manager: fix checkpoint

pkg/manager/manager.go

@@ -51,11 +51,11 @@ type Status struct {
 }
 
 type WorkerCheckPoint struct {
-	LastInvokeTime time.Time
+	LastInvokeTime time.Time `json:"last_invoke_time"`
 }
 
 type CheckPoint struct {
-	workerInfo map[string]WorkerCheckPoint
+	WorkerInfo map[string]WorkerCheckPoint `json:"worker_info"`
 }
 
 // fromCheckpoint laods last invoke time from json
@@ -89,7 +89,7 @@ func NewManager(config *config.Config) (*Manager, error) {
 	if err != nil {
 		logger.Info("failed to parse checkpoint file")
 	} else {
-		for worker, info := range checkpoint.workerInfo {
+		for worker, info := range checkpoint.WorkerInfo {
 			workersLastInvokeTime[worker] = info.LastInvokeTime
 		}
 	}
@@ -120,9 +120,18 @@ func NewManager(config *config.Config) (*Manager, error) {
 }
 
 func (m *Manager) checkpoint() error {
-	file, _ := json.MarshalIndent(m.workersLastInvokeTime, "", "  ")
+	ckptObj := &CheckPoint{WorkerInfo: make(map[string]WorkerCheckPoint)}
+	for k, t := range m.workersLastInvokeTime {
+		ckptObj.WorkerInfo[k] = WorkerCheckPoint{
+			LastInvokeTime: t,
+		}
+	}
+	file, err := json.MarshalIndent(ckptObj, "", "  ")
+	if err != nil {
+		return err
+	}
 	ckpt := fmt.Sprintf("%s.tmp", m.config.Checkpoint)
-	err := ioutil.WriteFile(ckpt, file, 0644)
+	err = ioutil.WriteFile(ckpt, file, 0644)
 	if err != nil {
 		return err
 	}
@@ -184,6 +193,7 @@ func (m *Manager) Run() {
 		}).Debugf("Calling RunSync() to w %s", w.GetConfig()["name"])
 		go w.RunSync()
 	}
+	m.checkpoint()
 	for {
 		// wait until config.Interval seconds has elapsed
 		select {