Source code for lib_openmolar.common.qt4.plugin_tools.plugin_handler
#! /usr/bin/env python
# -*- coding: utf-8 -*-
###############################################################################
## ##
## Copyright 2010, Neil Wallace <rowinggolfer@googlemail.com> ##
## ##
## This program is free software: you can redistribute it and/or modify ##
## it under the terms of the GNU General Public License as published by ##
## the Free Software Foundation, either version 3 of the License, or ##
## (at your option) any later version. ##
## ##
## This program is distributed in the hope that it will be useful, ##
## but WITHOUT ANY WARRANTY; without even the implied warranty of ##
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ##
## GNU General Public License for more details. ##
## ##
## You should have received a copy of the GNU General Public License ##
## along with this program. If not, see <http://www.gnu.org/licenses/>. ##
## ##
###############################################################################
import inspect
import logging
import os
import sys
import zipfile
import zipimport
from lib_openmolar.common.qt4.plugin_tools import Plugin
from PyQt4.QtCore import QResource, QString
[docs]class PluginHandler(object):
'''
A class to verify and install plugins
'''
#: locations of directories where plugins reside
PLUGIN_DIRS = []
#: locations of directories where naked plugins reside
NAKED_PLUGIN_DIRS = []
#:
ACTIVE_PLUGINS = set([])
_plugins = []
_fee_scales = []
[docs] def get_pluggable_classes(self, module, target=None):
'''
Args:
module (module object)
generates a list of all classes which are subclassed
from lib_openmolar.client.Plugin in the module "module"
'''
for name in dir(module):
obj = getattr(module, name)
## check is this object is a class.. and that it inherits
## from Plugin.. (but is not the Plugin base class itself!)
## hence issubclass wouldn't work
if inspect.isclass(obj) and Plugin in obj.mro()[1:]:
try:
LOGGER.debug("initiating plugin object %s"% obj)
klass = obj()
except Exception: # shouldn't happen!!
LOGGER.exception(
"Unable to instantiate Plugin %s from %s"% (obj, module))
continue
if target is None or klass.TARGET == target:
yield klass
else:
LOGGER.error("Plugin %s has target '%s' ignoring"% (
klass.name, klass.TARGET))
[docs] def get_modules(self, plugin_dir):
'''
finds all modules in plugin_dir
'''
sys.path.insert(0, str(plugin_dir))
for file_ in os.listdir(str(plugin_dir)):
full_path = os.path.join(str(plugin_dir), file_)
if file_.endswith(".py"):
LOGGER.debug("found module '%s'"% full_path)
if plugin_dir in self.NAKED_PLUGIN_DIRS:
LOGGER.info("NAKED PLUGIN FOUND '%s'"% full_path)
module = file_.replace('.py','')
mod = __import__(module)
yield mod
else:
LOGGER.info(
'IGNORING because %s is not a known store for naked plugins'%
plugin_dir)
elif zipfile.is_zipfile(full_path):
LOGGER.info("POSSIBLE PLUGIN FOUND '%s'"% full_path)
module = file_.replace('.zip','')
try:
z = zipimport.zipimporter(full_path)
mod = z.load_module(module)
yield mod
except (zipimport.ZipImportError, zipfile.BadZipfile) as e:
LOGGER.exception ("incompatible plugin '%s'"% full_path)
[docs] def get_plugins(self, plugin_dir, target=None):
'''
peruses a directory and finds all plugins
'''
for mod in self.get_modules(plugin_dir):
plugins = self.get_pluggable_classes(mod, target)
for plugin in plugins:
plugin.set_unique_id(QString(
"%s:%s"% (mod.__name__, os.path.abspath(str(plugin_dir)))))
self._plugins.append(plugin)
[docs] def load_plugins(self, target=None):
'''
this function is called by the client application to load plugins
'''
LOGGER.info ("loading plugins...")
for plugin_dir in self.PLUGIN_DIRS:
LOGGER.info ("="*80)
LOGGER.info ("looking for plugins in directory %s"% plugin_dir)
LOGGER.info ("="*80)
try:
self.get_plugins(plugin_dir, target)
except Exception as e:
LOGGER.exception ("Exception loading plugin")
LOGGER.info("%d plugin(s) loaded"% len(self.plugins))
[docs] def activate_plugins(self):
'''
iterates over the loaded plugins and activates them.
'''
LOGGER.info ("="*80)
LOGGER.info("Activating plugins")
LOGGER.info ("="*80)
i = 0
for plugin in self.plugins:
if plugin.unique_id in self.ACTIVE_PLUGINS:
self.activate_plugin(plugin)
i += 1
else:
LOGGER.debug(".. NOT ACTIVATING %s"% plugin.unique_id)
LOGGER.info("%d plugin(s) activated"% i)
[docs] def de_activate_plugins(self):
'''
iterates over the activated plugins and de-activates them.
'''
LOGGER.info ("="*80)
LOGGER.info("De-Activating plugins")
LOGGER.info ("="*80)
i = 0
for plugin in self.plugins:
if plugin.is_active:
self.deactivate_plugin(plugin)
i += 1
LOGGER.info("%d plugin(s) de-activated"% i)
[docs] def activate_plugin(self, plugin):
LOGGER.info("..Activating %s '%s'"% (plugin.__module__, plugin.name))
try:
if plugin.TYPE == plugin.FEE_SCALE:
self.install_fee_scale(plugin)
LOGGER.debug("setting up plugin %s"% plugin)
plugin.setup_plugin()
plugin.is_active = True
except Exception, e:
LOGGER.exception(
"Exception during plugin.setup_plugin '%s'"% plugin.name)
self.ACTIVE_PLUGINS.add(plugin.unique_id)
[docs] def deactivate_plugin(self, plugin):
LOGGER.info("..Deactivating %s '%s'"% (plugin.__module__, plugin.name))
if plugin.TYPE == plugin.FEE_SCALE:
self.remove_fee_scale(plugin)
try:
LOGGER.debug("calling teardoown plugin %s"% plugin)
plugin.tear_down()
except Exception, e:
LOGGER.exception(
"Exception during plugin.teardown '%s'"% plugin.name)
self.ACTIVE_PLUGINS.remove(plugin.unique_id)
plugin.is_active = False
@property
[docs] def install_fee_scale(self, fee_scale):
'''
installs a fee_scale (of type BasePlugin)
'''
LOGGER.info ("installing fee_scale %s"% fee_scale)
self._fee_scales.append(fee_scale)
[docs] def remove_fee_scale(self, fee_scale):
'''
removes a fee_scale (of type BasePlugin)
'''
LOGGER.info ("removing fee_scale %s"% fee_scale)
self._fee_scales.remove(fee_scale)
@property
[docs] def fee_scales(self):
'''
a list of all fee_scales installed (fee_scale = a type of BasePlugin)
'''
return sorted(self._fee_scales)
if __name__ == "__main__":
import lib_openmolar.client
logging.basicConfig(level = logging.DEBUG)
ph = PluginHandler()
ph.PLUGIN_DIRS = [
"/home/neil/openmolar/hg_openmolar/plugins/src/import_om1",
#"/home/neil/openmolar/hg_openmolar/plugins/src"
]
ph.NAKED_PLUGIN_DIRS = [
"/home/neil/openmolar/hg_openmolar/plugins/src/import_om1",
]
ph.ACTIVE_PLUGINS = set([QString(
"import_om1_plugin:/home/neil/openmolar/hg_openmolar/plugins/src/import_om1"
)])
ph.load_plugins("admin")
ph.activate_plugins()
ph.de_activate_plugins()
