Gerrit: Make the gitilesBaseUrl mandatory

This patch makes the Gerrit UrlReader throw an exception if the
gitilesBaseUrl is not set. This can be opt out of by setting the
env variable DISABLE_GERRIT_GITILES_REQUIREMENT.

Signed-off-by: Niklas Aronsson <niklasar@axis.com>

.changeset/cyan-ducks-sin.md

@@ -0,0 +1,8 @@
+---
+'@backstage/backend-common': minor
+---
+
+**BREAKING**: `A gitilesBaseUrl` must be provided for the Gerrit integration to work.
+You can disable this check by setting `DISABLE_GERRIT_GITILES_REQUIREMENT=1` but
+this will be removed in a future release. If you are not able to use the Gitiles
+Gerrit plugin, please open an issue towards `https://github.com/backstage/backstage`

packages/backend-common/src/reading/GerritUrlReader.test.ts

@@ -32,10 +32,15 @@ import path from 'path';
 import { getVoidLogger } from '../logging';
 import { UrlReaderPredicateTuple } from './types';
 import { DefaultReadTreeResponseFactory } from './tree';
-import { GerritUrlReader } from './GerritUrlReader';
+import {
+  GITILES_BASE_URL_DEPRECATION_MESSSAGE,
+  GerritUrlReader,
+} from './GerritUrlReader';
 import getRawBody from 'raw-body';
 
 const mockDir = createMockDirectory({ mockOsTmpDir: true });
+const env = process.env;
+process.env = { ...env, DISABLE_GERRIT_GITILES_REQUIREMENT: '1' };
 
 const treeResponseFactory = DefaultReadTreeResponseFactory.create({
   config: new ConfigReader({}),
@@ -93,10 +98,14 @@ describe.skip('GerritUrlReader', () => {
   const worker = setupServer();
   setupRequestMockHandlers(worker);
 
-  beforeEach(mockDir.clear);
+  beforeEach(() => {
+    mockDir.clear();
+    process.env = { ...env, DISABLE_GERRIT_GITILES_REQUIREMENT: '1' };
+  });
 
   afterAll(() => {
     jest.clearAllMocks();
+    process.env = env;
   });
 
   describe('reader factory', () => {
@@ -117,6 +126,29 @@ describe.skip('GerritUrlReader', () => {
     });
   });
 
+  describe('handle optional gitilesBaseUrl deprecation', () => {
+    it('should throw if gitilesBaseUrl is not set.', () => {
+      process.env = env;
+      expect(() =>
+        createReader({
+          integrations: {
+            gerrit: [{ host: 'gerrit.com' }],
+          },
+        }),
+      ).toThrow(GITILES_BASE_URL_DEPRECATION_MESSSAGE);
+    });
+    it('should not throw if gitilesBaseUrl requirement is overridden.', () => {
+      process.env = { ...env, DISABLE_GERRIT_GITILES_REQUIREMENT: '1' };
+      expect(() =>
+        createReader({
+          integrations: {
+            gerrit: [{ host: 'gerrit.com' }],
+          },
+        }),
+      ).not.toThrow();
+    });
+  });
+
   describe('predicates without Gitiles', () => {
     const readers = createReader({
       integrations: {

packages/backend-common/src/reading/GerritUrlReader.ts

@@ -49,6 +49,12 @@ import {
 
 const pipeline = promisify(pipelineCb);
 
+export const GITILES_BASE_URL_DEPRECATION_MESSSAGE = `A gitilesBaseUrl must be provided \
+for the gerrit integration to work. You can disable this check by setting \
+DISABLE_GERRIT_GITILES_REQUIREMENT=1 but this will be removed in a future release. If you \
+are not able to use the gitiles gerrit plugin, please open an issue towards \
+https://github.com/backstage/backstage`;
+
 const createTemporaryDirectory = async (workDir: string): Promise<string> =>
   await fs.mkdtemp(joinPath(workDir, '/gerrit-clone-'));
 
@@ -81,6 +87,12 @@ export class GerritUrlReader implements UrlReader {
     const workDir =
       config.getOptionalString('backend.workingDirectory') ?? os.tmpdir();
     return integrations.gerrit.list().map(integration => {
+      if (
+        integration.config.gitilesBaseUrl === integration.config.baseUrl &&
+        process.env.DISABLE_GERRIT_GITILES_REQUIREMENT === undefined
+      ) {
+        throw new Error(GITILES_BASE_URL_DEPRECATION_MESSSAGE);
+      }
       const reader = new GerritUrlReader(
         integration,
         { treeResponseFactory },