Simplify public symbol exports

Inspired by tulip, have every module define a __all__ list and import *
from the top-level module.

Rename transport.set_defaults() since we don't want this to be a
top-level set_defaults() function as there may be multiple.

Also, rather than configuring flake8 to allow star imports, just exclude
the __init__.py files from flake8 checks.

oslo/messaging/__init__.py

@@ -13,43 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from oslo.messaging import exceptions
-from oslo.messaging.rpc import client
-from oslo.messaging.rpc import dispatcher as rpc_dispatcher
-from oslo.messaging.rpc import server as rpc_server
-from oslo.messaging import serializer
-from oslo.messaging import server
-from oslo.messaging import target
-from oslo.messaging import transport
-
-
-get_transport = transport.get_transport
-Target = target.Target
-
-RPCClient = client.RPCClient
-
-MessageHandlingServer = server.MessageHandlingServer
-get_rpc_server = rpc_server.get_rpc_server
-RPCDispatcher = rpc_dispatcher.RPCDispatcher
-Serializer = serializer.Serializer
-
-
-#
-# Exceptions
-#
-MessagingException = exceptions.MessagingException
-MessagingTimeout = exceptions.MessagingTimeout
-
-DriverLoadFailure = transport.DriverLoadFailure
-InvalidTransportURL = transport.InvalidTransportURL
-
-RPCVersionCapError = client.RPCVersionCapError
-ClientSendError = client.ClientSendError
-
-MessagingServerError = server.MessagingServerError
-ExecutorLoadFailure = server.ExecutorLoadFailure
-ServerListenError = server.ServerListenError
-
-RPCDispatcherError = rpc_dispatcher.RPCDispatcherError
-NoSuchMethod = rpc_dispatcher.NoSuchMethod
-UnsupportedVersion = rpc_dispatcher.UnsupportedVersion
+from .exceptions import *
+from .rpc import *
+from .serializer import *
+from .server import *
+from .target import *
+from .transport import *

oslo/messaging/exceptions.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = ['MessagingException', 'MessagingTimeout']
+
 
 class MessagingException(Exception):
     """Base class for exceptions."""

oslo/messaging/rpc/__init__.py

@@ -12,3 +12,18 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
+
+__all__ = [
+    'ClientSendError',
+    'NoSuchMethod',
+    'RPCClient',
+    'RPCDispatcher',
+    'RPCDispatcherError',
+    'RPCVersionCapError',
+    'UnsupportedVersion',
+    'get_rpc_server',
+]
+
+from client import *
+from dispatcher import *
+from server import *

oslo/messaging/rpc/client.py

@@ -16,6 +16,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = [
+    'ClientSendError',
+    'RPCClient',
+    'RPCVersionCapError',
+]
+
 import inspect
 import logging
 

oslo/messaging/rpc/dispatcher.py

@@ -16,6 +16,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = [
+    'NoSuchMethod',
+    'RPCDispatcher',
+    'RPCDispatcherError',
+    'UnsupportedVersion',
+]
+
 import logging
 
 from oslo.messaging import _utils as utils

oslo/messaging/rpc/server.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = ['get_rpc_server']
+
 from oslo.messaging.rpc import dispatcher as rpc_dispatcher
 from oslo.messaging import server as msg_server
 

oslo/messaging/serializer.py

@@ -12,6 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = ['Serializer', 'NoOpSerializer']
+
 """Provides the definition of a message serialization handler"""
 
 import abc

oslo/messaging/server.py

@@ -16,6 +16,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = [
+    'ExecutorLoadFailure',
+    'MessageHandlingServer',
+    'MessagingServerError',
+    'ServerListenError',
+]
+
 import logging
 
 from stevedore import driver

oslo/messaging/transport.py

@@ -16,6 +16,14 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+__all__ = [
+    'DriverLoadFailure',
+    'InvalidTransportURL',
+    'Transport',
+    'get_transport',
+    'set_transport_defaults',
+]
+
 import urlparse
 
 from oslo.config import cfg
@@ -42,7 +50,7 @@ _transport_opts = [
 ]
 
 
-def set_defaults(control_exchange):
+def set_transport_defaults(control_exchange):
     """Set defaults for messaging transport configuration options.
 
     :param control_exchange: the default exchange under which topics are scoped

tests/test_transport.py

@@ -209,12 +209,12 @@ class TestSetDefaults(test_utils.BaseTestCase):
 
     def setUp(self):
         super(TestSetDefaults, self).setUp(conf=cfg.ConfigOpts())
-        self.useFixture(_SetDefaultsFixture(transport.set_defaults,
+        self.useFixture(_SetDefaultsFixture(messaging.set_transport_defaults,
                                             transport._transport_opts,
                                             'control_exchange'))
 
     def test_set_default_control_exchange(self):
-        transport.set_defaults(control_exchange='foo')
+        messaging.set_transport_defaults(control_exchange='foo')
 
         self.mox.StubOutWithMock(driver, 'DriverManager')
         invoke_kwds = mox.ContainsKeyValue('default_exchange', 'foo')

tox.ini

@@ -20,5 +20,5 @@ commands = {posargs}
 
 [flake8]
 show-source = True
-exclude = .tox,dist,doc,*.egg,build
+exclude = .tox,dist,doc,*.egg,build,__init__.py
 builtins = _