package main import ( "bytes" "fmt" "google.golang.org/protobuf/compiler/protogen" ) func (g *Generator) openapiGenerate(component string, plugin *protogen.Plugin) error { for _, file := range plugin.Files { if !file.Generate { continue } // 1. Initialise a buffer to hold the generated code var buf bytes.Buffer // 2. Write the package name pkg := fmt.Sprintf("package %s", file.GoPackageName) buf.Write([]byte(pkg)) // 3. For each message add our Foo() method for _, msg := range file.Proto.MessageType { buf.Write([]byte(fmt.Sprintf(`func (x %s) Foo() string { return "bar"}`, *msg.Name))) } // 4. Specify the output filename, in this case test.foo.go filename := file.GeneratedFilenamePrefix + ".foo.go" file := plugin.NewGeneratedFile(filename, ".") // 5. Pass the data from our buffer to the plugin file struct file.Write(buf.Bytes()) } return nil }