You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
4.4 KiB
89 lines
4.4 KiB
'\" t
|
|
.\" Title: zmq_proxy
|
|
.\" Author: [see the "AUTHORS" section]
|
|
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
|
|
.\" Date: 09/14/2016
|
|
.\" Manual: 0MQ Manual
|
|
.\" Source: 0MQ 4.1.5
|
|
.\" Language: English
|
|
.\"
|
|
.TH "ZMQ_PROXY" "3" "09/14/2016" "0MQ 4\&.1\&.5" "0MQ Manual"
|
|
.\" -----------------------------------------------------------------
|
|
.\" * Define some portability stuff
|
|
.\" -----------------------------------------------------------------
|
|
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
.\" http://bugs.debian.org/507673
|
|
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
|
|
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
.ie \n(.g .ds Aq \(aq
|
|
.el .ds Aq '
|
|
.\" -----------------------------------------------------------------
|
|
.\" * set default formatting
|
|
.\" -----------------------------------------------------------------
|
|
.\" disable hyphenation
|
|
.nh
|
|
.\" disable justification (adjust text to left margin only)
|
|
.ad l
|
|
.\" -----------------------------------------------------------------
|
|
.\" * MAIN CONTENT STARTS HERE *
|
|
.\" -----------------------------------------------------------------
|
|
.SH "NAME"
|
|
zmq_proxy \- start built\-in 0MQ proxy
|
|
.SH "SYNOPSIS"
|
|
.sp
|
|
\fBint zmq_proxy (const void \fR\fB\fI*frontend\fR\fR\fB, const void \fR\fB\fI*backend\fR\fR\fB, const void \fR\fB\fI*capture\fR\fR\fB);\fR
|
|
.SH "DESCRIPTION"
|
|
.sp
|
|
The \fIzmq_proxy()\fR function starts the built\-in 0MQ proxy in the current application thread\&.
|
|
.sp
|
|
The proxy connects a frontend socket to a backend socket\&. Conceptually, data flows from frontend to backend\&. Depending on the socket types, replies may flow in the opposite direction\&. The direction is conceptual only; the proxy is fully symmetric and there is no technical difference between frontend and backend\&.
|
|
.sp
|
|
Before calling \fIzmq_proxy()\fR you must set any socket options, and connect or bind both frontend and backend sockets\&. The two conventional proxy models are:
|
|
.sp
|
|
\fIzmq_proxy()\fR runs in the current thread and returns only if/when the current context is closed\&.
|
|
.sp
|
|
If the capture socket is not NULL, the proxy shall send all messages, received on both frontend and backend, to the capture socket\&. The capture socket should be a \fIZMQ_PUB\fR, \fIZMQ_DEALER\fR, \fIZMQ_PUSH\fR, or \fIZMQ_PAIR\fR socket\&.
|
|
.sp
|
|
Refer to \fBzmq_socket\fR(3) for a description of the available socket types\&.
|
|
.SH "EXAMPLE USAGE"
|
|
.SS "Shared Queue"
|
|
.sp
|
|
When the frontend is a ZMQ_ROUTER socket, and the backend is a ZMQ_DEALER socket, the proxy shall act as a shared queue that collects requests from a set of clients, and distributes these fairly among a set of services\&. Requests shall be fair\-queued from frontend connections and distributed evenly across backend connections\&. Replies shall automatically return to the client that made the original request\&.
|
|
.SS "Forwarder"
|
|
.sp
|
|
When the frontend is a ZMQ_XSUB socket, and the backend is a ZMQ_XPUB socket, the proxy shall act as a message forwarder that collects messages from a set of publishers and forwards these to a set of subscribers\&. This may be used to bridge networks transports, e\&.g\&. read on tcp:// and forward on pgm://\&.
|
|
.SS "Streamer"
|
|
.sp
|
|
When the frontend is a ZMQ_PULL socket, and the backend is a ZMQ_PUSH socket, the proxy shall collect tasks from a set of clients and forwards these to a set of workers using the pipeline pattern\&.
|
|
.SH "RETURN VALUE"
|
|
.sp
|
|
The \fIzmq_proxy()\fR function always returns \-1 and \fIerrno\fR set to \fBETERM\fR (the 0MQ \fIcontext\fR associated with either of the specified sockets was terminated)\&.
|
|
.SH "EXAMPLE"
|
|
.PP
|
|
\fBCreating a shared queue proxy\fR.
|
|
.sp
|
|
.if n \{\
|
|
.RS 4
|
|
.\}
|
|
.nf
|
|
// Create frontend and backend sockets
|
|
void *frontend = zmq_socket (context, ZMQ_ROUTER);
|
|
assert (backend);
|
|
void *backend = zmq_socket (context, ZMQ_DEALER);
|
|
assert (frontend);
|
|
// Bind both sockets to TCP ports
|
|
assert (zmq_bind (frontend, "tcp://*:5555") == 0);
|
|
assert (zmq_bind (backend, "tcp://*:5556") == 0);
|
|
// Start the queue proxy, which runs until ETERM
|
|
zmq_proxy (frontend, backend, NULL);
|
|
.fi
|
|
.if n \{\
|
|
.RE
|
|
.\}
|
|
.sp
|
|
.SH "SEE ALSO"
|
|
.sp
|
|
\fBzmq_bind\fR(3) \fBzmq_connect\fR(3) \fBzmq_socket\fR(3) \fBzmq\fR(7)
|
|
.SH "AUTHORS"
|
|
.sp
|
|
This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.
|
|
|