Merge pull request #10428 from spreadshirt/kubernetes-cluster-refresh

Make Kubernetes clusters refreshable
2022-04-11 14:21:15 +02:00
parent ede6adf31d 2fc0e86616
commit 8bda364ece
13 changed files with 347 additions and 94 deletions
@@ -57,6 +57,10 @@ This is an array used to determine where to retrieve cluster configuration from.

 Valid cluster locator methods are:

+- [`config`](#config)
+- [`gke`](#gke)
+- [custom `KubernetesClustersSupplier`](#custom-kubernetesclusterssupplier)
+
 #### `config`

 This cluster locator method will read cluster information from your app-config
@@ -261,6 +265,12 @@ Kubernetes plugin.

 Defaults to `false`.

+#### Custom `KubernetesClustersSupplier`
+
+If the configuration-based cluster locators do not work for your use-case,
+it is also possible to implement a
+[custom `KubernetesClustersSupplier`](installation.md#custom-cluster-discovery).
+
 ### `customResources` (optional)

 Configures which [custom resources][3] to look for when returning an entity's
@@ -90,6 +90,63 @@ async function main() {
 That's it! The Kubernetes frontend and backend have now been added to your
 Backstage app.

+### Custom cluster discovery
+
+If either existing
+[cluster locators](https://backstage.io/docs/features/kubernetes/configuration#clusterlocatormethods)
+don't work for your use-case, it is possible to implement a custom
+[KubernetesClustersSupplier](https://backstage.io/docs/reference/plugin-kubernetes-backend.kubernetesclusterssupplier).
+
+Change the following in `packages/backend/src/plugin/kubernetes.ts`:
+
+```diff
+-import { KubernetesBuilder } from '@backstage/plugin-kubernetes-backend';
+import {
+  ClusterDetails,
+  KubernetesBuilder,
+  KubernetesClustersSupplier,
+} from '@backstage/plugin-kubernetes-backend';
+ import { Router } from 'express';
+ import { PluginEnvironment } from '../types';
+import { Duration } from 'luxon';
+
+export class CustomClustersSupplier implements KubernetesClustersSupplier {
+  constructor(private clusterDetails: ClusterDetails[] = []) {}
+
+  static create(refreshInterval: Duration) {
+    const clusterSupplier = new CustomClustersSupplier();
+    // setup refresh, e.g. using a copy of https://github.com/backstage/backstage/blob/master/plugins/search-backend-node/src/runPeriodically.ts
+    runPeriodically(
+      () => clusterSupplier.refreshClusters(),
+      refreshInterval.toMillis(),
+    );
+    return clusterSupplier;
+  }
+
+  async refreshClusters(): Promise<void> {
+    this.clusterDetails = []; // fetch from somewhere
+  }
+
+  async getClusters(): Promise<ClusterDetails[]> {
+    return this.clusterDetails;
+  }
+}
+
+ export default async function createPlugin(
+   env: PluginEnvironment,
+ ): Promise<Router> {
+-  const { router } = await KubernetesBuilder.createBuilder({
+  const builder = await KubernetesBuilder.createBuilder({
+     logger: env.logger,
+     config: env.config,
+-  }).build();
+  });
+  builder.setClusterSupplier(
+    CustomClustersSupplier.create(Duration.fromObject({ minutes: 60 })),
+  );
+  const { router } = await builder.build();
+```
+
 ## Running Backstage locally

 Start the frontend and the backend app by