[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs.
Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC

…		…
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node; # -OR-
		17	initialise_node "localhost:4040"; # -OR-
		18	initialise_node "slave/", "localhost:4040"
14		19
15	# ports are message endpoints	20	# ports are message endpoints
16		21
17	# sending messages	22	# sending messages
18	snd $port, type => data...;	23	snd $port, type => data...;
19	snd $port, @msg;	24	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	25	snd @msg_with_first_element_being_a_port;
21		26
22	# miniports	27	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	28	my $simple_port = port { my @msg = @_; 0 };
24		29
25	# full ports	30	# creating/using ports, tagged message matching
26	my $port = port;	31	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	32	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	33	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		34
31	# remote ports	35	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	36	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		37
38	# monitoring	38	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	39	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	40	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	41	mon $port, $otherport, @msg # send message on death
42		42
		43	=head1 CURRENT STATUS
		44
		45	AnyEvent::MP - stable API, should work
		46	AnyEvent::MP::Intro - outdated
		47	AnyEvent::MP::Kernel - WIP
		48	AnyEvent::MP::Transport - mostly stable
		49
		50	stay tuned.
		51
43	=head1 DESCRIPTION	52	=head1 DESCRIPTION
44		53
45	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
46		55
47	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
…		…
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	60	manual page.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is severly broken and underdocumented,
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -	63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.	64	stay tuned!
56		65
57	=head1 CONCEPTS	66	=head1 CONCEPTS
58		67
59	=over 4	68	=over 4
60		69
61	=item port	70	=item port
62		71
63	A port is something you can send messages to (with the C<snd> function).	72	A port is something you can send messages to (with the C<snd> function).
64		73
65	Some ports allow you to register C<rcv> handlers that can match specific	74	Ports allow you to register C<rcv> handlers that can match all or just
66	messages. All C<rcv> handlers will receive messages they match, messages	75	some messages. Messages will not be queued.
67	will not be queued.
68		76
69	=item port id - C<noderef#portname>	77	=item port id - C<noderef#portname>
70		78
71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	79	A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
72	separator, and a port name (a printable string of unspecified format). An	80	separator, and a port name (a printable string of unspecified format). An
73	exception is the the node port, whose ID is identical to its node	81	exception is the the node port, whose ID is identical to its node
74	reference.	82	reference.
75		83
76	=item node	84	=item node
77		85
78	A node is a single process containing at least one port - the node	86	A node is a single process containing at least one port - the node port,
79	port. You can send messages to node ports to find existing ports or to	87	which provides nodes to manage each other remotely, and to create new
80	create new ports, among other things.	88	ports.
81		89
82	Nodes are either private (single-process only), slaves (connected to a	90	Nodes are either private (single-process only), slaves (can only talk to
83	master node only) or public nodes (connectable from unrelated nodes).	91	public nodes, but do not need an open port) or public nodes (connectable
		92	from any other node).
84		93
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
86		95
87	A node reference is a string that either simply identifies the node (for	96	A node reference is a string that either simply identifies the node (for
88	private and slave nodes), or contains a recipe on how to reach a given	97	private and slave nodes), or contains a recipe on how to reach a given
…		…
105		114
106	=cut	115	=cut
107		116
108	package AnyEvent::MP;	117	package AnyEvent::MP;
109		118
110	use AnyEvent::MP::Base;	119	use AnyEvent::MP::Kernel;
111		120
112	use common::sense;	121	use common::sense;
113		122
114	use Carp ();	123	use Carp ();
115		124
116	use AE ();	125	use AE ();
117		126
118	use base "Exporter";	127	use base "Exporter";
119		128
120	our $VERSION = '0.1';	129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		130
121	our @EXPORT = qw(	131	our @EXPORT = qw(
122	NODE $NODE *SELF node_of _any_	132	NODE $NODE *SELF node_of after
123	resolve_node initialise_node	133	resolve_node initialise_node
124	snd rcv mon kil reg psub spawn	134	snd rcv mon mon_guard kil reg psub spawn
125	port	135	port
126	);	136	);
127		137
128	our $SELF;	138	our $SELF;
129		139
…		…
133	kil $SELF, die => $msg;	143	kil $SELF, die => $msg;
134	}	144	}
135		145
136	=item $thisnode = NODE / $NODE	146	=item $thisnode = NODE / $NODE
137		147
138	The C<NODE> function returns, and the C<$NODE> variable contains	148	The C<NODE> function returns, and the C<$NODE> variable contains the
139	the noderef of the local node. The value is initialised by a call	149	noderef of the local node. The value is initialised by a call to
140	to C<become_public> or C<become_slave>, after which all local port	150	C<initialise_node>.
141	identifiers become invalid.
142		151
143	=item $noderef = node_of $port	152	=item $noderef = node_of $port
144		153
145	Extracts and returns the noderef from a portid or a noderef.	154	Extracts and returns the noderef from a port ID or a noderef.
146		155
147	=item initialise_node $noderef, $seednode, $seednode...	156	=item initialise_node $noderef, $seednode, $seednode...
148		157
149	=item initialise_node "slave/", $master, $master...	158	=item initialise_node "slave/", $master, $master...
150		159
…		…
153	it should know the noderefs of some other nodes in the network.	162	it should know the noderefs of some other nodes in the network.
154		163
155	This function initialises a node - it must be called exactly once (or	164	This function initialises a node - it must be called exactly once (or
156	never) before calling other AnyEvent::MP functions.	165	never) before calling other AnyEvent::MP functions.
157		166
158	All arguments are noderefs, which can be either resolved or unresolved.	167	All arguments (optionally except for the first) are noderefs, which can be
		168	either resolved or unresolved.
		169
		170	The first argument will be looked up in the configuration database first
		171	(if it is C<undef> then the current nodename will be used instead) to find
		172	the relevant configuration profile (see L<aemp>). If none is found then
		173	the default configuration is used. The configuration supplies additional
		174	seed/master nodes and can override the actual noderef.
159		175
160	There are two types of networked nodes, public nodes and slave nodes:	176	There are two types of networked nodes, public nodes and slave nodes:
161		177
162	=over 4	178	=over 4
163		179
164	=item public nodes	180	=item public nodes
165		181
166	For public nodes, C<$noderef> must either be a (possibly unresolved)	182	For public nodes, C<$noderef> (supplied either directly to
167	noderef, in which case it will be resolved, or C<undef> (or missing), in	183	C<initialise_node> or indirectly via a profile or the nodename) must be a
168	which case the noderef will be guessed.	184	noderef (possibly unresolved, in which case it will be resolved).
169		185
170	Afterwards, the node will bind itself on all endpoints and try to connect	186	After resolving, the node will bind itself on all endpoints.
171	to all additional C<$seednodes> that are specified. Seednodes are optional
172	and can be used to quickly bootstrap the node into an existing network.
173		187
174	=item slave nodes	188	=item slave nodes
175		189
176	When the C<$noderef> is the special string C<slave/>, then the node will	190	When the C<$noderef> (either as given or overriden by the config file)
		191	is the special string C<slave/>, then the node will become a slave
177	become a slave node. Slave nodes cannot be contacted from outside and will	192	node. Slave nodes cannot be contacted from outside, and cannot talk to
178	route most of their traffic to the master node that they attach to.	193	each other (at least in this version of AnyEvent::MP).
179		194
180	At least one additional noderef is required: The node will try to connect	195	Slave nodes work by creating connections to all public nodes, using the
181	to all of them and will become a slave attached to the first node it can	196	L<AnyEvent::MP::Global> service.
182	successfully connect to.
183		197
184	=back	198	=back
185		199
186	This function will block until all nodes have been resolved and, for slave	200	After initialising itself, the node will connect to all additional
187	nodes, until it has successfully established a connection to a master	201	C<$seednodes> that are specified diretcly or via a profile. Seednodes are
188	server.	202	optional and can be used to quickly bootstrap the node into an existing
		203	network.
189		204
		205	All the seednodes will also be specially marked to automatically retry
		206	connecting to them indefinitely, so make sure that seednodes are really
		207	reliable and up (this might also change in the future).
		208
190	Example: become a public node listening on the default node.	209	Example: become a public node listening on the guessed noderef, or the one
		210	specified via C<aemp> for the current node. This should be the most common
		211	form of invocation for "daemon"-type nodes.
191		212
192	initialise_node;	213	initialise_node;
		214
		215	Example: become a slave node to any of the the seednodes specified via
		216	C<aemp>. This form is often used for commandline clients.
		217
		218	initialise_node "slave/";
193		219
194	Example: become a public node, and try to contact some well-known master	220	Example: become a public node, and try to contact some well-known master
195	servers to become part of the network.	221	servers to become part of the network.
196		222
197	initialise_node undef, "master1", "master2";	223	initialise_node undef, "master1", "master2";
…		…
200		226
201	initialise_node 4041;	227	initialise_node 4041;
202		228
203	Example: become a public node, only visible on localhost port 4044.	229	Example: become a public node, only visible on localhost port 4044.
204		230
205	initialise_node "locahost:4044";	231	initialise_node "localhost:4044";
206
207	Example: become a slave node to any of the specified master servers.
208
209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
210		232
211	=item $cv = resolve_node $noderef	233	=item $cv = resolve_node $noderef
212		234
213	Takes an unresolved node reference that may contain hostnames and	235	Takes an unresolved node reference that may contain hostnames and
214	abbreviated IDs, resolves all of them and returns a resolved node	236	abbreviated IDs, resolves all of them and returns a resolved node
…		…
251	=item snd $port, type => @data	273	=item snd $port, type => @data
252		274
253	=item snd $port, @msg	275	=item snd $port, @msg
254		276
255	Send the given message to the given port ID, which can identify either	277	Send the given message to the given port ID, which can identify either
256	a local or a remote port, and can be either a string or soemthignt hat	278	a local or a remote port, and must be a port ID.
257	stringifies a sa port ID (such as a port object :).
258		279
259	While the message can be about anything, it is highly recommended to use a	280	While the message can be about anything, it is highly recommended to use a
260	string as first element (a portid, or some word that indicates a request	281	string as first element (a port ID, or some word that indicates a request
261	type etc.).	282	type etc.).
262		283
263	The message data effectively becomes read-only after a call to this	284	The message data effectively becomes read-only after a call to this
264	function: modifying any argument is not allowed and can cause many	285	function: modifying any argument is not allowed and can cause many
265	problems.	286	problems.
…		…
270	that Storable can serialise and deserialise is allowed, and for the local	291	that Storable can serialise and deserialise is allowed, and for the local
271	node, anything can be passed.	292	node, anything can be passed.
272		293
273	=item $local_port = port	294	=item $local_port = port
274		295
275	Create a new local port object that can be used either as a pattern	296	Create a new local port object and returns its port ID. Initially it has
276	matching port ("full port") or a single-callback port ("miniport"),	297	no callbacks set and will throw an error when it receives messages.
277	depending on how C<rcv> callbacks are bound to the object.
278		298
279	=item $port = port { my @msg = @_; $finished }	299	=item $local_port = port { my @msg = @_ }
280		300
281	Creates a "miniport", that is, a very lightweight port without any pattern	301	Creates a new local port, and returns its ID. Semantically the same as
282	matching behind it, and returns its ID. Semantically the same as creating
283	a port and calling C<rcv $port, $callback> on it.	302	creating a port and calling C<rcv $port, $callback> on it.
284		303
285	The block will be called for every message received on the port. When the	304	The block will be called for every message received on the port, with the
286	callback returns a true value its job is considered "done" and the port	305	global variable C<$SELF> set to the port ID. Runtime errors will cause the
287	will be destroyed. Otherwise it will stay alive.	306	port to be C<kil>ed. The message will be passed as-is, no extra argument
		307	(i.e. no port ID) will be passed to the callback.
288		308
289	The message will be passed as-is, no extra argument (i.e. no port id) will	309	If you want to stop/destroy the port, simply C<kil> it:
290	be passed to the callback.
291		310
292	If you need the local port id in the callback, this works nicely:	311	my $port = port {
293		312	my @msg = @_;
294	my $port; $port = port {	313	...
295	snd $otherport, reply => $port;	314	kil $SELF;
296	};	315	};
297		316
298	=cut	317	=cut
299		318
300	sub rcv($@);	319	sub rcv($@);
		320
		321	sub _kilme {
		322	die "received message on port without callback";
		323	}
301		324
302	sub port(;&) {	325	sub port(;&) {
303	my $id = "$UNIQ." . $ID++;	326	my $id = "$UNIQ." . $ID++;
304	my $port = "$NODE#$id";	327	my $port = "$NODE#$id";
305		328
306	if (@_) {	329	rcv $port, shift \|\| \&_kilme;
307	rcv $port, shift;
308	} else {
309	$PORT{$id} = sub { }; # nop
310	}
311		330
312	$port	331	$port
313	}	332	}
314		333
315	=item reg $port, $name
316
317	=item reg $name
318
319	Registers the given port (or C<$SELF><<< if missing) under the name
320	C<$name>. If the name already exists it is replaced.
321
322	A port can only be registered under one well known name.
323
324	A port automatically becomes unregistered when it is killed.
325
326	=cut
327
328	sub reg(@) {
329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
330
331	$REG{$_[0]} = $port;
332	}
333
334	=item rcv $port, $callback->(@msg)	334	=item rcv $local_port, $callback->(@msg)
335		335
336	Replaces the callback on the specified miniport (after converting it to	336	Replaces the default callback on the specified port. There is no way to
337	one if required).	337	remove the default callback: use C<sub { }> to disable it, or better
338		338	C<kil> the port when it is no longer needed.
339	=item rcv $port, tagstring => $callback->(@msg), ...
340
341	=item rcv $port, $smartmatch => $callback->(@msg), ...
342
343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given full
346	port (after converting it to one if required) and return the port.
347
348	The callback has to return a true value when its work is done, after
349	which is will be removed, or a false value in which case it will stay
350	registered.
351		339
352	The global C<$SELF> (exported by this module) contains C<$port> while	340	The global C<$SELF> (exported by this module) contains C<$port> while
353	executing the callback.	341	executing the callback. Runtime errors during callback execution will
		342	result in the port being C<kil>ed.
354		343
355	Runtime errors during callback execution will result in the port being	344	The default callback received all messages not matched by a more specific
356	C<kil>ed.	345	C<tag> match.
357		346
358	If the match is an array reference, then it will be matched against the	347	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
359	first elements of the message, otherwise only the first element is being
360	matched.
361		348
362	Any element in the match that is specified as C<_any_> (a function	349	Register (or replace) callbacks to be called on messages starting with the
363	exported by this module) matches any single element of the message.	350	given tag on the given port (and return the port), or unregister it (when
		351	C<$callback> is C<$undef> or missing). There can only be one callback
		352	registered for each tag.
364		353
365	While not required, it is highly recommended that the first matching	354	The original message will be passed to the callback, after the first
366	element is a string identifying the message. The one-string-only match is	355	element (the tag) has been removed. The callback will use the same
367	also the most efficient match (by far).	356	environment as the default callback (see above).
368		357
369	Example: create a port and bind receivers on it in one go.	358	Example: create a port and bind receivers on it in one go.
370		359
371	my $port = rcv port,	360	my $port = rcv port,
372	msg1 => sub { ...; 0 },	361	msg1 => sub { ... },
373	msg2 => sub { ...; 0 },	362	msg2 => sub { ... },
374	;	363	;
375		364
376	Example: create a port, bind receivers and send it in a message elsewhere	365	Example: create a port, bind receivers and send it in a message elsewhere
377	in one go:	366	in one go:
378		367
379	snd $otherport, reply =>	368	snd $otherport, reply =>
380	rcv port,	369	rcv port,
381	msg1 => sub { ...; 0 },	370	msg1 => sub { ... },
382	...	371	...
383	;	372	;
		373
		374	Example: temporarily register a rcv callback for a tag matching some port
		375	(e.g. for a rpc reply) and unregister it after a message was received.
		376
		377	rcv $port, $otherport => sub {
		378	my @reply = @_;
		379
		380	rcv $SELF, $otherport;
		381	};
384		382
385	=cut	383	=cut
386		384
387	sub rcv($@) {	385	sub rcv($@) {
388	my $port = shift;	386	my $port = shift;
389	my ($noderef, $portid) = split /#/, $port, 2;	387	my ($noderef, $portid) = split /#/, $port, 2;
390		388
391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	389	$NODE{$noderef} == $NODE{""}
392	or Carp::croak "$port: rcv can only be called on local ports, caught";	390	or Carp::croak "$port: rcv can only be called on local ports, caught";
393		391
394	if (@_ == 1) {	392	while (@_) {
		393	if (ref $_[0]) {
		394	if (my $self = $PORT_DATA{$portid}) {
		395	"AnyEvent::MP::Port" eq ref $self
		396	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		397
		398	$self->[2] = shift;
		399	} else {
395	my $cb = shift;	400	my $cb = shift;
396	delete $PORT_DATA{$portid};
397	$PORT{$portid} = sub {	401	$PORT{$portid} = sub {
398	local $SELF = $port;	402	local $SELF = $port;
399	eval {	403	eval { &$cb }; _self_die if $@;
400	&$cb	404	};
401	and kil $port;
402	};	405	}
403	_self_die if $@;	406	} elsif (defined $_[0]) {
404	};
405	} else {
406	my $self = $PORT_DATA{$portid} \|\|= do {	407	my $self = $PORT_DATA{$portid} \|\|= do {
407	my $self = bless {	408	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
408	id => $port,
409	}, "AnyEvent::MP::Port";
410		409
411	$PORT{$portid} = sub {	410	$PORT{$portid} = sub {
412	local $SELF = $port;	411	local $SELF = $port;
413		412
414	eval {
415	for (@{ $self->{rc0}{$_[0]} }) {	413	if (my $cb = $self->[1]{$_[0]}) {
416	$_ && &{$_->[0]}	414	shift;
417	&& undef $_;	415	eval { &$cb }; _self_die if $@;
418	}	416	} else {
419
420	for (@{ $self->{rcv}{$_[0]} }) {
421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
422	&& &{$_->[0]}	417	&{ $self->[0] };
423	&& undef $_;
424	}
425
426	for (@{ $self->{any} }) {
427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
428	&& &{$_->[0]}
429	&& undef $_;
430	}	418	}
431	};	419	};
432	_self_die if $@;	420
		421	$self
433	};	422	};
434		423
435	$self
436	};
437
438	"AnyEvent::MP::Port" eq ref $self	424	"AnyEvent::MP::Port" eq ref $self
439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	425	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
440		426
441	while (@_) {
442	my ($match, $cb) = splice @_, 0, 2;	427	my ($tag, $cb) = splice @_, 0, 2;
443		428
444	if (!ref $match) {	429	if (defined $cb) {
445	push @{ $self->{rc0}{$match} }, [$cb];	430	$self->[1]{$tag} = $cb;
446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
447	my ($type, @match) = @$match;
448	@match
449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
451	} else {	431	} else {
452	push @{ $self->{any} }, [$cb, $match];	432	delete $self->[1]{$tag};
453	}	433	}
454	}	434	}
455	}	435	}
456		436
457	$port	437	$port
…		…
501		481
502	=item $guard = mon $port	482	=item $guard = mon $port
503		483
504	=item $guard = mon $port, $rcvport, @msg	484	=item $guard = mon $port, $rcvport, @msg
505		485
506	Monitor the given port and do something when the port is killed, and	486	Monitor the given port and do something when the port is killed or
507	optionally return a guard that can be used to stop monitoring again.	487	messages to it were lost, and optionally return a guard that can be used
		488	to stop monitoring again.
		489
		490	C<mon> effectively guarantees that, in the absence of hardware failures,
		491	that after starting the monitor, either all messages sent to the port
		492	will arrive, or the monitoring action will be invoked after possible
		493	message loss has been detected. No messages will be lost "in between"
		494	(after the first lost message no further messages will be received by the
		495	port). After the monitoring action was invoked, further messages might get
		496	delivered again.
		497
		498	Note that monitoring-actions are one-shot: once released, they are removed
		499	and will not trigger again.
508		500
509	In the first form (callback), the callback is simply called with any	501	In the first form (callback), the callback is simply called with any
510	number of C<@reason> elements (no @reason means that the port was deleted	502	number of C<@reason> elements (no @reason means that the port was deleted
511	"normally"). Note also that I<< the callback B<must> never die >>, so use	503	"normally"). Note also that I<< the callback B<must> never die >>, so use
512	C<eval> if unsure.	504	C<eval> if unsure.
513		505
514	In the second form (another port given), the other port (C<$rcvport)	506	In the second form (another port given), the other port (C<$rcvport>)
515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	507	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
516	"normal" kils nothing happens, while under all other conditions, the other	508	"normal" kils nothing happens, while under all other conditions, the other
517	port is killed with the same reason.	509	port is killed with the same reason.
518		510
519	The third form (kill self) is the same as the second form, except that	511	The third form (kill self) is the same as the second form, except that
…		…
546	sub mon {	538	sub mon {
547	my ($noderef, $port) = split /#/, shift, 2;	539	my ($noderef, $port) = split /#/, shift, 2;
548		540
549	my $node = $NODE{$noderef} \|\| add_node $noderef;	541	my $node = $NODE{$noderef} \|\| add_node $noderef;
550		542
551	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	543	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
552		544
553	unless (ref $cb) {	545	unless (ref $cb) {
554	if (@_) {	546	if (@_) {
555	# send a kill info message	547	# send a kill info message
556	my (@msg) = @_;	548	my (@msg) = ($cb, @_);
557	$cb = sub { snd @msg, @_ };	549	$cb = sub { snd @msg, @_ };
558	} else {	550	} else {
559	# simply kill other port	551	# simply kill other port
560	my $port = $cb;	552	my $port = $cb;
561	$cb = sub { kil $port, @_ if @_ };	553	$cb = sub { kil $port, @_ if @_ };
…		…
673	my $id = "$RUNIQ." . $ID++;	665	my $id = "$RUNIQ." . $ID++;
674		666
675	$_[0] =~ /::/	667	$_[0] =~ /::/
676	or Carp::croak "spawn init function must be a fully-qualified name, caught";	668	or Carp::croak "spawn init function must be a fully-qualified name, caught";
677		669
678	($NODE{$noderef} \|\| add_node $noderef)	670	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
679	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
680		671
681	"$noderef#$id"	672	"$noderef#$id"
682	}	673	}
683		674
684	=back	675	=item after $timeout, @msg
685		676
686	=head1 NODE MESSAGES	677	=item after $timeout, $callback
687		678
688	Nodes understand the following messages sent to them. Many of them take	679	Either sends the given message, or call the given callback, after the
689	arguments called C<@reply>, which will simply be used to compose a reply	680	specified number of seconds.
690	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
691	the remaining arguments are simply the message data.
692		681
693	While other messages exist, they are not public and subject to change.	682	This is simply a utility function that come sin handy at times.
694		683
695	=over 4
696
697	=cut	684	=cut
698		685
699	=item lookup => $name, @reply	686	sub after($@) {
		687	my ($timeout, @action) = @_;
700		688
701	Replies with the port ID of the specified well-known port, or C<undef>.	689	my $t; $t = AE::timer $timeout, 0, sub {
702		690	undef $t;
703	=item devnull => ...	691	ref $action[0]
704		692	? $action[0]()
705	Generic data sink/CPU heat conversion.	693	: snd @action;
706		694	};
707	=item relay => $port, @msg	695	}
708
709	Simply forwards the message to the given port.
710
711	=item eval => $string[ @reply]
712
713	Evaluates the given string. If C<@reply> is given, then a message of the
714	form C<@reply, $@, @evalres> is sent.
715
716	Example: crash another node.
717
718	snd $othernode, eval => "exit";
719
720	=item time => @reply
721
722	Replies the the current node time to C<@reply>.
723
724	Example: tell the current node to send the current time to C<$myport> in a
725	C<timereply> message.
726
727	snd $NODE, time => $myport, timereply => 1, 2;
728	# => snd $myport, timereply => 1, 2, <time>
729		696
730	=back	697	=back
731		698
732	=head1 AnyEvent::MP vs. Distributed Erlang	699	=head1 AnyEvent::MP vs. Distributed Erlang
733		700
…		…
752	convenience functionality.	719	convenience functionality.
753		720
754	This means that AEMP requires a less tightly controlled environment at the	721	This means that AEMP requires a less tightly controlled environment at the
755	cost of longer node references and a slightly higher management overhead.	722	cost of longer node references and a slightly higher management overhead.
756		723
		724	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
		725	uses "local ports are like remote ports".
		726
		727	The failure modes for local ports are quite different (runtime errors
		728	only) then for remote ports - when a local port dies, you I<know> it dies,
		729	when a connection to another node dies, you know nothing about the other
		730	port.
		731
		732	Erlang pretends remote ports are as reliable as local ports, even when
		733	they are not.
		734
		735	AEMP encourages a "treat remote ports differently" philosophy, with local
		736	ports being the special case/exception, where transport errors cannot
		737	occur.
		738
757	=item * Erlang uses processes and a mailbox, AEMP does not queue.	739	=item * Erlang uses processes and a mailbox, AEMP does not queue.
758		740
759	Erlang uses processes that selctively receive messages, and therefore	741	Erlang uses processes that selectively receive messages, and therefore
760	needs a queue. AEMP is event based, queuing messages would serve no useful	742	needs a queue. AEMP is event based, queuing messages would serve no
761	purpose.	743	useful purpose. For the same reason the pattern-matching abilities of
		744	AnyEvent::MP are more limited, as there is little need to be able to
		745	filter messages without dequeing them.
762		746
763	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	747	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
764		748
765	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	749	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
766		750
767	Sending messages in Erlang is synchronous and blocks the process. AEMP	751	Sending messages in Erlang is synchronous and blocks the process (and
768	sends are immediate, connection establishment is handled in the	752	so does not need a queue that can overflow). AEMP sends are immediate,
769	background.	753	connection establishment is handled in the background.
770		754
771	=item * Erlang can silently lose messages, AEMP cannot.	755	=item * Erlang suffers from silent message loss, AEMP does not.
772		756
773	Erlang makes few guarantees on messages delivery - messages can get lost	757	Erlang makes few guarantees on messages delivery - messages can get lost
774	without any of the processes realising it (i.e. you send messages a, b,	758	without any of the processes realising it (i.e. you send messages a, b,
775	and c, and the other side only receives messages a and c).	759	and c, and the other side only receives messages a and c).
776		760
…		…
788	eventually be killed - it cannot happen that a node detects a port as dead	772	eventually be killed - it cannot happen that a node detects a port as dead
789	and then later sends messages to it, finding it is still alive.	773	and then later sends messages to it, finding it is still alive.
790		774
791	=item * Erlang can send messages to the wrong port, AEMP does not.	775	=item * Erlang can send messages to the wrong port, AEMP does not.
792		776
793	In Erlang it is quite possible that a node that restarts reuses a process	777	In Erlang it is quite likely that a node that restarts reuses a process ID
794	ID known to other nodes for a completely different process, causing	778	known to other nodes for a completely different process, causing messages
795	messages destined for that process to end up in an unrelated process.	779	destined for that process to end up in an unrelated process.
796		780
797	AEMP never reuses port IDs, so old messages or old port IDs floating	781	AEMP never reuses port IDs, so old messages or old port IDs floating
798	around in the network will not be sent to an unrelated port.	782	around in the network will not be sent to an unrelated port.
799		783
800	=item * Erlang uses unprotected connections, AEMP uses secure	784	=item * Erlang uses unprotected connections, AEMP uses secure
…		…
836	This also saves round-trips and avoids sending messages to the wrong port	820	This also saves round-trips and avoids sending messages to the wrong port
837	(hard to do in Erlang).	821	(hard to do in Erlang).
838		822
839	=back	823	=back
840		824
		825	=head1 RATIONALE
		826
		827	=over 4
		828
		829	=item Why strings for ports and noderefs, why not objects?
		830
		831	We considered "objects", but found that the actual number of methods
		832	thatc an be called are very low. Since port IDs and noderefs travel over
		833	the network frequently, the serialising/deserialising would add lots of
		834	overhead, as well as having to keep a proxy object.
		835
		836	Strings can easily be printed, easily serialised etc. and need no special
		837	procedures to be "valid".
		838
		839	And a a miniport consists of a single closure stored in a global hash - it
		840	can't become much cheaper.
		841
		842	=item Why favour JSON, why not real serialising format such as Storable?
		843
		844	In fact, any AnyEvent::MP node will happily accept Storable as framing
		845	format, but currently there is no way to make a node use Storable by
		846	default.
		847
		848	The default framing protocol is JSON because a) JSON::XS is many times
		849	faster for small messages and b) most importantly, after years of
		850	experience we found that object serialisation is causing more problems
		851	than it gains: Just like function calls, objects simply do not travel
		852	easily over the network, mostly because they will always be a copy, so you
		853	always have to re-think your design.
		854
		855	Keeping your messages simple, concentrating on data structures rather than
		856	objects, will keep your messages clean, tidy and efficient.
		857
		858	=back
		859
841	=head1 SEE ALSO	860	=head1 SEE ALSO
842		861
843	L<AnyEvent>.	862	L<AnyEvent>.
844		863
845	=head1 AUTHOR	864	=head1 AUTHOR

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs. Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs.
Revision 1.62 by root, Thu Aug 27 07:12:48 2009 UTC