Can a single seed job process DSLs from multiple repos?

Question

I recently managed to convert several manually-created jobs to DSL scripts (inlined into temporary 'seed' jobs), and was pleasantly surprised how straightforward it was. Now I'd like to get rid of the multiple seed jobs and try to structure things more cleanly.

To that end, I created a new jenkins-ci repo and committed all the Groovy DSL scripts to it. Then I created a job-generator Jenkins job that pulls from the jenkins-ci repo and has a single Process Job DSLs step. This step has the Look on Filesystem box ticked, with the DSL Scripts field set to jobs/*.groovy. With global push notifications already in place, this works more-or-less as intended: if I make a change to the jenkins-ci repo, the job-generator job automatically runs and regenerates all the jobs—awesome!

What I don't like about this solution is that it has poor locality of reference: the DSL scripts for the job live in a completely separate repository from the code. What I'd really like is to keep the job DSL scripts in each individual code repository, in a jenkins subfolder, and have a single seed job that processes them all. That way, changes to CI setup could be code-reviewed right alongside the code. To me, that just feels like an ideal setup.

Unfortunately, I don't have a clear idea about how to make this happen. If I could figure out a way to make the seed job watch multiple repos, such that a commit to any one of them would trigger it, perhaps I could inject another build step before the Process Job DSLs step and (somehow) script my way to victory, but... I'm unsure how to even get to that point. (I certainly don't want to do full clones of each repo in the generator job just to pull in the DSL scripts!)

I suspect I'm not the first person to wish they could put the Job DSL scripts alongside the code, though perhaps I'm over-estimating the benefits. Any advice on this topic would be much appreciated—thanks!

Answer 1

Unfortunately there is no direct way of solving this. Several feature requests have been opened (JENKINS-33275, JENKINS-37220), but AFAIK no one is working on any of them.

As a workaround you can use the Pipeline Multibranch Plugin and create a multibranch project for each of your repositories. You must then add a simple Jenkinsfile to each repo/branch and use the Jenkinsfile to execute your Job DSL scripts. See Use Job DSL in Pipeline scripts for details. This would require minimal coding, but I think each repo must be cloned for this to work because the Job DSL files must be available on the file system.

You can use Job DSL to create the multibranch jobs, see multibranchPipelineJob in the API viewer. This would be your "root" seed job.

If your repos are hosted on GitHub, you can also checkout the GitHub Organization Folder Plugin. With that plugin you must only create one job for each organization instead of multiple multibranch jobs.