diff --git a/core/codes/codes.go b/core/codes/codes.go
new file mode 100644
index 00000000..9be5bb9c
--- /dev/null
+++ b/core/codes/codes.go
@@ -0,0 +1,11 @@
+package codes
+
+type Code uint32
+
+const (
+	SessionSessionStartError Code = 5001001
+)
+
+var strToCode = map[string]Code{
+	`"SESSION_MODULE_SESSION_START_ERROR"`:   SessionSessionStartError,
+}
diff --git a/core/error/error.go b/core/error/error.go
new file mode 100644
index 00000000..9e257313
--- /dev/null
+++ b/core/error/error.go
@@ -0,0 +1,44 @@
+package error
+
+import "fmt"
+import "github.com/beego/beego/v2/core/codes"
+
+type Code int32
+
+type Error struct {
+    Code Code
+    Msg string
+}
+
+// New returns a Error representing c and msg.
+func New(c Code, msg string) *Error {
+    return &Error{Code: c, Msg: msg}
+}
+
+// Err returns an error representing c and msg.  If c is OK, returns nil.
+func Err(c codes.Code, msg string) error {
+	return New(c, msg)
+}
+
+// Errorf returns Error(c, fmt.Sprintf(format, a...)).
+func Errorf(c codes.Code, format string, a ...interface{}) error {
+	return Err(c, fmt.Sprintf(format, a...))
+}
+
+func (e *Error) Error() string {
+	return fmt.Sprintf("beego error: code = %s desc = %s", e.GetCode(), e.GetMessage())
+}
+
+func (x *Error) GetCode() Code {
+	if x != nil {
+		return x.Code
+	}
+	return 0
+}
+
+func (x *Error) GetMessage() string {
+	if x != nil {
+		return x.Msg
+	}
+	return ""
+}
\ No newline at end of file