问访问node.js中的MySQL或MySQL时，AWS Lambda ETIMEDOUT

EN

function mysqltest2() {
    var mysql      = require('mysql');
    var connection = mysql.createConnection({
      host     : 'endpoint.rds.amazonaws.com',
      user     : 'user',
      password : 'pass',
      database : 'db'
      });
                  var test;
                  console.log(`Intent Request`);
                  console.log('Then run MySQL code:');
                  connection.connect(function(err) {
                      console.log('Inside connection.connect() callback');
                      if (!err) {
                          console.log("Database is connected ... ");
                          connection.query("SELECT 1 + 1 AS solution",
                              function(err, result) {
                                  console.log("Inside connection.query() callback")
                                  if (!err) {
                                      console.log(result);
                                      console.log("Query Successful! Ending Connection.");
                                      test = result;
                                      connection.end();
                            } else {
                                      console.log("Query error!");
                                  }
                              });
                      } else {
                          console.log("Error connecting database ..." +             err.message);
                      }
                  });
                  return test;
  }