statsdaemon: add health monitoring

README.md

@@ -58,4 +58,5 @@ Usage of ./statsdaemon:
   -receive-counter="": Metric name for total metrics received per interval
   -tcpaddr="": TCP service address, if set
   -version=false: print version string
+  -heartbeat-file="": heartbeat file to update after a successful write to graphite
 ```

statsdaemon.go

@@ -101,6 +101,7 @@ var (
 	percentThreshold  = Percentiles{}
 	prefix            = flag.String("prefix", "", "Prefix for all stats")
 	postfix           = flag.String("postfix", "", "Postfix for all stats")
+	heartbeatFilePath = flag.String("heartbeat-file", "", "heartbeat file to update after a successful write to graphite.")
 )
 
 func init() {
@@ -245,6 +246,9 @@ func submit(deadline time.Time) error {
 	}
 
 	log.Printf("sent %d stats to %s", num, *graphiteAddress)
+	if *heartbeatFilePath != "" {
+		heartbeat()
+	}
 
 	return nil
 }
@@ -572,6 +576,26 @@ func tcpListener() {
 	}
 }
 
+func heartbeat() {
+	_, err := os.Stat(*heartbeatFilePath)
+	if os.IsNotExist(err) {
+		file, err := os.Create(*heartbeatFilePath)
+		if err != nil {
+			log.Fatalf("ERROR: Creating heartbeat file - %s", err)
+		}
+		defer file.Close()
+	} else {
+		currentTime := time.Now()
+		err = os.Chtimes(*heartbeatFilePath, currentTime, currentTime)
+		if err != nil {
+			log.Fatalf("ERROR: Touching %s", err)
+		}
+	}
+	if err != nil {
+		log.Fatalf("ERROR: %s", err)
+	}
+}
+
 func main() {
 	flag.Parse()