Tier route tables for Ansible < 2

tier_rt.py

## Usage: lookup('tier_rt', 'dmz1')
import boto
import boto.vpc
import boto.ec2

from sets import Set
from ansible import utils

class LookupModule(object):

    def __init__(self, basedir=None, **kwargs):
        self.basedir = basedir

    def run(self, terms, inject=None, **kwargs):

        terms = utils.listify_lookup_plugin_terms(terms, self.basedir, inject)

        if isinstance(terms, basestring):
           terms = [ terms ]

        ret = [] 

        try:
            vpc = boto.vpc.VPCConnection()
        except Exception, e:
            utils.warnings('Boto authentication issue: %s' % e)

        for term in terms:
            eligible_subnets = vpc.get_all_subnets(filters={"tag:tier": term})

            for subnet in eligible_subnets:
                for rt in vpc.get_all_route_tables(filters={'association.subnet_id': subnet.id}):
                    ret.append(rt.id)
        return Set(ret)