=head1 NAME AnyEvent::MP - multi-processing/message-passing framework =head1 SYNOPSIS use AnyEvent::MP; $NODE # contains this node's noderef NODE # returns this node's noderef NODE $port # returns the noderef of the port snd $port, type => data...; $SELF # receiving/own port id in rcv callbacks rcv $port, smartmatch => $cb->($port, @msg); # examples: rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; rcv $port1, pong => sub { warn "pong received\n" }; snd $port2, ping => $port1; # more, smarter, matches (_any_ is exported by this module) rcv $port, [child_died => $pid] => sub { ... rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 =head1 DESCRIPTION This module (-family) implements a simple message passing framework. Despite its simplicity, you can securely message other processes running on the same or other hosts. For an introduction to this module family, see the L manual page. At the moment, this module family is severly broken and underdocumented, so do not use. This was uploaded mainly to reserve the CPAN namespace - stay tuned! The basic API should be finished, however. =head1 CONCEPTS =over 4 =item port A port is something you can send messages to (with the C function). Some ports allow you to register C handlers that can match specific messages. All C handlers will receive messages they match, messages will not be queued. =item port id - C A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as separator, and a port name (a printable string of unspecified format). An exception is the the node port, whose ID is identical to it's node reference. =item node A node is a single process containing at least one port - the node port. You can send messages to node ports to find existing ports or to create new ports, among other things. Nodes are either private (single-process only), slaves (connected to a master node only) or public nodes (connectable from unrelated nodes). =item noderef - C, C, C A node reference is a string that either simply identifies the node (for private and slave nodes), or contains a recipe on how to reach a given node (for public nodes). This recipe is simply a comma-separated list of C pairs (for TCP/IP, other protocols might look different). Node references come in two flavours: resolved (containing only numerical addresses) or unresolved (where hostnames are used instead of addresses). Before using an unresolved node reference in a message you first have to resolve it. =back =head1 VARIABLES/FUNCTIONS =over 4 =cut package AnyEvent::MP; use AnyEvent::MP::Base; use common::sense; use Carp (); use AE (); use base "Exporter"; our $VERSION = '0.1'; our @EXPORT = qw( NODE $NODE *SELF node_of _any_ resolve_node become_slave become_public snd rcv mon kil reg psub port ); our $SELF; sub _self_die() { my $msg = $@; $msg =~ s/\n+$// unless ref $msg; kil $SELF, die => $msg; } =item $thisnode = NODE / $NODE The C function returns, and the C<$NODE> variable contains the noderef of the local node. The value is initialised by a call to C or C, after which all local port identifiers become invalid. =item $noderef = node_of $portid Extracts and returns the noderef from a portid or a noderef. =item $cv = resolve_node $noderef Takes an unresolved node reference that may contain hostnames and abbreviated IDs, resolves all of them and returns a resolved node reference. In addition to C pairs allowed in resolved noderefs, the following forms are supported: =over 4 =item the empty string An empty-string component gets resolved as if the default port (4040) was specified. =item naked port numbers (e.g. C<1234>) These are resolved by prepending the local nodename and a colon, to be further resolved. =item hostnames (e.g. C, C) These are resolved by using AnyEvent::DNS to resolve them, optionally looking up SRV records for the C port, if no port was specified. =back =item $SELF Contains the current port id while executing C callbacks or C blocks. =item SELF, %SELF, @SELF... Due to some quirks in how perl exports variables, it is impossible to just export C<$SELF>, all the symbols called C are exported by this module, but only C<$SELF> is currently used. =item snd $portid, type => @data =item snd $portid, @msg Send the given message to the given port ID, which can identify either a local or a remote port, and can be either a string or soemthignt hat stringifies a sa port ID (such as a port object :). While the message can be about anything, it is highly recommended to use a string as first element (a portid, or some word that indicates a request type etc.). The message data effectively becomes read-only after a call to this function: modifying any argument is not allowed and can cause many problems. The type of data you can transfer depends on the transport protocol: when JSON is used, then only strings, numbers and arrays and hashes consisting of those are allowed (no objects). When Storable is used, then anything that Storable can serialise and deserialise is allowed, and for the local node, anything can be passed. =item kil $portid[, @reason] Kill the specified port with the given C<@reason>. If no C<@reason> is specified, then the port is killed "normally" (linked ports will not be kileld, or even notified). Otherwise, linked ports get killed with the same reason (second form of C, see below). Runtime errors while evaluating C callbacks or inside C blocks will be reported as reason C<< die => $@ >>. Transport/communication errors are reported as C<< transport_error => $message >>. =item $guard = mon $portid, $cb->(@reason) =item $guard = mon $portid, $otherport =item $guard = mon $portid, $otherport, @msg Monitor the given port and do something when the port is killed. In the first form, the callback is simply called with any number of C<@reason> elements (no @reason means that the port was deleted "normally"). Note also that I<< the callback B never die >>, so use C if unsure. In the second form, the other port will be C'ed with C<@reason>, iff a @reason was specified, i.e. on "normal" kils nothing happens, while under all other conditions, the other port is killed with the same reason. In the last form, a message of the form C<@msg, @reason> will be C. Example: call a given callback when C<$port> is killed. mon $port, sub { warn "port died because of <@_>\n" }; Example: kill ourselves when C<$port> is killed abnormally. mon $port, $self; Example: send us a restart message another C<$port> is killed. mon $port, $self => "restart"; =cut sub mon { my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift); my $node = $NODE{$noderef} || add_node $noderef; #TODO: ports must not be references if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) { if (@_) { # send a kill info message my (@msg) = ($cb, @_); $cb = sub { snd @msg, @_ }; } else { # simply kill other port my $port = $cb; $cb = sub { kil $port, @_ if @_ }; } } $node->monitor ($port, $cb); defined wantarray and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } } =item $guard = mon_guard $port, $ref, $ref... Monitors the given C<$port> and keeps the passed references. When the port is killed, the references will be freed. Optionally returns a guard that will stop the monitoring. This function is useful when you create e.g. timers or other watchers and want to free them when the port gets killed: $port->rcv (start => sub { my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { undef $timer if 0.9 < rand; }); }); =cut sub mon_guard { my ($port, @refs) = @_; mon $port, sub { 0 && @refs } } =item lnk $port1, $port2 Link two ports. This is simply a shorthand for: mon $port1, $port2; mon $port2, $port1; It means that if either one is killed abnormally, the other one gets killed as well. =item $local_port = port Create a new local port object that supports message matching. =item $portid = port { my @msg = @_; $finished } Creates a "mini port", that is, a very lightweight port without any pattern matching behind it, and returns its ID. The block will be called for every message received on the port. When the callback returns a true value its job is considered "done" and the port will be destroyed. Otherwise it will stay alive. The message will be passed as-is, no extra argument (i.e. no port id) will be passed to the callback. If you need the local port id in the callback, this works nicely: my $port; $port = miniport { snd $otherport, reply => $port; }; =cut sub port(;&) { my $id = "$UNIQ." . $ID++; my $port = "$NODE#$id"; if (@_) { my $cb = shift; $PORT{$id} = sub { local $SELF = $port; eval { &$cb and kil $id; }; _self_die if $@; }; } else { my $self = bless { id => "$NODE#$id", }, "AnyEvent::MP::Port"; $PORT_DATA{$id} = $self; $PORT{$id} = sub { local $SELF = $port; eval { for (@{ $self->{rc0}{$_[0]} }) { $_ && &{$_->[0]} && undef $_; } for (@{ $self->{rcv}{$_[0]} }) { $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1] && &{$_->[0]} && undef $_; } for (@{ $self->{any} }) { $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1] && &{$_->[0]} && undef $_; } }; _self_die if $@; }; } $port } =item reg $portid, $name Registers the given port under the name C<$name>. If the name already exists it is replaced. A port can only be registered under one well known name. A port automatically becomes unregistered when it is killed. =cut sub reg(@) { my ($portid, $name) = @_; $REG{$name} = $portid; } =item rcv $portid, tagstring => $callback->(@msg), ... =item rcv $portid, $smartmatch => $callback->(@msg), ... =item rcv $portid, [$smartmatch...] => $callback->(@msg), ... Register callbacks to be called on matching messages on the given port. The callback has to return a true value when its work is done, after which is will be removed, or a false value in which case it will stay registered. The global C<$SELF> (exported by this module) contains C<$portid> while executing the callback. Runtime errors wdurign callback execution will result in the port being Ced. If the match is an array reference, then it will be matched against the first elements of the message, otherwise only the first element is being matched. Any element in the match that is specified as C<_any_> (a function exported by this module) matches any single element of the message. While not required, it is highly recommended that the first matching element is a string identifying the message. The one-string-only match is also the most efficient match (by far). =cut sub rcv($@) { my ($noderef, $port) = split /#/, shift, 2; ($NODE{$noderef} || add_node $noderef) == $NODE{""} or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught"; my $self = $PORT_DATA{$port} or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught"; "AnyEvent::MP::Port" eq ref $self or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught"; while (@_) { my ($match, $cb) = splice @_, 0, 2; if (!ref $match) { push @{ $self->{rc0}{$match} }, [$cb]; } elsif (("ARRAY" eq ref $match && !ref $match->[0])) { my ($type, @match) = @$match; @match ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match] : push @{ $self->{rc0}{$match->[0]} }, [$cb]; } else { push @{ $self->{any} }, [$cb, $match]; } } } =item $closure = psub { BLOCK } Remembers C<$SELF> and creates a closure out of the BLOCK. When the closure is executed, sets up the environment in the same way as in C callbacks, i.e. runtime errors will cause the port to get Ced. This is useful when you register callbacks from C callbacks: rcv delayed_reply => sub { my ($delay, @reply) = @_; my $timer = AE::timer $delay, 0, psub { snd @reply, $SELF; }; }; =cut sub psub(&) { my $cb = shift; my $port = $SELF or Carp::croak "psub can only be called from within rcv or psub callbacks, not"; sub { local $SELF = $port; if (wantarray) { my @res = eval { &$cb }; _self_die if $@; @res } else { my $res = eval { &$cb }; _self_die if $@; $res } } } =back =head1 FUNCTIONS FOR NODES =over 4 =item become_public $noderef Tells the node to become a public node, i.e. reachable from other nodes. The first argument is the (unresolved) node reference of the local node (if missing then the empty string is used). It is quite common to not specify anything, in which case the local node tries to listen on the default port, or to only specify a port number, in which case AnyEvent::MP tries to guess the local addresses. =cut =back =head1 NODE MESSAGES Nodes understand the following messages sent to them. Many of them take arguments called C<@reply>, which will simply be used to compose a reply message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and the remaining arguments are simply the message data. While other messages exist, they are not public and subject to change. =over 4 =cut =item lookup => $name, @reply Replies with the port ID of the specified well-known port, or C. =item devnull => ... Generic data sink/CPU heat conversion. =item relay => $port, @msg Simply forwards the message to the given port. =item eval => $string[ @reply] Evaluates the given string. If C<@reply> is given, then a message of the form C<@reply, $@, @evalres> is sent. Example: crash another node. snd $othernode, eval => "exit"; =item time => @reply Replies the the current node time to C<@reply>. Example: tell the current node to send the current time to C<$myport> in a C message. snd $NODE, time => $myport, timereply => 1, 2; # => snd $myport, timereply => 1, 2,