fix: Change to use annotation when getting the hub child applications

Prev. we used labels, but when chaning the resource tracking method in
Argocd we need to adjust this function as well.

Author: darkdoc

internal/controller/argo.go

@@ -1162,14 +1162,30 @@ func syncApplication(client argoclient.Interface, app *argoapi.Application, with
 
 // returns the child applications owned by the app-of-apps parentApp
 func getChildApplications(client argoclient.Interface, parentApp *argoapi.Application) ([]argoapi.Application, error) {
-	listOptions := metav1.ListOptions{
-		LabelSelector: fmt.Sprintf("app.kubernetes.io/instance=%s", parentApp.Name),
-	}
-
-	appList, err := client.ArgoprojV1alpha1().Applications("").List(context.Background(), listOptions)
+	appList, err := client.ArgoprojV1alpha1().
+		Applications("").
+		List(context.Background(), metav1.ListOptions{})
 	if err != nil {
 		return nil, fmt.Errorf("failed to list child applications of %s: %w", parentApp.Name, err)
 	}
 
-	return appList.Items, nil
+	var result []argoapi.Application
+
+	// Build expected tracking prefix
+	// Example:
+	// multicloud-gitops-hub:argoproj.io/Application:multicloud-gitops-hub/
+	expectedPrefix := fmt.Sprintf(
+		"%s:argoproj.io/Application:%s/",
+		parentApp.Name,
+		parentApp.Namespace,
+	)
+
+	for _, app := range appList.Items { //nolint:gocritic // rangeValCopy: each iteration copies 992 bytes
+		if trackingID, ok := app.Annotations["argocd.argoproj.io/tracking-id"]; ok {
+			if strings.HasPrefix(trackingID, expectedPrefix) {
+				result = append(result, app)
+			}
+		}
+	}
+	return result, nil
 }

internal/controller/argo_test.go

@@ -1318,7 +1318,7 @@ var _ = Describe("SyncApplication", func() {
 	})
 })
 
-var _ = Describe("GetChildApplications", func() {
+var _ = Describe("getChildApplications", func() {
 	var (
 		argocdclient *argoclient.Clientset
 		namespace    string
@@ -1339,7 +1339,9 @@ var _ = Describe("GetChildApplications", func() {
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      "child-app",
 					Namespace: namespace,
-					Labels:    map[string]string{"app.kubernetes.io/instance": "parent-app"},
+					Annotations: map[string]string{
+						"argocd.argoproj.io/tracking-id": fmt.Sprintf("parent-app:argoproj.io/Application:%s/child-app", namespace),
+					},
 				},
 			}
 			_, err := argocdclient.ArgoprojV1alpha1().Applications(namespace).Create(context.Background(), childApp, metav1.CreateOptions{})
@@ -2216,8 +2218,8 @@ var _ = Describe("getChildApplications", func() {
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      "child-app",
 					Namespace: "openshift-gitops",
-					Labels: map[string]string{
-						"app.kubernetes.io/instance": "parent-app",
+					Annotations: map[string]string{
+						"argocd.argoproj.io/tracking-id": "parent-app:argoproj.io/Application:openshift-gitops/child-app",
 					},
 				},
 			}