py-libp2p/libp2p/pubsub/subscription.py
mhchia 095a848f30
Add clean-up logics into TrioSubscriptionAPI
Register an `unsubscribe_fn` when initializing the TrioSubscriptionAPI.
`unsubscribe_fn` is called when subscription is unsubscribed.
2020-01-28 00:29:05 +08:00

47 lines
1.4 KiB
Python

from types import TracebackType
from typing import AsyncIterator, Optional, Type
import trio
from .abc import ISubscriptionAPI
from .pb import rpc_pb2
from .typing import UnsubscribeFn
class BaseSubscriptionAPI(ISubscriptionAPI):
async def __aenter__(self) -> "BaseSubscriptionAPI":
await trio.hazmat.checkpoint()
return self
async def __aexit__(
self,
exc_type: "Optional[Type[BaseException]]",
exc_value: "Optional[BaseException]",
traceback: "Optional[TracebackType]",
) -> None:
await self.unsubscribe()
class TrioSubscriptionAPI(BaseSubscriptionAPI):
receive_channel: "trio.MemoryReceiveChannel[rpc_pb2.Message]"
unsubscribe_fn: UnsubscribeFn
def __init__(
self,
receive_channel: "trio.MemoryReceiveChannel[rpc_pb2.Message]",
unsubscribe_fn: UnsubscribeFn,
) -> None:
self.receive_channel = receive_channel
# Ignore type here since mypy complains: https://github.com/python/mypy/issues/2427
self.unsubscribe_fn = unsubscribe_fn # type: ignore
async def unsubscribe(self) -> None:
# Ignore type here since mypy complains: https://github.com/python/mypy/issues/2427
await self.unsubscribe_fn() # type: ignore
def __aiter__(self) -> AsyncIterator[rpc_pb2.Message]:
return self.receive_channel.__aiter__()
async def get(self) -> rpc_pb2.Message:
return await self.receive_channel.receive()