# Developer’s Overview

## Contributing

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

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.

## Building & Installing

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

- The project can be built and installed with `python setup.py build` and `python setup.py install`.
- The unit tests can be run with `python setup.py test`. The tests can be run with `python2`, `python3`, `pypy` or `pypy3` to test with other python versions, if they are installed. Maybe, you need to execute `pip3 install python-can[test]` (or only `pip` for Python 2), if some dependencies are missing.
- The docs can be built with `sphinx-build doc/ doc/_build`. Appending `-n` to the command makes Sphinx complain about more subtle problems.

## 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 `can.interface.BACKENDS` and `can.interfaces.VALID_INTERFACES` in `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/*`.
- Update `doc/scripts.rst` accordingly.
- Add tests in `test/*` where appropriate.

## 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.
CAN | Legacy API. Deprecated.

## Process for creating a new Release

Note many of these steps are carried out by the CI system on creating a tag in git.

- Release from the `master` branch.
- Update the library version in `__init__.py` using semantic versioning.
- 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.
- Create a temporary virtual environment. Run `python setup.py install` and `python setup.py test`.
- Ensure the `setuptools` and `wheel` tools are up to date: `pip install -U setuptools wheel`.
- Create and upload the distribution: `python setup.py sdist bdist_wheel`.
- [Optionally] 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*`.
- 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.