Switch to curator-go treecache

[brian-brazil]

The treecache implementation used in our zookeeper service discovery was something I wrote as none existed in Go at the time. I attempted to get it upstreamed into a more appropriate library, but it appears that https://github.com/curator-go/curator/ is now the standard.

I think we should switch to that library rather than continuing to maintain our own version.

[StephanErb]

This sounds like a good idea. The current implementation is collapsing regularly due to shortcomings of the used ZK go library (samuel/go-zookeeper#121, samuel/go-zookeeper#133)

[brian-brazil]

curator-go relies on the same ZK library as what we have - there's only one of them in Go as far as I'm aware.

[StephanErb]

I have filed samuel/go-zookeeper#165 as a desperate attempt. Let's see what comes out of it.

[cstyan]

@brian-brazil I'll give this a shot. Should I branch from master or 2.0?

[brian-brazil]

Master.

[elifkus]

@brian-brazil

I looked into the go-curator TreeCache implementation here. https://github.com/curator-go/curator/blob/master/recipes/cache/tree_cache.go

You’d like to remove this code https://github.com/prometheus/prometheus/blob/master/util/treecache/treecache.go and use the code above. Am I right?

The curator tree_cache implementation has a dependency on the curator client. Do you want to use curator itself as well?

(I couldn't find an implementation of tree_cache in go-curator that doesn’t have a dependency on the curator client.)

[brian-brazil]

Am I right?

Yes.

The curator tree_cache implementation has a dependency on the curator client. Do you want to use curator itself as well?

If that's what's required.

[elifkus]

curator-go looks unmaintained. This issue Fix various race conditions #4 especially this comment makes me think that using curator-go is not a good idea.