complete struct tag plugin

Author: theluckiestsoul

Makefile

@@ -0,0 +1,3 @@
+install:
+	cd cmd/protoc-gen-structtag && go install && cd ..
+.PHONY: install

cmd/protoc-gen-structtag/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"errors"
+	"flag"
+
+	"google.golang.org/protobuf/compiler/protogen"
+)
+
+var dbtag *string
+
+func main() {
+	var flags flag.FlagSet
+	dbtag = flags.String("dbtag", "", "db tag to use for generated structs")
+
+	options := protogen.Options{
+		ParamFunc: flags.Set,
+	}
+	options.Run(func(gen *protogen.Plugin) error {
+		if *dbtag == "" {
+			gen.Error(errors.New("dbtag must be set"))
+		}
+		for _, f := range gen.Files {
+			if !f.Generate {
+				continue
+			}
+			generateStructTags(gen, f)
+
+		}
+		return nil
+	})
+}
+
+func generateStructTags(gen *protogen.Plugin, file *protogen.File) *protogen.GeneratedFile {
+	filename := file.GeneratedFilenamePrefix + "_structtags.pb.go"
+	g := gen.NewGeneratedFile(filename, file.GoImportPath)
+	g.P("// Code generated by protoc-gen-go-structtags. DO NOT EDIT.")
+	g.P()
+	g.P("package ", file.GoPackageName)
+	g.P()
+	for _, message := range file.Messages {
+		g.P("type ", message.GoIdent, " struct {")
+		for _, field := range message.Fields {
+			g.P(field.GoName, " ", field.Desc.Kind(), " `json:\"", field.Desc.Name(), "\" ", *dbtag, ":\"", field.Desc.Name(), "\"`")
+		}
+		g.P("}")
+	}
+
+	return g
+}

example/Makefile

@@ -0,0 +1,4 @@
+generate:
+	protoc --go_out=pkg --go_opt=paths=source_relative --proto_path=proto \
+    --structtag_out=internal --structtag_opt=paths=source_relative,dbtag=bun \
+    proto/*.proto

example/go.mod

@@ -0,0 +1,3 @@
+module github.com/theluckiestsoul/protoc-gen-structtag/example
+
+go 1.21.0