Search which Security groups have 0.0.0.0/0 incoming, and figure out which instances use them

sec_grp_scan.py

#!/usr/bin/python3

import boto3

ec2_client = boto3.client('ec2')

def find_in_sg(ip_address):
    sg = ec2_client.describe_security_groups()
    security_groups = []
    for group in sg['SecurityGroups']:
        for permission in group['IpPermissions']:
            for range in permission['IpRanges']:
                if ip_address in range['CidrIp']:
                    security_groups.append(group['GroupName'])
    return set(security_groups)

def sg_instance_search(security_group):
    response = ec2_client.describe_instances(
        Filters=[{
                'Name': 'instance.group-name',
                'Values': [ security_group ]
            },
        ]
    )
    result = []
    for reservation in response['Reservations']:
        result.append(reservation['Instances'])
    return(result)

def is_instance_private(instance_obj):
    if 'PublicIpAddress' in instance_obj:
        return False
    else:
        return True

def get_instance_name(instance_obj):
    for pair in instance_obj['Tags']:
        if pair['Key'] == 'Name':
            return pair['Value']
        

def print_heading():
    print('Instance ID         Security Group                Public IP       Instance Name  ')
    print('------------        ---------------               ----------      -------------- ')

def get_spaces(desired_length, input_string):
    length = len(input_string)
    return desired_length - length

def main():
    print_heading()
    results = find_in_sg('0.0.0.0/0')
    for level_1 in results:
        instances = sg_instance_search(level_1)
            # now to get out of the hole we've dug ourselves into with all the nested lists
        if len(instances) > 0:
            for list1 in instances:
                for instance in list1:
                    if not is_instance_private(instance):
                        print(
                            instance['InstanceId'] + 
                            ' ' * get_spaces(20, instance['InstanceId']) + 
                            level_1 + 
                            ' ' * get_spaces(30, level_1) + 
                            instance['PublicIpAddress'] +
                            ' ' * get_spaces(16, instance['PublicIpAddress']) + 
                            get_instance_name(instance)
                            )
        
main()