add initial version of Grafana updater

grafana-watcher/main.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+	"path/filepath"
+
+	fsnotify "gopkg.in/fsnotify.v1"
+
+	"github.com/coreos/kube-prometheus/grafana-watcher/grafana"
+	"github.com/coreos/kube-prometheus/grafana-watcher/updater"
+)
+
+var (
+	watchDir   = flag.String("watch-dir", "", "The directory the ConfigMap is mounted into to watch for updates.")
+	grafanaUrl = flag.String("grafana-url", "", "The url to issue requests to update dashboards to.")
+)
+
+type volumeWatcher struct {
+	watchDir string
+	handlers []updater.Updater
+}
+
+func newVolumeWatcher(d string) *volumeWatcher {
+	return &volumeWatcher{
+		watchDir: d,
+	}
+}
+
+func (w *volumeWatcher) AddEventHandler(handler updater.Updater) {
+	w.handlers = append(w.handlers, handler)
+}
+
+func (w *volumeWatcher) Run() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer watcher.Close()
+
+	done := make(chan bool)
+	go func() {
+		for {
+			select {
+			case event := <-watcher.Events:
+				if event.Op&fsnotify.Create == fsnotify.Create {
+					if filepath.Base(event.Name) == "..data" {
+						log.Println("ConfigMap modified")
+						for _, h := range w.handlers {
+							err := h.OnModify()
+							if err != nil {
+								log.Println("error:", err)
+							}
+						}
+					}
+				}
+			case err := <-watcher.Errors:
+				log.Println("error:", err)
+			}
+		}
+	}()
+
+	log.Println("Starting...")
+	err = watcher.Add(*watchDir)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	<-done
+}
+
+func main() {
+	flag.Parse()
+
+	if *watchDir == "" {
+		log.Println("Missing watch-dir\n")
+		flag.Usage()
+		os.Exit(1)
+	}
+	if *grafanaUrl == "" {
+		log.Println("Missing grafana-url\n")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	g := grafana.New(*grafanaUrl)
+	du := updater.NewGrafanaDashboardUpdater(g.Dashboards(), filepath.Join(*watchDir, "*-dashboard.json"))
+	//su := updater.NewGrafanaSourceUpdater(g.Sources(), filepath.Join(*watchDir, "*-source.json"))
+	w := newVolumeWatcher(*watchDir)
+	w.AddEventHandler(du)
+	//w.AddEventHandler(su)
+
+	w.Run()
+}