Development and maintenance

For development on the openeo package itself, it is recommended to install a local git checkout of the project in development mode (-e) with additional development related dependencies ([dev]) like this:

pip install -e .[dev]

If you are on Windows and experience problems installing this way, you can find some solutions in section Development Installation on Windows.

Running the unit tests

The test suite of the openEO Python Client leverages the nice pytest framework. It is installed automatically when installing the openEO Python Client with the [dev] extra as shown above. Running the whole tests is as simple as executing:


There are a ton of command line options for fine-tuning (e.g. select a subset of tests, how results should be reported, …). Run pytest -h for a quick overview or check the pytest documentation for more information.

For example:

# Skip tests that are marked as slow
pytest -m "not slow"

Building the documentation

Building the documentation requires Sphinx and some plugins (which are installed automatically as part of the [dev] install).

Quick and easy

The easiest way to build the documentation is working from the docs folder and using the Makefile:

# From `docs` folder
make html

(assumes you have make available, if not: use python -msphinx -M html .  _build.)

This will generate the docs in HTML format under docs/_build/html/. Open the HTML files manually, or use Python’s built-in web server to host them locally, e.g.:

# From `docs` folder
python -m http.server 8000

Then, visit in your browser

Like a Pro

When doing larger documentation work, it can be tedious to manually rebuild the docs and refresh your browser to check the result. Instead, use sphinx-autobuild to automatically rebuild on documentation changes and live-reload it in your browser. After installation (pip install sphinx-autobuild in your development environment), just run

# From project root
sphinx-autobuild docs/ --watch openeo/ docs/_build/html/

and then visit . When you change (and save) documentation source files, your browser should now automatically refresh and show the newly built docs. Just like magic.

Contributing code

User contributions (such as bug fixes and new features, both in source code and documentation) are greatly appreciated and welcome.

Pull requests

We use a traditional GitHub Pull Request (PR) workflow for user contributions, which roughly follows these steps:

  • Create a personal fork of (unless you already have push permissions to an existing fork or the original repo)

  • Preferably: work on your contribution in a new feature branch

  • Push your feature branch to your fork and create a pull request

  • The pull request is the place for review, discussion and fine-tuning of your work

  • Once your pull request is in good shape it will be merged by a maintainer

Pre-commit for basic code quality checks

We started using the pre-commit tool for basic fine-tuning of code style and quality in new contributions. It’s currently not enforced, but enabling pre-commit is recommended and appreciated when contributing code.


Note that the whole repository does not fully follow all code styles rules at the moment. We’re just gradually introducing it, piggybacking on new contributions and commits.

Pre-commit set up

  • Install the general pre-commit command line tool:

    • The simplest option is to install it directly in the virtual environment you are using for openEO Python client development (e.g. pip install pre-commit).

    • You can also install it globally on your system (e.g. using pipx, conda, homebrew, …) so you can use it across different projects.

  • Install the project specific git hook scripts by running this in the root of your local git clone:

    pre-commit install

    This will automatically install additional scripts and tools in a sandbox to run the various checks defined in the project’s .pre-commit-config.yaml configuration file.

Pre-commit usage

When you commit new changes, the freshly installed pre-commit hook will now automatically run each of the configured linters/formatters/… Some of these just flag issues (e.g. invalid JSON files) while others even automatically fix problems (e.g. clean up excessive whitespace).

If there is some kind of violation, the commit will be blocked. Address these problems and try to commit again.


Some pre-commit tools directly edit your files (e.g. formatting tweaks) instead of just flagging issues. This might feel intrusive at first, but once you get the hang of it, it should allow to streamline your workflow.

In particular, it is recommended to use the staging feature of git to prepare your commit. Pre-commit’s proposed changes are not staged automatically, so you can more easily keep them separate and review.


You can temporarily disable pre-commit for these rare cases where you intentionally want to commit violating code style, e.g. through git commit command line option -n/--no-verify.

Creating a release

This section describes the procedure to create properly versioned releases of the openeo package that can be downloaded by end users (e.g. through pip from and depended on by other projects.

The releases will end up on:


  • You have permissions to push branches and tags and maintain releases on the openeo-python-client project on GitHub.

  • You have permissions to upload releases to the openeo project on

  • The Python virtual environment you work in has the latest versions of the twine package installed. If you plan to build the wheel yourself (instead of letting GitHub or Jenkins do this), you also need recent enough versions of the setuptools and wheel packages.

Important files

describes the metadata of the package, like package name openeo and version (which is extracted from openeo/


defines the version of the package. During general development, this version string should contain a pre-release segment (e.g. a1 for alpha releases, b1 for beta releases, etc) to avoid collision with final releases. For example:

__version__ = '0.8.0a1'

As discussed below, this pre-release suffix should only be removed during the release procedure and restored when bumping the version after the release procedure.

keeps track of important changes associated with each release. It follows the Keep a Changelog convention and should be properly updated with each bug fix, feature addition/removal, … under the Unreleased section during development.


These are the steps to create and publish a new release of the openeo package. To avoid the confusion with ad-hoc injection of some abstract version placeholder that has to be replaced properly, we will use a concrete version 0.8.0 in the examples below.

  1. Make sure you are working on latest master branch, without uncommitted changes and all tests are properly passing.

  2. Create release commit:

    1. Drop the pre-release suffix from the version string in openeo/ so that it just a “final” semantic versioning string, e.g. 0.8.0

    2. Update rename the “Unreleased” section title to contain version and date, e.g.:

      ## [0.8.0] - 2020-12-15

      remove empty subsections and start a new “Unreleased” section above it, like:

      ## [Unreleased]
      ### Added
      ### Changed
      ### Removed
      ### Fixed
    3. Commit these changes in git with a commit message like Release 0.8.0 and push to GitHub:

      git add openeo/
      git commit -m 'Release 0.8.0'
      git push origin master
  3. Optional, but recommended: wait for VITO Jenkins to build this updated master (trigger it manually if necessary), so that a build of a final, non-alpha release 0.8.0 is properly uploaded to VITO artifactory.

  4. Create release on PyPI:

    1. Obtain a wheel archive of the package, with one of these approaches:

      • Preferably, the path of least surprise: build wheel through GitHub Actions. Go to workflow “Build wheel”, manually trigger a build with “Run workflow” button, wait for it to finish successfully, download generated, and finally: unzip it to obtain openeo-0.8.0-py3-none-any.whl

      • Or, if you know what you are doing and you’re sure you have a clean local checkout, you can also build it locally:

        python bdist_wheel

        This should create dist/openeo-0.8.0-py3-none-any.whl

    2. Upload this wheel to PyPI:

      python -m twine upload openeo-0.8.0-py3-none-any.whl

      Check the release history on PyPI to verify the twine upload. Another way to verify that the freshly created release installs is using docker to do a quick install-and-burn, for example as follows (check the installed version in pip’s output):

      docker run --rm -it python python -m pip install --no-deps openeo
  5. Create a git version tag and push it to GitHub:

    git tag v0.8.0
    git push origin v0.8.0
  6. Create a release in GitHub: Go to, Enter v0.8.0 under “tag”, enter title: openEO Python Client v0.8.0, use the corresponding section as description and publish it (no need to attach binaries).

  7. Bump the version in openeo/, (usually the “minor” level) and append a pre-release “a1” suffix again, for example:

    __version__ = '0.9.0a1'

    Commit this (e.g. with message bump to 0.9.0a1) and push to GitHub.

  8. Update conda-forge package too (requires conda recipe maintainer role). Normally, the “regro-cf-autotick-bot” will create a pull request. If it builds fine, merge it. If not, fix the issue (typically in recipe/meta.yaml) and merge.

  9. Optionally: make a post about the new release on the openEO Platform Forum or the CDSE Forum.


The new release should now be available/listed at:

Here is a bash (subshell) oneliner to verify that the PyPI release works properly:

    cd /tmp &&\
    python -m venv venv-openeo &&\
    source venv-openeo/bin/activate &&\
    pip install -U openeo &&\
    python -c "import openeo;print(openeo);print(openeo.__version__)"

It tries to install the latest version of the openeo package in a temporary virtual env, import it and print the package version.

Development Installation on Windows

Normally you can install the client the same way on Windows as on Linux, like so:

pip install -e .[dev]

Alternative development installation

The standard pure-pip based installation should work with the most recent code. However, in the past we sometimes had issues with this procedure. Should you experience problems, consider using an alternative conda-based installation procedure:

  1. Create and activate a new conda environment for developing the openeo-python-client. For example:

    conda create -n openeopyclient
    conda activate openeopyclient
  2. In that conda environment, install only the dependencies of openeo via conda, but not the openeo package itself.

    # Install openeo dependencies (from the conda-forge channel)
    conda install --only-deps -c conda-forge openeo
  3. Do a pip install from the project root in editable mode (pip -e):

    pip install -e .[dev]

Update of generated files

Some parts of the openEO Python Client Library source code are generated/compiled from upstream sources (e.g. official openEO specifications). Because updates are not often required, it’s just a semi-manual procedure (to run from the project root):

# Update the sub-repositories (like git submodules, but optional)
python specs/

# Update `openeo/` from specifications in openeo-processes repository
python openeo/internal/processes/  specs/openeo-processes specs/openeo-processes/proposals --output openeo/

# Update the openEO process mapping documentation page
python docs/ > docs/process_mapping.rst