Checking package version bump in Gitlab CI/CD

Using Gitlab, you can deploy you package to the Gitlab package repository. This is a great way to share your package with your team, privately or publicly.

In the case of python packages, you cannot deploy a package with the same version number.

Hence, it can be useful to test the version number of the package before deploying it, for instance during a Merge Request.

Getting the current version number

You first need to get the current version number of the package. You can do this by reading the __version__ attribute of the package. In case it is defined in the __init__.py file, you can use the following command:

VERSION=$(grep -oP '(?<=__version__ = ")[^"]*' my_package/__init__.py )

This will store the version number in the VERSION variable. It uses perl regex to extract the anything between __version__ = " and the next ". For instance, if the __init__.py file contains the following line:

__version__ = "0.1.0.rc2"

The VERSION variable will be set to 0.1.0.rc2.

You can adapt this command to your package structure.

Testing the version number

Next, have a look to the package registry to see if the version number is already deployed.

I thought it could be done by using the Gitlab API, but it seems that the API does not provide a way to list the packages in the registry. Hence, a workaround is to try to install the package with the version number and see if it fails.

export PIP_EXTRA_INDEX_URL=https://example.gitlab.com/api/v4/projects/$CI_PROJECT_ID/packages/pypi/simple
pip install --no-deps my_package==$VERSION || exit_code=$?
if [ -z "$exit_code" ]; then
   # if exit_code is empty, then the package is not already published on packages-registry
   echo "Version $VERSION already published on packages-registry"
   exit 1
fi

This will install the package with the version number and store the exit code in the exit_code variable. If the package is already published, the exit code will be 0, and the script will exit with an error code. If the package is not published, the exit code will be different from 0, and the script will continue, allowing the deployment.

Adding it to the Gitlab CI/CD

You can add this test in your .gitlab-ci.yml file, for instance in the test stage:

test-version:
   stage: test
   script:
      - VERSION=$(grep -oP '(?<=__version__ = ")[^"]*' my_package/__init__.py )
      - export PIP_EXTRA_INDEX_URL=https://example.gitlab.com/api/v4/projects/$CI_PROJECT_ID/packages/pypi/simple
      - pip install --no-deps my_package==$VERSION || exit_code=$?
      - |
         if [ -z "$exit_code" ]; then
            echo "Version $VERSION already published on packages-registry"
            exit 1
         fi

You can also add a rules section to run this test only on Merge Requests:

- rules:
   - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'

This way, the test will be run only when a Merge Request is created or updated. And the pipeline will fail if the version number is already published, hence enforcing the version number bump before merging the Merge Request.

Testing Gitlab CI Locally   Manipuler les prévision météorologiques avec Python