Table of Contents

• Introduction
• User support
• Known bugs/issues
• Supported GitLab versions
• Supported GitLabCI Functions
• Configuring access to GitLab
  • Jenkins Job Configuration
  • Gitlab Configuration (7.14.x)
  • Gitlab Configuration (>= 8.1)
  • Forked repositories
• Branch filtering
• Build Tags
• Parameterized builds
• Contributing to the Plugin
• Quick test environment setup using Docker
  • Access GitLab
  • Access Jenkins
• Release Workflow

Introduction

This plugin allows GitLab to trigger builds in Jenkins after code is pushed and/or after a merge request is created.

User support

If you have a problem or question about using the plugin, please make sure you are using the latest version. Then create an issue in the GitHub project if necessary. New issues should include the following:

• GitLab plugin version (e.g. 1.2.0)
• GitLab version (e.g. 8.1.1)
• Jenkins version (e.g. 1.651.1)
• Relevant log output from the plugin (see below for instructions on capturing this)

Version 1.2.0 of the plugin introduced improved logging for debugging purposes. To enable it:

1. Go to Jenkins -> Manage Jenkins -> System Log
2. Add new log recorder
3. Enter 'Gitlab plugin' or whatever you want for the name
4. On the next page, enter 'com.dabsquared.gitlabjenkins' for Logger, set log level to FINE, and save
5. Then click on your Gitlab plugin log, click 'Clear this log' if necessary, and then use GitLab to trigger some actions
6. Refresh the log page and you should see output

You can also try chatting with us in the #gitlab-plugin channel on the Freenode IRC network.

Known bugs/issues

This is not an exhaustive list of issues, but rather a place for us to note significant bugs that may impact your use of the plugin in certain circumstances. For most things, please search the Issues section and open a new one if you don't find anything.

• #272 - Plugin version 1.2.0+ does not work with GitLab Enterprise Edition < 8.8.3, due to a bug on their side.
• Jenkins versions 1.651.2 and 2.3 removed the ability of plugins to set arbitrary job parameters that are not specifically defined in each job's configuration. This was an important security update, but it has broken compatibility with some plugins, including ours. See here for more information and workarounds if you are finding parameters unset or empty that you expect to have values.

Supported GitLab versions

• 7.14.x where it emulates Jenkins as a GitLabCI Web Service
• 8.1.x and newer via the new commit status API that supports with external CI services like Jenkins

Note: GitLab version 8.0.x is not supported! In this version, GitLab folded the GitLabCI functionality into core GitLab, and in doing so broke the ability for the plugin to give build status to GitLab. Jenkins build status will never work with GitLab 8.0.x!

Supported GitLabCI Functions

• /project/PROJECT_NAME/builds/COMMIT_SHA1/status.json (used for Merge Request pages) returns build result for Merge Request build with COMMIT_SHA1 as last commit
• /project/PROJECT_NAME/builds/status.png?ref=BRANCH_NAME returns build status icon for latest build for BRANCH_NAME
• /project/PROJECT_NAME/builds/status.png?sha1=COMMIT_SHA1 returns build status icon for latest build for COMMIT_SHA1 as last commit
• /project/PROJECT_NAME/builds/COMMIT_SHA1 redirects to build page of the last build containing COMMIT_SHA1 as last commit
• /project/PROJECT_NAME/commits/COMMIT_SHA1 redirects to build page of the last build containing COMMIT_SHA1 as last commit
• /project/PROJECT_NAME?ref=BRANCH_NAME redirects to build page of the last build for BRANCH_NAME
• /project/PROJECT_NAME triggers a build, type (Merge Request or Push) depending on payload

Configuring access to GitLab

Optionally, the plugin communicates with the GitLab server in order to fetch additional information. At this moment, this information is limited to fetching the source project of a Merge Request, in order to support merging from forked repositories.

To enable this functionality, a user should be set up on GitLab, with GitLab 'Developer' permissions, to access the repository. You will need to give this user access to each repo you want Jenkins to be able to clone. Log in to GitLab as that user, go to its profile, and copy its secret API key. On the Global Configuration page in Jenkins, supply the GitLab host URL, e.g. http://your.gitlab.server. Click the 'Add' button to add a credential, choose 'Secret text' as the kind of credential, and paste your GitLab user's API key into the 'Secret' field. Testing the connection should succeed.

Jenkins Job Configuration

Git configuration for Freestyle jobs

1. In the Source Code Management section:
   1. Click Git
   2. Enter your Repository URL (e.g.: git@your.gitlab.server:group/repo_name.git)
   • In the Advanced settings, set its Name to origin
   3. To be able to merge from forked repositories:
      Note: this requires configuring communication to the GitLab server
   • Add a second repository with:
     • URL: ${gitlabSourceRepoURL}
     • Name (in Advanced): ${gitlabSourceRepoName}
   4. In Branch Specifier enter:
   • For single-repository setups: origin/${gitlabSourceBranch}
   • For forked repository setups: ${gitlabSourceRepoName}/${gitlabSourceBranch}
   5. In Additional Behaviours:
      • Click the Add drop-down button.
      • Select Merge before build from the drop-down.
      • Set *Name of the repository" to origin
      • Set Branch to merge as ${gitlabTargetBranch}

Note: Since version 1.2.0 the gitlab-plugin sets the gitlab hook values through environment variables instead of build parameters. To set default values, consult EnvInject Plugin.

Git configuration for Pipeline/Workflow jobs

Incompatibility note: When upgrading to version 1.2.1 or later of the plugin, if you are using Pipeline jobs you will need to manually reconfigure your Pipeline scripts. In older versions the plugin set global Groovy variables that could be accessed as e.g. {gitlabSourceBranch}. After version 1.2.1, these variables are only accessible in the env[] map. E.g. {env.gitlabSourceBranch}.

• A Jenkins Pipeline bug will prevent the Git clone from working when you use a Pipeline script from SCM. It works if you use the Jenkins job config UI to edit the script. There is a workaround mentioned here: https://issues.jenkins-ci.org/browse/JENKINS-33719
• Pipeline Multibranch jobs are not currently supported. See https://github.com/jenkinsci/gitlab-plugin/issues/298

1. Use the Snippet generator, General SCM step, to generate sample Groovy code for the git checkout/merge etc.
2. Example that performs merge before build: checkout changelog: true, poll: true, scm: [$class: 'GitSCM', branches: [[name: "origin/${env.gitlabSourceBranch}"]], doGenerateSubmoduleConfigurations: false, extensions: [[$class: 'PreBuildMerge', options: [fastForwardMode: 'FF', mergeRemote: 'origin', mergeStrategy: 'default', mergeTarget: "${env.gitlabTargetBranch}"]]], submoduleCfg: [], userRemoteConfigs: [[name: 'origin', url: 'git@mygitlab:foo/testrepo.git']]]

Freestyle and Pipeline jobs

1. In the Build Triggers section:
   • Check the Build when a change is pushed to GitLab.
   • Use the check boxes to trigger builds on Push and/or Merge Request events
   • Optionally enable building open merge requests again after a push to the source branch.
2. Configure any other pre build, build or post build actions as necessary
3. Click Save to preserve your changes in Jenkins.

Matrix/Multi-configuration jobs

The Jenkins Matrix/Multi-configuration job type is not supported.

Gitlab Configuration (7.14.x)

• In GitLab go to your repository's project Settings
  • Click on Services
  • Click on GitLab CI
    • Check the Active checkbox
    • For Token put any random string (This is not yet functioning)
    • For Project URL put http://JENKINS_URL/project/PROJECT_NAME
    • Click Save
  • Click on Web Hooks
    • Add a Web Hook for Merge Request Events to http://JENKINS_URL/project/PROJECT_NAME
      Note: GitLab for some reason does not send a merge request event with the GitLab Service.

Gitlab Configuration (>= 8.1)

GitLab 8.1 has implemented a commit status api, you need an extra post-build step to support commit status.

• In GitLab go to you primary repository's project Settings

  • Click on Web Hooks
  • Add a Web Hook for Merge Request Events and Push Events to http://JENKINS_URL/project/PROJECT_NAME
    

• If you plan to use forked repositories, you will need to enable the GitLab CI integration on each fork.

  • Go to the Settings page in each developer's fork
  • Click on Services
  • Click on Web Hooks
  • Add a Web Hook for Merge Request Events and Push Events to http://JENKINS_URL/project/PROJECT_NAME
    Note: You do not need to select any "Trigger Events" as the Web Hook for Merge Request Events will alert Jenkins.

• Add a post-build step Publish build status to GitLab commit (GitLab 8.1+ required) to the job.

• For pipeline jobs surround your build step with the gitlabCommitStatus step like this:

  gitlabCommitStatus {
      <script that builds your project>
  }
  

• Configure access to GitLab as described above in "Configure access to GitLab" (the account needs at least developer permissions to post commit statuses)

Forked repositories

If you plan to use forked repositories, you will need to enable the GitLab CI integration on each fork.

• Go to the Settings page in each developer's fork
• Click on Services
  • Click on GitLab CI
    • Check the Active checkbox
    • For Token put any random string (This is not yet functioning)
    • For Project URL put http://JENKINS_URL/project/PROJECT_NAME
    • Click Save
      Note: You do not need to select any "Trigger Events" as the Web Hook for Merge Request Events will alert Jenkins.

In addition, you will need to make sure that the Git plugin has an appropriate setting for user.name and user.email in the global Jenkins configuration. This is good practice generally, but is required for forked repos to work.

1. Click on Manage Jenkins, then Configure System
2. Under the Git Plugin section, set something for 'Global Config user.name Value' and 'Global Config user.email Value'

Branch filtering

Triggers may be filtered based on the branch name, i.e. the build will only be allowed for selected branches. On the project configuration page, when you configure the GitLab trigger, you can choose 'Filter branches by name' or 'Filter branches by regex.' Filter by name takes comma-separated lists of branch names to include and/or exclude from triggering a build. Filter by regex takes a Java regular expression to include and/or exclude.

Note: This functionality requires accessing the GitLab server (see above) and for the time being also a git repository url already saved in the project configuration. In other words, when creating a new project, the configuration needs to be saved once before being able to select the allowed branches. For Workflow/Pipeline jobs, the configuration must be saved and the job must be run once before the list is populated. For existing projects, all branches are allowed to push by default.

Build Tags

In order to build when a new tag is pushed:

• In the GitLab server add Tag push events to the Web Hook
• In the Jenkins under the Source Code Management section:
  • select Advance... and add +refs/tags/*:refs/remotes/origin/tags/* as Refspec
  • you can also use Branch Specifier to specify which tag need to be built (exampple refs/tags/${TAGNAME})

Parameterized builds

You can trigger a job a manually by clicking This build is parameterized and adding the any of the relevant build parameters. These include:

• gitlabBranch
• gitlabSourceBranch
• gitlabActionType
• gitlabUserName
• gitlabUserEmail
• gitlabSourceRepoHomepage
• gitlabSourceRepoName
• gitlabSourceNamespace
• gitlabSourceRepoURL
• gitlabSourceRepoSshUrl
• gitlabSourceRepoHttpUrl
• gitlabMergeRequestTitle
• gitlabMergeRequestDescription
• gitlabMergeRequestId
• gitlabMergeRequestIid
• gitlabTargetBranch
• gitlabTargetRepoName
• gitlabTargetNamespace
• gitlabTargetRepoSshUrl
• gitlabTargetRepoHttpUrl

Contributing to the Plugin

Plugin source code is hosted on Github. New feature proposals and bug fix proposals should be submitted as Github pull requests. Fork the repository on Github, prepare your change on your forked copy, and submit a pull request (see here for open pull requests). Your pull request will be evaluated by the Cloudbees Jenkins job.

If you are adding new features please make sure that they support the Jenkins Workflow Plugin. See here for some information.

Before submitting your change make sure that:

• your changes work with the oldest and latest supported GitLab version
• new features are provided with tests
• refactored code is provided with regression tests
• the code formatting follows the plugin standard
• imports are organised
• you updated the help docs
• you updated the README
• you have used findbugs to see if you haven't introduced any new warnings.

Quick test environment setup using Docker

In order to test the plugin on different versions of GitLab and Jenkins you may want to use Docker containers.

A example docker-compose file is available at gitlab-plugin/src/docker which allows to set up instances of the latest GitLab and Jenkins versions.

To start the containers, run below command from the docker folder:

docker-compose up -d

Access GitLab

To access GitLab, point your browser to http://localhost:10080 and set a password for the root user account.

For more information on the supported GitLab versions and how to configure the containers, visit Sameer Naik's github page at https://github.com/sameersbn/docker-gitlab.

Access Jenkins

To see Jenkins, point your browser to http://localhost:8080.

For more information on the supported Jenkins tags and how to configure the containers, visit https://hub.docker.com/r/library/jenkins.

Release Workflow

GitLab-Plugin admins should adhere to the following rules when releasing a new plugin version:

• Ensure codestyle conformity
• Run unit tests
• Run manual tests on both, oldest and latest GitLab versions
• Update documentation
• Create change log
• Create release tag
• Create release notes (on github)