service without gRPC

[Mohamed Koubaa]

Hello,

As per the language guide, defining a service in a .proto file will generate RPC stubs which we can implement (or let gRPC implement). https://developers.google.com/protocol-buffers/docs/proto3#services

We have a zeroMQ service that we are interested in migrating from JSON-RPC to gRPC.  To stage this effort, we are interesting in creating the RPC stubs and using the same zeroMQ to implement them, and then move to gRPC once we deal with an orthogonal service discovery problem that prevents us from dropping zeroMQ immediately.

To my surprise, adding the RPC code to the .proto did not generate any stubs in c++. I am using proto3 beta4 at the moment.  Do I need any additional flags to protoc?

Thanks

Mohamed Koubaa

Software Developer

ANSYS Inc

[Paul Johnston]

You need to invoke the grpc plugin.  The default protoc tool does not generate gRPC stubs on it's own.  Here's what it looks like:

$ protoc --cpp_out=outdir \

  --plugin=protoc-gen-grpc=path/to/the/grpc-cpp-plugin \

  --grpc_out=outdir \

  path/to/your/helloworld.proto

# Generated by protoc

helloworld.pb.h

helloworld.pb.cc

# Generated by grpc plugin

helloworld.grpc.pb.h

helloworld.grpc.pb.cc

I've written a tool for bazel that can do this for you and provide all the required build environment, if you're interested in trying it out.

https://github.com/pubref/rules_protobuf

HTH,

Paul

[John Obaterspok]

Hi,

You could check out https://github.com/thesamet/rpcz

for using protobuf (ver 2) over zeromq. Perhaps that could ease your migration to gRPC.

-- john

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[Mohamed Koubaa]

Thanks for the replies.  The documentation has room for improvement on this.  I just noticed this:

option cc_generic_services = true;

It seems to generate these stubs without the grpc plugin.  However, it did not seem to work for C# or Python (it seems the gRPC plugin is the only way to make those stubs).

I did notice the rpcz project but did not have a chance yet to evaluate it.

Thanks,

Mohamed Koubaa

Software Developer

ANSYS Inc