def update_vpc_rt()

in functions/source/lambda_function.py [0:0]

• 32 lines of code
• 10 McCabe index (conditional complexity)

def update_vpc_rt(vpn_routes, vmx_id, rt_id):
    region = os.environ['AWS_REGION']
    ec2 = boto3.client('ec2', region_name=region)
    uniq_vpn_routes = list(set(vpn_routes))
    #Checking exsisting routes in the VPC table
    raw_exsisting_vpc_rts = ec2.describe_route_tables(Filters = [{"Name": "route-table-id", "Values": [rt_id]}])['RouteTables'][0]['Routes']
    exsisting_routes = []
    for routes in raw_exsisting_vpc_rts:
        if 'InstanceId' in routes and routes['InstanceId'] == vmx_id:
            exsisting_routes.append(routes['DestinationCidrBlock'])
        else:
            logger.info('VPC RT: No matching routes found')
    #Compare exsisting routes with new routes
    update_routes = [x for x in exsisting_routes + uniq_vpn_routes if x not in exsisting_routes]
    if update_routes:
        logger.info('VPC RT: New routes for update {0}'.format(update_routes))
        for routes in update_routes:
            try:
                ec2.create_route(
                DestinationCidrBlock=routes,
                InstanceId=vmx_id,
                RouteTableId=rt_id
              )
            except botocore.exceptions.ClientError as error:
                if error.response['Error']['Code'] == 'RouteAlreadyExists':
                    ec2.replace_route(
                    DestinationCidrBlock=routes,
                    InstanceId=vmx_id,
                    RouteTableId=rt_id
                )
                else:
                    logger.info('VPC RT: Boto exception, adding routes to vpc table failed due to {0}'.format(error.response['Error']['Code'])) 
    else:
        logger.info('VPC RT: No new routes for update')