We need to support deprecated transport driver configurations like:
rpc_backend = nova.rpc.impl_kombu
i.e. 'nova.rpc.impl_kombu' is a deprecated alias for 'rabbit'.
Initially, we supported this by adding the aliases to each project's
setup.cfg:
oslo.messaging.drivers =
nova.rpc.impl_kombu = oslo.messaging._drivers.impl_rabbit:RabbitDriver
However, this means that code like this:
url = str(TransportURL(conf))
generates a bogus URL string like:
nova.rpc.impl_kombu://...
We need to apply these transport aliases when we load drivers, but also
when we create transport URLs from configuration containing potentially
deprecated aliases.
To enable that, add an aliases parameter to TransportURL(),
TransportURL.parse() and get_transport().
blueprint: transport-aliases
Change-Id: Ifce68ff62746c2a363c719417a2bd0a78ee025dd
Handle e.g. foo://u:p@/bar. Right now we get:
IndexError: string index out of range
from:
if hostname[0] == '[':
Change-Id: I0bccebb14ad1d37862955e8988d160240bd1cf6d
Just copies code from Nova's cells code.
See I6b18f7643ab694f5ff34206b80865c40b1ec2680 for where this code was
first introduced.
Change-Id: If9b1503ed47f5910c0ab44edfbe3f42fcce9bf18
Nova's cells/rpc_driver.py has some code which allows user of the REST
API to update elements of a cell's transport URL (say, the host name of
the message broker) stored in the database. To achieve this, it has
a parse_transport_url() method which breaks the URL into its constituent
parts and an unparse_transport_url() which re-forms it again after
updating some of its parts.
This is all fine and, since it's fairly specialized, it wouldn't be a
big deal to leave this code in Nova for now ... except the unparse
method looks at CONF.rpc_backend to know what scheme to use in the
returned URL if now backend was specified.
oslo.messaging registers the rpc_backend option, but the ability to
reference any option registered by the library should not be relied upon
by users of the library. Imagine, for instance, if we renamed the option
in future (with backwards compat for old configurations), then this
would mean API breakage.
So, long story short - an API along these lines makes some sense, but
especially since not having it would mean we'd need to add some way to
query the name of the transport driver.
In this commit, we add a simple new TransportURL class:
>>> url = messaging.TransportURL.parse(cfg.CONF, 'foo:///')
>>> str(url), url
('foo:///', <TransportURL transport='foo'>)
>>> url.hosts.append(messaging.TransportHost(hostname='localhost'))
>>> str(url), url
('foo://localhost/', <TransportURL transport='foo', hosts=[<TransportHost hostname='localhost'>]>)
>>> url.transport = None
>>> str(url), url
('kombu://localhost/', <TransportURL transport='kombu', hosts=[<TransportHost hostname='localhost'>]>)
>>> cfg.CONF.set_override('rpc_backend', 'bar')
>>> str(url), url
('bar://localhost/', <TransportURL transport='bar', hosts=[<TransportHost hostname='localhost'>]>)
The TransportURL.parse() method equates to parse_transport_url() and
TransportURL.__str__() equates to unparse_transport().
The transport drivers are also updated to take a TransportURL as a
required argument, which simplifies the handling of transport URLs in
the drivers.
Change-Id: Ic04173476329858e4a2c2d2707e9d4aeb212d127
My original thinking was that if you're using the exchange name to
separate two instances of the applications (so their queues don't
collide) then the exchange name is pretty key to transport
configuration. In fact, it's really a virtual host that you'd use for
this (at least in the case of rabbit and qpid).
Also, Nova's cells code has already moved ahead with the assumption that
the path specifies a virtual host, so it'd only make sense to deviate
from that if there was a really good reason to.
Change-Id: Ic8b5dc3538b6b17afec524047acc2efa76366377
