synapse-old/synapse/util/__init__.py

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# -*- coding: utf-8 -*-
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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.
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from synapse.util.logcontext import PreserveLoggingContext
from twisted.internet import defer, reactor, task
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import time
import logging
from itertools import islice
logger = logging.getLogger(__name__)
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def unwrapFirstError(failure):
# defer.gatherResults and DeferredLists wrap failures.
failure.trap(defer.FirstError)
return failure.value.subFailure
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class Clock(object):
"""A small utility that obtains current time-of-day so that time may be
mocked during unit-tests.
TODO(paul): Also move the sleep() functionality into it
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"""
def time(self):
"""Returns the current system time in seconds since epoch."""
return time.time()
def time_msec(self):
"""Returns the current system time in miliseconds since epoch."""
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return int(self.time() * 1000)
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def looping_call(self, f, msec):
"""Call a function repeatedly.
Waits `msec` initially before calling `f` for the first time.
Args:
f(function): The function to call repeatedly.
msec(float): How long to wait between calls in milliseconds.
"""
call = task.LoopingCall(f)
call.start(msec / 1000.0, now=False)
return call
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def call_later(self, delay, callback, *args, **kwargs):
"""Call something later
Args:
delay(float): How long to wait in seconds.
callback(function): Function to call
*args: Postional arguments to pass to function.
**kwargs: Key arguments to pass to function.
"""
def wrapped_callback(*args, **kwargs):
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with PreserveLoggingContext():
callback(*args, **kwargs)
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with PreserveLoggingContext():
return reactor.callLater(delay, wrapped_callback, *args, **kwargs)
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def cancel_call_later(self, timer, ignore_errs=False):
try:
timer.cancel()
except Exception:
if not ignore_errs:
raise
def batch_iter(iterable, size):
"""batch an iterable up into tuples with a maximum size
Args:
iterable (iterable): the iterable to slice
size (int): the maximum batch size
Returns:
an iterator over the chunks
"""
# make sure we can deal with iterables like lists too
sourceiter = iter(iterable)
# call islice until it returns an empty tuple
return iter(lambda: tuple(islice(sourceiter, size)), ())