--- AnyEvent-MP/MP.pm 2009/08/01 07:44:02 1.5 +++ AnyEvent-MP/MP.pm 2009/09/03 07:57:30 1.77 @@ -6,28 +6,56 @@ use AnyEvent::MP; - NODE # returns this node identifier - $NODE # contains this node identifier + $NODE # contains this node's node ID + NODE # returns this node's node ID + $SELF # receiving/own port id in rcv callbacks + + # initialise the node so it can send/receive messages + configure; + + # ports are message destinations + + # sending messages snd $port, type => data...; + snd $port, @msg; + snd @msg_with_first_element_being_a_port; - rcv $port, smartmatch => $cb->($port, @msg); + # creating/using ports, the simple way + my $simple_port = port { my @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 + # creating/using ports, tagged message matching + my $port = port; + rcv $port, ping => sub { snd $_[0], "pong" }; + rcv $port, pong => sub { warn "pong received\n" }; + + # create a port on another node + my $port = spawn $node, $initfunc, @initdata; + + # monitoring + mon $port, $cb->(@msg) # callback is invoked on death + mon $port, $otherport # kill otherport on abnormal death + mon $port, $otherport, @msg # send message on death + +=head1 CURRENT STATUS + + bin/aemp - stable. + AnyEvent::MP - stable API, should work. + AnyEvent::MP::Intro - explains most concepts. + AnyEvent::MP::Kernel - mostly stable. + AnyEvent::MP::Global - stable API, protocol not yet final. + + stay tuned. =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. +on the same or other hosts, and you can supervise entities remotely. + +For an introduction to this module family, see the L +manual page and the examples under F. =head1 CONCEPTS @@ -35,30 +63,55 @@ =item port -A port is something you can send messages to with the C function, and -you can register C handlers with. All C handlers will receive -messages they match, messages will not be queued. +A port is something you can send messages to (with the C function). -=item port id - C +Ports allow you to register C handlers that can match all or just +some messages. Messages send to ports will not be queued, regardless of +anything was listening for them or not. -A port id is always the noderef, a hash-mark (C<#>) as separator, followed -by a port name (a printable string of unspecified format). +=item port ID - C + +A port ID is the concatenation of a node ID, a hash-mark (C<#>) as +separator, and a port name (a printable string of unspecified format). =item node -A node is a single process containing at least one port - the node -port. You can send messages to node ports to let them create new ports, -among other things. - -Initially, nodes are either private (single-process only) or hidden -(connected to a master node only). Only when they epxlicitly "become -public" can you send them messages from unrelated other nodes. - -=item noderef - C, C, C - -A noderef is a string that either uniquely identifies a given node (for -private and hidden nodes), or contains a recipe on how to reach a given -node (for public nodes). +A node is a single process containing at least one port - the node port, +which enables nodes to manage each other remotely, and to create new +ports. + +Nodes are either public (have one or more listening ports) or private +(no listening ports). Private nodes cannot talk to other private nodes +currently. + +=item node ID - C<[a-za-Z0-9_\-.:]+> + +A node ID is a string that uniquely identifies the node within a +network. Depending on the configuration used, node IDs can look like a +hostname, a hostname and a port, or a random string. AnyEvent::MP itself +doesn't interpret node IDs in any way. + +=item binds - C + +Nodes can only talk to each other by creating some kind of connection to +each other. To do this, nodes should listen on one or more local transport +endpoints - binds. Currently, only standard C specifications can +be used, which specify TCP ports to listen on. + +=item seeds - C + +When a node starts, it knows nothing about the network. To teach the node +about the network it first has to contact some other node within the +network. This node is called a seed. + +Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes +are expected to be long-running, and at least one of those should always +be available. When nodes run out of connections (e.g. due to a network +error), they try to re-establish connections to some seednodes again to +join the network. + +Apart from being sued for seeding, seednodes are not special in any way - +every public node can be a seednode. =back @@ -70,11 +123,8 @@ package AnyEvent::MP; -use AnyEvent::MP::Util (); -use AnyEvent::MP::Node; -use AnyEvent::MP::Transport; +use AnyEvent::MP::Kernel; -use utf8; use common::sense; use Carp (); @@ -83,360 +133,719 @@ use base "Exporter"; -our $VERSION = '0.0'; -our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_); +our $VERSION = $AnyEvent::MP::Kernel::VERSION; -our $DEFAULT_SECRET; -our $DEFAULT_PORT = "4040"; +our @EXPORT = qw( + NODE $NODE *SELF node_of after + configure + snd rcv mon mon_guard kil reg psub spawn + port +); + +our $SELF; + +sub _self_die() { + my $msg = $@; + $msg =~ s/\n+$// unless ref $msg; + kil $SELF, die => $msg; +} -our $CONNECT_INTERVAL = 5; # new connect every 5s, at least -our $CONNECT_TIMEOUT = 30; # includes handshake +=item $thisnode = NODE / $NODE -sub default_secret { - unless (defined $DEFAULT_SECRET) { - if (open my $fh, "<$ENV{HOME}/.aemp-secret") { - sysread $fh, $DEFAULT_SECRET, -s $fh; - } else { - $DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32; - } - } +The C function returns, and the C<$NODE> variable contains, the node +ID of the node running in the current process. This value is initialised by +a call to C. - $DEFAULT_SECRET -} +=item $nodeid = node_of $port -=item NODE / $NODE +Extracts and returns the node ID from a port ID or a node ID. -The C function and the C<$NODE> variable contain 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 configure key => value... -=cut +Before a node can talk to other nodes on the network (i.e. enter +"distributed mode") it has to configure itself - the minimum a node needs +to know is its own name, and optionally it should know the addresses of +some other nodes in the network to discover other nodes. -our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie -our $PUBLIC = 0; -our $NODE; -our $PORT; - -our %NODE; # node id to transport mapping, or "undef", for local node -our %PORT; # local ports -our %LISTENER; # local transports - -sub NODE() { $NODE } - -{ - use POSIX (); - my $nodename = (POSIX::uname)[1]; - $NODE = "$$\@$nodename"; -} +This function configures a node - it must be called exactly once (or +never) before calling other AnyEvent::MP functions. + +=over 4 -sub _ANY_() { 1 } -sub _any_() { \&_ANY_ } +=item step 1, gathering configuration from profiles -sub add_node { - my ($noderef) = @_; +The function first looks up a profile in the aemp configuration (see the +L commandline utility). The profile name can be specified via the +named C parameter. If it is missing, then the nodename (F) will be used as profile name. + +The profile data is then gathered as follows: + +First, all remaining key => value pairs (all of which are conveniently +undocumented at the moment) will be interpreted as configuration +data. Then they will be overwritten by any values specified in the global +default configuration (see the F utility), then the chain of +profiles chosen by the profile name (and any C attributes). + +That means that the values specified in the profile have highest priority +and the values specified directly via C have lowest priority, +and can only be used to specify defaults. + +If the profile specifies a node ID, then this will become the node ID of +this process. If not, then the profile name will be used as node ID. The +special node ID of C will be replaced by a random node ID. + +=item step 2, bind listener sockets + +The next step is to look up the binds in the profile, followed by binding +aemp protocol listeners on all binds specified (it is possible and valid +to have no binds, meaning that the node cannot be contacted form the +outside. This means the node cannot talk to other nodes that also have no +binds, but it can still talk to all "normal" nodes). + +If the profile does not specify a binds list, then a default of C<*> is +used, meaning the node will bind on a dynamically-assigned port on every +local IP address it finds. + +=item step 3, connect to seed nodes + +As the last step, the seeds list from the profile is passed to the +L module, which will then use it to keep +connectivity with at least one node at any point in time. - return $NODE{$noderef} - if exists $NODE{$noderef}; +=back - for (split /,/, $noderef) { - return $NODE{$noderef} = $NODE{$_} - if exists $NODE{$_}; - } +Example: become a distributed node using the locla node name as profile. +This should be the most common form of invocation for "daemon"-type nodes. - # for indirect sends, use a different class - my $node = new AnyEvent::MP::Node::Direct $noderef; + configure - $NODE{$_} = $node - for $noderef, split /,/, $noderef; +Example: become an anonymous node. This form is often used for commandline +clients. - $node -} + configure nodeid => "anon/"; + +Example: configure a node using a profile called seed, which si suitable +for a seed node as it binds on all local addresses on a fixed port (4040, +customary for aemp). -=item snd $portid, type => @data + # use the aemp commandline utility + # aemp profile seed nodeid anon/ binds '*:4040' -=item snd $portid, @msg + # then use it + configure profile => "seed"; -Send the given message to the given port ID, which can identify either a -local or a remote port. + # or simply use aemp from the shell again: + # aemp run profile seed -While the message can be about anything, it is highly recommended to use -a constant string as first element. + # or provide a nicer-to-remember nodeid + # aemp run profile seed nodeid "$(hostname)" -The message data effectively becomes read-only after a call to this -function: modifying any argument is not allowed and can cause many -problems. +=item $SELF + +Contains the current port id while executing C callbacks or C +blocks. + +=item *SELF, SELF, %SELF, @SELF... + +Due to some quirks in how perl exports variables, it is impossible to +just export C<$SELF>, all the symbols named C are exported by this +module, but only C<$SELF> is currently used. + +=item snd $port, type => @data + +=item snd $port, @msg + +Send the given message to the given port, which can identify either a +local or a remote port, and must be a port ID. + +While the message can be almost anything, it is highly recommended to +use a string as first element (a port ID, or some word that indicates a +request type etc.) and to consist if only simple perl values (scalars, +arrays, hashes) - if you think you need to pass an object, think again. + +The message data logically becomes read-only after a call to this +function: modifying any argument (or values referenced by them) is +forbidden, as there can be considerable time between the call to C +and the time the message is actually being serialised - in fact, it might +never be copied as within the same process it is simply handed to the +receiving port. 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. +node, anything can be passed. Best rely only on the common denominator of +these. + +=item $local_port = port + +Create a new local port object and returns its port ID. Initially it has +no callbacks set and will throw an error when it receives messages. + +=item $local_port = port { my @msg = @_ } + +Creates a new local port, and returns its ID. Semantically the same as +creating a port and calling C on it. + +The block will be called for every message received on the port, with the +global variable C<$SELF> set to the port ID. Runtime errors will cause the +port to be Ced. The message will be passed as-is, no extra argument +(i.e. no port ID) will be passed to the callback. + +If you want to stop/destroy the port, simply C it: + + my $port = port { + my @msg = @_; + ... + kil $SELF; + }; =cut -sub snd(@) { - my ($noderef, $port) = split /#/, shift, 2; +sub rcv($@); + +sub _kilme { + die "received message on port without callback"; +} + +sub port(;&) { + my $id = "$UNIQ." . $ID++; + my $port = "$NODE#$id"; - add_node $noderef - unless exists $NODE{$noderef}; + rcv $port, shift || \&_kilme; - $NODE{$noderef}->send (["$port", [@_]]); + $port } -=item rcv $portid, type => $callback->(@msg) +=item rcv $local_port, $callback->(@msg) -=item rcv $portid, $smartmatch => $callback->(@msg) +Replaces the default callback on the specified port. There is no way to +remove the default callback: use C to disable it, or better +C the port when it is no longer needed. -=item rcv $portid, [$smartmatch...] => $callback->(@msg) +The global C<$SELF> (exported by this module) contains C<$port> while +executing the callback. Runtime errors during callback execution will +result in the port being Ced. -Register a callback on the port identified by C<$portid>, which I be -a local port. +The default callback received all messages not matched by a more specific +C match. -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. +=item rcv $local_port, tag => $callback->(@msg_without_tag), ... -If the match is an array reference, then it will be matched against the -first elements of the message, otherwise only the first element is being -matched. +Register (or replace) callbacks to be called on messages starting with the +given tag on the given port (and return the port), or unregister it (when +C<$callback> is C<$undef> or missing). There can only be one callback +registered for each tag. -Any element in the match that is specified as C<_any_> (a function -exported by this module) matches any single element of the message. +The original message will be passed to the callback, after the first +element (the tag) has been removed. The callback will use the same +environment as the default callback (see above). -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). +Example: create a port and bind receivers on it in one go. + + my $port = rcv port, + msg1 => sub { ... }, + msg2 => sub { ... }, + ; + +Example: create a port, bind receivers and send it in a message elsewhere +in one go: + + snd $otherport, reply => + rcv port, + msg1 => sub { ... }, + ... + ; + +Example: temporarily register a rcv callback for a tag matching some port +(e.g. for a rpc reply) and unregister it after a message was received. + + rcv $port, $otherport => sub { + my @reply = @_; + + rcv $SELF, $otherport; + }; =cut sub rcv($@) { - my ($port, $match, $cb) = @_; + my $port = shift; + my ($nodeid, $portid) = split /#/, $port, 2; - my $port = $PORT{$port} - or do { - my ($noderef, $lport) = split /#/, $port; - "AnyEvent::MP::Node::Self" eq ref $NODE{$noderef} - or Carp::croak "$port: can only rcv on local ports"; - - $PORT{$lport} - or Carp::croak "$port: port does not exist"; - - $PORT{$port} = $PORT{$lport} # also return - }; + $NODE{$nodeid} == $NODE{""} + or Carp::croak "$port: rcv can only be called on local ports, caught"; + + while (@_) { + if (ref $_[0]) { + if (my $self = $PORT_DATA{$portid}) { + "AnyEvent::MP::Port" eq ref $self + or Carp::croak "$port: rcv can only be called on message matching ports, caught"; + + $self->[2] = shift; + } else { + my $cb = shift; + $PORT{$portid} = sub { + local $SELF = $port; + eval { &$cb }; _self_die if $@; + }; + } + } elsif (defined $_[0]) { + my $self = $PORT_DATA{$portid} ||= do { + my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; + + $PORT{$portid} = sub { + local $SELF = $port; + + if (my $cb = $self->[1]{$_[0]}) { + shift; + eval { &$cb }; _self_die if $@; + } else { + &{ $self->[0] }; + } + }; - if (!ref $match) { - push @{ $port->{rc0}{$match} }, [$cb]; - } elsif (("ARRAY" eq ref $match && !ref $match->[0])) { - my ($type, @match) = @$match; - @match - ? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match] - : push @{ $port->{rc0}{$match->[0]} }, [$cb]; - } else { - push @{ $port->{any} }, [$cb, $match]; + $self + }; + + "AnyEvent::MP::Port" eq ref $self + or Carp::croak "$port: rcv can only be called on message matching ports, caught"; + + my ($tag, $cb) = splice @_, 0, 2; + + if (defined $cb) { + $self->[1]{$tag} = $cb; + } else { + delete $self->[1]{$tag}; + } + } } + + $port } -sub _inject { - my ($port, $msg) = @{+shift}; +=item $closure = psub { BLOCK } - $port = $PORT{$port} - or return; +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, $SELF; + }; + }; - @_ = @$msg; +=cut - for (@{ $port->{rc0}{$msg->[0]} }) { - $_ && &{$_->[0]} - && undef $_; - } +sub psub(&) { + my $cb = shift; - for (@{ $port->{rcv}{$msg->[0]} }) { - $_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1] - && &{$_->[0]} - && undef $_; - } + my $port = $SELF + or Carp::croak "psub can only be called from within rcv or psub callbacks, not"; + + sub { + local $SELF = $port; - for (@{ $port->{any} }) { - $_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1] - && &{$_->[0]} - && undef $_; + if (wantarray) { + my @res = eval { &$cb }; + _self_die if $@; + @res + } else { + my $res = eval { &$cb }; + _self_die if $@; + $res + } } } -sub normalise_noderef($) { - my ($noderef) = @_; +=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies - my $cv = AE::cv; - my @res; +=item $guard = mon $port, $rcvport # kill $rcvport when $port dies - $cv->begin (sub { - my %seen; - my @refs; - for (sort { $a->[0] <=> $b->[0] } @res) { - push @refs, $_->[1] unless $seen{$_->[1]}++ - } - shift->send (join ",", @refs); - }); +=item $guard = mon $port # kill $SELF when $port dies - $noderef = $DEFAULT_PORT unless length $noderef; +=item $guard = mon $port, $rcvport, @msg # send a message when $port dies - my $idx; - for my $t (split /,/, $noderef) { - my $pri = ++$idx; - - #TODO: this should be outside normalise_noderef and in become_public - if ($t =~ /^\d*$/) { - my $nodename = (POSIX::uname)[1]; - - $cv->begin; - AnyEvent::Socket::resolve_sockaddr $nodename, $t || "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub { - for (@_) { - my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3]; - push @res, [ - $pri += 1e-5, - AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service - ]; - } - $cv->end; - }; +Monitor the given port and do something when the port is killed or +messages to it were lost, and optionally return a guard that can be used +to stop monitoring again. -# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename; -# -# for (@ipv4) { -# push @res, [ -# $pri, -# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t || $DEFAULT_PORT, -# ]; -# } - } else { - my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT" - or Carp::croak "$t: unparsable transport descriptor"; +C effectively guarantees that, in the absence of hardware failures, +after starting the monitor, either all messages sent to the port will +arrive, or the monitoring action will be invoked after possible message +loss has been detected. No messages will be lost "in between" (after +the first lost message no further messages will be received by the +port). After the monitoring action was invoked, further messages might get +delivered again. - $cv->begin; - AnyEvent::Socket::resolve_sockaddr $host, $port, "tcp", 0, undef, sub { - for (@_) { - my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3]; - push @res, [ - $pri += 1e-5, - AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service - ]; - } - $cv->end; - } +Note that monitoring-actions are one-shot: once messages are lost (and a +monitoring alert was raised), they are removed and will not trigger again. + +In the first form (callback), the callback is simply called with any +number of C<@reason> elements (no @reason means that the port was deleted +"normally"). Note also that I<< the callback B never die >>, so use +C if unsure. + +In the second form (another port given), the other port (C<$rcvport>) +will be C'ed with C<@reason>, if 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. + +The third form (kill self) is the same as the second form, except that +C<$rvport> defaults to C<$SELF>. + +In the last form (message), a message of the form C<@msg, @reason> will be +C. + +As a rule of thumb, monitoring requests should always monitor a port from +a local port (or callback). The reason is that kill messages might get +lost, just like any other message. Another less obvious reason is that +even monitoring requests can get lost (for example, when the connection +to the other node goes down permanently). When monitoring a port locally +these problems do not exist. + +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 $port; + +Example: send us a restart message when another C<$port> is killed. + + mon $port, $self => "restart"; + +=cut + +sub mon { + my ($nodeid, $port) = split /#/, shift, 2; + + my $node = $NODE{$nodeid} || add_node $nodeid; + + my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; + + unless (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 @_ }; } } - $cv->end; + $node->monitor ($port, $cb); - $cv + defined wantarray + and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } } -sub become_public { - return if $PUBLIC; +=item $guard = mon_guard $port, $ref, $ref... - my $noderef = join ",", ref $_[0] ? @{+shift} : shift; - my @args = @_; +Monitors the given C<$port> and keeps the passed references. When the port +is killed, the references will be freed. - $NODE = (normalise_noderef $noderef)->recv; +Optionally returns a guard that will stop the monitoring. - for my $t (split /,/, $NODE) { - $NODE{$t} = $NODE{""}; - - my ($host, $port) = AnyEvent::Socket::parse_hostport $t; - - $LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port, - @args, - on_error => sub { - die "on_error<@_>\n";#d# - }, - on_connect => sub { - my ($tp) = @_; - - $NODE{$tp->{remote_id}} = $_[0]; - }, - sub { - my ($tp) = @_; - - $NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp; - }, - ; - } +This function is useful when you create e.g. timers or other watchers and +want to free them when the port gets killed (note the use of C): + + $port->rcv (start => sub { + my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub { + undef $timer if 0.9 < rand; + }); + }); - $PUBLIC = 1; +=cut + +sub mon_guard { + my ($port, @refs) = @_; + + #TODO: mon-less form? + + mon $port, sub { 0 && @refs } } -=back +=item kil $port[, @reason] -=head1 NODE MESSAGES +Kill the specified port with the given C<@reason>. -Nodes understand the following messages sent to them. Many of them take -arguments called C<@reply>, which will simply be used to compose a reply -message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and -the remaining arguments are simply the message data. +If no C<@reason> is specified, then the port is killed "normally" (ports +monitoring other ports will not necessarily die because a port dies +"normally"). -=over 4 +Otherwise, linked ports get killed with the same reason (second form of +C, see above). + +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 >>. =cut -############################################################################# -# self node code +=item $port = spawn $node, $initfunc[, @initdata] + +Creates a port on the node C<$node> (which can also be a port ID, in which +case it's the node where that port resides). + +The port ID of the newly created port is returned immediately, and it is +possible to immediately start sending messages or to monitor the port. -sub _new_port($) { - my ($name) = @_; +After the port has been created, the init function is called on the remote +node, in the same context as a C callback. This function must be a +fully-qualified function name (e.g. C). To +specify a function in the main program, use C<::name>. - my ($noderef, $portname) = split /#/, $name; +If the function doesn't exist, then the node tries to C +the package, then the package above the package and so on (e.g. +C, C, C) until the function +exists or it runs out of package names. - $PORT{$name} = - $PORT{$portname} = { - names => [$name, $portname], +The init function is then called with the newly-created port as context +object (C<$SELF>) and the C<@initdata> values as arguments. + +A common idiom is to pass a local port, immediately monitor the spawned +port, and in the remote init function, immediately monitor the passed +local port. This two-way monitoring ensures that both ports get cleaned up +when there is a problem. + +Example: spawn a chat server port on C<$othernode>. + + # this node, executed from within a port context: + my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; + mon $server; + + # init function on C<$othernode> + sub connect { + my ($srcport) = @_; + + mon $srcport; + + rcv $SELF, sub { + ... + }; + } + +=cut + +sub _spawn { + my $port = shift; + my $init = shift; + + local $SELF = "$NODE#$port"; + eval { + &{ load_func $init } }; + _self_die if $@; } -$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE; -_new_port ""; +sub spawn(@) { + my ($nodeid, undef) = split /#/, shift, 2; -=item relay => $port, @msg + my $id = "$RUNIQ." . $ID++; -Simply forwards the message to the given port. + $_[0] =~ /::/ + or Carp::croak "spawn init function must be a fully-qualified name, caught"; -=cut + snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_; -rcv "", relay => \&snd; + "$nodeid#$id" +} -=item eval => $string[ @reply] +=item after $timeout, @msg -Evaluates the given string. If C<@reply> is given, then a message of the -form C<@reply, $@, @evalres> is sent. +=item after $timeout, $callback -Example: crash another node. +Either sends the given message, or call the given callback, after the +specified number of seconds. - snd $othernode, eval => "exit"; +This is simply a utility function that comes in handy at times - the +AnyEvent::MP author is not convinced of the wisdom of having it, though, +so it may go away in the future. =cut -rcv "", eval => sub { - my (undef, $string, @reply) = @_; - my @res = eval $string; - snd @reply, "$@", @res if @reply; -}; +sub after($@) { + my ($timeout, @action) = @_; -=item time => @reply + my $t; $t = AE::timer $timeout, 0, sub { + undef $t; + ref $action[0] + ? $action[0]() + : snd @action; + }; +} -Replies the the current node time to C<@reply>. +=back -Example: tell the current node to send the current time to C<$myport> in a -C message. +=head1 AnyEvent::MP vs. Distributed Erlang - snd $NODE, time => $myport, timereply => 1, 2; - # => snd $myport, timereply => 1, 2,