resolve-ec2 - turns command line parameters into IP addresses (Name tags or instance IDs). Intended to be used in conjunction with ssh-ec2 and mux

resolve-ec2

#!/usr/bin/env python

from boto import ec2
from functools import wraps
import re

def ip4(wrapped_func):
    def _dec(request, *args, **kwargs):
        response = wrapped_func(request, *args, **kwargs)
        return [i.private_ip_address for i in response]
    return wraps(wrapped_func)(_dec)

class AWSResolver(object):

    def __init__(self, region='eu-west-1'):
        self.region = region
        self.ec2 = ec2.connect_to_region(self.region)

    @ip4
    def instance_by_name_tag(self, tag):
        return self.ec2.get_only_instances(filters={'tag:Name': tag})

    @ip4
    def instance_by_id(self, instance_id):
        return self.ec2.get_only_instances(instance_id)

    def resolve(self, *instance_spec):
        matchers = {
            r'^i-[a-f0-9]+$': self.instance_by_id,
            r'.*': self.instance_by_name_tag
        }
        results = []
        for inst in instance_spec:
            for pattern, resolver in matchers.iteritems():
                if re.match(pattern, inst):
                    results.extend(resolver(inst))
                    break
        return results

a = AWSResolver()

import sys
query = sys.argv
query.pop(0)

print '\n'.join(a.resolve(*query))