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.

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 :class:`can.BusABC`. See below 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.

About the BusABC class

Concrete implementations have to implement the following:

• :meth:`~can.BusABC.send` to send individual messages
• :meth:`~can.BusABC._recv_internal` to receive individual messages (see note below!)
• set the :attr:`~can.BusABC.channel_info` attribute to a string describing the underlying bus and/or channel

They might implement the following:

• :meth:`~can.BusABC.flush_tx_buffer` to allow discarding any messages yet to be sent
• :meth:`~can.BusABC.shutdown` to override how the bus should shut down
• :meth:`~can.BusABC._send_periodic_internal` to override the software based periodic sending and push it down to the kernel or hardware.
• :meth:`~can.BusABC._apply_filters` to apply efficient filters to lower level systems like the OS kernel or hardware.
• :meth:`~can.BusABC._detect_available_configs` to allow the interface to report which configurations are currently available for new connections.
• :meth:`~can.BusABC.state` property to allow reading and/or changing the bus state.

This is the entire ABC bus class with all internal methods:

.. autoclass:: can.BusABC
    :private-members:
    :special-members:
    :noindex:

Concrete instances are created by :class:`can.Bus`.

Code Structure

The modules in python-can are:

Creating a new Release

• 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.
• Create and upload the distribution: python setup.py sdist bdist_wheel.
• 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.