Nexus task cancellation #1204
Nexus task cancellation #1204
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…_manager. Finish implementing nexus task cancellation
…hat weren't relevant
| class _NexusTaskCancellation(nexusrpc.handler.OperationTaskCancellation): | ||
| def __init__(self): | ||
| self._thread_evt = threading.Event() | ||
| self._aysnc_evt = asyncio.Event() |
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| self._aysnc_evt = asyncio.Event() | |
| self._async_evt = asyncio.Event() |
| async def wait_until_cancelled(self) -> None: | ||
| await self._aysnc_evt.wait() | ||
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| def cancel(self, reason: Optional[str] = None) -> bool: |
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Probably no need to return a never-read value from an effectively module-private method, but meh
| async def wait_until_cancelled(self) -> None: | ||
| await self._aysnc_evt.wait() | ||
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| def cancel(self, reason: Optional[str] = None) -> bool: |
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Is there a possibility of reason being none? Even if there is (some newer proto value on the server that we don't have an entry for yet), is there any value in defaulting this parameter (or the one on the cancel call that calls this)?
| await self._aysnc_evt.wait() | ||
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| def cancel(self, reason: Optional[str] = None) -> bool: | ||
| if self._thread_evt.is_set(): |
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No real value in Python in double-checked in and out of lock, can just rely on the in-lock check (arguably lock not as valuable in Python as it is in other langs, could just change top of cancellation_reason to have an if self._thread_evt.is_set() instead of the lock, but it's fine)
What was changed
Why?
Nexus operation handlers should be able to handle the case where a call
start_operationor call tocancel_operationis interrupted. The most common occurrence of this is a timeout where the call fails to return in time. The new cancellation objects attached to the Nexus operation context allows both sync and async functions to exit early when appropriate.These changes rely on nexus-rpc/sdk-python#31 and is the Temporal specific implementation of nexus-rpc/sdk-python#26.
Checklist
test/nexus/test_workflow_caller_errors.pywere updated to cover: