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() -> boolStops 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() -> booldone
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() -> boolReturn 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.NoReturnMark 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. |