Init the connection to the CouchDB server.

def init(self):
        """Init the connection to the CouchDB server."""
        if not self.export_enable:
            return None

        server_uri = 'tcp://{}:{}'.format(self.host, self.port)

        try:
            self.context = zmq.Context()
            publisher = self.context.socket(zmq.PUB)
            publisher.bind(server_uri)
        except Exception as e:
            logger.critical("Cannot connect to ZeroMQ server %s (%s)" % (server_uri, e))
            sys.exit(2)
        else:
            logger.info("Connected to the ZeroMQ server %s" % server_uri)

        return publisher