152 lines
4.7 KiB
Python
Executable File
152 lines
4.7 KiB
Python
Executable File
#!/usr/bin/python3 -u
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"""
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Allocates resources from a lock directory with flock and/or a make jobserver while running
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some command.
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"""
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import time
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import os
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import re
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import subprocess
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import fcntl
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import signal
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from optparse import OptionParser
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usage = "usage: %prog [options] [--] command arg1 arg2 ..."
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parser = OptionParser(usage=usage)
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parser.add_option("-r", "--resource",
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dest="resources",
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action="append",
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help="Name of a resource which gets locked while running the command.")
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parser.add_option("-j", "--jobs",
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default=1,
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type='int',
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action="store",
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help="Number of jobs to allocate from job server. Ignored if not running under a job server.")
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(options, args) = parser.parse_args()
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def log(format, *args):
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now = time.time()
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print(time.asctime(time.gmtime(now)), 'UTC', '(+ %.1fs / %.1fs)' % (now - log.latest, now - log.start), format % args)
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log.latest = now
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log.start = time.time()
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log.latest = log.start
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# As a first step, lock one resource named like the
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# test before running the test.
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gobject = None
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if options.resources:
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# Support mapping of resource "foo" to "bar" with RESOURCES_FOO=bar.
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resources = []
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for name in options.resources:
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replacement = os.environ.get('RESOURCES_%s' % name.upper(), None)
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if replacement is not None:
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resources.extend(replacement.split(','))
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else:
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resources.append(name)
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if resources != options.resources:
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log('replaced resource set %s with %s based on RESOURCES_* env vars', options.resources, resources)
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if resources:
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log('=== locking resource(s) %s ===', resources)
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lockdir = os.environ.get('RESOURCES_DIR', None)
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if lockdir is None:
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log('RESOURCES_DIR env var not set')
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exit(1)
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for resource in resources:
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log('locking resource %s' % resource)
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start = time.time()
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# If the resource doesn't exist, we don't need to lock it.
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path = os.path.join(lockdir, resource)
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if os.path.exists(path):
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f = open(path, "w")
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fcntl.lockf(f, fcntl.LOCK_EX)
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end = time.time()
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log('locked resource %s, delay %ds' % (resource, end - start))
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else:
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log('resource %s needs no lock' % resource)
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class Jobserver:
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'''Allocates the given number of job slots from the "make -j"
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jobserver, then runs the command and finally returns the slots.
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See http://mad-scientist.net/make/jobserver.html'''
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def __init__(self):
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self.havejobserver = False
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self.allocated = 0
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# MAKEFLAGS= --jobserver-fds=3,4 -j
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flags = os.environ.get('MAKEFLAGS', '')
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m = re.search(r'--jobserver-fds=(\d+),(\d+)', flags)
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if m:
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self.receiveslots = int(m.group(1))
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self.returnslots = int(m.group(2))
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self.blocked = {}
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self.havejobserver = True
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log('using jobserver')
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else:
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log('not using jobserver')
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def active(self):
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return self.havejobserver
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def alloc(self, numjobs = 1):
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if not self.havejobserver:
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return
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n = 0
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self._block()
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try:
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while n < numjobs:
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os.read(self.receiveslots, 1)
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n += 1
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self.allocated += n
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n = 0
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except:
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os.write(self.returnslots, b' ' * n)
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raise
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finally:
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self._unblock()
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def free(self, numjobs = 1):
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if not self.havejobserver:
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return
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try:
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self.allocated -= numjobs
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os.write(self.returnslots, b' ' * numjobs)
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finally:
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self._unblock()
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def _block(self):
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'''Block signals if not already done.'''
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if not self.blocked:
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for sig in [ signal.SIGINT, signal.SIGTERM ]:
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self.blocked[sig] = signal.signal(sig, signal.SIG_IGN)
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def _unblock(self):
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'''Unblock signals if blocked and we currently own no slots.'''
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if self.blocked and not self.allocated:
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for sig, handler in self.blocked.items():
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signal.signal(sig, handler)
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self.blocked = {}
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jobserver = Jobserver()
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jobs = 0
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if jobserver.active() and options.jobs:
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log('=== allocating %d job slot(s) ===', options.jobs)
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jobserver.alloc(options.jobs)
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log('=== allocated %d job slot(s) ===', options.jobs)
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jobs = options.jobs
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try:
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subprocess.check_call(args)
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finally:
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log('=== cleaning up ===')
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# Return job tokens.
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if jobs:
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jobserver.free(jobs)
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# We don't need to unlock the resources. Quitting will do
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# that automatically.
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