Script used to move all container images from one Gitlab registry to another, including every tag. This script first pulls all containers with all tags to the system running the script, then retags with the new registry and pushes the images to the target repository.

gitlab_clone_registry.py

import json
import sys

import requests
from docker.errors import DockerException

try:
    import docker
except ImportError:
    sys.exit("Please run 'pip install docker' first")


class GitlabContainerRegistry:
    def __init__(self, gitlab_project, gitlab_token):
        self.gitlab_project = gitlab_project
        self.gitlab_token = gitlab_token
        self.gitlab_url = (
            "https://gitlab.com/api/v4/projects/"
            + gitlab_project
            + "/registry/repositories"
        )

    def pretty_print_repositories(self, repositories_dict):
        repositories = json.dumps(repositories_dict, indent=4)
        print(repositories)

    def get_repositories(self):
        response = requests.get(
            self.gitlab_url, headers={"PRIVATE-TOKEN": self.gitlab_token}
        )
        if response.status_code != 200:
            raise Exception(response.text)
        repositories = response.json()
        self.enrich_repositories_with_tags(repositories)
        return repositories

    def enrich_repositories_with_tags(self, repositories):
        for repository in repositories:
            repository["tags"] = self.get_repository_tags(repository["id"])

    def get_repository_tags(self, repository_id):
        response = requests.get(
            self.gitlab_url + "/" + str(repository_id) + "/tags",
            headers={"PRIVATE-TOKEN": self.gitlab_token},
        )
        if response.status_code != 200:
            raise Exception(response.text)
        return response.json()


class DockerPuller:
    def __init__(self, username, password):
        try:
            self.client = docker.from_env()
            self.auth = {
                "username": username,
                "password": password,
            }
        except DockerException as e:
            print("Is Docker running?")
            sys.exit("Could not connect to docker daemon: " + str(e))

    def pull_image(self, image_name, all_tags=True):
        print("Pulling " + image_name)
        self.client.images.pull(image_name, all_tags=all_tags, auth_config=self.auth)
        print("Done")


class DockerPusher:
    def __init__(self, username, password):
        try:
            self.client = docker.from_env()
            self.auth = {
                "username": username,
                "password": password,
            }
        except DockerException as e:
            print("Is Docker running?")
            sys.exit("Could not connect to docker daemon: " + str(e))

    def push_images_to_registry(self, source_registry, target_registry):
        images = self.client.images.list()
        for image in images:
            for tag in image.tags:
                if tag.startswith(source_registry):
                    print("Pushing " + tag)
                    new_tag = self.retag_image(
                        image, tag, target_registry
                    )  # Retag does not remove original tags
                    self.client.images.push(new_tag, auth_config=self.auth)
                    print("Pushed " + new_tag)
                else:
                    print(
                        "Skipping " + tag + " as it does not match " + source_registry
                    )

    def retag_image(self, image, tag, registry_path):
        image_name_clean = tag.split("/")[-1]
        new_tag = registry_path + image_name_clean
        image.tag(new_tag)
        return new_tag


# Most of the wisdom comes from https://docs.gitlab.com/ee/api/container_registry.html
# To get your project ID, go to the project page and open "Project settings"
# It's the number shown next to the project name

# Step 0:
# Decide on either 2 project tokens or a single personal token
# You need the "developer" role and read_registry permission scope

source_project_id = "12345678"
source_project_token = "glpat-sometoken"
source_registry_url = "registry.gitlab.com/groupname/projectname/"
target_project_token = "glpat-someothertoken"
target_registry_url = "registry.gitlab.com/newgroupname/newprojectname/"

# Step 1: Gather required docker image names
gitlab_container = GitlabContainerRegistry(source_project_id, source_project_token)
repositories = gitlab_container.get_repositories()
# This just gets all tag information
# gitlab_container.pretty_print_repositories(repositories)

# Step 2: Pull all image names to local
docker_puller = DockerPuller("gitlab-ci-token", source_project_token)
for repository in repositories:
    docker_puller.pull_image(repository["location"], all_tags=True)

# Step 3: Retag and push all images to new registry
# Source registry is mentioned here as it is in the container tags
# This step will not contact the source registry
docker_pusher = DockerPusher("gitlab-ci-token", target_project_token)
docker_pusher.push_images_to_registry(
    source_registry=source_registry_url,
    target_registry=target_registry_url,
)