Empty Consul services list causing program to hang in ConsulNameResolver

[msay-via]

Hey, I am having an issue where if Consul is running but no services are registered, then the NameResolver.Listener has no addresses to resolve on, which causes an infinite loop.

It looks like this functionality was introduced in this commit:
2e4f87b#diff-d1f9de41881a455d693a042b740981ff

Can anyone tell me why? Just out of curiosity. Currently this is breaking our unit tests if someone has Consul running on their local machine (though this is probably indicative of a larger architectural problem that I have yet to solve...) a quick fix would be to allow the listener to return an empty list.

Thanks!
Mike

[mjpitz]

So looking at gh-7, the intent was to be able to leverage a cached read. There was some similar functionality this was modeled off of. I'm curious if that cache is necessary.

[mjpitz]

@msay-via : can you provide any more context around this? In something like a unit test, I'd expect you to use an InProcess solution. Having external service dependencies in unit tests can generally be problematic.

[msay-via]

Hey, the unit test scenario is secondary. This really causes issues when the service is not in Consul.

Consul is able to fetch the list but because it's empty for that service, the listener isn't updated. The fact that no service can be resolved and returned to the Client requesting means the whole application blocks.

[mjpitz]

Apologies I didn't get back to this sooner. Was working hard on preparing for a conference. I should be able to resolve this today.

[mjpitz]

@msay-via : PR up for review. I'll follow up once it's merged and published.