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# Developer’s Overview

## Contributing

Contribute to source code, documentation, examples and report issues: https://github.com/hardbyte/python-can

Note that the latest released version on PyPi may be significantly behind the `main` branch. Please open any feature requests against the `main` branch

There is also a python-can mailing list for development discussion.

Some more information about the internals of this library can be found in the chapter Internal API. There is also additional information on extending the `can.io` module.

## Pre-releases

The latest pre-release can be installed with:

    pip install --upgrade --pre python-can

## Building & Installing

The following assumes that the commands are executed from the root of the repository:

The project can be built with:

    pipx run build
    pipx run twine check dist/*

The project can be installed in editable mode with:

    pip install -e .

The unit tests can be run with:

    pipx run tox -e py

The documentation can be built with:

    pipx run tox -e docs

The linters can be run with:

    pip install -e .[lint]
    black --check can
    mypy can
    ruff check can
    pylint can/**.py can/io doc/conf.py examples/**.py can/interfaces/socketcan

## Creating a new interface/backend

These steps are a guideline on how to add a new backend to python-can.

- Create a module (either a `*.py` or an entire subdirectory depending on the complexity) inside `can.interfaces`

- Implement the central part of the backend: the bus class that extends `can.BusABC`. See Extending the BusABC class for more info on this one!

- Register your backend bus class in `BACKENDS` in the file `can.interfaces.__init__.py`.

- Add docs where appropriate. At a minimum add to `doc/interfaces.rst` and add a new interface specific document in `doc/interface/*`. It should document the supported platforms and also the hardware/software it requires. A small snippet of how to install the dependencies would also be useful to get people started without much friction.

- Also, don’t forget to document your classes, methods and function with docstrings.

- Add tests in `test/*` where appropriate. To get started, have a look at `back2back_test.py`: Simply add a test case like `BasicTestSocketCan` and some basic tests will be executed for the new interface.

Attention

We strongly recommend using the Plugin Interface to extend python-can. Publish a python package that contains your `can.BusABC` subclass and use it within the python-can API. We will mention your package inside this documentation and add it as an optional dependency.

## Code Structure

The modules in `python-can` are:

Module | Description
--- | ---
interfaces | Contains interface dependent code.
bus | Contains the interface independent Bus object.
message | Contains the interface independent Message object.
io | Contains a range of file readers and writers.
broadcastmanager | Contains interface independent broadcast manager code.

## Creating a new Release

- Release from the `main` branch (except for pre-releases).

- Check if any deprecations are pending.

- Run all tests and examples against available hardware.

- Update `CONTRIBUTORS.txt` with any new contributors.

- For larger changes update `doc/history.rst`.

- Sanity check that documentation has stayed inline with code.

- In a new virtual env check that the package can be installed with pip: `pip install python-can==X.Y.Z`.

- Create a new tag in the repository.

- Check the release on PyPi, Read the Docs and GitHub.

## Manual release steps (deprecated)

- Create a temporary virtual environment.

- Create a new tag in the repository. Use semantic versioning.

- Build with `pipx run build`

- Sign the packages with gpg `gpg --detach-sign -a dist/python_can-X.Y.Z-py3-none-any.whl`.

- Upload with twine `twine upload dist/python-can-X.Y.Z*`.