[Update] serverless tier example

serverless/Makefile

@@ -0,0 +1,25 @@
+# Copyright 2022 PingCAP, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+.PHONY: all build run
+
+all:
+	make build run
+
+build:
+	go build -o bin/sql-driver-example
+
+run:
+	./bin/sql-driver-example

serverless/go.mod

@@ -0,0 +1,5 @@
+module github.com/pingcap-inc/tidb-example-golang/serverless
+
+go 1.18
+
+require github.com/go-sql-driver/mysql v1.6.0

serverless/go.sum

@@ -0,0 +1,2 @@
+github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
+github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=

serverless/serverless.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"crypto/tls"
+	"database/sql"
+	"fmt"
+	"github.com/go-sql-driver/mysql"
+)
+
+const (
+	tlsConfigKeyName = "tidb"
+	host             = "{serverless tier host}"
+	port             = 4000
+	username         = "{serverless tier username}"
+	password         = "{serverless tier password}"
+)
+
+func main() {
+	mysql.RegisterTLSConfig(tlsConfigKeyName, &tls.Config{
+		MinVersion: tls.VersionTLS12,
+		ServerName: host,
+	})
+
+	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/test?tls=%s",
+		username, password, host, port, tlsConfigKeyName)
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		panic(err)
+	}
+	defer db.Close()
+
+	rows, err := db.Query("SELECT VERSION()")
+	if err != nil {
+		panic(err)
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		version := ""
+		rows.Scan(&version)
+		fmt.Println(version)
+	}
+}