SafeEyes/safeeyes/PluginManager.py

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2017-10-07 15:10:31 +02:00
#!/usr/bin/env python
# Safe Eyes is a utility to remind you to take break frequently
# to protect your eyes from eye strain.
# Copyright (C) 2017 Gobinath
# 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/>.
"""
PluginManager loads all enabled plugins and call their lifecycle methods.
A plugin must have the following directory structure:
<plugin-id>
|- config.json
|- plugin.py
|- icon.png (Optional)
The plugin.py can have following methods but all are optional:
- description()
If a custom description has to be displayed, use this function
- on_init(context, safeeyes_config, plugin_config)
Initialize the plugin. Will be called after loading and after every changes in configuration
- on_start()
Executes when Safe Eyes is enabled
- on_stop()
Executes when Safe Eyes is disabled
- enable()
Executes once the plugin.py is loaded as a module
- disable()
Executes if the plugin is disabled at the runtime by the user
- on_exit()
Executes before Safe Eyes exits
"""
import importlib
import inspect
import logging
import os
import sys
from safeeyes import Utility
sys.path.append(os.path.abspath(Utility.SYSTEM_PLUGINS_DIR))
sys.path.append(os.path.abspath(Utility.USER_PLUGINS_DIR))
HORIZONTAL_LINE_LENGTH = 64
class PluginManager(object):
"""
Imports the Safe Eyes plugins and calls the methods defined in those plugins.
"""
def __init__(self, context, config):
logging.info('Load all the plugins')
self.__plugins = {}
self.__plugins_on_init = []
self.__plugins_on_start = []
self.__plugins_on_stop = []
self.__plugins_on_exit = []
self.__plugins_on_pre_break = []
self.__plugins_on_start_break = []
self.__plugins_on_stop_break = []
self.__plugins_on_countdown = []
self.__plugins_update_next_break = []
self.__widget_plugins = []
self.last_break = None
self.horizontal_line = '' * HORIZONTAL_LINE_LENGTH
def init(self, context, config):
"""
Initialize all the plugins with init(context, safeeyes_config, plugin_config) function.
"""
# Load the plugins
for plugin in config.get('plugins'):
try:
self.__load_plugin(plugin, context)
except BaseException:
logging.error('Error in loading the plugin: %s', plugin['id'])
continue
# Initialize the plugins
for plugin in self.__plugins_on_init:
plugin['module'].init(context, config, plugin['config'])
return True
def start(self):
"""
Execute the on_start() function of plugins.
"""
for plugin in self.__plugins_on_start:
plugin['module'].on_start()
return True
def stop(self):
"""
Execute the on_stop() function of plugins.
"""
for plugin in self.__plugins_on_stop:
plugin['module'].on_stop()
return True
def exit(self):
"""
Execute the on_exit() function of plugins.
"""
for plugin in self.__plugins_on_exit:
plugin['module'].on_exit()
return True
def pre_break(self, break_obj):
"""
Execute the on_pre_break(break_obj) function of plugins.
"""
for plugin in self.__plugins_on_pre_break:
if break_obj.plugin_enabled(plugin['id'], plugin['enabled']):
if plugin['module'].on_pre_break(break_obj):
return False
return True
def start_break(self, break_obj):
"""
Execute the start_break(break_obj) function of plugins.
"""
self.last_break = break_obj
for plugin in self.__plugins_on_start_break:
if break_obj.plugin_enabled(plugin['id'], plugin['enabled']):
if plugin['module'].on_start_break(break_obj):
return False
return True
def stop_break(self):
"""
Execute the stop_break() function of plugins.
"""
for plugin in self.__plugins_on_stop_break:
if self.last_break.plugin_enabled(plugin['id'], plugin['enabled']):
plugin['module'].on_stop_break()
def countdown(self, countdown, seconds):
"""
Execute the on_countdown(countdown, seconds) function of plugins.
"""
for plugin in self.__plugins_on_countdown:
if self.last_break.plugin_enabled(plugin['id'], plugin['enabled']):
plugin['module'].on_countdown(countdown, seconds)
def update_next_break(self, break_obj, break_time):
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"""
Execute the update_next_break(break_time) function of plugins.
"""
for plugin in self.__plugins_update_next_break:
plugin['module'].update_next_break(break_obj, break_time)
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return True
def get_break_screen_widgets(self, break_obj):
"""
Return the HTML widget generated by the plugins.
The widget is generated by calling the get_widget_title and get_widget_content functions of plugins.
"""
widget = ''
for plugin in self.__widget_plugins:
if break_obj.plugin_enabled(plugin['id'], plugin['enabled']):
try:
title = plugin['module'].get_widget_title(break_obj).upper().strip()
if title == '':
continue
content = plugin['module'].get_widget_content(break_obj)
if content == '':
continue
widget += '<b>{}</b>\n{}\n{}\n\n\n'.format(title, self.horizontal_line, content)
except BaseException:
continue
return widget.strip()
def __has_method(self, module, method_name, no_of_args=0):
"""
Check whether the given function is defined in the module or not.
"""
if hasattr(module, method_name):
if len(inspect.getargspec(getattr(module, method_name)).args) == no_of_args:
return True
return False
def __remove_if_exists(self, list_of_items, item):
"""
Remove the item from the list_of_items it it exists.
"""
if item in list_of_items:
list_of_items.remove(item)
def __load_plugin(self, plugin, context):
"""
Load the given plugin.
"""
plugin_enabled = plugin['enabled']
if plugin['id'] in self.__plugins and not plugin_enabled:
# A disabled plugin but that was loaded earlier
plugin_obj = self.__plugins[plugin['id']]
if plugin_obj['enabled']:
# Previously enabled but now disabled
plugin_obj['enabled'] = False
self.__remove_if_exists(self.__plugins_on_start, plugin_obj)
self.__remove_if_exists(self.__plugins_on_stop, plugin_obj)
self.__remove_if_exists(self.__plugins_on_exit, plugin_obj)
self.__remove_if_exists(self.__plugins_update_next_break, plugin_obj)
# Call the plugin.disable method if available
if self.__has_method(plugin_obj['module'], 'disable'):
plugin_obj['module'].disable()
logging.info("Successfully unloaded the plugin '%s'", plugin['id'])
if not plugin_obj['break_override_allowed']:
# Remaining methods also should be removed
self.__remove_if_exists(self.__plugins_on_init, plugin_obj)
self.__remove_if_exists(self.__plugins_on_pre_break, plugin_obj)
self.__remove_if_exists(self.__plugins_on_start_break, plugin_obj)
self.__remove_if_exists(self.__plugins_on_stop_break, plugin_obj)
self.__remove_if_exists(self.__plugins_on_countdown, plugin_obj)
self.__remove_if_exists(self.__widget_plugins, plugin_obj)
del self.__plugins[plugin['id']]
return
# Look for plugin.py
plugin_dir = None
if os.path.isfile(os.path.join(Utility.SYSTEM_PLUGINS_DIR, plugin['id'], 'plugin.py')):
plugin_dir = Utility.SYSTEM_PLUGINS_DIR
elif os.path.isfile(os.path.join(Utility.USER_PLUGINS_DIR, plugin['id'], 'plugin.py')):
plugin_dir = Utility.USER_PLUGINS_DIR
else:
logging.error('plugin.py not found for the plugin: %s', plugin['id'])
return
# Look for config.json
plugin_config_path = os.path.join(plugin_dir, plugin['id'], 'config.json')
if not os.path.isfile(plugin_config_path):
logging.error('config.json not found for the plugin: %s', plugin['id'])
return
plugin_config = Utility.load_json(plugin_config_path)
if plugin_config is None:
return
if (plugin_enabled or plugin_config.get('break_override_allowed', False)):
if plugin['id'] in self.__plugins:
# The plugin is already enabled or partially loaded due to break_override_allowed
# Use the existing plugin object
plugin_obj = self.__plugins[plugin['id']]
if plugin_obj['enabled']:
# Already loaded completely
return
# Plugin was partially loaded due to break_override_allowed
if plugin_enabled:
# Load the rest of the methods
plugin_obj['enabled'] = True
module = plugin_obj['module']
if self.__has_method(module, 'on_start'):
self.__plugins_on_start.append(plugin_obj)
if self.__has_method(module, 'on_stop'):
self.__plugins_on_stop.append(plugin_obj)
if self.__has_method(module, 'on_exit'):
self.__plugins_on_exit.append(plugin_obj)
if self.__has_method(module, 'update_next_break', 2):
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self.__plugins_update_next_break.append(plugin_obj)
else:
# This is the first time to load the plugin
# Check for dependencies
if Utility.check_plugin_dependencies(plugin_config):
return
# Load the plugin module
module = importlib.import_module((plugin['id'] + '.plugin'))
logging.info("Successfully loaded %s", str(module))
plugin_obj = {'id': plugin['id'], 'module': module, 'config': plugin.get('settings', {}), 'enabled': plugin_enabled, 'break_override_allowed': plugin_config.get('break_override_allowed', False)}
self.__plugins[plugin['id']] = plugin_obj
if self.__has_method(module, 'enable'):
module.enable()
if plugin_enabled:
if self.__has_method(module, 'on_start'):
self.__plugins_on_start.append(plugin_obj)
if self.__has_method(module, 'on_stop'):
self.__plugins_on_stop.append(plugin_obj)
if self.__has_method(module, 'on_exit'):
self.__plugins_on_exit.append(plugin_obj)
if self.__has_method(module, 'update_next_break', 2):
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self.__plugins_update_next_break.append(plugin_obj)
if self.__has_method(module, 'init', 3):
self.__plugins_on_init.append(plugin_obj)
if self.__has_method(module, 'on_pre_break', 1):
self.__plugins_on_pre_break.append(plugin_obj)
if self.__has_method(module, 'on_start_break', 1):
self.__plugins_on_start_break.append(plugin_obj)
if self.__has_method(module, 'on_stop_break', 0):
self.__plugins_on_stop_break.append(plugin_obj)
if self.__has_method(module, 'on_countdown', 2):
self.__plugins_on_countdown.append(plugin_obj)
if self.__has_method(module, 'get_widget_title', 1) and self.__has_method(module, 'get_widget_content', 1):
self.__widget_plugins.append(plugin_obj)