summary refs log tree commit diff
path: root/synapse/util/__init__.py
blob: 756d8ffa323e0ae2f855abed3d60d4a3c0994805 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# 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.

from synapse.api.errors import SynapseError
from synapse.util.logcontext import PreserveLoggingContext

from twisted.internet import defer, reactor, task

import time
import logging

logger = logging.getLogger(__name__)


class DeferredTimedOutError(SynapseError):
    def __init__(self):
        super(DeferredTimedOutError, self).__init__(504, "Timed out")


def unwrapFirstError(failure):
    # defer.gatherResults and DeferredLists wrap failures.
    failure.trap(defer.FirstError)
    return failure.value.subFailure


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
    """

    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."""
        return int(self.time() * 1000)

    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

    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):
            with PreserveLoggingContext():
                callback(*args, **kwargs)

        with PreserveLoggingContext():
            return reactor.callLater(delay, wrapped_callback, *args, **kwargs)

    def cancel_call_later(self, timer, ignore_errs=False):
        try:
            timer.cancel()
        except Exception:
            if not ignore_errs:
                raise

    def time_bound_deferred(self, given_deferred, time_out):
        if given_deferred.called:
            return given_deferred

        ret_deferred = defer.Deferred()

        def timed_out_fn():
            e = DeferredTimedOutError()

            try:
                ret_deferred.errback(e)
            except Exception:
                pass

            try:
                given_deferred.cancel()
            except Exception:
                pass

        timer = None

        def cancel(res):
            try:
                self.cancel_call_later(timer)
            except Exception:
                pass
            return res

        ret_deferred.addBoth(cancel)

        def success(res):
            try:
                ret_deferred.callback(res)
            except Exception:
                pass

            return res

        def err(res):
            try:
                ret_deferred.errback(res)
            except Exception:
                pass

        given_deferred.addCallbacks(callback=success, errback=err)

        timer = self.call_later(time_out, timed_out_fn)

        return ret_deferred