NAME ZeroMQ - A ZeroMQ2 wrapper for Perl 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 ); DESCRIPTION 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 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 creating 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 $fh = zmq_getsockopt( $socket, ZMQ_FD ); my $w; $w = AE::io $fh, 0, sub { undef $w; print $fh "Hello\n"; }; 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()" CAVEATS This is an early release. Proceed with caution, please report (or better yet: fix) bugs you encounter. Tested againt 0MQ 2.1.0. SEE ALSO ZeroMQ::Context, ZeroMQ::Socket, ZeroMQ::Message AUTHOR Daisuke Maki "" Steffen Mueller, "" 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.