Adding Ducksoup module

Signed-off-by: Ian Anderson <[email protected]>

.gitignore

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+build/
+dist/
+*.egg-info/
+*.pyc

MANIFEST.in

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+include README.textile

README.textile

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+h1. Ducksoup Module
+
+A ducktype plugin library for python. The module does a "ducktype" interface check on a "setuptools":http://peak.telecommunity.com/DevCenter/setuptools
+entry point module. If the module passes, it is listed as an available plugin.
+
+_*{color:red;}Requires "setuptools":http://peak.telecommunity.com/DevCenter/setuptools*_
+
+h2. Installing
+
+Run the following shell commands:
+
+<pre>
+git clone git://github.com/getfatday/ducksoup.git
+cd ducksoup
+./setup.py install
+</pre>
+
+h2. Usage
+
+Define a plugin interface and entry point for you application:
+
+<pre>
+# Define an interface.
+
+class ICommand(IPlugin):
+
+  name = ""
+  description = ""
+  def execute(*arg): pass
+
+# Register an entry point.
+
+class Command(plugin):
+    __entry_point__ = "ducksoup.plugin.commands"
+    __interface__ = ICommand
+</pre>
+
+Register an external module as a plugin.
+
+<pre>
+from setuptools import setup
+
+setup(
+  name="mycommands",
+  version="0.0.1",
+  description="""My Commands""",
+  entry_points="""
+  [ducksoup.plugin.commands]
+  mycommands.command = mycommands.command:Command
+  """
+)
+</pre>
+
+Search for available plugins:
+
+<pre>
+
+for entry in Command().entries:
+    print """Name: %s
+Description: %s
+""" % (entry.name, entry.description)    
+</pre>
+
+h2. Feedback
+
+Shoot me an email at "[email protected]":mailto:[email protected] with any feedback.

ducksoup/__init__.py

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+"""ducksoup
+
+A ducktype plugin library for python. The module does a "ducktype" interface check on a "setuptools":http://peak.telecommunity.com/DevCenter/setuptools
+entry point module. If the module passes, it is listed as an available plugin.
+"""
+
+__version__ = '0.0.1'
+__dist__ = 'git://github.com/getfatday/ducksoup.git'
+

ducksoup/interface.py

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+#!/usr/bin/env python
+# encoding: utf-8
+"""
+interface.py
+
+Created by Ian Anderson on 2009-07-08.
+
+Derived from:
+http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204349
+http://svn.pythonfr.org/public/pythonfr/plugin_framework/framework
+"""
+
+import inspect
+
+class interface_type(type):
+  """
+  Validates the presence of required attributes
+  """
+
+  def __new__(cls, classname, bases, classdict):
+    obj = type.__new__(cls, classname, bases, classdict)
+    interface = classdict.get('__implements__')
+
+    if interface:
+      defined = set(dir(obj))
+      required = set(dir(interface))
+      if not required.issubset(defined):
+        missing = list(required - defined)
+        error = "Not implemented methods from %s : %r"
+        raise KeyError, error % (interface.__name__, missing)
+
+    return obj
+
+
+class interface(object):
+  __metaclass__ = interface_type
+  __implements__ = None

ducksoup/plugin.py

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+#!/usr/bin/env python
+# encoding: utf-8
+"""
+plugin.py
+
+Created by Ian Anderson on 2009-07-08.
+"""
+
+from interface import interface
+from pkg_resources import iter_entry_points
+
+class IPlugin():
+  # Returns true if plugin is enabled
+  def enabled(self): pass
+
+class plugin_type(type):
+
+  def __init__(cls, classname, bases, classdict):
+    super(plugin_type, cls).__init__(classname, bases, classdict)
+    setattr(cls, '__entries__', None)
+    setattr(cls, '__invalid__', None)
+
+class plugin(object):
+
+  __metaclass__ = plugin_type
+  __entry_point__ = "ducksoup.plugin"
+  __interface__ = IPlugin
+
+  @classmethod
+  def enabled(cls):
+    return True
+
+  @property
+  def entries(self):
+    if self.__entries__ == None:
+      self.__getentries__()
+    return self.__entries__
+
+  @property
+  def invalid_entries(self):
+    if self.__invalid__ == None:
+      self.__getentries__()
+    return self.__invalid__
+
+  def __getentries__(self):
+    """Returns plugin classes avialable"""
+
+    self.__entries__ = []
+    self.__invalid__ = []
+
+    for e in iter_entry_points(group=self.__entry_point__):
+      cls = e.load()
+      defined = set(dir(cls))
+      required = set(dir(self.__interface__))
+      if not required.issubset(defined):
+        self.__invalid__.append(cls)
+        missing = list(required - defined)
+        error = "Plug-in '%s' missing implementations of '%s' required for '%s'"
+        print error % (cls.__name__, ", ".join(missing), self.__entry_point__)
+      else:
+        if cls.enabled():
+          self.__entries__.append(cls)

setup.py

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+#!/usr/bin/env python
+# encoding: utf-8
+
+"""
+Created by Ian Anderson on 2009-09-15.
+"""
+
+from setuptools import setup
+from ducksoup import __version__ as version
+from ducksoup import __doc__ as long_description
+
+setup(name = "ducksoup",
+    version = version,
+    description = "A ducktype plugin library for python",
+    author = "Ian Anderson",
+    author_email = "[email protected]",
+    url = "http://github.com/getfatday/ducksoup",
+    packages = ['ducksoup',],
+    long_description = long_description
+)