Dockerdd is a simple Python script to replicate Docker images between registries.

If you have multiple registries and want to keep some images in sync, this script might be your solution. You simply describe the sync in a yaml file and run the script.

To run this script, you will need:

• Python (including pip)
• Docker
• Python's Docker library

To install the Docker library for Python, run the following command:

pip install docker

This is the structure of a jobs file, it's in yaml format:

registries:
  <registry-name>:
    address: <registry url without the 'http(s)://', or use 'default'>
    folder: <an optional folder name to use at the target registry>
  <registry-name-2>:
    address: ...
  <registry-name-3>:
    address: ...
    folder: ...

imagelists:
  <imagelist-name>:
    - image1:tag
    - image2:tag
    - image3:tag
  <imagelist-name-2>:
    - ...

jobs:
  <job-name>:
    source: <source registry-name>
    target: <target registry-name>
    imagelists:
      - <imagelist-name-1>
      - <imagelist-name-2>
      - ...
  <job-name-2>:
    source: ...
    ...

First define the registries you want to use. Define the registry's address, e.g. harbor.mydomain.com/dev-images. You can also use 'default', in that case Docker will use the default registry as defined by the Docker configuration. Optionally define a target folder location. If folder is not defined, the root of the target repository will be used.

Next define imagelists. Each imagelist has a name and contains a list of images (with tags).

Finally defines jobs. Each job copies the given imagelists from the given source registry to the target registry.

You can define multiple jobs and imagelists. Jobs will be performed in the given order.

dockerdd.py <jobs-file>

Some registries require authentication, this is not handled by Dockerdd. You can authenticate once (manually) using docker login, the secrets will be stored in ~/.docker/config.json.

The file example-gitlab-ci.yml demonstrates you how you can run this script in a pipeline.

Copyright (C) Ernest Neijenhuis PA3HCM

Dockerdd is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Dockerdd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Dockerdd. If not, see http://www.gnu.org/licenses/.

• Author: Ernest Neijenhuis
• Code on Github: https://github.com/pa3hcm/dockerdd