Hacking on Pyramid
==================

Here are some guidelines about hacking on Pyramid.

Using a Development Checkout
----------------------------

You'll have to create a development environment to hack on Pyramid, using a
Pyramid checkout.   You can either do this by hand or, if you have ``tox``
installed (it's on PyPI), you can (ab)use tox to get a working development
environment.  Each installation method is described below.

By Hand
+++++++

- Check out Pyramid from source::

   $ cd ~
   $ git clone git://github.com/Pylons/pyramid.git hack-on-pyramid
   $ cd hack-on-pyramid

- Create a virtualenv in which to install Pyramid::

   $ cd ~/hack-on-pyramid
   $ virtualenv -ppython2.7 env

  Note that very old versions of virtualenv (virtualenv versions below, say,
  1.10 or thereabouts) require you to pass a ``--no-site-packages`` flag to
  get a completely isolated environment.

  You can choose which Python version you want to use by passing a ``-p``
  flag to ``virtualenv``.  For example, ``virtualenv -ppython2.7``
  chooses the Python 2.7 interpreter to be installed.

  From here on in within these instructions, the ``~/hack-on-pyramid/env``
  virtual environment you created above will be referred to as ``$VENV``.
  To use the instructions in the steps that follow literally, use the
  ``export VENV=~/hack-on-pyramid/env`` command.

- Install ``setuptools-git`` into the virtualenv (for good measure, as we're
  using git to do version control)::

   $ $VENV/bin/easy_install setuptools-git

- Install Pyramid from the checkout into the virtualenv using ``setup.py
  dev``.  ``setup.py dev`` is an alias for "setup.py develop" which also
  installs testing requirements such as nose and coverage.  Running
  ``setup.py dev`` *must* be done while the current working directory is the
  ``pyramid`` checkout directory::

   $ cd ~/hack-on-pyramid
   $ $VENV/bin/python setup.py dev

- At that point, you should be able to create new Pyramid projects by using
  ``pcreate``::

  $ cd $VENV
  $ bin/pcreate -s starter starter

- And install those projects (also using ``setup.py develop``) into the
  virtualenv::

  $ cd $VENV/starter
  $ $VENV/bin/python setup.py develop

Using Tox
+++++++++

Alternatively, if you already have ``tox`` installed, there is an easier
way to get going.

- Create a new directory somewhere and ``cd`` to it::

   $ mkdir ~/hack-on-pyramid
   $ cd ~/hack-on-pyramid

- Check out a read-only copy of the Pyramid source::

   $ git clone git://github.com/Pylons/pyramid.git .

  (alternately, create a writeable fork on GitHub and check that out).

Since Pyramid is a framework and not an application, it can be
convenient to work against a sample application, preferably in its own
virtualenv. A quick way to achieve this is to (ab-)use ``tox``
(http://tox.readthedocs.org/en/latest/) with a custom configuration
file that's part of the checkout::

  tox -c hacking-tox.ini

This will create a python-2.7 based virtualenv named ``env27`` (Pyramid's
``.gitconfig` ignores all top-level folders that start with ``env`` specifically
for this use case) and inside that a simple pyramid application named
``hacking`` that you can then fire up like so::

  cd env27/hacking
  ../bin/pserve development.ini

Adding Features
---------------

In order to add a feature to Pyramid:

- The feature must be documented in both the API and narrative
  documentation (in ``docs/``).

- The feature must work fully on the following CPython versions: 2.6,
  2.7, 3.2, and 3.3 on both UNIX and Windows.

- The feature must work on the latest version of PyPy.

- The feature must not cause installation or runtime failure on App Engine.
  If it doesn't cause installation or runtime failure, but doesn't actually
  *work* on these platforms, that caveat should be spelled out in the
  documentation.

- The feature must not depend on any particular persistence layer
  (filesystem, SQL, etc).

- The feature must not add unnecessary dependencies (where
  "unnecessary" is of course subjective, but new dependencies should
  be discussed).

The above requirements are relaxed for scaffolding dependencies.  If a
scaffold has an install-time dependency on something that doesn't work on a
particular platform, that caveat should be spelled out clearly in *its*
documentation (within its ``docs/`` directory).

Coding Style
------------

- PEP8 compliance.  Whitespace rules are relaxed: not necessary to put
  2 newlines between classes.  But 80-column lines, in particular, are
  mandatory.  See
  http://docs.pylonsproject.org/en/latest/community/codestyle.html for more
  information.

- Please do not remove trailing whitespace.  Configure your editor to reduce
  diff noise. See https://github.com/Pylons/pyramid/issues/788 for more.

Running Tests
--------------

- To run all tests for Pyramid on a single Python version, run ``nosetests``
  from your development virtualenv (See *Using a Development Checkout* above).

- To run individual tests (i.e. during development) you can use a regular
  expression with the ``-t`` parameter courtesy of the `nose-selecttests
  <https://pypi.python.org/pypi/nose-selecttests/>`_ plugin that's been
  installed (along with nose itself) via ``python setup.py dev``. The
  easiest usage is to simply provide the verbatim name of the test you're
  working on.

- To run the full set of Pyramid tests on all platforms, install ``tox``
  (http://codespeak.net/~hpk/tox/) into a system Python.  The ``tox`` console
  script will be installed into the scripts location for that Python.  While
  ``cd``'ed to the Pyramid checkout root directory (it contains ``tox.ini``),
  invoke the ``tox`` console script.  This will read the ``tox.ini`` file and
  execute the tests on multiple Python versions and platforms; while it runs,
  it creates a virtualenv for each version/platform combination.  For
  example::

   $ sudo /usr/bin/easy_install tox
   $ cd ~/hack-on-pyramid/
   $ /usr/bin/tox

- The tests can also be run using ``pytest`` (http://pytest.org/).  This is
  intended as a convenience for people who are more used or fond of ``pytest``.
  Run the tests like so::

   $ $VENV/bin/easy_install pytest
   $ py.test --strict pyramid/

Test Coverage
-------------

- The codebase *must* have 100% test statement coverage after each commit.
  You can test coverage via ``tox -e coverage``, or alternately by installing
  ``nose`` and ``coverage`` into your virtualenv (easiest via ``setup.py
  dev``) , and running ``setup.py nosetests --with-coverage``.

Documentation Coverage and Building HTML Documentation
------------------------------------------------------

If you fix a bug, and the bug requires an API or behavior modification, all
documentation in this package which references that API or behavior must
change to reflect the bug fix, ideally in the same commit that fixes the bug
or adds the feature.

To build and review docs (where ``$VENV`` refers to the virtualenv you're
using to develop Pyramid):

1. After following the steps above in "Using a Development Checkout", cause
   Sphinx and all development requirements to be installed in your
   virtualenv::

     $ cd ~/hack-on-pyramid
     $ $VENV/bin/python setup.py docs

2. Update all git submodules from the top-level of your Pyramid checkout, like
   so::

     $ git submodule update --init --recursive

   This will checkout theme subrepositories and prevent error conditions when
   HTML docs are generated.

3. cd to the ``docs`` directory within your Pyramid checkout and execute
   the ``make`` command with some flags::

     $ cd ~/hack-on-pyramid/pyramid/docs
     $ make clean html SPHINXBUILD=$VENV/bin/sphinx-build

   The ``SPHINXBUILD=...`` argument tells Sphinx to use the virtualenv Python,
   which will have both Sphinx and Pyramid (for API documentation generation)
   installed.

4. Open the ``docs/_build/html/index.html`` file to see the resulting HTML
   rendering.

Change Log
----------

- Feature additions and bugfixes must be added to the ``CHANGES.txt``
  file in the prevailing style.  Changelog entries should be long and
  descriptive, not cryptic.  Other developers should be able to know
  what your changelog entry means.


