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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC vs.
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent::MP - multi-processing/message-passing framework	3	AnyEvent::MP - erlang-style multi-processing/message-passing framework
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
15	# initialise the node so it can send/receive messages	14	# initialise the node so it can send/receive messages
16	initialise_node;	15	configure;
17		16
18	# ports are message endpoints	17	# ports are message destinations
19		18
20	# sending messages	19	# sending messages
21	snd $port, type => data...;	20	snd $port, type => data...;
22	snd $port, @msg;	21	snd $port, @msg;
23	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
24		23
25	# creating/using ports, the simple way	24	# creating/using ports, the simple way
26	my $simple_port = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
27		26
28	# creating/using ports, tagged message matching	27	# creating/using ports, tagged message matching
29	my $port = port;	28	my $port = port;
30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
31	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
32		31
33	# create a port on another node	32	# create a port on another node
34	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
35		34
		35	# destroy a prot again
		36	kil $port; # "normal" kill
		37	kil $port, my_error => "everything is broken"; # error kill
		38
36	# monitoring	39	# monitoring
37	mon $port, $cb->(@msg) # callback is invoked on death	40	mon $localport, $cb->(@msg) # callback is invoked on death
38	mon $port, $otherport # kill otherport on abnormal death	41	mon $localport, $otherport # kill otherport on abnormal death
39	mon $port, $otherport, @msg # send message on death	42	mon $localport, $otherport, @msg # send message on death
		43
		44	# temporarily execute code in port context
		45	peval $port, sub { die "kill the port!" };
		46
		47	# execute callbacks in $SELF port context
		48	my $timer = AE::timer 1, 0, psub {
		49	die "kill the port, delayed";
		50	};
40		51
41	=head1 CURRENT STATUS	52	=head1 CURRENT STATUS
42		53
		54	bin/aemp - stable.
43	AnyEvent::MP - stable API, should work	55	AnyEvent::MP - stable API, should work.
44	AnyEvent::MP::Intro - outdated	56	AnyEvent::MP::Intro - explains most concepts.
45	AnyEvent::MP::Kernel - mostly stable	57	AnyEvent::MP::Kernel - mostly stable API.
46	AnyEvent::MP::Global - mostly stable	58	AnyEvent::MP::Global - stable API.
47	AnyEvent::MP::Node - mostly stable, but internal anyways
48	AnyEvent::MP::Transport - mostly stable, but internal anyways
49
50	stay tuned.
51		59
52	=head1 DESCRIPTION	60	=head1 DESCRIPTION
53		61
54	This module (-family) implements a simple message passing framework.	62	This module (-family) implements a simple message passing framework.
55		63
57	on the same or other hosts, and you can supervise entities remotely.	65	on the same or other hosts, and you can supervise entities remotely.
58		66
59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	67	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
60	manual page and the examples under F<eg/>.	68	manual page and the examples under F<eg/>.
61		69
62	At the moment, this module family is a bit underdocumented.
63
64	=head1 CONCEPTS	70	=head1 CONCEPTS
65		71
66	=over 4	72	=over 4
67		73
68	=item port	74	=item port
69		75
70	A port is something you can send messages to (with the C<snd> function).	76	Not to be confused with a TCP port, a "port" is something you can send
		77	messages to (with the C<snd> function).
71		78
72	Ports allow you to register C<rcv> handlers that can match all or just	79	Ports allow you to register C<rcv> handlers that can match all or just
73	some messages. Messages send to ports will not be queued, regardless of	80	some messages. Messages send to ports will not be queued, regardless of
74	anything was listening for them or not.	81	anything was listening for them or not.
75		82
…		…
86		93
87	Nodes are either public (have one or more listening ports) or private	94	Nodes are either public (have one or more listening ports) or private
88	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
89	currently.	96	currently.
90		97
91	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
92		99
93	A node ID is a string that uniquely identifies the node within a	100	A node ID is a string that uniquely identifies the node within a
94	network. Depending on the configuration used, node IDs can look like a	101	network. Depending on the configuration used, node IDs can look like a
95	hostname, a hostname and a port, or a random string. AnyEvent::MP itself	102	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
96	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
100	Nodes can only talk to each other by creating some kind of connection to	107	Nodes can only talk to each other by creating some kind of connection to
101	each other. To do this, nodes should listen on one or more local transport	108	each other. To do this, nodes should listen on one or more local transport
102	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
103	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
104		111
105	=item seeds - C<host:port>	112	=item seed nodes
106		113
107	When a node starts, it knows nothing about the network. To teach the node	114	When a node starts, it knows nothing about the network. To teach the node
108	about the network it first has to contact some other node within the	115	about the network it first has to contact some other node within the
109	network. This node is called a seed.	116	network. This node is called a seed.
110		117
111	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes	118	Apart from the fact that other nodes know them as seed nodes and they have
		119	to have fixed listening addresses, seed nodes are perfectly normal nodes -
		120	any node can function as a seed node for others.
		121
		122	In addition to discovering the network, seed nodes are also used to
		123	maintain the network and to connect nodes that otherwise would have
		124	trouble connecting. They form the backbone of an AnyEvent::MP network.
		125
112	are expected to be long-running, and at least one of those should always	126	Seed nodes are expected to be long-running, and at least one seed node
113	be available. When nodes run out of connections (e.g. due to a network	127	should always be available. They should also be relatively responsive - a
114	error), they try to re-establish connections to some seednodes again to	128	seed node that blocks for long periods will slow down everybody else.
115	join the network.
116		129
117	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
118	every public node can be a seednode.	131
		132	Seeds are transport endpoint(s) (usually a hostname/IP address and a
		133	TCP port) of nodes that should be used as seed nodes.
		134
		135	The nodes listening on those endpoints are expected to be long-running,
		136	and at least one of those should always be available. When nodes run out
		137	of connections (e.g. due to a network error), they try to re-establish
		138	connections to some seednodes again to join the network.
119		139
120	=back	140	=back
121		141
122	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
123		143
…		…
135		155
136	use AE ();	156	use AE ();
137		157
138	use base "Exporter";	158	use base "Exporter";
139		159
140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.24;
141		161
142	our @EXPORT = qw(	162	our @EXPORT = qw(
143	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
144	initialise_node	164	configure
145	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
146	port	166	port
147	);	167	);
148		168
149	our $SELF;	169	our $SELF;
150		170
…		…
156		176
157	=item $thisnode = NODE / $NODE	177	=item $thisnode = NODE / $NODE
158		178
159	The C<NODE> function returns, and the C<$NODE> variable contains, the node	179	The C<NODE> function returns, and the C<$NODE> variable contains, the node
160	ID of the node running in the current process. This value is initialised by	180	ID of the node running in the current process. This value is initialised by
161	a call to C<initialise_node>.	181	a call to C<configure>.
162		182
163	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
164		184
165	Extracts and returns the node ID from a port ID or a node ID.	185	Extracts and returns the node ID from a port ID or a node ID.
166		186
167	=item initialise_node $profile_name, key => value...	187	=item configure $profile, key => value...
		188
		189	=item configure key => value...
168		190
169	Before a node can talk to other nodes on the network (i.e. enter	191	Before a node can talk to other nodes on the network (i.e. enter
170	"distributed mode") it has to initialise itself - the minimum a node needs	192	"distributed mode") it has to configure itself - the minimum a node needs
171	to know is its own name, and optionally it should know the addresses of	193	to know is its own name, and optionally it should know the addresses of
172	some other nodes in the network to discover other nodes.	194	some other nodes in the network to discover other nodes.
173		195
174	This function initialises a node - it must be called exactly once (or	196	This function configures a node - it must be called exactly once (or
175	never) before calling other AnyEvent::MP functions.	197	never) before calling other AnyEvent::MP functions.
176		198
177	The first argument is a profile name. If it is C<undef> or missing, then	199	=over 4
178	the current nodename will be used instead (i.e. F<uname -n>).
179		200
		201	=item step 1, gathering configuration from profiles
		202
180	The function first looks up the profile in the aemp configuration (see the	203	The function first looks up a profile in the aemp configuration (see the
181	L<aemp> commandline utility). the profile is calculated as follows:	204	L<aemp> commandline utility). The profile name can be specified via the
		205	named C<profile> parameter or can simply be the first parameter). If it is
		206	missing, then the nodename (F<uname -n>) will be used as profile name.
182		207
183	First, all remaining key => value pairs will be used. Then they will be	208	The profile data is then gathered as follows:
184	overwritten by any values specified in the global default configuration	209
185	(see the F<aemp> utility), then the chain of profiles selected, if	210	First, all remaining key => value pairs (all of which are conveniently
		211	undocumented at the moment) will be interpreted as configuration
		212	data. Then they will be overwritten by any values specified in the global
		213	default configuration (see the F<aemp> utility), then the chain of
		214	profiles chosen by the profile name (and any C<parent> attributes).
		215
186	any. That means that the values specified in the profile have highest	216	That means that the values specified in the profile have highest priority
187	priority and the values specified via C<initialise_node> have lowest	217	and the values specified directly via C<configure> have lowest priority,
188	priority.	218	and can only be used to specify defaults.
189		219
190	If the profile specifies a node ID, then this will become the node ID of	220	If the profile specifies a node ID, then this will become the node ID of
191	this process. If not, then the profile name will be used as node ID. The	221	this process. If not, then the profile name will be used as node ID. The
192	special node ID of C<anon/> will be replaced by a random node ID.	222	special node ID of C<anon/> will be replaced by a random node ID.
		223
		224	=item step 2, bind listener sockets
193		225
194	The next step is to look up the binds in the profile, followed by binding	226	The next step is to look up the binds in the profile, followed by binding
195	aemp protocol listeners on all binds specified (it is possible and valid	227	aemp protocol listeners on all binds specified (it is possible and valid
196	to have no binds, meaning that the node cannot be contacted form the	228	to have no binds, meaning that the node cannot be contacted form the
197	outside. This means the node cannot talk to other nodes that also have no	229	outside. This means the node cannot talk to other nodes that also have no
198	binds, but it can still talk to all "normal" nodes).	230	binds, but it can still talk to all "normal" nodes).
199		231
200	If the profile does not specify a binds list, then the node ID will be	232	If the profile does not specify a binds list, then a default of C<*> is
201	treated as if it were of the form C<host:port>, which will be resolved and	233	used, meaning the node will bind on a dynamically-assigned port on every
202	used as binds list.	234	local IP address it finds.
203		235
		236	=item step 3, connect to seed nodes
		237
204	Lastly, the seeds list from the profile is passed to the	238	As the last step, the seeds list from the profile is passed to the
205	L<AnyEvent::MP::Global> module, which will then use it to keep	239	L<AnyEvent::MP::Global> module, which will then use it to keep
206	connectivity with at least on of those seed nodes at any point in time.	240	connectivity with at least one node at any point in time.
207		241
208	Example: become a distributed node listening on the guessed noderef, or	242	=back
209	the one specified via C<aemp> for the current node. This should be the	243
		244	Example: become a distributed node using the local node name as profile.
210	most common form of invocation for "daemon"-type nodes.	245	This should be the most common form of invocation for "daemon"-type nodes.
211		246
212	initialise_node;	247	configure
213		248
214	Example: become an anonymous node. This form is often used for commandline	249	Example: become an anonymous node. This form is often used for commandline
215	clients.	250	clients.
216		251
217	initialise_node "anon/";	252	configure nodeid => "anon/";
218		253
219	Example: become a distributed node. If there is no profile of the given	254	Example: configure a node using a profile called seed, which si suitable
220	name, or no binds list was specified, resolve C<localhost:4044> and bind	255	for a seed node as it binds on all local addresses on a fixed port (4040,
221	on the resulting addresses.	256	customary for aemp).
222		257
223	initialise_node "localhost:4044";	258	# use the aemp commandline utility
		259	# aemp profile seed nodeid anon/ binds '*:4040'
		260
		261	# then use it
		262	configure profile => "seed";
		263
		264	# or simply use aemp from the shell again:
		265	# aemp run profile seed
		266
		267	# or provide a nicer-to-remember nodeid
		268	# aemp run profile seed nodeid "$(hostname)"
224		269
225	=item $SELF	270	=item $SELF
226		271
227	Contains the current port id while executing C<rcv> callbacks or C<psub>	272	Contains the current port id while executing C<rcv> callbacks or C<psub>
228	blocks.	273	blocks.
…		…
338	msg1 => sub { ... },	383	msg1 => sub { ... },
339	...	384	...
340	;	385	;
341		386
342	Example: temporarily register a rcv callback for a tag matching some port	387	Example: temporarily register a rcv callback for a tag matching some port
343	(e.g. for a rpc reply) and unregister it after a message was received.	388	(e.g. for an rpc reply) and unregister it after a message was received.
344		389
345	rcv $port, $otherport => sub {	390	rcv $port, $otherport => sub {
346	my @reply = @_;	391	my @reply = @_;
347		392
348	rcv $SELF, $otherport;	393	rcv $SELF, $otherport;
…		…
350		395
351	=cut	396	=cut
352		397
353	sub rcv($@) {	398	sub rcv($@) {
354	my $port = shift;	399	my $port = shift;
355	my ($noderef, $portid) = split /#/, $port, 2;	400	my ($nodeid, $portid) = split /#/, $port, 2;
356		401
357	$NODE{$noderef} == $NODE{""}	402	$NODE{$nodeid} == $NODE{""}
358	or Carp::croak "$port: rcv can only be called on local ports, caught";	403	or Carp::croak "$port: rcv can only be called on local ports, caught";
359		404
360	while (@_) {	405	while (@_) {
361	if (ref $_[0]) {	406	if (ref $_[0]) {
362	if (my $self = $PORT_DATA{$portid}) {	407	if (my $self = $PORT_DATA{$portid}) {
363	"AnyEvent::MP::Port" eq ref $self	408	"AnyEvent::MP::Port" eq ref $self
364	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	409	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
365		410
366	$self->[2] = shift;	411	$self->[0] = shift;
367	} else {	412	} else {
368	my $cb = shift;	413	my $cb = shift;
369	$PORT{$portid} = sub {	414	$PORT{$portid} = sub {
370	local $SELF = $port;	415	local $SELF = $port;
371	eval { &$cb }; _self_die if $@;	416	eval { &$cb }; _self_die if $@;
372	};	417	};
373	}	418	}
374	} elsif (defined $_[0]) {	419	} elsif (defined $_[0]) {
375	my $self = $PORT_DATA{$portid} \|\|= do {	420	my $self = $PORT_DATA{$portid} \|\|= do {
376	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	421	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
377		422
378	$PORT{$portid} = sub {	423	$PORT{$portid} = sub {
379	local $SELF = $port;	424	local $SELF = $port;
380		425
381	if (my $cb = $self->[1]{$_[0]}) {	426	if (my $cb = $self->[1]{$_[0]}) {
…		…
403	}	448	}
404		449
405	$port	450	$port
406	}	451	}
407		452
		453	=item peval $port, $coderef[, @args]
		454
		455	Evaluates the given C<$codref> within the contetx of C<$port>, that is,
		456	when the code throews an exception the C<$port> will be killed.
		457
		458	Any remaining args will be passed to the callback. Any return values will
		459	be returned to the caller.
		460
		461	This is useful when you temporarily want to execute code in the context of
		462	a port.
		463
		464	Example: create a port and run some initialisation code in it's context.
		465
		466	my $port = port { ... };
		467
		468	peval $port, sub {
		469	init
		470	or die "unable to init";
		471	};
		472
		473	=cut
		474
		475	sub peval($$) {
		476	local $SELF = shift;
		477	my $cb = shift;
		478
		479	if (wantarray) {
		480	my @res = eval { &$cb };
		481	_self_die if $@;
		482	@res
		483	} else {
		484	my $res = eval { &$cb };
		485	_self_die if $@;
		486	$res
		487	}
		488	}
		489
408	=item $closure = psub { BLOCK }	490	=item $closure = psub { BLOCK }
409		491
410	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	492	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
411	closure is executed, sets up the environment in the same way as in C<rcv>	493	closure is executed, sets up the environment in the same way as in C<rcv>
412	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.	494	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		495
		496	The effect is basically as if it returned C<< sub { peval $SELF, sub {
		497	BLOCK } } >>.
413		498
414	This is useful when you register callbacks from C<rcv> callbacks:	499	This is useful when you register callbacks from C<rcv> callbacks:
415		500
416	rcv delayed_reply => sub {	501	rcv delayed_reply => sub {
417	my ($delay, @reply) = @_;	502	my ($delay, @reply) = @_;
…		…
453		538
454	Monitor the given port and do something when the port is killed or	539	Monitor the given port and do something when the port is killed or
455	messages to it were lost, and optionally return a guard that can be used	540	messages to it were lost, and optionally return a guard that can be used
456	to stop monitoring again.	541	to stop monitoring again.
457		542
		543	In the first form (callback), the callback is simply called with any
		544	number of C<@reason> elements (no @reason means that the port was deleted
		545	"normally"). Note also that I<< the callback B<must> never die >>, so use
		546	C<eval> if unsure.
		547
		548	In the second form (another port given), the other port (C<$rcvport>)
		549	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
		550	"normal" kils nothing happens, while under all other conditions, the other
		551	port is killed with the same reason.
		552
		553	The third form (kill self) is the same as the second form, except that
		554	C<$rvport> defaults to C<$SELF>.
		555
		556	In the last form (message), a message of the form C<@msg, @reason> will be
		557	C<snd>.
		558
		559	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		560	alert was raised), they are removed and will not trigger again.
		561
		562	As a rule of thumb, monitoring requests should always monitor a port from
		563	a local port (or callback). The reason is that kill messages might get
		564	lost, just like any other message. Another less obvious reason is that
		565	even monitoring requests can get lost (for example, when the connection
		566	to the other node goes down permanently). When monitoring a port locally
		567	these problems do not exist.
		568
458	C<mon> effectively guarantees that, in the absence of hardware failures,	569	C<mon> effectively guarantees that, in the absence of hardware failures,
459	after starting the monitor, either all messages sent to the port will	570	after starting the monitor, either all messages sent to the port will
460	arrive, or the monitoring action will be invoked after possible message	571	arrive, or the monitoring action will be invoked after possible message
461	loss has been detected. No messages will be lost "in between" (after	572	loss has been detected. No messages will be lost "in between" (after
462	the first lost message no further messages will be received by the	573	the first lost message no further messages will be received by the
463	port). After the monitoring action was invoked, further messages might get	574	port). After the monitoring action was invoked, further messages might get
464	delivered again.	575	delivered again.
465		576
466	Note that monitoring-actions are one-shot: once messages are lost (and a	577	Inter-host-connection timeouts and monitoring depend on the transport
467	monitoring alert was raised), they are removed and will not trigger again.	578	used. The only transport currently implemented is TCP, and AnyEvent::MP
		579	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		580	non-idle connection, and usually around two hours for idle connections).
468		581
469	In the first form (callback), the callback is simply called with any	582	This means that monitoring is good for program errors and cleaning up
470	number of C<@reason> elements (no @reason means that the port was deleted	583	stuff eventually, but they are no replacement for a timeout when you need
471	"normally"). Note also that I<< the callback B<must> never die >>, so use	584	to ensure some maximum latency.
472	C<eval> if unsure.
473
474	In the second form (another port given), the other port (C<$rcvport>)
475	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
476	"normal" kils nothing happens, while under all other conditions, the other
477	port is killed with the same reason.
478
479	The third form (kill self) is the same as the second form, except that
480	C<$rvport> defaults to C<$SELF>.
481
482	In the last form (message), a message of the form C<@msg, @reason> will be
483	C<snd>.
484
485	As a rule of thumb, monitoring requests should always monitor a port from
486	a local port (or callback). The reason is that kill messages might get
487	lost, just like any other message. Another less obvious reason is that
488	even monitoring requests can get lost (for exmaple, when the connection
489	to the other node goes down permanently). When monitoring a port locally
490	these problems do not exist.
491		585
492	Example: call a given callback when C<$port> is killed.	586	Example: call a given callback when C<$port> is killed.
493		587
494	mon $port, sub { warn "port died because of <@_>\n" };	588	mon $port, sub { warn "port died because of <@_>\n" };
495		589
…		…
502	mon $port, $self => "restart";	596	mon $port, $self => "restart";
503		597
504	=cut	598	=cut
505		599
506	sub mon {	600	sub mon {
507	my ($noderef, $port) = split /#/, shift, 2;	601	my ($nodeid, $port) = split /#/, shift, 2;
508		602
509	my $node = $NODE{$noderef} \|\| add_node $noderef;	603	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
510		604
511	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	605	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
512		606
513	unless (ref $cb) {	607	unless (ref $cb) {
514	if (@_) {	608	if (@_) {
…		…
523	}	617	}
524		618
525	$node->monitor ($port, $cb);	619	$node->monitor ($port, $cb);
526		620
527	defined wantarray	621	defined wantarray
528	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	622	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
529	}	623	}
530		624
531	=item $guard = mon_guard $port, $ref, $ref...	625	=item $guard = mon_guard $port, $ref, $ref...
532		626
533	Monitors the given C<$port> and keeps the passed references. When the port	627	Monitors the given C<$port> and keeps the passed references. When the port
…		…
590	the package, then the package above the package and so on (e.g.	684	the package, then the package above the package and so on (e.g.
591	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	685	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
592	exists or it runs out of package names.	686	exists or it runs out of package names.
593		687
594	The init function is then called with the newly-created port as context	688	The init function is then called with the newly-created port as context
595	object (C<$SELF>) and the C<@initdata> values as arguments.	689	object (C<$SELF>) and the C<@initdata> values as arguments. It I<must>
		690	call one of the C<rcv> functions to set callbacks on C<$SELF>, otherwise
		691	the port might not get created.
596		692
597	A common idiom is to pass a local port, immediately monitor the spawned	693	A common idiom is to pass a local port, immediately monitor the spawned
598	port, and in the remote init function, immediately monitor the passed	694	port, and in the remote init function, immediately monitor the passed
599	local port. This two-way monitoring ensures that both ports get cleaned up	695	local port. This two-way monitoring ensures that both ports get cleaned up
600	when there is a problem.	696	when there is a problem.
601		697
		698	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		699	caller before C<spawn> returns (by delaying invocation when spawn is
		700	called for the local node).
		701
602	Example: spawn a chat server port on C<$othernode>.	702	Example: spawn a chat server port on C<$othernode>.
603		703
604	# this node, executed from within a port context:	704	# this node, executed from within a port context:
605	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	705	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
606	mon $server;	706	mon $server;
…		…
620		720
621	sub _spawn {	721	sub _spawn {
622	my $port = shift;	722	my $port = shift;
623	my $init = shift;	723	my $init = shift;
624		724
		725	# rcv will create the actual port
625	local $SELF = "$NODE#$port";	726	local $SELF = "$NODE#$port";
626	eval {	727	eval {
627	&{ load_func $init }	728	&{ load_func $init }
628	};	729	};
629	_self_die if $@;	730	_self_die if $@;
630	}	731	}
631		732
632	sub spawn(@) {	733	sub spawn(@) {
633	my ($noderef, undef) = split /#/, shift, 2;	734	my ($nodeid, undef) = split /#/, shift, 2;
634		735
635	my $id = "$RUNIQ." . $ID++;	736	my $id = "$RUNIQ." . $ID++;
636		737
637	$_[0] =~ /::/	738	$_[0] =~ /::/
638	or Carp::croak "spawn init function must be a fully-qualified name, caught";	739	or Carp::croak "spawn init function must be a fully-qualified name, caught";
639		740
640	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;	741	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
641		742
642	"$noderef#$id"	743	"$nodeid#$id"
643	}	744	}
644		745
645	=item after $timeout, @msg	746	=item after $timeout, @msg
646		747
647	=item after $timeout, $callback	748	=item after $timeout, $callback
…		…
664	? $action[0]()	765	? $action[0]()
665	: snd @action;	766	: snd @action;
666	};	767	};
667	}	768	}
668		769
		770	=item cal $port, @msg, $callback[, $timeout]
		771
		772	A simple form of RPC - sends a message to the given C<$port> with the
		773	given contents (C<@msg>), but adds a reply port to the message.
		774
		775	The reply port is created temporarily just for the purpose of receiving
		776	the reply, and will be C<kil>ed when no longer needed.
		777
		778	A reply message sent to the port is passed to the C<$callback> as-is.
		779
		780	If an optional time-out (in seconds) is given and it is not C<undef>,
		781	then the callback will be called without any arguments after the time-out
		782	elapsed and the port is C<kil>ed.
		783
		784	If no time-out is given (or it is C<undef>), then the local port will
		785	monitor the remote port instead, so it eventually gets cleaned-up.
		786
		787	Currently this function returns the temporary port, but this "feature"
		788	might go in future versions unless you can make a convincing case that
		789	this is indeed useful for something.
		790
		791	=cut
		792
		793	sub cal(@) {
		794	my $timeout = ref $_[-1] ? undef : pop;
		795	my $cb = pop;
		796
		797	my $port = port {
		798	undef $timeout;
		799	kil $SELF;
		800	&$cb;
		801	};
		802
		803	if (defined $timeout) {
		804	$timeout = AE::timer $timeout, 0, sub {
		805	undef $timeout;
		806	kil $port;
		807	$cb->();
		808	};
		809	} else {
		810	mon $_[0], sub {
		811	kil $port;
		812	$cb->();
		813	};
		814	}
		815
		816	push @_, $port;
		817	&snd;
		818
		819	$port
		820	}
		821
669	=back	822	=back
670		823
671	=head1 AnyEvent::MP vs. Distributed Erlang	824	=head1 AnyEvent::MP vs. Distributed Erlang
672		825
673	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	826	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
674	== aemp node, Erlang process == aemp port), so many of the documents and	827	== aemp node, Erlang process == aemp port), so many of the documents and
675	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	828	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
676	sample:	829	sample:
677		830
678	http://www.Erlang.se/doc/programming_rules.shtml	831	http://www.erlang.se/doc/programming_rules.shtml
679	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	832	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
680	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6	833	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
681	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	834	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
682		835
683	Despite the similarities, there are also some important differences:	836	Despite the similarities, there are also some important differences:
684		837
685	=over 4	838	=over 4
686		839
687	=item * Node IDs are arbitrary strings in AEMP.	840	=item * Node IDs are arbitrary strings in AEMP.
688		841
689	Erlang relies on special naming and DNS to work everywhere in the same	842	Erlang relies on special naming and DNS to work everywhere in the same
690	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by	843	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
691	configuraiton or DNS), but will otherwise discover other odes itself.	844	configuration or DNS), and possibly the addresses of some seed nodes, but
		845	will otherwise discover other nodes (and their IDs) itself.
692		846
693	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	847	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
694	uses "local ports are like remote ports".	848	uses "local ports are like remote ports".
695		849
696	The failure modes for local ports are quite different (runtime errors	850	The failure modes for local ports are quite different (runtime errors
…		…
709		863
710	Erlang uses processes that selectively receive messages, and therefore	864	Erlang uses processes that selectively receive messages, and therefore
711	needs a queue. AEMP is event based, queuing messages would serve no	865	needs a queue. AEMP is event based, queuing messages would serve no
712	useful purpose. For the same reason the pattern-matching abilities of	866	useful purpose. For the same reason the pattern-matching abilities of
713	AnyEvent::MP are more limited, as there is little need to be able to	867	AnyEvent::MP are more limited, as there is little need to be able to
714	filter messages without dequeing them.	868	filter messages without dequeuing them.
715		869
716	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	870	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
717		871
718	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	872	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
719		873
…		…
721	so does not need a queue that can overflow). AEMP sends are immediate,	875	so does not need a queue that can overflow). AEMP sends are immediate,
722	connection establishment is handled in the background.	876	connection establishment is handled in the background.
723		877
724	=item * Erlang suffers from silent message loss, AEMP does not.	878	=item * Erlang suffers from silent message loss, AEMP does not.
725		879
726	Erlang makes few guarantees on messages delivery - messages can get lost	880	Erlang implements few guarantees on messages delivery - messages can get
727	without any of the processes realising it (i.e. you send messages a, b,	881	lost without any of the processes realising it (i.e. you send messages a,
728	and c, and the other side only receives messages a and c).	882	b, and c, and the other side only receives messages a and c).
729		883
730	AEMP guarantees correct ordering, and the guarantee that after one message	884	AEMP guarantees correct ordering, and the guarantee that after one message
731	is lost, all following ones sent to the same port are lost as well, until	885	is lost, all following ones sent to the same port are lost as well, until
732	monitoring raises an error, so there are no silent "holes" in the message	886	monitoring raises an error, so there are no silent "holes" in the message
733	sequence.	887	sequence.
…		…
825	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	979	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
826		980
827	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	981	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
828	your applications.	982	your applications.
829		983
		984	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
		985
		986	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
		987	all nodes.
		988
830	L<AnyEvent>.	989	L<AnyEvent>.
831		990
832	=head1 AUTHOR	991	=head1 AUTHOR
833		992
834	Marc Lehmann <schmorp@schmorp.de>	993	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC vs.
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC