From: Elrond Date: Sat, 9 Mar 2013 13:02:01 +0000 (+0100) Subject: Revive old "Design Decisions". X-Git-Url: https://vcs.fsf.org/?a=commitdiff_plain;h=43a2f7fe79c78c387804eadf4be9e3e232a1e0df;p=mediagoblin.git Revive old "Design Decisions". This brings back the exact version that was removed in 65e7ce634cfecc87ed6f390f9ccf91be513d2eea. --- diff --git a/docs/source/devel/originaldesigndecisions.rst b/docs/source/devel/originaldesigndecisions.rst new file mode 100644 index 00000000..afa1e26b --- /dev/null +++ b/docs/source/devel/originaldesigndecisions.rst @@ -0,0 +1,329 @@ +.. _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 `_, 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. + + diff --git a/docs/source/index.rst b/docs/source/index.rst index 9124b1c1..0ddacb71 100644 --- a/docs/source/index.rst +++ b/docs/source/index.rst @@ -84,6 +84,7 @@ This chapter contains various information for developers. :maxdepth: 1 devel/codebase + devel/originaldesigndecisions Indices and tables