Collect at every scrape, rather than at regular intervals.

Switch to Update using the Collecter Collect interface, due to not knowing all
metricnames in all modules beforehand we can't use Describe and thus the full
Collecter interface.

Remove 'updates', it's meaning varies by module and doesn't add much.

node_exporter.go

@@ -28,7 +28,6 @@ var (
 	listeningAddress  = flag.String("listen", ":8080", "address to listen on")
 	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")
 
 	collectorLabelNames = []string{"collector", "result"}
 
@@ -41,78 +40,56 @@ var (
 		},
 		collectorLabelNames,
 	)
-	metricsUpdated = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: collector.Namespace,
-			Subsystem: subsystem,
-			Name:      "metrics_updated",
-			Help:      "node_exporter: Number of metrics updated.",
-		},
-		collectorLabelNames,
-	)
 )
 
-func main() {
-	flag.Parse()
-	if *printCollectors {
-		fmt.Printf("Available collectors:\n")
-		for n, _ := range collector.Factories {
-			fmt.Printf(" - %s\n", n)
-		}
-		return
+// Implements Collector.
+type NodeCollector struct {
+	collectors map[string]collector.Collector
+}
+
+// Implements Collector.
+func (n NodeCollector) Describe(ch chan<- *prometheus.Desc) {
+	scrapeDurations.Describe(ch)
+}
+
+// Implements Collector.
+func (n NodeCollector) Collect(ch chan<- prometheus.Metric) {
+	wg := sync.WaitGroup{}
+	wg.Add(len(n.collectors))
+	for name, c := range n.collectors {
+		go func(name string, c collector.Collector) {
+			Execute(name, c, ch)
+			wg.Done()
+		}(name, c)
 	}
-	collectors, err := loadCollectors(*configFile)
+	wg.Wait()
+	scrapeDurations.Collect(ch)
+}
+
+func Execute(name string, c collector.Collector, ch chan<- prometheus.Metric) {
+	begin := time.Now()
+	err := c.Update(ch)
+	duration := time.Since(begin)
+	var result string
+
 	if err != nil {
-		log.Fatalf("Couldn't load config and collectors: %s", err)
+		glog.Infof("ERROR: %s failed after %fs: %s", name, duration.Seconds(), err)
+		result = "error"
+	} else {
+		glog.Infof("OK: %s success after %fs.", name, duration.Seconds())
+		result = "success"
 	}
+	scrapeDurations.WithLabelValues(name, result).Observe(duration.Seconds())
+}
 
-	prometheus.MustRegister(scrapeDurations)
-	prometheus.MustRegister(metricsUpdated)
-
-	glog.Infof("Enabled collectors:")
-	for n, _ := range collectors {
-		glog.Infof(" - %s", n)
+func getConfig(file string) (*collector.Config, error) {
+	config := &collector.Config{}
+	glog.Infof("Reading config %s", *configFile)
+	bytes, err := ioutil.ReadFile(*configFile)
+	if err != nil {
+		return nil, err
 	}
-
-	sigHup := make(chan os.Signal)
-	sigUsr1 := make(chan os.Signal)
-	signal.Notify(sigHup, syscall.SIGHUP)
-	signal.Notify(sigUsr1, syscall.SIGUSR1)
-
-	go serveStatus()
-
-	glog.Infof("Starting initial collection")
-	collect(collectors)
-
-	tick := time.Tick(*interval)
-	for {
-		select {
-		case <-sigHup:
-			collectors, err = loadCollectors(*configFile)
-			if err != nil {
-				log.Fatalf("Couldn't load config and collectors: %s", err)
-			}
-			glog.Infof("Reloaded collectors and config")
-			tick = time.Tick(*interval)
-
-		case <-tick:
-			glog.Infof("Starting new interval")
-			collect(collectors)
-
-		case <-sigUsr1:
-			glog.Infof("got signal")
-			if *memProfile != "" {
-				glog.Infof("Writing memory profile to %s", *memProfile)
-				f, err := os.Create(*memProfile)
-				if err != nil {
-					log.Fatal(err)
-				}
-				pprof.WriteHeapProfile(f)
-				f.Close()
-			}
-		}
-	}
-
+	return config, json.Unmarshal(bytes, &config)
 }
 
 func loadCollectors(file string) (map[string]collector.Collector, error) {
@@ -135,46 +112,50 @@ func loadCollectors(file string) (map[string]collector.Collector, error) {
 	return collectors, nil
 }
 
-func getConfig(file string) (*collector.Config, error) {
-	config := &collector.Config{}
-	glog.Infof("Reading config %s", *configFile)
-	bytes, err := ioutil.ReadFile(*configFile)
+func main() {
+	flag.Parse()
+	if *printCollectors {
+		fmt.Printf("Available collectors:\n")
+		for n, _ := range collector.Factories {
+			fmt.Printf(" - %s\n", n)
+		}
+		return
+	}
+	collectors, err := loadCollectors(*configFile)
 	if err != nil {
-		return nil, err
+		log.Fatalf("Couldn't load config and collectors: %s", err)
 	}
-	return config, json.Unmarshal(bytes, &config)
-}
 
-func serveStatus() {
-	http.Handle("/metrics", prometheus.Handler())
-	http.ListenAndServe(*listeningAddress, nil)
-}
-
-func collect(collectors map[string]collector.Collector) {
-	wg := sync.WaitGroup{}
-	wg.Add(len(collectors))
-	for n, c := range collectors {
-		go func(n string, c collector.Collector) {
-			Execute(n, c)
-			wg.Done()
-		}(n, c)
+	glog.Infof("Enabled collectors:")
+	for n, _ := range collectors {
+		glog.Infof(" - %s", n)
 	}
-	wg.Wait()
-}
 
-func Execute(name string, c collector.Collector) {
-	begin := time.Now()
-	updates, err := c.Update()
-	duration := time.Since(begin)
-	var result string
+	nodeCollector := NodeCollector{collectors: collectors}
+	prometheus.MustRegister(nodeCollector)
 
-	if err != nil {
-		glog.Infof("ERROR: %s failed after %fs: %s", name, duration.Seconds(), err)
-		result = "error"
-	} else {
-		glog.Infof("OK: %s success after %fs.", name, duration.Seconds())
-		result = "success"
+	sigUsr1 := make(chan os.Signal)
+	signal.Notify(sigUsr1, syscall.SIGUSR1)
+
+	go func() {
+		http.Handle("/metrics", prometheus.Handler())
+		http.ListenAndServe(*listeningAddress, nil)
+	}()
+
+	for {
+		select {
+		case <-sigUsr1:
+			glog.Infof("got signal")
+			if *memProfile != "" {
+				glog.Infof("Writing memory profile to %s", *memProfile)
+				f, err := os.Create(*memProfile)
+				if err != nil {
+					log.Fatal(err)
+				}
+				pprof.WriteHeapProfile(f)
+				f.Close()
+			}
+		}
 	}
-	scrapeDurations.WithLabelValues(name, result).Observe(duration.Seconds())
-	metricsUpdated.WithLabelValues(name, result).Set(float64(updates))
+
 }