Merge "[zmq] Support message versions for rolling upgrades"5.14.0

15 files changed, 432 insertions, 126 deletions

diff --git a/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py b/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
index 5de32bb..09bec6f 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
@@ -35,7 +35,7 @@ class PublisherBase(object):
 
     def __init__(self, sockets_manager, sender, receiver):
 
-        """Construct publisher
+        """Construct publisher.
 
         Accept sockets manager, sender and receiver objects.
 
@@ -54,7 +54,7 @@ class PublisherBase(object):
 
     @abc.abstractmethod
     def acquire_connection(self, request):
-        """Get socket to publish request on it
+        """Get socket to publish request on it.
 
         :param request: request object
         :type senders: zmq_request.Request
@@ -62,7 +62,7 @@ class PublisherBase(object):
 
     @abc.abstractmethod
     def send_request(self, socket, request):
-        """Publish request on a socket
+        """Publish request on a socket.
 
         :param socket: socket object to publish request on
         :type socket: zmq_socket.ZmqSocket
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
index 5bdfb0f..7754c24 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
@@ -22,6 +22,7 @@ import six
 from oslo_messaging._drivers.zmq_driver.client import zmq_response
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging._i18n import _LE
 
 LOG = logging.getLogger(__name__)
@@ -52,6 +53,8 @@ class ReceiverBase(object):
         self._lock = threading.Lock()
         self._requests = {}
         self._poller = zmq_async.get_poller()
+        self._receive_response_versions = \
+            zmq_version.get_method_versions(self, 'receive_response')
         self._executor = zmq_async.get_executor(self._run_loop)
         self._executor.execute()
 
@@ -121,6 +124,12 @@ class ReceiverBase(object):
                       {"msg_type": zmq_names.message_type_str(message_type),
                        "msg_id": message_id})
 
+    def _get_receive_response_version(self, version):
+        receive_response_version = self._receive_response_versions.get(version)
+        if receive_response_version is None:
+            raise zmq_version.UnsupportedMessageVersionError(version)
+        return receive_response_version
+
 
 class ReceiverProxy(ReceiverBase):
 
@@ -128,6 +137,14 @@ class ReceiverProxy(ReceiverBase):
     def receive_response(self, socket):
         empty = socket.recv()
         assert empty == b'', "Empty delimiter expected!"
+        message_version = socket.recv_string()
+        assert message_version != b'', "Valid message version expected!"
+
+        receive_response_version = \
+            self._get_receive_response_version(message_version)
+        return receive_response_version(socket)
+
+    def _receive_response_v_1_0(self, socket):
         reply_id = socket.recv()
         assert reply_id != b'', "Valid reply id expected!"
         message_type = int(socket.recv())
@@ -153,6 +170,14 @@ class ReceiverDirect(ReceiverBase):
     def receive_response(self, socket):
         empty = socket.recv()
         assert empty == b'', "Empty delimiter expected!"
+        message_version = socket.recv_string()
+        assert message_version != b'', "Valid message version expected!"
+
+        receive_response_version = \
+            self._get_receive_response_version(message_version)
+        return receive_response_version(socket)
+
+    def _receive_response_v_1_0(self, socket):
         message_type = int(socket.recv())
         assert message_type in zmq_names.RESPONSE_TYPES, "Response expected!"
         message_id = socket.recv_string()
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_request.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_request.py
index 5d1a044..d2b3110 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_request.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_request.py
@@ -1,4 +1,4 @@
-#    Copyright 2015 Mirantis, Inc.
+#    Copyright 2015-2016 Mirantis, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -20,6 +20,7 @@ import six
 
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging._i18n import _LE
 
 LOG = logging.getLogger(__name__)
@@ -73,6 +74,10 @@ class Request(object):
     def msg_type(self):
         """ZMQ request type"""
 
+    @property
+    def message_version(self):
+        return zmq_version.MESSAGE_VERSION
+
 
 class RpcRequest(Request):
 
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
index 3da30b6..140feed 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
@@ -22,12 +22,13 @@ from oslo_messaging._drivers.zmq_driver import zmq_names
 @six.add_metaclass(abc.ABCMeta)
 class Response(object):
 
-    def __init__(self, message_id=None, reply_id=None):
+    def __init__(self, message_id=None, reply_id=None, message_version=None):
         if self.msg_type not in zmq_names.RESPONSE_TYPES:
             raise RuntimeError("Unknown response type!")
 
         self._message_id = message_id
         self._reply_id = reply_id
+        self._message_version = message_version
 
     @abc.abstractproperty
     def msg_type(self):
@@ -41,9 +42,14 @@ class Response(object):
     def reply_id(self):
         return self._reply_id
 
+    @property
+    def message_version(self):
+        return self._message_version
+
     def to_dict(self):
         return {zmq_names.FIELD_MSG_ID: self._message_id,
-                zmq_names.FIELD_REPLY_ID: self._reply_id}
+                zmq_names.FIELD_REPLY_ID: self._reply_id,
+                zmq_names.FIELD_MSG_VERSION: self._message_version}
 
     def __str__(self):
         return str(self.to_dict())
@@ -58,9 +64,9 @@ class Reply(Response):
 
     msg_type = zmq_names.REPLY_TYPE
 
-    def __init__(self, message_id=None, reply_id=None, reply_body=None,
-                 failure=None):
-        super(Reply, self).__init__(message_id, reply_id)
+    def __init__(self, message_id=None, reply_id=None, message_version=None,
+                 reply_body=None, failure=None):
+        super(Reply, self).__init__(message_id, reply_id, message_version)
         self._reply_body = reply_body
         self._failure = failure
 
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
index 909c868..f63e1d7 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
@@ -20,6 +20,7 @@ import six
 
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
 
 LOG = logging.getLogger(__name__)
 
@@ -28,11 +29,18 @@ zmq = zmq_async.import_zmq()
 
 @six.add_metaclass(abc.ABCMeta)
 class SenderBase(object):
-    """Base request/ack/reply sending interface."""
+    """Base request/response sending interface."""
 
     def __init__(self, conf):
         self.conf = conf
         self._lock = threading.Lock()
+        self._send_versions = zmq_version.get_method_versions(self, 'send')
+
+    def _get_send_version(self, version):
+        send_version = self._send_versions.get(version)
+        if send_version is None:
+            raise zmq_version.UnsupportedMessageVersionError(version)
+        return send_version
 
     @abc.abstractmethod
     def send(self, socket, message):
@@ -54,18 +62,24 @@ class ReplySenderBase(SenderBase):
 class RequestSenderProxy(RequestSenderBase):
 
     def send(self, socket, request):
+        assert request.msg_type in zmq_names.REQUEST_TYPES, "Request expected!"
+
+        send_version = self._get_send_version(request.message_version)
+
         with self._lock:
-            self._send(socket, request)
+            send_version(socket, request)
 
         LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s message "
-                  "%(msg_id)s to target %(target)s",
+                  "%(msg_id)s to target %(target)s (v%(msg_version)s)",
                   {"addr": list(socket.connections),
                    "msg_type": zmq_names.message_type_str(request.msg_type),
                    "msg_id": request.message_id,
-                   "target": request.target})
+                   "target": request.target,
+                   "msg_version": request.message_version})
 
-    def _send(self, socket, request):
+    def _send_v_1_0(self, socket, request):
         socket.send(b'', zmq.SNDMORE)
+        socket.send_string('1.0', zmq.SNDMORE)
         socket.send(six.b(str(request.msg_type)), zmq.SNDMORE)
         socket.send(request.routing_key, zmq.SNDMORE)
         socket.send_string(request.message_id, zmq.SNDMORE)
@@ -77,16 +91,21 @@ class AckSenderProxy(AckSenderBase):
     def send(self, socket, ack):
         assert ack.msg_type == zmq_names.ACK_TYPE, "Ack expected!"
 
+        send_version = self._get_send_version(ack.message_version)
+
         with self._lock:
-            self._send(socket, ack)
+            send_version(socket, ack)
 
-        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s",
+        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s "
+                  "(v%(msg_version)s)",
                   {"addr": list(socket.connections),
                    "msg_type": zmq_names.message_type_str(ack.msg_type),
-                   "msg_id": ack.message_id})
+                   "msg_id": ack.message_id,
+                   "msg_version": ack.message_version})
 
-    def _send(self, socket, ack):
+    def _send_v_1_0(self, socket, ack):
         socket.send(b'', zmq.SNDMORE)
+        socket.send_string('1.0', zmq.SNDMORE)
         socket.send(six.b(str(ack.msg_type)), zmq.SNDMORE)
         socket.send(ack.reply_id, zmq.SNDMORE)
         socket.send_string(ack.message_id)
@@ -97,16 +116,21 @@ class ReplySenderProxy(ReplySenderBase):
     def send(self, socket, reply):
         assert reply.msg_type == zmq_names.REPLY_TYPE, "Reply expected!"
 
+        send_version = self._get_send_version(reply.message_version)
+
         with self._lock:
-            self._send(socket, reply)
+            send_version(socket, reply)
 
-        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s",
+        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s "
+                  "(v%(msg_version)s)",
                   {"addr": list(socket.connections),
                    "msg_type": zmq_names.message_type_str(reply.msg_type),
-                   "msg_id": reply.message_id})
+                   "msg_id": reply.message_id,
+                   "msg_version": reply.message_version})
 
-    def _send(self, socket, reply):
+    def _send_v_1_0(self, socket, reply):
         socket.send(b'', zmq.SNDMORE)
+        socket.send_string('1.0', zmq.SNDMORE)
         socket.send(six.b(str(reply.msg_type)), zmq.SNDMORE)
         socket.send(reply.reply_id, zmq.SNDMORE)
         socket.send_string(reply.message_id, zmq.SNDMORE)
@@ -116,17 +140,23 @@ class ReplySenderProxy(ReplySenderBase):
 class RequestSenderDirect(RequestSenderBase):
 
     def send(self, socket, request):
+        assert request.msg_type in zmq_names.REQUEST_TYPES, "Request expected!"
+
+        send_version = self._get_send_version(request.message_version)
+
         with self._lock:
-            self._send(socket, request)
+            send_version(socket, request)
 
         LOG.debug("Sending %(msg_type)s message %(msg_id)s to "
-                  "target %(target)s",
+                  "target %(target)s (v%(msg_version)s)",
                   {"msg_type": zmq_names.message_type_str(request.msg_type),
                    "msg_id": request.message_id,
-                   "target": request.target})
+                   "target": request.target,
+                   "msg_version": request.message_version})
 
-    def _send(self, socket, request):
+    def _send_v_1_0(self, socket, request):
         socket.send(b'', zmq.SNDMORE)
+        socket.send_string('1.0', zmq.SNDMORE)
         socket.send(six.b(str(request.msg_type)), zmq.SNDMORE)
         socket.send_string(request.message_id, zmq.SNDMORE)
         socket.send_dumped([request.context, request.message])
@@ -137,14 +167,17 @@ class AckSenderDirect(AckSenderBase):
     def send(self, socket, ack):
         assert ack.msg_type == zmq_names.ACK_TYPE, "Ack expected!"
 
+        send_version = self._get_send_version(ack.message_version)
+
         with self._lock:
-            self._send(socket, ack)
+            send_version(socket, ack)
 
-        LOG.debug("Sending %(msg_type)s for %(msg_id)s",
+        LOG.debug("Sending %(msg_type)s for %(msg_id)s (v%(msg_version)s)",
                   {"msg_type": zmq_names.message_type_str(ack.msg_type),
-                   "msg_id": ack.message_id})
+                   "msg_id": ack.message_id,
+                   "msg_version": ack.message_version})
 
-    def _send(self, socket, ack):
+    def _send_v_1_0(self, socket, ack):
         raise NotImplementedError()
 
 
@@ -153,16 +186,20 @@ class ReplySenderDirect(ReplySenderBase):
     def send(self, socket, reply):
         assert reply.msg_type == zmq_names.REPLY_TYPE, "Reply expected!"
 
+        send_version = self._get_send_version(reply.message_version)
+
         with self._lock:
-            self._send(socket, reply)
+            send_version(socket, reply)
 
-        LOG.debug("Sending %(msg_type)s for %(msg_id)s",
+        LOG.debug("Sending %(msg_type)s for %(msg_id)s (v%(msg_version)s)",
                   {"msg_type": zmq_names.message_type_str(reply.msg_type),
-                   "msg_id": reply.message_id})
+                   "msg_id": reply.message_id,
+                   "msg_version": reply.message_version})
 
-    def _send(self, socket, reply):
+    def _send_v_1_0(self, socket, reply):
         socket.send(reply.reply_id, zmq.SNDMORE)
         socket.send(b'', zmq.SNDMORE)
+        socket.send_string('1.0', zmq.SNDMORE)
         socket.send(six.b(str(reply.msg_type)), zmq.SNDMORE)
         socket.send_string(reply.message_id, zmq.SNDMORE)
         socket.send_dumped([reply.reply_body, reply.failure])
diff --git a/oslo_messaging/_drivers/zmq_driver/proxy/zmq_base_proxy.py b/oslo_messaging/_drivers/zmq_driver/proxy/zmq_base_proxy.py
index 4bfe521..a1600b5 100644
--- a/oslo_messaging/_drivers/zmq_driver/proxy/zmq_base_proxy.py
+++ b/oslo_messaging/_drivers/zmq_driver/proxy/zmq_base_proxy.py
@@ -28,12 +28,16 @@ zmq = zmq_async.import_zmq()
 
 
 def check_message_format(func):
-    def _check_message_format(*args, **kwargs):
+    def _check_message_format(socket):
         try:
-            return func(*args, **kwargs)
+            return func(socket)
         except Exception as e:
-            LOG.error(_LE("Received message with wrong format"))
-            LOG.exception(e)
+            LOG.error(_LE("Received message with wrong format: %r. "
+                          "Dropping invalid message"), e)
+            # NOTE(gdavoian): drop the left parts of a broken message, since
+            # they most likely will break the order of next messages' parts
+            if socket.getsockopt(zmq.RCVMORE):
+                socket.recv_multipart()
     return _check_message_format
 
 
@@ -65,11 +69,12 @@ class ProxyBase(object):
     @check_message_format
     def _receive_message(socket):
         message = socket.recv_multipart()
-        assert len(message) > zmq_names.MESSAGE_ID_IDX, "Not enough parts"
-        assert message[zmq_names.REPLY_ID_IDX] != b'', "Valid id expected"
+        assert message[zmq_names.EMPTY_IDX] == b'', "Empty delimiter expected!"
         message_type = int(message[zmq_names.MESSAGE_TYPE_IDX])
-        assert message_type in zmq_names.MESSAGE_TYPES, "Known type expected!"
-        assert message[zmq_names.EMPTY_IDX] == b'', "Empty delimiter expected"
+        assert message_type in zmq_names.MESSAGE_TYPES, \
+            "Known message type expected!"
+        assert len(message) > zmq_names.MESSAGE_ID_IDX, \
+            "At least %d parts expected!" % (zmq_names.MESSAGE_ID_IDX + 1)
         return message
 
     def cleanup(self):
diff --git a/oslo_messaging/_drivers/zmq_driver/proxy/zmq_sender.py b/oslo_messaging/_drivers/zmq_driver/proxy/zmq_sender.py
index 8318d3b..0d1952a 100644
--- a/oslo_messaging/_drivers/zmq_driver/proxy/zmq_sender.py
+++ b/oslo_messaging/_drivers/zmq_driver/proxy/zmq_sender.py
@@ -19,6 +19,8 @@ import six
 
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
+from oslo_messaging._i18n import _LW
 
 LOG = logging.getLogger(__name__)
 
@@ -30,79 +32,116 @@ class Sender(object):
 
     @abc.abstractmethod
     def send_message(self, socket, multipart_message):
-        """Send message to a socket from multipart list"""
+        """Send message to a socket from a multipart list."""
 
 
-class CentralRouterSender(Sender):
+class CentralSender(Sender):
+
+    def __init__(self):
+        self._send_message_versions = \
+            zmq_version.get_method_versions(self, 'send_message')
 
     def send_message(self, socket, multipart_message):
+        message_version = multipart_message[zmq_names.MESSAGE_VERSION_IDX]
+        if six.PY3:
+            message_version = message_version.decode('utf-8')
+
+        send_message_version = self._send_message_versions.get(message_version)
+        if send_message_version is None:
+            LOG.warning(_LW("Dropping message with unsupported version %s"),
+                        message_version)
+            return
+
+        send_message_version(socket, multipart_message)
+
+
+class LocalSender(Sender):
+    pass
+
+
+class CentralRouterSender(CentralSender):
+
+    def _send_message_v_1_0(self, socket, multipart_message):
         message_type = int(multipart_message[zmq_names.MESSAGE_TYPE_IDX])
         routing_key = multipart_message[zmq_names.ROUTING_KEY_IDX]
         reply_id = multipart_message[zmq_names.REPLY_ID_IDX]
         message_id = multipart_message[zmq_names.MESSAGE_ID_IDX]
+        message_version = multipart_message[zmq_names.MESSAGE_VERSION_IDX]
 
         socket.send(routing_key, zmq.SNDMORE)
         socket.send(b'', zmq.SNDMORE)
+        socket.send(message_version, zmq.SNDMORE)
         socket.send(reply_id, zmq.SNDMORE)
         socket.send(multipart_message[zmq_names.MESSAGE_TYPE_IDX], zmq.SNDMORE)
         socket.send_multipart(multipart_message[zmq_names.MESSAGE_ID_IDX:])
 
         LOG.debug("Dispatching %(msg_type)s message %(msg_id)s - from %(rid)s "
-                  "-> to %(rkey)s",
+                  "-> to %(rkey)s (v%(msg_version)s)",
                   {"msg_type": zmq_names.message_type_str(message_type),
                    "msg_id": message_id,
                    "rkey": routing_key,
-                   "rid": reply_id})
+                   "rid": reply_id,
+                   "msg_version": message_version})
 
 
-class CentralAckSender(Sender):
+class CentralAckSender(CentralSender):
 
-    def send_message(self, socket, multipart_message):
+    def _send_message_v_1_0(self, socket, multipart_message):
         message_type = zmq_names.ACK_TYPE
         message_id = multipart_message[zmq_names.MESSAGE_ID_IDX]
         routing_key = socket.handle.identity
         reply_id = multipart_message[zmq_names.REPLY_ID_IDX]
+        message_version = multipart_message[zmq_names.MESSAGE_VERSION_IDX]
 
         socket.send(reply_id, zmq.SNDMORE)
         socket.send(b'', zmq.SNDMORE)
+        socket.send(message_version, zmq.SNDMORE)
         socket.send(routing_key, zmq.SNDMORE)
         socket.send(six.b(str(message_type)), zmq.SNDMORE)
         socket.send_string(message_id)
 
         LOG.debug("Sending %(msg_type)s for %(msg_id)s to %(rid)s "
-                  "[from %(rkey)s]",
+                  "[from %(rkey)s] (v%(msg_version)s)",
                   {"msg_type": zmq_names.message_type_str(message_type),
                    "msg_id": message_id,
                    "rid": reply_id,
-                   "rkey": routing_key})
+                   "rkey": routing_key,
+                   "msg_version": message_version})
 
 
-class CentralPublisherSender(Sender):
+class CentralPublisherSender(CentralSender):
 
-    def send_message(self, socket, multipart_message):
+    def _send_message_v_1_0(self, socket, multipart_message):
         message_type = int(multipart_message[zmq_names.MESSAGE_TYPE_IDX])
         assert message_type in zmq_names.MULTISEND_TYPES, "Fanout expected!"
         topic_filter = multipart_message[zmq_names.ROUTING_KEY_IDX]
         message_id = multipart_message[zmq_names.MESSAGE_ID_IDX]
+        message_version = multipart_message[zmq_names.MESSAGE_VERSION_IDX]
 
         socket.send(topic_filter, zmq.SNDMORE)
+        socket.send(message_version, zmq.SNDMORE)
         socket.send(six.b(str(message_type)), zmq.SNDMORE)
         socket.send_multipart(multipart_message[zmq_names.MESSAGE_ID_IDX:])
 
-        LOG.debug("Publishing message %(message_id)s on [%(topic)s]",
+        LOG.debug("Publishing message %(msg_id)s on [%(topic)s] "
+                  "(v%(msg_version)s)",
                   {"topic": topic_filter,
-                   "message_id": message_id})
+                   "msg_id": message_id,
+                   "msg_version": message_version})
 
 
-class LocalPublisherSender(Sender):
+class LocalPublisherSender(LocalSender):
 
     TOPIC_IDX = 0
-    MSG_TYPE_IDX = 1
-    MSG_ID_IDX = 2
+    MSG_VERSION_IDX = 1
+    MSG_TYPE_IDX = 2
+    MSG_ID_IDX = 3
 
     def send_message(self, socket, multipart_message):
         socket.send_multipart(multipart_message)
 
-        LOG.debug("Publishing message %(message_id)s on [%(topic)s]",
+        LOG.debug("Publishing message %(msg_id)s on [%(topic)s] "
+                  "(v%(msg_version)s)",
                   {"topic": multipart_message[self.TOPIC_IDX],
-                   "message_id": multipart_message[self.MSG_ID_IDX]})
+                   "msg_id": multipart_message[self.MSG_ID_IDX],
+                   "msg_version": multipart_message[self.MSG_VERSION_IDX]})
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_consumer_base.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_consumer_base.py
index 0b9fe62..b2e69fc 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_consumer_base.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_consumer_base.py
@@ -42,11 +42,11 @@ class ConsumerBase(object):
         self.context = zmq.Context()
 
     def stop(self):
-        """Stop consumer polling/updates"""
+        """Stop consumer polling/updating."""
 
     @abc.abstractmethod
-    def receive_message(self, target):
-        """Method for poller - receiving message routine"""
+    def receive_request(self, socket):
+        """Receive a request via a socket."""
 
     def cleanup(self):
         for socket in self.sockets:
@@ -81,7 +81,7 @@ class SingleSocketConsumer(ConsumerBase):
                        "port": socket.port})
             self.host = zmq_address.combine_address(
                 self.conf.oslo_messaging_zmq.rpc_zmq_host, socket.port)
-            self.poller.register(socket, self.receive_message)
+            self.poller.register(socket, self.receive_request)
             return socket
         except zmq.ZMQError as e:
             errmsg = _LE("Failed binding to port %(port)d: %(e)s")\
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
index 57c51ca..52fea53 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
@@ -29,6 +29,7 @@ from oslo_messaging._drivers.zmq_driver import zmq_address
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
 from oslo_messaging._drivers.zmq_driver import zmq_updater
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging._i18n import _LE, _LI, _LW
 
 LOG = logging.getLogger(__name__)
@@ -44,6 +45,8 @@ class DealerConsumer(zmq_consumer_base.SingleSocketConsumer):
             conf, server.matchmaker, zmq.DEALER)
         self.host = None
         super(DealerConsumer, self).__init__(conf, poller, server, zmq.DEALER)
+        self._receive_request_versions = \
+            zmq_version.get_method_versions(self, 'receive_request')
         self.connection_updater = ConsumerConnectionUpdater(
             conf, self.matchmaker, self.socket)
         LOG.info(_LI("[%s] Run DEALER consumer"), self.host)
@@ -59,7 +62,7 @@ class DealerConsumer(zmq_consumer_base.SingleSocketConsumer):
                 self._generate_identity())
             self.sockets.append(socket)
             self.host = socket.handle.identity
-            self.poller.register(socket, self.receive_message)
+            self.poller.register(socket, self.receive_request)
             return socket
         except zmq.ZMQError as e:
             LOG.error(_LE("Failed connecting to ROUTER socket %(e)s") % e)
@@ -70,48 +73,66 @@ class DealerConsumer(zmq_consumer_base.SingleSocketConsumer):
             failure = rpc_common.serialize_remote_exception(failure)
         reply = zmq_response.Reply(message_id=rpc_message.message_id,
                                    reply_id=rpc_message.reply_id,
+                                   message_version=rpc_message.message_version,
                                    reply_body=reply,
                                    failure=failure)
         self.reply_sender.send(rpc_message.socket, reply)
         return reply
 
-    def _create_message(self, context, message, reply_id, message_id, socket,
-                        message_type):
+    def _create_message(self, context, message, message_version, reply_id,
+                        message_id, socket, message_type):
         if message_type == zmq_names.CALL_TYPE:
             message = zmq_incoming_message.ZmqIncomingMessage(
-                context, message, reply_id=reply_id, message_id=message_id,
+                context, message, message_version=message_version,
+                reply_id=reply_id, message_id=message_id,
                 socket=socket, reply_method=self._reply
             )
         else:
             message = zmq_incoming_message.ZmqIncomingMessage(context, message)
 
-        LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s",
+        LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s "
+                  "(v%(msg_version)s)",
                   {"host": self.host,
                    "msg_type": zmq_names.message_type_str(message_type),
-                   "msg_id": message_id})
+                   "msg_id": message_id,
+                   "msg_version": message_version})
         return message
 
-    def receive_message(self, socket):
+    def _get_receive_request_version(self, version):
+        receive_request_version = self._receive_request_versions.get(version)
+        if receive_request_version is None:
+            raise zmq_version.UnsupportedMessageVersionError(version)
+        return receive_request_version
+
+    def receive_request(self, socket):
         try:
             empty = socket.recv()
             assert empty == b'', "Empty delimiter expected!"
-            reply_id = socket.recv()
-            assert reply_id != b'', "Valid reply id expected!"
-            message_type = int(socket.recv())
-            assert message_type in zmq_names.REQUEST_TYPES, \
-                "Request message type expected!"
-            message_id = socket.recv_string()
-            assert message_id != '', "Valid message id expected!"
-            context, message = socket.recv_loaded()
-
-            return self._create_message(context, message, reply_id,
-                                        message_id, socket, message_type)
-        except (zmq.ZMQError, AssertionError, ValueError) as e:
+            message_version = socket.recv_string()
+            assert message_version != b'', "Valid message version expected!"
+
+            receive_request_version = \
+                self._get_receive_request_version(message_version)
+            return receive_request_version(socket)
+        except (zmq.ZMQError, AssertionError, ValueError,
+                zmq_version.UnsupportedMessageVersionError) as e:
             LOG.error(_LE("Receiving message failure: %s"), str(e))
             # NOTE(gdavoian): drop the left parts of a broken message
             if socket.getsockopt(zmq.RCVMORE):
                 socket.recv_multipart()
 
+    def _receive_request_v_1_0(self, socket):
+        reply_id = socket.recv()
+        assert reply_id != b'', "Valid reply id expected!"
+        message_type = int(socket.recv())
+        assert message_type in zmq_names.REQUEST_TYPES, "Request expected!"
+        message_id = socket.recv_string()
+        assert message_id != '', "Valid message id expected!"
+        context, message = socket.recv_loaded()
+
+        return self._create_message(context, message, '1.0', reply_id,
+                                    message_id, socket, message_type)
+
     def cleanup(self):
         LOG.info(_LI("[%s] Destroy DEALER consumer"), self.host)
         self.connection_updater.cleanup()
@@ -127,9 +148,10 @@ class DealerConsumerWithAcks(DealerConsumer):
             ttl=conf.oslo_messaging_zmq.rpc_message_ttl
         )
 
-    def _acknowledge(self, reply_id, message_id, socket):
+    def _acknowledge(self, message_version, reply_id, message_id, socket):
         ack = zmq_response.Ack(message_id=message_id,
-                               reply_id=reply_id)
+                               reply_id=reply_id,
+                               message_version=message_version)
         self.ack_sender.send(socket, ack)
 
     def _reply(self, rpc_message, reply, failure):
@@ -143,8 +165,8 @@ class DealerConsumerWithAcks(DealerConsumer):
         if reply is not None:
             self.reply_sender.send(socket, reply)
 
-    def _create_message(self, context, message, reply_id, message_id, socket,
-                        message_type):
+    def _create_message(self, context, message, message_version, reply_id,
+                        message_id, socket, message_type):
         # drop a duplicate message
         if message_id in self.messages_cache:
             LOG.warning(
@@ -159,7 +181,8 @@ class DealerConsumerWithAcks(DealerConsumer):
             # for the CALL message also try to resend its reply
             # (of course, if it was already obtained and cached).
             if message_type in zmq_names.DIRECT_TYPES:
-                self._acknowledge(reply_id, message_id, socket)
+                self._acknowledge(message_version, reply_id, message_id,
+                                  socket)
             if message_type == zmq_names.CALL_TYPE:
                 self._reply_from_cache(message_id, socket)
             return None
@@ -170,10 +193,11 @@ class DealerConsumerWithAcks(DealerConsumer):
         # be too late to wait until the message will be
         # dispatched and processed by a RPC server
         if message_type in zmq_names.DIRECT_TYPES:
-            self._acknowledge(reply_id, message_id, socket)
+            self._acknowledge(message_version, reply_id, message_id, socket)
 
         return super(DealerConsumerWithAcks, self)._create_message(
-            context, message, reply_id, message_id, socket, message_type
+            context, message, message_version, reply_id,
+            message_id, socket, message_type
         )
 
     def cleanup(self):
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
index fe09bc9..3395f04 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
@@ -22,6 +22,7 @@ from oslo_messaging._drivers.zmq_driver.server.consumers \
 from oslo_messaging._drivers.zmq_driver.server import zmq_incoming_message
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging._i18n import _LE, _LI
 
 LOG = logging.getLogger(__name__)
@@ -34,6 +35,8 @@ class RouterConsumer(zmq_consumer_base.SingleSocketConsumer):
     def __init__(self, conf, poller, server):
         self.reply_sender = zmq_senders.ReplySenderDirect(conf)
         super(RouterConsumer, self).__init__(conf, poller, server, zmq.ROUTER)
+        self._receive_request_versions = \
+            zmq_version.get_method_versions(self, 'receive_request')
         LOG.info(_LI("[%s] Run ROUTER consumer"), self.host)
 
     def _reply(self, rpc_message, reply, failure):
@@ -41,48 +44,66 @@ class RouterConsumer(zmq_consumer_base.SingleSocketConsumer):
             failure = rpc_common.serialize_remote_exception(failure)
         reply = zmq_response.Reply(message_id=rpc_message.message_id,
                                    reply_id=rpc_message.reply_id,
+                                   message_version=rpc_message.message_version,
                                    reply_body=reply,
                                    failure=failure)
         self.reply_sender.send(rpc_message.socket, reply)
         return reply
 
-    def _create_message(self, context, message, reply_id, message_id, socket,
-                        message_type):
+    def _create_message(self, context, message, message_version, reply_id,
+                        message_id, socket, message_type):
         if message_type == zmq_names.CALL_TYPE:
             message = zmq_incoming_message.ZmqIncomingMessage(
-                context, message, reply_id=reply_id, message_id=message_id,
+                context, message, message_version=message_version,
+                reply_id=reply_id, message_id=message_id,
                 socket=socket, reply_method=self._reply
             )
         else:
             message = zmq_incoming_message.ZmqIncomingMessage(context, message)
 
-        LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s",
+        LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s "
+                  "(v%(msg_version)s)",
                   {"host": self.host,
                    "msg_type": zmq_names.message_type_str(message_type),
-                   "msg_id": message_id})
+                   "msg_id": message_id,
+                   "msg_version": message_version})
         return message
 
-    def receive_message(self, socket):
+    def _get_receive_request_version(self, version):
+        receive_request_version = self._receive_request_versions.get(version)
+        if receive_request_version is None:
+            raise zmq_version.UnsupportedMessageVersionError(version)
+        return receive_request_version
+
+    def receive_request(self, socket):
         try:
             reply_id = socket.recv()
             assert reply_id != b'', "Valid reply id expected!"
             empty = socket.recv()
             assert empty == b'', "Empty delimiter expected!"
-            message_type = int(socket.recv())
-            assert message_type in zmq_names.REQUEST_TYPES, \
-                "Request message type expected!"
-            message_id = socket.recv_string()
-            assert message_id != '', "Valid message id expected!"
-            context, message = socket.recv_loaded()
-
-            return self._create_message(context, message, reply_id,
-                                        message_id, socket, message_type)
-        except (zmq.ZMQError, AssertionError, ValueError) as e:
+            message_version = socket.recv_string()
+            assert message_version != b'', "Valid message version expected!"
+
+            receive_request_version = \
+                self._get_receive_request_version(message_version)
+            return receive_request_version(reply_id, socket)
+        except (zmq.ZMQError, AssertionError, ValueError,
+                zmq_version.UnsupportedMessageVersionError) as e:
             LOG.error(_LE("Receiving message failed: %s"), str(e))
             # NOTE(gdavoian): drop the left parts of a broken message
             if socket.getsockopt(zmq.RCVMORE):
                 socket.recv_multipart()
 
+    def _receive_request_v_1_0(self, reply_id, socket):
+        message_type = int(socket.recv())
+        assert message_type in zmq_names.REQUEST_TYPES, "Request expected!"
+        message_id = socket.recv_string()
+        assert message_id != '', "Valid message id expected!"
+        context, message = socket.recv_loaded()
+
+        return self._create_message(context, message, '1.0', reply_id,
+                                    message_id, socket, message_type)
+
     def cleanup(self):
         LOG.info(_LI("[%s] Destroy ROUTER consumer"), self.host)
         super(RouterConsumer, self).cleanup()
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
index c843d3c..2d53489 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
@@ -25,6 +25,7 @@ from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
 from oslo_messaging._drivers.zmq_driver import zmq_socket
 from oslo_messaging._drivers.zmq_driver import zmq_updater
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging._i18n import _LE, _LI
 
 LOG = logging.getLogger(__name__)
@@ -45,9 +46,11 @@ class SubConsumer(zmq_consumer_base.ConsumerBase):
         self.sockets.append(self.socket)
         self.host = self.socket.handle.identity
         self._subscribe_to_topic()
+        self._receive_request_versions = \
+            zmq_version.get_method_versions(self, 'receive_request')
         self.connection_updater = SubscriberConnectionUpdater(
             conf, self.matchmaker, self.socket)
-        self.poller.register(self.socket, self.receive_message)
+        self.poller.register(self.socket, self.receive_request)
         LOG.info(_LI("[%s] Run SUB consumer"), self.host)
 
     def _generate_identity(self):
@@ -61,27 +64,39 @@ class SubConsumer(zmq_consumer_base.ConsumerBase):
         LOG.debug("[%(host)s] Subscribing to topic %(filter)s",
                   {"host": self.host, "filter": topic_filter})
 
-    def _receive_request(self, socket):
-        topic_filter = socket.recv()
+    def _get_receive_request_version(self, version):
+        receive_request_version = self._receive_request_versions.get(version)
+        if receive_request_version is None:
+            raise zmq_version.UnsupportedMessageVersionError(version)
+        return receive_request_version
+
+    def _receive_request_v_1_0(self, topic_filter, socket):
         message_type = int(socket.recv())
+        assert message_type in zmq_names.MULTISEND_TYPES, "Fanout expected!"
         message_id = socket.recv()
         context, message = socket.recv_loaded()
         LOG.debug("[%(host)s] Received on topic %(filter)s message %(msg_id)s "
-                  "%(msg_type)s",
+                  "(v%(msg_version)s)",
                   {'host': self.host,
                    'filter': topic_filter,
                    'msg_id': message_id,
-                   'msg_type': zmq_names.message_type_str(message_type)})
+                   'msg_version': '1.0'})
         return context, message
 
-    def receive_message(self, socket):
+    def receive_request(self, socket):
         try:
-            context, message = self._receive_request(socket)
-            if not message:
-                return None
+            topic_filter = socket.recv()
+            message_version = socket.recv_string()
+            receive_request_version = \
+                self._get_receive_request_version(message_version)
+            context, message = receive_request_version(topic_filter, socket)
             return zmq_incoming_message.ZmqIncomingMessage(context, message)
-        except (zmq.ZMQError, AssertionError) as e:
+        except (zmq.ZMQError, AssertionError, ValueError,
+                zmq_version.UnsupportedMessageVersionError) as e:
             LOG.error(_LE("Receiving message failed: %s"), str(e))
+            # NOTE(gdavoian): drop the left parts of a broken message
+            if socket.getsockopt(zmq.RCVMORE):
+                socket.recv_multipart()
 
     def cleanup(self):
         LOG.info(_LI("[%s] Destroy SUB consumer"), self.host)
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_names.py b/oslo_messaging/_drivers/zmq_driver/zmq_names.py
index 31b2080..3e345df 100644
--- a/oslo_messaging/_drivers/zmq_driver/zmq_names.py
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_names.py
@@ -19,15 +19,17 @@ zmq = zmq_async.import_zmq()
 
 FIELD_MSG_ID = 'message_id'
 FIELD_REPLY_ID = 'reply_id'
+FIELD_MSG_VERSION = 'message_version'
 FIELD_REPLY_BODY = 'reply_body'
 FIELD_FAILURE = 'failure'
 
 
 REPLY_ID_IDX = 0
 EMPTY_IDX = 1
-MESSAGE_TYPE_IDX = 2
-ROUTING_KEY_IDX = 3
-MESSAGE_ID_IDX = 4
+MESSAGE_VERSION_IDX = 2
+MESSAGE_TYPE_IDX = 3
+ROUTING_KEY_IDX = 4
+MESSAGE_ID_IDX = 5
 
 
 DEFAULT_TYPE = 0
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_version.py b/oslo_messaging/_drivers/zmq_driver/zmq_version.py
new file mode 100644
index 0000000..92baf71
--- /dev/null
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_version.py
@@ -0,0 +1,60 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import re
+
+from oslo_messaging._drivers import common as rpc_common
+from oslo_messaging._i18n import _
+
+
+# current driver's version for representing internal message format
+MESSAGE_VERSION = '1.0'
+
+
+class UnsupportedMessageVersionError(rpc_common.RPCException):
+    msg_fmt = _("Message version %(version)s is not supported.")
+
+    def __init__(self, version):
+        super(UnsupportedMessageVersionError, self).__init__(version=version)
+
+
+def get_method_versions(obj, method_name):
+    """Useful function for initializing versioned senders/receivers.
+
+    Returns a dictionary of different internal versions of the given method.
+
+    Assumes that the object has the particular versioned method and this method
+    is public. Thus versions are private implementations of the method.
+
+    For example, for a method 'func' methods '_func_v_1_0', '_func_v_1_5',
+    '_func_v_2_0', etc. are assumed as its respective 1.0, 1.5, 2.0 versions.
+    """
+
+    assert callable(getattr(obj, method_name, None)), \
+        "Object must have specified method!"
+    assert not method_name.startswith('_'), "Method must be public!"
+
+    method_versions = {}
+    for attr_name in dir(obj):
+        if attr_name == method_name:
+            continue
+        attr = getattr(obj, attr_name, None)
+        if not callable(attr):
+            continue
+        match_obj = re.match(r'^_%s_v_(\d)_(\d)$' % method_name, attr_name)
+        if match_obj is not None:
+            version = '.'.join([match_obj.group(1), match_obj.group(2)])
+            method_versions[version] = attr
+
+    return method_versions
diff --git a/oslo_messaging/tests/drivers/zmq/test_pub_sub.py b/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
index da21c60..ec302c6 100644
--- a/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
+++ b/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
@@ -1,4 +1,4 @@
-#    Copyright 2015 Mirantis, Inc.
+#    Copyright 2015-2016 Mirantis, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -28,6 +28,7 @@ from oslo_messaging._drivers.zmq_driver.proxy import zmq_proxy
 from oslo_messaging._drivers.zmq_driver import zmq_address
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._drivers.zmq_driver import zmq_version
 from oslo_messaging.tests.drivers.zmq import zmq_common
 
 load_tests = testscenarios.load_tests_apply_scenarios
@@ -58,15 +59,14 @@ class TestPubSub(zmq_common.ZmqBaseTestCase):
         self.config(group='oslo_messaging_zmq', **kwargs)
 
         self.config(host="127.0.0.1", group="zmq_proxy_opts")
-        self.config(publisher_port="0", group="zmq_proxy_opts")
+        self.config(publisher_port=0, group="zmq_proxy_opts")
 
         self.publisher = zmq_publisher_proxy.PublisherProxy(
             self.conf, self.driver.matchmaker)
-        self.driver.matchmaker.register_publisher(
-            (self.publisher.host, ""))
+        self.driver.matchmaker.register_publisher((self.publisher.host, ''))
 
         self.listeners = []
-        for i in range(self.LISTENERS_COUNT):
+        for _ in range(self.LISTENERS_COUNT):
             self.listeners.append(zmq_common.TestServerListener(self.driver))
 
     def tearDown(self):
@@ -83,10 +83,14 @@ class TestPubSub(zmq_common.ZmqBaseTestCase):
         message = {'method': 'hello-world'}
 
         self.publisher.send_request(
-            [b'', b'', zmq_names.CAST_FANOUT_TYPE,
+            [b"reply_id",
+             b'',
+             six.b(zmq_version.MESSAGE_VERSION),
+             six.b(str(zmq_names.CAST_FANOUT_TYPE)),
              zmq_address.target_to_subscribe_filter(target),
-             b"0000-0000",
-             self.dumps([context, message])])
+             b"message_id",
+             self.dumps([context, message])]
+        )
 
     def _check_listener(self, listener):
         listener._received.wait(timeout=5)
diff --git a/oslo_messaging/tests/drivers/zmq/test_zmq_version.py b/oslo_messaging/tests/drivers/zmq/test_zmq_version.py
new file mode 100644
index 0000000..9b01894
--- /dev/null
+++ b/oslo_messaging/tests/drivers/zmq/test_zmq_version.py
@@ -0,0 +1,63 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_messaging._drivers.zmq_driver import zmq_version
+from oslo_messaging.tests import utils as test_utils
+
+
+class Doer(object):
+
+    def __init__(self):
+        self.x = 1
+        self.y = 2
+        self.z = 3
+
+    def _sudo(self):
+        pass
+
+    def do(self):
+        pass
+
+    def _do_v_1_1(self):
+        pass
+
+    def _do_v_2_2(self):
+        pass
+
+    def _do_v_3_3(self):
+        pass
+
+
+class TestZmqVersion(test_utils.BaseTestCase):
+
+    def setUp(self):
+        super(TestZmqVersion, self).setUp()
+        self.doer = Doer()
+
+    def test_get_unknown_attr_versions(self):
+        self.assertRaises(AssertionError, zmq_version.get_method_versions,
+                          self.doer, 'qwerty')
+
+    def test_get_non_method_attr_versions(self):
+        for attr_name in vars(self.doer):
+            self.assertRaises(AssertionError, zmq_version.get_method_versions,
+                              self.doer, attr_name)
+
+    def test_get_private_method_versions(self):
+        self.assertRaises(AssertionError, zmq_version.get_method_versions,
+                          self.doer, '_sudo')
+
+    def test_get_public_method_versions(self):
+        do_versions = zmq_version.get_method_versions(self.doer, 'do')
+        self.assertEqual(['1.1', '2.2', '3.3'], sorted(do_versions.keys()))