class documentation

class twisted.internet.asyncioreactor.AsyncioSelectorReactor(PosixReactorBase): (source)

Implements interfaces: twisted.internet.interfaces.IReactorFDSet

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Reactor running on top of asyncio.SelectorEventLoop.

On POSIX platforms, the default event loop is asyncio.SelectorEventLoop. On Windows, the default event loop on Python 3.7 and older is asyncio.WindowsSelectorEventLoop, but on Python 3.8 and newer the default event loop is asyncio.WindowsProactorEventLoop which is incompatible with AsyncioSelectorReactor. Applications that use AsyncioSelectorReactor on Windows with Python 3.8+ must call asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy()) before instantiating and running AsyncioSelectorReactor.

Method __init__ Undocumented
Method addReader I add reader to the set of file descriptors to get read events for.
Method addWriter I add writer to the set of file descriptors to get write events for.
Method removeReader Removes an object previously added with addReader.
Method removeWriter Removes an object previously added with addWriter.
Method removeAll Remove all readers and writers.
Method getReaders Return the list of file descriptors currently monitored for input events by the reactor.
Method getWriters Return the list file descriptors currently monitored for output events by the reactor.
Method iterate See twisted.internet.interfaces.IReactorCore.iterate.
Method run Undocumented
Method stop See twisted.internet.interfaces.IReactorCore.stop.
Method crash See twisted.internet.interfaces.IReactorCore.crash.
Class Variable seconds Undocumented
Method callLater See twisted.internet.interfaces.IReactorTime.callLater.
Method callFromThread Undocumented
Class Variable _asyncClosed Undocumented
Class Variable _log Undocumented
Instance Variable _asyncioEventloop Undocumented
Instance Variable _writers Undocumented
Instance Variable _readers Undocumented
Instance Variable _continuousPolling Undocumented
Instance Variable _scheduledAt Undocumented
Instance Variable _timerHandle Undocumented
Method _unregisterFDInAsyncio Compensate for a bug in asyncio where it will not unregister a FD that it cannot handle in the epoll loop. It touches internal asyncio code.
Method _readOrWrite Undocumented
Instance Variable _justStopped Undocumented
Method _onTimer Undocumented
Method _reschedule Undocumented
Method _moveCallLaterSooner Undocumented

Inherited from PosixReactorBase:

Method installWaker Install a `waker' to allow threads and signals to wake up the IO thread.
Instance Variable waker Undocumented
Method spawnProcess Spawn a process, with a process protocol.
Method listenUDP Connects a given DatagramProtocol to the given numeric UDP port.
Method listenMulticast Connects a given DatagramProtocol to the given numeric UDP port.
Method connectUNIX Connect a client protocol to a UNIX socket.
Method listenUNIX Listen on a UNIX socket.
Method listenUNIXDatagram Connects a given DatagramProtocol to the given path.
Method connectUNIXDatagram Connects a ConnectedDatagramProtocol instance to a path.
Method adoptStreamPort Create a new IListeningPort from an already-initialized socket.
Method adoptStreamConnection
Method adoptDatagramPort Add an existing listening SOCK_DGRAM socket to the reactor to monitor for read and write readiness.
Method listenTCP Connects a given protocol factory to the given numeric TCP/IP port.
Method connectTCP Connect a TCP client.
Method connectSSL Connect a client Protocol to a remote SSL socket.
Method listenSSL Connects a given protocol factory to the given numeric TCP/IP port. The connection is a SSL one, using contexts created by the context factory.
Instance Variable _childWaker None or a reference to the _SIGCHLDWaker which is used to properly notice child process termination.
Method _handleSignals Extend the basic signal handling logic to also support handling SIGCHLD to know when to try to reap child processes.
Method _uninstallHandler If a child waker was created and installed, uninstall it now.
Class Variable _supportedAddressFamilies Undocumented
Method _removeAll Remove all readers and writers, and list of removed IReadDescriptors and IWriteDescriptors.

Inherited from _SignalReactorMixin (via PosixReactorBase):

Method startRunning Extend the base implementation in order to remember whether signal handlers should be installed later.
Method mainLoop Undocumented
Instance Variable _installSignalHandlers A flag which indicates whether any signal handlers will be installed during startup. This includes handlers for SIGCHLD to monitor child processes, and SIGINT, SIGTERM, and SIGBREAK to stop the reactor.
Method _reallyStartRunning Extend the base implementation by also installing signal handlers, if self._installSignalHandlers is true.

Inherited from _DisconnectSelectableMixin (via PosixReactorBase):

Method _disconnectSelectable Utility function for disconnecting a selectable.

Inherited from ReactorBase (via PosixReactorBase):

Instance Variable running See IReactorCore.running
Class Variable installed Undocumented
Instance Variable usingThreads Undocumented
Class Variable __name__ Undocumented
Instance Variable threadCallQueue Undocumented
Method wakeUp Wake up the event loop.
Method doIteration Do one iteration over the readers and writers which have been added.
Method resolve Return a Deferred that will resolve a hostname.
Method sigInt Handle a SIGINT interrupt.
Method sigBreak Handle a SIGBREAK interrupt.
Method sigTerm Handle a SIGTERM interrupt.
Method disconnectAll Disconnect every reader, and writer in the system.
Method fireSystemEvent See twisted.internet.interfaces.IReactorCore.fireSystemEvent.
Method addSystemEventTrigger See twisted.internet.interfaces.IReactorCore.addSystemEventTrigger.
Method removeSystemEventTrigger See twisted.internet.interfaces.IReactorCore.removeSystemEventTrigger.
Method callWhenRunning See twisted.internet.interfaces.IReactorCore.callWhenRunning.
Method startRunning Method called when reactor starts: do some initialization and fire startup events.
Method getDelayedCalls No summary
Method timeout Determine the longest time the reactor may sleep (waiting on I/O notification, perhaps) before it must wake up to service a time-related event.
Method runUntilCurrent Run all pending timed calls.
Instance Variable threadpool Undocumented
Instance Variable threadpoolShutdownID Undocumented
Method getThreadPool See twisted.internet.interfaces.IReactorThreads.getThreadPool.
Method callInThread See twisted.internet.interfaces.IReactorInThreads.callInThread.
Method suggestThreadPoolSize See twisted.internet.interfaces.IReactorThreads.suggestThreadPoolSize.
Instance Variable _stopped A flag which is true between paired calls to reactor.run and reactor.stop. This should be replaced with an explicit state machine.
Instance Variable _started A flag which is true from the time reactor.run is called until the time reactor.run returns. This is used to prevent calls to reactor.run on a running reactor. This should be replaced with an explicit state machine.
Instance Variable _registerAsIOThread A flag controlling whether the reactor will register the thread it is running in as the I/O thread when it starts. If True, registration will be done, otherwise it will not be.
Instance Variable _exitSignal See _ISupportsExitSignalCapturing._exitSignal
Instance Variable _eventTriggers Undocumented
Instance Variable _pendingTimedCalls Undocumented
Instance Variable _newTimedCalls Undocumented
Instance Variable _cancellations Undocumented
Instance Variable _startedBefore Undocumented
Instance Variable _internalReaders Undocumented
Class Variable _lock Undocumented
Method _reallyStartRunning Method called to transition to the running state. This should happen in the during startup event trigger phase.
Method _cancelCallLater Undocumented
Method _insertNewDelayedCalls Undocumented
Method _checkProcessArgs Check for valid arguments and environment to spawnProcess.
Instance Variable _threadpoolStartupID Undocumented
Method _initThreads Undocumented
Method _initThreadPool Create the threadpool accessible with callFromThread.
Method _stopThreadPool No summary

Inherited from PluggableResolverMixin (via PosixReactorBase, ReactorBase):

Instance Variable resolver The installed IResolverSimple.
Method installResolver See IReactorPluggableResolver.
Method installNameResolver See IReactorPluggableNameResolver.
Property nameResolver Implementation of read-only IReactorPluggableNameResolver.nameResolver.
Instance Variable _nameResolver The installed IHostnameResolver.
_asyncClosed = (source)

Undocumented

(type: bool)
_log = (source)

Undocumented

def __init__(self, eventloop=None): (source)

Undocumented

ParameterseventloopUndocumented (type: Optional[SelectorEventLoop])
_asyncioEventloop = (source)

Undocumented

(type: SelectorEventLoop)
_writers = (source)

Undocumented

(type: Dict[Type[FileDescriptor], int])
_readers = (source)

Undocumented

(type: Dict[Type[FileDescriptor], int])
_continuousPolling = (source)

Undocumented

_scheduledAt = (source)

Undocumented

_timerHandle = (source)

Undocumented

def _unregisterFDInAsyncio(self, fd): (source)

Compensate for a bug in asyncio where it will not unregister a FD that it cannot handle in the epoll loop. It touches internal asyncio code.

A description of the bug by markrwilliams:

The add_writer method of asyncio event loops isn't atomic because all the Selector classes in the selector module internally record a file object before passing it to the platform's selector implementation. If the platform's selector decides the file object isn't acceptable, the resulting exception doesn't cause the Selector to un-track the file object.

The failing/hanging stdio test goes through the following sequence of events (roughly):

* The first connection.write(intToByte(value)) call hits the asyncio reactor's addWriter method.

* addWriter calls the asyncio loop's add_writer method, which happens to live on _BaseSelectorEventLoop.

* The asyncio loop's add_writer method checks if the file object has been registered before via the selector's get_key method.

* It hasn't, so the KeyError block runs and calls the selector's register method

* Code examples that follow use EpollSelector, but the code flow holds true for any other selector implementation. The selector's register method first calls through to the next register method in the MRO

* That next method is always _BaseSelectorImpl.register which creates a SelectorKey instance for the file object, stores it under the file object's file descriptor, and then returns it.

* Control returns to the concrete selector implementation, which asks the operating system to track the file descriptor using the right API.

* The operating system refuses! An exception is raised that, in this case, the asyncio reactor handles by creating a _ContinuousPolling object to watch the file descriptor.

* The second connection.write(intToByte(value)) call hits the asyncio reactor's addWriter method, which hits the add_writer method. But the loop's selector's get_key method now returns a SelectorKey! Now the asyncio reactor's addWriter method thinks the asyncio loop will watch the file descriptor, even though it won't.

def _readOrWrite(self, selectable, read): (source)

Undocumented

def addReader(self, reader): (source)

I add reader to the set of file descriptors to get read events for.

ParametersreaderAn IReadDescriptor provider that will be checked for read events until it is removed from the reactor with removeReader.
def addWriter(self, writer): (source)

I add writer to the set of file descriptors to get write events for.

ParameterswriterAn IWriteDescriptor provider that will be checked for write events until it is removed from the reactor with removeWriter.
def removeReader(self, reader): (source)
def removeWriter(self, writer): (source)
def removeAll(self): (source)

Remove all readers and writers.

Should not remove reactor internal reactor connections (like a waker).

ReturnsA list of IReadDescriptor and IWriteDescriptor providers which were removed.
def getReaders(self): (source)

Return the list of file descriptors currently monitored for input events by the reactor.

Returnsthe list of file descriptors monitored for input events.
def getWriters(self): (source)

Return the list file descriptors currently monitored for output events by the reactor.

Returnsthe list of file descriptors monitored for output events.
def iterate(self, timeout): (source)

See twisted.internet.interfaces.IReactorCore.iterate.

def run(self, installSignalHandlers=True): (source)
_justStopped = (source)

Undocumented

(type: bool)
def stop(self): (source)

See twisted.internet.interfaces.IReactorCore.stop.

def crash(self): (source)

See twisted.internet.interfaces.IReactorCore.crash.

Reset reactor state tracking attributes and re-initialize certain state-transition helpers which were set up in __init__ but later destroyed (through use).

def _onTimer(self): (source)

Undocumented

def _reschedule(self): (source)

Undocumented

def _moveCallLaterSooner(self, tple): (source)
def callLater(self, seconds, f, *args, **kwargs): (source)

See twisted.internet.interfaces.IReactorTime.callLater.

def callFromThread(self, f, *args, **kwargs): (source)
API Documentation for Twisted, generated by pydoctor 20.12.1 at 2021-02-28 19:53:36.