Purging a merge request from GitLab

Problem

There is a merge request that shouldn’t exist.

The merge request and all associated data needs to be removed from all affected systems.

For merge request pipelines, related data is stored in various S3 buckets. Details can be found on the internal companion page.

Steps

1. Don’t panic!

2. On the merge request page, switch to the Pipelines tab and cancel all running pipelines. Open each pipeline in a separate browser tab and make sure all child pipelines are properly cancelled as well.

3. Determine all spawned child pipelines. This can be done via something like

   from cki_lib import gitlab
   
   gl_instance, gl_mr = gitlab.parse_gitlab_url(mr_url)
   
   pipeline_urls = [
       gl_bridge.downstream_pipeline['web_url']
       for gl_pipeline in gl_mr.pipelines.list(iterator=True)
       for gl_bridge in gl_instance.projects.get(gl_pipeline.project_id, lazy=True)
           .pipelines.get(gl_pipeline.id, lazy=True).bridges.list(iterator=True)
       if gl_bridge.downstream_pipeline
   ]
   print('\n'.join(pipeline_urls))
   

   For each pipeline, a DataWarehouse checkout like redhat:807685102 should exist.

4. For the S3 buckets above, artifacts are stored per GitLab pipeline ID. With the aws_s3.sh helper in deployment-all, artifacts can be deleted via something like

   for bucket_prefix in "${bucket_prefixes[@]}"; do
       for pipeline_id in "${pipeline_ids[@]}"; do
         ./aws_s3.sh "${bucket_prefix}" \
           s3 rm --dryrun --recursive "s3://BUCKETPREFIX/${pipeline_id}/"
       done
   done
   

   Remove --dryrun once you verified that only the expected objects are going to get deleted.

5. Delete each child pipeline via the Delete button on the pipeline page in the GitLab web interface.

6. Log into the DataWarehouse production instance, and delete the checkouts and connected objects via something like

   KCIDBCheckout.objects.filter(id__in=[f'redhat:{i}' for i in pipeline_ids]).delete()
   

7. Delete the merge request via the Delete button that becomes visible when editing a merge request as a project owner.