Pushing a non existent tag doesn't raise an exception

I get this error in the error output but no exception is raised:

{"status":"The push refers to repository [485757098324.dkr.ecr.us-east-1.amazonaws.com/ssh_proxy]"}
{"errorDetail":{"message":"An image does not exist locally with the tag: 485757098324.dkr.ecr.us-east-1.amazonaws.com/ssh_proxy"},"error":"An image does not exist locally with the tag: 485757098324.dkr.ecr.us-east-1.amazonaws.com/ssh_proxy"}

Unlike related issue #1772 there’s really no excuse here, since this error can be detected even if trying to push to a black box, while #1772 requires understanding the output of a repo server.

Also worth mentioning that the docker push command WILL return an error code in this case. So actually the docker push command gives MORE info than the SDK function. Since the docker push command gives output + error code. While the SDK function only gives output 😦

(Not saying the function needs to BC break and return two values, just that it needs to raise exceptions when appropriate)

[thaJeztah]

@chris-crone https://github.com/moby/moby/pull/38467 likely won’t help in this case, because the daemon sent a 200 status before it detects the error; https://github.com/moby/moby/pull/38467 will make the client return the status code (instead of just a plain error).

I can try if waiting to send the “The push refers to repository” message until after the initial error detection was done could allow us to send a proper status code (and prevent the 200 status from being sent before that).

FWIW, I do think we still need the python sdk to detect errors if an errorDetail arrives; even though this initial error check could make it possible to send a 4xx status code, there may be situations where an error occurs further down the push (e.g. push is in progress, but the registry returns a failure). Due to this endpoint returning a stream, the status code cannot be updated at that point.

Also, as far as this specific error is concerned, the Docker Engine really should do some trivial validation and detect if a tag doesn’t exist locally and send a 4xx HTTP response rather than attempt a push anyway.

Also see the above; in this case it looks like the validation is actually done before the actual push happens (but the initial message was already sent; I’ll try and see if that particular case can be resolved)

[milas]

@caeus There is no update on this behavior in docker-py. Currently, the library exposes the Engine API as-is here. The engine will return a 200 if the push is able to start, and then streams push status back in the response. If an error is hit during push, that will be reflected in the events. The push_wrapper example from this comment shows how to handle this API response.