Drop uuid4 keys, raise closed error on subscription after close
parent
ac14f611b2
commit
aad6cf9070
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@ -12,7 +12,6 @@ from functools import partial
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from operator import ne
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from typing import Optional, Callable, Awaitable, Any, AsyncIterator, Protocol
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from typing import Generic, TypeVar
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from uuid import uuid4
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import trio
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from trio._core._run import Task
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@ -23,9 +22,8 @@ from trio.lowlevel import current_task
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# A regular invariant generic type
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T = TypeVar("T")
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# The type of object produced by a ReceiveChannel (covariant because
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# ReceiveChannel[Derived] can be passed to someone expecting
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# ReceiveChannel[Base])
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# covariant because AsyncReceiver[Derived] can be passed to someone
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# expecting AsyncReceiver[Base])
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ReceiveType = TypeVar("ReceiveType", covariant=True)
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@ -33,9 +31,13 @@ class AsyncReceiver(
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Protocol,
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Generic[ReceiveType],
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):
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'''An async receivable duck-type that quacks much like trio's
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``trio.abc.ReceieveChannel``.
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'''
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@abstractmethod
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async def receive(self) -> ReceiveType:
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'''Same as in ``trio``.'''
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...
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@abstractmethod
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def __aiter__(self) -> AsyncIterator[ReceiveType]:
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@ -60,7 +62,10 @@ class AsyncReceiver(
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class Lagged(trio.TooSlowError):
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'''Subscribed consumer task was too slow'''
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'''Subscribed consumer task was too slow and was overrun
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by the fastest consumer-producer pair.
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'''
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@dataclass
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@ -70,11 +75,11 @@ class BroadcastState:
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'''
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queue: deque
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# map of underlying uuid keys to receiver instances which must be
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# provided as a singleton per broadcaster set.
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# map of underlying instance id keys to receiver instances which
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# must be provided as a singleton per broadcaster set.
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subs: dict[str, int]
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# broadcast event to wakeup all sleeping consumer tasks
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# broadcast event to wake up all sleeping consumer tasks
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# on a newly produced value from the sender.
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recv_ready: Optional[tuple[str, trio.Event]] = None
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@ -84,13 +89,12 @@ class BroadcastReceiver(ReceiveChannel):
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fastest consumer.
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Additional consumer tasks can receive all produced values by registering
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with ``.subscribe()`` and receiving from thew new instance it delivers.
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with ``.subscribe()`` and receiving from the new instance it delivers.
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'''
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def __init__(
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self,
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key: str,
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rx_chan: AsyncReceiver,
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state: BroadcastState,
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receive_afunc: Optional[Callable[[], Awaitable[Any]]] = None,
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@ -98,9 +102,9 @@ class BroadcastReceiver(ReceiveChannel):
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) -> None:
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# register the original underlying (clone)
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self.key = key
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self.key = id(self)
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self._state = state
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state.subs[key] = -1
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state.subs[self.key] = -1
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# underlying for this receiver
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self._rx = rx_chan
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@ -216,29 +220,23 @@ class BroadcastReceiver(ReceiveChannel):
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provided at creation.
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'''
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# use a uuid4 for a tee-instance token
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key = str(uuid4())
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if self._closed:
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raise trio.ClosedResourceError
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state = self._state
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br = BroadcastReceiver(
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key=key,
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rx_chan=self._rx,
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state=state,
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receive_afunc=self._recv,
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)
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# assert clone in state.subs
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assert key in state.subs
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assert br.key in state.subs
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try:
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yield br
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finally:
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await br.aclose()
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# TODO:
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# - should there be some ._closed flag that causes
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# consumers to die **before** they read all queued values?
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# - if subs only open and close clones then the underlying
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# will never be killed until the last instance closes?
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# This is correct right?
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async def aclose(
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self,
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) -> None:
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@ -248,10 +246,7 @@ class BroadcastReceiver(ReceiveChannel):
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# XXX: leaving it like this consumers can still get values
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# up to the last received that still reside in the queue.
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# Is this what we want?
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self._state.subs.pop(self.key)
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# if not self._state.subs:
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# await self._rx.aclose()
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self._closed = True
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@ -265,7 +260,6 @@ def broadcast_receiver(
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) -> BroadcastReceiver:
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return BroadcastReceiver(
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str(uuid4()),
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recv_chan,
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state=BroadcastState(
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queue=deque(maxlen=max_buffer_size),
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