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 _any_
   create_port create_port_on
   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 $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 = create_miniport { }

Creates a "mini port", that is, a port without much #TODO

=cut

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

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

=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) = @_;

   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:	1.10
Committed:	Sun Aug 2 18:05:43 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.9:	+18 -0 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			NODE $NODE $PORT snd rcv _any_
90			create_port create_port_on
91			become_slave become_public
92			);
93	root	1.2
94	root	1.3	=item NODE / $NODE
95
96			The C<NODE ()> function and the C<$NODE> variable contain the noderef of
97			the local node. The value is initialised by a call to C<become_public> or
98			C<become_slave>, after which all local port identifiers become invalid.
99
100			=item snd $portid, type => @data
101
102			=item snd $portid, @msg
103
104	root	1.8	Send the given message to the given port ID, which can identify either
105			a local or a remote port, and can be either a string or soemthignt hat
106			stringifies a sa port ID (such as a port object :).
107
108			While the message can be about anything, it is highly recommended to use a
109			string as first element (a portid, or some word that indicates a request
110			type etc.).
111	root	1.3
112			The message data effectively becomes read-only after a call to this
113			function: modifying any argument is not allowed and can cause many
114			problems.
115
116			The type of data you can transfer depends on the transport protocol: when
117			JSON is used, then only strings, numbers and arrays and hashes consisting
118			of those are allowed (no objects). When Storable is used, then anything
119			that Storable can serialise and deserialise is allowed, and for the local
120			node, anything can be passed.
121
122	root	1.8	=item $local_port = create_port
123
124			Create a new local port object. See the next section for allowed methods.
125
126	root	1.3	=cut
127
128	root	1.8	sub create_port {
129			my $id = "$AnyEvent::MP::Base::UNIQ." . ++$AnyEvent::MP::Base::ID;
130
131			my $self = bless {
132			id => "$NODE#$id",
133			names => [$id],
134			}, "AnyEvent::MP::Port";
135
136			$AnyEvent::MP::Base::PORT{$id} = sub {
137			unshift @_, $self;
138
139			for (@{ $self->{rc0}{$_[1]} }) {
140			$_ && &{$_->[0]}
141			&& undef $_;
142			}
143
144			for (@{ $self->{rcv}{$_[1]} }) {
145			$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
146			&& &{$_->[0]}
147			&& undef $_;
148			}
149	root	1.2
150	root	1.8	for (@{ $self->{any} }) {
151			$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
152			&& &{$_->[0]}
153			&& undef $_;
154			}
155			};
156	root	1.2
157	root	1.8	$self
158	root	1.3	}
159
160	root	1.10	=item $portid = create_miniport { }
161
162			Creates a "mini port", that is, a port without much #TODO
163
164			=cut
165
166			sub create_miniport(&) {
167			my $cb = shift;
168			my $id = "$AnyEvent::MP::Base::UNIQ." . ++$AnyEvent::MP::Base::ID;
169
170			$AnyEvent::MP::Base::PORT{$id} = sub {
171			&$cb
172			and delete $AnyEvent::MP::Base::PORT{$id};
173			};
174
175			"$NODE#$id"
176			}
177
178	root	1.8	package AnyEvent::MP::Port;
179
180			=back
181
182			=head1 METHODS FOR PORT OBJECTS
183
184			=over 4
185
186			=item "$port"
187
188			A port object stringifies to its port ID, so can be used directly for
189			C<snd> operations.
190
191			=cut
192
193			use overload
194			'""' => sub { $_[0]{id} },
195			fallback => 1;
196
197			=item $port->rcv (type => $callback->($port, @msg))
198	root	1.3
199	root	1.8	=item $port->rcv ($smartmatch => $callback->($port, @msg))
200	root	1.3
201	root	1.8	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
202	root	1.3
203	root	1.8	Register a callback on the given port.
204	root	1.3
205			The callback has to return a true value when its work is done, after
206			which is will be removed, or a false value in which case it will stay
207			registered.
208
209			If the match is an array reference, then it will be matched against the
210			first elements of the message, otherwise only the first element is being
211			matched.
212
213			Any element in the match that is specified as C<_any_> (a function
214			exported by this module) matches any single element of the message.
215
216			While not required, it is highly recommended that the first matching
217			element is a string identifying the message. The one-string-only match is
218			also the most efficient match (by far).
219
220			=cut
221
222			sub rcv($@) {
223	root	1.8	my ($self, $match, $cb) = @_;
224	root	1.3
225			if (!ref $match) {
226	root	1.8	push @{ $self->{rc0}{$match} }, [$cb];
227	root	1.3	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
228			my ($type, @match) = @$match;
229			@match
230	root	1.8	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
231			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
232	root	1.3	} else {
233	root	1.8	push @{ $self->{any} }, [$cb, $match];
234	root	1.3	}
235	root	1.2	}
236
237	root	1.8	=item $port->register ($name)
238	root	1.2
239	root	1.8	Registers the given port under the well known name C<$name>. If the name
240			already exists it is replaced.
241	root	1.2
242	root	1.8	A port can only be registered under one well known name.
243	root	1.3
244	root	1.8	=cut
245	root	1.3
246	root	1.8	sub register {
247			my ($self, $name) = @_;
248	root	1.3
249	root	1.8	$self->{wkname} = $name;
250			$AnyEvent::MP::Base::WKP{$name} = "$self";
251	root	1.1	}
252
253	root	1.8	=item $port->destroy
254	root	1.2
255	root	1.8	Explicitly destroy/remove/nuke/vaporise the port.
256	root	1.2
257	root	1.8	Ports are normally kept alive by there mere existance alone, and need to
258			be destroyed explicitly.
259	root	1.2
260	root	1.8	=cut
261	root	1.1
262	root	1.8	sub destroy {
263			my ($self) = @_;
264	root	1.1
265	root	1.8	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
266	root	1.2
267	root	1.8	delete $AnyEvent::MP::Base::PORT{$_}
268			for @{ $self->{names} };
269	root	1.2	}
270
271	root	1.8	=back
272
273			=head1 FUNCTIONS FOR NODES
274
275			=over 4
276	root	1.2
277	root	1.8	=item mon $noderef, $callback->($noderef, $status, $)
278	root	1.2
279	root	1.8	Monitors the given noderef.
280	root	1.2
281	root	1.8	=item become_public endpoint...
282
283			Tells the node to become a public node, i.e. reachable from other nodes.
284
285			If no arguments are given, or the first argument is C<undef>, then
286			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
287			local nodename resolves to.
288
289			Otherwise the first argument must be an array-reference with transport
290			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
291			local nodename is used as hostname). The endpoints are all resolved and
292			will become the node reference.
293	root	1.2
294	root	1.8	=cut
295	root	1.1
296	root	1.4	=back
297
298			=head1 NODE MESSAGES
299
300	root	1.5	Nodes understand the following messages sent to them. Many of them take
301			arguments called C<@reply>, which will simply be used to compose a reply
302			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
303			the remaining arguments are simply the message data.
304	root	1.4
305			=over 4
306
307			=cut
308
309	root	1.8	=item wkp => $name, @reply
310	root	1.3
311	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
312	root	1.3
313	root	1.7	=item devnull => ...
314
315			Generic data sink/CPU heat conversion.
316
317	root	1.4	=item relay => $port, @msg
318
319			Simply forwards the message to the given port.
320
321			=item eval => $string[ @reply]
322
323			Evaluates the given string. If C<@reply> is given, then a message of the
324	root	1.5	form C<@reply, $@, @evalres> is sent.
325
326			Example: crash another node.
327
328			snd $othernode, eval => "exit";
329	root	1.4
330			=item time => @reply
331
332			Replies the the current node time to C<@reply>.
333
334	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
335			C<timereply> message.
336
337			snd $NODE, time => $myport, timereply => 1, 2;
338			# => snd $myport, timereply => 1, 2, <time>
339
340	root	1.2	=back
341
342	root	1.1	=head1 SEE ALSO
343
344			L<AnyEvent>.
345
346			=head1 AUTHOR
347
348			Marc Lehmann <schmorp@schmorp.de>
349			http://home.schmorp.de/
350
351			=cut
352
353			1
354