Add more logging

Author: jwilder

docker-gen.go

@@ -29,7 +29,7 @@ var (
 )
 
 type Event struct {
-	ContainerId string `json:"id"`
+	ContainerID string `json:"id"`
 	Status      string `json:"status"`
 	Image       string `json:"from"`
 }
@@ -118,9 +118,11 @@ func generateFromContainers(client *docker.Client) {
 	}
 	for _, config := range configs.Config {
 		changed := generateFile(config, containers)
-		if changed {
-			runNotifyCmd(config)
+		if !changed {
+			log.Printf("Contents of %s did not change. Skipping notification '%s'", config.Dest, config.NotifyCmd)
+			continue
 		}
+		runNotifyCmd(config)
 	}
 }
 
@@ -129,12 +131,13 @@ func runNotifyCmd(config Config) {
 		return
 	}
 
+	log.Printf("Running '%s'", config.NotifyCmd)
 	args := strings.Split(config.NotifyCmd, " ")
 	cmd := exec.Command(args[0], args[1:]...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		log.Printf("error running notify command: %s, %s\n", config.NotifyCmd, err)
-		fmt.Println(string(out))
+		log.Print(string(out))
 	}
 }
 
@@ -153,6 +156,7 @@ func generateAtInterval(client *docker.Client, configs ConfigFile) {
 			continue
 		}
 
+		log.Printf("Generating every %d seconds", config.Interval)
 		wg.Add(1)
 		ticker := time.NewTicker(time.Duration(config.Interval) * time.Second)
 		quit := make(chan struct{})
@@ -187,13 +191,17 @@ func generateFromEvents(client *docker.Client, configs ConfigFile) {
 
 	wg.Add(1)
 	defer wg.Done()
+	log.Println("Watching docker events")
 	eventChan := getEvents()
 	for {
 		event := <-eventChan
+
 		if event == nil {
-			return
+			continue
 		}
+
 		if event.Status == "start" || event.Status == "stop" || event.Status == "die" {
+			log.Printf("Received event %s for container %s", event.Status, event.ContainerID[:12])
 			generateFromContainers(client)
 		}
 	}

docker_client.go

@@ -115,6 +115,7 @@ func newConn() (*httputil.ClientConn, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	return httputil.NewClientConn(conn, nil), nil
 }
 
@@ -123,59 +124,62 @@ func getEvents() chan *Event {
 	go func() {
 		defer close(eventChan)
 
-	restart:
-
-		c, err := newConn()
-		if err != nil {
-			log.Printf("cannot connect to docker: %s\n", err)
-			time.Sleep(10 * time.Second)
-			goto restart
-		}
-		defer c.Close()
-
-		req, err := http.NewRequest("GET", "/events", nil)
-		if err != nil {
-			log.Printf("bad request for events: %s\n", err)
-			c.Close()
-			time.Sleep(10 * time.Second)
-			goto restart
-		}
+		for {
 
-		resp, err := c.Do(req)
-		if err != nil {
-			log.Printf("cannot connect to events endpoint: %s\n", err)
-			c.Close()
-			time.Sleep(10 * time.Second)
-			goto restart
-		}
-		defer resp.Body.Close()
+			c, err := newConn()
+			if err != nil {
+				log.Printf("cannot connect to docker: %s\n", err)
+				time.Sleep(10 * time.Second)
+				continue
+			}
 
-		// handle signals to stop the socket
-		sigChan := make(chan os.Signal, 1)
-		signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
-		go func() {
-			for sig := range sigChan {
-				log.Printf("received signal '%v', exiting\n", sig)
+			req, err := http.NewRequest("GET", "/events", nil)
+			if err != nil {
+				log.Printf("bad request for events: %s\n", err)
+				c.Close()
+				time.Sleep(10 * time.Second)
+				continue
+			}
 
+			resp, err := c.Do(req)
+			if err != nil {
+				log.Printf("cannot connect to events endpoint: %s\n", err)
 				c.Close()
-				close(eventChan)
-				os.Exit(0)
+				time.Sleep(10 * time.Second)
+				continue
 			}
-		}()
 
-		dec := json.NewDecoder(resp.Body)
-		for {
-			var event *Event
-			if err := dec.Decode(&event); err != nil {
-				if err == io.EOF {
+			// handle signals to stop the socket
+			sigChan := make(chan os.Signal, 1)
+			signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
+			go func() {
+				for sig := range sigChan {
+					log.Printf("received signal '%v', exiting\n", sig)
+
+					c.Close()
+					resp.Body.Close()
+					close(eventChan)
+					os.Exit(0)
+				}
+			}()
+
+			dec := json.NewDecoder(resp.Body)
+			for {
+				var event *Event
+				if err := dec.Decode(&event); err != nil || event.Status == "" {
+					if err == io.EOF || event.Status == "" {
+						log.Printf("connection closed")
+						break
+					}
+					log.Printf("cannot decode json: %s\n", err)
+					c.Close()
+					resp.Body.Close()
 					break
 				}
-				log.Printf("cannot decode json: %s\n", err)
-				goto restart
+
+				eventChan <- event
 			}
-			eventChan <- event
 		}
-		log.Printf("closing event channel\n")
 	}()
 	return eventChan
 }

template.go

@@ -91,6 +91,7 @@ func generateFile(config Config, containers []*RuntimeContainer) bool {
 			if err != nil {
 				log.Fatalf("unable to create dest file %s: %s\n", config.Dest, err)
 			}
+			log.Printf("Generated '%s' from %d containers", config.Dest, len(filteredContainers))
 			return true
 		}
 		return false