new Collector exposing
// memory stats.
func NewMeminfoCollector(config Config, registry prometheus.Registry) (Collector, error) {
c := meminfoCollector{
config: config,
registry: registry,
}
return &c, nil
}
func (c *meminfoCollector) Update() (updates int, err error) {
memInfo, err := getMemInfo()
if err != nil {
return updates, fmt.Errorf("Couldn't get meminfo: %s", err)
}
glog.V(1).Infof("Set node_mem: %#v", memInfo)
for k, v := range memInfo {
if _, ok := memInfoMetrics[k]; !ok {
memInfoMetrics[k] = prometheus.NewGauge()
c.registry.Register(
"node_memory_"+k,
k+" from /proc/meminfo",
prometheus.NilLabels,
memInfoMetrics[k],
)
}
updates++
memInfoMetrics[k].Set(nil, v)
}
return updates, err
}
func getMemInfo() (map[string]float64, error) {
file, err := os.Open(procMemInfo)
if err != nil {
return nil, err
}
return parseMemInfo(file)
}
func parseMemInfo(r io.ReadCloser) (map[string]float64, error) {
defer r.Close()
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 %s: %s", procMemInfo, line)
}
key := parts[0][:len(parts[0])-1] // remove trailing : from key
// Active(anon) -> Active_anon
key = re.ReplaceAllString(key, "_${1}")
memInfo[key] = fv
}
return memInfo, nil
}