Use functional options

gorm.go

@@ -56,6 +56,26 @@ type Config struct {
 	cacheStore *sync.Map
 }
 
+func (c *Config) Apply(config *Config) error {
+	return nil
+}
+
+func (c *Config) AfterInitialize(db *DB) error {
+	if db != nil {
+		for _, plugin := range c.Plugins {
+			if err := plugin.Initialize(db); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+type Option interface {
+	Apply(*Config) error
+	AfterInitialize(*DB) error
+}
+
 // DB GORM DB definition
 type DB struct {
 	*Config
@@ -83,9 +103,16 @@ type Session struct {
 }
 
 // Open initialize db session based on dialector
-func Open(dialector Dialector, config *Config) (db *DB, err error) {
-	if config == nil {
-		config = &Config{}
+func Open(dialector Dialector, opts ...Option) (db *DB, err error) {
+	config := &Config{}
+
+	for _, opt := range opts {
+		if opt != nil {
+			if err := opt.Apply(config); err != nil {
+				return nil, err
+			}
+			defer opt.AfterInitialize(db)
+		}
 	}
 
 	if config.NamingStrategy == nil {
@@ -106,14 +133,6 @@ func Open(dialector Dialector, config *Config) (db *DB, err error) {
 
 	if config.Plugins == nil {
 		config.Plugins = map[string]Plugin{}
-	} else {
-		for _, p := range config.Plugins {
-			defer func(plugin Plugin) {
-				if errr := plugin.Initialize(db); errr != nil {
-					err = errr
-				}
-			}(p)
-		}
 	}
 
 	if config.cacheStore == nil {