AnyEvent-MP/MP.pm

=head1 NAME

AnyEvent::MP - multi-processing/message-passing framework

=head1 SYNOPSIS

   use AnyEvent::MP;

   NODE    # returns this node identifier
   $NODE   # contains this node identifier

   snd $port, type => data...;

   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.

At the moment, this module family is severly brokena nd underdocumented,
so do not use. This was uploaded mainly to resreve the CPAN namespace -
stay tuned!

=head1 CONCEPTS

=over 4

=item port

A port is something you can send messages to with the C<snd> function, and
you can register C<rcv> handlers with. All C<rcv> handlers will receive
messages they match, messages will not be queued.

=item port id - C<noderef#portname>

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 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<host:port,host:port...>, C<id@noderef>, C<id>

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).

=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 = '0.02';
our @EXPORT = qw(
   NODE $NODE $PORT snd rcv mon del _any_
   create_port create_port_on
   create_miniport
   become_slave become_public
);

=item NODE / $NODE

The C<NODE ()> function and the C<$NODE> variable contain the noderef of
the local node. The value is initialised by a call to C<become_public> or
C<become_slave>, after which all local port identifiers become invalid.

=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 $guard = mon $portid, $cb->()

Monitor the given port and call the given callback when the port is
destroyed or connection to it's node is lost.

#TODO

=cut

sub mon {
   my ($noderef, $port) = split /#/, shift, 2;

   my $node = AnyEvent::MP::Base::add_node $noderef;

   my $cb = shift;

   $node->monitor ($port, $cb);

   defined wantarray
      and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
}

=item $local_port = create_port

Create a new local port object. See the next section for allowed methods.

=cut

sub create_port {
   my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;

   my $self = bless {
      id    => "$NODE#$id",
      names => [$id],
   }, "AnyEvent::MP::Port";

   $AnyEvent::MP::Base::PORT{$id} = sub {
      unshift @_, $self;

      for (@{ $self->{rc0}{$_[1]} }) {
         $_ && &{$_->[0]}
            && undef $_;
      }

      for (@{ $self->{rcv}{$_[1]} }) {
         $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
            && &{$_->[0]}
            && undef $_;
      }

      for (@{ $self->{any} }) {
         $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
            && &{$_->[0]}
            && undef $_;
      }
   };

   $self
}

=item $portid = miniport { 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 miniport(&) {
   my $cb = shift;
   my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;

   $AnyEvent::MP::Base::PORT{$id} = sub {
      &$cb
         and del $id;
   };

   "$NODE#$id"
}

package AnyEvent::MP::Port;

=back

=head1 METHODS FOR PORT OBJECTS

=over 4

=item "$port"

A port object stringifies to its port ID, so can be used directly for
C<snd> operations.

=cut

use overload
   '""'     => sub { $_[0]{id} },
   fallback => 1;

sub TO_JSON { $_[0]{id} }

=item $port->rcv (type => $callback->($port, @msg))

=item $port->rcv ($smartmatch => $callback->($port, @msg))

=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))

Register a callback 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.

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($@) {
   my ($self, $match, $cb) = @_;

   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 $port->register ($name)

Registers the given port under the well known name C<$name>. If the name
already exists it is replaced.

A port can only be registered under one well known name.

=cut

sub register {
   my ($self, $name) = @_;

   $self->{wkname} = $name;
   $AnyEvent::MP::Base::WKP{$name} = "$self";
}

=item $port->destroy

Explicitly destroy/remove/nuke/vaporise the port.

Ports are normally kept alive by there mere existance alone, and need to
be destroyed explicitly.

=cut

sub destroy {
   my ($self) = @_;

   AnyEvent::MP::Base::del $self->{id};

   delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };

   delete $AnyEvent::MP::Base::PORT{$_}
      for @{ $self->{names} };
}

=back

=head1 FUNCTIONS FOR NODES

=over 4

=item mon $noderef, $callback->($noderef, $status, $)

Monitors the given noderef.

=item become_public endpoint...

Tells the node to become a public node, i.e. reachable from other nodes.

If no arguments are given, or the first argument is C<undef>, then
AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
local nodename resolves to.

Otherwise the first argument must be an array-reference with transport
endpoints ("ip:port", "hostname:port") or port numbers (in which case the
local nodename is used as hostname). The endpoints are all resolved and
will become the node reference.

=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.

=over 4

=cut

=item wkp => $name, @reply

Replies with the port ID of the specified well-known port, or C<undef>.

=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<timereply> message.

   snd $NODE, time => $myport, timereply => 1, 2;
   # => snd $myport, timereply => 1, 2, <time>

=back

=head1 SEE ALSO

L<AnyEvent>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.20
Committed:	Mon Aug 3 22:05:55 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.19:	+5 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MP - multi-processing/message-passing framework
4
5			=head1 SYNOPSIS
6
7			use AnyEvent::MP;
8
9	root	1.2	NODE # returns this node identifier
10			$NODE # contains this node identifier
11
12			snd $port, type => data...;
13
14			rcv $port, smartmatch => $cb->($port, @msg);
15
16			# examples:
17			rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
18			rcv $port1, pong => sub { warn "pong received\n" };
19			snd $port2, ping => $port1;
20
21			# more, smarter, matches (_any_ is exported by this module)
22			rcv $port, [child_died => $pid] => sub { ...
23			rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
24
25	root	1.1	=head1 DESCRIPTION
26
27	root	1.2	This module (-family) implements a simple message passing framework.
28
29			Despite its simplicity, you can securely message other processes running
30			on the same or other hosts.
31
32	root	1.6	At the moment, this module family is severly brokena nd underdocumented,
33			so do not use. This was uploaded mainly to resreve the CPAN namespace -
34			stay tuned!
35
36	root	1.2	=head1 CONCEPTS
37
38			=over 4
39
40			=item port
41
42			A port is something you can send messages to with the C<snd> function, and
43			you can register C<rcv> handlers with. All C<rcv> handlers will receive
44			messages they match, messages will not be queued.
45
46	root	1.3	=item port id - C<noderef#portname>
47	root	1.2
48	root	1.3	A port id is always the noderef, a hash-mark (C<#>) as separator, followed
49			by a port name (a printable string of unspecified format).
50	root	1.2
51			=item node
52
53			A node is a single process containing at least one port - the node
54			port. You can send messages to node ports to let them create new ports,
55			among other things.
56
57			Initially, nodes are either private (single-process only) or hidden
58	root	1.3	(connected to a master node only). Only when they epxlicitly "become
59			public" can you send them messages from unrelated other nodes.
60	root	1.2
61	root	1.5	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
62	root	1.2
63	root	1.3	A noderef is a string that either uniquely identifies a given node (for
64	root	1.2	private and hidden nodes), or contains a recipe on how to reach a given
65			node (for public nodes).
66
67			=back
68
69	root	1.3	=head1 VARIABLES/FUNCTIONS
70	root	1.2
71			=over 4
72
73	root	1.1	=cut
74
75			package AnyEvent::MP;
76
77	root	1.8	use AnyEvent::MP::Base;
78	root	1.2
79	root	1.1	use common::sense;
80
81	root	1.2	use Carp ();
82
83	root	1.1	use AE ();
84
85	root	1.2	use base "Exporter";
86
87	root	1.9	our $VERSION = '0.02';
88	root	1.8	our @EXPORT = qw(
89	root	1.18	NODE $NODE $PORT snd rcv mon del _any_
90	root	1.8	create_port create_port_on
91	root	1.11	create_miniport
92	root	1.8	become_slave become_public
93			);
94	root	1.2
95	root	1.3	=item NODE / $NODE
96
97			The C<NODE ()> function and the C<$NODE> variable contain the noderef of
98			the local node. The value is initialised by a call to C<become_public> or
99			C<become_slave>, after which all local port identifiers become invalid.
100
101			=item snd $portid, type => @data
102
103			=item snd $portid, @msg
104
105	root	1.8	Send the given message to the given port ID, which can identify either
106			a local or a remote port, and can be either a string or soemthignt hat
107			stringifies a sa port ID (such as a port object :).
108
109			While the message can be about anything, it is highly recommended to use a
110			string as first element (a portid, or some word that indicates a request
111			type etc.).
112	root	1.3
113			The message data effectively becomes read-only after a call to this
114			function: modifying any argument is not allowed and can cause many
115			problems.
116
117			The type of data you can transfer depends on the transport protocol: when
118			JSON is used, then only strings, numbers and arrays and hashes consisting
119			of those are allowed (no objects). When Storable is used, then anything
120			that Storable can serialise and deserialise is allowed, and for the local
121			node, anything can be passed.
122
123	root	1.20	=item $guard = mon $portid, $cb->()
124	root	1.18
125	root	1.20	Monitor the given port and call the given callback when the port is
126			destroyed or connection to it's node is lost.
127
128			#TODO
129	root	1.18
130			=cut
131
132			sub mon {
133			my ($noderef, $port) = split /#/, shift, 2;
134
135			my $node = AnyEvent::MP::Base::add_node $noderef;
136
137			my $cb = shift;
138
139			$node->monitor ($port, $cb);
140
141			defined wantarray
142			and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
143			}
144
145	root	1.8	=item $local_port = create_port
146
147			Create a new local port object. See the next section for allowed methods.
148
149	root	1.3	=cut
150
151	root	1.8	sub create_port {
152	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
153	root	1.8
154			my $self = bless {
155			id => "$NODE#$id",
156			names => [$id],
157			}, "AnyEvent::MP::Port";
158
159			$AnyEvent::MP::Base::PORT{$id} = sub {
160			unshift @_, $self;
161
162			for (@{ $self->{rc0}{$_[1]} }) {
163			$_ && &{$_->[0]}
164			&& undef $_;
165			}
166
167			for (@{ $self->{rcv}{$_[1]} }) {
168			$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
169			&& &{$_->[0]}
170			&& undef $_;
171			}
172	root	1.2
173	root	1.8	for (@{ $self->{any} }) {
174			$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
175			&& &{$_->[0]}
176			&& undef $_;
177			}
178			};
179	root	1.2
180	root	1.8	$self
181	root	1.3	}
182
183	root	1.15	=item $portid = miniport { my @msg = @_; $finished }
184	root	1.10
185	root	1.15	Creates a "mini port", that is, a very lightweight port without any
186			pattern matching behind it, and returns its ID.
187
188			The block will be called for every message received on the port. When the
189			callback returns a true value its job is considered "done" and the port
190			will be destroyed. Otherwise it will stay alive.
191
192	root	1.17	The message will be passed as-is, no extra argument (i.e. no port id) will
193	root	1.15	be passed to the callback.
194
195			If you need the local port id in the callback, this works nicely:
196
197			my $port; $port = miniport {
198			snd $otherport, reply => $port;
199			};
200	root	1.10
201			=cut
202
203	root	1.15	sub miniport(&) {
204	root	1.10	my $cb = shift;
205	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
206	root	1.10
207			$AnyEvent::MP::Base::PORT{$id} = sub {
208			&$cb
209	root	1.19	and del $id;
210	root	1.10	};
211
212			"$NODE#$id"
213			}
214
215	root	1.8	package AnyEvent::MP::Port;
216
217			=back
218
219			=head1 METHODS FOR PORT OBJECTS
220
221			=over 4
222
223			=item "$port"
224
225			A port object stringifies to its port ID, so can be used directly for
226			C<snd> operations.
227
228			=cut
229
230			use overload
231			'""' => sub { $_[0]{id} },
232			fallback => 1;
233
234	root	1.18	sub TO_JSON { $_[0]{id} }
235
236	root	1.8	=item $port->rcv (type => $callback->($port, @msg))
237	root	1.3
238	root	1.8	=item $port->rcv ($smartmatch => $callback->($port, @msg))
239	root	1.3
240	root	1.8	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
241	root	1.3
242	root	1.8	Register a callback on the given port.
243	root	1.3
244			The callback has to return a true value when its work is done, after
245			which is will be removed, or a false value in which case it will stay
246			registered.
247
248			If the match is an array reference, then it will be matched against the
249			first elements of the message, otherwise only the first element is being
250			matched.
251
252			Any element in the match that is specified as C<_any_> (a function
253			exported by this module) matches any single element of the message.
254
255			While not required, it is highly recommended that the first matching
256			element is a string identifying the message. The one-string-only match is
257			also the most efficient match (by far).
258
259			=cut
260
261			sub rcv($@) {
262	root	1.8	my ($self, $match, $cb) = @_;
263	root	1.3
264			if (!ref $match) {
265	root	1.8	push @{ $self->{rc0}{$match} }, [$cb];
266	root	1.3	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
267			my ($type, @match) = @$match;
268			@match
269	root	1.8	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
270			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
271	root	1.3	} else {
272	root	1.8	push @{ $self->{any} }, [$cb, $match];
273	root	1.3	}
274	root	1.2	}
275
276	root	1.8	=item $port->register ($name)
277	root	1.2
278	root	1.8	Registers the given port under the well known name C<$name>. If the name
279			already exists it is replaced.
280	root	1.2
281	root	1.8	A port can only be registered under one well known name.
282	root	1.3
283	root	1.8	=cut
284	root	1.3
285	root	1.8	sub register {
286			my ($self, $name) = @_;
287	root	1.3
288	root	1.8	$self->{wkname} = $name;
289			$AnyEvent::MP::Base::WKP{$name} = "$self";
290	root	1.1	}
291
292	root	1.8	=item $port->destroy
293	root	1.2
294	root	1.8	Explicitly destroy/remove/nuke/vaporise the port.
295	root	1.2
296	root	1.8	Ports are normally kept alive by there mere existance alone, and need to
297			be destroyed explicitly.
298	root	1.2
299	root	1.8	=cut
300	root	1.1
301	root	1.8	sub destroy {
302			my ($self) = @_;
303	root	1.1
304	root	1.18	AnyEvent::MP::Base::del $self->{id};
305
306	root	1.8	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
307	root	1.2
308	root	1.8	delete $AnyEvent::MP::Base::PORT{$_}
309			for @{ $self->{names} };
310	root	1.2	}
311
312	root	1.8	=back
313
314			=head1 FUNCTIONS FOR NODES
315
316			=over 4
317	root	1.2
318	root	1.8	=item mon $noderef, $callback->($noderef, $status, $)
319	root	1.2
320	root	1.8	Monitors the given noderef.
321	root	1.2
322	root	1.8	=item become_public endpoint...
323
324			Tells the node to become a public node, i.e. reachable from other nodes.
325
326			If no arguments are given, or the first argument is C<undef>, then
327			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
328			local nodename resolves to.
329
330			Otherwise the first argument must be an array-reference with transport
331			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
332			local nodename is used as hostname). The endpoints are all resolved and
333			will become the node reference.
334	root	1.2
335	root	1.8	=cut
336	root	1.1
337	root	1.4	=back
338
339			=head1 NODE MESSAGES
340
341	root	1.5	Nodes understand the following messages sent to them. Many of them take
342			arguments called C<@reply>, which will simply be used to compose a reply
343			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
344			the remaining arguments are simply the message data.
345	root	1.4
346			=over 4
347
348			=cut
349
350	root	1.8	=item wkp => $name, @reply
351	root	1.3
352	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
353	root	1.3
354	root	1.7	=item devnull => ...
355
356			Generic data sink/CPU heat conversion.
357
358	root	1.4	=item relay => $port, @msg
359
360			Simply forwards the message to the given port.
361
362			=item eval => $string[ @reply]
363
364			Evaluates the given string. If C<@reply> is given, then a message of the
365	root	1.5	form C<@reply, $@, @evalres> is sent.
366
367			Example: crash another node.
368
369			snd $othernode, eval => "exit";
370	root	1.4
371			=item time => @reply
372
373			Replies the the current node time to C<@reply>.
374
375	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
376			C<timereply> message.
377
378			snd $NODE, time => $myport, timereply => 1, 2;
379			# => snd $myport, timereply => 1, 2, <time>
380
381	root	1.2	=back
382
383	root	1.1	=head1 SEE ALSO
384
385			L<AnyEvent>.
386
387			=head1 AUTHOR
388
389			Marc Lehmann <schmorp@schmorp.de>
390			http://home.schmorp.de/
391
392			=cut
393
394			1
395