refactor: error format and function

Author: vczyh

code/code.go

@@ -1,10 +1,10 @@
 package code
 
-type Code uint16
-
 // https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
 // https://dev.mysql.com/doc/refman/8.0/en/error-message-elements.html
 
+type Err uint16
+
 // 1 to 999: Global error codes.
 // This error code range is called “global” because it is a shared range
 // that is used by the server as well as by clients.
@@ -18,9 +18,9 @@ const ()
 
 // 1,000 to 1,999: Server error codes reserved for messages sent to clients.
 const (
-	ErrNo                Code = 1002
-	ErrYes               Code = 1003
-	ErrAccessDeniedError Code = 1045
+	ErrNo                Err = 1002
+	ErrYes               Err = 1003
+	ErrAccessDeniedError Err = 1045
 )
 
 // 2,000 to 2,999: Client error codes reserved for use by the client library.
@@ -37,14 +37,16 @@ const ()
 // zeros to six digits and adding a prefix of MY-.
 const ()
 
-// 50,000 to 51,999: Error codes reserved for use by third parties (not sent to clients).
+// 50,000 to 51,999: Error codes reserved for use by third parties.
 const (
 	// ErrSendToClient reserved for messages sent to clients.
-	ErrSendToClient Code = 50000
+	ErrSendToClient Err = 50000
 
 	// ErrClient reserved only for use by the client library.
-	ErrClient Code = 50600
+	ErrClient Err = 50600
 
 	// ErrServer reserved for messages to be written to the error log (not sent to clients).
-	ErrServer Code = 51200
+	ErrServer Err = 51200
+
+	ErrUndefined Err = 51999
 )

myerrors/error.go

@@ -0,0 +1,118 @@
+package myerrors
+
+import (
+	"fmt"
+	"github.com/vczyh/mysql-protocol/code"
+)
+
+// https://dev.mysql.com/doc/refman/8.0/en/error-message-elements.html
+
+const (
+	ServerName  = "Server"
+	SQLStateDef = "HY000"
+)
+
+type fundamental struct {
+	// name represents server module, only used by server side error message.
+	name     string
+	code     code.Err
+	sqlState string
+	message  string
+}
+
+func New(name string, c code.Err, state, msg string) error {
+	return &fundamental{
+		name:     name,
+		code:     c,
+		sqlState: state,
+		message:  msg,
+	}
+}
+
+func NewServer(c code.Err, msg string) error {
+	return New("Server", c, SQLStateDef, msg)
+}
+
+func NewServerWithSQLState(c code.Err, state, msg string) error {
+	return New("Server", c, state, msg)
+}
+
+func Name(err error) string {
+	if err == nil {
+		return ""
+	}
+	if val, ok := err.(*fundamental); ok {
+		return val.name
+	}
+	return ""
+}
+
+func Code(err error) code.Err {
+	if err == nil {
+		return code.ErrUndefined
+	}
+	if val, ok := err.(*fundamental); ok {
+		return val.code
+	}
+	return code.ErrUndefined
+}
+
+func SQLState(err error) string {
+	if err == nil {
+		return SQLStateDef
+	}
+	if val, ok := err.(*fundamental); ok {
+		return val.sqlState
+	}
+	return SQLStateDef
+}
+
+func Message(err error) string {
+	if err == nil {
+		return ""
+	}
+	if val, ok := err.(*fundamental); ok {
+		return val.message
+	}
+	return ""
+}
+
+func CanSendToClient(err error) bool {
+	if err == nil {
+		return false
+	}
+	if val, ok := err.(*fundamental); ok {
+		c := val.code
+		return c >= 1000 && c <= 1999 || c >= 3000 && c <= 4999 || c >= 5000 && c <= 5999 || c == 50000
+	}
+	return false
+}
+
+func Client(err error) string {
+	if err == nil {
+		return ""
+	}
+	if val, ok := err.(*fundamental); ok {
+		return fmt.Sprintf("ERROR %d (%s): %s", val.code, val.sqlState, val.message)
+	}
+	return ""
+}
+
+func Server(err error) string {
+	if err == nil {
+		return ""
+	}
+	if val, ok := err.(*fundamental); ok {
+		return fmt.Sprintf("[MY-%06d] [%s] %s", val.code, val.name, val.message)
+	}
+	return ""
+}
+
+func (e *fundamental) Error() string {
+	return fmt.Sprintf("%d (%s): %s", e.code, e.sqlState, e.message)
+}
+
+func Is(e error) bool {
+	_, ok := e.(*fundamental)
+	return ok
+}

myerrors/template.go

@@ -0,0 +1,32 @@
+package myerrors
+
+import (
+	"fmt"
+	"github.com/vczyh/mysql-protocol/code"
+)
+
+// https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
+var (
+	AccessDenied = NewTemplate(ServerName, code.ErrAccessDeniedError, "28000", "Access denied for user '%s'@'%s' (using password: %s)")
+)
+
+type template struct {
+	name     string
+	code     code.Err
+	sqlState string
+	format   string
+}
+
+func NewTemplate(name string, c code.Err, state, format string) *template {
+	return &template{
+		name:     name,
+		code:     c,
+		sqlState: state,
+		format:   format,
+	}
+}
+
+func (t *template) Build(args ...interface{}) error {
+	message := fmt.Sprintf(t.format, args...)
+	return New(t.name, t.code, t.sqlState, message)
+}

mysql/conn.go

@@ -5,7 +5,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"github.com/vczyh/mysql-protocol/flag"
-	"github.com/vczyh/mysql-protocol/mysqlerror"
+	"github.com/vczyh/mysql-protocol/myerrors"
 	"github.com/vczyh/mysql-protocol/packet"
 	"net"
 )
@@ -170,17 +170,12 @@ func (c *mysqlConn) WriteEmptyOK() error {
 }
 
 func (c *mysqlConn) WriteError(err error) error {
-	if err == nil {
+	if !myerrors.Is(err) {
 		return nil
 	}
 
-	mysqlErr, ok := err.(mysqlerror.Error)
-	if !ok {
-		return nil
-	}
-
-	if mysqlErr.CanSendToClient() {
-		return c.WritePacket(packet.NewERR(mysqlErr))
+	if myerrors.CanSendToClient(err) {
+		return c.WritePacket(packet.NewERR(err))
 	}
 	return nil
 }

mysqlerror/error.go

@@ -2,7 +2,7 @@ package mysqllog
 
 import (
 	"errors"
-	"github.com/vczyh/mysql-protocol/mysqlerror"
+	"github.com/vczyh/mysql-protocol/myerrors"
 	"io"
 	"log"
 )
@@ -74,8 +74,8 @@ func (l *DefaultLogger) log(lev Level, err error) {
 	if lev < l.lev {
 		return
 	}
-	if mysqlErr, ok := err.(mysqlerror.Error); ok {
-		l.logger.Printf("%s %s\n", lev.String(), mysqlErr.Server())
+	if myerrors.Is(err) {
+		l.logger.Printf("%s %s\n", lev.String(), myerrors.Server(err))
 		return
 	}
 	l.logger.Printf("%s %s", lev.String(), err.Error())