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.
"""
v = vers if vers else self.default_version
if (self.version_cap and not
rpc_common.version_is_compatible(self.version_cap, v)):
raise rpc_common.RpcVersionCapError(version=self.version_cap)
msg['version'] = v
def dispatch(self, ctxt, version, method, namespace, **kwargs):
"""Dispatch a message based on a requested version.
:param ctxt: The request context
:param version: The requested API version from the incoming message
:param method: The method requested to be called by the incoming
message.
:param namespace: The namespace for the requested method. If None,
the dispatcher will look for a method on a callback
object with no namespace set.
:param kwargs: A dict of keyword arguments to be passed to the method.
:returns: Whatever is returned by the underlying method that gets
called.
"""
if not version:
version = '1.0'
had_compatible = False
for proxyobj in self.callbacks:
# Check for namespace compatibility
try:
cb_namespace = proxyobj.RPC_API_NAMESPACE
except AttributeError:
cb_namespace = None
if namespace != cb_namespace:
continue
# Check for version compatibility
try:
rpc_api_version = proxyobj.RPC_API_VERSION
except AttributeError:
rpc_api_version = '1.0'
is_compatible = rpc_common.version_is_compatible(rpc_api_version,
version)
had_compatible = had_compatible or is_compatible
if not hasattr(proxyobj, method):
continue
if is_compatible:
return getattr(proxyobj, method)(ctxt, **kwargs)
if had_compatible:
raise AttributeError("No such RPC function '%s'" % method)
else:
raise rpc_common.UnsupportedRpcVersion(version=version)