clientv3: grpc-go (v1.27.0) made API changes to balancer / resolver.

[eddycjy]

After the release of grpc-go v1.27.0, an error occurred while pulling etcd / clientv3. The steps to reproduce it are as follows:

1. go.mod:

go 1.13

require (
	github.com/coreos/etcd v3.3.18+incompatible // indirect
	github.com/coreos/go-systemd v0.0.0-00010101000000-000000000000 // indirect
	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect
	github.com/gogo/protobuf v1.3.1 // indirect
	github.com/google/uuid v1.1.1 // indirect
	go.etcd.io/etcd v3.3.18+incompatible // indirect
	go.uber.org/zap v1.13.0 // indirect
	google.golang.org/grpc v1.27.0 // indirect
)

replace github.com/coreos/go-systemd => github.com/coreos/go-systemd/v22 v22.0.0

2. command:

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

3. PR：clientv3: Fix grpc-go(v1.27.0) incompatible changes to balancer/resolver. #11564

[xiang90]

/cc @jpbetz

[nieaowei]

版本不兼容，指定grpc的版本为1.26即可解决问题。
google.golang.org/grpc v1.26.0

[eddycjy]

@nieaowei Yes, but we need to solve the problem fundamentally.

[g00nix]

Did you find any workaround?

[eddycjy]

@gun1x You can first downgrade grpc to v1.26.0 to temporarily avoid this problem.

[g00nix]

@gun1x You can first downgrade grpc to v1.26.0 to temporarily avoid this problem.

ok, so the actual fix is adding this to go.mod:

require google.golang.org/grpc v1.26.0
replace github.com/coreos/go-systemd => github.com/coreos/go-systemd/v22 v22.0.0

[tstratton-ut]

@gun1x can i see your full go.mod for that fix? your suggestion does not fix the issue for me and i'm wondering if i'm missing something.

replace github.com/coreos/go-systemd => github.com/coreos/go-systemd/v22 v22.0.0

require (
	github.com/coreos/etcd v3.3.18+incompatible // indirect
	github.com/go-log/log v0.2.0 // indirect
	github.com/gogo/protobuf v1.3.1 // indirect
	github.com/json-iterator/go v1.1.9 // indirect
	github.com/lucas-clemente/quic-go v0.14.3 // indirect
	github.com/marten-seemann/qtls v0.7.1 // indirect
	github.com/micro/go-micro v1.18.0
	github.com/miekg/dns v1.1.27 // indirect
	github.com/mostfamiliar/shippy-service-consignment v0.0.0-20200212041600-94c659f72b79
	github.com/nats-io/jwt v0.3.2 // indirect
	github.com/pkg/errors v0.9.1 // indirect
	go.uber.org/atomic v1.5.1 // indirect
	go.uber.org/multierr v1.4.0 // indirect
	go.uber.org/zap v1.13.0 // indirect
	golang.org/x/crypto v0.0.0-20200210222208-86ce3cb69678 // indirect
	golang.org/x/lint v0.0.0-20200130185559-910be7a94367 // indirect
	golang.org/x/tools v0.0.0-20200211205636-11eff242d136 // indirect
	google.golang.org/genproto v0.0.0-20200211111953-2dc5924e3898 // indirect
	google.golang.org/grpc v1.27.1
)

error:

../../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

[eddycjy]

@mostfamiliar Your google.golang.org/grpc v1.27.1 should be modified to google.golang.org/grpc v1.26.0.

[g00nix]

@gun1x can i see your full go.mod for that fix? your suggestion does not fix the issue for me and i'm wondering if i'm missing something.

module mymod

go 1.13

require (
	github.com/coreos/etcd v3.3.18+incompatible
	github.com/coreos/go-systemd v0.0.0-00010101000000-000000000000 // indirect
	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect
	github.com/gogo/protobuf v1.3.1 // indirect
	github.com/google/uuid v1.1.1 // indirect
	go.uber.org/zap v1.13.0 // indirect
	google.golang.org/grpc v1.26.0
)

replace github.com/coreos/go-systemd => github.com/coreos/go-systemd/v22 v22.0.0