--- /dev/null
+.. _design-decisions-chapter:
+
+==================
+ Design Decisions
+==================
+
+.. contents:: Sections
+ :local:
+
+
+This chapter talks a bit about design decisions.
+
+
+Why GNU MediaGoblin?
+====================
+
+Chris and Will on "Why GNU MediaGoblin":
+
+ Chris came up with the name MediaGoblin. The name is pretty fun.
+ It merges the idea that this is a Media hosting project with
+ Goblin which sort of sounds like gobbling. Here's a piece of
+ software that gobbles up your media for all to see.
+
+ `According to Wikipedia <http://en.wikipedia.org/wiki/Goblin>`_, a
+ goblin is:
+
+ a legendary evil or mischievous illiterate creature, described
+ as grotesquely evil or evil-like phantom
+
+ So are we evil? No. Are we mischievous or illiterate? Not
+ really. So what kind of goblin are we thinking about? We're
+ thinking about these goblins:
+
+ .. figure:: goblin.png
+ :alt: Cute goblin with a beret.
+
+ *Figure 1: Cute goblin with a beret. llustrated by Chris
+ Webber*
+
+ .. figure:: snugglygoblin.png
+ :scale: 50%
+ :alt: Snuggly goblin with a beret.
+
+ *Figure 2: Snuggly goblin. Illustrated by Karen Rustad*
+
+ Those are pretty cute goblins. Those are the kinds of goblins
+ we're thinking about.
+
+ Chris started doing work on the project after thinking about it
+ for a year. Then, after talking with Matt and Rob, it became an
+ official GNU project. Thus we now call it GNU MediaGoblin.
+
+ That's a lot of letters, though, so in the interest of brevity and
+ facilitating easier casual conversation and balancing that with
+ what's important to us, we have the following rules:
+
+ 1. "GNU MediaGoblin" is the name we're going to use in all official
+ capacities: web site, documentation, press releases, ...
+
+ 2. In casual conversation, it's ok to use more casual names.
+
+ 3. If you're writing about the project, we ask that you call it GNU
+ MediaGoblin.
+
+ 4. If you don't like the name, we kindly ask you to take a deep
+ breath, think a happy thought about cute little goblins playing
+ on a playground and taking cute pictures of themselves, and let
+ it go. (Will added this one.)
+
+
+Why Python
+==========
+
+Chris Webber on "Why Python":
+
+ Because I know Python, love Python, am capable of actually making
+ this thing happen in Python (I've worked on a lot of large free
+ software web applications before in Python, including `Miro
+ Community`_, the `Miro Guide`_, a large portion of `Creative
+ Commons`_, and a whole bunch of things while working at `Imaginary
+ Landscape`_). Me starting a project like this makes sense if it's
+ done in Python.
+
+ You might say that PHP is way more deployable, that Rails has way
+ more cool developers riding around on fixie bikes---and all of
+ those things are true. But I know Python, like Python, and think
+ that Python is pretty great. I do think that deployment in Python
+ is not as good as with PHP, but I think the days of shared hosting
+ are (thankfully) coming to an end, and will probably be replaced
+ by cheap virtual machines spun up on the fly for people who want
+ that sort of stuff, and Python will be a huge part of that future,
+ maybe even more than PHP will. The deployment tools are getting
+ better. Maybe we can use something like Silver Lining. Maybe we
+ can just distribute as ``.debs`` or ``.rpms``. We'll figure it
+ out when we get there.
+
+ Regardless, if I'm starting this project, which I am, it's gonna
+ be in Python.
+
+.. _Miro Community: http://mirocommunity.org/
+.. _Miro Guide: http://miroguide.org/
+.. _Creative Commons: http://creativecommons.org/
+.. _Imaginary Landscape: http://www.imagescape.com/
+
+
+Why WSGI Minimalism
+===================
+
+Chris Webber on "Why WSGI Minimalism":
+
+ If you notice in the technology list I list a lot of components
+ that are very "django-like", but not actually `Django`_
+ components. What can I say, I really like a lot of the ideas in
+ Django! Which leads to the question: why not just use Django?
+
+ While I really like Django's ideas and a lot of its components, I
+ also feel that most of the best ideas in Django I want have been
+ implemented as good or even better outside of Django. I could
+ just use Django and replace the templating system with Jinja2, and
+ the form system with wtforms, and the database with MongoDB and
+ MongoKit, but at that point, how much of Django is really left?
+
+ I also am sometimes saddened and irritated by how coupled all of
+ Django's components are. Loosely coupled yes, but still coupled.
+ WSGI has done a good job of providing a base layer for running
+ applications on and if you know how to do it yourself [1]_, it's
+ not hard or many lines of code at all to bind them together
+ without any framework at all (not even say `Pylons`_, `Pyramid`_
+ or `Flask`_ which I think are still great projects, especially for
+ people who want this sort of thing but have no idea how to get
+ started). And even at this already really early stage of writing
+ MediaGoblin, that glue work is mostly done.
+
+ Not to say I don't think Django isn't great for a lot of things.
+ For a lot of stuff, it's still the best, but not for MediaGoblin,
+ I think.
+
+ One thing that Django does super well though is documentation. It
+ still has some faults, but even with those considered I can hardly
+ think of any other project in Python that has as nice of
+ documentation as Django. It may be worth learning some lessons on
+ documentation from Django [2]_, on that note.
+
+ I'd really like to have a good, thorough hacking-howto and
+ deployment-howto, especially in the former making some notes on
+ how to make it easier for Django hackers to get started.
+
+.. _Django: http://www.djangoproject.com/
+.. _Pylons: http://pylonshq.com/
+.. _Pyramid: http://docs.pylonsproject.org/projects/pyramid/dev/
+.. _Flask: http://flask.pocoo.org/
+
+.. [1] http://pythonpaste.org/webob/do-it-yourself.html
+.. [2] http://pycon.blip.tv/file/4881071/
+
+
+Why MongoDB
+===========
+
+Chris Webber on "Why MongoDB":
+
+ In case you were wondering, I am not a NOSQL fanboy, I do not go
+ around telling people that MongoDB is web scale. Actually my
+ choice for MongoDB isn't scalability, though scaling up really
+ nicely is a pretty good feature and sets us up well in case large
+ volume sites eventually do use MediaGoblin. But there's another
+ side of scalability, and that's scaling down, which is important
+ for federation, maybe even more important than scaling up in an
+ ideal universe where everyone ran servers out of their own
+ housing. As a memory-mapped database, MongoDB is pretty hungry,
+ so actually I spent a lot of time debating whether the inability
+ to scale down as nicely as something like SQL has with sqlite
+ meant that it was out.
+
+ But I decided in the end that I really want MongoDB, not for
+ scalability, but for flexibility. Schema evolution pains in SQL
+ are almost enough reason for me to want MongoDB, but not quite.
+ The real reason is because I want the ability to eventually handle
+ multiple media types through MediaGoblin, and also allow for
+ plugins, without the rigidity of tables making that difficult. In
+ other words, something like::
+
+ {"title": "Me talking until you are bored",
+ "description": "blah blah blah",
+ "media_type": "audio",
+ "media_data": {
+ "length": "2:30",
+ "codec": "OGG Vorbis"},
+ "plugin_data": {
+ "licensing": {
+ "license": "http://creativecommons.org/licenses/by-sa/3.0/"}}}
+
+
+ Being able to just dump media-specific information in a media_data
+ hashtable is pretty great, and even better is having a plugin
+ system where you can just let plugins have their own entire
+ key-value space cleanly inside the document that doesn't interfere
+ with anyone else's stuff. If we were to let plugins to deposit
+ their own information inside the database, either we'd let plugins
+ create their own tables which makes SQL migrations even harder
+ than they already are, or we'd probably end up creating a table
+ with a column for key, a column for value, and a column for type
+ in one huge table called "plugin_data" or something similar. (Yo
+ dawg, I heard you liked plugins, so I put a database in your
+ database so you can query while you query.) Gross.
+
+ I also don't want things to be too loose so that we forget or lose
+ the structure of things, and that's one reason why I want to use
+ MongoKit, because we can cleanly define a much structure as we
+ want and verify that documents match that structure generally
+ without adding too much bloat or overhead (MongoKit is a pretty
+ lightweight wrapper and doesn't inject extra MongoKit-specific
+ stuff into the database, which is nice and nicer than many other
+ ORMs in that way).
+
+
+Why Sphinx for documentation
+============================
+
+Will Kahn-Greene on "Why Sphinx":
+
+ `Sphinx`_ is a fantastic tool for organizing documentation for a
+ Python-based project that makes it pretty easy to write docs that
+ are readable in source form and can be "compiled" into HTML, LaTeX
+ and other formats.
+
+ There are other doc systems out there, but given that GNU
+ MediaGoblin is being written in Python and I've done a ton of
+ documentation using Sphinx, it makes sense to use Sphinx for now.
+
+.. _Sphinx: http://sphinx.pocoo.org/
+
+
+Why AGPLv3 and CC0?
+===================
+
+Chris, Brett, Will, Rob, Matt, et al curated into a story where
+everyone is the hero by Will on "Why AGPLv3 and CC0":
+
+ The `AGPL v3`_ preserves the freedoms guaranteed by the GPL v3 in
+ the context of software as a service. Using this license ensures
+ that users of the service have the ability to examine the source,
+ deploy their own instance, and implement their own version. This
+ is really important to us and a core mission component of this
+ project. Thus we decided that the software parts should be under
+ this license.
+
+ However, the project is made up of more than just software:
+ there's CSS, images, and other output-related things. We wanted
+ the templates/images/css side of the project all permissive and
+ permissive in the same absolutely permissive way. We're waiving
+ our copyrights to non-software things under the CC0 waiver.
+
+ That brings us to the templates where there's some code and some
+ output. The template engine we're using is called Jinja2. It
+ mixes HTML markup with Python code to render the output of the
+ software. We decided the templates are part of the output of the
+ software and not the software itself. We wanted the output of the
+ software to be licensed in a hassle-free way so that when someone
+ deploys their own GNU MediaGoblin instance with their own
+ templates, they don't have to deal with the copyleft aspects of
+ the AGPLv3 and we'd be fine with that because the changes they're
+ making are identity-related. So at first we decided to waive our
+ copyrights to the templates with a CC0 waiver and then add an
+ exception to the AGPLv3 for the software such that the templates
+ can make calls into the software and yet be a separately licensed
+ work. However, Brett brought up the question of whether this
+ allows some unscrupulous person to make changes to the software
+ through the templates in such a way that they're not bound by the
+ AGPLv3: i.e. a loophole. We thought about this loophole and
+ between this and the extra legalese involved in the exception to
+ the AGPLv3, we decided that it's just way simpler if the templates
+ were also licensed under the AGPLv3.
+
+ Then we have the licensing for the documentation. Given that the
+ documentation is tied to the software content-wise, we don't feel
+ like we have to worry about ensuring freedom of the documentation
+ or worry about attribution concerns. Thus we're waiving our
+ copyrights to the documentation under CC0 as well.
+
+ Lastly, we have branding. This covers logos and other things that
+ are distinctive to GNU MediaGoblin that we feel represents this
+ project. Since we don't currently have any branding, this is an
+ open issue, but we're thinking we'll go with a CC BY-SA license.
+
+ By licensing in this way, we make sure that users of the software
+ receive the freedoms that the AGPLv3 ensures regardless of what
+ fate befalls this project.
+
+ So to summarize:
+
+ * software (Python, JavaScript, HTML templates): licensed
+ under AGPLv3
+ * non-software things (CSS, images, video): copyrights waived
+ under CC0 because this is output of the software
+ * documentation: copyrights waived under CC0 because it's not part
+ of the software
+ * branding assets: we're kicking this can down the road, but
+ probably CC BY-SA
+
+ This is all codified in the ``COPYING`` file.
+
+.. _AGPL v3: http://www.gnu.org/licenses/agpl.html
+.. _CC0 v1: http://creativecommons.org/publicdomain/zero/1.0/
+
+
+Why (non-mandatory) copyright assignment?
+=========================================
+
+Chris Webber on "Why copyright assignment?":
+
+ GNU MediaGoblin is a GNU project with non-mandatory but heavily
+ encouraged copyright assignment to the FSF. Most, if not all, of
+ the core contributors to GNU MediaGoblin will have done a
+ copyright assignment, but unlike some other GNU projects, it isn't
+ required here. We think this is the best choice for GNU
+ MediaGoblin: it ensures that the Free Software Foundation may
+ protect the software by enforcing the AGPL if the FSF sees fit,
+ but it also means that we can immediately merge in changes from a
+ new contributor. It also means that some significant non-FSF
+ contributors might also be able to enforce the AGPL if seen fit.
+
+ Again, assignment is not mandatory, but it is heavily encouraged,
+ even incentivized: significant contributors who do a copyright
+ assignment to the FSF are eligible to have a unique goblin drawing
+ produced for them by the project's main founder, Christopher Allan
+ Webber. See :ref:`contributing-howto-chapter` for details.
+
+
projects / mediagoblin.git / commitdiff