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- # Copyright 2022 The Matrix.org Foundation C.I.C.
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
-
- import logging
- import time
- from selectors import SelectSelector, _PollLikeSelector # type: ignore[attr-defined]
- from typing import Any, Callable, Iterable
-
- from prometheus_client import Histogram, Metric
- from prometheus_client.core import REGISTRY, GaugeMetricFamily
-
- from twisted.internet import reactor, selectreactor
- from twisted.internet.asyncioreactor import AsyncioSelectorReactor
-
- from synapse.metrics._types import Collector
-
- try:
- from selectors import KqueueSelector
- except ImportError:
-
- class KqueueSelector: # type: ignore[no-redef]
- pass
-
-
- try:
- from twisted.internet.epollreactor import EPollReactor
- except ImportError:
-
- class EPollReactor: # type: ignore[no-redef]
- pass
-
-
- try:
- from twisted.internet.pollreactor import PollReactor
- except ImportError:
-
- class PollReactor: # type: ignore[no-redef]
- pass
-
-
- logger = logging.getLogger(__name__)
-
- #
- # Twisted reactor metrics
- #
-
- tick_time = Histogram(
- "python_twisted_reactor_tick_time",
- "Tick time of the Twisted reactor (sec)",
- buckets=[0.001, 0.002, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5],
- )
-
-
- class CallWrapper:
- """A wrapper for a callable which records the time between calls"""
-
- def __init__(self, wrapped: Callable[..., Any]):
- self.last_polled = time.time()
- self._wrapped = wrapped
-
- def __call__(self, *args, **kwargs) -> Any: # type: ignore[no-untyped-def]
- # record the time since this was last called. This gives a good proxy for
- # how long it takes to run everything in the reactor - ie, how long anything
- # waiting for the next tick will have to wait.
- tick_time.observe(time.time() - self.last_polled)
-
- ret = self._wrapped(*args, **kwargs)
-
- self.last_polled = time.time()
- return ret
-
-
- class ObjWrapper:
- """A wrapper for an object which wraps a specified method in CallWrapper.
-
- Other methods/attributes are passed to the original object.
-
- This is necessary when the wrapped object does not allow the attribute to be
- overwritten.
- """
-
- def __init__(self, wrapped: Any, method_name: str):
- self._wrapped = wrapped
- self._method_name = method_name
- self._wrapped_method = CallWrapper(getattr(wrapped, method_name))
-
- def __getattr__(self, item: str) -> Any:
- if item == self._method_name:
- return self._wrapped_method
-
- return getattr(self._wrapped, item)
-
-
- class ReactorLastSeenMetric(Collector):
- def __init__(self, call_wrapper: CallWrapper):
- self._call_wrapper = call_wrapper
-
- def collect(self) -> Iterable[Metric]:
- cm = GaugeMetricFamily(
- "python_twisted_reactor_last_seen",
- "Seconds since the Twisted reactor was last seen",
- )
- cm.add_metric([], time.time() - self._call_wrapper.last_polled)
- yield cm
-
-
- # Twisted has already select a reasonable reactor for us, so assumptions can be
- # made about the shape.
- wrapper = None
- try:
- if isinstance(reactor, (PollReactor, EPollReactor)):
- reactor._poller = ObjWrapper(reactor._poller, "poll") # type: ignore[attr-defined]
- wrapper = reactor._poller._wrapped_method # type: ignore[attr-defined]
-
- elif isinstance(reactor, selectreactor.SelectReactor):
- # Twisted uses a module-level _select function.
- wrapper = selectreactor._select = CallWrapper(selectreactor._select)
-
- elif isinstance(reactor, AsyncioSelectorReactor):
- # For asyncio look at the underlying asyncio event loop.
- asyncio_loop = reactor._asyncioEventloop # A sub-class of BaseEventLoop,
-
- # A sub-class of BaseSelector.
- selector = asyncio_loop._selector # type: ignore[attr-defined]
-
- if isinstance(selector, SelectSelector):
- wrapper = selector._select = CallWrapper(selector._select) # type: ignore[attr-defined]
-
- # poll, epoll, and /dev/poll.
- elif isinstance(selector, _PollLikeSelector):
- selector._selector = ObjWrapper(selector._selector, "poll") # type: ignore[attr-defined]
- wrapper = selector._selector._wrapped_method # type: ignore[attr-defined]
-
- elif isinstance(selector, KqueueSelector):
- selector._selector = ObjWrapper(selector._selector, "control") # type: ignore[attr-defined]
- wrapper = selector._selector._wrapped_method # type: ignore[attr-defined]
-
- else:
- # E.g. this does not support the (Windows-only) ProactorEventLoop.
- logger.warning(
- "Skipping configuring ReactorLastSeenMetric: unexpected asyncio loop selector: %r via %r",
- selector,
- asyncio_loop,
- )
- except Exception as e:
- logger.warning("Configuring ReactorLastSeenMetric failed: %r", e)
-
-
- if wrapper:
- REGISTRY.register(ReactorLastSeenMetric(wrapper))
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