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##############################################################################
# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
# Produced at the Lawrence Livermore National Laboratory.
#
# This file is part of Spack.
# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
# LLNL-CODE-647188
#
# For details, see https://github.com/llnl/spack
# Please also see the LICENSE file for our notice and the LGPL.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License (as published by
# the Free Software Foundation) version 2.1 dated February 1999.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
# conditions of the GNU General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##############################################################################
"""
These tests ensure that our lock works correctly.
"""
import unittest
import os
import tempfile
import shutil
from multiprocessing import Process
from llnl.util.lock import *
from llnl.util.filesystem import join_path, touch
from spack.util.multiproc import Barrier
# This is the longest a failed test will take, as the barriers will
# time out and raise an exception.
barrier_timeout = 5
class LockTest(unittest.TestCase):
def setUp(self):
self.tempdir = tempfile.mkdtemp()
self.lock_path = join_path(self.tempdir, 'lockfile')
touch(self.lock_path)
def tearDown(self):
shutil.rmtree(self.tempdir, ignore_errors=True)
def multiproc_test(self, *functions):
"""Order some processes using simple barrier synchronization."""
b = Barrier(len(functions), timeout=barrier_timeout)
procs = [Process(target=f, args=(b,)) for f in functions]
for p in procs: p.start()
for p in procs:
p.join()
self.assertEqual(p.exitcode, 0)
#
# Process snippets below can be composed into tests.
#
def acquire_write(self, barrier):
lock = Lock(self.lock_path)
lock.acquire_write() # grab exclusive lock
barrier.wait()
barrier.wait() # hold the lock until exception raises in other procs.
def acquire_read(self, barrier):
lock = Lock(self.lock_path)
lock.acquire_read() # grab shared lock
barrier.wait()
barrier.wait() # hold the lock until exception raises in other procs.
def timeout_write(self, barrier):
lock = Lock(self.lock_path)
barrier.wait() # wait for lock acquire in first process
self.assertRaises(LockError, lock.acquire_write, 0.1)
barrier.wait()
def timeout_read(self, barrier):
lock = Lock(self.lock_path)
barrier.wait() # wait for lock acquire in first process
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait()
#
# Test that exclusive locks on other processes time out when an
# exclusive lock is held.
#
def test_write_lock_timeout_on_write(self):
self.multiproc_test(self.acquire_write, self.timeout_write)
def test_write_lock_timeout_on_write_2(self):
self.multiproc_test(self.acquire_write, self.timeout_write, self.timeout_write)
def test_write_lock_timeout_on_write_3(self):
self.multiproc_test(self.acquire_write, self.timeout_write, self.timeout_write, self.timeout_write)
#
# Test that shared locks on other processes time out when an
# exclusive lock is held.
#
def test_read_lock_timeout_on_write(self):
self.multiproc_test(self.acquire_write, self.timeout_read)
def test_read_lock_timeout_on_write_2(self):
self.multiproc_test(self.acquire_write, self.timeout_read, self.timeout_read)
def test_read_lock_timeout_on_write_3(self):
self.multiproc_test(self.acquire_write, self.timeout_read, self.timeout_read, self.timeout_read)
#
# Test that exclusive locks time out when shared locks are held.
#
def test_write_lock_timeout_on_read(self):
self.multiproc_test(self.acquire_read, self.timeout_write)
def test_write_lock_timeout_on_read_2(self):
self.multiproc_test(self.acquire_read, self.timeout_write, self.timeout_write)
def test_write_lock_timeout_on_read_3(self):
self.multiproc_test(self.acquire_read, self.timeout_write, self.timeout_write, self.timeout_write)
#
# Test that exclusive locks time while lots of shared locks are held.
#
def test_write_lock_timeout_with_multiple_readers_2_1(self):
self.multiproc_test(self.acquire_read, self.acquire_read, self.timeout_write)
def test_write_lock_timeout_with_multiple_readers_2_2(self):
self.multiproc_test(self.acquire_read, self.acquire_read, self.timeout_write, self.timeout_write)
def test_write_lock_timeout_with_multiple_readers_3_1(self):
self.multiproc_test(self.acquire_read, self.acquire_read, self.acquire_read, self.timeout_write)
def test_write_lock_timeout_with_multiple_readers_3_2(self):
self.multiproc_test(self.acquire_read, self.acquire_read, self.acquire_read, self.timeout_write, self.timeout_write)
#
# Longer test case that ensures locks are reusable. Ordering is
# enforced by barriers throughout -- steps are shown with numbers.
#
def test_complex_acquire_and_release_chain(self):
def p1(barrier):
lock = Lock(self.lock_path)
lock.acquire_write()
barrier.wait() # ---------------------------------------- 1
# others test timeout
barrier.wait() # ---------------------------------------- 2
lock.release_write() # release and others acquire read
barrier.wait() # ---------------------------------------- 3
self.assertRaises(LockError, lock.acquire_write, 0.1)
lock.acquire_read()
barrier.wait() # ---------------------------------------- 4
lock.release_read()
barrier.wait() # ---------------------------------------- 5
# p2 upgrades read to write
barrier.wait() # ---------------------------------------- 6
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 7
# p2 releases write and read
barrier.wait() # ---------------------------------------- 8
# p3 acquires read
barrier.wait() # ---------------------------------------- 9
# p3 upgrades read to write
barrier.wait() # ---------------------------------------- 10
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 11
# p3 releases locks
barrier.wait() # ---------------------------------------- 12
lock.acquire_read()
barrier.wait() # ---------------------------------------- 13
lock.release_read()
def p2(barrier):
lock = Lock(self.lock_path)
# p1 acquires write
barrier.wait() # ---------------------------------------- 1
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 2
lock.acquire_read()
barrier.wait() # ---------------------------------------- 3
# p1 tests shared read
barrier.wait() # ---------------------------------------- 4
# others release reads
barrier.wait() # ---------------------------------------- 5
lock.acquire_write() # upgrade read to write
barrier.wait() # ---------------------------------------- 6
# others test timeout
barrier.wait() # ---------------------------------------- 7
lock.release_write() # release read AND write (need both)
lock.release_read()
barrier.wait() # ---------------------------------------- 8
# p3 acquires read
barrier.wait() # ---------------------------------------- 9
# p3 upgrades read to write
barrier.wait() # ---------------------------------------- 10
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 11
# p3 releases locks
barrier.wait() # ---------------------------------------- 12
lock.acquire_read()
barrier.wait() # ---------------------------------------- 13
lock.release_read()
def p3(barrier):
lock = Lock(self.lock_path)
# p1 acquires write
barrier.wait() # ---------------------------------------- 1
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 2
lock.acquire_read()
barrier.wait() # ---------------------------------------- 3
# p1 tests shared read
barrier.wait() # ---------------------------------------- 4
lock.release_read()
barrier.wait() # ---------------------------------------- 5
# p2 upgrades read to write
barrier.wait() # ---------------------------------------- 6
self.assertRaises(LockError, lock.acquire_write, 0.1)
self.assertRaises(LockError, lock.acquire_read, 0.1)
barrier.wait() # ---------------------------------------- 7
# p2 releases write & read
barrier.wait() # ---------------------------------------- 8
lock.acquire_read()
barrier.wait() # ---------------------------------------- 9
lock.acquire_write()
barrier.wait() # ---------------------------------------- 10
# others test timeout
barrier.wait() # ---------------------------------------- 11
lock.release_read() # release read AND write in opposite
lock.release_write() # order from before on p2
barrier.wait() # ---------------------------------------- 12
lock.acquire_read()
barrier.wait() # ---------------------------------------- 13
lock.release_read()
self.multiproc_test(p1, p2, p3)
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