plugins are not supported : grpc

[harrybin815]

run:

protoc protoc/route_guide.proto --go_out=plugins=grpc:.

output:

--go_out: protoc-gen-go: plugins are not supported; use 'protoc --go-grpc_out=...' to generate gRPC

[neild]

The google.golang.org/protobuf/cmd/protoc-gen-go program doesn't include gRPC support. Instead, that support will soon be provided by a google.golang.org/grpc/cmd/protoc-gen-go-grpc program. That program is In code review now, but not quite yet available.

The github.com/golang/protobuf/protoc-gen-go program supports gRPC as always, and will continue to do so. Versions v1.4 and newer of that program support the new protobuf reflection features. (Right now, the newest release is v1.4.0-rc.4.)

[alexshtin]

@neild, thanks for update. Could you provide very approximate date for gRPC support in google.golang.org/protobuf/cmd/protoc-gen-go?

[neild]

google.golang.org/protobuf/cmd/protoc-gen-go will never have explicit gRPC support. We've split it out into a separate program (protoc-gen-go-grpc), so the gRPC code generator can live in the gRPC repository and follow that repo's release cycle.

The practical effect is that when using this generator you will need to specify two flags on the protoc command line (or run protoc twice):

protoc --go_out=. --go-grpc_out=. foo.proto

The original github.com/golang/protobuf/protoc-gen-go will continue to directly support gRPC generation indefinitely, to avoid breaking existing users.

[alexshtin]

Ok, this is better approach, I agree. I will rephrase my question though: could you provide very approximate date when google.golang.org/protobuf/cmd/protoc-gen-go-grpc is available?

[neild]

Whenever grpc/grpc-go#3453 is approved and merged; unfortunately, the timing of that isn't under my control, so I can't give even an approximate date. It's in the gRPC folks' hands right now, but current events have everyone working at reduced capacity and I don't know where this is on their priority list.

[alexshtin]

Thanks @neild. I am super excited about V2. Great job!

[dsnet]

I'm going to close this issue, since it seems to be a duplicate of #903

[kraymond37]

This doc needs to be updated.

[dsnet]

I recommend filing an issue on https://github.com/grpc/grpc-go/issues

[quinn]

It seems strange to give a warning and recommend using a plugin that does not yet exist.

[shanduur]

How to use original github.com/golang/protobuf/protoc-gen-go? The new way just broke all my codebase...

[AndresHMosqueda]

How can I fix this issue?

--go_out: protoc-gen-go: plugins are not supported; use 'protoc --go-grpc_out=...' to generate gRPC

[shanduur]

@AndresHMosqueda this should work:
protoc --proto_path=proto --go_out=plugins=grpc:. proto/*.proto

[puellanivis]

gRPC generation is no longer handled as a plugin of this protoc-gen-go package. We only generate the protobuf definitions, the protoc-gen-go-grpc is now responsible for generating grpc code.

It tells you what you need to do:

protoc --go-grpc_out=. dummy/dummyProt/dummy.proto

[CrayfishGo]

google.golang.org/protobuf/cmd/protoc-gen-go will never have explicit gRPC support. We've split it out into a separate program (protoc-gen-go-grpc), so the gRPC code generator can live in the gRPC repository and follow that repo's release cycle.

The practical effect is that when using this generator you will need to specify two flags on the protoc command line (or run protoc twice):

protoc --go_out=. --go-grpc_out=. foo.proto

The original github.com/golang/protobuf/protoc-gen-go will continue to directly support gRPC generation indefinitely, to avoid breaking existing users.

This can work. Great

[tejasjadhav]

How do I use custom plugins with this change? We used to rely on that to generate custom gRPC implementation and a few additional code using our own custom plugins.

Also, why was this change introduced as a minor version change when it is breaking backward compatibility?

[neild]

why was this change introduced as a minor version change

It was not.

google.golang.org/protobuf/cmd/protoc-gen-go has never supported gRPC code generation.

github.com/golang/protobuf/cmd/protoc-gen-go still contains gRPC code generation support. (However, the gRPC code generation is frozen and superseded by google.golang.org/grpc/cmd/protoc-gen-go-grpc, so I would recommend switching to the gRPC-owned plugin at your earliest convenience.)

[tejasjadhav]

@neild reason for stating this as as a minor version change is that in v1.3.5 we could still specify custom plugins (ex. plugins=grpc+my-custom-plugin). In v1.4.0 that support was removed.

This did break our internal code generation scripts as they relied on the plugins parameter. For now the workaround that we going ahead with is to generate the gRPC clients based on v1.3.5 and generate the gRPC server as per the latest version.

[neild]

There has never been a way to add a custom plugin to protoc-gen-go, however. The list of plugins is built in at compile time. You can build your own generator binary uses the github.com/golang/protobuf/protoc-gen-go/generator package and adds a plugin, but that is still possible with v1.4.0. (New code should use the protogen package, however.)

The removed support you link to is in an executable (package main), not an importable package.