Synnefo » snf-ganeti

#!/usr/bin/python

#

# Copyright (C) 2006, 2007 Google Inc.

#

# 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; either version 2 of the License, or

# (at your option) any later version.

#

# 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 GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 0.0510-1301, USA.

"""Script for unittesting the locking module"""

import os

import unittest

import time

import Queue

import threading

from ganeti import locking

from ganeti import errors

# This is used to test the ssynchronize decorator.

# Since it's passed as input to a decorator it must be declared as a global.

_decoratorlock = locking.SharedLock()

#: List for looping tests

ITERATIONS = range(8)

def _Repeat(fn):

  """Decorator for executing a function many times"""

  def wrapper(*args, **kwargs):

    for i in ITERATIONS:

      fn(*args, **kwargs)

  return wrapper

class _ThreadedTestCase(unittest.TestCase):

  """Test class that supports adding/waiting on threads"""

  def setUp(self):

    unittest.TestCase.setUp(self)

    self.threads = []

  def _addThread(self, *args, **kwargs):

    """Create and remember a new thread"""

    t = threading.Thread(*args, **kwargs)

    self.threads.append(t)

    t.start()

    return t

  def _waitThreads(self):

    """Wait for all our threads to finish"""

    for t in self.threads:

      t.join(60)

      self.failIf(t.isAlive())

    self.threads = []

class TestSharedLock(_ThreadedTestCase):

  """SharedLock tests"""

  def setUp(self):

    _ThreadedTestCase.setUp(self)

    self.sl = locking.SharedLock()

    # helper threads use the 'done' queue to tell the master they finished.

    self.done = Queue.Queue(0)

  def testSequenceAndOwnership(self):

    self.assert_(not self.sl._is_owned())

    self.sl.acquire(shared=1)

    self.assert_(self.sl._is_owned())

    self.assert_(self.sl._is_owned(shared=1))

    self.assert_(not self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

    self.sl.acquire()

    self.assert_(self.sl._is_owned())

    self.assert_(not self.sl._is_owned(shared=1))

    self.assert_(self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

    self.sl.acquire(shared=1)

    self.assert_(self.sl._is_owned())

    self.assert_(self.sl._is_owned(shared=1))

    self.assert_(not self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

  def testBooleanValue(self):

    # semaphores are supposed to return a true value on a successful acquire

    self.assert_(self.sl.acquire(shared=1))

    self.sl.release()

    self.assert_(self.sl.acquire())

    self.sl.release()

  def testDoubleLockingStoE(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.acquire)

  def testDoubleLockingEtoS(self):

    self.sl.acquire()

    self.assertRaises(AssertionError, self.sl.acquire, shared=1)

  def testDoubleLockingStoS(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.acquire, shared=1)

  def testDoubleLockingEtoE(self):

    self.sl.acquire()

    self.assertRaises(AssertionError, self.sl.acquire)

  # helper functions: called in a separate thread they acquire the lock, send

  # their identifier on the done queue, then release it.

  def _doItSharer(self):

    try:

      self.sl.acquire(shared=1)

      self.done.put('SHR')

      self.sl.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doItExclusive(self):

    try:

      self.sl.acquire()

      self.done.put('EXC')

      self.sl.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doItDelete(self):

    try:

      self.sl.delete()

      self.done.put('DEL')

    except errors.LockError:

      self.done.put('ERR')

  def testSharersCanCoexist(self):

    self.sl.acquire(shared=1)

    threading.Thread(target=self._doItSharer).start()

    self.assert_(self.done.get(True, 1))

    self.sl.release()

  @_Repeat

  def testExclusiveBlocksExclusive(self):

    self.sl.acquire()

    self._addThread(target=self._doItExclusive)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'EXC')

  @_Repeat

  def testExclusiveBlocksDelete(self):

    self.sl.acquire()

    self._addThread(target=self._doItDelete)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'DEL')

    self.sl = locking.SharedLock()

  @_Repeat

  def testExclusiveBlocksSharer(self):

    self.sl.acquire()

    self._addThread(target=self._doItSharer)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'SHR')

  @_Repeat

  def testSharerBlocksExclusive(self):

    self.sl.acquire(shared=1)

    self._addThread(target=self._doItExclusive)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'EXC')

  @_Repeat

  def testSharerBlocksDelete(self):

    self.sl.acquire(shared=1)

    self._addThread(target=self._doItDelete)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'DEL')

    self.sl = locking.SharedLock()

  @_Repeat

  def testWaitingExclusiveBlocksSharer(self):

    """SKIPPED testWaitingExclusiveBlockSharer"""

    return

    self.sl.acquire(shared=1)

    # the lock is acquired in shared mode...

    self._addThread(target=self._doItExclusive)

    # ...but now an exclusive is waiting...

    self._addThread(target=self._doItSharer)

    # ...so the sharer should be blocked as well

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    # The exclusive passed before

    self.failUnlessEqual(self.done.get_nowait(), 'EXC')

    self.failUnlessEqual(self.done.get_nowait(), 'SHR')

  @_Repeat

  def testWaitingSharerBlocksExclusive(self):

    """SKIPPED testWaitingSharerBlocksExclusive"""

    return

    self.sl.acquire()

    # the lock is acquired in exclusive mode...

    self._addThread(target=self._doItSharer)

    # ...but now a sharer is waiting...

    self._addThread(target=self._doItExclusive)

    # ...the exclusive is waiting too...

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    self.sl.release()

    self._waitThreads()

    # The sharer passed before

    self.assertEqual(self.done.get_nowait(), 'SHR')

    self.assertEqual(self.done.get_nowait(), 'EXC')

  def testDelete(self):

    self.sl.delete()

    self.assertRaises(errors.LockError, self.sl.acquire)

    self.assertRaises(errors.LockError, self.sl.acquire, shared=1)

    self.assertRaises(errors.LockError, self.sl.delete)

  def testNoDeleteIfSharer(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.delete)

  @_Repeat

  def testDeletePendingSharersExclusiveDelete(self):

    self.sl.acquire()

    self._addThread(target=self._doItSharer)

    self._addThread(target=self._doItSharer)

    self._addThread(target=self._doItExclusive)

    self._addThread(target=self._doItDelete)

    self.sl.delete()

    self._waitThreads()

    # The threads who were pending return ERR

    for _ in range(4):

      self.assertEqual(self.done.get_nowait(), 'ERR')

    self.sl = locking.SharedLock()

  @_Repeat

  def testDeletePendingDeleteExclusiveSharers(self):

    self.sl.acquire()

    self._addThread(target=self._doItDelete)

    self._addThread(target=self._doItExclusive)

    self._addThread(target=self._doItSharer)

    self._addThread(target=self._doItSharer)

    self.sl.delete()

    self._waitThreads()

    # The two threads who were pending return both ERR

    self.assertEqual(self.done.get_nowait(), 'ERR')

    self.assertEqual(self.done.get_nowait(), 'ERR')

    self.assertEqual(self.done.get_nowait(), 'ERR')

    self.assertEqual(self.done.get_nowait(), 'ERR')

    self.sl = locking.SharedLock()

  @_Repeat

  def testExclusiveAcquireTimeout(self):

    def _LockExclusive(wait):

      self.sl.acquire(shared=0)

      self.done.put("A: start sleep")

      time.sleep(wait)

      self.done.put("A: end sleep")

      self.sl.release()

    for shared in [0, 1]:

      # Start thread to hold lock for 20 ms

      self._addThread(target=_LockExclusive, args=(20.0 / 1000.0, ))

      # Wait up to 100 ms to get lock

      self.failUnless(self.sl.acquire(shared=shared, timeout=0.1))

      self.done.put("got 2nd")

      self.sl.release()

      self._waitThreads()

      self.assertEqual(self.done.get_nowait(), "A: start sleep")

      self.assertEqual(self.done.get_nowait(), "A: end sleep")

      self.assertEqual(self.done.get_nowait(), "got 2nd")

      self.assertRaises(Queue.Empty, self.done.get_nowait)

  @_Repeat

  def testAcquireExpiringTimeout(self):

    def _AcquireWithTimeout(shared, timeout):

      if not self.sl.acquire(shared=shared, timeout=timeout):

        self.done.put("timeout")

    for shared in [0, 1]:

      # Lock exclusively

      self.sl.acquire()

      # Start shared acquires with timeout between 0 and 20 ms

      for i in xrange(11):

        self._addThread(target=_AcquireWithTimeout,

                        args=(shared, i * 2.0 / 1000.0))

      # Wait for threads to finish (makes sure the acquire timeout expires

      # before releasing the lock)

      self._waitThreads()

      # Release lock

      self.sl.release()

      for _ in xrange(11):

        self.assertEqual(self.done.get_nowait(), "timeout")

      self.assertRaises(Queue.Empty, self.done.get_nowait)

  @_Repeat

  def testSharedSkipExclusiveAcquires(self):

    # Tests whether shared acquires jump in front of exclusive acquires in the

    # queue.

    # Get exclusive lock while we fill the queue

    self.sl.acquire()

    def _Acquire(shared, name):

      if not self.sl.acquire(shared=shared):

        return

      self.done.put(name)

      self.sl.release()

    # Start shared acquires

    for _ in xrange(5):

      self._addThread(target=_Acquire, args=(1, "shared A"))

    # Start exclusive acquires

    for _ in xrange(3):

      self._addThread(target=_Acquire, args=(0, "exclusive B"))

    # More shared acquires

    for _ in xrange(5):

      self._addThread(target=_Acquire, args=(1, "shared C"))

    # More exclusive acquires

    for _ in xrange(3):

      self._addThread(target=_Acquire, args=(0, "exclusive D"))

    # Expect 6 pending exclusive acquires and 1 for all shared acquires

    # together

    self.assertEqual(self.sl._count_pending(), 7)

    # Release exclusive lock and wait

    self.sl.release()

    self._waitThreads()

    # Check sequence

    for _ in xrange(10):

      # Shared locks aren't guaranteed to be notified in order, but they'll be

      # first

      self.assert_(self.done.get_nowait() in ("shared A", "shared C"))

    for _ in xrange(3):

      self.assertEqual(self.done.get_nowait(), "exclusive B")

    for _ in xrange(3):

      self.assertEqual(self.done.get_nowait(), "exclusive D")

    self.assertRaises(Queue.Empty, self.done.get_nowait)

  @_Repeat

  def testMixedAcquireTimeout(self):

    sync = threading.Condition()

    def _AcquireShared(ev):

      if not self.sl.acquire(shared=1, timeout=None):

        return

      self.done.put("shared")

      # Notify main thread

      ev.set()

      # Wait for notification

      sync.acquire()

      try:

        sync.wait()

      finally:

        sync.release()

      # Release lock

      self.sl.release()

    acquires = []

    for _ in xrange(3):

      ev = threading.Event()

      self._addThread(target=_AcquireShared, args=(ev, ))

      acquires.append(ev)

    # Wait for all acquires to finish

    for i in acquires:

      i.wait()

    self.assertEqual(self.sl._count_pending(), 0)

    # Try to get exclusive lock

    self.failIf(self.sl.acquire(shared=0, timeout=0.02))

    # Acquire exclusive without timeout

    exclsync = threading.Condition()

    exclev = threading.Event()

    def _AcquireExclusive():

      if not self.sl.acquire(shared=0):

        return

      self.done.put("exclusive")

      # Notify main thread

      exclev.set()

      exclsync.acquire()

      try:

        exclsync.wait()

      finally:

        exclsync.release()

      self.sl.release()

    self._addThread(target=_AcquireExclusive)

    # Try to get exclusive lock

    self.failIf(self.sl.acquire(shared=0, timeout=0.02))

    # Make all shared holders release their locks

    sync.acquire()

    try:

      sync.notifyAll()

    finally:

      sync.release()

    # Wait for exclusive acquire to succeed

    exclev.wait()

    self.assertEqual(self.sl._count_pending(), 0)

    # Try to get exclusive lock

    self.failIf(self.sl.acquire(shared=0, timeout=0.02))

    def _AcquireSharedSimple():

      if self.sl.acquire(shared=1, timeout=None):

        self.done.put("shared2")

        self.sl.release()

    for _ in xrange(10):

      self._addThread(target=_AcquireSharedSimple)

    # Tell exclusive lock to release

    exclsync.acquire()

    try:

      exclsync.notifyAll()

    finally:

      exclsync.release()

    # Wait for everything to finish

    self._waitThreads()

    self.assertEqual(self.sl._count_pending(), 0)

    # Check sequence

    for _ in xrange(3):

      self.assertEqual(self.done.get_nowait(), "shared")

    self.assertEqual(self.done.get_nowait(), "exclusive")

    for _ in xrange(10):

      self.assertEqual(self.done.get_nowait(), "shared2")

    self.assertRaises(Queue.Empty, self.done.get_nowait)

class TestSSynchronizedDecorator(_ThreadedTestCase):

  """Shared Lock Synchronized decorator test"""

  def setUp(self):

    _ThreadedTestCase.setUp(self)

    # helper threads use the 'done' queue to tell the master they finished.

    self.done = Queue.Queue(0)

  @locking.ssynchronized(_decoratorlock)

  def _doItExclusive(self):

    self.assert_(_decoratorlock._is_owned())

    self.done.put('EXC')

  @locking.ssynchronized(_decoratorlock, shared=1)

  def _doItSharer(self):

    self.assert_(_decoratorlock._is_owned(shared=1))

    self.done.put('SHR')

  def testDecoratedFunctions(self):

    self._doItExclusive()

    self.assert_(not _decoratorlock._is_owned())

    self._doItSharer()

    self.assert_(not _decoratorlock._is_owned())

  def testSharersCanCoexist(self):

    _decoratorlock.acquire(shared=1)

    threading.Thread(target=self._doItSharer).start()

    self.assert_(self.done.get(True, 1))

    _decoratorlock.release()

  @_Repeat

  def testExclusiveBlocksExclusive(self):

    _decoratorlock.acquire()

    self._addThread(target=self._doItExclusive)

    # give it a bit of time to check that it's not actually doing anything

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    _decoratorlock.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'EXC')

  @_Repeat

  def testExclusiveBlocksSharer(self):

    _decoratorlock.acquire()

    self._addThread(target=self._doItSharer)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    _decoratorlock.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'SHR')

  @_Repeat

  def testSharerBlocksExclusive(self):

    _decoratorlock.acquire(shared=1)

    self._addThread(target=self._doItExclusive)

    self.assertRaises(Queue.Empty, self.done.get_nowait)

    _decoratorlock.release()

    self._waitThreads()

    self.failUnlessEqual(self.done.get_nowait(), 'EXC')

class TestLockSet(_ThreadedTestCase):

  """LockSet tests"""

  def setUp(self):

    _ThreadedTestCase.setUp(self)

    self._setUpLS()

    # helper threads use the 'done' queue to tell the master they finished.

    self.done = Queue.Queue(0)

  def _setUpLS(self):

    """Helper to (re)initialize the lock set"""

    self.resources = ['one', 'two', 'three']

    self.ls = locking.LockSet(members=self.resources)

  def testResources(self):

    self.assertEquals(self.ls._names(), set(self.resources))

    newls = locking.LockSet()

    self.assertEquals(newls._names(), set())

  def testAcquireRelease(self):

    self.assert_(self.ls.acquire('one'))

    self.assertEquals(self.ls._list_owned(), set(['one']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.assertEquals(self.ls.acquire(['one']), set(['one']))

    self.assertEquals(self.ls._list_owned(), set(['one']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.ls.acquire(['one', 'two', 'three'])

    self.assertEquals(self.ls._list_owned(), set(['one', 'two', 'three']))

    self.ls.release('one')

    self.assertEquals(self.ls._list_owned(), set(['two', 'three']))

    self.ls.release(['three'])

    self.assertEquals(self.ls._list_owned(), set(['two']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.assertEquals(self.ls.acquire(['one', 'three']), set(['one', 'three']))

    self.assertEquals(self.ls._list_owned(), set(['one', 'three']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

  def testNoDoubleAcquire(self):

    self.ls.acquire('one')

    self.assertRaises(AssertionError, self.ls.acquire, 'one')

    self.assertRaises(AssertionError, self.ls.acquire, ['two'])

    self.assertRaises(AssertionError, self.ls.acquire, ['two', 'three'])

    self.ls.release()

    self.ls.acquire(['one', 'three'])

    self.ls.release('one')

    self.assertRaises(AssertionError, self.ls.acquire, ['two'])

    self.ls.release('three')

  def testNoWrongRelease(self):

    self.assertRaises(AssertionError, self.ls.release)

    self.ls.acquire('one')

    self.assertRaises(AssertionError, self.ls.release, 'two')

  def testAddRemove(self):

    self.ls.add('four')

    self.assertEquals(self.ls._list_owned(), set())

    self.assert_('four' in self.ls._names())

    self.ls.add(['five', 'six', 'seven'], acquired=1)

    self.assert_('five' in self.ls._names())

    self.assert_('six' in self.ls._names())

    self.assert_('seven' in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['five', 'six', 'seven']))

    self.assertEquals(self.ls.remove(['five', 'six']), ['five', 'six'])

    self.assert_('five' not in self.ls._names())

    self.assert_('six' not in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['seven']))

    self.assertRaises(AssertionError, self.ls.add, 'eight', acquired=1)

    self.ls.remove('seven')

    self.assert_('seven' not in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set([]))

    self.ls.acquire(None, shared=1)

    self.assertRaises(AssertionError, self.ls.add, 'eight')

    self.ls.release()

    self.ls.acquire(None)

    self.ls.add('eight', acquired=1)

    self.assert_('eight' in self.ls._names())

    self.assert_('eight' in self.ls._list_owned())

    self.ls.add('nine')

    self.assert_('nine' in self.ls._names())

    self.assert_('nine' not in self.ls._list_owned())

    self.ls.release()

    self.ls.remove(['two'])

    self.assert_('two' not in self.ls._names())

    self.ls.acquire('three')

    self.assertEquals(self.ls.remove(['three']), ['three'])

    self.assert_('three' not in self.ls._names())

    self.assertEquals(self.ls.remove('three'), [])

    self.assertEquals(self.ls.remove(['one', 'three', 'six']), ['one'])

    self.assert_('one' not in self.ls._names())

  def testRemoveNonBlocking(self):

    self.assertRaises(NotImplementedError, self.ls.remove, 'one', blocking=0)

    self.ls.acquire('one')

    self.assertEquals(self.ls.remove('one', blocking=0), ['one'])

    self.ls.acquire(['two', 'three'])

    self.assertEquals(self.ls.remove(['two', 'three'], blocking=0),

                      ['two', 'three'])

  def testNoDoubleAdd(self):

    self.assertRaises(errors.LockError, self.ls.add, 'two')

    self.ls.add('four')

    self.assertRaises(errors.LockError, self.ls.add, 'four')

  def testNoWrongRemoves(self):

    self.ls.acquire(['one', 'three'], shared=1)

    # Cannot remove 'two' while holding something which is not a superset

    self.assertRaises(AssertionError, self.ls.remove, 'two')

    # Cannot remove 'three' as we are sharing it

    self.assertRaises(AssertionError, self.ls.remove, 'three')

  def testAcquireSetLock(self):

    # acquire the set-lock exclusively

    self.assertEquals(self.ls.acquire(None), set(['one', 'two', 'three']))

    self.assertEquals(self.ls._list_owned(), set(['one', 'two', 'three']))

    self.assertEquals(self.ls._is_owned(), True)

    self.assertEquals(self.ls._names(), set(['one', 'two', 'three']))

    # I can still add/remove elements...

    self.assertEquals(self.ls.remove(['two', 'three']), ['two', 'three'])

    self.assert_(self.ls.add('six'))

    self.ls.release()

    # share the set-lock

    self.assertEquals(self.ls.acquire(None, shared=1), set(['one', 'six']))

    # adding new elements is not possible

    self.assertRaises(AssertionError, self.ls.add, 'five')

    self.ls.release()

  def testAcquireWithRepetitions(self):

    self.assertEquals(self.ls.acquire(['two', 'two', 'three'], shared=1),

                      set(['two', 'two', 'three']))

    self.ls.release(['two', 'two'])

    self.assertEquals(self.ls._list_owned(), set(['three']))

  def testEmptyAcquire(self):

    # Acquire an empty list of locks...

    self.assertEquals(self.ls.acquire([]), set())

    self.assertEquals(self.ls._list_owned(), set())

    # New locks can still be addded

    self.assert_(self.ls.add('six'))

    # "re-acquiring" is not an issue, since we had really acquired nothing

    self.assertEquals(self.ls.acquire([], shared=1), set())

    self.assertEquals(self.ls._list_owned(), set())

    # We haven't really acquired anything, so we cannot release

    self.assertRaises(AssertionError, self.ls.release)

  def _doLockSet(self, names, shared):

    try:

      self.ls.acquire(names, shared=shared)

      self.done.put('DONE')

      self.ls.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doAddSet(self, names):

    try:

      self.ls.add(names, acquired=1)

      self.done.put('DONE')

      self.ls.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doRemoveSet(self, names):

    self.done.put(self.ls.remove(names))

  @_Repeat

  def testConcurrentSharedAcquire(self):

    self.ls.acquire(['one', 'two'], shared=1)

    self._addThread(target=self._doLockSet, args=(['one', 'two'], 1))

    self._waitThreads()

    self.assertEqual(self.done.get_nowait(), 'DONE')

    self._addThread(target=self._doLockSet, args=(['one', 'two', 'three'], 1))

    self._waitThreads()

    self.assertEqual(self.done.get_nowait(), 'DONE')

    self._addThread(target=self._doLockSet, args=('three', 1))

    self._waitThreads()

    self.assertEqual(self.done.get_nowait(), 'DONE')