This action query a docker container registry to check if a given tag exists.

As a user I want to know if a docker image tag already exists in a registry, this is required to prevent same commit to be build more then once (f.e. re-tagging an existing image after a release workflow).

In order to be able to determine if the container image already exists we can try to get the manifest data from the registry. If the manifest exists the image + tag exists otherwise the request will fail and the image tag is not found.

First implementation is currently tested, use at own risk

• tested docker.io Registry
• tested ghcr.io Registry
• tested Google Artifact Registry
• tested Amazon Elastic Container Registry

The return message of the registry is not standarized, please open a PR or create an issue if you encounter trouble with your registry.

- uses: tyriis/[email protected]
  with:
    # The container image name
    image: ''

    # The container image tag
    tag: ''

The scripts and documentation in this project are released under the MIT License