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Tighten up IterativeFinder logic to respect max_records better, and wait after task cancel().

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Also make IterativeFinder a proper AsyncGenerator. This gives it an offically recognized aclose() method and could help with clean finalization.
This commit is contained in:
Jonathan Moody 2022-04-11 18:17:16 -04:00
parent 5c708e1c6f
commit b036961954
1 changed files with 76 additions and 23 deletions
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99
lbry/dht/protocol/iterative_find.py
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@ -1,6 +1,7 @@
import asyncio
from itertools import chain
from collections import defaultdict, OrderedDict
from collections.abc import AsyncGenerator
import typing
import logging
from typing import TYPE_CHECKING
@ -71,7 +72,7 @@ def get_shortlist(routing_table: 'TreeRoutingTable', key: bytes,
return shortlist or routing_table.find_close_peers(key)
class IterativeFinder:
class IterativeFinder(AsyncGenerator):
def __init__(self, loop: asyncio.AbstractEventLoop, peer_manager: 'PeerManager',
routing_table: 'TreeRoutingTable', protocol: 'KademliaProtocol', key: bytes,
max_results: typing.Optional[int] = constants.K,
@ -98,6 +99,8 @@ class IterativeFinder:
self.iteration_count = 0
self.running = False
self.tasks: typing.List[asyncio.Task] = []
self.generator = None
for peer in get_shortlist(routing_table, key, shortlist):
if peer.node_id:
self._add_active(peer, force=True)
@ -163,12 +166,16 @@ class IterativeFinder:
except asyncio.TimeoutError:
self._reset_closest(peer)
return
except asyncio.CancelledError:
log.debug("%s[%x] cancelled probe",
type(self).__name__, id(self))
return
except ValueError as err:
log.warning(str(err))
self._reset_closest(peer)
return
except TransportNotConnected:
return self.aclose()
return self._aclose()
except RemoteException:
self._reset_closest(peer)
return
@ -182,13 +189,17 @@ class IterativeFinder:
added = 0
for index, peer in enumerate(self.active.keys()):
if index == 0:
log.debug("closest to probe: %s", peer.node_id.hex()[:8])
log.debug("%s[%x] closest to probe: %s",
type(self).__name__, id(self),
peer.node_id.hex()[:8])
if peer in self.contacted:
continue
if len(self.running_probes) >= constants.ALPHA:
break
if index > (constants.K + len(self.running_probes)):
break
if self.iteration_count + self.iteration_queue.qsize() >= self.max_results:
break
origin_address = (peer.address, peer.udp_port)
if origin_address in self.exclude:
continue
@ -198,9 +209,13 @@ class IterativeFinder:
continue
self._schedule_probe(peer)
added += 1
log.debug("running %d probes for key %s", len(self.running_probes), self.key.hex()[:8])
log.debug("%s[%x] running %d probes for key %s",
type(self).__name__, id(self),
len(self.running_probes), self.key.hex()[:8])
if not added and not self.running_probes:
log.debug("search for %s exhausted", self.key.hex()[:8])
log.debug("%s[%x] search for %s exhausted",
type(self).__name__, id(self),
self.key.hex()[:8])
self.search_exhausted()
def _schedule_probe(self, peer: 'KademliaPeer'):
@ -217,38 +232,76 @@ class IterativeFinder:
self.running_probes[peer] = t
def _log_state(self):
log.debug("[%s] check result: %i active nodes %i contacted",
self.key.hex()[:8], len(self.active), len(self.contacted))
log.debug("%s[%x] [%s] check result: %i active nodes %i contacted %i produced %i queued",
type(self).__name__, id(self), self.key.hex()[:8],
len(self.active), len(self.contacted),
self.iteration_count, self.iteration_queue.qsize())
async def _generator_func(self):
try:
while self.iteration_count < self.max_results:
if self.iteration_count == 0:
result = self.get_initial_result() or await self.iteration_queue.get()
else:
result = await self.iteration_queue.get()
if not result:
# no more results
await self._aclose(reason="no more results")
self.generator = None
return
self.iteration_count += 1
yield result
# reached max_results limit
await self._aclose(reason="max_results reached")
self.generator = None
return
except asyncio.CancelledError:
await self._aclose(reason="cancelled")
self.generator = None
raise
except GeneratorExit:
await self._aclose(reason="generator exit")
self.generator = None
raise
def __aiter__(self):
if self.running:
raise Exception("already running")
self.running = True
self.generator = self._generator_func()
self.loop.call_soon(self._search_round)
return self
return super().__aiter__()
async def __anext__(self) -> typing.List['KademliaPeer']:
try:
if self.iteration_count == 0:
result = self.get_initial_result() or await self.iteration_queue.get()
else:
result = await self.iteration_queue.get()
if not result:
raise StopAsyncIteration
self.iteration_count += 1
return result
except (asyncio.CancelledError, StopAsyncIteration):
self.loop.call_soon(self.aclose)
raise
return await super().__anext__()
def aclose(self):
async def asend(self, val):
return await self.generator.asend(val)
async def athrow(self, typ, val=None, tb=None):
return await self.generator.athrow(typ, val, tb)
async def _aclose(self, reason="?"):
self.running = False
self.iteration_queue.put_nowait(None)
for task in chain(self.tasks, self.running_probes.values()):
running_tasks = list(chain(self.tasks, self.running_probes.values()))
for task in running_tasks:
task.cancel()
if len(running_tasks):
await asyncio.wait(running_tasks, loop=self.loop)
log.debug("%s[%x] [%s] async close because %s: %i active nodes %i contacted %i produced %i queued",
type(self).__name__, id(self), self.key.hex()[:8],
reason, len(self.active), len(self.contacted),
self.iteration_count, self.iteration_queue.qsize())
self.tasks.clear()
self.running_probes.clear()
async def aclose(self):
if self.generator:
await super().aclose()
self.generator = None
log.debug("%s[%x] [%s] async close completed",
type(self).__name__, id(self), self.key.hex()[:8])
class IterativeNodeFinder(IterativeFinder):
def __init__(self, loop: asyncio.AbstractEventLoop, peer_manager: 'PeerManager',