# Lambda Code for Lab 5 (SysOps)

### Lambda.py

import json
import botocore
import boto3

backup = boto3.client('backup')

def lambda_handler(event, context):
    print ('Incoming Event:' + json.dumps(event))

    try:
        if event['Records'][0]['Sns']['Subject'] == 'Restore Test Status':
            print ('No action required, deletion of new resource confirmed.')
            return
    except Exception as e:
            print (str(e))
            return

    job_type = event['Records'][0]['Sns']['Message'].split('.')[-1].split(' ')[1]

    try:
        if 'failed' in event['Records'][0]['Sns']['Message']:
            print ('Something has failed. Please review the job in the AWS Backup console.')
            return 'Job ID:' + event['Records'][0]['Sns']['Message'].split('.')[-1].split(':')[1].strip()
        elif job_type == 'Backup':
            backup_job_id = event['Records'][0]['Sns']['Message'].split('.')[-1].split(':')[1].strip()
            backup_info = backup.describe_backup_job(
                            BackupJobId=backup_job_id
                        )
            #get backup job details
            recovery_point_arn = backup_info['RecoveryPointArn']
            iam_role_arn = backup_info['IamRoleArn']
            backup_vault_name = backup_info['BackupVaultName']
            resource_type = backup_info['ResourceType']

            metadata = backup.get_recovery_point_restore_metadata(
                BackupVaultName=backup_vault_name,
                RecoveryPointArn=recovery_point_arn
            )

            #determine resource type that was backed up and get corresponding metadata
            if resource_type == 'DynamoDB':
                metadata['RestoreMetadata']['targetTableName'] = metadata['RestoreMetadata']['originalTableName'] + '-restore-test'
            elif resource_type == 'EBS':
                ec2 = boto3.client('ec2')
                region = event['Records'][0]['Sns']['TopicArn'].split(':')[3]
                volumeid = event['Records'][0]['Sns']['Message'].split('.')[2].split('/')[1]

                metadata['RestoreMetadata']['availabilityZone'] = ec2.describe_volumes(
                VolumeIds=[
                    volumeid
                ]
                )['Volumes'][0]['AvailabilityZone']
            elif resource_type == 'RDS':
                metadata['RestoreMetadata']['DBInstanceIdentifier'] = event['Records'][0]['Sns']['Message'].split('.')[2].split(':')[7] + '-restore-test'
            elif resource_type == 'EFS':
                metadata['RestoreMetadata']['PerformanceMode'] = 'generalPurpose'
                metadata['RestoreMetadata']['newFileSystem'] = 'true'
                metadata['RestoreMetadata']['Encrypted'] = 'false'
                metadata['RestoreMetadata']['CreationToken'] = metadata['RestoreMetadata']['file-system-id'] + '-restore-test'

            #API call to start the restore job
            print ('Starting the restore job')
            restore_request = backup.start_restore_job(
                    RecoveryPointArn=recovery_point_arn,
                    IamRoleArn=iam_role_arn,
                    Metadata=metadata['RestoreMetadata']
            )

            print (json.dumps(restore_request))
            return

        elif job_type == 'Restore':
            restore_job_id = event['Records'][0]['Sns']['Message'].split('.')[-1].split(':')[1].strip()
            topic_arn = event['Records'][0]['Sns']['TopicArn']
            restore_info = backup.describe_restore_job(
                            RestoreJobId=restore_job_id
                        )
            resource_type = restore_info['CreatedResourceArn'].split(':')[2]

            print ('Restore from the backup was successful. Deleting the newly created resource.')

        #determine resource type that was restored and delete it to save cost
        if resource_type == 'dynamodb':
            dynamo = boto3.client('dynamodb')
            table_name = restore_info['CreatedResourceArn'].split(':')[5].split('/')[1]
            print ('Deleting: ' + table_name)
            delete_request = dynamo.delete_table(
                                TableName=table_name
                            )
        elif resource_type == 'ec2':
            ec2 = boto3.client('ec2')
            volume_id = restore_info['CreatedResourceArn'].split(':')[5].split('/')[1]
            print ('Deleting: ' + volume_id)
            delete_request = ec2.delete_volume(
                        VolumeId=volume_id
                    )
        elif resource_type == 'rds':
            rds = boto3.client('rds')
            database_identifier = restore_info['CreatedResourceArn'].split(':')[6]
            print ('Deleting: ' + database_identifier)
            delete_request = rds.delete_db_instance(
                        DBInstanceIdentifier=database_identifier,
                        SkipFinalSnapshot=True
                    )
        elif resource_type == 'elasticfilesystem':
            efs = boto3.client('efs')
            elastic_file_system = restore_info['CreatedResourceArn'].split(':')[5].split('/')[1]
            print ('Deleting: ' + elastic_file_system)
            delete_request = efs.delete_file_system(
                        FileSystemId=elastic_file_system
                    )

        sns = boto3.client('sns')

        print ('Sending deletion confirmation')
        #send a final notification confirming deletion of the newly restored resource
        notify = sns.publish(
            TopicArn=topic_arn,
            Message='Restore from ' + restore_info['RecoveryPointArn'] + ' was successful. The newly created resource ' + restore_info['CreatedResourceArn'] + ' has been cleaned up.' ,
            Subject='Restore Test Status'
        )

        print (json.dumps(notify))

        print (json.dumps(delete_request))
        return
    except Exception as e:
        print (str(e))
        return