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.

fission-bundle/main.go

@@ -10,6 +10,7 @@ import (
 	"github.com/fission/fission/logger"
 	"github.com/fission/fission/poolmgr"
 	"github.com/fission/fission/router"
+	"github.com/fission/fission/timer"
 )
 
 func runController(port int, etcdUrl string, filepath string) {
@@ -53,6 +54,13 @@ func runLogger() {
 	log.Fatalf("Error: Logger exited.")
 }
 
+func runTimer(controllerUrl, routerUrl string) {
+	err := timer.Start(controllerUrl, routerUrl)
+	if err != nil {
+		log.Fatalf("Error starting timer: %v", err)
+	}
+}
+
 func getPort(portArg interface{}) int {
 	portArgStr := portArg.(string)
 	port, err := strconv.Atoi(portArgStr)
@@ -87,6 +95,7 @@ Usage:
   fission-bundle --poolmgrPort=<port> [--controllerUrl=<url> --namespace=<namespace>]
   fission-bundle --kubewatcher [--controllerUrl=<url> --routerUrl=<url>]
   fission-bundle --logger
+  fission-bundle --timer [--controllerUrl=<url> --routerUrl=<url>]
 Options:
   --controllerPort=<port>  Port that the controller should listen on.
   --routerPort=<port>      Port that the router should listen on.
@@ -99,6 +108,7 @@ Options:
   --namespace=<namespace>  Kubernetes namespace in which to run function containers. Defaults to 'fission-function'.
   --kubewatcher            Start Kubernetes events watcher.
   --logger                 Start logger.
+  --timer 		           Start Timer.
 `
 	arguments, err := docopt.Parse(usage, nil, true, "fission-bundle", false)
 	if err != nil {
@@ -135,5 +145,9 @@ Options:
 		runLogger()
 	}
 
+	if arguments["--timer"] == true {
+		runTimer(controllerUrl, routerUrl)
+	}
+
 	select {}
 }