TechDocs Backend: Replace hardcoded github api by configuration value (#3004)

* replace hardcoded  by configuration value

* use integrations configuration to read github apiBaseUrl

Co-authored-by: Emre Konar <emre.konar@zalando.de>

.changeset/pink-spies-rule.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs-backend': patch
+---
+
+Replacing the hard coded `baseApiUrl` by reading the value from configuration to enable private GitHub setup for TechDocs.

plugins/techdocs-backend/src/default-branch.ts

@@ -42,9 +42,11 @@ interface IGitlabBranch {
   };
 }
 
-function getGithubApiUrl(url: string): URL {
+function getGithubApiUrl(config: Config, url: string): URL {
   const { protocol, owner, name } = parseGitUrl(url);
-  const apiBaseUrl = 'api.github.com';
+  const apiBaseUrl =
+    config.getOptionalString('integrations.github.apiBaseUrl') ||
+    'api.github.com';
   const apiRepos = 'repos';
 
   return new URL(`${protocol}://${apiBaseUrl}/${apiRepos}/${owner}/${name}`);
@@ -133,7 +135,7 @@ async function getGithubDefaultBranch(
   repositoryUrl: string,
   config: Config,
 ): Promise<string> {
-  const path = getGithubApiUrl(repositoryUrl).toString();
+  const path = getGithubApiUrl(config, repositoryUrl).toString();
   const options = getGithubRequestOptions(config);
 
   try {