platypush/platypush/context/__init__.py
2019-07-16 16:51:27 +02:00

135 lines
3.6 KiB
Python

import asyncio
import importlib
import logging
from threading import RLock
from ..config import Config
logger = logging.getLogger(__name__)
# Map: backend_name -> backend_instance
backends = {}
# Map: plugin_name -> plugin_instance
plugins = {}
# Map: plugin_name -> init_lock to make sure that a plugin isn't initialized
# multiple times
plugins_init_locks = {}
# Reference to the main application bus
main_bus = None
def register_backends(bus=None, global_scope=False, **kwargs):
""" Initialize the backend objects based on the configuration and returns
a name -> backend_instance map.
Params:
bus -- If specific (it usually should), the messages processed by the
backends will be posted on this bus.
kwargs -- Any additional key-value parameters required to initialize the backends
"""
global main_bus
if bus:
main_bus = bus
if global_scope:
global backends
else:
backends = {}
for (name, cfg) in Config.get_backends().items():
module = importlib.import_module('platypush.backend.' + name)
# e.g. backend.pushbullet main class: PushbulletBackend
cls_name = ''
for token in module.__name__.title().split('.')[2:]:
cls_name += token.title()
cls_name += 'Backend'
try:
b = getattr(module, cls_name)(bus=bus, **cfg, **kwargs)
backends[name] = b
except AttributeError as e:
logger.warning('No such class in {}: {}'.format(
module.__name__, cls_name))
raise RuntimeError(e)
return backends
def get_backend(name):
""" Returns the backend instance identified by name if it exists """
global backends
return backends.get(name)
def get_plugin(plugin_name, reload=False):
""" Registers a plugin instance by name if not registered already, or
returns the registered plugin instance"""
global plugins
global plugins_init_locks
if plugin_name not in plugins_init_locks:
plugins_init_locks[plugin_name] = RLock()
if plugin_name in plugins and not reload:
return plugins[plugin_name]
try:
plugin = importlib.import_module('platypush.plugins.' + plugin_name)
except ImportError as e:
logger.warning('No such plugin: {}'.format(plugin_name))
raise RuntimeError(e)
# e.g. plugins.music.mpd main class: MusicMpdPlugin
cls_name = ''
for token in plugin_name.split('.'):
cls_name += token.title()
cls_name += 'Plugin'
plugin_conf = Config.get_plugins()[plugin_name] \
if plugin_name in Config.get_plugins() else {}
if 'disabled' in plugin_conf:
if plugin_conf['disabled'] is True:
return None
del plugin_conf['disabled']
if 'enabled' in plugin_conf:
if plugin_conf['enabled'] is False:
return None
del plugin_conf['enabled']
try:
plugin_class = getattr(plugin, cls_name)
except AttributeError as e:
logger.warning('No such class in {}: {} [error: {}]'.format(plugin_name, cls_name, str(e)))
raise RuntimeError(e)
with plugins_init_locks[plugin_name]:
if plugins.get(plugin_name) and not reload:
return plugins[plugin_name]
plugins[plugin_name] = plugin_class(**plugin_conf)
return plugins[plugin_name]
def get_bus():
global main_bus
return main_bus
def get_or_create_event_loop():
try:
loop = asyncio.get_event_loop()
except RuntimeError:
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
return loop
# vim:sw=4:ts=4:et: