do

.gitignore

@@ -0,0 +1,2 @@
+.idea
+go2proto

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Andžej Maciusovič
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,9 @@
+# go2proto
+
+Generate protobuf messages from given go structs.
+
+### Example
+
+git clone github.com/anjmao/go2proto
+cd go2proto
+go run main.go -f /YourPWD/example/out -p github.com/anjmao/go2proto/example/in

example/in/model.go

@@ -0,0 +1,45 @@
+package in
+
+type EventSubForm struct {
+	Id string
+
+	Caption string
+
+	Rank int32
+
+	Fields *ArrayOfEventField
+}
+
+type ArrayOfEventField struct {
+	EventField []*EventField
+}
+
+type EventField struct {
+	Id string
+
+	Name string
+
+	FieldType string
+
+	IsMandatory bool
+
+	Rank int32
+
+	Tag string
+
+	Items *ArrayOfEventFieldItem
+
+	CustomFieldOrder int32
+}
+
+type ArrayOfEventFieldItem struct {
+	EventFieldItem []*EventFieldItem
+}
+
+type EventFieldItem struct {
+	Id string
+
+	Text string
+
+	Rank int32
+}

example/out/output.proto

@@ -0,0 +1,36 @@
+syntax = "proto3";
+package proto;
+
+
+message ArrayOfEventFieldItem { 
+  repeated EventFieldItem eventFieldItem = 1;
+}
+
+message EventSubForm {
+  string id = 1;
+  string caption = 2;
+  int32 rank = 3;
+  ArrayOfEventField fields = 4;
+}
+
+message EventField {
+  string id = 1;
+  string name = 2;
+  string fieldType = 3;
+  bool isMandatory = 4;
+  int32 rank = 5;
+  string tag = 6;
+  ArrayOfEventFieldItem items = 7;
+  int32 customFieldOrder = 8;
+}
+
+message ArrayOfEventField { 
+  repeated EventField eventField = 1;
+}
+
+message EventFieldItem {
+  string id = 1;
+  string text = 2;
+  int32 rank = 3;
+}
+

go.mod

@@ -0,0 +1,5 @@
+module github.com/anjmao/go2proto
+
+go 1.12
+
+require golang.org/x/tools v0.0.0-20190319232107-3f1ed9edd1b4

go.sum

@@ -0,0 +1,6 @@
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20190319232107-3f1ed9edd1b4 h1:4oAPsdy/MJIeaCzEMEhYwYBU/gHkXH52Xa4M+0GBHfA=
+golang.org/x/tools v0.0.0-20190319232107-3f1ed9edd1b4/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=

main.go

@@ -0,0 +1,180 @@
+package main
+
+import (
+	"flag"
+	"go/token"
+	"go/types"
+	"golang.org/x/tools/go/packages"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+	"unicode"
+	"unicode/utf8"
+)
+
+type arrFlags []string
+
+func (i *arrFlags) String() string {
+	return ""
+}
+
+func (i *arrFlags) Set(value string) error {
+	*i = append(*i, value)
+	return nil
+}
+
+var (
+	protoFolder = flag.String("f", "", "Proto output path.")
+	pkgFlags    arrFlags
+)
+
+func main() {
+	flag.Var(&pkgFlags, "p", "Go source packages.")
+	flag.Parse()
+
+	if len(pkgFlags) == 0 || protoFolder == nil {
+		flag.PrintDefaults()
+		os.Exit(1)
+	}
+
+	if err := checkOutFolder(*protoFolder); err != nil {
+		log.Fatal(err)
+	}
+
+	pwd, err := os.Getwd()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	pkgs, err := loadPackages(pwd, pkgFlags)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	msgs := getMessages(pkgs)
+
+	if err := writeOutput(msgs, *protoFolder); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func checkOutFolder(path string) error {
+	_, err := os.Stat(path)
+	return err
+}
+
+func loadPackages(pwd string, pkgs []string) ([]*packages.Package, error) {
+	fset := token.NewFileSet()
+	cfg := &packages.Config{
+		Dir:  pwd,
+		Mode: packages.LoadSyntax,
+		Fset: fset,
+	}
+	return packages.Load(cfg, pkgs...)
+}
+
+type message struct {
+	Name   string
+	Fields []*field
+}
+
+type field struct {
+	Name       string
+	TypeName   string
+	Order      int
+	IsRepeated bool
+}
+
+func getMessages(pkgs []*packages.Package) []*message {
+	out := []*message{}
+	for _, p := range pkgs {
+		for _, t := range p.TypesInfo.Defs {
+			if t == nil {
+				continue
+			}
+			if !t.Exported() {
+				continue
+			}
+			if s, ok := t.Type().Underlying().(*types.Struct); ok {
+				out = appendMessage(out, t, s)
+			}
+		}
+
+	}
+	return out
+}
+
+func appendMessage(out []*message, t types.Object, s *types.Struct) []*message {
+	msg := &message{
+		Name:   t.Name(),
+		Fields: []*field{},
+	}
+
+	for i := 0; i < s.NumFields(); i++ {
+		f := s.Field(i)
+		if !f.Exported() {
+			continue
+		}
+		newField := &field{
+			Name:       toProtoFieldName(f.Name()),
+			TypeName:   toProtoFieldTypeName(f),
+			IsRepeated: isRepeated(f),
+			Order:      i + 1,
+		}
+		msg.Fields = append(msg.Fields, newField)
+	}
+	out = append(out, msg)
+	return out
+}
+
+func toProtoFieldTypeName(f *types.Var) string {
+	switch f.Type().Underlying().(type) {
+	case *types.Basic:
+		return f.Type().String()
+	case *types.Slice, *types.Pointer:
+		parts := strings.Split(f.Type().String(), ".")
+		return parts[len(parts)-1]
+	}
+	return f.Type().String()
+}
+
+func isRepeated(f *types.Var) bool {
+	_, ok := f.Type().Underlying().(*types.Slice)
+	return ok
+}
+
+func toProtoFieldName(name string) string {
+	r, n := utf8.DecodeRuneInString(name)
+	return string(unicode.ToLower(r)) + name[n:]
+}
+
+func writeOutput(msgs []*message, path string) error {
+	msgTemplate := `syntax = "proto3";
+package proto;
+
+{{range .}}
+message {{.Name}} {
+{{- range .Fields}}
+{{- if .IsRepeated}} 
+  repeated {{.TypeName}} {{.Name}} = {{.Order}};
+{{- else}}
+  {{.TypeName}} {{.Name}} = {{.Order}};
+{{- end}}
+{{- end}}
+}
+{{end}}
+`
+	tmpl, err := template.New("test").Parse(msgTemplate)
+	if err != nil {
+		panic(err)
+	}
+
+	f, err := os.Create(filepath.Join(path, "output.proto"))
+	if err != nil {
+		return err
+	}
+
+	return tmpl.Execute(f, msgs)
+}