Enabling multi-tenancy for fission objects. (#655)

This feature allows creation of fission objects in different namespaces, in addition to retaining the existing behavior of creating fission objects in default namespace if user doesnt provide one. 
It also removes cluster admin roles for fission-fetcher and fission-builder Service Accounts and grants them only those privileges that they need.

timer/timer.go

@@ -87,17 +87,10 @@ func (timer *Timer) svc() {
 
 func (timer *Timer) syncCron(triggers []crd.TimeTrigger) error {
 	// add new triggers or update existing ones
+	triggerMap := make(map[string]bool)
 	for _, t := range triggers {
-		if item, ok := timer.triggers[t.Metadata.Name]; ok {
-			// the item exists, update the item if needed
-
-			// if both UID and ResourceVersion match, the
-			// two triggers are identical
-			if item.trigger.Metadata.UID == t.Metadata.UID &&
-				item.trigger.Metadata.ResourceVersion == t.Metadata.ResourceVersion {
-				continue
-			}
-
+		triggerMap[crd.CacheKey(&t.Metadata)] = true
+		if item, ok := timer.triggers[crd.CacheKey(&t.Metadata)]; ok {
 			// update cron if the cron spec changed
 			if item.trigger.Spec.Cron != t.Spec.Cron {
 				// if there is an cron running, stop it
@@ -109,7 +102,7 @@ func (timer *Timer) syncCron(triggers []crd.TimeTrigger) error {
 
 			item.trigger = t
 		} else {
-			timer.triggers[t.Metadata.Name] = &timerTriggerWithCron{
+			timer.triggers[crd.CacheKey(&t.Metadata)] = &timerTriggerWithCron{
 				trigger: t,
 				cron:    timer.newCron(t),
 			}
@@ -118,14 +111,7 @@ func (timer *Timer) syncCron(triggers []crd.TimeTrigger) error {
 
 	// process removed triggers
 	for k, v := range timer.triggers {
-		found := false
-		for _, t := range triggers {
-			if t.Metadata.Name == k {
-				found = true
-				break
-			}
-		}
-		if !found {
+		if _, found := triggerMap[k]; !found {
 			if v.cron != nil {
 				v.cron.Stop()
 				log.Printf("Cron for time trigger %s stopped", v.trigger.Metadata.Name)
@@ -143,7 +129,11 @@ func (timer *Timer) newCron(t crd.TimeTrigger) *cron.Cron {
 		headers := map[string]string{
 			"X-Fission-Timer-Name": t.Metadata.Name,
 		}
-		(*timer.publisher).Publish("", headers, fission.UrlForFunction(t.Spec.FunctionReference.Name))
+
+		// with the addition of multi-tenancy, the users can create functions in any namespace. however,
+		// the triggers can only be created in the same namespace as the function.
+		// so essentially, function namespace = trigger namespace.
+		(*timer.publisher).Publish("", headers, fission.UrlForFunction(t.Spec.FunctionReference.Name, t.Metadata.Namespace))
 	})
 	c.Start()
 	log.Printf("Add new cron for time trigger %v", t.Metadata.Name)