Add rpc to openstack-common.

Implements blueprint common-rpc.

This patch imports nova.rpc to openstack-common.  All of the necessary
changes to the core code to make it compatible with openstack-common
have been done in nova, so the only changes made here are to imports.

There are more changes made to the tests, but nothing that changes the
core functionality of the tests.

Change-Id: I17330aa4adfd0f22c449a2376833c7fe9dfd0cf1

1 files changed, 161 insertions, 0 deletions

diff --git a/openstack/common/rpc/proxy.py b/openstack/common/rpc/proxy.py
new file mode 100644
index 0000000..4f4dff5
--- /dev/null
+++ b/openstack/common/rpc/proxy.py
@@ -0,0 +1,161 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 Red Hat, 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.
+
+"""
+A helper class for proxy objects to remote APIs.
+
+For more information about rpc API version numbers, see:
+    rpc/dispatcher.py
+"""
+
+
+from openstack.common import rpc
+
+
+class RpcProxy(object):
+    """A helper class for rpc clients.
+
+    This class is a wrapper around the RPC client API.  It allows you to
+    specify the topic and API version in a single place.  This is intended to
+    be used as a base class for a class that implements the client side of an
+    rpc API.
+    """
+
+    def __init__(self, topic, default_version):
+        """Initialize an RpcProxy.
+
+        :param topic: The topic to use for all messages.
+        :param default_version: The default API version to request in all
+               outgoing messages.  This can be overridden on a per-message
+               basis.
+        """
+        self.topic = topic
+        self.default_version = default_version
+        super(RpcProxy, self).__init__()
+
+    def _set_version(self, msg, vers):
+        """Helper method to set the version in a message.
+
+        :param msg: The message having a version added to it.
+        :param vers: The version number to add to the message.
+        """
+        msg['version'] = vers if vers else self.default_version
+
+    def _get_topic(self, topic):
+        """Return the topic to use for a message."""
+        return topic if topic else self.topic
+
+    @staticmethod
+    def make_msg(method, **kwargs):
+        return {'method': method, 'args': kwargs}
+
+    def call(self, context, msg, topic=None, version=None, timeout=None):
+        """rpc.call() a remote method.
+
+        :param context: The request context
+        :param msg: The message to send, including the method and args.
+        :param topic: Override the topic for this message.
+        :param timeout: (Optional) A timeout to use when waiting for the
+               response.  If no timeout is specified, a default timeout will be
+               used that is usually sufficient.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: The return value from the remote method.
+        """
+        self._set_version(msg, version)
+        return rpc.call(context, self._get_topic(topic), msg, timeout)
+
+    def multicall(self, context, msg, topic=None, version=None, timeout=None):
+        """rpc.multicall() a remote method.
+
+        :param context: The request context
+        :param msg: The message to send, including the method and args.
+        :param topic: Override the topic for this message.
+        :param timeout: (Optional) A timeout to use when waiting for the
+               response.  If no timeout is specified, a default timeout will be
+               used that is usually sufficient.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: An iterator that lets you process each of the returned values
+                  from the remote method as they arrive.
+        """
+        self._set_version(msg, version)
+        return rpc.multicall(context, self._get_topic(topic), msg, timeout)
+
+    def cast(self, context, msg, topic=None, version=None):
+        """rpc.cast() a remote method.
+
+        :param context: The request context
+        :param msg: The message to send, including the method and args.
+        :param topic: Override the topic for this message.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: None.  rpc.cast() does not wait on any return value from the
+                  remote method.
+        """
+        self._set_version(msg, version)
+        rpc.cast(context, self._get_topic(topic), msg)
+
+    def fanout_cast(self, context, msg, version=None):
+        """rpc.fanout_cast() a remote method.
+
+        :param context: The request context
+        :param msg: The message to send, including the method and args.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: None.  rpc.fanout_cast() does not wait on any return value
+                  from the remote method.
+        """
+        self._set_version(msg, version)
+        rpc.fanout_cast(context, self.topic, msg)
+
+    def cast_to_server(self, context, server_params, msg, topic=None,
+            version=None):
+        """rpc.cast_to_server() a remote method.
+
+        :param context: The request context
+        :param server_params: Server parameters.  See rpc.cast_to_server() for
+               details.
+        :param msg: The message to send, including the method and args.
+        :param topic: Override the topic for this message.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: None.  rpc.cast_to_server() does not wait on any
+                  return values.
+        """
+        self._set_version(msg, version)
+        rpc.cast_to_server(context, server_params, self._get_topic(topic), msg)
+
+    def fanout_cast_to_server(self, context, server_params, msg, version=None):
+        """rpc.fanout_cast_to_server() a remote method.
+
+        :param context: The request context
+        :param server_params: Server parameters.  See rpc.cast_to_server() for
+               details.
+        :param msg: The message to send, including the method and args.
+        :param version: (Optional) Override the requested API version in this
+               message.
+
+        :returns: None.  rpc.fanout_cast_to_server() does not wait on any
+                  return values.
+        """
+        self._set_version(msg, version)
+        rpc.fanout_cast_to_server(context, server_params, self.topic, msg)