updated : AWS Lambda is not able to connect to MySQL

问题

I was not able to connect to MySQL using AWS Lambda with Node.js.

I had tried configured the security groups for AWS MySQL and Lambda. When I used console.log it shows correct response from the data base as the data from db : rk, but when I tried to test it was not showing the correct response.

Below was the logs and the index.js files and logs. Can anybody please guide me ?

index.js (i had updated my code as below ):

var mysql = require('mysql');
var pool  = mysql.createPool({
    host     : 'mydbinstancelamda.connqa9taxeg.us-east-1.rds.amazonaws.com',
    user     : 'admin',
    password : 'password',
    database : 'dbname'
  });

exports.handler =  (event, context, callback)=> {


pool.getConnection(function(err, connection) {
    if (err) throw err;

var queryString = "SELECT emp_name from employee where emp_name='rk'";    
        connection.query(queryString, function(err, rows, fields) {
        if (err) throw err;
        console.log("the data from db : " + rows[0].emp_name);
        callback(null);
        connection.release(); 
    });
});
};

error :

Response:
{
  "errorMessage": "2018-06-11T02:34:19.817Z ef864d3d-6d1f-11e8-b6e3-97ac89a0f544 Task timed out after 3.00 seconds"
}

Request ID:
"ef864d3d-6d1f-11e8-b6e3-97ac89a0f544"
Function Logs:
START RequestId: ef864d3d-6d1f-11e8-b6e3-97ac89a0f544 Version: $LATEST
dadf1a33-6d22-11e8-869d-7d7e31ccaf6e    the data from db : rk
END

回答1:

Try changing the lambda execution timeout from lambda console as shown in the below picture:

Make sure that security group of RDS MySQL DB is allowing connections from Lambda's security group, if there are the same then you are good to go.

UPDATE: You need to call callback after the MySQL returns the response.

// change following line:
exports.handler =  (event, context, req,res,callback)=> {
// To this line:
exports.handler =  (event, context, callback)=> {

After the work is finished, You need to callback to tell lambda that work is complete:

callback(undefined, result);

Example: https://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-handler.html#nodejs-prog-model-handler-example

回答2:

i followed my instructions given by @Dilip Kola , were my mistakes are not closing the pool , handler arguments !...

my complete code looks like now :

var mysql = require('mysql');
var pool  = mysql.createPool({
    host     : 'url for mysql ',
    user     : 'username ',
    password : 'paswrod ',
    database : 'database-name'
  });

exports.handler =  (event, context, callback)=> {


pool.getConnection(function(err, connection) {
    if (err) throw err;
var queryString = "SELECT emp_name from employee where emp_name='rk'";    
        connection.query(queryString, function(err, rows, fields) {
        if (err) throw err;
        console.log("the data from db : " + rows[0].emp_name); 
        connection.release(); 
        pool.end();
        callback(null,rows[0].emp_name);

    });
});
};

finally i got my output as :

来源：https://stackoverflow.com/questions/50789982/updated-aws-lambda-is-not-able-to-connect-to-mysql

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