Starts one or more 0MQ devices. If you specify a DEVICE, FRONTEND, and BACKEND then _zmq_device_ starts a single device acting as a mini-broker. If you specify a CONFIGFILE, you can configure _zmq_device_ to start multiple concurrent devices with arbitrary configurations.
*Note* - zmq_deviced is not yet implemented. This is a design.
MINI-BROKER USAGE
-----------------
Runs as a mini-broker that accepts connects to both frontend and backend. This creates a hub-and-spoke topology in which all peers connect to the device. This is a robust and easy to manage topology.
DEVICE is one of: *queue*, *forwarder*, or *streamer*. See linkzmq:zmq_device[3] for a specification of these device types.
FRONTEND and BACKEND are endpoints in the format 'transport'`://`'address', See linkzmq:zmq_bind[3] for a specification of valid transports and addresses.
CONFIGURED USAGE
----------------
CONFIGFILE is the name of an XML file, readable by 'zmq_device'. This file provides a specification of the devices to start and how to connect and/or bind their frontends and backends. If CONFIGFILE is absent or *-* then the configuration is read from standard input.
The configuration file has this general syntax:
----
<?xml?>
<config [ iothreads="..." ] >
<device type="...">
<frontend [ type="..." ] >
<set name = "..." value = "..." />...
<bind endpoint="..." /> ...
<connect address="..." /> ...
</frontend>
<backend [ type="..." ] >
<set name = "..." value = "..." />...
<bind address="..." /> ...
<connect address="..." /> ...
</backend>
</device>
</config>
----
*iothreads*::
specifies the number of I/O threads for the process. Specify this only for high-volume scenarios. See linkzmq:zmq_init[3].
*device*::
defines one device. For each device element you define, 'zmq_device' will start a thread.
*frontend*::
defines the frontend for the device. Occurs once per device element. You may override the default socket type.
*backend*::
defines the backend for the device. Occurs once per device element. You may override the default socket type.
*set*::
defines a socket option for the frontend or backend. The valid names are *hwm*, *swap*, *identity*, *subscribe*, *unsubscribe*, *rate*, *recovery_ivl*, *mcast_loop*, *sndbuf*, and *rcvbuf*. See linkzmq:zmq_setsockopt[3].
*bind*::
binds the frontend or backend to the specified endpoint. See linkzmq:zmq_bind[3].
*connect*::
binds the frontend or backend to the specified endpoint. See linkzmq:zmq_connect[3].
SOCKET TYPES
------------
By default 'zmq_device' uses these socket types:
*queue* device::
frontend is *xrep*, backend is *xreq*.
*forwarder* device::
frontend is *sub*, backend is *pub*.
*streamer* device::
frontend is *pull*, backend is *push*.
You can override the socket type for frontend or backend. The valid types are: *req*, *rep*, *xreq*, *xrep*, *sub*, *pub*, *pull*, *push*, and *pair*. See linkzmq:zmq_socket[3].
*Note*: if you use a *sub* socket you must explicitly set a subscription filter or your socket will not receive any data.
