diff --git a/common/structure/structure.go b/common/structure/structure.go
index 6b038bd2..e74c349a 100644
--- a/common/structure/structure.go
+++ b/common/structure/structure.go
@@ -159,9 +159,19 @@ func (d *Decoder) decodeSlice(name string, data any, val reflect.Value) error {
 		for valSlice.Len() <= i {
 			valSlice = reflect.Append(valSlice, reflect.Zero(valElemType))
 		}
-		currentField := valSlice.Index(i)
-
 		fieldName := fmt.Sprintf("%s[%d]", name, i)
+		if currentData == nil {
+			// in weakly type mode, null will convert to zero value
+			if d.option.WeaklyTypedInput {
+				continue
+			}
+			// in non-weakly type mode, null will convert to nil if element's zero value is nil, otherwise return an error
+			if elemKind := valElemType.Kind(); elemKind == reflect.Map || elemKind == reflect.Slice {
+				continue
+			}
+			return fmt.Errorf("'%s' can not be null", fieldName)
+		}
+		currentField := valSlice.Index(i)
 		if err := d.decode(fieldName, currentData, currentField); err != nil {
 			return err
 		}
diff --git a/log/log.go b/log/log.go
index 58e122ef..f1053f44 100644
--- a/log/log.go
+++ b/log/log.go
@@ -10,8 +10,8 @@ import (
 )
 
 var (
-	logCh  = make(chan *Event)
-	source = observable.NewObservable[*Event](logCh)
+	logCh  = make(chan Event)
+	source = observable.NewObservable[Event](logCh)
 	level  = INFO
 )
 
@@ -57,12 +57,12 @@ func Fatalln(format string, v ...any) {
 	log.Fatalf(format, v...)
 }
 
-func Subscribe() observable.Subscription[*Event] {
+func Subscribe() observable.Subscription[Event] {
 	sub, _ := source.Subscribe()
 	return sub
 }
 
-func UnSubscribe(sub observable.Subscription[*Event]) {
+func UnSubscribe(sub observable.Subscription[Event]) {
 	source.UnSubscribe(sub)
 }
 
@@ -74,7 +74,7 @@ func SetLevel(newLevel LogLevel) {
 	level = newLevel
 }
 
-func print(data *Event) {
+func print(data Event) {
 	if data.LogLevel < level {
 		return
 	}
@@ -91,15 +91,9 @@ func print(data *Event) {
 	}
 }
 
-func newLog(logLevel LogLevel, format string, v ...any) *Event {
-	return &Event{
+func newLog(logLevel LogLevel, format string, v ...any) Event {
+	return Event{
 		LogLevel: logLevel,
 		Payload:  fmt.Sprintf(format, v...),
 	}
 }
-
-func PrintLog(logLevel LogLevel, format string, v ...interface{}) {
-	event := newLog(logLevel, format, v...)
-	logCh <- event
-	print(event)
-}