将 Lambda function 连接到 AWS 上的 RDS

Question

I'm trying to connect to a msql database on AWS using the following lambda function

const dotenv = require('dotenv');
dotenv.config();

var mysql = require('mysql');


var pool  = mysql.createPool({
    host     : process.env.DBHOST,
    user     : process.env.DBUSER,
    password : process.env.DBPASSWORD,
    database : process.env.DBNAME
  });

exports.handler =  (event, context, callback) => {
  //prevent timeout from waiting event loop
  context.callbackWaitsForEmptyEventLoop = false;
  pool.getConnection(function(err, connection) {
    // Use the connection
    connection.query('select * from products', function (error, results, fields) {
      // And done with the connection.
      connection.release();
      // Handle error after the release.
      if (error) callback(error);
      else callback(null,results[0].emp_name);

    });
  });
};

When executed it gives the following error:

Response:
{
  "errorMessage": "2020-12-05T16:51:55.273Z 281776f1-ee7f-4c8c-8862-a7371d1a8f37 Task timed out after 3.00 seconds"
}

Request ID: "281776f1-ee7f-4c8c-8862-a7371d1a8f37"

Function logs:

START RequestId: 281776f1-ee7f-4c8c-8862-a7371d1a8f37 Version: $LATEST
END RequestId: 281776f1-ee7f-4c8c-8862-a7371d1a8f37
REPORT RequestId: 281776f1-ee7f-4c8c-8862-a7371d1a8f37  Duration: 3003.58 ms    Billed Duration: 3000 ms    Memory Size: 128 MB Max Memory Used: 75 MB  Init Duration: 202.41 ms    
2020-12-05T16:51:55.273Z 281776f1-ee7f-4c8c-8862-a7371d1a8f37 Task timed out after 3.00 seconds

How do I fix this?

Answer 1

This seems like a communication issue.

1. Make sure that the lambda can reach the RDS. Either they are deployed on same VPC, or there is a path from the lambda to the RDS.

2. Make sure that the RDS has a security group with an inbound rule to allow connection from the lambda (protocol, port, ip range or security group)

Also, verify that the lambda has the appropriate privileges (ie AWS IAM Role) to support your desired action.