Run a pipeline cleanup automatically after a merge request was merged

Question

We are in the process of adding dynamic deploys to a testing environment where each merge request gets its own url, to be able to manually do frontend testing for people who are not developers.

These instances are deployed with docker-compose and GitLab CI/CD which works well.

I now want to automatically shut down these instances, once the merge request is merged.

So far, I have this extra step to manually shut down the testing instance:

deploy-dynamic-down:
  tags:
    - docker
  stage: deploy-dynamic
  script:
   - docker-compose down
  when: manual

This works well, but requires a manual step which will almost certainly be forgotten every now and then, requiring us to clean our runner every now and then.

So, my question is: can I trigger this pipeline step to run only when a merge request is merged?

I can't just limit this pipeline to certain branches like master or develop, because we don't always create merge requests to only these branches. I don't know which branch the merge request will target beforehand.

Answer 1

You can use Gitlab Environments to achieve this.

You can configure a dynamic gitlab environment to be created for each one of your testing environments.

You can set your deploy-dynamic-down step to be executed when the testing environment is stopped.

The key part here is that the environment will be automatically stopped when the source branch is deleted.

Workflow:

1. Create a feature branch
2. Deploy a testing environment
3. Create a merge request (Check the Delete source branch when merge request is accepted. checkbox) You can also check Delete source branch when merging a Merge Request.
4. When the merge request is accepted, the feature branch will be deleted, and the corresponding gitlab environment will be stopped. This will trigger the deploy-dynamic-down step.