Allow the entities indexed by DefaultCatalogCollator to be filtered by kind

Signed-off-by: Roy Jacobs <roy.jacobs@gmail.com>

.changeset/happy-cups-tap.md

@@ -0,0 +1,6 @@
+---
+'example-backend': patch
+'@backstage/plugin-catalog-backend': patch
+---
+
+Allow the catalog search collator to filter the entities that it indexes

packages/backend/src/plugins/search.ts

@@ -68,7 +68,7 @@ export default async function createPlugin({
   // particular collator gathers entities from the software catalog.
   indexBuilder.addCollator({
     defaultRefreshIntervalSeconds: 600,
-    collator: new DefaultCatalogCollator({ discovery }),
+    collator: DefaultCatalogCollator.fromConfig(config, { discovery }),
   });
 
   indexBuilder.addCollator({

plugins/catalog-backend/api-report.md

@@ -581,9 +581,11 @@ export class DefaultCatalogCollator implements DocumentCollator {
   constructor({
     discovery,
     locationTemplate,
+    allow,
   }: {
     discovery: PluginEndpointDiscovery;
     locationTemplate?: string;
+    allow?: string[];
   });
   // (undocumented)
   protected applyArgsToFormat(
@@ -595,6 +597,15 @@ export class DefaultCatalogCollator implements DocumentCollator {
   // (undocumented)
   execute(): Promise<CatalogEntityDocument[]>;
   // (undocumented)
+  protected filterUrl: string;
+  // (undocumented)
+  static fromConfig(
+    config: Config,
+    options: {
+      discovery: PluginEndpointDiscovery;
+    },
+  ): DefaultCatalogCollator;
+  // (undocumented)
   protected locationTemplate: string;
   // (undocumented)
   readonly type: string;

plugins/catalog-backend/config.d.ts

@@ -179,5 +179,17 @@ export interface Config {
         };
       };
     };
+
+    /**
+     * Configuration for search collation
+     */
+    search?: {
+      /**
+       * Request search to only index these particular kinds.
+       *
+       * E.g. ["Component", "API", "Template", "Location"]
+       */
+      allow: Array<string>;
+    };
   };
 }

plugins/catalog-backend/src/search/DefaultCatalogCollator.test.ts

@@ -17,6 +17,11 @@
 import { PluginEndpointDiscovery } from '@backstage/backend-common';
 import { Entity } from '@backstage/catalog-model';
 import { DefaultCatalogCollator } from './DefaultCatalogCollator';
+import { setupServer } from 'msw/node';
+import { rest } from 'msw';
+import { ConfigReader } from '@backstage/config';
+
+const server = setupServer();
 
 const expectedEntities: Entity[] = [
   {
@@ -34,27 +39,37 @@ const expectedEntities: Entity[] = [
   },
 ];
 
-jest.mock('cross-fetch', () => ({
-  __esModule: true,
-  default: async () => {
-    return {
-      json: async () => {
-        return expectedEntities;
-      },
-    };
-  },
-}));
-
 describe('DefaultCatalogCollator', () => {
   let mockDiscoveryApi: jest.Mocked<PluginEndpointDiscovery>;
   let collator: DefaultCatalogCollator;
 
-  beforeEach(() => {
+  beforeAll(() => {
     mockDiscoveryApi = {
-      getBaseUrl: jest.fn().mockResolvedValueOnce('http://localhost:7000'),
+      getBaseUrl: jest.fn().mockResolvedValue('http://localhost:7000'),
       getExternalBaseUrl: jest.fn(),
     };
     collator = new DefaultCatalogCollator({ discovery: mockDiscoveryApi });
+    server.listen();
+  });
+  beforeEach(() => {
+    server.use(
+      rest.get('http://localhost:7000/entities', (req, res, ctx) => {
+        if (req.url.searchParams.has('filter')) {
+          const filter = req.url.searchParams.get('filter');
+          if (filter === 'kind=Foo,Bar') {
+            // When filtering on the 'Foo,Bar' kinds we simply return no items, to simulate a filter
+            return res(ctx.json([]));
+          }
+          throw new Error('Unexpected filter parameter');
+        }
+        return res(ctx.json(expectedEntities));
+      }),
+    );
+  });
+  afterEach(() => server.resetHandlers());
+  afterAll(() => {
+    server.close();
+    jest.useRealTimers();
   });
 
   it('fetches from the configured catalog service', async () => {
@@ -88,4 +103,23 @@ describe('DefaultCatalogCollator', () => {
       location: '/software/test-entity',
     });
   });
+
+  it('allows filtering of the retrieved catalog entities', async () => {
+    const config = new ConfigReader({
+      catalog: {
+        search: {
+          allow: ['Foo', 'Bar'],
+        },
+      },
+    });
+
+    // Provide an alternate location template.
+    collator = DefaultCatalogCollator.fromConfig(config, {
+      discovery: mockDiscoveryApi,
+    });
+
+    const documents = await collator.execute();
+    // The simulated 'Foo,Bar' filter should return in an empty list
+    expect(documents).toHaveLength(0);
+  });
 });

plugins/catalog-backend/src/search/DefaultCatalogCollator.ts

@@ -18,6 +18,7 @@ import { PluginEndpointDiscovery } from '@backstage/backend-common';
 import { Entity } from '@backstage/catalog-model';
 import { IndexableDocument, DocumentCollator } from '@backstage/search-common';
 import fetch from 'cross-fetch';
+import { Config } from '@backstage/config';
 
 export interface CatalogEntityDocument extends IndexableDocument {
   componentType: string;
@@ -30,18 +31,36 @@ export interface CatalogEntityDocument extends IndexableDocument {
 export class DefaultCatalogCollator implements DocumentCollator {
   protected discovery: PluginEndpointDiscovery;
   protected locationTemplate: string;
+  protected filterUrl: string;
   public readonly type: string = 'software-catalog';
 
+  static fromConfig(
+    config: Config,
+    options: { discovery: PluginEndpointDiscovery },
+  ) {
+    return new DefaultCatalogCollator({
+      ...options,
+      allow: config.getOptionalStringArray('catalog.search.allow'),
+    });
+  }
+
   constructor({
     discovery,
     locationTemplate,
+    allow,
   }: {
     discovery: PluginEndpointDiscovery;
     locationTemplate?: string;
+    allow?: string[];
   }) {
     this.discovery = discovery;
     this.locationTemplate =
       locationTemplate || '/catalog/:namespace/:kind/:name';
+    if (allow && allow.length) {
+      this.filterUrl = `?filter=kind=${allow.join(',')}`;
+    } else {
+      this.filterUrl = '';
+    }
   }
 
   protected applyArgsToFormat(
@@ -57,7 +76,7 @@ export class DefaultCatalogCollator implements DocumentCollator {
 
   async execute() {
     const baseUrl = await this.discovery.getBaseUrl('catalog');
-    const res = await fetch(`${baseUrl}/entities`);
+    const res = await fetch(`${baseUrl}/entities${this.filterUrl}`);
     const entities: Entity[] = await res.json();
     return entities.map((entity: Entity): CatalogEntityDocument => {
       return {