clientv3: Fix grpc-go(v1.27.0) incompatible changes to balancer/resolver.

[eddycjy]

clientv3: Fix grpc-go (v1.27.0) incompatible modification of balancer/resolver API.

Modify the API changed by balancer / resolver to ensure consistency with grpc-go (v1.27.0), otherwise clientv3 will not be able to be pulled by go mod, which will affect the direct use of users.

References:

1. balancer/resolver: remove temporary backward-compatibility type aliases
2. Notice: Upcoming Experimental Balancer/Resolver API Changes

Fixes #11563

[codecov-io]

Codecov Report

Merging #11564 into master will increase coverage by 1.51%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #11564      +/-   ##
==========================================
+ Coverage   64.39%   65.91%   +1.51%     
==========================================
  Files         403      401       -2     
  Lines       38097    36568    -1529     
==========================================
- Hits        24534    24105     -429     
+ Misses      11913    10958     -955     
+ Partials     1650     1505     -145

Impacted Files	Coverage Δ
clientv3/balancer/resolver/endpoint/endpoint.go	84.48% <100%> (+1.87%)	⬆️
clientv3/balancer/picker/err.go	100% <100%> (ø)	⬆️
clientv3/balancer/picker/roundrobin_balanced.go	100% <100%> (ø)	⬆️
auth/options.go	35% <0%> (-57.5%)	⬇️
clientv3/balancer/utils.go	53.84% <0%> (-46.16%)	⬇️
client/client.go	47.71% <0%> (-36.28%)	⬇️
pkg/transport/timeout_conn.go	60% <0%> (-20%)	⬇️
auth/jwt.go	51.68% <0%> (-16.89%)	⬇️
etcdserver/api/v3rpc/util.go	51.61% <0%> (-16.13%)	⬇️
etcdserver/api/membership/store.go	60.68% <0%> (-15.67%)	⬇️
... and 121 more

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[jingyih]

cc @jpbetz @gyuho

[eddycjy]

@jpbetz @gyuho @jingyih ping review.

[jpbetz]

Thanks @eddycjy. Would you also update the changelog (3.5 since this is on master) with a clientv3 line item about this change? Please include which grpc versions are compatible and which are incompatible (they're overlapping ranges since there was a period of backward compatibility via the typerefs).

[eddycjy]

@jpbetz Thanks for your reply and reminder, I have submitted CHANGELOG-3.5.

[jpbetz]

Next time lets include the changelog update in the same PR as the main change. But I'm okay with separate for this issue since they are both already open.

LGTM

[jpbetz]

@gyuho WDYT?

[satyajituk]

I get the following error when I simply try to go build main.go in a program which uses "go.etcd.io/etcd/clientv3".

# github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
../../../../pkg/mod/github.com/coreos/etcd@v3.3.18+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:114:78: undefined: resolver.BuildOption
../../../../pkg/mod/github.com/coreos/etcd@v3.3.18+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:182:31: undefined: resolver.ResolveNowOption
# github.com/coreos/etcd/clientv3/balancer/picker
../../../../pkg/mod/github.com/coreos/etcd@v3.3.18+incompatible/clientv3/balancer/picker/err.go:37:44: undefined: balancer.PickOptions
../../../../pkg/mod/github.com/coreos/etcd@v3.3.18+incompatible/clientv3/balancer/picker/roundrobin_balanced.go:55:54: undefined: balancer.PickOptions

Will this PR solve the issue?

[skyjia]

LGTM 👍

[ecifreo]

Any ETA on merging this? We are hitting the go mod dependency issue.

[gdbelvin]

Any ETA on releasing 3.3.19? We are also hitting the go mod dependency issue.

[swathinsankaran]

When this merge will be released? We are also facing the same issue.

Regards,
Swathin

[rcgoodfellow]

Not releasing this really screws projects that have dependencies with protobufs that have been generated by github.com/golang/protobuf/protoc-gen-go v1.3.5 or later. As the only way to get etcd co-exist with these dependencies is to directly import this commit via

go get go.etcd.io/etcd@221f0cc107cb3497eeb20fb241e1bcafca2e9115

Which then translates into

go.etcd.io/etcd v0.5.0-alpha.5.0.20200306183522-221f0cc107cb

in go.mod parlance.

Given that etcd's go modules are totally broken anyway, we'll likely still have to import commit hashes directly, but at least they'll be pointing at a tagged release that can be matched to etcd server deployment. In the absence of an actual release, every downstream project with recent protoc-gen-go dependencies is relegated to a mishmash of client/server versions that maybe works.

The common workaround noted on this issue and others of replacing grpc's module version with v1.2.6 is not viable for projects that actually depend on generated protobuf code that has elements like grpc.ClientConnInterface that are specific to later versions of protoc-gen-go.

[pipe0482]

Please please please release this fix, our whole team is completely stuck because no builds are working

[gdbelvin]

@mitake @gyuho This issue is holding up a significant portion of the Golang ecosystem updating their dependencies. Please release a version of etcd that contains this commit.

[pipe01]

Workaround: add

replace google.golang.org/grpc => google.golang.org/grpc v1.26.0

to you go.mod file. It's not perfect, but it'll allow you to at least partially update

[AFMiziara]

@rcgoodfellow, did you find any solutions for now? All go clients from googleapis relies on grpc v1.28.0. This simple fix is making impossible to use other packages because of dependencies issues.

[gdbelvin]

@AFMiziara 3.4.8 contains the fix.