| ZeroMQ(3pm) - phpMan
ZeroMQ(3pm) User Contributed Perl Documentation ZeroMQ(3pm)
NAME
ZeroMQ - A ZeroMQ2 wrapper for Perl (DEPRECATED)
SYNOPSIS ( HIGH-LEVEL API )
# echo server
use ZeroMQ qw/:all/;
my $cxt = ZeroMQ::Context->new;
my $sock = $cxt->socket(ZMQ_REP);
$sock->bind($addr);
my $msg;
foreach (1..$roundtrip_count) {
$msg = $sock->recv();
$sock->send($msg);
}
# json (if JSON.pm is available)
$sock->send_as( json => { foo => "bar" } );
my $thing = $sock->recv_as( "json" );
# custom serialization
ZeroMQ::register_read_type(myformat => sub { ... });
ZeroMQ::register_write_type(myformat => sub { .. });
$sock->send_as( myformat => $data ); # serialize using above callback
my $thing = $sock->recv_as( "myformat" );
SYNOPSIS ( LOW-LEVEL API )
use ZeroMQ::Raw;
my $ctxt = zmq_init($threads);
my $rv = zmq_term($ctxt);
my $msg = zmq_msg_init();
my $msg = zmq_msg_init_size( $size );
my $msg = zmq_msg_init_data( $data );
my $rv = zmq_msg_close( $msg );
my $rv = zmq_msg_move( $dest, $src );
my $rv = zmq_msg_copy( $dest, $src );
my $data = zmq_msg_data( $msg );
my $size = zmq_msg_size( $msg);
my $sock = zmq_socket( $ctxt, $type );
my $rv = zmq_close( $sock );
my $rv = zmq_setsockopt( $socket, $option, $value );
my $val = zmq_getsockopt( $socket, $option );
my $rv = zmq_bind( $sock, $addr );
my $rv = zmq_send( $sock, $msg, $flags );
my $msg = zmq_recv( $sock, $flags );
INSTALLATION
If you have libzmq registered with pkg-config:
perl Makefile.PL
make
make test
make install
If you don't have pkg-config, and libzmq is installed under /usr/local/libzmq:
ZMQ_HOME=/usr/local/libzmq \
perl Makefile.PL
make
make test
make install
If you want to customize include directories and such:
ZMQ_INCLUDES=/path/to/libzmq/include \
ZMQ_LIBS=/path/to/libzmq/lib \
ZMQ_H=/path/to/libzmq/include/zmq.h \
perl Makefile.PL
make
make test
make install
If you want to compile with debugging on:
perl Makefile.PL -g
DESCRIPTION
Please note that this module has been DEPRECATED in favor of ZMQ::LibZMQ2, ZMQ::LibZMQ3,
and ZMQ. see https://github.com/lestrrat/p5-ZMQ and other CPAN pages.
The "ZeroMQ" module is a wrapper of the 0MQ message passing library for Perl. It's a thin
wrapper around the C API. Please read <http://zeromq.org> for more details on ZeroMQ.
CLASS WALKTHROUGH
ZeroMQ::Raw
Use ZeroMQ::Raw to get access to the C API such as "zmq_init", "zmq_socket", et al.
Functions provided in this low level API should follow the C API exactly.
ZeroMQ::Constants
ZeroMQ::Constants contains all of the constants that are known to be extractable from
zmq.h. Do note that sometimes the list changes due to additions/deprecations in the
underlying zeromq2 library. We try to do our best to make things available (at least
to warn you that some symbols are deprecated), but it may not always be possible.
ZeroMQ::Context
ZeroMQ::Socket
ZeroMQ::Message
ZeroMQ::Context, ZeroMQ::Socket, ZeroMQ::Message contain the high-level, more perl-ish
interface to the zeromq functionalities.
ZeroMQ
Loading "ZeroMQ" will make the ZeroMQ::Context, ZeroMQ::Socket, and ZeroMQ::Message
classes available as well.
BASIC USAGE
To start using ZeroMQ, you need to create a context object, then as many ZeroMQ::Socket as
you need:
my $ctxt = ZeroMQ::Context->new;
my $socket = $ctxt->socket( ... options );
You need to call "bind()" or "connect()" on the socket, depending on your usage. For
example on a typical server-client model you would write on the server side:
$socket->bind( "tcp://127.0.0.1:9999" );
and on the client side:
$socket->connect( "tcp://127.0.0.1:9999" );
The underlying zeromq library offers TCP, multicast, in-process, and ipc connection
patterns. Read the zeromq manual for more details on other ways to setup the socket.
When sending data, you can either pass a ZeroMQ::Message object or a Perl string.
# the following two send() calls are equivalent
my $msg = ZeroMQ::Message->new( "a simple message" );
$socket->send( $msg );
$socket->send( "a simple message" );
In most cases using ZeroMQ::Message is redundunt, so you will most likely use the string
version.
To receive, simply call "recv()" on the socket
my $msg = $socket->recv;
The received message is an instance of ZeroMQ::Message object, and you can access the
content held in the message via the "data()" method:
my $data = $msg->data;
SERIALIZATION
ZeroMQ.pm comes with a simple serialization/deserialization mechanism.
To serialize, use "register_write_type()" to register a name and an associated callback to
serialize the data. For example, for JSON we do the following (this is already done for
you in ZeroMQ.pm if you have JSON.pm installed):
use JSON ();
ZeroMQ::register_write_type('json' => \&JSON::encode_json);
ZeroMQ::register_read_type('json' => \&JSON::decode_json);
Then you can use "send_as()" and "recv_as()" to specify the serialization type as the
first argument:
my $ctxt = ZeroMQ::Context->new();
my $sock = $ctxt->socket( ZMQ_REQ );
$sock->send_as( json => $complex_perl_data_structure );
The otherside will receive a JSON encoded data. The receivind side can be written as:
my $ctxt = ZeroMQ::Context->new();
my $sock = $ctxt->socket( ZMQ_REP );
my $complex_perl_data_structure = $sock->recv_as( 'json' );
If you have JSON.pm (must be 2.00 or above), then the JSON serializer / deserializer is
automatically enabled. If you want to tweak the serializer option, do something like this:
my $coder = JSON->new->utf8->pretty; # pretty print
ZeroMQ::register_write_type( json => sub { $coder->encode($_[0]) } );
ZeroMQ::register_read_type( json => sub { $coder->decode($_[0]) } );
Note that this will have a GLOBAL effect. If you want to change only your application, use
a name that's different from 'json'.
ASYNCHRONOUS I/O WITH ZEROMQ
By default ZeroMQ comes with its own zmq_poll() mechanism that can handle non-blocking
sockets. You can use this by calling zmq_poll with a list of hashrefs:
zmq_poll([
{
fd => fileno(STDOUT),
events => ZMQ_POLLOUT,
callback => \&callback,
},
{
socket => $zmq_socket,
events => ZMQ_POLLIN,
callback => \&callback
},
], $timeout );
Unfortunately this custom polling scheme doesn't play too well with AnyEvent.
As of zeromq2-2.1.0, you can use getsockopt to retrieve the underlying file descriptor, so
use that to integrate ZeroMQ and AnyEvent:
my $socket = zmq_socket( $ctxt, ZMQ_REP );
my $fh = zmq_getsockopt( $socket, ZMQ_FD );
my $w; $w = AE::io $fh, 0, sub {
while ( my $msg = zmq_recv( $socket, ZMQ_RCVMORE ) ) {
# do something with $msg;
}
undef $w;
};
NOTES ON MULTI-PROCESS and MULTI-THREADED USAGE
ZeroMQ works on both multi-process and multi-threaded use cases, but you need to be
careful bout sharing ZeroMQ objects.
For multi-process environments, you should not be sharing the context object. Create
separate contexts for each process, and therefore you shouldn't be sharing the socket
objects either.
For multi-thread environemnts, you can share the same context object. However you cannot
share sockets.
FUNCTIONS
version()
Returns the version of the underlying zeromq library that is being linked. In scalar
context, returns a dotted version string. In list context, returns a 3-element list of the
version numbers:
my $version_string = ZeroMQ::version();
my ($major, $minor, $patch) = ZeroMQ::version();
device($type, $sock1, $sock2)
register_read_type($name, \&callback)
Register a read callback for a given $name. This is used in "recv_as()". The callback
receives the data received from the socket.
register_write_type($name, \&callback)
Register a write callback for a given $name. This is used in "send_as()" The callback
receives the Perl structure given to "send_as()"
DEBUGGING XS
If you see segmentation faults, and such, you need to figure out where the error is
occuring in order for the maintainers to figure out what happened. Here's a very very
brief explanation of steps involved.
First, make sure to compile ZeroMQ.pm with debugging on by specifying -g:
perl Makefile.PL -g
make
Then fire gdb:
gdb perl
(gdb) R -Mblib /path/to/your/script.pl
When you see the crash, get a backtrace:
(gdb) bt
CAVEATS
This is an early release. Proceed with caution, please report (or better yet: fix) bugs
you encounter.
This module has been tested againt zeromq 2.1.4. Semantics of this module rely heavily on
the underlying zeromq version. Make sure you know which version of zeromq you're working
with.
SEE ALSO
ZeroMQ::Raw, ZeroMQ::Context, ZeroMQ::Socket, ZeroMQ::Message
<http://zeromq.org>
<http://github.com/lestrrat/ZeroMQ-Perl>
AUTHOR
Daisuke Maki "<daisuke AT endeworks.jp>"
Steffen Mueller, "<smueller AT cpan.org>"
COPYRIGHT AND LICENSE
The ZeroMQ module is
Copyright (C) 2010 by Daisuke Maki
This library is free software; you can redistribute it and/or modify it under the same
terms as Perl itself, either Perl version 5.8.0 or, at your option, any later version of
Perl 5 you may have available.
perl v5.20.0 2012-10-16 ZeroMQ(3pm)
|