go1.25 bumped lib version added in dotenv assign func

dotenv/assign.go

@@ -0,0 +1,82 @@
+package dotenv
+
+import (
+	"errors"
+	"log/slog"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+// Assign env tag matching values from envMap
+func Assign[T any](c *T, envMap map[string]string) error {
+	if c == nil {
+		return errors.New("nil arg")
+	}
+
+	slog.Info("env map", "v", envMap)
+
+	val := reflect.Indirect(reflect.ValueOf(c))
+	name := val.Type().Name()
+	for i := range val.NumField() {
+		f := val.Type().Field(i)
+		tag := f.Tag.Get("env")
+		if tag == "" {
+			continue
+		}
+
+		var v string
+		var ok bool
+		if multiTag := strings.Split(tag, ","); len(multiTag) > 1 {
+			// multi tags like env:"DB_URL,PG_DB_URL"
+			for _, mt := range multiTag {
+				if v, ok = envMap[strings.TrimSpace(mt)]; ok {
+					break
+				}
+			}
+		} else {
+			v, ok = envMap[tag]
+		}
+
+		if !ok {
+			continue
+		}
+
+		field := val.FieldByName(f.Name)
+		if !field.IsValid() {
+			continue
+		}
+
+		switch f.Type.Kind() {
+		case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int:
+			if v, err := strconv.ParseInt(v, 10, 64); err != nil {
+				return err
+			} else {
+				field.SetInt(v)
+			}
+		case reflect.Float32, reflect.Float64:
+			if v, err := strconv.ParseFloat(v, 10); err != nil {
+				return err
+			} else {
+				field.SetFloat(v)
+			}
+		case reflect.Bool:
+			if strings.EqualFold(v, "true") {
+				field.SetBool(true)
+			} else {
+				field.SetBool(false)
+			}
+
+		default:
+			field.SetString(v)
+		}
+
+		if name == "" {
+			slog.Info("override value from env", "field", f.Name)
+		} else {
+			slog.Info("override value from env", "type", name, "field", f.Name)
+		}
+	}
+
+	return nil
+}