[openstack-dev] [nova] Question to clarify versioned notifications

Matt Riedemann mriedemos at gmail.com
Tue Mar 7 19:42:03 UTC 2017


While digging through nova code today to compare versioned and 
unversioned notifications, and reading specs and seeing how seachlight 
handles nova notifications, I noticed that the unversioned notifications 
have a "compute." prefix in the name. The versioned notifications do not.

It also took me awhile but I also sorted out that unversioned 
notifications are on the 'notifications' topic which is the default in 
oslo.messaging ([oslo_messaging_notifications]topics) and versioned 
notifications are on the 'versioned_notifications' topic.

My question is, was it intentional to drop the "compute." prefix from 
the event type on the versioned notifications? I didn't see anything 
specifically stating that in the original spec [1].

Since the notifications are on independent topics it probably doesn't 
matter. I was just thinking about this from the searchlight perspective 
because they don't support nova versioned notifications yet and already 
have code to map the "compute." event types [2], I wasn't sure if they 
could re-use that and just listen on the 'versioned_notifications' 
topic. In talking with Steve McLellan it doesn't sound like the 
different event types format will be an issue.

[1] 
https://specs.openstack.org/openstack/nova-specs/specs/mitaka/implemented/versioned-notification-api.html
[2] 
https://github.com/openstack/searchlight/blob/2.0.0/searchlight/elasticsearch/plugins/nova/notification_handler.py#L82

-- 

Thanks,

Matt Riedemann



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