Ability to retain specialised pods for poolmanager functions (#2830)

- added retainPods flag to take in the number of specialized pods to retain
- add retainPods in both the create function and update function command
- modify crd keys to be typed instead of string
- keep track of function generation in case of update function operation
- add delete handler function to make sure specialized pods are deleted in case function is deleted

---------

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>
Signed-off-by: Pranoy Kundu <pranoy1998k@gmail.com>
Co-authored-by: Pranoy Kundu <pranoy1998k@gmail.com>

pkg/timer/timer.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/robfig/cron/v3"
 	"go.uber.org/zap"
+	"k8s.io/apimachinery/pkg/types"
 
 	fv1 "github.com/fission/fission/pkg/apis/core/v1"
 	"github.com/fission/fission/pkg/publisher"
@@ -36,7 +37,7 @@ const (
 type (
 	Timer struct {
 		logger    *zap.Logger
-		triggers  map[string]*timerTriggerWithCron
+		triggers  map[types.UID]*timerTriggerWithCron
 		publisher *publisher.Publisher
 	}
 
@@ -49,7 +50,7 @@ type (
 func MakeTimer(logger *zap.Logger, publisher publisher.Publisher) *Timer {
 	timer := &Timer{
 		logger:    logger.Named("timer"),
-		triggers:  make(map[string]*timerTriggerWithCron),
+		triggers:  make(map[types.UID]*timerTriggerWithCron),
 		publisher: &publisher,
 	}
 	return timer

pkg/timer/timerSync.go

@@ -63,7 +63,7 @@ func (ws *TimerSync) AddUpdateTimeTrigger(timeTrigger *fv1.TimeTrigger) {
 
 	ws.logger.Debug("cron event")
 
-	if item, ok := ws.timer.triggers[crd.CacheKeyUID(&timeTrigger.ObjectMeta)]; ok {
+	if item, ok := ws.timer.triggers[crd.CacheKeyUIDFromMeta(&timeTrigger.ObjectMeta)]; ok {
 		if item.cron != nil {
 			item.cron.Stop()
 		}
@@ -71,7 +71,7 @@ func (ws *TimerSync) AddUpdateTimeTrigger(timeTrigger *fv1.TimeTrigger) {
 		item.cron = ws.timer.newCron(*timeTrigger)
 		logger.Debug("cron updated")
 	} else {
-		ws.timer.triggers[crd.CacheKeyUID(&timeTrigger.ObjectMeta)] = &timerTriggerWithCron{
+		ws.timer.triggers[crd.CacheKeyUIDFromMeta(&timeTrigger.ObjectMeta)] = &timerTriggerWithCron{
 			trigger: *timeTrigger,
 			cron:    ws.timer.newCron(*timeTrigger),
 		}
@@ -82,12 +82,12 @@ func (ws *TimerSync) AddUpdateTimeTrigger(timeTrigger *fv1.TimeTrigger) {
 func (ws *TimerSync) DeleteTimeTrigger(timeTrigger *fv1.TimeTrigger) {
 	logger := ws.logger.With(zap.String("trigger_name", timeTrigger.Name), zap.String("trigger_namespace", timeTrigger.Namespace))
 
-	if item, ok := ws.timer.triggers[crd.CacheKeyUID(&timeTrigger.ObjectMeta)]; ok {
+	if item, ok := ws.timer.triggers[crd.CacheKeyUIDFromMeta(&timeTrigger.ObjectMeta)]; ok {
 		if item.cron != nil {
 			item.cron.Stop()
 			logger.Info("cron for time trigger stopped")
 		}
-		delete(ws.timer.triggers, crd.CacheKeyUID(&timeTrigger.ObjectMeta))
+		delete(ws.timer.triggers, crd.CacheKeyUIDFromMeta(&timeTrigger.ObjectMeta))
 		logger.Debug("cron deleted")
 	}
 }