tmpFile.py

"""Simple failure detector"""
import time
import zmq


def pingo(url, hosts, node_id):
    ctx = zmq.Context.instance()
    server = ctx.socket(zmq.REP)
    server.bind(url)

    while True:
        hosts_status = {}

        # initial status
        status = {h: (False if h != url else True) for h in hosts }
        token = 1

        # initial tokens
        for host in hosts:
            hosts_status[host] = '%s-%i' % (host, token)
            token += 1

        for host in hosts:
            client = ctx.socket(zmq.REQ)
            # not my ip
            if host != url:

                client.connect(host)

                # send heartbeat to peer
                client.send_string('%s' % hosts_status[host])

                # receive acknowledgement
                try:
                    msg = server.recv()
                except ConnectionRefusedError:
                    msg = b''
                # print(msg, hosts_status[host])
                for k, v in hosts_status.items():
                    print(msg.decode("utf-8"), v)
                    if msg.decode("utf-8") == v:
                        status[host] = True
                        print('ID: %d --- %s live!' % (node_id, host))

                time.sleep(0.1)
                client.close()

        for h in hosts:
            if h != url:
                if not status[h]:
                    pass
                    # print('ID: %d --- %s down!' % (node_id, h))
    server.close()


nodes = ['tcp://127.0.0.1:5550',
         'tcp://127.0.0.1:5551',
         'tcp://127.0.0.1:5552',
         'tcp://127.0.0.1:5553'
         ]

pingo('tcp://127.0.0.1:5550', nodes, 1)