Trigger on all branches and ignore pulls

Build Environment
1

I have build forked PRs feature turned on in my project. I have two workflows:

pre-merge: this triggers when a PR is pushed to my project
merge: this triggers when there’s an update to the master branch. like a merge to master

Here’s my workflow:

workflows:
  pre-merge:
    jobs:
      - build
      - lint-and-unit-tests:
          requires:
              - build
  merge:
    jobs:
      - build:
          filters:
            branches:
              only: master
      - lint-and-unit-tests:
          requires:
            - build
          filters:
            branches:
              only: master
      - integration-tests:
          context: sceptre-core
          requires:
            - build
          filters:
            branches:
              only: master

The change I want to make is to have the merge workflow to trigger on any changes to any branch but also don’t run the pre-merge workflow when that happens. I’ve read the circleci trigger docs and I still cannot figure out a way to do it. Can someone please help?

2

Hi @zaro0508 ,

Thank you for the question!

I believe that when pull requests are opened, the text pull/ is contained in the branch name.
We can use this to filter the branches for which jobs are executed upon.

First, we can set the job filtering to the following conditions:

  1. For the pre-merge workflow, filter the jobs to only run if pull/ is included in the branchname
  2. For the merge workflow, filter the jobs to only run if pull/ is not included in the branchname

Since this syntax can get kind of long when specifying it for multiple jobs, I will use yaml aliases to simplify it (I am using negative lookaheads here, but if there are issues with this, then using the ignore key could replace them):

pre-merge: &pre-merge
  filters:
    branches:
      only: /^(pull\/).*$/
 
merge: &merge
  filters:
    branches:
      only: /^(?!pull\/).*$/

If we use this in the workflows, it would look something like this:

workflows:
  pre-merge:
    jobs:
      - build:
          <<: *pre-merge
      - lint:
          <<: *pre-merge
  merge:
    jobs: 
      - build:
          <<: *merge

By having the filter condition for every job, if no jobs are to be run for a workflow, the workflow will not execute.

Another method would be to check for the value of environment variables such as CIRCLE_PULL_REQUEST. Then you could cancel a workflow based on if it is defined or not (as this variable is only present in jobs triggered by a PR ).

One caveat with this approach is that a workflow will actually be triggered on CircleCI, but it will be immediately canceled. The filter approach I mentioned earlier will not trigger a workflow on CircleCI.

Let me know if this points you in the right direction, and if I seem to have misunderstood your question, please let me know and I am happy to take another look!