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 = 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 {
      $_[0] = "$NODE#$id";
      &$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:	1.12
Committed:	Sun Aug 2 18:11:48 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.11:	+1 -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	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			my $id = "$AnyEvent::MP::Base::UNIQ." . ++$AnyEvent::MP::Base::ID;
131
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	1.10	=item $portid = create_miniport { }
162
163			Creates a "mini port", that is, a port without much #TODO
164
165			=cut
166
167			sub create_miniport(&) {
168			my $cb = shift;
169			my $id = "$AnyEvent::MP::Base::UNIQ." . ++$AnyEvent::MP::Base::ID;
170
171			$AnyEvent::MP::Base::PORT{$id} = sub {
172	root	1.12	$_[0] = "$NODE#$id";
173	root	1.10	&$cb
174			and delete $AnyEvent::MP::Base::PORT{$id};
175			};
176
177			"$NODE#$id"
178			}
179
180	root	1.8	package AnyEvent::MP::Port;
181
182			=back
183
184			=head1 METHODS FOR PORT OBJECTS
185
186			=over 4
187
188			=item "$port"
189
190			A port object stringifies to its port ID, so can be used directly for
191			C<snd> operations.
192
193			=cut
194
195			use overload
196			'""' => sub { $_[0]{id} },
197			fallback => 1;
198
199			=item $port->rcv (type => $callback->($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	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
204	root	1.3
205	root	1.8	Register a callback on the given port.
206	root	1.3
207			The callback has to return a true value when its work is done, after
208			which is will be removed, or a false value in which case it will stay
209			registered.
210
211			If the match is an array reference, then it will be matched against the
212			first elements of the message, otherwise only the first element is being
213			matched.
214
215			Any element in the match that is specified as C<_any_> (a function
216			exported by this module) matches any single element of the message.
217
218			While not required, it is highly recommended that the first matching
219			element is a string identifying the message. The one-string-only match is
220			also the most efficient match (by far).
221
222			=cut
223
224			sub rcv($@) {
225	root	1.8	my ($self, $match, $cb) = @_;
226	root	1.3
227			if (!ref $match) {
228	root	1.8	push @{ $self->{rc0}{$match} }, [$cb];
229	root	1.3	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
230			my ($type, @match) = @$match;
231			@match
232	root	1.8	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
233			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
234	root	1.3	} else {
235	root	1.8	push @{ $self->{any} }, [$cb, $match];
236	root	1.3	}
237	root	1.2	}
238
239	root	1.8	=item $port->register ($name)
240	root	1.2
241	root	1.8	Registers the given port under the well known name C<$name>. If the name
242			already exists it is replaced.
243	root	1.2
244	root	1.8	A port can only be registered under one well known name.
245	root	1.3
246	root	1.8	=cut
247	root	1.3
248	root	1.8	sub register {
249			my ($self, $name) = @_;
250	root	1.3
251	root	1.8	$self->{wkname} = $name;
252			$AnyEvent::MP::Base::WKP{$name} = "$self";
253	root	1.1	}
254
255	root	1.8	=item $port->destroy
256	root	1.2
257	root	1.8	Explicitly destroy/remove/nuke/vaporise the port.
258	root	1.2
259	root	1.8	Ports are normally kept alive by there mere existance alone, and need to
260			be destroyed explicitly.
261	root	1.2
262	root	1.8	=cut
263	root	1.1
264	root	1.8	sub destroy {
265			my ($self) = @_;
266	root	1.1
267	root	1.8	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
268	root	1.2
269	root	1.8	delete $AnyEvent::MP::Base::PORT{$_}
270			for @{ $self->{names} };
271	root	1.2	}
272
273	root	1.8	=back
274
275			=head1 FUNCTIONS FOR NODES
276
277			=over 4
278	root	1.2
279	root	1.8	=item mon $noderef, $callback->($noderef, $status, $)
280	root	1.2
281	root	1.8	Monitors the given noderef.
282	root	1.2
283	root	1.8	=item become_public endpoint...
284
285			Tells the node to become a public node, i.e. reachable from other nodes.
286
287			If no arguments are given, or the first argument is C<undef>, then
288			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
289			local nodename resolves to.
290
291			Otherwise the first argument must be an array-reference with transport
292			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
293			local nodename is used as hostname). The endpoints are all resolved and
294			will become the node reference.
295	root	1.2
296	root	1.8	=cut
297	root	1.1
298	root	1.4	=back
299
300			=head1 NODE MESSAGES
301
302	root	1.5	Nodes understand the following messages sent to them. Many of them take
303			arguments called C<@reply>, which will simply be used to compose a reply
304			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
305			the remaining arguments are simply the message data.
306	root	1.4
307			=over 4
308
309			=cut
310
311	root	1.8	=item wkp => $name, @reply
312	root	1.3
313	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
314	root	1.3
315	root	1.7	=item devnull => ...
316
317			Generic data sink/CPU heat conversion.
318
319	root	1.4	=item relay => $port, @msg
320
321			Simply forwards the message to the given port.
322
323			=item eval => $string[ @reply]
324
325			Evaluates the given string. If C<@reply> is given, then a message of the
326	root	1.5	form C<@reply, $@, @evalres> is sent.
327
328			Example: crash another node.
329
330			snd $othernode, eval => "exit";
331	root	1.4
332			=item time => @reply
333
334			Replies the the current node time to C<@reply>.
335
336	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
337			C<timereply> message.
338
339			snd $NODE, time => $myport, timereply => 1, 2;
340			# => snd $myport, timereply => 1, 2, <time>
341
342	root	1.2	=back
343
344	root	1.1	=head1 SEE ALSO
345
346			L<AnyEvent>.
347
348			=head1 AUTHOR
349
350			Marc Lehmann <schmorp@schmorp.de>
351			http://home.schmorp.de/
352
353			=cut
354
355			1
356