surok/surok/discovery.py

import dns.resolver


# Resolve service from mesos-dns SRV record
# return dict {"servicename": [{"name": "service.f.q.d.n", "port": 9999}]}
def resolve(app, conf):
    hosts = {}
    services = app['services']
    domain = conf['domain']
    for service in services:
        hosts[service['name']] = []
        try:
            for rdata in dns.resolver.query('_' +
                                            service['name'] + '.' +
                                            service['group'] + '._tcp.' +
                                            domain, 'SRV'):
                info = str(rdata).split()
                server = {'name': info[3], 'port': info[2]}

                hosts[service['name']].append(server)
        except Exception as e:
            print(str(e) + ": Could not resolve " +
                  service['name'] + '.' +
                  service['group'] + '._tcp.' + domain)

    return hosts