zmonitor(3)

zmonitor(3)

CZMQ Manual - CZMQ/4.0.3

Name

zmonitor - Class for socket event monitor

Synopsis

//  Create new zmonitor actor instance to monitor a zsock_t socket:
//
//      zactor_t *monitor = zactor_new (zmonitor, mysocket);
//
//  Destroy zmonitor instance.
//
//      zactor_destroy (&monitor);
//
//  Enable verbose logging of commands and activity.
//
//      zstr_send (monitor, "VERBOSE");
//
//  Listen to monitor event type (zero or types, ending in NULL):
//      zstr_sendx (monitor, "LISTEN", type, ..., NULL);
//
//      Events:
//      CONNECTED
//      CONNECT_DELAYED
//      CONNECT_RETRIED
//      LISTENING
//      BIND_FAILED
//      ACCEPTED
//      ACCEPT_FAILED
//      CLOSED
//      CLOSE_FAILED
//      DISCONNECTED
//      MONITOR_STOPPED
//      ALL
//
//  Start monitor; after this, any further LISTEN commands are ignored.
//
//      zstr_send (monitor, "START");
//      zsock_wait (monitor);
//
//  Receive next monitor event:
//
//      zmsg_t *msg = zmsg_recv (monitor);
//
//  This is the zmonitor constructor as a zactor_fn; the argument can be
//  a zactor_t, zsock_t, or libzmq void * socket:
CZMQ_EXPORT void
    zmonitor (zsock_t *pipe, void *sock);

//  Selftest
CZMQ_EXPORT void
    zmonitor_test (bool verbose);
Please add '@interface' section in './../src/zmonitor.c'.

Description

The zmonitor actor provides an API for obtaining socket events such as connected, listen, disconnected, etc. Socket events are only available for sockets connecting or bound to ipc:// and tcp:// endpoints.

This class wraps the ZMQ socket monitor API, see zmq_socket_monitor for details. Works on all versions of libzmq from 3.2 onwards. This class replaces zproxy_v2, and is meant for applications that use the CZMQ v3 API (meaning, zsock).

Example

From zmonitor_test method

zsock_t *client = zsock_new (ZMQ_DEALER);
assert (client);
zactor_t *clientmon = zactor_new (zmonitor, client);
assert (clientmon);
if (verbose)
 zstr_sendx (clientmon, "VERBOSE", NULL);
zstr_sendx (clientmon, "LISTEN", "LISTENING", "ACCEPTED", NULL);
#if defined (ZMQ_EVENT_HANDSHAKE_SUCCEED)
zstr_sendx (clientmon, "LISTEN", "HANDSHAKE_SUCCEED", NULL);
#endif
zstr_sendx (clientmon, "START", NULL);
zsock_wait (clientmon);

zsock_t *server = zsock_new (ZMQ_DEALER);
assert (server);
zactor_t *servermon = zactor_new (zmonitor, server);
assert (servermon);
if (verbose)
 zstr_sendx (servermon, "VERBOSE", NULL);
zstr_sendx (servermon, "LISTEN", "CONNECTED", "DISCONNECTED", NULL);
zstr_sendx (servermon, "START", NULL);
zsock_wait (servermon);

// Allow a brief time for the message to get there...
zmq_poll (NULL, 0, 200);

// Check client is now listening
int port_nbr = zsock_bind (client, "tcp://127.0.0.1:*");
assert (port_nbr != -1);
s_assert_event (clientmon, "LISTENING");

// Check server connected to client
zsock_connect (server, "tcp://127.0.0.1:%d", port_nbr);
s_assert_event (servermon, "CONNECTED");

// Check client accepted connection
s_assert_event (clientmon, "ACCEPTED");
#if defined (ZMQ_EVENT_HANDSHAKE_SUCCEED)
s_assert_event (clientmon, "HANDSHAKE_SUCCEED");
#endif

zactor_destroy (&clientmon);
zactor_destroy (&servermon);
zsock_destroy (&client);
zsock_destroy (&server);
#endif

#if defined (__WINDOWS__)
zsys_shutdown(); #endif

Authors

The czmq manual was written by the authors in the AUTHORS file.

Resources

Main web site:

Report bugs to the email <gro.qmorez.stsil|ved-qmorez#gro.qmorez.stsil|ved-qmorez>

Copyright

Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for ØMQ: http://czmq.zeromq.org. This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.