Example Lambda Custom Resource to create a MySQL database on RDS

create_db.py

import json
import MySQLdb
import os
import requests


def handler(event, context):
    if event['RequestType'] == 'Create' or event['RequestType'] == 'Update':
        parameters = event['ResourceProperties']
        create_db(
            user=parameters['DBUsername'],
            passwd=parameters['DBPassword'],
            host=parameters['DBHost'],
            port=parameters['DBPort'],
            db_name=parameters['DBName']
        )

        send_response(
            event,
            context,
            "SUCCESS",
            "Resource %s successful" % event['RequestType']
        )
    elif event['RequestType'] == 'Delete':
        send_response(
            event,
            context,
            "SUCCESS",
            "Resource %s successful" % event['RequestType']
        )
    else:
        send_response(
            event,
            context,
            "FAILED",
            "Resource %s failed" % event['RequestType']
        )


def send_response(event, context, response_status, response_data):
    '''Send a resource manipulation status response to CloudFormation'''
    response_body = json.dumps(
        {
            "Status": response_status,
            "Reason": context.log_stream_name,
            "StackId": event['StackId'],
            "RequestId": event['RequestId'],
            "LogicalResourceId": event['LogicalResourceId'],
            "Data": {"Message": response_data}

        }
    )

    headers = {
        "Content-Type": '',
        "Content-Length": len(response_body)
    }

    requests.put(
        event['ResponseURL'],
        headers=headers,
        data=response_body
    )


def create_db(user, passwd, host, port, db_name):
    db = MySQLdb.connect(
        user=os.environ['DB_USERNAME'],
        passwd=os.environ['DB_PASSWORD'],
        host=os.environ['DB_HOST'],
        port=os.environ['DB_PORT']
    )
    cursor = db.cursor()
    cursor.execute('CREATE DATABASE IF NOT EXISTS %s' % db_name)