feat(goctl): Support gateway sample generation (#3049)

tools/goctl/internal/flags/flags.go

@@ -0,0 +1,101 @@
+package flags
+
+import (
+	"bytes"
+	_ "embed"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"strings"
+	"testing"
+
+	"github.com/zeromicro/go-zero/tools/goctl/util"
+)
+
+//go:embed default_en.json
+var defaultEnFlagConfig []byte
+
+type ConfigLoader struct {
+	conf map[string]any
+}
+
+func (cl *ConfigLoader) ReadConfig(in io.Reader) error {
+	return json.NewDecoder(in).Decode(&cl.conf)
+}
+
+func (cl *ConfigLoader) GetString(key string) string {
+	keyList := strings.FieldsFunc(key, func(r rune) bool {
+		return r == '.'
+	})
+	var conf = cl.conf
+	for idx, k := range keyList {
+		val, ok := conf[k]
+		if !ok {
+			return ""
+		}
+		if idx < len(keyList)-1 {
+			conf, ok = val.(map[string]any)
+			if !ok {
+				return ""
+			}
+			continue
+		}
+
+		return fmt.Sprint(val)
+	}
+	return ""
+}
+
+type Flags struct {
+	loader *ConfigLoader
+}
+
+func MustLoad() *Flags {
+	loader := &ConfigLoader{
+		conf: map[string]any{},
+	}
+	if err := loader.ReadConfig(bytes.NewBuffer(defaultEnFlagConfig)); err != nil {
+		log.Fatal(err)
+	}
+
+	return &Flags{
+		loader: loader,
+	}
+}
+
+func setTestData(t *testing.T, data []byte) {
+	origin := defaultEnFlagConfig
+	defaultEnFlagConfig = data
+	t.Cleanup(func() {
+		defaultEnFlagConfig = origin
+	})
+}
+
+func (f *Flags) Get(key string) (string, error) {
+	value := f.loader.GetString(key)
+	for util.IsTemplateVariable(value) {
+		value = util.TemplateVariable(value)
+		if value == key {
+			return "", fmt.Errorf("the variable can not be self: %q", key)
+		}
+		return f.Get(value)
+	}
+	return value, nil
+}
+
+var flags *Flags
+
+func Get(key string) string {
+	if flags == nil {
+		flags = MustLoad()
+	}
+
+	v, err := flags.Get(key)
+	if err != nil {
+		log.Fatal(err)
+		return ""
+	}
+
+	return v
+}