162 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			162 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			Python
		
	
	
| # Copyright 2022 The Matrix.org Foundation C.I.C.
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| #
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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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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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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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| 
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| import logging
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| import time
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| from selectors import SelectSelector, _PollLikeSelector  # type: ignore[attr-defined]
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| from typing import Any, Callable, Iterable
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| 
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| from prometheus_client import Histogram, Metric
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| from prometheus_client.core import REGISTRY, GaugeMetricFamily
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| 
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| from twisted.internet import reactor, selectreactor
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| from twisted.internet.asyncioreactor import AsyncioSelectorReactor
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| 
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| from synapse.metrics._types import Collector
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| 
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| try:
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|     from selectors import KqueueSelector
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| except ImportError:
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| 
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|     class KqueueSelector:  # type: ignore[no-redef]
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|         pass
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| 
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| 
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| try:
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|     from twisted.internet.epollreactor import EPollReactor
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| except ImportError:
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| 
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|     class EPollReactor:  # type: ignore[no-redef]
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|         pass
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| 
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| 
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| try:
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|     from twisted.internet.pollreactor import PollReactor
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| except ImportError:
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| 
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|     class PollReactor:  # type: ignore[no-redef]
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|         pass
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| 
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| 
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| logger = logging.getLogger(__name__)
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| 
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| #
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| # Twisted reactor metrics
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| #
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| 
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| tick_time = Histogram(
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|     "python_twisted_reactor_tick_time",
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|     "Tick time of the Twisted reactor (sec)",
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|     buckets=[0.001, 0.002, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5],
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| )
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| 
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| 
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| class CallWrapper:
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|     """A wrapper for a callable which records the time between calls"""
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| 
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|     def __init__(self, wrapped: Callable[..., Any]):
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|         self.last_polled = time.time()
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|         self._wrapped = wrapped
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| 
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|     def __call__(self, *args, **kwargs) -> Any:  # type: ignore[no-untyped-def]
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|         # record the time since this was last called. This gives a good proxy for
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|         # how long it takes to run everything in the reactor - ie, how long anything
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|         # waiting for the next tick will have to wait.
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|         tick_time.observe(time.time() - self.last_polled)
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| 
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|         ret = self._wrapped(*args, **kwargs)
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| 
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|         self.last_polled = time.time()
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|         return ret
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| 
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| 
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| class ObjWrapper:
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|     """A wrapper for an object which wraps a specified method in CallWrapper.
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| 
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|     Other methods/attributes are passed to the original object.
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| 
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|     This is necessary when the wrapped object does not allow the attribute to be
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|     overwritten.
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|     """
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| 
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|     def __init__(self, wrapped: Any, method_name: str):
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|         self._wrapped = wrapped
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|         self._method_name = method_name
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|         self._wrapped_method = CallWrapper(getattr(wrapped, method_name))
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| 
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|     def __getattr__(self, item: str) -> Any:
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|         if item == self._method_name:
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|             return self._wrapped_method
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| 
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|         return getattr(self._wrapped, item)
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| 
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| 
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| class ReactorLastSeenMetric(Collector):
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|     def __init__(self, call_wrapper: CallWrapper):
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|         self._call_wrapper = call_wrapper
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| 
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|     def collect(self) -> Iterable[Metric]:
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|         cm = GaugeMetricFamily(
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|             "python_twisted_reactor_last_seen",
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|             "Seconds since the Twisted reactor was last seen",
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|         )
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|         cm.add_metric([], time.time() - self._call_wrapper.last_polled)
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|         yield cm
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| 
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| 
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| # Twisted has already select a reasonable reactor for us, so assumptions can be
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| # made about the shape.
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| wrapper = None
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| try:
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|     if isinstance(reactor, (PollReactor, EPollReactor)):
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|         reactor._poller = ObjWrapper(reactor._poller, "poll")  # type: ignore[attr-defined]
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|         wrapper = reactor._poller._wrapped_method  # type: ignore[attr-defined]
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| 
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|     elif isinstance(reactor, selectreactor.SelectReactor):
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|         # Twisted uses a module-level _select function.
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|         wrapper = selectreactor._select = CallWrapper(selectreactor._select)
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| 
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|     elif isinstance(reactor, AsyncioSelectorReactor):
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|         # For asyncio look at the underlying asyncio event loop.
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|         asyncio_loop = reactor._asyncioEventloop  # A sub-class of BaseEventLoop,
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| 
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|         # A sub-class of BaseSelector.
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|         selector = asyncio_loop._selector  # type: ignore[attr-defined]
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| 
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|         if isinstance(selector, SelectSelector):
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|             wrapper = selector._select = CallWrapper(selector._select)  # type: ignore[attr-defined]
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| 
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|         # poll, epoll, and /dev/poll.
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|         elif isinstance(selector, _PollLikeSelector):
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|             selector._selector = ObjWrapper(selector._selector, "poll")  # type: ignore[attr-defined]
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|             wrapper = selector._selector._wrapped_method  # type: ignore[attr-defined]
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| 
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|         elif isinstance(selector, KqueueSelector):
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|             selector._selector = ObjWrapper(selector._selector, "control")  # type: ignore[attr-defined]
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|             wrapper = selector._selector._wrapped_method  # type: ignore[attr-defined]
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| 
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|         else:
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|             # E.g. this does not support the (Windows-only) ProactorEventLoop.
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|             logger.warning(
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|                 "Skipping configuring ReactorLastSeenMetric: unexpected asyncio loop selector: %r via %r",
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|                 selector,
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|                 asyncio_loop,
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|             )
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| except Exception as e:
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|     logger.warning("Configuring ReactorLastSeenMetric failed: %r", e)
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| 
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| 
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| if wrapper:
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|     REGISTRY.register(ReactorLastSeenMetric(wrapper))
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