depend directly on oslo.messaging

[Steve Martinelli]

Currently oslo.messaging is treated as "optional" (listed in test-requirements), and work is being done to make it truly optional using setuptool's extras dependencies [1].

Most openstack projects that use keystonemiddleware already depend on oslo.messaging also. Using codesearch, 53 projects depend on keystonemiddleware, only 12 of which do not depend directly on oslo.messaging.

I am proposing that we use oslo.messaging directly in keystonemiddleware, it'll remove special handling in audit middleware, if it's not configured we can write to a log file (as is the case now)

[1] https://bugs.launchpad.net/keystonemiddleware/+bug/1540115

[Steve Martinelli (stevemar)]

List of projects that use keystonemiddleware and do *not* use oslo.messaging:

distil
surveil
cue
ekko
freezer-api
fuel-ostf
fuel-web
ironic-inspector
marshal
monasca-api
monasca-log-api
zaqar

[Jamie Lennox (jamielennox)]

I'm ok with this being a direct dependency. I think the burden of the extra download is negated by the confusion of having to do the keystonemiddleware[audit_notifications] extras. It's an already widely used and packaged dependency.

[Steve Martinelli (stevemar)]

We decided to not go with this approach and keep it as an optional dependency.