From 88dfb5d41cd36f6560f1ab9b20343e2c3a87ab8a Mon Sep 17 00:00:00 2001
From: Prasad Ghangal <prasad.ghangal@gmail.com>
Date: Fri, 19 Jul 2019 17:27:30 +0530
Subject: [PATCH] yaml2go: convert yamls to go structs

---
 main.go | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 main.go

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..226c521
--- /dev/null
+++ b/main.go
@@ -0,0 +1,120 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"go/format"
+	"gopkg.in/yaml.v2"
+//	"io/ioutil"
+	"log"
+	"os"
+	"reflect"
+	"strings"
+)
+
+type Yaml2Go struct {
+	Result string
+}
+
+func (yg *Yaml2Go) AppendResult(line string) {
+	yg.Result += line
+}
+
+func main() {
+	// Read input from the console
+	var data string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		data += scanner.Text() + "\n"
+	}
+	if err := scanner.Err(); err != nil {
+	   log.Fatal("Error while reading input:", err)
+	}
+
+	// Unmarshal to map[string]interface{}
+	var t map[string]interface{}
+	err := yaml.Unmarshal([]byte(data), &t)
+	if err != nil {
+		log.Fatal("Failed to parse input")
+	}
+
+	y2g := Yaml2Go{}
+	y2g.AppendResult("type Yaml2Go struct {\n")
+	y2g.Convert(t)
+	y2g.AppendResult("}")
+
+	// Convert result into go format
+	goFormat, err := format.Source([]byte(y2g.Result))
+	if err != nil {
+		log.Fatal("go fmt error:", err)
+	}
+	fmt.Printf(string(goFormat))
+	return
+}
+
+// removeUnderscores and camelize string
+func goKeyFormat(key string) string {
+	var st string
+	strList := strings.Split(key, "_")
+	for _, str := range(strList) {
+		st += strings.Title(str)
+	}
+	if len(st) == 0 {
+		st = key
+	}
+	return st
+}
+
+// Convert transforms map[string]interfaceP{} to go struct
+func (yg *Yaml2Go) Convert(obj map[string]interface{}) {
+	for k, v := range obj {
+		yg.Structify(k, v, false)
+	}
+}
+
+// Structify transforms map key values to struct fields
+func (yg *Yaml2Go) Structify(k string, v interface{}, arrayElem bool) {
+	if reflect.TypeOf(v) == nil {
+		yg.AppendResult(fmt.Sprintf("%s interface{} `yaml:\"%s\"`\n", goKeyFormat(k), k))
+		return
+	}
+
+	switch reflect.TypeOf(v).Kind() {
+	case reflect.Map:
+		switch val := v.(type) {
+		case map[interface{}]interface{}:
+			if !arrayElem {
+				yg.AppendResult(fmt.Sprintf("%s struct { \n", goKeyFormat(k)))
+			}
+			for k1, v1 := range val {
+				if _, ok := k1.(string); ok {
+					yg.Structify(k1.(string), v1, false)
+				}
+			}
+			if !arrayElem {
+				yg.AppendResult(fmt.Sprintf("} `yaml:\"%s\"`\n", k))
+			}
+		}
+
+	case reflect.Slice:
+		val := v.([]interface{})
+		if len(val) != 0 {
+			return
+		}
+		switch val[0].(type) {
+
+		case string, int, bool:
+			yg.AppendResult(fmt.Sprintf("%s []%s `yaml:\"%s\"`\n", goKeyFormat(k), reflect.TypeOf(val[0]), k))
+
+		case map[interface{}]interface{}:
+			yg.AppendResult(fmt.Sprintf("%s []struct { \n", goKeyFormat(k)))
+			for _, v1 := range val {
+				yg.Structify(goKeyFormat(k), v1, true)
+			}
+			yg.AppendResult(fmt.Sprintf("} `yaml:\"%s\"`\n", k))
+		}
+
+	default:
+		yg.AppendResult(fmt.Sprintf("%s %s `yaml:\"%s\"`\n", goKeyFormat(k), reflect.TypeOf(v).String(), k))
+	}
+}