Skipping files without messages

.gitignore

@@ -0,0 +1 @@
+build

Makefile

@@ -1,3 +1,6 @@
 .PHONY: proto
 proto:
-	cd e2e && protoc --go_out=. --go-json_out=logtostderr=true:. e2e.proto
+	mkdir -p build
+	go build -o build/protoc-gen-go-json .
+	export PATH=$(CURDIR)/build/:$$PATH && \
+	    cd e2e && protoc --go_out=. --go-json_out=logtostderr=true,v=10:. *.proto

e2e/e2e_service.proto

@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+package e2e;
+
+import "e2e.proto";
+
+service E2E {
+  rpc Hello(Basic) returns (Basic) {}
+}

gen/generator.go

@@ -36,6 +36,11 @@ func New(reg *descriptor.Registry, opts Options) *generator {
 func (g *generator) Generate(targets []*descriptor.File) ([]*plugin.CodeGeneratorResponse_File, error) {
 	var files []*plugin.CodeGeneratorResponse_File
 	for _, file := range targets {
+		if len(file.Messages) == 0 {
+			glog.V(1).Infof("Skipping %s, no messages", file.GetName())
+			continue
+		}
+
 		glog.V(1).Infof("Processing %s", file.GetName())
 		code, err := g.generate(file)
 		if err != nil {