From 77da93886be61230dea5a4a4c4de036a57e62550 Mon Sep 17 00:00:00 2001 From: Vishvananda Ishaya Date: Wed, 9 Mar 2011 06:56:42 +0000 Subject: tests and semaphore fix for image caching --- nova/tests/test_virt.py | 66 +++++++++++++++++++++++++++++++++++++++++++++++ nova/virt/libvirt_conn.py | 14 +++++++--- 2 files changed, 76 insertions(+), 4 deletions(-) diff --git a/nova/tests/test_virt.py b/nova/tests/test_virt.py index f151ae911..ec7498d72 100644 --- a/nova/tests/test_virt.py +++ b/nova/tests/test_virt.py @@ -14,12 +14,16 @@ # License for the specific language governing permissions and limitations # under the License. +import os + +import eventlet from xml.etree.ElementTree import fromstring as xml_to_tree from xml.dom.minidom import parseString as xml_to_dom from nova import context from nova import db from nova import flags +from nova import log as logging from nova import test from nova import utils from nova.api.ec2 import cloud @@ -30,6 +34,68 @@ FLAGS = flags.FLAGS flags.DECLARE('instances_path', 'nova.compute.manager') +def _concurrency(wait, done, target): + wait.wait() + done.send() + + +class CacheConcurrencyTestCase(test.TestCase): + def setUp(self): + super(CacheConcurrencyTestCase, self).setUp() + + def fake_exists(fname): + basedir = os.path.join(FLAGS.instances_path, '_base') + if fname == basedir: + return True + return False + + def fake_execute(*args, **kwargs): + pass + + self.stubs.Set(os.path, 'exists', fake_exists) + self.stubs.Set(utils, 'execute', fake_execute) + + def test_same_fname_concurrency(self): + """Ensures that the same fname cache runs at a sequentially""" + conn = libvirt_conn.get_connection(False) + wait1 = eventlet.event.Event() + done1 = eventlet.event.Event() + eventlet.spawn(conn._cache_image, _concurrency, + 'target', 'fname', False, wait1, done1) + wait2 = eventlet.event.Event() + done2 = eventlet.event.Event() + eventlet.spawn(conn._cache_image, _concurrency, + 'target', 'fname', False, wait2, done2) + wait2.send() + eventlet.sleep(0) + try: + self.assertFalse(done2.ready()) + finally: + wait1.send() + done1.wait() + eventlet.sleep(0) + self.assertTrue(done2.ready()) + + def test_different_fname_concurrency(self): + """Ensures that two different fname caches are concurrent""" + conn = libvirt_conn.get_connection(False) + wait1 = eventlet.event.Event() + done1 = eventlet.event.Event() + eventlet.spawn(conn._cache_image, _concurrency, + 'target', 'fname2', False, wait1, done1) + wait2 = eventlet.event.Event() + done2 = eventlet.event.Event() + eventlet.spawn(conn._cache_image, _concurrency, + 'target', 'fname1', False, wait2, done2) + wait2.send() + eventlet.sleep(0) + try: + self.assertTrue(done2.ready()) + finally: + wait1.send() + eventlet.sleep(0) + + class LibvirtConnTestCase(test.TestCase): def setUp(self): super(LibvirtConnTestCase, self).setUp() diff --git a/nova/virt/libvirt_conn.py b/nova/virt/libvirt_conn.py index 9f7315c17..1a1f146d4 100644 --- a/nova/virt/libvirt_conn.py +++ b/nova/virt/libvirt_conn.py @@ -44,9 +44,8 @@ import uuid from xml.dom import minidom -from eventlet import greenthread -from eventlet import event from eventlet import tpool +from eventlet import semaphore import IPy @@ -512,6 +511,8 @@ class LibvirtConnection(object): subprocess.Popen(cmd, shell=True) return {'token': token, 'host': host, 'port': port} + _image_semaphores = {} + def _cache_image(self, fn, target, fname, cow=False, *args, **kwargs): """Wrapper for a method that creates an image that caches the image. @@ -531,8 +532,13 @@ class LibvirtConnection(object): if not os.path.exists(base_dir): os.mkdir(base_dir) base = os.path.join(base_dir, fname) - if not os.path.exists(base): - fn(target=base, *args, **kwargs) + + if fname not in self._image_semaphores: + self._image_semaphores[fname] = semaphore.Semaphore() + with self._image_semaphores[fname]: + if not os.path.exists(base): + fn(target=base, *args, **kwargs) + if cow: utils.execute('qemu-img create -f qcow2 -o ' 'cluster_size=2M,backing_file=%s %s' -- cgit From ddeab2da30bb2f74109854d982c6681e78e7a4ce Mon Sep 17 00:00:00 2001 From: Vishvananda Ishaya Date: Wed, 9 Mar 2011 07:35:58 +0000 Subject: make static method for testing without initializing libvirt --- nova/tests/test_virt.py | 4 ++-- nova/virt/libvirt_conn.py | 11 ++++++----- 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/nova/tests/test_virt.py b/nova/tests/test_virt.py index ec7498d72..113632a0c 100644 --- a/nova/tests/test_virt.py +++ b/nova/tests/test_virt.py @@ -57,7 +57,7 @@ class CacheConcurrencyTestCase(test.TestCase): def test_same_fname_concurrency(self): """Ensures that the same fname cache runs at a sequentially""" - conn = libvirt_conn.get_connection(False) + conn = libvirt_conn.LibvirtConnection wait1 = eventlet.event.Event() done1 = eventlet.event.Event() eventlet.spawn(conn._cache_image, _concurrency, @@ -78,7 +78,7 @@ class CacheConcurrencyTestCase(test.TestCase): def test_different_fname_concurrency(self): """Ensures that two different fname caches are concurrent""" - conn = libvirt_conn.get_connection(False) + conn = libvirt_conn.LibvirtConnection wait1 = eventlet.event.Event() done1 = eventlet.event.Event() eventlet.spawn(conn._cache_image, _concurrency, diff --git a/nova/virt/libvirt_conn.py b/nova/virt/libvirt_conn.py index 1a1f146d4..ecef7950a 100644 --- a/nova/virt/libvirt_conn.py +++ b/nova/virt/libvirt_conn.py @@ -511,9 +511,10 @@ class LibvirtConnection(object): subprocess.Popen(cmd, shell=True) return {'token': token, 'host': host, 'port': port} - _image_semaphores = {} + _image_sems = {} - def _cache_image(self, fn, target, fname, cow=False, *args, **kwargs): + @staticmethod + def _cache_image(fn, target, fname, cow=False, *args, **kwargs): """Wrapper for a method that creates an image that caches the image. This wrapper will save the image into a common store and create a @@ -533,9 +534,9 @@ class LibvirtConnection(object): os.mkdir(base_dir) base = os.path.join(base_dir, fname) - if fname not in self._image_semaphores: - self._image_semaphores[fname] = semaphore.Semaphore() - with self._image_semaphores[fname]: + if fname not in LibvirtConnection._image_sems: + LibvirtConnection._image_sems[fname] = semaphore.Semaphore() + with LibvirtConnection._image_sems[fname]: if not os.path.exists(base): fn(target=base, *args, **kwargs) -- cgit From 3e61bf9963d7e98e8152d2eacfc4461d8cda309c Mon Sep 17 00:00:00 2001 From: Vishvananda Ishaya Date: Wed, 9 Mar 2011 21:43:35 +0000 Subject: remove the semaphore when there is no one waiting on it --- nova/tests/test_virt.py | 3 ++- nova/virt/libvirt_conn.py | 2 ++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/nova/tests/test_virt.py b/nova/tests/test_virt.py index 113632a0c..56a271365 100644 --- a/nova/tests/test_virt.py +++ b/nova/tests/test_virt.py @@ -23,7 +23,6 @@ from xml.dom.minidom import parseString as xml_to_dom from nova import context from nova import db from nova import flags -from nova import log as logging from nova import test from nova import utils from nova.api.ec2 import cloud @@ -70,11 +69,13 @@ class CacheConcurrencyTestCase(test.TestCase): eventlet.sleep(0) try: self.assertFalse(done2.ready()) + self.assertTrue('fname' in conn._image_sems) finally: wait1.send() done1.wait() eventlet.sleep(0) self.assertTrue(done2.ready()) + self.assertFalse('fname' in conn._image_sems) def test_different_fname_concurrency(self): """Ensures that two different fname caches are concurrent""" diff --git a/nova/virt/libvirt_conn.py b/nova/virt/libvirt_conn.py index ecef7950a..69249ed57 100644 --- a/nova/virt/libvirt_conn.py +++ b/nova/virt/libvirt_conn.py @@ -539,6 +539,8 @@ class LibvirtConnection(object): with LibvirtConnection._image_sems[fname]: if not os.path.exists(base): fn(target=base, *args, **kwargs) + if not LibvirtConnection._image_sems[fname].locked(): + del LibvirtConnection._image_sems[fname] if cow: utils.execute('qemu-img create -f qcow2 -o ' -- cgit