From c422dd11b87bf2cc78db4a1747afd0aeee68f657 Mon Sep 17 00:00:00 2001
From: Jason <oblitorum@gmail.com>
Date: Tue, 31 Oct 2023 03:41:15 +0800
Subject: [PATCH] Add default connection attribute '_server_host'

---
 connector.go | 9 ++++++---
 const.go     | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/connector.go b/connector.go
index c4ea5bc25..6e8d65f6d 100644
--- a/connector.go
+++ b/connector.go
@@ -22,7 +22,7 @@ type connector struct {
 	encodedAttributes string  // Encoded connection attributes.
 }
 
-func encodeConnectionAttributes(textAttributes string) string {
+func encodeConnectionAttributes(cfg *Config) string {
 	connAttrsBuf := make([]byte, 0)
 
 	// default connection attributes
@@ -34,9 +34,12 @@ func encodeConnectionAttributes(textAttributes string) string {
 	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrPlatformValue)
 	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrPid)
 	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, strconv.Itoa(os.Getpid()))
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrServerHost)
+	serverHost, _, _ := net.SplitHostPort(cfg.Addr)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, serverHost)
 
 	// user-defined connection attributes
-	for _, connAttr := range strings.Split(textAttributes, ",") {
+	for _, connAttr := range strings.Split(cfg.ConnectionAttributes, ",") {
 		k, v, found := strings.Cut(connAttr, ":")
 		if !found {
 			continue
@@ -49,7 +52,7 @@ func encodeConnectionAttributes(textAttributes string) string {
 }
 
 func newConnector(cfg *Config) *connector {
-	encodedAttributes := encodeConnectionAttributes(cfg.ConnectionAttributes)
+	encodedAttributes := encodeConnectionAttributes(cfg)
 	return &connector{
 		cfg:               cfg,
 		encodedAttributes: encodedAttributes,
diff --git a/const.go b/const.go
index 0f2621a6f..22526e031 100644
--- a/const.go
+++ b/const.go
@@ -26,6 +26,7 @@ const (
 	connAttrPlatform        = "_platform"
 	connAttrPlatformValue   = runtime.GOARCH
 	connAttrPid             = "_pid"
+	connAttrServerHost      = "_server_host"
 )
 
 // MySQL constants documentation: