node_exporter/exporter/native_collector.go

155 lines
3.3 KiB
Go

// +build !nonative
package exporter
import (
"bufio"
"fmt"
"github.com/prometheus/client_golang/prometheus"
"io"
"io/ioutil"
"os/exec"
"strconv"
"strings"
"time"
)
const (
procLoad = "/proc/loadavg"
)
type nativeCollector struct {
loadAvg prometheus.Gauge
attributes prometheus.Gauge
lastSeen prometheus.Gauge
name string
config config
}
func init() {
collectorFactories = append(collectorFactories, NewNativeCollector)
}
// Takes a config struct and prometheus registry and returns a new Collector exposing
// load, seconds since last login and a list of tags as specified by config.
func NewNativeCollector(config config, registry prometheus.Registry) (Collector, error) {
c := nativeCollector{
name: "native_collector",
config: config,
loadAvg: prometheus.NewGauge(),
attributes: prometheus.NewGauge(),
lastSeen: prometheus.NewGauge(),
}
registry.Register(
"node_load",
"node_exporter: system load.",
prometheus.NilLabels,
c.loadAvg,
)
registry.Register(
"node_last_login_seconds",
"node_exporter: seconds since last login.",
prometheus.NilLabels,
c.lastSeen,
)
registry.Register(
"node_attributes",
"node_exporter: system attributes.",
prometheus.NilLabels,
c.attributes,
)
return &c, nil
}
func (c *nativeCollector) Name() string { return c.name }
func (c *nativeCollector) Update() (updates int, err error) {
last, err := getSecondsSinceLastLogin()
if err != nil {
return updates, fmt.Errorf("Couldn't get last seen: %s", err)
} else {
updates++
debug(c.Name(), "Set node_last_login_seconds: %f", last)
c.lastSeen.Set(nil, last)
}
load, err := getLoad()
if err != nil {
return updates, fmt.Errorf("Couldn't get load: %s", err)
} else {
updates++
debug(c.Name(), "Set node_load: %f", load)
c.loadAvg.Set(nil, load)
}
debug(c.Name(), "Set node_attributes{%v}: 1", c.config.Attributes)
c.attributes.Set(c.config.Attributes, 1)
return updates, err
}
func getLoad() (float64, error) {
data, err := ioutil.ReadFile(procLoad)
if err != nil {
return 0, err
}
parts := strings.Fields(string(data))
load, err := strconv.ParseFloat(parts[0], 64)
if err != nil {
return 0, fmt.Errorf("Could not parse load '%s': %s", parts[0], err)
}
return load, nil
}
func getSecondsSinceLastLogin() (float64, error) {
who := exec.Command("who", "/var/log/wtmp", "-l", "-u", "-s")
output, err := who.StdoutPipe()
if err != nil {
return 0, err
}
err = who.Start()
if err != nil {
return 0, err
}
reader := bufio.NewReader(output)
var last time.Time
for {
line, isPrefix, err := reader.ReadLine()
if err == io.EOF {
break
}
if isPrefix {
return 0, fmt.Errorf("line to long: %s(...)", line)
}
fields := strings.Fields(string(line))
lastDate := fields[2]
lastTime := fields[3]
dateParts, err := splitToInts(lastDate, "-") // 2013-04-16
if err != nil {
return 0, fmt.Errorf("Couldn't parse date in line '%s': %s", fields, err)
}
timeParts, err := splitToInts(lastTime, ":") // 11:33
if err != nil {
return 0, fmt.Errorf("Couldn't parse time in line '%s': %s", fields, err)
}
last_t := time.Date(dateParts[0], time.Month(dateParts[1]), dateParts[2], timeParts[0], timeParts[1], 0, 0, time.UTC)
last = last_t
}
err = who.Wait()
if err != nil {
return 0, err
}
return float64(time.Now().Sub(last).Seconds()), nil
}