callback system

[alfredodeza]

From @alfredodeza on May 24, 2016 18:59

Whenever a repository is fully built and ready to be consumed, it would be nice to be able to define a URL to get a POST with metadata information about the repository:

• distro
• distro version(s)
• ref (and sha1?)
• architecture
• timestamp(s)

This would help if a separate system is in charge of understanding what has been built. For testing purposes it is crucial to be able to know what distro versions at what sha1 are ready to be consumed.

Copied from original issue: ceph/mita#74

[alfredodeza]

From @ktdreyer on May 24, 2016 19:29

Internally in Red Hat, IT and engineering is centering around using a message bus (AMPQ) to coordinate these sort of things with the build system. So Koji (Brew, internally) publishes messages to this bus, and other things (Jenkins or whatever) can subscribe to the bus to consume these messages and trigger other events.

Just an idea!

[alfredodeza]

Also should support the following events:

• requested repo to be created
• repo started to be built
• repo has been completed / is ready
• repo failed to be built (include error/traceback payload?)

[alfredodeza]

The notification/callback scheme needs to be very robust and fully asynchronous. I imagine a new queue with a celery worker dealing with notifications.

Such a scheme would allow for retrying broken requests for example (up to a configurable maximum), and would prevent the normal flow of code from waiting until a request is properly processed.