Trove-rpc-versioning

Intro

This page describes the intent to implement oslo messaging's API Version Negotiation in Trove

Oslo

Oslo/Messaging#API_Version_Negotiation

Goals

• Prevent backward incompatibility between Trove components.
• Reduce the need for downtime during deployments

Work

• Keep track of a "version history" in comments in the code
• Update trove calls to the openstack.commom.rpc client to include a version cap param. (This is already supported in the client)
• Document the use cases and examples of how to add/modify API calls

Config

• We may need to put the version caps in the config

https://github.com/openstack/nova/blob/master/nova/baserpc.py

   def __init__(self, topic):
        super(BaseAPI, self).__init__()
        target = messaging.Target(topic=topic,
                                  namespace=_NAMESPACE,
                                  version='1.0')
        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.baseapi,
                                               CONF.upgrade_levels.baseapi)
        self.client = rpc.get_client(target, version_cap=version_cap)