borg/docs/development.rst

.. include:: global.rst.inc
.. _development:

Development
===========

This chapter will get you started with |project_name|' development.

|project_name| is written in Python (with a little bit of Cython and C for
the performance critical parts).

Style guide
-----------

We generally follow `pep8
<https://www.python.org/dev/peps/pep-0008/>`_, with 120 columns
instead of 79. We do *not* use form-feed (``^L``) characters to
separate sections either. The `flake8
<https://flake8.readthedocs.org/>`_ commandline tool should be used to
check for style errors before sending pull requests.

Building a development environment
----------------------------------

First, just install borg into a virtual env as described before.

To install some additional packages needed for running the tests, activate your
virtual env and run::

  pip install -r requirements.d/development.txt


Running the tests
-----------------

The tests are in the borg/testsuite package.

To run all the tests, you need to have fakeroot installed. If you do not have
fakeroot, you still will be able to run most tests, just leave away the
`fakeroot -u` from the given command lines.

To run the test suite use the following command::

  fakeroot -u tox  # run all tests

Some more advanced examples::

  # verify a changed tox.ini (run this after any change to tox.ini):
  fakeroot -u tox --recreate

  fakeroot -u tox -e py32  # run all tests, but only on python 3.2

  fakeroot -u tox borg.testsuite.locking  # only run 1 test module

  fakeroot -u tox borg.testsuite.locking -- -k '"not Timer"'  # exclude some tests

  fakeroot -u tox borg.testsuite -- -v  # verbose py.test

Important notes:

- When using -- to give options to py.test, you MUST also give borg.testsuite[.module].


Building the docs with Sphinx
-----------------------------

The documentation (in reStructuredText format, .rst) is in docs/.

To build the html version of it, you need to have sphinx installed::

  pip3 install sphinx  # important: this will install sphinx with Python 3

Now run::

  cd docs/
  make html

Then point a web browser at docs/_build/html/index.html.

The website is updated automatically through Github web hooks on the
main repository.

Using Vagrant
-------------

We use Vagrant for the automated creation of testing environment and borgbackup
standalone binaries for various platforms.

For better security, there is no automatic sync in the VM to host direction.
The plugin `vagrant-scp` is useful to copy stuff from the VMs to the host.

Usage::

   To create and provision the VM:
     vagrant up OS
   To create an ssh session to the VM:
     vagrant ssh OS command
   To shut down the VM:
     vagrant halt OS
   To shut down and destroy the VM:
     vagrant destroy OS
   To copy files from the VM (in this case, the generated binary):
     vagrant scp OS:/vagrant/borg/borg/dist/borg .


Creating standalone binaries
----------------------------

Make sure you have everything built and installed (including llfuse and fuse).
When using the Vagrant VMs, pyinstaller will already be installed.

With virtual env activated::

  pip install pyinstaller>=3.0  # or git checkout master
  pyinstaller -F -n borg-PLATFORM --hidden-import=logging.config borg/__main__.py
  for file in dist/borg-*; do gpg --armor --detach-sign $file; done

If you encounter issues, see also our `Vagrantfile` for details.

.. note:: Standalone binaries built with pyinstaller are supposed to
          work on same OS, same architecture (x86 32bit, amd64 64bit)
          without external dependencies.


Creating a new release
----------------------

Checklist:

- make sure all issues for this milestone are closed or moved to the
  next milestone
- find and fix any low hanging fruit left on the issue tracker
- run tox on all supported platforms via vagrant, check for test failures
- check that Travis CI is also happy
- update ``CHANGES.rst``, based on ``git log $PREVIOUS_RELEASE..``
- check version number of upcoming release in ``CHANGES.rst``
- verify that ``MANIFEST.in`` and ``setup.py`` are complete
- tag the release::

    git tag -s -m "tagged/signed release X.Y.Z" X.Y.Z

- build fresh docs and update the web site with them
- create a release on PyPi::

    python setup.py register sdist upload --identity="Thomas Waldmann" --sign

- close release milestone on Github
- announce on:

 - `mailing list <mailto:borgbackup@librelist.org>`_
 - Twitter (follow @ThomasJWaldmann for these tweets)
 - `IRC channel <irc://irc.freenode.net/borgbackup>`_ (change ``/topic``)

- create a Github release, include:
  * standalone binaries (see above for how to create them)
  * a link to ``CHANGES.rst``