97 lines
2.7 KiB
Python
97 lines
2.7 KiB
Python
import dns.resolver
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import dns.query
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from dns.exception import DNSException
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from .logger import info, warning, error, debug
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import sys
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# Resolve service from mesos-dns SRV record
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# return dict {"servicename": [{"name": "service.f.q.d.n.", "port": 9999}]}
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def resolve(app, conf):
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hosts = {}
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services = app['services']
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domain = conf['domain']
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for service in services:
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hosts[service['name']] = {}
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group = get_group(service, app)
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if group is False:
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error('Group is not defined in config, SUROK_DISCOVERY_GROUP and MARATHON_APP_ID')
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error('Not in Mesos launch?')
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sys.exit(2)
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# Port name from app config
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ports = None
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try:
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ports = service['ports']
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except:
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pass
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# This is fast fix for port naming
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# Will be rewrite later
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fqdn = ''
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if ports is not None:
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for port_name in ports:
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fqdn = '_' + port_name + '.' + '_' + service['name'] + '.' + group + '._tcp.' + domain
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hosts[service['name']][port_name] = do_query(fqdn, conf['loglevel'])
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else:
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fqdn = '_' + service['name'] + '.' + group + '._tcp.' + domain
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hosts[service['name']] = do_query(fqdn, conf['loglevel'])
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return hosts
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# Do SRV queries
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# Return array: [{"name": "f.q.d.n", "port": 8876}]
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def do_query(fqdn, loglevel):
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servers = []
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try:
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resolver = dns.resolver.Resolver()
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resolver.lifetime = 1
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resolver.timeout = 1
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query = resolver.query(fqdn, 'SRV')
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for rdata in query:
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info = str(rdata).split()
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server = {'name': info[3][:-1], 'port': info[2]}
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servers.append(server)
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except DNSException as e:
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if loglevel != 'info':
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error("Could not resolve " + fqdn + ': ' + str(e))
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return servers
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# Groups switch
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# Priority: config, environment, marathon environment
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def get_group(service, app):
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# Check group in app conf
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if 'group' in service:
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return service['group']
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# Check environment variable
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elif app['env'].get('SUROK_DISCOVERY_GROUP'):
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return app['env']['SUROK_DISCOVERY_GROUP']
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# Check marathon environment variable
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elif app['env'].get('MARATHON_APP_ID'):
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group = parse_marathon_app_id(app['env']['MARATHON_APP_ID'])
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return group
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else:
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return False
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# Parse MARATHON_APP_ID
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# Return marathon.group
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def parse_marathon_app_id(marathon_app_id):
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marathon_app_id = marathon_app_id.split('/')
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group = ''
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counter = len(marathon_app_id) - 2
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i = 0
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while counter > i:
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group = group + marathon_app_id[counter]
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if counter != i + 1:
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group += '.'
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counter -= 1
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return group
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