Stop using nova.exception from nova.rpc.

This patch is a part of continuing to remove dependencies from nova.rpc
on the rest of nova.  One RPC related exception was defined in
nova.exception, so that was moved to nova.rpc.common where the rest of
them live.  These exceptions were changed to no longer use NovaException
as their base.  Instead, there is a new RPCException base.

One other change that should be reviewed closely is the removal of using
nova.exception.wrap_exception() in nova.rpc.amqp.  As far as I can tell,
this didn't actually do anything since nothing was being passed in to
wrap_exception().

Change-Id: I36ff7c05ab0467ad8506b56d561c532eadf8dff8

3 files changed, 29 insertions, 10 deletions

diff --git a/nova/exception.py b/nova/exception.py
index c1d02faaa..af4850367 100644
--- a/nova/exception.py
+++ b/nova/exception.py
@@ -282,10 +282,6 @@ class InvalidCidr(Invalid):
     message = _("Invalid cidr %(cidr)s.")
 
 
-class InvalidRPCConnectionReuse(Invalid):
-    message = _("Invalid reuse of an RPC connection.")
-
-
 class InvalidUnicodeParameter(Invalid):
     message = _("Invalid Parameter: "
                 "Unicode is not supported by the current database.")
diff --git a/nova/rpc/amqp.py b/nova/rpc/amqp.py
index 798a5f36e..b0a0d5d12 100644
--- a/nova/rpc/amqp.py
+++ b/nova/rpc/amqp.py
@@ -34,7 +34,6 @@ from eventlet import pools
 from eventlet import semaphore
 
 from nova import context
-from nova import exception
 from nova import log as logging
 from nova.openstack.common import excutils
 from nova.openstack.common import local
@@ -141,7 +140,7 @@ class ConnectionContext(rpc_common.Connection):
         if self.connection:
             return getattr(self.connection, key)
         else:
-            raise exception.InvalidRPCConnectionReuse()
+            raise rpc_common.InvalidRPCConnectionReuse()
 
 
 def msg_reply(conf, msg_id, connection_pool, reply=None, failure=None,
@@ -250,7 +249,6 @@ class ProxyCallback(object):
             return
         self.pool.spawn_n(self._process_data, ctxt, method, args)
 
-    @exception.wrap_exception()
     def _process_data(self, ctxt, method, args):
         """Thread that magically looks for a method on the proxy
         object and calls it.
diff --git a/nova/rpc/common.py b/nova/rpc/common.py
index 23a191a9b..d15d1f3f1 100644
--- a/nova/rpc/common.py
+++ b/nova/rpc/common.py
@@ -21,7 +21,6 @@ import copy
 import sys
 import traceback
 
-from nova import exception
 from nova import log as logging
 from nova.openstack.common import cfg
 from nova.openstack.common import importutils
@@ -31,7 +30,29 @@ from nova.openstack.common import jsonutils
 LOG = logging.getLogger(__name__)
 
 
-class RemoteError(exception.NovaException):
+class RPCException(Exception):
+    message = _("An unknown RPC related exception occurred.")
+
+    def __init__(self, message=None, **kwargs):
+        self.kwargs = kwargs
+
+        if not message:
+            try:
+                message = self.message % kwargs
+
+            except Exception as e:
+                # kwargs doesn't match a variable in the message
+                # log the issue and the kwargs
+                LOG.exception(_('Exception in string format operation'))
+                for name, value in kwargs.iteritems():
+                    LOG.error("%s: %s" % (name, value))
+                # at least get the core message out if something happened
+                message = self.message
+
+        super(RPCException, self).__init__(message)
+
+
+class RemoteError(RPCException):
     """Signifies that a remote class has raised an exception.
 
     Contains a string representation of the type of the original exception,
@@ -51,7 +72,7 @@ class RemoteError(exception.NovaException):
                                           traceback=traceback)
 
 
-class Timeout(exception.NovaException):
+class Timeout(RPCException):
     """Signifies that a timeout has occurred.
 
     This exception is raised if the rpc_response_timeout is reached while
@@ -60,6 +81,10 @@ class Timeout(exception.NovaException):
     message = _("Timeout while waiting on RPC response.")
 
 
+class InvalidRPCConnectionReuse(RPCException):
+    message = _("Invalid reuse of an RPC connection.")
+
+
 class Connection(object):
     """A connection, returned by rpc.create_connection().