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Diffstat (limited to 'openstack/common/rpc/proxy.py')
| -rw-r--r-- | openstack/common/rpc/proxy.py | 161 |
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) |