mirror of
https://github.com/zeromq/libzmq.git
synced 2024-12-12 18:40:27 +01:00
240 lines
7.3 KiB
Plaintext
240 lines
7.3 KiB
Plaintext
zmq_socket_monitor(3)
|
|
=====================
|
|
|
|
|
|
NAME
|
|
----
|
|
|
|
zmq_socket_monitor - monitor socket events
|
|
|
|
|
|
SYNOPSIS
|
|
--------
|
|
*int zmq_socket_monitor (void '*socket', char '*endpoint', int 'events');*
|
|
|
|
|
|
DESCRIPTION
|
|
-----------
|
|
The _zmq_socket_monitor()_ method lets an application thread track
|
|
socket events (like connects) on a ZeroMQ socket. Each call to this
|
|
method creates a 'ZMQ_PAIR' socket and binds that to the specified
|
|
inproc:// 'endpoint'. To collect the socket events, you must create
|
|
your own 'ZMQ_PAIR' socket, and connect that to the endpoint.
|
|
|
|
The 'events' argument is a bitmask of the socket events you wish to
|
|
monitor, see 'Supported events' below. To monitor all events, use the
|
|
event value ZMQ_EVENT_ALL.
|
|
|
|
Each event is sent as two frames. The first frame contains an event
|
|
number (16 bits), and an event value (32 bits) that provides additional
|
|
data according to the event number. The second frame contains a string
|
|
that specifies the affected TCP or IPC endpoint.
|
|
|
|
----
|
|
The _zmq_socket_monitor()_ method supports only connection-oriented
|
|
transports, that is, TCP, IPC, and TIPC.
|
|
----
|
|
|
|
Supported events
|
|
----------------
|
|
|
|
ZMQ_EVENT_CONNECTED
|
|
~~~~~~~~~~~~~~~~~~~
|
|
The socket has successfully connected to a remote peer. The event value
|
|
is the file descriptor (FD) of the underlying network socket. Warning:
|
|
there is no guarantee that the FD is still valid by the time your code
|
|
receives this event.
|
|
|
|
ZMQ_EVENT_CONNECT_DELAYED
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
A connect request on the socket is pending. The event value is unspecified.
|
|
|
|
ZMQ_EVENT_CONNECT_RETRIED
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
A connect request failed, and is now being retried. The event value is the
|
|
reconnect interval in milliseconds. Note that the reconnect interval is
|
|
recalculated at each retry.
|
|
|
|
ZMQ_EVENT_LISTENING
|
|
~~~~~~~~~~~~~~~~~~~
|
|
The socket was successfully bound to a network interface. The event value
|
|
is the FD of the underlying network socket. Warning: there is no guarantee
|
|
that the FD is still valid by the time your code receives this event.
|
|
|
|
ZMQ_EVENT_BIND_FAILED
|
|
~~~~~~~~~~~~~~~~~~~~~
|
|
The socket could not bind to a given interface. The event value is the
|
|
errno generated by the system bind call.
|
|
|
|
ZMQ_EVENT_ACCEPTED
|
|
~~~~~~~~~~~~~~~~~~
|
|
The socket has accepted a connection from a remote peer. The event value is
|
|
the FD of the underlying network socket. Warning: there is no guarantee that
|
|
the FD is still valid by the time your code receives this event.
|
|
|
|
ZMQ_EVENT_ACCEPT_FAILED
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
The socket has rejected a connection from a remote peer. The event value is
|
|
the errno generated by the accept call.
|
|
|
|
ZMQ_EVENT_CLOSED
|
|
~~~~~~~~~~~~~~~~
|
|
The socket was closed. The event value is the FD of the (now closed) network
|
|
socket.
|
|
|
|
ZMQ_EVENT_CLOSE_FAILED
|
|
~~~~~~~~~~~~~~~~~~~~~~
|
|
The socket close failed. The event value is the errno returned by the system
|
|
call. Note that this event occurs only on IPC transports.
|
|
|
|
ZMQ_EVENT_DISCONNECTED
|
|
~~~~~~~~~~~~~~~~~~~~~~
|
|
The socket was disconnected unexpectedly. The event value is the FD of the
|
|
underlying network socket. Warning: this socket will be closed.
|
|
|
|
ZMQ_EVENT_MONITOR_STOPPED
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Monitoring on this socket ended.
|
|
|
|
|
|
RETURN VALUE
|
|
------------
|
|
The _zmq_socket_monitor()_ function returns a value of 0 or greater if
|
|
successful. Otherwise it returns `-1` and sets 'errno' to one of the values
|
|
defined below.
|
|
|
|
|
|
ERRORS
|
|
------
|
|
*ETERM*::
|
|
The 0MQ 'context' associated with the specified 'socket' was terminated.
|
|
|
|
*EPROTONOSUPPORT*::
|
|
The requested 'transport' protocol is not supported. Monitor sockets are
|
|
required to use the inproc:// transport.
|
|
|
|
*EINVAL*::
|
|
The endpoint supplied is invalid.
|
|
|
|
EXAMPLE
|
|
-------
|
|
.Monitoring client and server sockets
|
|
----
|
|
// Read one event off the monitor socket; return value and address
|
|
// by reference, if not null, and event number by value. Returns -1
|
|
// in case of error.
|
|
|
|
static int
|
|
get_monitor_event (void *monitor, int *value, char **address)
|
|
{
|
|
// First frame in message contains event number and value
|
|
zmq_msg_t msg;
|
|
zmq_msg_init (&msg);
|
|
if (zmq_msg_recv (&msg, monitor, 0) == -1)
|
|
return -1; // Interrupted, presumably
|
|
assert (zmq_msg_more (&msg));
|
|
|
|
uint8_t *data = (uint8_t *) zmq_msg_data (&msg);
|
|
uint16_t event = *(uint16_t *) (data);
|
|
if (value)
|
|
*value = *(uint32_t *) (data + 2);
|
|
|
|
// Second frame in message contains event address
|
|
zmq_msg_init (&msg);
|
|
if (zmq_msg_recv (&msg, monitor, 0) == -1)
|
|
return -1; // Interrupted, presumably
|
|
assert (!zmq_msg_more (&msg));
|
|
|
|
if (address) {
|
|
uint8_t *data = (uint8_t *) zmq_msg_data (&msg);
|
|
size_t size = zmq_msg_size (&msg);
|
|
*address = (char *) malloc (size + 1);
|
|
memcpy (*address, data, size);
|
|
*address [size] = 0;
|
|
}
|
|
return event;
|
|
}
|
|
|
|
int main (void)
|
|
{
|
|
void *ctx = zmq_ctx_new ();
|
|
assert (ctx);
|
|
|
|
// We'll monitor these two sockets
|
|
void *client = zmq_socket (ctx, ZMQ_DEALER);
|
|
assert (client);
|
|
void *server = zmq_socket (ctx, ZMQ_DEALER);
|
|
assert (server);
|
|
|
|
// Socket monitoring only works over inproc://
|
|
int rc = zmq_socket_monitor (client, "tcp://127.0.0.1:9999", 0);
|
|
assert (rc == -1);
|
|
assert (zmq_errno () == EPROTONOSUPPORT);
|
|
|
|
// Monitor all events on client and server sockets
|
|
rc = zmq_socket_monitor (client, "inproc://monitor-client", ZMQ_EVENT_ALL);
|
|
assert (rc == 0);
|
|
rc = zmq_socket_monitor (server, "inproc://monitor-server", ZMQ_EVENT_ALL);
|
|
assert (rc == 0);
|
|
|
|
// Create two sockets for collecting monitor events
|
|
void *client_mon = zmq_socket (ctx, ZMQ_PAIR);
|
|
assert (client_mon);
|
|
void *server_mon = zmq_socket (ctx, ZMQ_PAIR);
|
|
assert (server_mon);
|
|
|
|
// Connect these to the inproc endpoints so they'll get events
|
|
rc = zmq_connect (client_mon, "inproc://monitor-client");
|
|
assert (rc == 0);
|
|
rc = zmq_connect (server_mon, "inproc://monitor-server");
|
|
assert (rc == 0);
|
|
|
|
// Now do a basic ping test
|
|
rc = zmq_bind (server, "tcp://127.0.0.1:9998");
|
|
assert (rc == 0);
|
|
rc = zmq_connect (client, "tcp://127.0.0.1:9998");
|
|
assert (rc == 0);
|
|
bounce (client, server);
|
|
|
|
// Close client and server
|
|
close_zero_linger (client);
|
|
close_zero_linger (server);
|
|
|
|
// Now collect and check events from both sockets
|
|
int event = get_monitor_event (client_mon, NULL, NULL);
|
|
if (event == ZMQ_EVENT_CONNECT_DELAYED)
|
|
event = get_monitor_event (client_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_CONNECTED);
|
|
event = get_monitor_event (client_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_MONITOR_STOPPED);
|
|
|
|
// This is the flow of server events
|
|
event = get_monitor_event (server_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_LISTENING);
|
|
event = get_monitor_event (server_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_ACCEPTED);
|
|
event = get_monitor_event (server_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_CLOSED);
|
|
event = get_monitor_event (server_mon, NULL, NULL);
|
|
assert (event == ZMQ_EVENT_MONITOR_STOPPED);
|
|
|
|
// Close down the sockets
|
|
close_zero_linger (client_mon);
|
|
close_zero_linger (server_mon);
|
|
zmq_ctx_term (ctx);
|
|
|
|
return 0 ;
|
|
}
|
|
----
|
|
|
|
|
|
SEE ALSO
|
|
--------
|
|
linkzmq:zmq[7]
|
|
|
|
|
|
AUTHORS
|
|
-------
|
|
This page was written by the 0MQ community. To make a change please
|
|
read the 0MQ Contribution Policy at <http://www.zeromq.org/docs:contributing>.
|