178c417fb0
* component registry shutdown() now cleans up the component list this ensures that no old components are left when running unit tests. * Added class BaseTestCase that all tests that create components should inherit from. It verifies the compoent list before and after the tests are run.
431 lines
14 KiB
Python
431 lines
14 KiB
Python
# -*- coding: utf-8 -*-
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#
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# Copyright (C) 2007-2010 Andrew Resch <andrewresch@gmail.com>
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#
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# This file is part of Deluge and is licensed under GNU General Public License 3.0, or later, with
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# the additional special exception to link portions of this program with the OpenSSL library.
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# See LICENSE for more details.
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#
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import logging
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from collections import defaultdict
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from twisted.internet.defer import DeferredList, fail, maybeDeferred, succeed
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from twisted.internet.task import LoopingCall
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log = logging.getLogger(__name__)
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class ComponentAlreadyRegistered(Exception):
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pass
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class Component(object):
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"""
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Component objects are singletons managed by the :class:`ComponentRegistry`.
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When a new Component object is instantiated, it will be automatically
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registered with the :class:`ComponentRegistry`.
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The ComponentRegistry has the ability to start, stop, pause and shutdown the
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components registered with it.
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**Events:**
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**start()** - This method is called when the client has connected to a
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Deluge core.
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**stop()** - This method is called when the client has disconnected from a
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Deluge core.
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**update()** - This method is called every 1 second by default while the
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Componented is in a *Started* state. The interval can be
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specified during instantiation. The update() timer can be
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paused by instructing the :class:`ComponentRegistry` to pause
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this Component.
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**shutdown()** - This method is called when the client is exiting. If the
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Component is in a "Started" state when this is called, a
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call to stop() will be issued prior to shutdown().
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**States:**
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A Component can be in one of these 5 states.
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**Started** - The Component has been started by the :class:`ComponentRegistry`
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and will have it's update timer started.
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**Starting** - The Component has had it's start method called, but it hasn't
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fully started yet.
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**Stopped** - The Component has either been stopped or has yet to be started.
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**Stopping** - The Component has had it's stop method called, but it hasn't
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fully stopped yet.
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**Paused** - The Component has had it's update timer stopped, but will
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still be considered in a Started state.
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"""
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def __init__(self, name, interval=1, depend=None):
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self._component_name = name
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self._component_interval = interval
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self._component_depend = depend
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self._component_state = "Stopped"
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self._component_timer = None
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self._component_starting_deferred = None
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self._component_stopping_deferred = None
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_ComponentRegistry.register(self)
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def __del__(self):
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if _ComponentRegistry:
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_ComponentRegistry.deregister(self)
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def _component_start_timer(self):
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if hasattr(self, "update"):
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self._component_timer = LoopingCall(self.update)
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self._component_timer.start(self._component_interval)
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def _component_start(self):
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def on_start(result):
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self._component_state = "Started"
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self._component_starting_deferred = None
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self._component_start_timer()
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return True
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def on_start_fail(result):
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self._component_state = "Stopped"
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self._component_starting_deferred = None
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log.error(result)
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return result
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if self._component_state == "Stopped":
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if hasattr(self, "start"):
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self._component_state = "Starting"
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d = maybeDeferred(self.start)
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d.addCallback(on_start)
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d.addErrback(on_start_fail)
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self._component_starting_deferred = d
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else:
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d = maybeDeferred(on_start, None)
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elif self._component_state == "Starting":
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return self._component_starting_deferred
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elif self._component_state == "Started":
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d = succeed(True)
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else:
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d = fail("Cannot start a component not in a Stopped state!")
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return d
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def _component_stop(self):
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def on_stop(result):
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self._component_state = "Stopped"
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if self._component_timer and self._component_timer.running:
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self._component_timer.stop()
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return True
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def on_stop_fail(result):
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self._component_state = "Started"
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self._component_stopping_deferred = None
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log.error(result)
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return result
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if self._component_state != "Stopped" and self._component_state != "Stopping":
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if hasattr(self, "stop"):
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self._component_state = "Stopping"
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d = maybeDeferred(self.stop)
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d.addCallback(on_stop)
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d.addErrback(on_stop_fail)
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self._component_stopping_deferred = d
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else:
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d = maybeDeferred(on_stop, None)
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if self._component_state == "Stopping":
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return self._component_stopping_deferred
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return succeed(None)
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def _component_pause(self):
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def on_pause(result):
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self._component_state = "Paused"
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if self._component_state == "Started":
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if self._component_timer and self._component_timer.running:
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d = maybeDeferred(self._component_timer.stop)
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d.addCallback(on_pause)
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else:
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d = succeed(None)
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elif self._component_state == "Paused":
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d = succeed(None)
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else:
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d = fail("Cannot pause a component in a non-Started state!")
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return d
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def _component_resume(self):
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def on_resume(result):
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self._component_state = "Started"
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if self._component_state == "Paused":
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d = maybeDeferred(self._component_start_timer)
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d.addCallback(on_resume)
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else:
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d = fail("Component cannot be resumed from a non-Paused state!")
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return d
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def _component_shutdown(self):
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def on_stop(result):
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if hasattr(self, "shutdown"):
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return maybeDeferred(self.shutdown)
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return succeed(None)
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d = self._component_stop()
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d.addCallback(on_stop)
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return d
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def start(self):
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pass
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def stop(self):
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pass
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def update(self):
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pass
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def shutdown(self):
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pass
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class ComponentRegistry(object):
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"""
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The ComponentRegistry holds a list of currently registered
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:class:`Component` objects. It is used to manage the Components by
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starting, stopping, pausing and shutting them down.
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"""
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def __init__(self):
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self.components = {}
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# Stores all of the components that are dependent on a particular component
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self.dependents = defaultdict(list)
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def register(self, obj):
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"""
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Registers a component object with the registry. This is done
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automatically when a Component object is instantiated.
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:param obj: the Component object
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:type obj: object
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:raises ComponentAlreadyRegistered: if a component with the same name is already registered.
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"""
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name = obj._component_name
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if name in self.components:
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raise ComponentAlreadyRegistered(
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"Component already registered with name %s" % name)
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self.components[obj._component_name] = obj
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if obj._component_depend:
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for depend in obj._component_depend:
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self.dependents[depend].append(name)
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def deregister(self, obj):
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"""
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Deregisters a component from the registry. A stop will be
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issued to the component prior to deregistering it.
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:param obj: the Component object
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:type obj: object
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"""
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if obj in self.components.values():
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log.debug("Deregistering Component: %s", obj._component_name)
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d = self.stop([obj._component_name])
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def on_stop(result, name):
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del self.components[name]
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return d.addCallback(on_stop, obj._component_name)
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else:
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return succeed(None)
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def start(self, names=[]):
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"""
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Starts Components that are currently in a Stopped state and their
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dependencies. If *names* is specified, will only start those
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Components and their dependencies and if not it will start all
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registered components.
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:param names: a list of Components to start
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:type names: list
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:returns: a Deferred object that will fire once all Components have been sucessfully started
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:rtype: twisted.internet.defer.Deferred
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"""
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# Start all the components if names is empty
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if not names:
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names = self.components.keys()
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elif isinstance(names, str):
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names = [names]
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def on_depends_started(result, name):
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return self.components[name]._component_start()
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deferreds = []
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for name in names:
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if self.components[name]._component_depend:
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# This component has depends, so we need to start them first.
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d = self.start(self.components[name]._component_depend)
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d.addCallback(on_depends_started, name)
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deferreds.append(d)
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else:
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deferreds.append(self.components[name]._component_start())
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return DeferredList(deferreds)
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def stop(self, names=[]):
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"""
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Stops Components that are currently not in a Stopped state. If
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*names* is specified, then it will only stop those Components,
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and if not it will stop all the registered Components.
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:param names: a list of Components to start
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:type names: list
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:returns: a Deferred object that will fire once all Components have been sucessfully stopped
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:rtype: twisted.internet.defer.Deferred
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"""
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if not names:
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names = self.components.keys()
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elif isinstance(names, str):
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names = [names]
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def on_dependents_stopped(result, name):
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return self.components[name]._component_stop()
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stopped_in_deferred = set()
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deferreds = []
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for name in names:
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if name in stopped_in_deferred:
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continue
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if name in self.components:
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if name in self.dependents:
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# If other components depend on this component, stop them first
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d = self.stop(self.dependents[name]).addCallback(on_dependents_stopped, name)
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deferreds.append(d)
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stopped_in_deferred.update(self.dependents[name])
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else:
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deferreds.append(self.components[name]._component_stop())
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return DeferredList(deferreds)
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def pause(self, names=[]):
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"""
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Pauses Components that are currently in a Started state. If
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*names* is specified, then it will only pause those Components,
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and if not it will pause all the registered Components.
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:param names: a list of Components to pause
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:type names: list
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:returns: a Deferred object that will fire once all Components have been sucessfully paused
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:rtype: twisted.internet.defer.Deferred
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"""
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if not names:
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names = self.components.keys()
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elif isinstance(names, str):
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names = [names]
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deferreds = []
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for name in names:
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if self.components[name]._component_state == "Started":
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deferreds.append(self.components[name]._component_pause())
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return DeferredList(deferreds)
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def resume(self, names=[]):
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"""
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Resumes Components that are currently in a Paused state. If
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*names* is specified, then it will only resume those Components,
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and if not it will resume all the registered Components.
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:param names: a list of Components to resume
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:type names: list
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:returns: a Deferred object that will fire once all Components have been successfully resumed
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:rtype: twisted.internet.defer.Deferred
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"""
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if not names:
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names = self.components.keys()
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elif isinstance(names, str):
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names = [names]
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deferreds = []
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for name in names:
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if self.components[name]._component_state == "Paused":
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deferreds.append(self.components[name]._component_resume())
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return DeferredList(deferreds)
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def shutdown(self):
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"""
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Shutdowns all Components regardless of state. This will call
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:meth:`stop` on call the components prior to shutting down. This should
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be called when the program is exiting to ensure all Components have a
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chance to properly shutdown.
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:returns: a Deferred object that will fire once all Components have been successfully shut down
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:rtype: twisted.internet.defer.Deferred
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"""
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def on_success(result, key):
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del _ComponentRegistry.components[key]
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return succeed(result)
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def on_stopped(result):
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return DeferredList(map(lambda t: t[1]._component_shutdown().addCallback(on_success, t[0]),
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self.components.items()))
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return self.stop(self.components.keys()).addCallback(on_stopped)
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def update(self):
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"""
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Updates all Components that are in a Started state.
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"""
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for component in self.components.items():
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component.update()
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_ComponentRegistry = ComponentRegistry()
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deregister = _ComponentRegistry.deregister
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start = _ComponentRegistry.start
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stop = _ComponentRegistry.stop
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pause = _ComponentRegistry.pause
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resume = _ComponentRegistry.resume
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update = _ComponentRegistry.update
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shutdown = _ComponentRegistry.shutdown
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def get(name):
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"""
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Return a reference to a component.
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:param name: the Component name to get
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:type name: string
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:returns: the Component object
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:rtype: object
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:raises KeyError: if the Component does not exist
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"""
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return _ComponentRegistry.components[name]
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