From 1f5c2a64e418a870f58e922e836cc7ae76372cc4 Mon Sep 17 00:00:00 2001
From: Shwetha K <sk2@vmware.com>
Date: Mon, 30 May 2022 20:23:03 +0530
Subject: [PATCH] handled the context and goroutine internally

---
 examples/watch_resources/README.md     |  2 +-
 examples/watch_resources/watch_test.go | 12 +++---
 klient/k8s/watcher/watch.go            | 54 ++++++++++++++++----------
 3 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/examples/watch_resources/README.md b/examples/watch_resources/README.md
index 311b8843..a664a250 100644
--- a/examples/watch_resources/README.md
+++ b/examples/watch_resources/README.md
@@ -14,7 +14,7 @@ dep := appsv1.Deployment{
 			}
 
 			// watch for the deployment and triger action based on the event recieved.
-			go cl.Resources().Watch(&appsv1.DeploymentList{}, &client.ListOptions{
+			cl.Resources().Watch(&appsv1.DeploymentList{}, &client.ListOptions{
 				FieldSelector: fields.OneTermEqualSelector("metadata.name", dep.Name),
 				Namespace:     dep.Namespace}, cl.RESTConfig()).WithAddFunc(onAdd).WithDeleteFunc(onDelete).Start(ctx)
 ...
diff --git a/examples/watch_resources/watch_test.go b/examples/watch_resources/watch_test.go
index beb26f36..c868887c 100644
--- a/examples/watch_resources/watch_test.go
+++ b/examples/watch_resources/watch_test.go
@@ -44,7 +44,7 @@ func TestWatchForResources(t *testing.T) {
 			}
 
 			// watch for the deployment and triger action based on the event recieved.
-			go cl.Resources().Watch(&appsv1.DeploymentList{}, resources.WithFieldSelector(labels.FormatLabels(map[string]string{"metadata.name": dep.Name}))).
+			cl.Resources().Watch(&appsv1.DeploymentList{}, resources.WithFieldSelector(labels.FormatLabels(map[string]string{"metadata.name": dep.Name}))).
 				WithAddFunc(onAdd).WithDeleteFunc(onDelete).Start(ctx)
 
 			return ctx
@@ -96,12 +96,10 @@ func TestWatchForResourcesWithStop(t *testing.T) {
 			w = cl.Resources().Watch(&appsv1.DeploymentList{}, resources.WithFieldSelector(labels.FormatLabels(map[string]string{"metadata.name": dep.Name}))).
 				WithAddFunc(onAdd).WithDeleteFunc(onDelete)
 
-			go func() {
-				err := w.Start(ctx)
-				if err != nil {
-					t.Error(err)
-				}
-			}()
+			err = w.Start(ctx)
+			if err != nil {
+				t.Error(err)
+			}
 
 			return ctx
 		}).
diff --git a/klient/k8s/watcher/watch.go b/klient/k8s/watcher/watch.go
index c498b047..96af993e 100644
--- a/klient/k8s/watcher/watch.go
+++ b/klient/k8s/watcher/watch.go
@@ -49,6 +49,11 @@ type EventHandler interface {
 // Start triggers the registered methods based on the event received for
 // particular k8s resources
 func (e *EventHandlerFuncs) Start(ctx context.Context) error {
+	// check if context is valid and that it has not been cancelled.
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+
 	cl, err := cr.NewWithWatch(e.Cfg, cr.Options{})
 	if err != nil {
 		return err
@@ -62,28 +67,37 @@ func (e *EventHandlerFuncs) Start(ctx context.Context) error {
 	// set watcher object
 	e.watcher = w
 
-	for event := range e.watcher.ResultChan() {
-		// retrieve the event type
-		eventType := event.Type
-
-		switch eventType {
-		case watch.Added:
-			// calls AddFunc if it's not nil.
-			if e.addFunc != nil {
-				e.addFunc(event.Object)
-			}
-		case watch.Modified:
-			// calls UpdateFunc if it's not nil.
-			if e.updateFunc != nil {
-				e.updateFunc(event.Object)
-			}
-		case watch.Deleted:
-			// calls DeleteFunc if it's not nil.
-			if e.deleteFunc != nil {
-				e.deleteFunc(event.Object)
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				if ctx.Err() != nil {
+					return
+				}
+			case event := <-e.watcher.ResultChan():
+				// retrieve the event type
+				eventType := event.Type
+
+				switch eventType {
+				case watch.Added:
+					// calls AddFunc if it's not nil.
+					if e.addFunc != nil {
+						e.addFunc(event.Object)
+					}
+				case watch.Modified:
+					// calls UpdateFunc if it's not nil.
+					if e.updateFunc != nil {
+						e.updateFunc(event.Object)
+					}
+				case watch.Deleted:
+					// calls DeleteFunc if it's not nil.
+					if e.deleteFunc != nil {
+						e.deleteFunc(event.Object)
+					}
+				}
 			}
 		}
-	}
+	}()
 
 	return nil
 }