~allenap/maas/docs-and-man-bug-975454

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Hacking MaaS

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Coding style

============

MaaS follows the `Launchpad Python Style Guide`_, except where it gets

Launchpad specific, and where it talks about `method naming`_. MaaS

instead adopts `PEP-8`_ naming in all cases, so method names should

usually use the ``lowercase_with_underscores`` form.

.. _Launchpad Python Style Guide:

  https://dev.launchpad.net/PythonStyleGuide

.. _method naming:

  https://dev.launchpad.net/PythonStyleGuide#Naming

.. _PEP-8:

  http://www.python.org/dev/peps/pep-0008/

Prerequisites

=============

You will need to manually install Postgres 9.1, RabbitMQ, python-dev and make::

    $ sudo apt-get install postgresql-9.1 rabbitmq-server python-dev make

Also, you might want to install Bazaar (bzr) to grab the source code directly

from Launchpad::

    $ sudo apt-get install bzr

This is the list of runtime dependencies that you'll need to install::

    $ sudo apt-get install python-django python-django-piston \

        python-django-south python-twisted python-txamqp python-amqplib \

        python-formencode python-oauth python-oops python-oops-datedir-repo \

        python-twisted python-oops-wsgi python-oops-twisted \

        python-psycopg2 python-yaml

Additionally, you need to install the following python libraries

for development convenience::

    $ sudo apt-get install python-sphinx python-lxml

If you intend to run the test suite, you also need xvfb and firefox::

    $ sudo apt-get install xvfb firefox

All other development dependencies are pulled automatically from `PyPI`_

when buildout runs.

.. _PyPI:

  http://pypi.python.org/

First time using buildout?

==========================

Buildout is used to develop MaaS. Buildout, if configured so, can

cache downloaded files and built eggs. If you've not already done

something similar, the following snippet will massively improve build

times::

    [buildout]

    download-cache = /home/<your-user-name>/.buildout/cache

    eggs-directory = /home/<your-user-name>/.buildout/eggs

Put this in ``~/.buildout/default.cfg`` and create the ``cache``

directory::

    $ mkdir /home/<your-user-name>/.buildout/cache

The ``eggs`` directory will be created automatically.

Getting the latest version of the code

======================================

You can grab the code manually from Launchpad but Bazaar makes it easy to fetch

the last version of the code. Go into the directory where you want the code

to reside and run::

    $ bzr branch lp:maas maas && cd maas

Development MaaS server setup

=============================

Access to the database is configured in ``src/maas/development.py``.

The ``Makefile`` or the test suite sets up a development database

cluster inside your branch. It lives in the ``db`` directory, which

gets created on demand. You'll want to shut it down before deleting a

branch; see below.

First, set up the project. This fetches all the required dependencies

and sets up some useful commands in ``bin/``::

    $ make

Create the database cluster and initialize the development database::

    $ make syncdb

Optionally, populate your database with the sample data::

    $ make sampledata

Install Cobbler, and import at least one distro and profile::

    $ sudo apt-get install apache2 cobbler

    $ sudo cobbler-ubuntu-import precise-i386  # For example.

Add yourself as a user in Cobbler. For convenience, give yourself the

password ``test``::

    $ sudo htdigest /etc/cobbler/users.digest Cobbler $USER

Alternatively, if you're not interested in the Provisioning Server or

Cobbler, set ``PSERV_URL`` to ``None`` in one of ``maas``'s settings

files (typically ``src/maas/demo.py``), and a fake Provisioning Server

will be used instead.

Run the development webserver::

    $ make run

Point your browser to http://localhost:8000/

If you've populated your instance with the sample data, you can login as a

simple user using the test account (username: 'test', password: 'test') or the

admin account (username: 'admin', password: 'test').

To shut down the database cluster and clean up all other generated files in

your branch::

    $ make distclean

Adding new dependencies

=======================

Since MaaS is distributed mainly as Ubuntu package, all runtime dependencies

should be packaged and we should develop with the packaged version if

possible. You'll need to add the dependency to the

``allowed-eggs-from-site-packages`` option in the ``buildout.cfg`` file. You

also need to add it to setup.py (And don't forget to add the version to

``versions.cfg`` as we run with ``allowed-picked-version`` set to false.)

If it is a development-only dependency (i.e. only needed for the test suite, or

for developers' convenience), simply running ``buildout`` like this will make

the necessary updates to ``versions.cfg``::

    $ ./bin/buildout -v buildout:allow-picked-versions=true

Adding new source files

=======================

When creating a new source file, a Python module or test for example,

always start with the appropriate template from the ``templates``

directory.

Documentation

=============

Use `reST`_ with the `convention for headings as used in the Python

documentation`_.

.. _reST: http://sphinx.pocoo.org/rest.html

.. _convention for headings as used in the Python documentation:

  http://sphinx.pocoo.org/rest.html#sections