protoc not generating service stub files

Question

I have just started playing with google proto. When I try to compile proto file present in proto-java example, it does not generate any grpc file.

proto file, https://github.com/grpc/grpc-java/blob/master/examples/src/main/proto/hello_world.proto

terminal output,

rsonkhla@raman-OptiPlex-9020:~/sandbox/grpc-java/examples$ protoc --version libprotoc 3.0.0 rsonkhla@raman-OptiPlex-9020:~/sandbox/grpc-java/examples$ protoc --java_out=test/ -I../../grpc-java/examples ../../grpc-java/examples/src/main/proto/hello_world.proto rsonkhla@raman-OptiPlex-9020:~/sandbox/grpc-java/examples$ ls -R test/ test/: io

test/io: grpc

test/io/grpc: examples

test/io/grpc/examples: helloworld

test/io/grpc/examples/helloworld: HelloRequest.java
HelloResponse.java HelloWorldProto.java HelloRequestOrBuilder.java HelloResponseOrBuilder.java

Has anybody else faced this issue?

Answer 1

The command line you are showing does not enable the grpc plugin. You need to specify an _out argument for the grpc plugin, which enables the plugin and specifies where it should output files. Since the plugin is likely not in your PATH, you also need to tell protoc how to find the plugin with --plugin.

So you need to add two arguments:

--plugin=protoc-gen-grpc-java=path/to/protoc-gen-grpc-java --grpc-java_out=path/to/output/dir

For more info, see the gRPC compiler documentation.

Answer 2

You can add these option to your .proto (base on your language) to generate abstract services:

option cc_generic_services = true;
option java_generic_services = true;
option py_generic_services = true;

You can also add --plugin=EXECUTABLE option in your protoc cmd to use custom code generator plugin to generate code more specific to each system, rather than rely on the "abstract" services. Just like Eric's suggestion.