AWS Step function - Create RDS instance , wait till available and finally take snapshot.

We need three lambda function
1) Create RDS instance
2) Wait function - check that RDS instance is available or not
3) Create Snapshot

  1)  Create RDS DB instance  - :test_create_dbinstance

import boto3

import datetime

import time

def lambda_handler(event, context):

    client = boto3.client('rds')

    client.create_db_instance(DBInstanceIdentifier=’testRDS1234’,

                                    AllocatedStorage =200,

                                    DBInstanceClass='db.m4.large',

                                    MasterUsername='sa',

                                    MasterUserPassword=abcdert',

                                    Port=1433,

                                    Engine='sqlserver-se',

                                    DBSubnetGroupName='test_rds_subnet_group',

                                    LicenseModel='license-included'

                                )

    return

  2) Lambda function to check that RDS instance is fully available or not - test_dbinstance_poll

import boto3

import datetime

import time

def lambda_handler(event, context):

      client = boto3.client('rds')

    status=False

    response = client.describe_db_instances(DBInstanceIdentifier = ’testRDS1234’)

    for DBInstance in response['DBInstances']:

        if (DBInstance['DBInstanceStatus'] == 'available'):

            status=True

    return status

3 Create snapshot  - test_rds_snapshot

import boto3 

import datetime 

import time 

import sys

def lambda_handler(event, context): 

    client = boto3.client('rds')

    date=time.strftime("%Y-%m-%d-%H-%M-%S")

    snapshot_name = ’testRDS1234’+date   

    print (snapshot_name)

   

    response = client.create_db_snapshot(

    DBSnapshotIdentifier= snapshot_name,

    DBInstanceIdentifier=’testRDS1234’,

        Tags=[

                {

                'Key': ‘RDS’,

                'Value': 'snapshot'

                }

            ]

    )

Now you have all 3 function. Now create step function and execute

{

  "Comment": "A state machine that submits a Job to AWS Batch and monitors the Job until it completes.",

  "StartAt": "createinstance",

  "States": {

    "createinstance": {

      "Type": "Task",

      "Resource": "arn:aws:lambda:us-east-1:<<accounted>>:function:test_create_dbinstance",

      "ResultPath": "$.guid",

      "Next": "Wait X Seconds"

    },

    "Wait X Seconds": {

      "Type": "Wait",

      "Seconds": 300,

      "Next": "Get Job Status"

    },

    "Get Job Status": {

      "Type": "Task",

      "Resource": "arn:aws:lambda:us-east-1:<<accounted>>:function:test_dbinstance_poll",

      "Next": "Job Complete?",

      "InputPath": "$.guid",

      "ResultPath": "$.status"

    },

    "Job Complete?": {

      "Type": "Choice",

      "Choices": [

        {

          "Variable": "$.status",

          "StringEquals": "FAILED",

          "Next": "Job Failed"

        },

        {

          "Variable": "$.status",

          "BooleanEquals": true,

          "Next": "Get Final Job Status"

        }

      ],

      "Default": "Wait X Seconds"

    },

    "Job Failed": {

      "Type": "Fail",

      "Cause": "AWS Batch Job Failed",

      "Error": "DescribeJob returned FAILED"

    },

    "Get Final Job Status": {

      "Type": "Task",

      "Resource": "arn:aws:lambda:us-east-1:<<accounted>>:function:test_rds_snapshot",

      "InputPath": "$.guid",

      "End": true

    }

  }

}

Below policy attached with Lambda functions

{

    "Version": "2012-10-17",

    "Statement": [

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "logs:CreateLogGroup",

                "logs:CreateLogStream",

                "logs:PutLogEvents"

            ],

            "Resource": [

                "*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "ec2:CreateNetworkInterface",

                "ec2:DeleteNetworkInterface",

                "ec2:DescribeNetworkInterfaces"

            ],

            "Resource": [

                "*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "rds:DescribeDBInstances",

                "rds:DescribeDBSnapshots"

            ],

            "Resource": [

                "*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "rds:CreateDBSnapshot",

                "rds:CreateDBInstance",

                "rds:CopyDBSnapshot",

                "rds:DeleteDBSnapshot"

            ],

            "Resource": [

                "*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "rds:CreateDBSnapshot"

            ],

            "Resource": [

                "*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "rds:CopyDBSnapshot",

                "rds:DeleteDBSnapshot"

            ],

            "Resource": [

                "arn:aws:rds:us-east-1:*:snapshot:*"

            ]

        },

        {

            "Sid": "abcd",

            "Effect": "Allow",

            "Action": [

                "events:DescribeRule"

            ],

            "Resource": [

                "arn:aws:events:*:*:rule/*"

            ]

        }

    ]

}