Rename linux collectors for build constraints.

collector/lastlogin_linux.go

@@ -0,0 +1,99 @@
+// +build !nolastlogin
+
+package collector
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os/exec"
+	"strings"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/log"
+)
+
+const lastLoginSubsystem = "last_login"
+
+type lastLoginCollector struct {
+	metric prometheus.Gauge
+}
+
+func init() {
+	Factories["lastlogin"] = NewLastLoginCollector
+}
+
+// Takes a prometheus registry and returns a new Collector exposing
+// load, seconds since last login and a list of tags as specified by config.
+func NewLastLoginCollector() (Collector, error) {
+	return &lastLoginCollector{
+		metric: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Subsystem: lastLoginSubsystem,
+			Name:      "time",
+			Help:      "The time of the last login.",
+		}),
+	}, nil
+}
+
+func (c *lastLoginCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	last, err := getLastLoginTime()
+	if err != nil {
+		return fmt.Errorf("Couldn't get last seen: %s", err)
+	}
+	log.Debugf("Set node_last_login_time: %f", last)
+	c.metric.Set(last)
+	c.metric.Collect(ch)
+	return err
+}
+
+func getLastLoginTime() (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(last.Unix()), nil
+}