Simple Jenkins plugin which helps with automation of KIE CI builds. Tightly coupled with KIE and our workflows. Currently not easily reusable for other projects.
1. Why Jenkins plugin?
Jenkins plugin was chosen after some experimentation with BASH/Groovy scripts. Scripts get messy very fast and it is also usually harder to test them. The plugin nicely encapsulate the needed logic into build steps. This leads to cleaner and maintainable jobs as the configuration is not cluttered with scripts execution.
Jenkins as a system also provides great support for plugins and creating one is rather easy. The only disadvantage is that the plugin upgrade usually requires Jenkins restart.
2. Available extension points
The plugin provides few extension points which can be leveraged in Jenkins jobs.
2.1. Prepare Maven repo cache
This is a build step which takes care of downloading Maven repo cache archive and unpacking the content into
so that it can be used by subsequent Maven executions. It is not strictly necessary to use this step, but it greatly speeds up the build
in case the local repository is empty at the start (which should be the case for multi-repo PR builds). The archive URL is stored in global
configuration. It is currently not possible to use different cache archives for different jobs.
2.2. Upstream repositories builder
This is a build step which adds support for building upstream repositories. Term upstream repository describes a repository which needs be built before some other repository (same relation as upstream Jenkins jobs). This is particularly useful for Pull Request (PR) which span multiple repositories. In order to make sure the build passes in one repository, Jenkins needs to use correct fork and branch which contains additional changes in one or more of the upstream repositories. Dependent PRs are matched by branch name (e.g. same branch name needs to be used for both PRs which are in different repositories). The relation between repositories is currently hard-coded in the plugin logic.
2.3. Downstream repositories builder
Very similar to the above upstream repositories builder. Mainly used to verify that downstream repositories are not affected by the changes to the current repository. Downstream builds are thus, by default, executed with tests. It has the same features as upstream repositories builder - it can determine if the downstream repositories need different base repository/branch based on the config and status of that branch (e.g. if there is a open PR associated with the branch).
3. Installing the plugin
The plugin is not available in any public Jenkins repository, and likely will never be, as the plugin is very tightly coupled
with our workflows and in the current form is not re-usable outside of KIE builds. When installing the plugin one needs to manually
build this project by running
mvn clean package and upload the resulting
.hpi file using the Jenkins UI. To upload the newly
built plugin go to
Manage Jenkins → Manage Plugins → Advanced, choose the
.hpi file under
Upload Plugin section
Upload. You will also need to restart the Jenkins, so that it can pick up the new plugin version.
Plugin stores common configuration as a section in global Jenkins configuration (
Manage Jenkins → Configure System).
For upstream repositories builder you need to configure GitHub access token, otherwise the plugin won’t be able to communicate
with the GitHub’s REST API (see Creating access token
for a more info). You can also specify URL of tar.gz archive with the Maven repo cache content and additional
Maven related configuration options like MAVEN_HOME, MAVEN_OPTS and argument lines for upstream builds.
In case you want to use one of the extension points specified above, just go to your job configuration and add specific build steps.
use Credentials Plugin to store/retrieve the GitHub API access token
add extension (build step) for automated creation of new GitHub PRs