Grpc-go: Compile-time assertion : grpc.SupportPackageIsVersion3 and grpc.SupportPackageIsVersion4

[ajayamohan]

Hello,
I have a microservice that uses grpc 1.0 with protobuf 3.0.0 that works just fine in darwin/amd64. If the same steps are carried out to generate *.pb.go files in an alpine container, it results in a compile time assertion.

In the generated code, the difference is as follows:
// This is a compile-time assertion to ensure that this generated file // is compatible with the grpc package it is being compiled against. -const _ = grpc.SupportPackageIsVersion3 +const _ = grpc.SupportPackageIsVersion4

The same build steps are done in darwin as in the alpine build container, which is as follows:

git clone https://github.com/google/protobuf && \
cd protobuf && \
./autogen.sh && \
./configure && \
make && \
make check && \
make install && \
go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway && \
go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger && \
go get -u github.com/golang/protobuf/proto && \
go get -u github.com/golang/protobuf/protoc-gen-go

I'm new to GRPC/HTTP/2, so I could be missing something obvious - If not, has anyone run into this issue?

Thanks,
Ajith

[piotrkowalczuk]

Same problem here. grpc.SupportPackageIsVersion4 breaks public API. It looks like it should be version v4.0.0 but was released as v1.0.4. Otherwise entire versioning is completely useless here.

[menghanl]

This check is to make sure the proto package, the gRPC package and the generated code are in sync.

This should be fixed by

• update the go proto package
  go get -u github.com/golang/protobuf/{proto,protoc-gen-go}.
• update gRPC package
  go get -u google.golang.org/grpc
• rebuild your proto files with protoc --go_out=plugins=grpc:. *.proto.

[iamqizhao]

grpc.SupportPackageIsVersion is used to track the version of the protobuf generated code and is different from the grpc release version. Menghanl made an faq (https://github.com/grpc/grpc-go/pull/970/files) to address this type of questions.

[ajayamohan]

@iamqizhao : go get -u on both grpc and protobuf/{proto, protoc-gen-go} doesn't solve this.

[menghanl]

rebuild your proto files with protoc --go_out=plugins=grpc:. *.proto

What about this?

[ajayamohan]

Yes, the proto files were regenerated. Same failure in building the project after the *.pb.go and *.gw.go files are generated.

// This is a compile-time assertion to ensure that this generated file
// is compatible with the grpc package it is being compiled against.
const _ = grpc.SupportPackageIsVersion4

service.pb.go:333: undefined: grpc.SupportPackageIsVersion4

[menghanl]

This error indicates your gRPC package is not updated.

If you already did go get -u google.golang.org/grpc, you should be able to find this variable in your local grpc package: https://github.com/grpc/grpc-go/blob/master/rpc_util.go#L457.

And if you use go vendor, make sure the vendored grpc is updated.

[matiasinsaurralde]

Thanks, this was useful!

[christianwoehrle]

Thanks, updating the grpc packages worked for me.