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
   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 $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 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:	1.17
Committed:	Mon Aug 3 08:35:40 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.16:	+1 -1 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	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	1.8	=item $local_port = create_port
124
125			Create a new local port object. See the next section for allowed methods.
126
127	root	1.3	=cut
128
129	root	1.8	sub create_port {
130	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
131	root	1.8
132			my $self = bless {
133			id => "$NODE#$id",
134			names => [$id],
135			}, "AnyEvent::MP::Port";
136
137			$AnyEvent::MP::Base::PORT{$id} = sub {
138			unshift @_, $self;
139
140			for (@{ $self->{rc0}{$_[1]} }) {
141			$_ && &{$_->[0]}
142			&& undef $_;
143			}
144
145			for (@{ $self->{rcv}{$_[1]} }) {
146			$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
147			&& &{$_->[0]}
148			&& undef $_;
149			}
150	root	1.2
151	root	1.8	for (@{ $self->{any} }) {
152			$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
153			&& &{$_->[0]}
154			&& undef $_;
155			}
156			};
157	root	1.2
158	root	1.8	$self
159	root	1.3	}
160
161	root	1.15	=item $portid = miniport { my @msg = @_; $finished }
162	root	1.10
163	root	1.15	Creates a "mini port", that is, a very lightweight port without any
164			pattern matching behind it, and returns its ID.
165
166			The block will be called for every message received on the port. When the
167			callback returns a true value its job is considered "done" and the port
168			will be destroyed. Otherwise it will stay alive.
169
170	root	1.17	The message will be passed as-is, no extra argument (i.e. no port id) will
171	root	1.15	be passed to the callback.
172
173			If you need the local port id in the callback, this works nicely:
174
175			my $port; $port = miniport {
176			snd $otherport, reply => $port;
177			};
178	root	1.10
179			=cut
180
181	root	1.15	sub miniport(&) {
182	root	1.10	my $cb = shift;
183	root	1.16	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
184	root	1.10
185			$AnyEvent::MP::Base::PORT{$id} = sub {
186			&$cb
187			and delete $AnyEvent::MP::Base::PORT{$id};
188			};
189
190			"$NODE#$id"
191			}
192
193	root	1.8	package AnyEvent::MP::Port;
194
195			=back
196
197			=head1 METHODS FOR PORT OBJECTS
198
199			=over 4
200
201			=item "$port"
202
203			A port object stringifies to its port ID, so can be used directly for
204			C<snd> operations.
205
206			=cut
207
208			use overload
209			'""' => sub { $_[0]{id} },
210			fallback => 1;
211
212			=item $port->rcv (type => $callback->($port, @msg))
213	root	1.3
214	root	1.8	=item $port->rcv ($smartmatch => $callback->($port, @msg))
215	root	1.3
216	root	1.8	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
217	root	1.3
218	root	1.8	Register a callback on the given port.
219	root	1.3
220			The callback has to return a true value when its work is done, after
221			which is will be removed, or a false value in which case it will stay
222			registered.
223
224			If the match is an array reference, then it will be matched against the
225			first elements of the message, otherwise only the first element is being
226			matched.
227
228			Any element in the match that is specified as C<_any_> (a function
229			exported by this module) matches any single element of the message.
230
231			While not required, it is highly recommended that the first matching
232			element is a string identifying the message. The one-string-only match is
233			also the most efficient match (by far).
234
235			=cut
236
237			sub rcv($@) {
238	root	1.8	my ($self, $match, $cb) = @_;
239	root	1.3
240			if (!ref $match) {
241	root	1.8	push @{ $self->{rc0}{$match} }, [$cb];
242	root	1.3	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
243			my ($type, @match) = @$match;
244			@match
245	root	1.8	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
246			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
247	root	1.3	} else {
248	root	1.8	push @{ $self->{any} }, [$cb, $match];
249	root	1.3	}
250	root	1.2	}
251
252	root	1.8	=item $port->register ($name)
253	root	1.2
254	root	1.8	Registers the given port under the well known name C<$name>. If the name
255			already exists it is replaced.
256	root	1.2
257	root	1.8	A port can only be registered under one well known name.
258	root	1.3
259	root	1.8	=cut
260	root	1.3
261	root	1.8	sub register {
262			my ($self, $name) = @_;
263	root	1.3
264	root	1.8	$self->{wkname} = $name;
265			$AnyEvent::MP::Base::WKP{$name} = "$self";
266	root	1.1	}
267
268	root	1.8	=item $port->destroy
269	root	1.2
270	root	1.8	Explicitly destroy/remove/nuke/vaporise the port.
271	root	1.2
272	root	1.8	Ports are normally kept alive by there mere existance alone, and need to
273			be destroyed explicitly.
274	root	1.2
275	root	1.8	=cut
276	root	1.1
277	root	1.8	sub destroy {
278			my ($self) = @_;
279	root	1.1
280	root	1.8	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
281	root	1.2
282	root	1.8	delete $AnyEvent::MP::Base::PORT{$_}
283			for @{ $self->{names} };
284	root	1.2	}
285
286	root	1.8	=back
287
288			=head1 FUNCTIONS FOR NODES
289
290			=over 4
291	root	1.2
292	root	1.8	=item mon $noderef, $callback->($noderef, $status, $)
293	root	1.2
294	root	1.8	Monitors the given noderef.
295	root	1.2
296	root	1.8	=item become_public endpoint...
297
298			Tells the node to become a public node, i.e. reachable from other nodes.
299
300			If no arguments are given, or the first argument is C<undef>, then
301			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
302			local nodename resolves to.
303
304			Otherwise the first argument must be an array-reference with transport
305			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
306			local nodename is used as hostname). The endpoints are all resolved and
307			will become the node reference.
308	root	1.2
309	root	1.8	=cut
310	root	1.1
311	root	1.4	=back
312
313			=head1 NODE MESSAGES
314
315	root	1.5	Nodes understand the following messages sent to them. Many of them take
316			arguments called C<@reply>, which will simply be used to compose a reply
317			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
318			the remaining arguments are simply the message data.
319	root	1.4
320			=over 4
321
322			=cut
323
324	root	1.8	=item wkp => $name, @reply
325	root	1.3
326	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
327	root	1.3
328	root	1.7	=item devnull => ...
329
330			Generic data sink/CPU heat conversion.
331
332	root	1.4	=item relay => $port, @msg
333
334			Simply forwards the message to the given port.
335
336			=item eval => $string[ @reply]
337
338			Evaluates the given string. If C<@reply> is given, then a message of the
339	root	1.5	form C<@reply, $@, @evalres> is sent.
340
341			Example: crash another node.
342
343			snd $othernode, eval => "exit";
344	root	1.4
345			=item time => @reply
346
347			Replies the the current node time to C<@reply>.
348
349	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
350			C<timereply> message.
351
352			snd $NODE, time => $myport, timereply => 1, 2;
353			# => snd $myport, timereply => 1, 2, <time>
354
355	root	1.2	=back
356
357	root	1.1	=head1 SEE ALSO
358
359			L<AnyEvent>.
360
361			=head1 AUTHOR
362
363			Marc Lehmann <schmorp@schmorp.de>
364			http://home.schmorp.de/
365
366			=cut
367
368			1
369