Contributing

On a Raspberry Pi

Make sure you have installed these packages via Debian package manager

sudo apt install python3-pytest mkdocs pre-commit python3-opencv

In another environment

Install the dependencies directly into a virtual environment using Python's built-in venv module:

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

Note that picamera2 - the library on which picamera-zero depends - is only installable on Linux.

Clone the repo

Make sure that you have a SSH key set up in GitHub first.

git clone git@github.com:RaspberryPiFoundation/picamera-zero.git

Documentation

The package is documented with mkdocs. From the directory with mkdocs.yml type

mkdocs serve

This will start the server. View the docs in a browser at http://127.0.0.1:8000

You can make changes to the docs in the .md files.

Testing

Navigate to the tests directory and run the pytest command:

pytest

You can write tests in the tests directory. Each test function, and each file needs to begin with the prefix test_

Build the package

From the main directory (with pyproject.toml) type:

sudo apt install python3-build
python -m build

The distribution will be created in the dist directory.

Continuous integration

There are two CI jobs executed on each PR. The lint job uses pre-commit to check for common errors and formatting, while the build job simply tries to build the package using the build module.

Pre-commit static checks

You may find it useful to set up pre-commit to run some static checks before each commit. Doing so can help catch common errors, and unify code style.

pre-commit should already be installed if you followed the installation instructions above - if not, install on a development pi with sudo apt install pre-commit. To set it up to run before every commit, execute pre-commit install. Once set up, pre-commit will check every file changed in a commit.

To make pre-commit check every file in the repository, execute pre-commit run --all-files. Alternatively, to skip verification, you can use the --no-verify option when committing: git commit --no-verify

At any time, you can uninstall pre-commit by running pre-commit uninstall.

Deployments

Deployments should use semantic versioning (https://semver.org/). The deployment workflow is triggered upon creation of a new Github release, and checks that the version specified in picamzero/__init__.py.__version__ matches the tag in the Github release. The package is then built using the build module before being deployed to TestPyPI and PyPI.