Source code for obci.control.launcher.server_scanner

#!/usr/bin/python
# -*- coding: utf-8 -*-

import zmq
import time
import socket
import select

from obci.control.common.message import OBCIMessageTool, send_msg
from obci.control.launcher.launcher_messages import message_templates


UPDATE_INTERVAL = 8
_LOOPS = 3

ALLOWED_SILENCE = 45


def update_nearby_servers(srv_data, bcast_port, ctx=None, update_push_addr=None):
    mtool = OBCIMessageTool(message_templates)

    loops_to_update = _LOOPS

    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.bind(('', bcast_port))

    notify_sock = None
    if update_push_addr is not None:
        ctx = ctx if ctx else zmq.Context()
        notify_sock = ctx.socket(zmq.PUSH)
        notify_sock.connect(update_push_addr)

    while True:
        changed = False
        try:
            inp, out, exc = select.select([s], [], [], UPDATE_INTERVAL / _LOOPS)
        except Exception as e:
            srv_data.logger.critical("nearby_servers_update - exception: %s", str(e))
            srv_data.logger.critical("nearby_servers - aborting")
            return

        if s in inp:
            data, wherefrom = s.recvfrom(1500, 0)
            msg = data[:-1]
            message = mtool.unpack_msg(msg)
            changed = srv_data.update(ip=wherefrom[0], hostname=message.sender_ip,
                                      uuid=message.sender, rep_port=message.rep_port,
                                      pub_port=message.pub_port)

        else:
            # print "no data"
            pass

        loops_to_update -= 1

        if loops_to_update == 0:
            loops_to_update = _LOOPS
            changed = srv_data.clean_silent()

        if changed:
            send_msg(notify_sock, mtool.fill_msg('nearby_machines',
                                                 nearby_machines=srv_data.dict_snapshot()))

    s.close()


def broadcast_server(server_uuid, rep_port, pub_port, bcast_port):
    mtool = OBCIMessageTool(message_templates)

    str_msg = mtool.fill_msg("server_broadcast", sender_ip=socket.gethostname(), sender=server_uuid,
                             rep_port=rep_port, pub_port=pub_port)
    str_msg += b'\n'

    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.bind(('', 0))
    s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

    # introduction
    for i in range(10):
        try:
            s.sendto(str_msg, ('<broadcast>', bcast_port))
        except socket.error as e:
            pass
        time.sleep(0.3)

    # updates
    while True:
        try:
            s.sendto(str_msg, ('<broadcast>', bcast_port))
        except socket.error as e:
            print("[obci_server] Cannot broadcast obci_server, will try again in 1min:", str(e))
            time.sleep(53)
        time.sleep(7)

    s.close()