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Revision 1.1 by root, Thu Jul 30 08:38:50 2009 UTC vs.
Revision 1.17 by root, Mon Aug 3 08:35:40 2009 UTC

4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use AnyEvent::MP; 7 use AnyEvent::MP;
8 8
9 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
9=head1 DESCRIPTION 25=head1 DESCRIPTION
10 26
27This module (-family) implements a simple message passing framework.
28
29Despite its simplicity, you can securely message other processes running
30on the same or other hosts.
31
32At the moment, this module family is severly brokena nd underdocumented,
33so do not use. This was uploaded mainly to resreve the CPAN namespace -
34stay tuned!
35
36=head1 CONCEPTS
37
38=over 4
39
40=item port
41
42A port is something you can send messages to with the C<snd> function, and
43you can register C<rcv> handlers with. All C<rcv> handlers will receive
44messages they match, messages will not be queued.
45
46=item port id - C<noderef#portname>
47
48A port id is always the noderef, a hash-mark (C<#>) as separator, followed
49by a port name (a printable string of unspecified format).
50
51=item node
52
53A node is a single process containing at least one port - the node
54port. You can send messages to node ports to let them create new ports,
55among other things.
56
57Initially, nodes are either private (single-process only) or hidden
58(connected to a master node only). Only when they epxlicitly "become
59public" can you send them messages from unrelated other nodes.
60
61=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
62
63A noderef is a string that either uniquely identifies a given node (for
64private and hidden nodes), or contains a recipe on how to reach a given
65node (for public nodes).
66
67=back
68
69=head1 VARIABLES/FUNCTIONS
70
71=over 4
72
11=cut 73=cut
12 74
13package AnyEvent::MP; 75package AnyEvent::MP;
14 76
77use AnyEvent::MP::Base;
78
15use common::sense; 79use common::sense;
16 80
81use Carp ();
82
17use AE (); 83use AE ();
18 84
85use base "Exporter";
86
19our $VERSION = '0.0'; 87our $VERSION = '0.02';
88our @EXPORT = qw(
89 NODE $NODE $PORT snd rcv _any_
90 create_port create_port_on
91 create_miniport
92 become_slave become_public
93);
20 94
21sub nonce($) { 95=item NODE / $NODE
22 my $nonce;
23 96
24 if (open my $fh, "</dev/urandom") { 97The C<NODE ()> function and the C<$NODE> variable contain the noderef of
25 sysread $fh, $nonce, $_[0]; 98the local node. The value is initialised by a call to C<become_public> or
99C<become_slave>, after which all local port identifiers become invalid.
100
101=item snd $portid, type => @data
102
103=item snd $portid, @msg
104
105Send the given message to the given port ID, which can identify either
106a local or a remote port, and can be either a string or soemthignt hat
107stringifies a sa port ID (such as a port object :).
108
109While the message can be about anything, it is highly recommended to use a
110string as first element (a portid, or some word that indicates a request
111type etc.).
112
113The message data effectively becomes read-only after a call to this
114function: modifying any argument is not allowed and can cause many
115problems.
116
117The type of data you can transfer depends on the transport protocol: when
118JSON is used, then only strings, numbers and arrays and hashes consisting
119of those are allowed (no objects). When Storable is used, then anything
120that Storable can serialise and deserialise is allowed, and for the local
121node, anything can be passed.
122
123=item $local_port = create_port
124
125Create a new local port object. See the next section for allowed methods.
126
127=cut
128
129sub 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
151 for (@{ $self->{any} }) {
152 $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
153 && &{$_->[0]}
154 && undef $_;
155 }
156 };
157
158 $self
159}
160
161=item $portid = miniport { my @msg = @_; $finished }
162
163Creates a "mini port", that is, a very lightweight port without any
164pattern matching behind it, and returns its ID.
165
166The block will be called for every message received on the port. When the
167callback returns a true value its job is considered "done" and the port
168will be destroyed. Otherwise it will stay alive.
169
170The message will be passed as-is, no extra argument (i.e. no port id) will
171be passed to the callback.
172
173If 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
179=cut
180
181sub miniport(&) {
182 my $cb = shift;
183 my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
184
185 $AnyEvent::MP::Base::PORT{$id} = sub {
186 &$cb
187 and delete $AnyEvent::MP::Base::PORT{$id};
188 };
189
190 "$NODE#$id"
191}
192
193package AnyEvent::MP::Port;
194
195=back
196
197=head1 METHODS FOR PORT OBJECTS
198
199=over 4
200
201=item "$port"
202
203A port object stringifies to its port ID, so can be used directly for
204C<snd> operations.
205
206=cut
207
208use overload
209 '""' => sub { $_[0]{id} },
210 fallback => 1;
211
212=item $port->rcv (type => $callback->($port, @msg))
213
214=item $port->rcv ($smartmatch => $callback->($port, @msg))
215
216=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
217
218Register a callback on the given port.
219
220The callback has to return a true value when its work is done, after
221which is will be removed, or a false value in which case it will stay
222registered.
223
224If the match is an array reference, then it will be matched against the
225first elements of the message, otherwise only the first element is being
226matched.
227
228Any element in the match that is specified as C<_any_> (a function
229exported by this module) matches any single element of the message.
230
231While not required, it is highly recommended that the first matching
232element is a string identifying the message. The one-string-only match is
233also the most efficient match (by far).
234
235=cut
236
237sub rcv($@) {
238 my ($self, $match, $cb) = @_;
239
240 if (!ref $match) {
241 push @{ $self->{rc0}{$match} }, [$cb];
242 } elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
243 my ($type, @match) = @$match;
244 @match
245 ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
246 : push @{ $self->{rc0}{$match->[0]} }, [$cb];
26 } else { 247 } else {
27 # shit... 248 push @{ $self->{any} }, [$cb, $match];
28 our $nonce_init;
29 unless ($nonce_init++) {
30 srand time ^ $$ ^ unpack "%L*", qx"ps -edalf" . qx"ipconfig /all";
31 }
32
33 $nonce = join "", map +(chr rand 256), 1 .. $_[0]
34 } 249 }
35
36 $nonce
37} 250}
38 251
39our $DEFAULT_SECRET; 252=item $port->register ($name)
40 253
41sub default_secret { 254Registers the given port under the well known name C<$name>. If the name
42 unless (defined $DEFAULT_SECRET) { 255already exists it is replaced.
43 if (open my $fh, "<$ENV{HOME}/.aemp-secret") {
44 sysread $fh, $DEFAULT_SECRET, -s $fh;
45 } else {
46 $DEFAULT_SECRET = nonce 32;
47 }
48 }
49 256
50 $DEFAULT_SECRET 257A port can only be registered under one well known name.
258
259=cut
260
261sub register {
262 my ($self, $name) = @_;
263
264 $self->{wkname} = $name;
265 $AnyEvent::MP::Base::WKP{$name} = "$self";
51} 266}
267
268=item $port->destroy
269
270Explicitly destroy/remove/nuke/vaporise the port.
271
272Ports are normally kept alive by there mere existance alone, and need to
273be destroyed explicitly.
274
275=cut
276
277sub destroy {
278 my ($self) = @_;
279
280 delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
281
282 delete $AnyEvent::MP::Base::PORT{$_}
283 for @{ $self->{names} };
284}
285
286=back
287
288=head1 FUNCTIONS FOR NODES
289
290=over 4
291
292=item mon $noderef, $callback->($noderef, $status, $)
293
294Monitors the given noderef.
295
296=item become_public endpoint...
297
298Tells the node to become a public node, i.e. reachable from other nodes.
299
300If no arguments are given, or the first argument is C<undef>, then
301AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
302local nodename resolves to.
303
304Otherwise the first argument must be an array-reference with transport
305endpoints ("ip:port", "hostname:port") or port numbers (in which case the
306local nodename is used as hostname). The endpoints are all resolved and
307will become the node reference.
308
309=cut
310
311=back
312
313=head1 NODE MESSAGES
314
315Nodes understand the following messages sent to them. Many of them take
316arguments called C<@reply>, which will simply be used to compose a reply
317message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
318the remaining arguments are simply the message data.
319
320=over 4
321
322=cut
323
324=item wkp => $name, @reply
325
326Replies with the port ID of the specified well-known port, or C<undef>.
327
328=item devnull => ...
329
330Generic data sink/CPU heat conversion.
331
332=item relay => $port, @msg
333
334Simply forwards the message to the given port.
335
336=item eval => $string[ @reply]
337
338Evaluates the given string. If C<@reply> is given, then a message of the
339form C<@reply, $@, @evalres> is sent.
340
341Example: crash another node.
342
343 snd $othernode, eval => "exit";
344
345=item time => @reply
346
347Replies the the current node time to C<@reply>.
348
349Example: tell the current node to send the current time to C<$myport> in a
350C<timereply> message.
351
352 snd $NODE, time => $myport, timereply => 1, 2;
353 # => snd $myport, timereply => 1, 2, <time>
354
355=back
52 356
53=head1 SEE ALSO 357=head1 SEE ALSO
54 358
55L<AnyEvent>. 359L<AnyEvent>.
56 360

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