Find EC2 Private IPs from DNS or ELB Name or Tag Name

ec2ip.py

#!/usr/bin/env python
from argparse import ArgumentParser
from boto.ec2 import EC2Connection
from boto.ec2.elb import ELBConnection
from socket import gethostbyname
from sys import argv


class NodeLookup:

    def __init__(self, query):
        self.elb_connection = ELBConnection()
        self.ec2_connection = EC2Connection()
        for function in [self.search_by_elb_name, self.search_by_dns_entry, self.search_by_tag_name]:
            try:
                return function(query)
            except:
                pass


    def search_by_dns_entry(self, dns_entry):
        ip_address = gethostbyname(dns_entry)
        try:
            elb_name = self.ec2_connection.get_all_network_interfaces(filters={'private_ip_address': ip_address})[0].description[4:]
        except IndexError:
            elb_name = self.ec2_connection.get_all_network_interfaces(filters={'association.public-ip': ip_address})[0].description[4:]
        self.search_by_elb_name(elb_name)


    def search_by_elb_name(self, elb_name):
        elb = self.elb_connection.get_all_load_balancers(load_balancer_names=[elb_name])[0]
        ec2_nodes = self.ec2_connection.get_all_instances(instance_ids=[i.id for i in elb.instances])
        self.print_nodes(ec2_nodes)


    def search_by_tag_name(self, tag_name):
        ec2_nodes = self.ec2_connection.get_all_instances(filters={"tag:Name" : tag_name})
        self.print_nodes(ec2_nodes)


    def print_nodes(self, nodes):
        for ip in [i.instances[0].private_ip_address for i in nodes]:
            print ip


if __name__ == '__main__':
    parser = ArgumentParser(description='Find EC2 Private IP Addresses.')
    parser.add_argument('query', type=str, help='Search for EC2 nodes by any of: DNS, ELB Name, or Name Tag')
    args = parser.parse_args()
    lookup = NodeLookup(args.query)