Allow empty backend

.golangci.yaml

@@ -137,6 +137,8 @@ linters-settings:
         alias: kctrl
       - pkg: sigs.k8s.io/controller-runtime/pkg/log
         alias: kctrllog
+      - pkg: sigs.k8s.io/controller-runtime/pkg/client
+        alias: kclient
       - pkg: k8s.io/api/autoscaling/v1
         alias: kautoscalingv1
       - pkg: k8s.io/api/autoscaling/v2

api/operator/v1alpha1/eventing_types.go

@@ -33,7 +33,7 @@ const (
 	StateProcessing string = "Processing"
 	StateWarning    string = "Warning"
 
-	ConditionNATSAvailable            ConditionType = "NATSAvailable"
+	ConditionBackendAvailable         ConditionType = "BackendAvailable"
 	ConditionPublisherProxyReady      ConditionType = "PublisherProxyReady"
 	ConditionWebhookReady             ConditionType = "WebhookReady"
 	ConditionSubscriptionManagerReady ConditionType = "SubscriptionManagerReady"
@@ -48,8 +48,9 @@ const (
 	ConditionReasonDeployed                   ConditionReason = "Deployed"
 	ConditionReasonDeployedFailed             ConditionReason = "DeployFailed"
 	ConditionReasonDeploymentStatusSyncFailed ConditionReason = "DeploymentStatusSyncFailed"
-	ConditionReasonNATSAvailable              ConditionReason = "Available"
-	ConditionReasonNATSNotAvailable           ConditionReason = "NotAvailable"
+	ConditionReasonNATSAvailable              ConditionReason = "NATSAvailable"
+	ConditionReasonNATSNotAvailable           ConditionReason = "NATSUnavailable"
+	ConditionReasonBackendNotSpecified        ConditionReason = "BackendNotSpecified"
 	ConditionReasonForbidden                  ConditionReason = "Forbidden"
 	ConditionReasonWebhookFailed              ConditionReason = "WebhookFailed"
 	ConditionReasonWebhookReady               ConditionReason = "Ready"
@@ -63,6 +64,7 @@ const (
 	ConditionPublisherProxyProcessingMessage   = "Eventing publisher proxy deployment is in progress"
 	ConditionSubscriptionManagerReadyMessage   = "Subscription manager is ready"
 	ConditionSubscriptionManagerStoppedMessage = "Subscription manager is stopped"
+	ConditionBackendNotSpecifiedMessage        = "Backend config is not provided. Please specify a backend."
 
 	// subscription manager reasons.
 	ConditionReasonEventMeshSubManagerReady      ConditionReason = "EventMeshSubscriptionManagerReady"
@@ -82,7 +84,8 @@ type Eventing struct {
 	kmetav1.TypeMeta   `json:",inline"`
 	kmetav1.ObjectMeta `json:"metadata,omitempty"`
 
-	// +kubebuilder:default:={backend:{type:"NATS", config:{natsStreamStorageType:"File", natsStreamReplicas:3, natsStreamMaxSize:"700Mi", natsMaxMsgsPerTopic:1000000}}, logging:{logLevel:Info}, publisher:{replicas:{min:2,max:2}, resources:{limits:{cpu:"500m",memory:"512Mi"}, requests:{cpu:"40m",memory:"256Mi"}}}}
+	// +kubebuilder:default:={logging:{logLevel:Info}, publisher:{replicas:{min:2,max:2}, resources:{limits:{cpu:"500m",memory:"512Mi"}, requests:{cpu:"40m",memory:"256Mi"}}}}
+	// +kubebuilder:validation:XValidation:rule="!(oldSelf!=null && has(oldSelf.backend)) || has(self.backend)", message="backend config cannot be deleted"
 	Spec   EventingSpec   `json:"spec,omitempty"`
 	Status EventingStatus `json:"status,omitempty"`
 }
@@ -98,9 +101,8 @@ type EventingStatus struct {
 // EventingSpec defines the desired state of Eventing.
 type EventingSpec struct {
 	// Backend defines the active backend used by Eventing.
-	// +kubebuilder:default:={type:"NATS", config:{natsStreamStorageType:"File", natsStreamReplicas:3, natsStreamMaxSize:"700Mi", natsMaxMsgsPerTopic:1000000}}
 	// +kubebuilder:validation:XValidation:rule=" (self.type != 'EventMesh') || ((self.type == 'EventMesh') && (self.config.eventMeshSecret != ''))", message="secret cannot be empty if EventMesh backend is used"
-	Backend Backend `json:"backend"`
+	Backend *Backend `json:"backend,omitempty"`
 
 	// Publisher defines the configurations for eventing-publisher-proxy.
 	// +kubebuilder:default:={replicas:{min:2,max:2}, resources:{limits:{cpu:"500m",memory:"512Mi"}, requests:{cpu:"40m",memory:"256Mi"}}}

api/operator/v1alpha1/eventing_types_test.go

@@ -19,7 +19,7 @@ func TestSyncStatusActiveBackend(t *testing.T) {
 			name: "it should set ActiveBackend to NATS",
 			givenEventing: &Eventing{
 				Spec: EventingSpec{
-					Backend: Backend{Type: NatsBackendType},
+					Backend: &Backend{Type: NatsBackendType},
 				},
 				Status: EventingStatus{},
 			},
@@ -29,7 +29,7 @@ func TestSyncStatusActiveBackend(t *testing.T) {
 			name: "it should set ActiveBackend to EventMesh",
 			givenEventing: &Eventing{
 				Spec: EventingSpec{
-					Backend: Backend{Type: EventMeshBackendType},
+					Backend: &Backend{Type: EventMeshBackendType},
 				},
 				Status: EventingStatus{},
 			},
@@ -65,7 +65,7 @@ func TestIsSpecBackendTypeChanged(t *testing.T) {
 			name: "it should return false if backend is not changed",
 			givenEventing: &Eventing{
 				Spec: EventingSpec{
-					Backend: Backend{Type: NatsBackendType},
+					Backend: &Backend{Type: NatsBackendType},
 				},
 				Status: EventingStatus{
 					ActiveBackend: NatsBackendType,
@@ -77,7 +77,7 @@ func TestIsSpecBackendTypeChanged(t *testing.T) {
 			name: "it should return true if backend is changed",
 			givenEventing: &Eventing{
 				Spec: EventingSpec{
-					Backend: Backend{Type: NatsBackendType},
+					Backend: &Backend{Type: NatsBackendType},
 				},
 				Status: EventingStatus{
 					ActiveBackend: EventMeshBackendType,

api/operator/v1alpha1/status.go

@@ -8,11 +8,11 @@ import (
 	kmetav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-func (es *EventingStatus) UpdateConditionNATSAvailable(status kmetav1.ConditionStatus, reason ConditionReason,
+func (es *EventingStatus) UpdateConditionBackendAvailable(status kmetav1.ConditionStatus, reason ConditionReason,
 	message string,
 ) {
 	condition := kmetav1.Condition{
-		Type:               string(ConditionNATSAvailable),
+		Type:               string(ConditionBackendAvailable),
 		Status:             status,
 		LastTransitionTime: kmetav1.Now(),
 		Reason:             string(reason),
@@ -80,7 +80,7 @@ func (es *EventingStatus) SetSubscriptionManagerReadyConditionToTrue() {
 
 func (es *EventingStatus) SetStateReady() {
 	es.State = StateReady
-	es.UpdateConditionNATSAvailable(kmetav1.ConditionTrue, ConditionReasonNATSAvailable, ConditionNATSAvailableMessage)
+	es.UpdateConditionBackendAvailable(kmetav1.ConditionTrue, ConditionReasonNATSAvailable, ConditionNATSAvailableMessage)
 	es.UpdateConditionPublisherProxyReady(kmetav1.ConditionTrue, ConditionReasonDeployed, ConditionPublisherProxyReadyMessage)
 }
 
@@ -89,7 +89,7 @@ func (ns *EventingStatus) SetStateWarning() {
 }
 
 func (es *EventingStatus) SetNATSAvailableConditionToTrue() {
-	es.UpdateConditionNATSAvailable(kmetav1.ConditionTrue, ConditionReasonNATSAvailable, ConditionNATSAvailableMessage)
+	es.UpdateConditionBackendAvailable(kmetav1.ConditionTrue, ConditionReasonNATSAvailable, ConditionNATSAvailableMessage)
 }
 
 func (es *EventingStatus) SetSubscriptionManagerReadyConditionToFalse(reason ConditionReason, message string) {

config/crd/bases/operator.kyma-project.io_eventings.yaml

@@ -47,13 +47,6 @@ spec:
             type: object
           spec:
             default:
-              backend:
-                config:
-                  natsMaxMsgsPerTopic: 1000000
-                  natsStreamMaxSize: 700Mi
-                  natsStreamReplicas: 3
-                  natsStreamStorageType: File
-                type: NATS
               logging:
                 logLevel: Info
               publisher:
@@ -67,21 +60,14 @@ spec:
                   requests:
                     cpu: 40m
                     memory: 256Mi
-            description: EventingSpec defines the desired state of Eventing
+            description: EventingSpec defines the desired state of Eventing.
             properties:
               annotations:
                 additionalProperties:
                   type: string
                 description: Annotations allows to add annotations to resources.
                 type: object
               backend:
-                default:
-                  config:
-                    natsMaxMsgsPerTopic: 1000000
-                    natsStreamMaxSize: 700Mi
-                    natsStreamReplicas: 3
-                    natsStreamStorageType: File
-                  type: NATS
                 description: Backend defines the active backend used by Eventing.
                 properties:
                   config:
@@ -261,11 +247,12 @@ spec:
                         type: object
                     type: object
                 type: object
-            required:
-            - backend
             type: object
+            x-kubernetes-validations:
+            - message: backend config cannot be deleted
+              rule: '!(oldSelf!=null && has(oldSelf.backend)) || has(self.backend)'
           status:
-            description: EventingStatus defines the observed state of Eventing
+            description: EventingStatus defines the observed state of Eventing.
             properties:
               activeBackend:
                 type: string

docs/user/02-configuration.md

@@ -31,7 +31,7 @@ Use the following sample CRs as guidance. Each can be applied immediately when y
 | Parameter                                                | Type                  | Description                                                                                                                                                                                                                                                                                                                                |
 |----------------------------------------------------------|-----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | **annotations**                                          | map\[string\]string   | Annotations allows to add annotations to resources.                                                                                                                                                                                                                                                                                        |
-| **backend** (required)                                   | object                | Backend defines the active backend used by Eventing.                                                                                                                                                                                                                                                                                       |
+| **backend**                                    | object                | Backend defines the active backend used by Eventing.                                                                                                                                                                                                                                                                                       |
 | **backend.​config**                               | object                | Config defines configuration for eventing backend.                                                                                                                                                                                                                                                                                         |
 | **backend.​config.​domain**                | string                | Domain defines the cluster public domain used to configure the EventMesh Subscriptions and their corresponding ApiRules.                                                                                                                                                                                                                   |
 | **backend.​config.​eventMeshSecret**       | string                | EventMeshSecret defines the namespaced name of K8s Secret containing EventMesh credentials. The format of name is "namespace/name".                                                                                                                                                                                                        |

hack/e2e/common/fixtures/fixtures.go

@@ -63,7 +63,7 @@ func EventingNATSCR() *operatorv1alpha1.Eventing {
 			Namespace: NamespaceName,
 		},
 		Spec: operatorv1alpha1.EventingSpec{
-			Backend: operatorv1alpha1.Backend{
+			Backend: &operatorv1alpha1.Backend{
 				Type: "NATS",
 				Config: operatorv1alpha1.BackendConfig{
 					NATSStreamStorageType: "File",
@@ -88,7 +88,7 @@ func EventingEventMeshCR() *operatorv1alpha1.Eventing {
 			Namespace: NamespaceName,
 		},
 		Spec: operatorv1alpha1.EventingSpec{
-			Backend: operatorv1alpha1.Backend{
+			Backend: &operatorv1alpha1.Backend{
 				Type: "EventMesh",
 				Config: operatorv1alpha1.BackendConfig{
 					EventMeshSecret: fmt.Sprintf("%s/%s", EventMeshSecretNamespace, EventMeshSecretName),

internal/controller/operator/eventing/controller.go

@@ -379,6 +379,12 @@ func (r *Reconciler) handleEventingDeletion(ctx context.Context, eventing *opera
 		return kctrl.Result{}, nil
 	}
 
+	if eventing.Spec.Backend == nil {
+		// backend config can only be empty during creation and nothing is created if it is missing.
+		// Hence, eventing can be safely removed.
+		return r.removeFinalizer(ctx, eventing)
+	}
+
 	// check if subscription resources exist
 	exists, err := r.eventingManager.SubscriptionExists(ctx)
 	if err != nil {
@@ -441,6 +447,12 @@ func (r *Reconciler) handleEventingReconcile(ctx context.Context,
 
 	// set state processing if not set yet
 	r.InitStateProcessing(eventing)
+	if eventing.Spec.Backend == nil {
+		return kctrl.Result{Requeue: true}, r.syncStatusForEmptyBackend(ctx,
+			operatorv1alpha1.ConditionReasonBackendNotSpecified,
+			operatorv1alpha1.ConditionBackendNotSpecifiedMessage,
+			eventing, log)
+	}
 
 	// sync webhooks CABundle.
 	if err := r.reconcileWebhooksWithCABundle(ctx); err != nil {
@@ -514,9 +526,13 @@ func (r *Reconciler) reconcileNATSBackend(ctx context.Context, eventing *operato
 			// into CrashLoopBackOff.
 			log.Infof("NATS module not enabled, deleting publisher proxy resources")
 			delErr := r.eventingManager.DeletePublisherProxyResources(ctx, eventing)
+			if delErr != nil {
+				return kctrl.Result{}, delErr
+			}
 			// update the Eventing CR status.
 			notFoundErr := fmt.Errorf("NATS module has to be installed: %v", err)
-			return kctrl.Result{}, errors.Join(r.syncStatusWithNATSErr(ctx, eventing, notFoundErr, log), delErr)
+			return kctrl.Result{}, r.syncStatusWithNATSState(ctx, operatorv1alpha1.StateWarning, eventing,
+				notFoundErr, log)
 		}
 		return kctrl.Result{}, err
 	}
@@ -596,8 +612,19 @@ func (r *Reconciler) reconcileEventMeshBackend(ctx context.Context, eventing *op
 		return kctrl.Result{}, r.syncStatusWithSubscriptionManagerErr(ctx, eventing, apiRuleMissingErr, log)
 	}
 
+	// retrieve secret used to authenticate with EventMesh
+	eventMeshSecret, err := r.kubeClient.GetSecret(ctx, eventing.Spec.Backend.Config.EventMeshSecret)
+	if err != nil {
+		if kerrors.IsNotFound(err) {
+			return kctrl.Result{}, r.syncSubManagerStatusWithNATSState(ctx, operatorv1alpha1.StateWarning, eventing,
+				fmt.Errorf(EventMeshSecretMissingMessage), log)
+		}
+		return kctrl.Result{}, r.syncStatusWithSubscriptionManagerErr(ctx, eventing,
+			fmt.Errorf("failed to get EventMesh secret: %v", err), log)
+	}
+
 	// Start the EventMesh subscription controller
-	err = r.reconcileEventMeshSubManager(ctx, eventing)
+	err = r.reconcileEventMeshSubManager(ctx, eventing, eventMeshSecret, log)
 	if err != nil {
 		return kctrl.Result{}, r.syncStatusWithSubscriptionManagerErr(ctx, eventing, err, log)
 	}

internal/controller/operator/eventing/eventmesh.go

@@ -36,17 +36,16 @@ type oauth2Credentials struct {
 	certsURL     []byte
 }
 
-func (r *Reconciler) reconcileEventMeshSubManager(ctx context.Context, eventing *v1alpha1.Eventing) error {
+const EventMeshSecretMissingMessage = "the specified EventMesh secret is missing. Please provide the secret"
+
+func (r *Reconciler) reconcileEventMeshSubManager(ctx context.Context, eventing *v1alpha1.Eventing,
+	eventMeshSecret *kcorev1.Secret, log *zap.SugaredLogger,
+) error {
 	// gets oauth2ClientID and secret and stops the EventMesh subscription manager if changed
 	err := r.syncOauth2ClientIDAndSecret(ctx, eventing)
 	if err != nil {
 		return errors.Errorf("failed to sync OAuth secret: %v", err)
 	}
-	// retrieve secret to authenticate with EventMesh
-	eventMeshSecret, err := r.kubeClient.GetSecret(ctx, eventing.Spec.Backend.Config.EventMeshSecret)
-	if err != nil {
-		return errors.Errorf("failed to get EventMesh secret: %v", err)
-	}
 	// CreateOrUpdate deployment for publisher proxy secret
 	secretForPublisher, err := r.SyncPublisherProxySecret(ctx, eventMeshSecret)
 	if err != nil {