Add Time Trigger API and client (#153) (#161)

This change adds a timer trigger API, client, and implementation.  Users can trigger a function with a cron-compatible string. 

This change also moves the publisher interface and webhook-based publisher implementation out of kubewatcher and into a separate `publisher` package.

controller/api.go

@@ -32,6 +32,7 @@ import (
 type API struct {
 	FunctionStore
 	HTTPTriggerStore
+	TimeTriggerStore
 	EnvironmentStore
 	WatchStore
 }
@@ -40,6 +41,7 @@ func MakeAPI(rs *ResourceStore) *API {
 	api := &API{
 		FunctionStore:    FunctionStore{ResourceStore: *rs},
 		HTTPTriggerStore: HTTPTriggerStore{ResourceStore: *rs},
+		TimeTriggerStore: TimeTriggerStore{ResourceStore: *rs},
 		EnvironmentStore: EnvironmentStore{ResourceStore: *rs},
 		WatchStore:       WatchStore{ResourceStore: *rs},
 	}
@@ -95,6 +97,12 @@ func (api *API) Serve(port int) {
 	r.HandleFunc("/v1/watches/{watch}", api.WatchApiUpdate).Methods("PUT")
 	r.HandleFunc("/v1/watches/{watch}", api.WatchApiDelete).Methods("DELETE")
 
+	r.HandleFunc("/v1/triggers/time", api.TimeTriggerApiList).Methods("GET")
+	r.HandleFunc("/v1/triggers/time", api.TimeTriggerApiCreate).Methods("POST")
+	r.HandleFunc("/v1/triggers/time/{timeTrigger}", api.TimeTriggerApiGet).Methods("GET")
+	r.HandleFunc("/v1/triggers/time/{timeTrigger}", api.TimeTriggerApiUpdate).Methods("PUT")
+	r.HandleFunc("/v1/triggers/time/{timeTrigger}", api.TimeTriggerApiDelete).Methods("DELETE")
+
 	address := fmt.Sprintf(":%v", port)
 
 	log.WithFields(log.Fields{"port": port}).Info("Server started")