openstack
/
oslo.messaging
Code Issues Proposed changes

Add support for multiple namespaces in Targets 

In order for projects to use the namespace property of Targets
in a backwards compatible way (To support rolling upgrades),
a Target may now belong to more than a single namespace (i.e.
'namespace1' and None). This way, if the server is upgraded first,
the version that introduces namespaces to a project will place
the server RPC methods in ['some_namespace', None]. Pre-upgrade
agents will send messages in the null namespace while post-upgrade
agents will send messages in 'some_namespace', and both will be
accepted.

Change-Id: I713fe9228111c36aa3f7fb95cbd59c99100e8c96
Closes-Bug: #1430984
This commit is contained in:
Assaf Muller 2015-03-11 21:39:54 -04:00
parent 8836d3e43c
commit 3be95adceb
3 changed files with 21 additions and 2 deletions
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2
oslo_messaging/rpc/dispatcher.py
View File

@ -111,7 +111,7 @@ class RPCDispatcher(object):
@staticmethod
def _is_namespace(target, namespace):
return namespace == target.namespace
return namespace in target.accepted_namespaces
@staticmethod
def _is_compatible(target, version):

9
oslo_messaging/target.py
View File

@ -57,16 +57,23 @@ class Target(object):
servers listening on a topic by setting fanout to ``True``, rather than
just one of them.
:type fanout: bool
:param legacy_namespaces: A server always accepts messages specified via
the 'namespace' parameter, and may also accept messages defined via
this parameter. This option should be used to switch namespaces safely
during rolling upgrades.
:type legacy_namespaces: list of strings
"""
def __init__(self, exchange=None, topic=None, namespace=None,
version=None, server=None, fanout=None):
version=None, server=None, fanout=None,
legacy_namespaces=None):
self.exchange = exchange
self.topic = topic
self.namespace = namespace
self.version = version
self.server = server
self.fanout = fanout
self.accepted_namespaces = [namespace] + (legacy_namespaces or [])
def __call__(self, **kwargs):
for a in ('exchange', 'topic', 'namespace',

12
oslo_messaging/tests/rpc/test_dispatcher.py
View File

@ -89,6 +89,18 @@ class TestDispatcher(test_utils.BaseTestCase):
dispatch_to=None,
ctxt={}, msg=dict(method='foo', version='3.2'),
success=False, ex=oslo_messaging.UnsupportedVersion)),
('message_in_null_namespace_with_multiple_namespaces',
dict(endpoints=[dict(namespace='testns',
legacy_namespaces=[None])],
dispatch_to=dict(endpoint=0, method='foo'),
ctxt={}, msg=dict(method='foo', namespace=None),
success=True, ex=None)),
('message_in_wrong_namespace_with_multiple_namespaces',
dict(endpoints=[dict(namespace='testns',
legacy_namespaces=['second', None])],
dispatch_to=None,
ctxt={}, msg=dict(method='foo', namespace='wrong'),
success=False, ex=oslo_messaging.UnsupportedVersion)),
]
def test_dispatcher(self):