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
|
# -*- coding: utf-8 -*-
from __future__ import (absolute_import, division, print_function,
unicode_literals)
import signal
class BaseTimeoutException(Exception):
"""Base exception for timeouts."""
pass
class JobTimeoutException(BaseTimeoutException):
"""Raised when a job takes longer to complete than the allowed maximum
timeout value.
"""
pass
class HorseMonitorTimeoutException(BaseTimeoutException):
"""Raised when waiting for a horse exiting takes longer than the maximum
timeout value.
"""
pass
class BaseDeathPenalty(object):
"""Base class to setup job timeouts."""
def __init__(self, timeout, exception=JobTimeoutException, **kwargs):
self._timeout = timeout
self._exception = exception
def __enter__(self):
self.setup_death_penalty()
def __exit__(self, type, value, traceback):
# Always cancel immediately, since we're done
try:
self.cancel_death_penalty()
except BaseTimeoutException:
# Weird case: we're done with the with body, but now the alarm is
# fired. We may safely ignore this situation and consider the
# body done.
pass
# __exit__ may return True to supress further exception handling. We
# don't want to suppress any exceptions here, since all errors should
# just pass through, BaseTimeoutException being handled normally to the
# invoking context.
return False
def setup_death_penalty(self):
raise NotImplementedError()
def cancel_death_penalty(self):
raise NotImplementedError()
class UnixSignalDeathPenalty(BaseDeathPenalty):
def handle_death_penalty(self, signum, frame):
raise self._exception('Task exceeded maximum timeout value '
'({0} seconds)'.format(self._timeout))
def setup_death_penalty(self):
"""Sets up an alarm signal and a signal handler that raises
an exception after the timeout amount (expressed in seconds).
"""
signal.signal(signal.SIGALRM, self.handle_death_penalty)
signal.alarm(self._timeout)
def cancel_death_penalty(self):
"""Removes the death penalty alarm and puts back the system into
default signal handling.
"""
signal.alarm(0)
signal.signal(signal.SIGALRM, signal.SIG_DFL)
|
