Always one in every bunch. :)
I hear what you're saying about the import errors. But does it really
help to allow work to get done before throwing the error? I would think
you'd want to know right up front if you don't have a driver loaded
rather then letting a program actually get started up and think you can
write data (think fat client app) only to get a connection exception.
But I, of course, could be very wrong about this. I am about many things...
Monty
Michael Bayer wrote:
>
> yeah i dont like setup.py develop either :)....but anyway, patch is
> good. one thing i have to nail down though is ticket #480. the
> main point of that ticket is to cleanly isolate ImportErrors of
> actual DBAPI modules apart from the containing dialect module
> itself. the dialects are catching all the DBAPI-related
> ImportErrors though so its not necessarily blocking this patch (its
> just they cant report them nicely).
>
>
> On Mar 26, 2007, at 1:34 PM, Monty Taylor wrote:
>
>> Michael Bayer wrote:
>>> i think using entry points to load in external database dialects is a
>>> great idea.
>>>
>>> though the current six core dialects i think i still want to load via
>>> __import__ though since im a big fan of running SA straight out of
>>> the source directory (and therefore thered be no entry points for
>>> those in that case).
>>>
>>> so probably a check via __import__('sqlalchemy.databases') first,
>>> then an entry point lookup. does that work ?
>> Here is a patch that implements use of entry points to load dialects.
>> The largest change is actually adding a get_dialect to replace the
>> functionality of get_module, since entry points really want to return
>> classes, and we only ever use the dialect class from the returned
>> module
>> anyway...
>>
>> This does not break code that I have that loads the mysql dialect, and
>> it does work with my new code that adds a new dialect - although I
>> suppose it's possible it could have broken something I didn't find.
>>
>> As a side note, I agree with Gaetan - you can run entry points and
>> stuff
>> out of the current directory, especially if you use setup.py
>> develop ...
>> but this code does the entry points second, after a check for the
>> module
>> the old way.
>>
>> Monty
>>
>>
>> === modified file 'lib/sqlalchemy/engine/strategies.py'
>> --- lib/sqlalchemy/engine/strategies.py 2007-02-25 22:44:52 +0000
>> +++ lib/sqlalchemy/engine/strategies.py 2007-03-26 17:03:13 +0000
>> @@ -42,16 +42,16 @@
>> u = url.make_url(name_or_url)
>>
>> # get module from sqlalchemy.databases
>> - module = u.get_module()
>> + dialect_cls = u.get_dialect()
>>
>> dialect_args = {}
>> # consume dialect arguments from kwargs
>> - for k in util.get_cls_kwargs(module.dialect):
>> + for k in util.get_cls_kwargs(dialect_cls):
>> if k in kwargs:
>> dialect_args[k] = kwargs.pop(k)
>>
>> # create dialect
>> - dialect = module.dialect(**dialect_args)
>> + dialect = dialect_cls(**dialect_args)
>>
>> # assemble connection arguments
>> (cargs, cparams) = dialect.create_connect_args(u)
>> @@ -71,7 +71,7 @@
>> raise exceptions.DBAPIError("Connection
>> failed", e)
>> creator = kwargs.pop('creator', connect)
>>
>> - poolclass = kwargs.pop('poolclass', getattr(module,
>> 'poolclass', poollib.QueuePool))
>> + poolclass = kwargs.pop('poolclass', getattr
>> (dialect_cls, 'poolclass', poollib.QueuePool))
>> pool_args = {}
>> # consume pool arguments from kwargs, translating a
>> few of the arguments
>> for k in util.get_cls_kwargs(poolclass):
>>
>> === modified file 'lib/sqlalchemy/engine/url.py'
>> --- lib/sqlalchemy/engine/url.py 2007-03-18 22:35:19 +0000
>> +++ lib/sqlalchemy/engine/url.py 2007-03-26 16:47:01 +0000
>> @@ -2,6 +2,7 @@
>> import cgi
>> import sys
>> import urllib
>> +import pkg_resources
>> from sqlalchemy import exceptions
>>
>> """Provide the URL object as well as the make_url parsing
>> function."""
>> @@ -69,6 +70,23 @@
>> s += '?' + "&".join(["%s=%s" % (k, self.query[k]) for
>> k in keys])
>> return s
>>
>> + def get_dialect(self):
>> + """Return the SQLAlchemy database dialect class
>> corresponding to this URL's driver name."""
>> + dialect=None
>> + try:
>> + module=getattr(__import__('sqlalchemy.databases.%s' %
>> self.drivername).databases, self.drivername)
>> + dialect=module.dialect
>> + except ImportError:
>> + if sys.exc_info()[2].tb_next is None:
>> + for res in pkg_resources.iter_entry_points
>> ('sqlalchemy.databases'):
>> + if res.name==self.drivername:
>> + dialect=res.load()
>> + else:
>> + raise
>> + if dialect is not None:
>> + return dialect
>> + raise exceptions.ArgumentError('unknown database %r' %
>> self.drivername)
>> +
>> def get_module(self):
>> """Return the SQLAlchemy database module corresponding to
>> this URL's driver name."""
>> try:
>>
>> === modified file 'setup.py'
>> --- setup.py 2007-03-23 21:33:24 +0000
>> +++ setup.py 2007-03-26 17:01:51 +0000
>> @@ -10,6 +10,10 @@
>> url = "http://www.sqlalchemy.org";,
>> packages = find_packages('lib'),
>> package_dir = {'':'lib'},
>> + entry_points = {
>> + 'sqlalchemy.databases': [
>> + '%s = sqlalchemy.databases.%s:dialect' % (f,f) for f in
>> + ['sqlite', 'postgres', 'mysql', 'oracle', 'mssql',
>> 'firebird']]},
>> license = "MIT License",
>> long_description = """\
>> SQLAlchemy is:
>>
>
>
> >
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