Trigger Jenkins job from Gitlab CI with parameters

Question

There is supposed to be a way to trigger a Jenkins job via GitlabCi, using the respective plugin.

My question is whether there is a way:

a) to trigger a parameterized Jenkins job

b) to pass parameters when triggering the job

Solution 1

Here's the way I do it: no plugin required, just triggering Jenkins api from gitlab-ci.

Gitlab-CI

I will assume you have a gitlab-ci runner installed and configured.

First, you need to have a .gitlab-ci.yml file in your project having a basic structure such as:

stages:
- my-jenkins-trigger
variables:
 MY_VARIABLE: "EVERYTHING_IS_AWESOME"

my-jenkins-trigger-job:
 stage: my-jenkins-trigger
 script: curl -i -X POST --user JENKINS_USER:JENKINS_TOKEN JENKINS_JOB_URL/buildWithParameters?MY_JENK_PARAM=${MY_VARIABLE}

In the above, I also assume

• You have a Jenkins job somewhere at URL JENKINS_JOB_URL
• this Jenkins job has a build parameter called MY_VARIABLE
• JENKINS_USER, JENKINS_TOKEN are defined [*]

That simple?

Well yes, but no...

That is the rough structure. That script will merely trigger a Jenkins job and forget about it. You need to work a little more to monitor the job and feed its status back in Gitlab-CI, manage security and possibly get some commit info from gitlab to inject into your job.

Monitoring

In order to have a proper monitoring, I recommand to write a full trigger + monitor + return value script [** ] (in whatever language available or you're familiar with).

Just start by triggering the job as I stated above.

Then, run a while loop (don't forget to put it to sleep [***]) on

curl --silent --user JENKINS_USER:JENKINS_TOKEN JENKINS_JOB_URL/lastBuild/api/json | grep result\":null > /dev/null

until the result of this command is not 0.

Once the Jenkins job is finished, you would probably want to fetch the job's console in Gitlab

curl -i -X POST --user JENKINS_USER:JENKINS_TOKEN JENKINS_JOB_URL/lastBuild/consoleText

Finally you may curl once more on JENKINS_JOB_URL/lastBuild/api/json but this time you grep it on UNSTABLE, SUCCESS or FAILURE.

Discussion

By following the guidelines above, you can fully orchestrate Jenkins jobs from Gitlab-CI. I've posted a long discussion on why and when should you do this.

I hope this will help you.

---

[*] Your Gitlab project Settings > CI/CD > Secret vaiables
[** ] Of course I mean by that to craft a script nicely with params, functions, nice variable names, meaningful logs... You name it.
[***] I found a sleep of 20 seconds worked for me

Solution 2

FWIW, the trigger you referenced originates from Gitlab repository events, not from a GitlabCI execution.

The only possibility (that crosses my mind) of triggering a jenkins job from inside a GitlabCI execution is by having a (custom?) script invoked as part of the GitlabCI execution which remotely activates a Parameterized Trigger Plugin configured for your jenkins job, via a properly-crafted POST request which would include the desired parameters.

See also https://stackoverflow.com/questions/20359810/how-to-trigger-jenkins-builds-remotely-and-to-pass-parameters.

Comments

[Admin]

What are the parameters you want to pass? What action causes a trigger?

[Admin]

At some point I want a gitlab-ci job to invoke jenkins to perform a deployment on an orchestrator (Rancher). The parameters will be the name of the environment and the repo-branch from which the checkout of the code will be performed (so that the images to be deployed are built)

[Admin]

Why do you want to chain two CI systems ? I can't really understand it as gitlab-ci can directly trigger deployments on k8s clusters,so adding jenkins in the middle sounds more adding complexity than helping the situation.

[pkaramol]

that's what I thought also...the question is now how to make gitlab-ci aware of the success/failure of the job triggered via api; think this is ready ootb only for the trigger that originates from gitlab repo events as you say;

[Dan Cornilescu]

Hm, that would be fully managing the jenkins job, not just triggering it... Maybe using GitLab Runner locally to run a custom script which triggers the jenkins job and also monitors its status until completion reporting back the result?

[jimkont]

Can you post a complete example that includes monitoring?

[avi.elkharrat]

It's a while loop, and i could not know your functional. I didn't write out a full example on purpose. I think it would be great if you could do your own!

[mochadwi]

been searching for the "monitoring" parts, I thought it's simple as waiting for the response :D Thanks for sharing this!