feat(basic-pull): add custom destination annotations for Application (#161)

Introduce two optional annotations to override the default destination
behavior in the basic pull model:

- apps.open-cluster-management.io/destination-name
- apps.open-cluster-management.io/destination-server

When either annotation is present, the controller uses the provided
value instead of the hardcoded default. This allows users to specify
custom destination configurations like in-cluster for destination
name or alternative server URLs.

Signed-off-by: Mike Ng <ming@redhat.com>

Author: mikeshng

internal/basic/application/application_controller.go

@@ -39,6 +39,10 @@ const (
 	AnnotationKeyOCMManagedCluster = "apps.open-cluster-management.io/ocm-managed-cluster"
 	// Application annotation that dictates which managed cluster namespace this Application should be pulled to
 	AnnotationKeyOCMManagedClusterAppNamespace = "apps.open-cluster-management.io/ocm-managed-cluster-app-namespace"
+	// Application annotation that allows specifying a custom destination name (ie, in-cluster)
+	AnnotationKeyDestinationName = "apps.open-cluster-management.io/destination-name"
+	// Application annotation that allows specifying a custom destination server URL (ie, https://kubernetes.default.svc)
+	AnnotationKeyDestinationServer = "apps.open-cluster-management.io/destination-server"
 	// Application and ManifestWork annotation that shows which ApplicationSet is the grand parent of this work
 	AnnotationKeyAppSet = "apps.open-cluster-management.io/hosting-applicationset"
 	// Application annotation that enables the skip reconcilation of an application

internal/basic/application/helper.go

@@ -109,7 +109,7 @@ func getAppSetOwnerName(ownerRefs []metav1.OwnerReference) string {
 // prepareApplicationForWorkPayload modifies the Application:
 // - reset the meta
 // - set the namespace value
-// - ensures the Application Destination is set to in-cluster resource deployment
+// - ensures the Application Destination is set based on annotations or defaults to server KubernetesInternalAPIServerAddr
 // - ensures the operation field is also set if present
 func prepareApplicationForWorkPayload(application *unstructured.Unstructured) unstructured.Unstructured {
 	newApp := &unstructured.Unstructured{}
@@ -130,10 +130,27 @@ func prepareApplicationForWorkPayload(application *unstructured.Unstructured) un
 	// set the spec field
 	if newSpec, ok := application.Object["spec"].(map[string]interface{}); ok {
 		if destination, ok := newSpec["destination"].(map[string]interface{}); ok {
-			// empty the name
-			destination["name"] = ""
-			// always set for in-cluster destination
-			destination["server"] = KubernetesInternalAPIServerAddr
+			annos := application.GetAnnotations()
+			customName, hasCustomName := annos[AnnotationKeyDestinationName]
+			customServer, hasCustomServer := annos[AnnotationKeyDestinationServer]
+
+			if hasCustomName || hasCustomServer {
+				// custom annotations present - only set the fields that have annotations
+				if hasCustomName {
+					destination["name"] = customName
+				} else {
+					destination["name"] = ""
+				}
+				if hasCustomServer {
+					destination["server"] = customServer
+				} else {
+					destination["server"] = ""
+				}
+			} else {
+				// default behavior
+				destination["name"] = ""
+				destination["server"] = KubernetesInternalAPIServerAddr
+			}
 		}
 		newApp.Object["spec"] = newSpec
 	}
@@ -152,7 +169,9 @@ func prepareApplicationForWorkPayload(application *unstructured.Unstructured) un
 	for key, value := range application.GetAnnotations() {
 		if key != AnnotationKeyOCMManagedCluster &&
 			key != AnnotationKeyOCMManagedClusterAppNamespace &&
-			key != AnnotationKeyAppSkipReconcile {
+			key != AnnotationKeyAppSkipReconcile &&
+			key != AnnotationKeyDestinationName &&
+			key != AnnotationKeyDestinationServer {
 			annotations[key] = value
 		}
 	}

internal/basic/application/helper_test.go

@@ -330,6 +330,46 @@ func Test_prepareApplicationForWorkPayload(t *testing.T) {
 		},
 	}
 
+	// Create an application with custom destination-name annotation
+	appWithDestName := &unstructured.Unstructured{}
+	appWithDestName.SetGroupVersionKind(schema.GroupVersionKind{
+		Group:   "argoproj.io",
+		Version: "v1alpha1",
+		Kind:    "Application",
+	})
+	appWithDestName.SetName("app2")
+	appWithDestName.SetNamespace("argocd")
+	appWithDestName.SetFinalizers([]string{"app2-final"})
+	appWithDestName.SetAnnotations(map[string]string{
+		AnnotationKeyDestinationName: "in-cluster",
+	})
+	appWithDestName.Object["spec"] = map[string]interface{}{
+		"destination": map[string]interface{}{
+			"name":   "originalName",
+			"server": "originalServer",
+		},
+	}
+
+	// Create an application with custom destination-server annotation
+	appWithDestServer := &unstructured.Unstructured{}
+	appWithDestServer.SetGroupVersionKind(schema.GroupVersionKind{
+		Group:   "argoproj.io",
+		Version: "v1alpha1",
+		Kind:    "Application",
+	})
+	appWithDestServer.SetName("app3")
+	appWithDestServer.SetNamespace("argocd")
+	appWithDestServer.SetFinalizers([]string{"app3-final"})
+	appWithDestServer.SetAnnotations(map[string]string{
+		AnnotationKeyDestinationServer: "https://custom-server:6443",
+	})
+	appWithDestServer.Object["spec"] = map[string]interface{}{
+		"destination": map[string]interface{}{
+			"name":   "originalName",
+			"server": "originalServer",
+		},
+	}
+
 	type args struct {
 		application *unstructured.Unstructured
 	}
@@ -339,7 +379,7 @@ func Test_prepareApplicationForWorkPayload(t *testing.T) {
 		want *unstructured.Unstructured
 	}{
 		{
-			name: "modified app",
+			name: "default behavior - no custom destination annotations",
 			args: args{application: app},
 			want: func() *unstructured.Unstructured {
 				expectedApp := &unstructured.Unstructured{}
@@ -384,6 +424,54 @@ func Test_prepareApplicationForWorkPayload(t *testing.T) {
 				return expectedApp
 			}(),
 		},
+		{
+			name: "custom destination-name annotation",
+			args: args{application: appWithDestName},
+			want: func() *unstructured.Unstructured {
+				expectedApp := &unstructured.Unstructured{}
+				expectedApp.SetGroupVersionKind(schema.GroupVersionKind{
+					Group:   "argoproj.io",
+					Version: "v1alpha1",
+					Kind:    "Application",
+				})
+				expectedApp.SetName("app2")
+				expectedApp.SetNamespace("argocd")
+				expectedApp.SetFinalizers([]string{"app2-final"})
+				expectedApp.SetLabels(map[string]string{})
+				expectedApp.SetAnnotations(map[string]string{})
+				expectedApp.Object["spec"] = map[string]interface{}{
+					"destination": map[string]interface{}{
+						"name":   "in-cluster",
+						"server": "",
+					},
+				}
+				return expectedApp
+			}(),
+		},
+		{
+			name: "custom destination-server annotation",
+			args: args{application: appWithDestServer},
+			want: func() *unstructured.Unstructured {
+				expectedApp := &unstructured.Unstructured{}
+				expectedApp.SetGroupVersionKind(schema.GroupVersionKind{
+					Group:   "argoproj.io",
+					Version: "v1alpha1",
+					Kind:    "Application",
+				})
+				expectedApp.SetName("app3")
+				expectedApp.SetNamespace("argocd")
+				expectedApp.SetFinalizers([]string{"app3-final"})
+				expectedApp.SetLabels(map[string]string{})
+				expectedApp.SetAnnotations(map[string]string{})
+				expectedApp.Object["spec"] = map[string]interface{}{
+					"destination": map[string]interface{}{
+						"name":   "",
+						"server": "https://custom-server:6443",
+					},
+				}
+				return expectedApp
+			}(),
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {