For this sample, we've already generated the server and client stubs from helloworld.proto.
$ go help gopath $ # ensure the PATH contains $GOPATH/bin $ export PATH=$PATH:$GOPATH/bin
$ go get -u google.golang.org/grpc/examples/helloworld/greeter_client $ go get -u google.golang.org/grpc/examples/helloworld/greeter_server
$ greeter_server &
$ greeter_client
1 First install protoc
2 Install the protoc Go plugin.
$ go get -a github.com/golang/protobuf/protoc-gen-go $ $ # from this dir; invoke protoc $ protoc -I ./helloworld/helloworld/ ./helloworld/helloworld/helloworld.proto --go_out=plugins=grpc:helloworld