CODE EXAMPLE FOR PYTHON

Sequential Execution EC2

import time
import boto3

class VolumesSequential(object):
    """Finds total volume size for all EC2 instances"""
    def __init__(self):
        self.ec2 = boto3.resource('ec2')

    def instance_volumes(self, instance):
        """
        Finds total size of the EBS volumes attached
        to an EC2 instance
        """
        instance_total = 0
        for volume in instance.volumes.all():
            instance_total += volume.size
        return instance_total

    def total_size(self):
        """
        Lists all EC2 instances in the default region
        and sums result of instance_volumes
        """
        print "Running sequentially"
        instances = self.ec2.instances.all()
        instances_total = 0
        for instance in instances:
            instances_total += self.instance_volumes(instance)
        return instances_total

def lambda_handler(event, context):
    volumes = VolumesSequential()
    _start = time.time()
    total = volumes.total_size()
    print "Total volume size: %s GB" % total
    print "Sequential execution time: %s seconds" % (time.time() - _start)