Capture os signals to gracefully shutdown fission components (#2261)

- Currently, fission components don't handle shutdown signals.
So we don't get any to do the required cleanup before the fission process
exits. Adding signal capture process with cancelling context so
that all dependent processes stop working when the process gets term
signal.
- Set log level to error in otel shutdown function

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/mqtrigger/scalermanager.go

@@ -149,7 +149,7 @@ func mqTriggerEventHandlers(logger *zap.Logger, kubeClient *kubernetes.Clientset
 
 // StartScalerManager watches for changes in MessageQueueTrigger and,
 // Based on changes, it Creates, Updates and Deletes Objects of Kind ScaledObjects, AuthenticationTriggers and Deployments
-func StartScalerManager(logger *zap.Logger, routerURL string) error {
+func StartScalerManager(ctx context.Context, logger *zap.Logger, routerURL string) error {
 	fissionClient, kubeClient, _, _, err := crd.MakeFissionClient()
 	if err != nil {
 		return err
@@ -161,7 +161,7 @@ func StartScalerManager(logger *zap.Logger, routerURL string) error {
 	informerFactory := genInformer.NewSharedInformerFactory(fissionClient, time.Minute*30)
 	mqTriggerInformer := informerFactory.Core().V1().MessageQueueTriggers().Informer()
 	mqTriggerInformer.AddEventHandler(mqTriggerEventHandlers(logger, kubeClient, routerURL))
-	mqTriggerInformer.Run(context.Background().Done())
+	mqTriggerInformer.Run(ctx.Done())
 	return nil
 }