Test & build a project on Jenkins CI
Application tests run in a continuous integration (CI) environment.
https://ci.integration.publishing.service.gov.uk/
Read here about the CI infrastructure.
Setting up
1. Create the job in Jenkins
You need to add your repo to the govuk_ci::master::pipeline_jobs in govuk-puppet. This will create the job in Jenkins.
2. Add a Jenkinsfile
Your repo needs to contain a Jenkinsfile in the root which has
details of how the application is built. In most cases the Jenkinsfile will need to run the tests for your project. For applications the build process includes creating a release tag. For gems the build process includes releasing the packaged gem to rubygems.org.
The following Jenkinsfile should be sufficient for most projects:
#!/usr/bin/env groovy
library("govuk")
node {
govuk.buildProject()
}
Read the documentation for this in alphagov/govuk-jenkinslib
3. Trigger builds from GitHub
Builds are triggered using a GitHub "service". From a project's GitHub settings, add the "Jenkins (GitHub plugin)" service to point to:
https://ci.integration.publishing.service.gov.uk/github-webhook/
See content-store's configuration for an example.
4. Branch indexing
Once your Jenkinsfile is on a branch, you can go to your job in new Jenkins and
run "Branch Indexing" from the menu. This should trigger a build of all branches
with a Jenkinsfile, which should be your new branch. Any open branches need to be rebased after you've merged your Jenkinsfile into master.
5. Set up schema testing
Many GOV.UK applications test against the content schemas.
To test your application for each PR on govuk-content-schemas, add it to the govuk-content-schemas Jenkinsfile.
Fixing the build number
Master branch builds are often tagged with the Jenkins build number so that a specific version can be deployed to each environment.
This can fail if the build number is reset, for example if all the old builds are deleted or if a job is migrated from a different CI server. The error will be something like this:
fatal: tag 'release_1' already exists
To fix this, set the build number to the next release number using the Jenkins script console:
def job = Jenkins.instance.getItemByFullName("your-project-name/master")
job.nextBuildNumber = 1234
job.save()