package main import ( "database/sql" "log" "os" ) var db *sql.DB func init() { dataSourceName := os.Getenv("MYSQL_DATA_SOURCE_NAME") d, err := sql.Open("mysql", dataSourceName) if err != nil { log.Panic(err) } err = d.Ping() if err != nil { log.Panic(err) } db = d } func createClient(dataSourceName string) (*sql.DB, error) { db, err := sql.Open("mysql", dataSourceName) if err != nil { return nil, err } if err = db.Ping(); err != nil { return nil, err } return db, nil }