Creating extension point for kubernetesFetcher

Signed-off-by: Andres Mauricio Gomez P <andmagom@outlook.com>

plugins/kubernetes-backend/package.json

@@ -90,6 +90,8 @@
     "@backstage/backend-app-api": "workspace:^",
     "@backstage/backend-test-utils": "workspace:^",
     "@backstage/cli": "workspace:^",
+    "@backstage/plugin-permission-backend": "workspace:^",
+    "@backstage/plugin-permission-backend-module-allow-all-policy": "workspace:^",
     "@types/aws4": "^1.5.1",
     "msw": "^1.0.0",
     "supertest": "^6.1.3",

plugins/kubernetes-backend/src/plugin.ts

@@ -32,6 +32,11 @@ import {
   KubernetesAuthStrategyExtensionPoint,
   AuthenticationStrategy,
   kubernetesAuthStrategyExtensionPoint,
+  KubernetesFetcher,
+} from '@backstage/plugin-kubernetes-node';
+import {
+  KubernetesFetcherExtensionPoint,
+  kubernetesFetcherExtensionPoint,
 } from '@backstage/plugin-kubernetes-node';
 
 class ObjectsProvider implements KubernetesObjectsProviderExtensionPoint {
@@ -68,6 +73,23 @@ class ClusterSuplier implements KubernetesClusterSupplierExtensionPoint {
   }
 }
 
+class Fetcher implements KubernetesFetcherExtensionPoint {
+  private fetcher: KubernetesFetcher | undefined;
+
+  getFetcher() {
+    return this.fetcher;
+  }
+
+  addFetcher(fetcher: KubernetesFetcher) {
+    if (this.fetcher) {
+      throw new Error(
+        'Multiple Kubernetes Fetchers is not supported at this time',
+      );
+    }
+    this.fetcher = fetcher;
+  }
+}
+
 class AuthStrategy implements KubernetesAuthStrategyExtensionPoint {
   private authStrategies: Array<{
     key: string;
@@ -108,6 +130,7 @@ export const kubernetesPlugin = createBackendPlugin({
     const extPointObjectsProvider = new ObjectsProvider();
     const extPointClusterSuplier = new ClusterSuplier();
     const extPointAuthStrategy = new AuthStrategy();
+    const extPointFetcher = new Fetcher();
     env.registerExtensionPoint(
       kubernetesObjectsProviderExtensionPoint,
       extPointObjectsProvider,
@@ -120,6 +143,10 @@ export const kubernetesPlugin = createBackendPlugin({
       kubernetesAuthStrategyExtensionPoint,
       extPointAuthStrategy,
     );
+    env.registerExtensionPoint(
+      kubernetesFetcherExtensionPoint,
+      extPointFetcher,
+    );
 
     env.registerInit({
       deps: {
@@ -139,7 +166,8 @@ export const kubernetesPlugin = createBackendPlugin({
           permissions,
         })
           .setObjectsProvider(extPointObjectsProvider.getObjectsProvider())
-          .setClusterSupplier(extPointClusterSuplier.getClusterSupplier());
+          .setClusterSupplier(extPointClusterSuplier.getClusterSupplier())
+          .setFetcher(extPointFetcher.getFetcher());
         AuthStrategy.addAuthStrategiesFromArray(
           extPointAuthStrategy.getAuthenticationStrategies(),
           builder,

plugins/kubernetes-backend/src/types/types.ts

@@ -18,75 +18,16 @@ import { Entity } from '@backstage/catalog-model';
 import { Logger } from 'winston';
 import type {
   CustomResourceMatcher,
-  FetchResponse,
-  KubernetesFetchError,
   KubernetesRequestBody,
 } from '@backstage/plugin-kubernetes-common';
 import { Config } from '@backstage/config';
 import {
   ClusterDetails,
-  KubernetesCredential,
+  CustomResource,
+  KubernetesFetcher,
+  ObjectToFetch,
 } from '@backstage/plugin-kubernetes-node';
 
-/**
- *
- * @public
- */
-export interface ObjectFetchParams {
-  serviceId: string;
-  clusterDetails: ClusterDetails;
-  credential: KubernetesCredential;
-  objectTypesToFetch: Set<ObjectToFetch>;
-  labelSelector?: string;
-  customResources: CustomResource[];
-  namespace?: string;
-}
-
-/**
- * Fetches information from a kubernetes cluster using the cluster details object to target a specific cluster
- *
- * @public
- */
-export interface KubernetesFetcher {
-  fetchObjectsForService(
-    params: ObjectFetchParams,
-  ): Promise<FetchResponseWrapper>;
-  fetchPodMetricsByNamespaces(
-    clusterDetails: ClusterDetails,
-    credential: KubernetesCredential,
-    namespaces: Set<string>,
-    labelSelector?: string,
-  ): Promise<FetchResponseWrapper>;
-}
-
-/**
- *
- * @public
- */
-export interface FetchResponseWrapper {
-  errors: KubernetesFetchError[];
-  responses: FetchResponse[];
-}
-
-/**
- *
- * @public
- */
-export interface ObjectToFetch {
-  objectType: KubernetesObjectTypes;
-  group: string;
-  apiVersion: string;
-  plural: string;
-}
-
-/**
- *
- * @public
- */
-export interface CustomResource extends ObjectToFetch {
-  objectType: 'customresources';
-}
-
 /**
  *
  * @public
@@ -157,4 +98,9 @@ export type {
   AuthMetadata,
   ClusterDetails,
   KubernetesClustersSupplier,
+  ObjectToFetch,
+  CustomResource,
+  ObjectFetchParams,
+  FetchResponseWrapper,
+  KubernetesFetcher,
 } from '@backstage/plugin-kubernetes-node';

plugins/kubernetes-node/package.json

@@ -30,6 +30,7 @@
   "dependencies": {
     "@backstage/backend-plugin-api": "workspace:^",
     "@backstage/catalog-model": "workspace:^",
+    "@backstage/plugin-kubernetes-backend": "workspace:^",
     "@backstage/plugin-kubernetes-common": "workspace:^",
     "@backstage/types": "workspace:^"
   }

plugins/kubernetes-node/src/extensions.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 import { createExtensionPoint } from '@backstage/backend-plugin-api';
+import { KubernetesFetcher } from '@backstage/plugin-kubernetes-backend';
 import { AuthenticationStrategy } from '@backstage/plugin-kubernetes-node';
 import { KubernetesClustersSupplier } from '@backstage/plugin-kubernetes-node';
 import { KubernetesObjectsProvider } from '@backstage/plugin-kubernetes-node';
@@ -74,3 +75,22 @@ export const kubernetesAuthStrategyExtensionPoint =
   createExtensionPoint<KubernetesAuthStrategyExtensionPoint>({
     id: 'kubernetes.auth-strategy',
   });
+
+/**
+ * The interface for {@link kubernetesFetcherExtensionPoint}.
+ *
+ * @public
+ */
+export interface KubernetesFetcherExtensionPoint {
+  addFetcher(fetcher: KubernetesFetcher): void;
+}
+
+/**
+ * An extension point the exposes the ability to configure a kubernetes fetcher.
+ *
+ * @public
+ */
+export const kubernetesFetcherExtensionPoint =
+  createExtensionPoint<KubernetesFetcherExtensionPoint>({
+    id: 'kubernetes.fetcher',
+  });

plugins/kubernetes-node/src/index.ts

@@ -29,13 +29,5 @@
  * @packageDocumentation
  */
 
-export {
-  kubernetesObjectsProviderExtensionPoint,
-  type KubernetesObjectsProviderExtensionPoint,
-  kubernetesClusterSupplierExtensionPoint,
-  type KubernetesClusterSupplierExtensionPoint,
-  kubernetesAuthStrategyExtensionPoint,
-  type KubernetesAuthStrategyExtensionPoint,
-} from './extensions';
-
+export * from './extensions';
 export * from './types';

plugins/kubernetes-node/src/types/types.ts

@@ -14,8 +14,11 @@
  * limitations under the License.
  */
 import { Entity } from '@backstage/catalog-model';
+import { KubernetesObjectTypes } from '@backstage/plugin-kubernetes-backend';
 import {
   CustomResourceMatcher,
+  FetchResponse,
+  KubernetesFetchError,
   KubernetesRequestAuth,
   ObjectsByEntityResponse,
 } from '@backstage/plugin-kubernetes-common';
@@ -150,3 +153,62 @@ export interface AuthenticationStrategy {
   ): Promise<KubernetesCredential>;
   validateCluster(authMetadata: AuthMetadata): Error[];
 }
+
+/**
+ *
+ * @public
+ */
+export interface ObjectToFetch {
+  objectType: KubernetesObjectTypes; // TODO - Review
+  group: string;
+  apiVersion: string;
+  plural: string;
+}
+
+/**
+ *
+ * @public
+ */
+export interface CustomResource extends ObjectToFetch {
+  objectType: 'customresources';
+}
+
+/**
+ *
+ * @public
+ */
+export interface ObjectFetchParams {
+  serviceId: string;
+  clusterDetails: ClusterDetails;
+  credential: KubernetesCredential;
+  objectTypesToFetch: Set<ObjectToFetch>;
+  labelSelector?: string;
+  customResources: CustomResource[];
+  namespace?: string;
+}
+
+/**
+ *
+ * @public
+ */
+export interface FetchResponseWrapper {
+  errors: KubernetesFetchError[];
+  responses: FetchResponse[];
+}
+
+/**
+ * Fetches information from a kubernetes cluster using the cluster details object to target a specific cluster
+ *
+ * @public
+ */
+export interface KubernetesFetcher {
+  fetchObjectsForService(
+    params: ObjectFetchParams,
+  ): Promise<FetchResponseWrapper>;
+  fetchPodMetricsByNamespaces(
+    clusterDetails: ClusterDetails,
+    credential: KubernetesCredential,
+    namespaces: Set<string>,
+    labelSelector?: string,
+  ): Promise<FetchResponseWrapper>;
+}