gitlab-cleanup-docker-registry-images.py

from typing import List

import os
# pip install python-gitlab
from gitlab import Gitlab
from gitlab.v4.objects import Project, ProjectRegistryRepository, GitlabDeleteError

if __name__ == '__main__':
    gl = Gitlab(os.environ['GITLAB_URL'], private_token=os.environ['TOKEN'])
    projects: List[Project] = gl.projects.list(all=True)
    for project in projects:
        repositories: List[ProjectRegistryRepository] = project.repositories.list()
        for repository in repositories:
            print(f'Cleaning {repository.location}')
            try:
                repository.tags.delete_in_bulk(name_regex=".*", keep_n=5, older_than="1w")
            except GitlabDeleteError as e:
                if 'once an hour' not in str(e):
                    raise e

after running this script, you should delete unreferenced registry layers by running following cmd:

gitlab-ctl registry-garbage-collect -m