debian-billiard/billiard/common.py

135 lines
3.6 KiB
Python

# -*- coding: utf-8 -*-
"""
This module contains utilities added by billiard, to keep
"non-core" functionality out of ``.util``."""
from __future__ import absolute_import
import os
import signal
import sys
import pickle as pypickle
try:
import cPickle as cpickle
except ImportError: # pragma: no cover
cpickle = None # noqa
from .exceptions import RestartFreqExceeded
from .five import monotonic
if sys.version_info < (2, 6): # pragma: no cover
# cPickle does not use absolute_imports
pickle = pypickle
pickle_load = pypickle.load
pickle_loads = pypickle.loads
else:
pickle = cpickle or pypickle
pickle_load = pickle.load
pickle_loads = pickle.loads
# cPickle.loads does not support buffer() objects,
# but we can just create a StringIO and use load.
if sys.version_info[0] == 3:
from io import BytesIO
else:
try:
from cStringIO import StringIO as BytesIO # noqa
except ImportError:
from StringIO import StringIO as BytesIO # noqa
EX_SOFTWARE = 70
TERMSIGS_DEFAULT = (
'SIGHUP',
'SIGQUIT',
'SIGTERM',
'SIGUSR1',
'SIGUSR2'
)
TERMSIGS_FULL = (
'SIGHUP',
'SIGQUIT',
'SIGTRAP',
'SIGABRT',
'SIGEMT',
'SIGSYS',
'SIGPIPE',
'SIGALRM',
'SIGTERM',
'SIGXCPU',
'SIGXFSZ',
'SIGVTALRM',
'SIGPROF',
'SIGUSR1',
'SIGUSR2',
)
#: set by signal handlers just before calling exit.
#: if this is true after the sighandler returns it means that something
#: went wrong while terminating the process, and :func:`os._exit`
#: must be called ASAP.
_should_have_exited = [False]
def pickle_loads(s, load=pickle_load):
# used to support buffer objects
return load(BytesIO(s))
def maybe_setsignal(signum, handler):
try:
signal.signal(signum, handler)
except (OSError, AttributeError, ValueError, RuntimeError):
pass
def _shutdown_cleanup(signum, frame):
# we will exit here so if the signal is received a second time
# we can be sure that something is very wrong and we may be in
# a crashing loop.
if _should_have_exited[0]:
os._exit(EX_SOFTWARE)
maybe_setsignal(signum, signal.SIG_DFL)
_should_have_exited[0] = True
sys.exit(-(256 - signum))
def reset_signals(handler=_shutdown_cleanup, full=False):
for sig in TERMSIGS_FULL if full else TERMSIGS_DEFAULT:
try:
signum = getattr(signal, sig)
except AttributeError:
pass
else:
current = signal.getsignal(signum)
if current is not None and current != signal.SIG_IGN:
maybe_setsignal(signum, handler)
class restart_state(object):
RestartFreqExceeded = RestartFreqExceeded
def __init__(self, maxR, maxT):
self.maxR, self.maxT = maxR, maxT
self.R, self.T = 0, None
def step(self, now=None):
now = monotonic() if now is None else now
R = self.R
if self.T and now - self.T >= self.maxT:
# maxT passed, reset counter and time passed.
self.T, self.R = now, 0
elif self.maxR and self.R >= self.maxR:
# verify that R has a value as the result handler
# resets this when a job is accepted. If a job is accepted
# the startup probably went fine (startup restart burst
# protection)
if self.R: # pragma: no cover
self.R = 0 # reset in case someone catches the error
raise self.RestartFreqExceeded("%r in %rs" % (R, self.maxT))
# first run sets T
if self.T is None:
self.T = now
self.R += 1