surok/surok/system.py

import os
import sys
import requests
from .discovery import Discovery
from .logger import Logger

logger=Logger()

# Get old configuration
def get_old(name, service_conf):
    try:
        path = '/var/tmp/surok.' + name
        f = open(path, 'r')
        old = f.read()
        f.close()
    except Exception as e:
        logger.error(str(e))
        return 0

    if old == service_conf:
        return 1
    else:
        return 0


# Get old discovered servers from memcache
def get_old_from_memcache(mc, name, app_hosts):
    mc_servers_key = 'surok_' + name + '_servers'
    new_servers = []
    old_servers = mc.get(mc_servers_key)
    for service in app_hosts:
        for server in app_hosts[service]:
            new_servers.append(server['name'] + ':' + server['port'])

    for server in new_servers:
        if server not in old_servers:
            write_confs_to_memcache(mc, new_servers, mc_servers_key)
            return 0

    return 1


# Write to memcache
def write_confs_to_memcache(mc, servers, key):
    mc.set(key, servers)


def write_lock(name, service_conf):
    path = '/var/tmp/surok.' + name
    f = open(path, 'w')
    f.write(service_conf)
    f.close()


def do_reload(service_conf, app_conf):
    logger.warning('Write new configuration of ' + app_conf['conf_name'])

    f = open(app_conf['dest'], 'w')
    f.write(service_conf)
    f.close()

    write_lock(app_conf['conf_name'], service_conf)

    # Reload conf
    stdout = os.popen(app_conf['reload_cmd']).read()
    return stdout


# Discovery memcached servers
def discovery_memcached(conf):
    discovery=Discovery()
    memcache = conf['memcached']
    app_conf = {
        "services": [
            {
                "name": memcache['discovery']['service'],
                "group": memcache['discovery']['group']
            }
        ]
    }

    hosts = discovery.resolve(app_conf)
    mc_servers = []

    for server in hosts[memcache['discovery']['service']]:
        mc_server = server['name'] + ':' + server['port']
        mc_servers.append(mc_server)

    return mc_servers


# !!! NEED REFACTORING !!!
def reload_conf(service_conf, app_conf, conf, app_hosts):
    # Check marathon enabled in configuration
    if (conf.get('version','0.7')=='0.8' and conf['marathon'].get('restart',False)) or (
        conf.get('version','0.7')=='0.7' and conf['marathon'].get('enable',False)):
        if get_old(app_conf['conf_name'], service_conf) != 1:
            restart_self_in_marathon(conf['marathon'])

    # Check memcache
    # Need rewriting
    ################
    if 'memcached' in conf:
        if conf['memcached']['enabled'] is True:
            import memcache
            # Check old servers
            mc_hosts = None
            if conf['memcached']['discovery']['enabled'] is True:
                mc_hosts = discovery_memcached(conf)
                logger.info('Discovered memcached hosts: ' + str(mc_hosts))
            else:
                mc_hosts = conf['memcached']['hosts']
            try:
                mc = memcache.Client(mc_hosts)
                if get_old_from_memcache(mc, app_conf['conf_name'], app_hosts) != 1:
                    stdout = do_reload(service_conf, app_conf)
                    logger.info(stdout)
                    return True
            except Exception as e:
                logger.error('Cannot connect to memcached: ' + str(e))

    else:
        logger.warning('DEPRECATED main conf file. Please use new syntax!')
        # End of memcache block
        #######################

    if get_old(app_conf['conf_name'], service_conf) != 1:
        stdout = do_reload(service_conf, app_conf)
        logger.info(stdout)
        return True
    else:
        logger.debug('Same config ' + app_conf['conf_name'] + ' Skip reload')
        return False

# Do POST request to marathon API
# /v2/apps//app/name/restart
def restart_self_in_marathon(marathon):
    # Check MARATHON_APP_ID environment varible
    if not os.environ.get('MARATHON_APP_ID',False):
        logger.error('Cannot find MARATHON_APP_ID. Not in Mesos?')
        sys.exit(2)
    # Ok. In this step we made restart request to Marathon
    r = requests.post('http://'+marathon['host']+'/v2/apps/'+os.environ['MARATHON_APP_ID']+'/restart',
                      data={'force': marathon.get('force',False)})