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

Answer 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

Answer 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.

Answer 3

If you want to keep it simple, try the generic webhook trigger plugin.

https://plugins.jenkins.io/generic-webhook-trigger

You can trigger a build by sending an http POST using a JSON body or URL parameters.

Parse the JSON request

def req = readJSON text: payload

Now you can use it in your pipeline assuming you had a deploy function.

deploy(req.environment, req.branch)

I must agree with @Tensibai. Two CI/CD systems on the surface does seem overly complex. You might want to consider sticking with one if possible.

Answer 4

I use a similar setup as this answer.

Difference is I cannot poll the latest job because it may refer to a job I didn't start. So instead I get the queue ID from the response headers when triggering a job, and match that with the queue ID of most recent job runs.

I did this in Python because it makes things a bit easier, but it could also be done using sh.

GitLab CI config:

Test:
  stage: test
  script:
    - run_jenkins_job.py
      --docker-image "${CI_REGISTRY_IMAGE}"
      --display-name "Test ${CI_COMMIT_REF_SLUG}"

run_jenkins_job.py:

#!/usr/bin/env python3
import argparse
import sys
import time

import requests

JENKINS_JOB_URL = "https://jenkins.example.org/job/MYJOB"
JOB_BUILD_TOKEN = "MYJOBTOKEN"

api_req = requests.Session()
api_req.headers.update(
    {
        "Authorization": "Basic BASIC_USER_AUTH",
        "Content-Type": "application/x-www-form-urlencoded",
    }
)


def main():
    parser = argparse.ArgumentParser(description="Run a GitLab MR job on Jenkins and poll for the result.")
    parser.add_argument("--docker-image", required=True, type=str)
    parser.add_argument("--display-name", required=True, type=str)
    args = parser.parse_args(sys.argv[1:])

    queue_id = schedule_build(args)
    exit_code = poll_build(queue_id)
    sys.exit(exit_code)


def schedule_build(args: argparse.Namespace) -> int:
    response = api_req.post(
        f"{JENKINS_JOB_URL}/buildWithParameters?token={JOB_BUILD_TOKEN}",
        data={
            "docker_image": args.docker_image,
            "display_name": args.display_name,
        },
    )
    response.raise_for_status()
    location_header_value = response.headers["Location"]
    # Example location header: "https://jenkins.example.org/queue/item/123/"
    return int(location_header_value.rstrip("/").split("/")[-1])


def poll_build(queue_id: int) -> int:
    job_url_shown = False

    for _ in range(300):
        time.sleep(15)
        response = api_req.get(f"{JENKINS_JOB_URL}/api/json?tree=builds[result,queueId,url]")
        response.raise_for_status()

        for build in response.json()["builds"]:
            if build["queueId"] != queue_id:
                continue
            elif build["result"] is None:
                if not job_url_shown:
                    # Scheduled job first appeared; show URL.
                    print(f"\nRunning: {build['url']}\n")
                    job_url_shown = True
                print(".", end="", flush=True)
            else:
                if build["result"] == "SUCCESS":
                    return 0
                else:
                    return 1


if __name__ == "__main__":
    main()