Server config file

[Bernhard Keller]

add a config file mediagoblin.globals to handle variables like PAGINATION_DEFAULT_PER_PAGE and ATOM_DEFAULT_NR_OF_UPDATED_ITEMS keeps mediagoblin.ini cleaner and allows for server independent settings

later users would be able to customise some of the parameters values that differ from the default config, would be stored as user dependent values in the database

[Bernhard Keller]

[https://gitorious.org/_{hunabku/mediagoblin/hunabkus-mediagoblin/commits/feature_global_config](https://gitorious.org/}hunabku/mediagoblin/hunabkus-mediagoblin/commits/feature_global_config)

first version

all variables in mediagoblin.globals get imported into the globals module missing variables get set to default values and written into the config file config file is created if it doesnt exist

[Christopher Allan Webber]

Hm. I've been thinking about this kind of user configuration for a while. I appreciate the approach you're taking here... I'm not 100% sure it's what we should do, but for what you're doing it does look good. I've had some thoughts that we should have an admin system where users are able to store their config stuff in the database for things like pagination numbers, etc. But obviously we don't have that yet, and we probably won't for a while. I'm thinking about this, anyway. I may want to do something simpler where we just store everything in the [app:mediagoblin] section in mediagoblin.globals.app_config and the whole config file in mediagoblin.globals.global_config. For now your solution might be the right way but I still need to think about it. :)

But anyway, along this form: let me suggest that instead of trying to do conversions between the different types yourself, use ConfigObj which does all that stuff for you: http://www.voidspace.org.uk/python/configobj.html

[Christopher Allan Webber]

As it turns out I just had a conversation with Ian Bicking in #pythonpaste

<ianbicking> paroneayea: hi
<paroneayea> ianbicking: yo.  So we're using paste deploy for
             http://mediagoblin.org/ and in a few parts of the program I have
             to open up the config file and read other sections out of it
<paroneayea> I think the documentation for this (maybe even the actual
             interfaces) could be a lot better
<paroneayea> so maybe I should write some documentation patches :)
<paroneayea> I partly wonder also if I'm doing things the right way at all.  I
             ended up both reading via paste.loadwsgi.appconfig and by faking
             reading the whole config file
             https://gitorious.org/mediagoblin/mediagoblin/blobs/master/mediagoblin/util.py#line354
<paroneayea> not in the same place though :)
<ianbicking> paroneayea: maybe in that case it makes sense not to use paste
             deploy for the entire app configuration
<ianbicking> e.g., fall back on a paste deploy config that looks like:
<ianbicking> [app:main] use = egg:MediaGoblin \n config = %(here)s/media.ini
<paroneayea> ianbicking: hm, okay :)
<paroneayea> maybe we can just use ConfigObj then also.
<paroneayea> ianbicking: thanks for the advice

... so I am warming up to this idea :)

[Christopher Allan Webber]

So I did some research into ConfigObj and it looks like it can handle everything I hoped, dreamed for and far, far more.

So the config setup we have currently is a mess. I have a vision for how to make it better, and I'm not sure if I'm going to do it myself or if I should pass it off to someone else. But here's some thoughts.

• Yes, we should have a separate file for configuration... that seems much clearer to me now.
• Looks like we can handle validation and even type conversion! from our config files via ConfigObj
• We should make sure we support %(here)s stuff, see the interpolation section

Probably things will look like:

[mediagoblin]
something = foo
something_else = 403094
some_directory %(here)s/path/to/something

# finally we can do *REAL* conversion of these values straight out of the config file!
# Amazing.
[celery] # maybe [mediagoblin.celery] ?
something = something
something_else = something

[some_plugin]
blah = foo

This could really simplify a heck of a lot of initialization code.

[Christopher Allan Webber]

Resources:

• http://www.voidspace.org.uk/python/configobj.html
• http://www.voidspace.org.uk/python/validate.html
• http://www.voidspace.org.uk/python/articles/configobj.shtml#validation

[Christopher Allan Webber]

Assigning to 0.0.3 and myself.

[Christopher Allan Webber]

The configobj loading stuff as well as validation, type conversion, interpolation stuff is handled now, with unit tests! I'm pretty happy about it.

But the application isn't using it. This ticket has grown a little bit in scope... I'm going to take the opportunity while factoring this into here to make instantiating the application a lot easier and cleaner.

[Christopher Allan Webber]

• There are now two config files, server.ini and mediagoblin.ini.
  • server.ini is for the paste deploy config
  • mediagoblin.ini is for the actual configuration of the mediagoblin application
• This means that the command to launch the server has been updated From the python point of view:
• Getting an application instance is as easy as initializing MediaGoblinApp(config_file_path)
• We now have validation and type conversion; see mediagoblin/config.py and mediagoblin/config_spec.ini
• Celery's defaults and etc also handled by the config system.
• The code for plenty of things is much, much cleaner now.

Anyway, done, closed, wooo!

[Christopher Allan Webber]

Also, special thanks for Bernard for proving that this was a good idea. :)

[Will Kahn-Greene]

The original url for this bug was ​http://bugs.foocorp.net/issues/351 .
Relations:
#98: precedes