From 32724a10b099c850b308bb8ba484782a591ef407 Mon Sep 17 00:00:00 2001
From: Johannes 'fish' Ziemke <github@freigeist.org>
Date: Mon, 28 Jul 2014 12:36:28 +0200
Subject: [PATCH 1/2] Add NTP exporter

This exporter gets the time from a NTP server and exposes the offset
between the remote and local system time.
---
 collector/ntp.go | 56 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 collector/ntp.go

diff --git a/collector/ntp.go b/collector/ntp.go
new file mode 100644
index 00000000..3e3ca041
--- /dev/null
+++ b/collector/ntp.go
@@ -0,0 +1,56 @@
+// +build !nontp
+
+package collector
+
+import (
+	"flag"
+	"fmt"
+	"time"
+
+	"github.com/beevik/ntp"
+	"github.com/golang/glog"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	ntpServer = flag.String("ntpServer", "", "NTP server to use for ntp collector.")
+	ntpDrift  = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: Namespace,
+		Name:      "ntp_drift_seconds",
+		Help:      "Time between system time and ntp time.",
+	})
+)
+
+type ntpCollector struct {
+}
+
+func init() {
+	Factories["ntp"] = NewNtpCollector
+}
+
+// Takes a config struct and prometheus registry and returns a new Collector exposing
+// the offset between ntp and the current system time.
+func NewNtpCollector(config Config) (Collector, error) {
+	if *ntpServer == "" {
+		return nil, fmt.Errorf("No NTP server specifies, see --ntpServer")
+	}
+	c := ntpCollector{}
+
+	if _, err := prometheus.RegisterOrGet(ntpDrift); err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+func (c *ntpCollector) Update() (updates int, err error) {
+	t, err := ntp.Time(*ntpServer)
+	if err != nil {
+		return updates, fmt.Errorf("Couldn't get ntp drift: %s", err)
+	}
+	drift := t.Sub(time.Now())
+	updates++
+	glog.V(1).Infof("Set ntp_drift_seconds: %f", drift.Seconds())
+	ntpDrift.Set(drift.Seconds())
+
+	return updates, err
+}

From 2b3a112b54d27d7b1ac7dc8f503180bbaf038c77 Mon Sep 17 00:00:00 2001
From: Johannes 'fish' Ziemke <github@freigeist.org>
Date: Mon, 28 Jul 2014 12:37:01 +0200
Subject: [PATCH 2/2] Add time exporter

This simple exporter exposes the systems unix time. It's useful to
compare it to the prometheus server time and other targets to detect
clock skew.
---
 collector/time.go | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 node_exporter.go  |  2 +-
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 collector/time.go

diff --git a/collector/time.go b/collector/time.go
new file mode 100644
index 00000000..172de88f
--- /dev/null
+++ b/collector/time.go
@@ -0,0 +1,47 @@
+// +build !notime
+
+package collector
+
+import (
+	"time"
+
+	"github.com/golang/glog"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	systemTime = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: Namespace,
+		Name:      "time",
+		Help:      "System time in seconds since epoch (1970).",
+	})
+)
+
+type timeCollector struct {
+	config Config
+}
+
+func init() {
+	Factories["time"] = NewTimeCollector
+}
+
+// Takes a config struct and prometheus registry and returns a new Collector exposing
+// the current system time in seconds since epoch.
+func NewTimeCollector(config Config) (Collector, error) {
+	c := timeCollector{
+		config: config,
+	}
+
+	if _, err := prometheus.RegisterOrGet(systemTime); err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+func (c *timeCollector) Update() (updates int, err error) {
+	updates++
+	now := time.Now()
+	glog.V(1).Infof("Set time: %f", now.Unix())
+	systemTime.Set(float64(now.Unix()))
+	return updates, err
+}
diff --git a/node_exporter.go b/node_exporter.go
index 7622cc61..0d8e7b99 100644
--- a/node_exporter.go
+++ b/node_exporter.go
@@ -26,7 +26,7 @@ var (
 	configFile        = flag.String("config", "node_exporter.conf", "config file.")
 	memProfile        = flag.String("memprofile", "", "write memory profile to this file")
 	listeningAddress  = flag.String("listen", ":8080", "address to listen on")
-	enabledCollectors = flag.String("enabledCollectors", "attributes,diskstats,filesystem,loadavg,meminfo,stat,netdev", "comma-seperated list of collectors to use")
+	enabledCollectors = flag.String("enabledCollectors", "attributes,diskstats,filesystem,loadavg,meminfo,stat,time,netdev", "comma-seperated list of collectors to use")
 	printCollectors   = flag.Bool("printCollectors", false, "If true, print available collectors and exit")
 	interval          = flag.Duration("interval", 60*time.Second, "refresh interval")