Verify Endpoint.Info() before accessing it

[aboch]

• During concurrent stress operations in multi-host environment, it is possible to run into a nil EndpointInfo when running docker network ls. It is a valid situation. It just means the endpoint is no longer available in the datastore.

Signed-off-by: Alessandro Boch aboch@docker.com

[calavera]

LGTM

[cpuguy83]

This is OK, but I think it's better to return a nil, err instead of nil and then always checking if the thing is nil.
The error type isn't necessarily for real/hard error cases that we can't come back from, it can be used to signify these types of things, ie "this thing you asked for doesn't actually exist".
This would prevent cases like this where it's only returning one thing so we just assume we're good to use it.

[aboch]

@cpuguy83 Makes sense, but that would be a public API change.

[cpuguy83]

public API of what?

[aboch]

Libnetwork package API. We have been trying not to change existing API in libentwork, not only the ones interfacing with remote drivers. Sure the non driver interfacing API can be changed, given daemon is probably going to be the only client.

[cpuguy83]

LGTM.

Yes, I get we don't want to change the driver API. Package API should be fine to change as this should be versioned by checkouts.

[thaJeztah]

@cpuguy83 @aboch please check if PRs need to be added to the 1.9.1 milestone when merging, so that we don't forget.

[aboch]

@thaJeztah Yes, please. This should be added to 1.9.1.

[thaJeztah]

Thanks! If you see another PR that should be considered, feel free to ping me or another maintainer ❤️