terminator/terminatorlib/plugin.py

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#!/usr/bin/python
# Terminator by Chris Jones <cmsj@tenshu.net>
# GPL v2 only
"""plugin.py - Base plugin system
Inspired by Armin Ronacher's post at
http://lucumr.pocoo.org/2006/7/3/python-plugin-system
Used with permission (the code in that post is to be
considered BSD licenced, per the authors wishes)
>>> registry = PluginRegistry()
>>> registry.instances
{}
>>> registry.load_plugins()
>>> plugins = registry.get_plugins_by_capability('test')
>>> len(plugins)
1
>>> plugins[0] #doctest: +ELLIPSIS
<testplugin.TestPlugin object at 0x...>
>>> registry.get_plugins_by_capability('this_should_not_ever_exist')
[]
>>> plugins[0].do_test()
'TestPluginWin'
"""
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import sys
import os
import borg
from util import dbg, err
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class Plugin(object):
"""Definition of our base plugin class"""
capabilities = None
def __init__(self):
"""Class initialiser."""
pass
class PluginRegistry(borg.Borg):
"""Definition of a class to store plugin instances"""
instances = None
path = None
done = None
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def __init__(self):
"""Class initialiser"""
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borg.Borg.__init__(self, self.__class__.__name__)
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self.prepare_attributes()
def prepare_attributes(self):
"""Prepare our attributes"""
if not self.instances:
self.instances = {}
if not self.path:
(head, tail) = os.path.split(borg.__file__)
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# FIXME: self.path should really be a list so we can have something
# in the users home directory
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self.path = os.path.join(head, 'plugins')
dbg('PluginRegistry::prepare_attributes: Plugin path: %s' %
self.path)
if not self.done:
self.done = False
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def load_plugins(self):
"""Load all plugins present in the plugins/ directory in our module"""
if self.done:
dbg('PluginRegistry::load_plugins: Already loaded')
return
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sys.path.insert(0, self.path)
files = os.listdir(self.path)
for plugin in files:
pluginpath = os.path.join(self.path, plugin)
if os.path.isfile(pluginpath) and plugin[-3:] == '.py':
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dbg('PluginRegistry::load_plugins: Importing plugin %s' %
plugin)
try:
module = __import__(plugin[:-3], None, None, [''])
for item in getattr(module, 'available'):
if item not in self.instances:
func = getattr(module, item)
self.instances[item] = func()
except Exception as e:
err('PluginRegistry::load_plugins: Importing plugin %s \
failed: %s' % (plugin, e))
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self.done = True
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def get_plugins_by_capability(self, capability):
"""Return a list of plugins with a particular capability"""
result = []
dbg('PluginRegistry::get_plugins_by_capability: searching %d plugins \
for %s' % (len(self.instances), capability))
for plugin in self.instances:
if capability in self.instances[plugin].capabilities:
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result.append(self.instances[plugin])
return result
def get_all_plugins(self):
"""Return all plugins"""
return(self.instances)
if __name__ == '__main__':
import doctest
sys.path.insert(0, 'plugins')
(failed, attempted) = doctest.testmod()
print "%d/%d tests failed" % (failed, attempted)