Class StreamingPullFuture (2.21.1)

Version 2.21.1

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StreamingPullFuture(manager: StreamingPullManager)

Represents a process that asynchronously performs streaming pull and schedules messages to be processed.

This future is resolved when the process is stopped (via cancel) or if it encounters an unrecoverable error. Calling .result() will cause the calling thread to block indefinitely.

Methods

StreamingPullFuture

StreamingPullFuture(manager: StreamingPullManager)

Initializes the future. Should not be called by clients.

add_done_callback

add_done_callback(fn)

Attaches a callable that will be called when the future finishes.

cancel

cancel() -> bool

Stops pulling messages and shutdowns the background thread consuming messages.

The method always returns True, as the shutdown is always initiated. However, if the background stream is already being shut down or the shutdown has completed, this method is a no-op.

.. versionchanged:: 2.4.1 The method does not block anymore, it just triggers the shutdown and returns immediately. To block until the background stream is terminated, call result() after cancelling the future.

.. versionchanged:: 2.10.0 The method always returns True instead of None.

cancelled

cancelled() -> bool

done

done()

Return True if the future was cancelled or finished executing.

exception

exception(timeout=None)

Return the exception raised by the call that the future represents.

Exceptions
Type	Description
CancelledError	If the future was cancelled.
TimeoutError	If the future didn't finish executing before the given timeout.

result

result(timeout=None)

Return the result of the call that the future represents.

Exceptions
Type	Description
CancelledError	If the future was cancelled.
TimeoutError	If the future didn't finish executing before the given timeout.
Exception	If the call raised then that exception will be raised.

running

running() -> bool

Return True if the associated Pub/Sub action has not yet completed.

set_exception

set_exception(exception: typing.Optional[BaseException])

Set the result of the future as being the given exception.

Do not use this method, it should only be used internally by the library and its unit tests.

set_result

set_result(result: typing.Any)

Set the return value of work associated with the future.

Do not use this method, it should only be used internally by the library and its unit tests.

set_running_or_notify_cancel

set_running_or_notify_cancel() -> typing.NoReturn

Mark the future as running or process any cancel notifications.

Should only be used by Executor implementations and unit tests.

If the future has been cancelled (cancel() was called and returned True) then any threads waiting on the future completing (though calls to as_completed() or wait()) are notified and False is returned.

If the future was not cancelled then it is put in the running state (future calls to running() will return True) and True is returned.

This method should be called by Executor implementations before executing the work associated with this future. If this method returns False then the work should not be executed.

Exceptions
Type	Description
RuntimeError	if this method was already called or if set_result() or set_exception() was called.