Gerrit Lightweight Checkout

Fetch a Pipeline's Jenkinsfile through the Gerrit REST API instead of fetching the Git repository on the Jenkins controller. This plugin adds an optional Git SCM behavior for Pipeline script from SCM jobs with Lightweight checkout enabled.

1. Install the plugin and its Git, SCM API, and Credentials dependencies.
2. In a Pipeline job, choose Pipeline script from SCM, then Git. Configure the repository URL and Git credentials as usual.
3. Configure exactly one remote and one branch. Supported values include */main, refs/heads/feature/topic, a full 40-character commit SHA, and Gerrit patch-set refs such as refs/changes/34/1234/5. You can also use variables that are provided by a plugin the gives this information (e.g., the Gerrit Trigger Plugin).
4. Under Additional Behaviours, add Gerrit REST lightweight checkout.
5. Enter the Gerrit web URL (for example https://review.example.com/gerrit) and exact project name (for example team/service). The project must match the Git repository. Do not include /a in the URL or URL-encode the project.
6. Select an optional username/password credential containing your Gerrit username and HTTP password/token. REST credentials are separate from Git SSH credentials. Leave this empty for anonymous access.
7. Set Script Path to Jenkinsfile or a nested path such as ci/Jenkinsfile, and enable Lightweight checkout.

The Jenkins controller needs HTTP(S) access to Gerrit. Authenticated requests use Gerrit's /a prefix and HTTP Basic authentication; use HTTPS for authenticated servers. Jenkins proxy configuration is honored. Redirects are rejected, so configure the final Gerrit URL.

The plugin first resolves the configured branch or patch set to a commit, then reads the script from that commit's file-content endpoint and decodes Gerrit's base64 response. Reading the script does not require Git or a controller-side repository cache. Git still handles workspace checkout, polling, and changelogs; a subsequent checkout scm can observe a newer branch tip.

Build environment variables in branch specifications are expanded when Jenkins supplies a build context, including a Gerrit-triggered job configured with ${GERRIT_REFSPEC}. Unresolved variables, wildcard branch selection, multiple remotes/branches, and tag refs are unsupported. This integration targets ordinary Pipeline-from-SCM jobs, not multibranch discovery or a Gerrit SCMSource. Directory listing and REST-based changelogs are unsupported.

The REST provider takes priority over Git's built-in lightweight provider for jobs with this behavior. Jenkins' SCM API can try another provider if REST filesystem initialization fails, so a REST connection or configuration failure may cause Git's lightweight provider to fetch a repository. Failures reading a file after REST initialization (including missing files or authorization failures) are reported as errors.

Requests use 30-second connect/read timeouts and an 8 MiB limit per response. Missing resources return file-not-found errors; authentication and server failures preserve the HTTP status without printing response bodies or credentials.

mvn verify

Install target/gerrit-lightweight-checkout.hpi through Jenkins' advanced plugin installation page. For development, use mvn hpi:run.

Tests include a real Pipeline-from-SCM build against a local Gerrit HTTP fixture with an unreachable Git remote, authenticated credential lookup, nested script paths, patch-set resolution, error handling, and configuration persistence.

The implementation follows the Jenkins SCM API, Gerrit's project REST endpoints, and its REST authentication conventions.

MIT