Merge "Replace ThreadPoolExecutor with GreenThreadPoolExecutor"

lower-constraints.txt

@@ -32,8 +32,7 @@ fasteners==0.14.1
 fixtures==3.0.0
 flake8==2.5.5
 future==0.16.0
-futurist==1.6.0
-futures==3.0.0
+futurist==1.8.0
 gabbi==1.35.0
 gitdb2==2.0.3
 GitPython==2.1.8

nova/compute/manager.py

@@ -27,9 +27,6 @@ terminating it.
 
 import base64
 import binascii
-# If py2, concurrent.futures comes from the futures library otherwise it
-# comes from the py3 standard library.
-from concurrent import futures
 import contextlib
 import functools
 import inspect
@@ -43,6 +40,7 @@ import eventlet.event
 from eventlet import greenthread
 import eventlet.semaphore
 import eventlet.timeout
+import futurist
 from keystoneauth1 import exceptions as keystone_exception
 from oslo_log import log as logging
 import oslo_messaging as messaging
@@ -523,13 +521,10 @@ class ComputeManager(manager.Manager):
         else:
             self._build_semaphore = compute_utils.UnlimitedSemaphore()
         if max(CONF.max_concurrent_live_migrations, 0) != 0:
-            self._live_migration_executor = futures.ThreadPoolExecutor(
+            self._live_migration_executor = futurist.GreenThreadPoolExecutor(
                 max_workers=CONF.max_concurrent_live_migrations)
         else:
-            # Starting in python 3.5, this is technically bounded, but it's
-            # ncpu * 5 which is probably much higher than anyone would sanely
-            # use for concurrently running live migrations.
-            self._live_migration_executor = futures.ThreadPoolExecutor()
+            self._live_migration_executor = futurist.GreenThreadPoolExecutor()
         # This is a dict, keyed by instance uuid, to a two-item tuple of
         # migration object and Future for the queued live migration.
         self._waiting_live_migrations = {}
@@ -6357,8 +6352,9 @@ class ComputeManager(manager.Manager):
                 block_migration, migration, migrate_data)
             self._waiting_live_migrations[instance.uuid] = (migration, future)
         except RuntimeError:
-            # ThreadPoolExecutor.submit will raise RuntimeError if the pool
-            # is shutdown, which happens in _cleanup_live_migrations_in_pool.
+            # GreenThreadPoolExecutor.submit will raise RuntimeError if the
+            # pool is shutdown, which happens in
+            # _cleanup_live_migrations_in_pool.
             LOG.info('Migration %s failed to submit as the compute service '
                      'is shutting down.', migration.uuid, instance=instance)
             self._set_migration_status(migration, 'error')

nova/tests/fixtures.py

@@ -1065,7 +1065,7 @@ class SpawnIsSynchronousFixture(fixtures.Fixture):
 
 
 class SynchronousThreadPoolExecutorFixture(fixtures.Fixture):
-    """Make ThreadPoolExecutor.submit() synchronous.
+    """Make GreenThreadPoolExecutor.submit() synchronous.
 
     The function passed to submit() will be executed and a mock.Mock
     object will be returned as the Future where Future.result() will
@@ -1076,11 +1076,11 @@ class SynchronousThreadPoolExecutorFixture(fixtures.Fixture):
 
         def fake_submit(_self, fn, *args, **kwargs):
             result = fn(*args, **kwargs)
-            future = mock.Mock(spec='concurrent.futures.Future')
+            future = mock.Mock(spec='futurist.Future')
             future.return_value.result.return_value = result
             return future
         self.useFixture(fixtures.MonkeyPatch(
-            'concurrent.futures.ThreadPoolExecutor.submit',
+            'futurist.GreenThreadPoolExecutor.submit',
             fake_submit))
 
 

nova/tests/functional/api_sample_tests/test_server_migrations.py

@@ -13,9 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from concurrent import futures
 import datetime
 
+import futurist
 import mock
 
 from nova.conductor import manager as conductor_manager
@@ -241,7 +241,7 @@ class ServerMigrationsSampleJsonTestV2_65(ServerMigrationsSampleJsonTestV2_24):
         self._do_post('servers/%s/action' % self.uuid, 'live-migrate-server',
                       {'hostname': self.compute.host})
         self.compute._waiting_live_migrations[self.uuid] = (
-            self.migration, futures.Future())
+            self.migration, futurist.Future())
         uri = 'servers/%s/migrations/%s' % (self.uuid, self.migration.id)
         response = self._do_delete(uri)
         self.assertEqual(202, response.status_code)

nova/tests/unit/compute/test_compute_mgr.py

@@ -7214,7 +7214,7 @@ class ComputeManagerMigrationTestCase(test.NoDBTestCase):
         self.flags(max_concurrent_live_migrations=0)
         self._test_max_concurrent_live()
 
-    @mock.patch('concurrent.futures.ThreadPoolExecutor')
+    @mock.patch('futurist.GreenThreadPoolExecutor')
     def test_max_concurrent_live_semaphore_limited(self, mock_executor):
         self.flags(max_concurrent_live_migrations=123)
         manager.ComputeManager()
@@ -7224,7 +7224,7 @@ class ComputeManagerMigrationTestCase(test.NoDBTestCase):
     def test_max_concurrent_live_semaphore_unlimited(self, max_concurrent):
         self.flags(max_concurrent_live_migrations=max_concurrent)
         with mock.patch(
-                'concurrent.futures.ThreadPoolExecutor') as mock_executor:
+                'futurist.GreenThreadPoolExecutor') as mock_executor:
             manager.ComputeManager()
         mock_executor.assert_called_once_with()
 

requirements.txt

@@ -69,4 +69,4 @@ os-service-types>=1.2.0 # Apache-2.0
 taskflow>=2.16.0 # Apache-2.0
 python-dateutil>=2.5.3 # BSD
 zVMCloudConnector>=1.1.1;sys_platform!='win32'  # Apache 2.0 License
-futures>=3.0.0;python_version=='2.7' or python_version=='2.6' # PSF
+futurist>=1.8.0 # Apache-2.0