feat(platform/github): autodiscover repos by topic

docs/usage/self-hosted-configuration.md

@@ -130,6 +130,14 @@ If using negations, all repositories except those who match the regex are added
 Some platforms allow you to add tags, or topics, to repositories and retrieve repository lists by specifying those
 topics. Set this variable to a list of strings, all of which will be topics for the autodiscovered repositories.
 
+For example:
+
+```json
+{
+  "autodiscoverTopics": ["managed-by-renovate"]
+}
+```
+
 ## baseDir
 
 By default Renovate uses a temporary directory like `/tmp/renovate` to store its data.

lib/config/options/index.ts

@@ -800,13 +800,13 @@ const options: RenovateOptions[] = [
   },
   {
     name: 'autodiscoverTopics',
-    description: '',
+    description: 'Filter the list of autodiscovered repositories by topics.',
     stage: 'global',
     type: 'array',
     subType: 'string',
     default: null,
     globalOnly: true,
-    supportedPlatforms: ['gitlab'],
+    supportedPlatforms: ['github', 'gitlab'],
   },
   {
     name: 'prCommitsPerRunLimit',

lib/modules/platform/github/index.spec.ts

@@ -192,6 +192,33 @@ describe('modules/platform/github/index', () => {
       expect(repos).toMatchSnapshot();
     });
 
+    it('should filters repositories by topics', async () => {
+      httpMock
+        .scope(githubApiHost)
+        .get('/user/repos?per_page=100')
+        .reply(200, [
+          {
+            full_name: 'a/b',
+            archived: false,
+            topics: [],
+          },
+          {
+            full_name: 'c/d',
+            archived: false,
+            topics: ['managed-by-renovate'],
+          },
+          {
+            full_name: 'e/f',
+            archived: true,
+            topics: ['managed-by-renovate'],
+          },
+          null,
+        ]);
+
+      const repos = await github.getRepos({ topics: ['managed-by-renovate'] });
+      expect(repos).toEqual(['c/d']);
+    });
+
     it('should return an array of repos when using Github App endpoint', async () => {
       //Use Github App token
       await github.initPlatform({

lib/modules/platform/github/index.ts

@@ -42,6 +42,7 @@ import { fromBase64, looseEquals } from '../../../util/string';
 import { ensureTrailingSlash } from '../../../util/url';
 import type {
   AggregatedVulnerabilities,
+  AutodiscoverConfig,
   BranchStatusConfig,
   CreatePRConfig,
   EnsureCommentConfig,
@@ -187,9 +188,7 @@ export async function initPlatform({
   return platformResult;
 }
 
-// Get all repositories that the user has access to
-export async function getRepos(): Promise<string[]> {
-  logger.debug('Autodiscovering GitHub repositories');
+async function fetchRepositories(): Promise<GhRestRepo[]> {
   try {
     if (platformConfig.isGHApp) {
       const res = await githubApi.getJson<{
@@ -198,26 +197,36 @@ export async function getRepos(): Promise<string[]> {
         paginationField: 'repositories',
         paginate: 'all',
       });
-      return res.body.repositories
-        .filter(is.nonEmptyObject)
-        .filter((repo) => !repo.archived)
-        .map((repo) => repo.full_name);
+      return res.body.repositories;
     } else {
       const res = await githubApi.getJson<GhRestRepo[]>(
         `user/repos?per_page=100`,
         { paginate: 'all' }
       );
-      return res.body
-        .filter(is.nonEmptyObject)
-        .filter((repo) => !repo.archived)
-        .map((repo) => repo.full_name);
+      return res.body;
     }
   } catch (err) /* istanbul ignore next */ {
     logger.error({ err }, `GitHub getRepos error`);
     throw err;
   }
 }
 
+// Get all repositories that the user has access to
+export async function getRepos(config?: AutodiscoverConfig): Promise<string[]> {
+  logger.debug('Autodiscovering GitHub repositories');
+  return (await fetchRepositories())
+    .filter(is.nonEmptyObject)
+    .filter((repo) => !repo.archived)
+    .filter((repo) => {
+      if (config?.topics) {
+        const autodiscoverTopics = config.topics;
+        return repo.topics.some((topic) => autodiscoverTopics.includes(topic));
+      }
+      return true;
+    })
+    .map((repo) => repo.full_name);
+}
+
 async function getBranchProtection(
   branchName: string
 ): Promise<BranchProtection> {

lib/modules/platform/github/types.ts

@@ -27,6 +27,7 @@ export interface GhRestRepo {
     login: string;
   };
   archived: boolean;
+  topics: string[];
 }
 
 export interface GhRestPr {