Add LatestRevisionReady condition to Configuration

[mattmoor]

Per the API specification, Configuration should have a condition like this:

  conditions:
  - type: LatestRevisionReady
    status: False
    reason: ContainerMissing
    message: "Unable to start because container is missing and build failed."

It would be defined here and effective serve to surface the status of the latestCreatedRevisions progression toward readiness.

[mattmoor]

Look here at the various reasons we might hit this.

[johnugeorge]

I am little confused here. At some point of time, there can be multiple revisions of a configuration that haven't become ready yet. when we say this condition as LatestRevisionReady->False, are we referring only to the status of the latestCreatedRevisionName and leave out other previous revisions(even when they are not ready yet)?
@mattmoor @grantr

[grantr]

when we say this condition as LatestRevisionReady->False, are we referring only to the status of the latestCreatedRevisionName and leave out other previous revisions(even when they are not ready yet)?

I believe the answer to this is yes. Revisions older than the latest are not implicitly targetable in Routes using the Configuration's name, so there's no existing need to expose their status on the Configuration itself. Conversely, the latest revision is implicitly targetable in Routes, so it is useful to expose its status on the Configuration.

Does that make sense?

[evankanderson]

Additionally, the latestCreatedRevision is presumably equivalent to the "current status" of the Configuration. In source control terms, this is the state of HEAD.

The LatestRevisionReady property is akin to answering the question "do tests pass at HEAD". In particular, this can be useful for surfacing a warning in UI/CLI tools during a deployment that the base which the deployer is working off of may not be good. (It may also simply not have had time to become Ready.)

A hypothetical UX workflow on a Configuration when LatestRevisionReady is False might look like:

$ elactl update --set_env SQLDB="jdbc:sqlserver://prodsql:1433;databaseName=publisher"
Deploying to [thumbnailer].
Warning! The most recent thumbnailer is not ready (BuildFailed): "Unable to resolve qithub.com/foo/baz"
The most recent ready thumbnailer was: thumbnailer-4acbe32 from March 28.
Do you want to roll back before updating [Y/n]? Y
Copying configuration from thumbnailer-4acbe32 and applying changes... done!
.... [Normal flow of things becoming ready]

[bobcatfish]

@mattmoor @evankanderson should this be added to the conformance tests?

[evankanderson]

Yes, thanks!