Keeping in touch with your pipeline Jenkins jobs

We are using continuous integration (CI) at the Softwareschneiderei for many years now. Our CI platform of choice is historically Jenkins which was called Hudson back in the day.

Things moved on since then and the integration with GitLab got a lot better with the advent of multibranch pipeline jobs. This kind of job allows you to automatically build branches and merge requests within the same job and keep the builds separate.

Another cool feature of Jenkins is the job configuration as code, defined in Jenkinsfile and used in pipeline jobs. That way it is easy to create and maintain a job configuration alongside your project’s source code inside your repository. No need anymore to click through pages of web UIs to configure your job. That way you also get the complete job configuration change history as additional benefits.

I prefer using scripted instead of declarative pipelines for Jenkinsfiles because they give me more control, freedom and power. But like always, this power and flexiblity comes at a price…

Sending out build notifications

In my case I wanted to always send out build notification regardless of the job result. This is quite easy if you have plugins like the Mattermost Notification Plugin or one of the mail plugins. Since our pipeline script consists of Groovy code this seems quite straightforward: Put the notification code into a try-finally-block:

node {
    try {
        stage ('Checkout and build') {
            checkout scm
			// Do something to build our project
		}
		// Maybe some additional stages like testing, code-analysis, packaging and deployment
    } finally {
        stage ('Notify') {
            mattermostSend "${env.JOB_NAME} - ${currentBuild.displayName} finished with Status [${currentBuild.currentResult}] (<${env.BUILD_URL}|Open>)"
        }
    }
}

Unfortunately, this pipeline script will always return SUCCESS as the build result! Even if someone aborts the job execution or a stage in the try-block fails…

Managing build status

So the seasoned programmer probably already knows the fix: Setting the build result in appropriate catch-blocks:

node {
    try {
        stage ('Checkout and build') {
            checkout scm
			// Do something to build our project
		}
		// Maybe some additional stages like testing, code-analysis, packaging and deployment
    } catch (Exception e) {
        if (e in org.jenkinsci.plugins.workflow.steps.FlowInterruptedException) {
            currentBuild.result = 'ABORTED'
        } else {
            echo "Exception: ${e.class}, message: ${e.message}"
            currentBuild.result = 'FAILURE'
        }
    } finally {
        stage ('Notify') {
            mattermostSend "${env.JOB_NAME} - ${currentBuild.displayName} finished with Status [${currentBuild.currentResult}] (<${env.BUILD_URL}|Open>)"
        }
    }
}

You can control the granularity and the exceptions thrown by your build steps at will and implement exactly the status reporting that you want. The available statuses are defined in hudson.model.Result, so feel free to realize your own build status management to best fit your project.

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