MatrixSynapse/synapse/util/__init__.py

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# Copyright 2014-2016 OpenMarket Ltd
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#
# 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 json
import logging
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import typing
from typing import Any, Callable, Dict, Generator, Optional
import attr
from frozendict import frozendict
from matrix_common.versionstring import get_distribution_version_string
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from twisted.internet import defer, task
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from twisted.internet.defer import Deferred
from twisted.internet.interfaces import IDelayedCall, IReactorTime
from twisted.internet.task import LoopingCall
from twisted.python.failure import Failure
from synapse.logging import context
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if typing.TYPE_CHECKING:
pass
logger = logging.getLogger(__name__)
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def _reject_invalid_json(val: Any) -> None:
"""Do not allow Infinity, -Infinity, or NaN values in JSON."""
raise ValueError("Invalid JSON value: '%s'" % val)
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def _handle_frozendict(obj: Any) -> Dict[Any, Any]:
"""Helper for json_encoder. Makes frozendicts serializable by returning
the underlying dict
"""
if type(obj) is frozendict:
# fishing the protected dict out of the object is a bit nasty,
# but we don't really want the overhead of copying the dict.
try:
# Safety: we catch the AttributeError immediately below.
# See https://github.com/matrix-org/python-canonicaljson/issues/36#issuecomment-927816293
# for discussion on how frozendict's internals have changed over time.
return obj._dict # type: ignore[attr-defined]
except AttributeError:
# When the C implementation of frozendict is used,
# there isn't a `_dict` attribute with a dict
# so we resort to making a copy of the frozendict
return dict(obj)
raise TypeError(
"Object of type %s is not JSON serializable" % obj.__class__.__name__
)
# A custom JSON encoder which:
# * handles frozendicts
# * produces valid JSON (no NaNs etc)
# * reduces redundant whitespace
json_encoder = json.JSONEncoder(
allow_nan=False, separators=(",", ":"), default=_handle_frozendict
)
# Create a custom decoder to reject Python extensions to JSON.
json_decoder = json.JSONDecoder(parse_constant=_reject_invalid_json)
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def unwrapFirstError(failure: Failure) -> Failure:
# Deprecated: you probably just want to catch defer.FirstError and reraise
# the subFailure's value, which will do a better job of preserving stacktraces.
# (actually, you probably want to use yieldable_gather_results anyway)
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failure.trap(defer.FirstError)
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return failure.value.subFailure # type: ignore[union-attr] # Issue in Twisted's annotations
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@attr.s(slots=True)
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class Clock:
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"""
A Clock wraps a Twisted reactor and provides utilities on top of it.
Args:
reactor: The Twisted reactor to use.
"""
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_reactor: IReactorTime = attr.ib()
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@defer.inlineCallbacks # type: ignore[arg-type] # Issue in Twisted's type annotations
def sleep(self, seconds: float) -> "Generator[Deferred[float], Any, Any]":
d: defer.Deferred[float] = defer.Deferred()
with context.PreserveLoggingContext():
self._reactor.callLater(seconds, d.callback, seconds)
res = yield d
return res
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def time(self) -> float:
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"""Returns the current system time in seconds since epoch."""
return self._reactor.seconds()
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def time_msec(self) -> int:
"""Returns the current system time in milliseconds since epoch."""
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return int(self.time() * 1000)
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def looping_call(
self, f: Callable, msec: float, *args: Any, **kwargs: Any
) -> LoopingCall:
"""Call a function repeatedly.
Waits `msec` initially before calling `f` for the first time.
Note that the function will be called with no logcontext, so if it is anything
other than trivial, you probably want to wrap it in run_as_background_process.
Args:
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f: The function to call repeatedly.
msec: How long to wait between calls in milliseconds.
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*args: Postional arguments to pass to function.
**kwargs: Key arguments to pass to function.
"""
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call = task.LoopingCall(f, *args, **kwargs)
call.clock = self._reactor
d = call.start(msec / 1000.0, now=False)
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d.addErrback(log_failure, "Looping call died", consumeErrors=False)
return call
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def call_later(
self, delay: float, callback: Callable, *args: Any, **kwargs: Any
) -> IDelayedCall:
"""Call something later
Note that the function will be called with no logcontext, so if it is anything
other than trivial, you probably want to wrap it in run_as_background_process.
Args:
delay: How long to wait in seconds.
callback: Function to call
*args: Postional arguments to pass to function.
**kwargs: Key arguments to pass to function.
"""
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def wrapped_callback(*args: Any, **kwargs: Any) -> None:
with context.PreserveLoggingContext():
callback(*args, **kwargs)
with context.PreserveLoggingContext():
return self._reactor.callLater(delay, wrapped_callback, *args, **kwargs)
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def cancel_call_later(self, timer: IDelayedCall, ignore_errs: bool = False) -> None:
try:
timer.cancel()
except Exception:
if not ignore_errs:
raise
def log_failure(
failure: Failure, msg: str, consumeErrors: bool = True
) -> Optional[Failure]:
"""Creates a function suitable for passing to `Deferred.addErrback` that
logs any failures that occur.
Args:
failure: The Failure to log
msg: Message to log
consumeErrors: If true consumes the failure, otherwise passes on down
the callback chain
Returns:
The Failure if consumeErrors is false. None, otherwise.
"""
logger.error(
msg, exc_info=(failure.type, failure.value, failure.getTracebackObject()) # type: ignore[arg-type]
)
if not consumeErrors:
return failure
return None
# Version string with git info. Computed here once so that we don't invoke git multiple
# times.
SYNAPSE_VERSION = get_distribution_version_string("matrix-synapse", __file__)