wehub-resource-sync
66 lines
2.5 KiB
Python
66 lines
2.5 KiB
Python
# Adapted from [aiodebug](https://gitlab.com/quantlane/libs/aiodebug)
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# Copyright 2016-2022 Quantlane s.r.o.
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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# http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# Modifications:
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# - Removed the dependency to `logwood`.
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# - Renamed `monitor_loop_lag.enable()` to just `enable_monitor_loop_lag()`.
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# - Miscellaneous changes to make it work with Ray.
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import asyncio
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import asyncio.events
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from typing import Callable, Optional, Set
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# Strong references to background tasks to prevent them from being garbage
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# collected mid-execution. The asyncio event loop only keeps weak references
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# to tasks, so a task with no other strong references can be collected at
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# any time. See https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task
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_BACKGROUND_TASKS: Set[asyncio.Task] = set()
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def enable_monitor_loop_lag(
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callback: Callable[[float], None],
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interval_s: float = 0.25,
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loop: Optional[asyncio.AbstractEventLoop] = None,
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) -> None:
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"""Start logging event loop lags to the callback.
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In ideal circumstances they should be very close to zero. Lags may increase
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if event loop callbacks block for too long.
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Note: this works for all event loops, including uvloop.
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Args:
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callback: Callback to call with the lag in seconds.
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interval_s: How often to measure the lag, in seconds.
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loop: The event loop to monitor. If None, uses the running loop.
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"""
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if loop is None:
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loop = asyncio.get_running_loop()
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if loop is None:
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raise ValueError("No provided loop, nor running loop found.")
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async def monitor():
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while loop.is_running():
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t0 = loop.time()
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await asyncio.sleep(interval_s)
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lag = loop.time() - t0 - interval_s # Should be close to zero.
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callback(lag)
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task = loop.create_task(monitor(), name="async_utils.monitor_loop_lag")
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# Keep a strong reference so the task isn't garbage collected mid-execution.
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_BACKGROUND_TASKS.add(task)
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task.add_done_callback(_BACKGROUND_TASKS.discard)
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