GitHub plugin

This plugin allows existing GitHub repositories to be integrated as Gerrit projects.

Why using GitHub and Gerrit together ?

Many people see Gerrit and GitHub as opposites: the pull-request model adopted by GitHub is often used as “easy shortcut” to the more comprehensive and structured code-review process in Gerrit.

There are many discussion threads on this:

In reality there are already OpenSource projects that have started using the two tools together:

The reason for using GitHub and Gerrit together are: a) GitHub is widely recognised and accessible by lots of world-wide sites. b) Using a public GitHub repo allows to “off-load” a lot of git pull traffic. c) Pull-request allows novice users to start getting involved. d) Gerrit code-review define the quality gates for avoiding “noise” of unstructured contributions.

Why a Gerrit plugin ?

When using GitHub and Gerrit together, the “master of truth” has to be Gerrit: this is because it is the place where more control in terms of security and workflow can be defined.

A Gerrit plugin can help controlling the GitHub replica and importing the pull requests as Gerrit changes.

Integration points

Authentication. (DONE - Change-Id: I7291a90014e51316af3cb07fd03785c1ef33acd0)

Users can login to Gerrit using the same username and credentials in GitHub. Gerrit login points to GitHub for generating the OAuth token to be used for the code-review authenticated session.

The initial Gerrit registration page can be customised to import GitHub SSH Keys directly into Gerrit.

Push-Pull replication. (WIP - Change-Id: I596b2e80b4d9519668a1ab289d6c950139d6a922)

Existing GitHub repositories are automatically replicated to Gerrit for the purpose of performing code-review and pushing back changes once approved. Additionally to the standard Gerrit push replication, supports as well the ability to pull branches from remote GitHub repositories.

Pull-request to Change. (DONE - Change-Id: d669e351a03798cc2ec966d028458f083c232564)

Hooks into the GitHub pull-request mechanism to automatically create a Change in Gerrit submitted for review.

How to build this plugin

Gerrit 2.8 build

GitHub plugin is designed to work with Gerrit 2.8 (currently in development). In order to build the GitHub plugin you need to have a working Gerrit 2.8 build in place.

See https://gerrit-review.googlesource.com/Documentation/dev-buck.html for a reference on how to build Gerrit 2.8 (master branch) using BUCK.

GitHub API

In order to access GitHub API, we have used the lucamilanesio fork of Kohsuke API layer hosted on GitHub at https://github.com/lucamilanesio/github-api.

You need to clone and build the GitHub API as pre-requisite for building the GitHub plugin for Gerrit.

Example: git clone https://github.com/lucamilanesio/github-api.git cd github-api mvn install

singleusergroup plugin

You need to clone, build and install the singleusergroup plugin for Gerrit (see https://gerrit-review.googlesource.com/#/admin/projects/plugins/singleusergroup).

This plugin is needed to allow Gerrit to use individual users as Groups for being used in Gerrit ACLs.

Example: git clone https://gerrit.googlesource.com/plugins/singleusergroup cd singleusergroup mvn install cp target/singleusergroup-*.jar $GERRIT_SITE/plugins/.

Building GitHub integration for Gerrit

Just clone the Git repository (see https://gerrit-review.googlesource.com/#/admin/projects/plugins/github) and do a mvn install from the root directory. This will create two JARs under github-oauth/target and github-plugin/target: the oauth is a JAR library to be copied to $GERRIT_SITE/lib whilst the plugin JAR has to be installed as usual under $GERRIT_SITE/plugins.

Example: git clone https://gerrit.googlesource.com/plugins/github cd github mvn install cp target/github-oauth/target/github-oauth-.jar $GERRIT_SITE/lib cp target/github-plugin/target/github-plugin-.jar $GERRIT_SITE/plugins