HackingHowto

2017-08-30T17:19:31Z

Chrysn: /* How to set up and maintain an environment for hacking with virtualenv */ when to enable plugins

= Hacking HOWTO =

== So you want to hack on GNU MediaGoblin? ==

First thing to do is check out the [http://mediagoblin.org/join/ web site] where we list all the project
infrastructure including:

* the IRC channel
* the mailing list
* the issue tracker

Additionally, we have information on how to get involved, who to talk
to, what needs to be worked on, and other things besides!

Second thing to do is take a look at [http://docs.mediagoblin.org/devel/codebase.html codebase chapter] where
we've started documenting how GNU MediaGoblin is built and how to add
new things. If you're planning on contributing in python, you should be aware
of [http://www.python.org/dev/peps/pep-0008/ PEP-8], the official Python style guide,
which we follow.

Third you'll need to get the requirements.

Fourth, you'll need to build a development environment. We use an
in-package checkout of virtualenv. This isn't the convenional way to
install virtualenv (normally you don't install virtualenv inside the
package itself) but we've found that it's significantly easier for
newcomers who aren't already familiar with virtualenv. If you *are*
already familiar with virtualenv, feel free to just install
mediagoblin in your own virtualenv setup... the necessary adjustments
should be obvious.

== Python 2 vs Python 3 ==

GNU MediaGoblin was originally written for Python 2, and much of the documentation on the wiki reflects that. However, since release v0.9.0, GNU MediaGoblin has attempted to provide support for Python 3. Unfortunately, not everything is working for Python 3 environments yet. Below is a non-exhaustive list of things that might not work if you set up GNU MediaGoblin a Python 3 environment.

=== Python 3 Issues ===

* fcgi - none of the flup packages ([https://pypi.python.org/pypi/flup flup], [https://pypi.python.org/pypi/flup-py3 flup-py3], [https://pypi.python.org/pypi/flup6 flup6]) appear to have proper support for Python 3.5.
* audio file spectrographs - [https://pypi.python.org/pypi/scikits.audiolab scikits.audiolab] [https://issues.mediagoblin.org/ticket/5467 appears to not work] in Python 3.
* Rackspace storage - the [https://pypi.python.org/pypi/python-cloudfiles cloudfiles] plugin may not work with Python 3.

== Getting requirements ==

First, you need to have the following installed before you can build
an environment for hacking on GNU MediaGoblin:

* Python 2.7 - http://www.python.org/ (You'll need Python as well as the dev files for building modules.)
* python-lxml - http://lxml.de/
* git - http://git-scm.com/
* SQLAlchemy 0.7.0 or higher - http://www.sqlalchemy.org/
* Pillow - http://python-pillow.org/
* virtualenv - http://www.virtualenv.org/
* Python GStreamer Bindings - http://gstreamer.freedesktop.org/modules/gst-python.html
* Node.js
* RabbitMQ server

=== GNU/Linux ===

==== Debian and derivatives ====

If you're running Debian GNU/Linux or a Debian-derived distribution
such as Debian, Mint, or [http://bugs.foocorp.net/issues/478 Ubuntu 10.10+], running the following should install these
requirements:

{{Cmd|sudo apt-get install git-core python python-dev python-lxml python-imaging python-virtualenv python-gst-1.0 libjpeg8-dev autoconf nodejs npm nodejs-legacy rabbitmq-server}}

==== Debian GNU/Linux jessie ====

{{Cmd|sudo apt-get install -y git-core python python-dev python-lxml python-imaging python-virtualenv libjpeg-dev autoconf nodejs npm nodejs-legacy python-gst-1.0 gstreamer1.0-plugins-base gstreamer1.0-plugins-bad gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly gstreamer1.0-libav python-numpy python-scipy libsndfile1-dev libasound2-dev libgstreamer-plugins-base1.0-dev rabbitmq-server}}

==== Fedora / RedHat(?) / CentOS ====

===== On Fedora: =====

{{Cmd|yum install python-paste-deploy python-paste-script git-core python python-devel python-lxml python-imaging python-virtualenv gstreamer-python nodejs}}

===== On CentOS7: =====

'''epel-release''' is the prerequisite for most of the below listed packages

{{Cmd|sudo yum install epel-release}}

{{Cmd|sudo yum update}}

{{Cmd|sudo yum install python-paste-deploy python-paste-script \ git-core python python-devel python-lxml python-imaging \ python-virtualenv npm automake nginx gcc}}

for video to work correctly (as per [https://mediagoblin.readthedocs.io/en/stable/siteadmin/media-types.html?highlight=video#video Enabling Media-Types Video]) you may choose to install AWEL 3rd party repo which provides with the latest gstreamer bindings and more:

* [http://awel.domblogger.net/7/media/x86_64/repoview/awel-media-release.html AWEL Repo],[https://media.librelamp.com/gst AWEL Gstreamer]

once installed:

{{Cmd|sudo yum install gstreamer1 gstreamer1-libav gstreamer1-plugins-base gstreamer1-plugins-base-tools gstreamer1-plugins-good gstreamer1-plugins-ugly gstreamer1-plugins-bad gstreamer1-python ffmpeg }}

==== openSUSE ====

This instructions might be incomplete.
Try on openSUSE 13.2 or 13.1:

{{Cmd|zypper install python-devel python-gstreamer-0_10 git-core python python-lxml python-Pillow python-virtualenv npm}}

==== ArchLinux / Parabola ====

The following command should work (<del>not tested on a new ArchLinux / Parabola install</del>. tested, it works):

{{Cmd|pacman -S git python2 python2-lxml python2-pillow python2-virtualenv gstreamer0.10-python}}

=== Mac OS X ===

==== Mac OS X Lion ====

Download the Newest Python.

Git is already installed.

* Note for Pillow and lxml, you can: pip install Pillow lxml

Python-lxml: http://muffinresearch.co.uk/archives/2009/03/05/install-lxml-on-osx/ with sudo

Pillow: http://pillow.readthedocs.org/en/3.0.x/installation.html#os-x-installation

Libjpeg & Libpng: http://ethan.tira-thompson.com/Mac_OS_X_Ports.html Combo Installer

==== Mac OS X Snow Leopard ====

# You will probably want to install MacPorts this will give you access to many free software packages in the same manner to apt-get and yum: https://www.macports.org/install.php
# Ensure you install Git and the command line tools: https://help.github.com/articles/set-up-git#platform-mac
# Once both of those are installed type this in your terminal and enter your password when prompted for it {{Cmd|sudo port install python27 py27-lxml py27-sqlalchemy py27-Pillow py27-virtualenv py27-gst-python py27-pastescript}}

=== Microsoft Windows ===

''Thanks wctype!''

==== Getting requirements ====

* Python 2.7 - [http://www.python.org/download/ Download] 
* git - [https://github.com/msysgit/git/downloads Download] 
* python-lxml - [http://pypi.python.org/pypi/lxml/2.3.5#downloads Tarball] [http://www.lfd.uci.edu/~gohlke/pythonlibs/#pil Binaries] 
* Pillow - [http://pillow.readthedocs.org/en/3.0.x/installation.html#windows-installation Download] 
* virtualenv - [http://pypi.python.org/pypi/virtualenvwrapper-win/1.0.8#downloads Download] 
* OSSBuild project provides reasonably up-to-date binaries of GStreamer - [https://code.google.com/p/ossbuild/downloads/list Download] 
* py-bcrypt - [https://bitbucket.org/alexandrul/py-bcrypt/downloads/ Download] 
* Node JS

----

'''You can help:'''

If you have instructions for other GNU/Linux distributions, Windows, or Mac OS X to set
up requirements, [http://mediagoblin.org/join/ let us know]!

== How to set up and maintain an environment for hacking with virtualenv ==

'''Requirements'''

No additional requirements.

'''Create a development environment'''

After installing the requirements, follow these steps:

* Clone the repository: {{Cmd|git clone <nowiki>git://git.savannah.gnu.org/mediagoblin.git</nowiki>}}
* Make the environment: {{Cmd|./bootstrap.sh && ./configure && make}}
* If you want to use audio or video, this is the time to add the appropriate plugins to <tt>mediagoblin.ini</tt>
* Init the database:
{{Cmd|./bin/gmg dbupdate}}

That's it!

If you want to make sure things are working, consider running the test suite:
{{Cmd|./runtests.sh}}

(If you have troubles in the remaining steps, consider try installing
virtualenv with one of the flags --setuptools, --distribute or possibly --no-site-packages. Additionally, if your system has python3.X as the default, you might need to do virtualenv --python=python2.7 or --python=python2.6)

If you have problems, please [http://mediagoblin.org/join/ let us know]!

== Updating an existing environment ==

'''Updating for dependency changes'''

While hacking on GNU MediaGoblin over time, you'll eventually have to
update your development environment because the dependencies have
changed.

To do that, run:

{{Cmd|./bin/python setup.py develop --upgrade && ./bin/gmg dbupdate}}

'''Updating for code changes'''

{{Cmd|git pull -u}}
{{Cmd|git submodule update}}

'''NOTE:''' MediaGoblin used to be hosted on gitorious.org, but that is moving to read-only mode, so we're now on Savannah. If you have an old checkout, please update it by running the following:

{{Cmd|git remote set-url origin git://git.savannah.gnu.org/mediagoblin.git}}

== Running the server ==

If you want to get things running quickly and without hassle, just
run:

{{Cmd|./lazyserver.sh}}

This will start up a python server where you can begin playing with
mediagoblin, listening on 127.0.0.1:6543. It will also run celery in "always eager" mode so you
don't have to start a separate process for it.

By default, the instance is not sending out confirmation mails. Instead they are redirected to the standard output (the console) of lazyserver.sh.

You can change this behavior setting <code>email_debug_mode</code> to <code>false</code> in mediagoblin.ini

This is fine in development, but if you want to actually run celery
separately for testing (or deployment purposes), you'll want to run
the server independently:

{{Cmd|./bin/paster serve paste.ini --reload}}

== Running celeryd ==

If you aren't using <tt>./lazyserver.sh</tt> or otherwise aren't running celery
in always eager mode, you'll need to do this if you want your media to
process and actually show up. It's probably a good idea in
development to have the web server (above) running in one terminal and
celeryd in another window.

Run:

{{Cmd|<nowiki>CELERY_CONFIG_MODULE=mediagoblin.init.celery.from_celery ./bin/celeryd</nowiki>}}

== Running the test suite ==

See also [[UnitTests]] and [[Manual Functional Testing]].

Run:

{{Cmd|./runtests.sh}}

== Running a shell ==

If you want a shell with your database pre-setup and an instantiated
application ready and at your fingertips ......

Run:

{{Cmd|./bin/gmg shell}}

== Troubleshooting ==

If you see a python error, search for the full line in [https://issues.mediagoblin.org/report trac] to find issues that mention the same . If it has not been fixed, you can update corresponding bug reports or open a new one.

For developers it is a special pleasure to test and apply user submitted patches. Here is a good minimal [https://issues.mediagoblin.org/timeline?from=2016-02-28T17%3A16%3A39-05%3A00&precision=second git workflow] as example.

== Wiping your user data ==

You can completely wipe all data from the instance by doing:

{{Cmd|rm -rf mediagoblin.db kombu.db celery.db user_dev; ./bin/gmg dbupdate}}

'''Note:'''

Unless you're doing development and working on and testing creating
a new instance, you will probably never have to do this.

== Quickstart for Django programmers ==

We're not using Django, but the codebase is very Django-like in its
structure.

* <tt>routing.py</tt> is like <tt>urls.py</tt> in Django
* <tt>models.py</tt> has SQLAlchemy ORM definitions
* <tt>views.py</tt> is where the views go

We're using SQLAlchemy, which is semi-similar to the Django ORM, but
not really because you can get a lot more fine-grained. The
[http://docs.sqlalchemy.org/en/latest/orm/tutorial.html SQLAlchemy ORM tutorial] is a great place to start.

'''YouCanHelp'''

If there are other things that you think would help orient someone
new to GNU MediaGoblin but coming from Django, let us know!

== Showing off your work with PageKite ==

If you're doing development with MediaGoblin, it's sometimes helpful to show off your work to gather feedback from other contributors. A number of the MediaGoblin developers use something called [http://pagekite.net PageKite], which is a fellow free software web service which makes temporarily showing off work on your machine easy. There's a [http://pagekite.net/wiki/Howto/UsePageKiteWithMediaGoblin/ tutorial on how to use PageKite and MediaGoblin together] available on the PageKite wiki.

If you are doing a lot of MediaGoblin development, the PageKite people have graciously offered us a good amount of bandwidth at no cost in an effort to help out fellow free software projects. If you've been making significant contributions, PM Chris Webber on freenode (who is paroneayea there) and ask if you can be added to our group plan.

== Bite-sized bugs to start with ==

Now you should visit our latest list of [http://issues.mediagoblin.org/query?status=!closed&keywords=~bitesized bite-sized issues] because squishing bugs is messy fun. If you're interested in other things to work on, or need help getting started on a bug, let us know on [http://mediagoblin.org/join/ the mailing list] or on the [http://mediagoblin.org/join/ IRC channel].

GNU MediaGoblin Wiki - User contributions [en]

HackingHowto