Publish to Pub/Sub after a rollout/rollback have occurred

[gvso]

In order to allow other functionality around the Release Manager, we need to provide a way to subscribe to events. This will allow things like smoke tests and notification features. The following format could be useful:

{
    "event": "rollout", // or "rollback"
    "candidateRevisionName": "hello-002-abc",
    "candidateRevisionPercent": 50,
    "candidateRevisionURL": "https://candidate---hello-wh32u62c4l-ue.a.run.app",
    "candidateWasPromotedToStable": false,
    "service": {json}
}

[ahmetb]

@steren wdyt of the event format above? We want to optionally do:

 --notify-pubsub=projects/x/topics/y

and let users push rollout and rollback notifications for them to be able to run smoke tests (or do other things like ChatOps). Is the information above sufficient for those cases?

[steren]

Seems like a good idea. Trying to build something real with these is the best way to see if the event contains the info you would need.

[gvso]

@ahmetb Why do we need to pass the project as part of the flag? We could use the project ID we already autodetect (or asked for with -project)?

[ahmetb]

It's possible to push to topics in another project and it's a common use case.