Do not force using all GitHub variables with --github mode

README.md

@@ -223,6 +223,7 @@ Read more about personal tokens [here](https://docs.github.com/en/authentication
 * Set `--github` flag - Bazel Steward now only works with GitHub as a platform. Without the flag, it will only push the branches, but is not able to check PR status or open/close them.
   * Set `GITHUB_TOKEN` env - necessary for PR management
   * Set `GITHUB_REPOSITORY` env to your repository location. Example value: `VirtusLab/bazel-steward` 
+  * Optionally set `GITHUB_API_URL` if you are not using the public GitHub. Default is `https://api.github.com`
 
 ### Command line arguments
 ```

app/src/main/kotlin/org/virtuslab/bazelsteward/app/AppBuilder.kt

@@ -63,7 +63,7 @@ object AppBuilder {
 
     parser.parse(args)
 
-    val repositoryRoot = if (github) GithubClient.getRepoPath(env) else Path(repository)
+    val repositoryRoot = Path(repository).let { if (github) GithubClient.getRepoPath(env, it) else it }
     val gitClient = GitClient(repositoryRoot)
     val baseBranchName = baseBranch ?: runBlocking {
       gitClient.run("rev-parse", "--abbrev-ref", "HEAD").trim()
@@ -86,16 +86,24 @@ object AppBuilder {
     val mavenRepository = MavenRepository()
     val updateLogic = UpdateLogic()
     val gitOperations = GitOperations(appConfig.workspaceRoot, appConfig.baseBranch)
-    val gitHostClient =
-      if (github) GithubClient.getClient(env, appConfig.baseBranch, appConfig.gitAuthor) else GitHostClient.stub
+    val gitHostClient = if (github) {
+      GithubClient.getClient(env, appConfig.baseBranch, appConfig.gitAuthor)
+    } else {
+      logger.warn {
+        """Using stub client for git host. Pull Request management will not work correctly.
+        |Use --github flag to enable GitHub support. Other Platforms are not supported yet.
+        """.trimMargin()
+      }
+      GitHostClient.stub
+    }
     val bazelRulesExtractor = BazelRulesExtractor()
     val bazelUpdater = BazelUpdater()
-    val gitHubClient = (
+    val githubApi = (
       env["GITHUB_TOKEN"]
         ?.let(GitHub::connectUsingOAuth)
         ?: GitHub.connectAnonymously()
       )
-    val githubRulesResolver = GithubRulesResolver(gitHubClient)
+    val githubRulesResolver = GithubRulesResolver(githubApi)
     val fileFinder = FileFinder(appConfig.workspaceRoot)
 
     val dependencyKinds = listOf(

github/src/main/kotlin/org/virtuslab/bazelsteward/github/GithubClient.kt

@@ -104,16 +104,15 @@ class GithubClient private constructor(
 
   companion object {
     fun getClient(env: Environment, baseBranch: String, gitAuthor: GitClient.GitAuthor): GithubClient {
-      val url = env.getOrThrow("GITHUB_API_URL")
+      val url = env.getOrDefault("GITHUB_API_URL", "https://api.github.com")
       val repository = env.getOrThrow("GITHUB_REPOSITORY")
       val token = env.getOrThrow("GITHUB_TOKEN")
       val personalToken = env["PERSONAL_TOKEN"].let { if (it.isNullOrBlank()) null else it }
       return GithubClient(url, baseBranch, gitAuthor, repository, token, personalToken)
     }
 
-    fun getRepoPath(env: Environment): Path {
-      val workspace = env.getOrThrow("GITHUB_WORKSPACE")
-      return Path(workspace)
+    fun getRepoPath(env: Environment, fallback: Path): Path {
+      return env["GITHUB_WORKSPACE"]?.let { Path(it) } ?: fallback
     }
   }
 }