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 mon $portid, sub { }

#TODO monitor the given port

=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:	1.19
Committed:	Mon Aug 3 21:37:19 2009 UTC (14 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.18:	+1 -1 lines
Log Message:	first round of monitoring
#	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	1.18	=item mon $portid, sub { }
124
125			#TODO monitor the given port
126
127			=cut
128
129			sub mon {
130			my ($noderef, $port) = split /#/, shift, 2;
131
132			my $node = AnyEvent::MP::Base::add_node $noderef;
133
134			my $cb = shift;
135
136			$node->monitor ($port, $cb);
137
138			defined wantarray
139			and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
140			}
141
142	root	1.8	=item $local_port = create_port
143
144			Create a new local port object. See the next section for allowed methods.
145
146	root	1.3	=cut
147
148	root	1.8	sub create_port {
149	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
150	root	1.8
151			my $self = bless {
152			id => "$NODE#$id",
153			names => [$id],
154			}, "AnyEvent::MP::Port";
155
156			$AnyEvent::MP::Base::PORT{$id} = sub {
157			unshift @_, $self;
158
159			for (@{ $self->{rc0}{$_[1]} }) {
160			$_ && &{$_->[0]}
161			&& undef $_;
162			}
163
164			for (@{ $self->{rcv}{$_[1]} }) {
165			$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
166			&& &{$_->[0]}
167			&& undef $_;
168			}
169	root	1.2
170	root	1.8	for (@{ $self->{any} }) {
171			$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
172			&& &{$_->[0]}
173			&& undef $_;
174			}
175			};
176	root	1.2
177	root	1.8	$self
178	root	1.3	}
179
180	root	1.15	=item $portid = miniport { my @msg = @_; $finished }
181	root	1.10
182	root	1.15	Creates a "mini port", that is, a very lightweight port without any
183			pattern matching behind it, and returns its ID.
184
185			The block will be called for every message received on the port. When the
186			callback returns a true value its job is considered "done" and the port
187			will be destroyed. Otherwise it will stay alive.
188
189	root	1.17	The message will be passed as-is, no extra argument (i.e. no port id) will
190	root	1.15	be passed to the callback.
191
192			If you need the local port id in the callback, this works nicely:
193
194			my $port; $port = miniport {
195			snd $otherport, reply => $port;
196			};
197	root	1.10
198			=cut
199
200	root	1.15	sub miniport(&) {
201	root	1.10	my $cb = shift;
202	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
203	root	1.10
204			$AnyEvent::MP::Base::PORT{$id} = sub {
205			&$cb
206	root	1.19	and del $id;
207	root	1.10	};
208
209			"$NODE#$id"
210			}
211
212	root	1.8	package AnyEvent::MP::Port;
213
214			=back
215
216			=head1 METHODS FOR PORT OBJECTS
217
218			=over 4
219
220			=item "$port"
221
222			A port object stringifies to its port ID, so can be used directly for
223			C<snd> operations.
224
225			=cut
226
227			use overload
228			'""' => sub { $_[0]{id} },
229			fallback => 1;
230
231	root	1.18	sub TO_JSON { $_[0]{id} }
232
233	root	1.8	=item $port->rcv (type => $callback->($port, @msg))
234	root	1.3
235	root	1.8	=item $port->rcv ($smartmatch => $callback->($port, @msg))
236	root	1.3
237	root	1.8	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
238	root	1.3
239	root	1.8	Register a callback on the given port.
240	root	1.3
241			The callback has to return a true value when its work is done, after
242			which is will be removed, or a false value in which case it will stay
243			registered.
244
245			If the match is an array reference, then it will be matched against the
246			first elements of the message, otherwise only the first element is being
247			matched.
248
249			Any element in the match that is specified as C<_any_> (a function
250			exported by this module) matches any single element of the message.
251
252			While not required, it is highly recommended that the first matching
253			element is a string identifying the message. The one-string-only match is
254			also the most efficient match (by far).
255
256			=cut
257
258			sub rcv($@) {
259	root	1.8	my ($self, $match, $cb) = @_;
260	root	1.3
261			if (!ref $match) {
262	root	1.8	push @{ $self->{rc0}{$match} }, [$cb];
263	root	1.3	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
264			my ($type, @match) = @$match;
265			@match
266	root	1.8	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
267			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
268	root	1.3	} else {
269	root	1.8	push @{ $self->{any} }, [$cb, $match];
270	root	1.3	}
271	root	1.2	}
272
273	root	1.8	=item $port->register ($name)
274	root	1.2
275	root	1.8	Registers the given port under the well known name C<$name>. If the name
276			already exists it is replaced.
277	root	1.2
278	root	1.8	A port can only be registered under one well known name.
279	root	1.3
280	root	1.8	=cut
281	root	1.3
282	root	1.8	sub register {
283			my ($self, $name) = @_;
284	root	1.3
285	root	1.8	$self->{wkname} = $name;
286			$AnyEvent::MP::Base::WKP{$name} = "$self";
287	root	1.1	}
288
289	root	1.8	=item $port->destroy
290	root	1.2
291	root	1.8	Explicitly destroy/remove/nuke/vaporise the port.
292	root	1.2
293	root	1.8	Ports are normally kept alive by there mere existance alone, and need to
294			be destroyed explicitly.
295	root	1.2
296	root	1.8	=cut
297	root	1.1
298	root	1.8	sub destroy {
299			my ($self) = @_;
300	root	1.1
301	root	1.18	AnyEvent::MP::Base::del $self->{id};
302
303	root	1.8	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
304	root	1.2
305	root	1.8	delete $AnyEvent::MP::Base::PORT{$_}
306			for @{ $self->{names} };
307	root	1.2	}
308
309	root	1.8	=back
310
311			=head1 FUNCTIONS FOR NODES
312
313			=over 4
314	root	1.2
315	root	1.8	=item mon $noderef, $callback->($noderef, $status, $)
316	root	1.2
317	root	1.8	Monitors the given noderef.
318	root	1.2
319	root	1.8	=item become_public endpoint...
320
321			Tells the node to become a public node, i.e. reachable from other nodes.
322
323			If no arguments are given, or the first argument is C<undef>, then
324			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
325			local nodename resolves to.
326
327			Otherwise the first argument must be an array-reference with transport
328			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
329			local nodename is used as hostname). The endpoints are all resolved and
330			will become the node reference.
331	root	1.2
332	root	1.8	=cut
333	root	1.1
334	root	1.4	=back
335
336			=head1 NODE MESSAGES
337
338	root	1.5	Nodes understand the following messages sent to them. Many of them take
339			arguments called C<@reply>, which will simply be used to compose a reply
340			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
341			the remaining arguments are simply the message data.
342	root	1.4
343			=over 4
344
345			=cut
346
347	root	1.8	=item wkp => $name, @reply
348	root	1.3
349	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
350	root	1.3
351	root	1.7	=item devnull => ...
352
353			Generic data sink/CPU heat conversion.
354
355	root	1.4	=item relay => $port, @msg
356
357			Simply forwards the message to the given port.
358
359			=item eval => $string[ @reply]
360
361			Evaluates the given string. If C<@reply> is given, then a message of the
362	root	1.5	form C<@reply, $@, @evalres> is sent.
363
364			Example: crash another node.
365
366			snd $othernode, eval => "exit";
367	root	1.4
368			=item time => @reply
369
370			Replies the the current node time to C<@reply>.
371
372	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
373			C<timereply> message.
374
375			snd $NODE, time => $myport, timereply => 1, 2;
376			# => snd $myport, timereply => 1, 2, <time>
377
378	root	1.2	=back
379
380	root	1.1	=head1 SEE ALSO
381
382			L<AnyEvent>.
383
384			=head1 AUTHOR
385
386			Marc Lehmann <schmorp@schmorp.de>
387			http://home.schmorp.de/
388
389			=cut
390
391			1
392