Extend worker.Worker to support periodic job registration

worker/simple.go

@@ -196,6 +196,11 @@ func (w *Simple) PerformIn(job Job, d time.Duration) error {
 	return nil
 }
 
+// RegisterPeriodic is currently a no-op and should be implemented
+func (w *Simple) RegisterPeriodic(cronSpec, jobName string, h Handler) error {
+	return nil
+}
+
 // SimpleLogger is used by the Simple worker to write logs
 type SimpleLogger interface {
 	Debugf(string, ...interface{})

worker/worker.go

@@ -24,6 +24,8 @@ type Worker interface {
 	PerformIn(Job, time.Duration) error
 	// Register a Handler
 	Register(string, Handler) error
+	// RegisterPeriodic performs a job periodically according to the provided cron spec
+	RegisterPeriodic(cronSpec, jobName string, h Handler) error
 }
 
 /* TODO(sio4): #road-to-v1 - redefine Worker interface clearer