twisted.internet.task : API documentation

module documentation

(source)

Scheduling utility methods and classes.

Class	LoopingCall	Call a function repeatedly.
Class	SchedulerError	No summary
Class	SchedulerStopped	The operation could not complete because the scheduler was stopped in progress or was already stopped.
Class	TaskFinished	The operation could not complete because the task was already completed, stopped, encountered an error or otherwise permanently stopped running.
Class	TaskDone	The operation could not complete because the task was already completed.
Class	TaskStopped	The operation could not complete because the task was stopped.
Class	TaskFailed	The operation could not complete because the task died with an unhandled error.
Class	NotPaused	This exception is raised when a task is resumed which was not previously paused.
Class	CooperativeTask	A `CooperativeTask` is a task object inside a `Cooperator`, which can be paused, resumed, and stopped. It can also have its completion (or termination) monitored.
Class	Cooperator	Cooperative task scheduler.
Function	coiterate	Cooperatively iterate over the given iterator, dividing runtime between it and all other iterators which have been passed to this function and not yet exhausted.
Function	cooperate	Start running the given iterator as a long-running cooperative task, by calling next() on it as a periodic timed event.
Class	Clock	Provide a deterministic, easily-controlled implementation of `IReactorTime.callLater`. This is commonly useful for writing deterministic unit tests for code which schedules events using this API.
Function	deferLater	Call the given function after a certain period of time has passed.
Function	react	Call `main` and run the reactor until the `Deferred` it returns fires or the coroutine it returns completes.
Class	_Timer	Undocumented
Variable	_EPSILON	Undocumented
Function	_defaultScheduler	Undocumented
Variable	_theCooperator	Undocumented

_EPSILON = (source)

Undocumented

(type: float)

def _defaultScheduler(x): (source)

Undocumented

_theCooperator = (source)

Undocumented

def coiterate(iterator): (source)

Cooperatively iterate over the given iterator, dividing runtime between it and all other iterators which have been passed to this function and not yet exhausted.

Parameters	iterator	the iterator to invoke.
Returns	a Deferred that will fire when the iterator finishes.

def cooperate(iterator): (source)

Start running the given iterator as a long-running cooperative task, by calling next() on it as a periodic timed event.

This is very useful if you have computationally expensive tasks that you want to run without blocking the reactor. Just break each task up so that it yields frequently, pass it in here and the global Cooperator will make sure work is distributed between them without blocking longer than a single iteration of a single task.

Parameters	iterator	the iterator to invoke.
Returns	a `CooperativeTask` object representing this task.

def deferLater(clock, delay, callable=None, *args, **kw): (source)

Call the given function after a certain period of time has passed.

Parameters	clock	The object which will be used to schedule the delayed call. (type: `IReactorTime` provider)
	delay	The number of seconds to wait before calling the function. (type: `float` or `int`)
	callable	The object to call after the delay.
	args	The positional arguments to pass to `callable`.
	kw	The keyword arguments to pass to `callable`.
Returns	A deferred that fires with the result of the callable when the specified time has elapsed. (type: `defer.Deferred`)

def react(main, argv=(), _reactor=None): (source)

Call main and run the reactor until the Deferred it returns fires or the coroutine it returns completes.

This is intended as the way to start up an application with a well-defined completion condition. Use it to write clients or one-off asynchronous operations. Prefer this to calling reactor.run directly, as this function will also:

Take care to call reactor.stop once and only once, and at the right time.
Log any failures from the Deferred returned by main.
Exit the application when done, with exit code 0 in case of success and 1 in case of failure. If main fails with a SystemExit error, the code returned is used.

The following demonstrates the signature of a main function which can be used with react:

      async def main(reactor, username, password):
          return "ok"

      task.react(main, ("alice", "secret"))

Parameters	main	A callable which returns a `Deferred` or coroutine. It should take the reactor as its first parameter, followed by the elements of `argv`.
	argv	A list of arguments to pass to `main`. If omitted the callable will be invoked with no additional arguments.
	_reactor	An implementation detail to allow easier unit testing. Do not supply this parameter.
Present Since	12.3

API Documentation for Twisted, generated by pydoctor 20.12.1 at 2021-02-28 19:53:36.