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.
Class _Timer Undocumented
Function _defaultScheduler Undocumented
def _defaultScheduler(x):
Undocumented
def coiterate(iterator):

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.

Parametersiteratorthe iterator to invoke.
Returnsa Deferred that will fire when the iterator finishes.
def cooperate(iterator):

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.

Parametersiteratorthe iterator to invoke.
Returnsa CooperativeTask object representing this task.
def deferLater(clock, delay, *args, callable=None, **kw):

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

ParametersclockThe object which will be used to schedule the delayed call. (type: IReactorTime provider)
delayThe number of seconds to wait before calling the function. (type: float or int)
callableThe object to call after the delay.
*argsThe positional arguments to pass to callable.
**kwThe keyword arguments to pass to callable.
ReturnsA deferred that fires with the result of the callable when the specified time has elapsed. (type: defer.Deferred)
def react(main, argv=(), _reactor=None):

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

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:

     def main(reactor, username, password):
         return defer.succeed('ok')

     task.react(main, ('alice', 'secret'))
ParametersmainA callable which returns a Deferred. It should take the reactor as its first parameter, followed by the elements of argv.
argvA list of arguments to pass to main. If omitted the callable will be invoked with no additional arguments.
_reactorAn implementation detail to allow easier unit testing. Do not supply this parameter.
Present Since12.3
API Documentation for twisted, generated by pydoctor at 2020-03-25 17:34:30.