[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 1.114 by root, Thu Apr 22 16:06:19 2010 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 = 1.28;
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
		196	The key/value pairs are basically the same ones as documented for the
		197	F<aemp> command line utility (sans the set/del prefix).
		198
174	This function initialises a node - it must be called exactly once (or	199	This function configures a node - it must be called exactly once (or
175	never) before calling other AnyEvent::MP functions.	200	never) before calling other AnyEvent::MP functions.
176		201
177	The first argument is a profile name. If it is C<undef> or missing, then	202	=over 4
178	the current nodename will be used instead (i.e. F<uname -n>).
179		203
		204	=item step 1, gathering configuration from profiles
		205
180	The function first looks up the profile in the aemp configuration (see the	206	The function first looks up a profile in the aemp configuration (see the
181	L<aemp> commandline utility). the profile is calculated as follows:	207	L<aemp> commandline utility). The profile name can be specified via the
		208	named C<profile> parameter or can simply be the first parameter). If it is
		209	missing, then the nodename (F<uname -n>) will be used as profile name.
182		210
183	First, all remaining key => value pairs will be used. Then they will be	211	The profile data is then gathered as follows:
184	overwritten by any values specified in the global default configuration	212
185	(see the F<aemp> utility), then the chain of profiles selected, if	213	First, all remaining key => value pairs (all of which are conveniently
		214	undocumented at the moment) will be interpreted as configuration
		215	data. Then they will be overwritten by any values specified in the global
		216	default configuration (see the F<aemp> utility), then the chain of
		217	profiles chosen by the profile name (and any C<parent> attributes).
		218
186	any. That means that the values specified in the profile have highest	219	That means that the values specified in the profile have highest priority
187	priority and the values specified via C<initialise_node> have lowest	220	and the values specified directly via C<configure> have lowest priority,
188	priority.	221	and can only be used to specify defaults.
189		222
190	If the profile specifies a node ID, then this will become the node ID of	223	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	224	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.	225	special node ID of C<anon/> will be replaced by a random node ID.
		226
		227	=item step 2, bind listener sockets
193		228
194	The next step is to look up the binds in the profile, followed by binding	229	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	230	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	231	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	232	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).	233	binds, but it can still talk to all "normal" nodes).
199		234
200	If the profile does not specify a binds list, then the node ID will be	235	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	236	used, meaning the node will bind on a dynamically-assigned port on every
202	used as binds list.	237	local IP address it finds.
203		238
		239	=item step 3, connect to seed nodes
		240
204	Lastly, the seeds list from the profile is passed to the	241	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	242	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.	243	connectivity with at least one node at any point in time.
207		244
208	Example: become a distributed node listening on the guessed noderef, or	245	=back
209	the one specified via C<aemp> for the current node. This should be the	246
		247	Example: become a distributed node using the local node name as profile.
210	most common form of invocation for "daemon"-type nodes.	248	This should be the most common form of invocation for "daemon"-type nodes.
211		249
212	initialise_node;	250	configure
213		251
214	Example: become an anonymous node. This form is often used for commandline	252	Example: become an anonymous node. This form is often used for commandline
215	clients.	253	clients.
216		254
217	initialise_node "anon/";	255	configure nodeid => "anon/";
218		256
219	Example: become a distributed node. If there is no profile of the given	257	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	258	for a seed node as it binds on all local addresses on a fixed port (4040,
221	on the resulting addresses.	259	customary for aemp).
222		260
223	initialise_node "localhost:4044";	261	# use the aemp commandline utility
		262	# aemp profile seed nodeid anon/ binds '*:4040'
		263
		264	# then use it
		265	configure profile => "seed";
		266
		267	# or simply use aemp from the shell again:
		268	# aemp run profile seed
		269
		270	# or provide a nicer-to-remember nodeid
		271	# aemp run profile seed nodeid "$(hostname)"
224		272
225	=item $SELF	273	=item $SELF
226		274
227	Contains the current port id while executing C<rcv> callbacks or C<psub>	275	Contains the current port id while executing C<rcv> callbacks or C<psub>
228	blocks.	276	blocks.
…		…
338	msg1 => sub { ... },	386	msg1 => sub { ... },
339	...	387	...
340	;	388	;
341		389
342	Example: temporarily register a rcv callback for a tag matching some port	390	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.	391	(e.g. for an rpc reply) and unregister it after a message was received.
344		392
345	rcv $port, $otherport => sub {	393	rcv $port, $otherport => sub {
346	my @reply = @_;	394	my @reply = @_;
347		395
348	rcv $SELF, $otherport;	396	rcv $SELF, $otherport;
…		…
350		398
351	=cut	399	=cut
352		400
353	sub rcv($@) {	401	sub rcv($@) {
354	my $port = shift;	402	my $port = shift;
355	my ($noderef, $portid) = split /#/, $port, 2;	403	my ($nodeid, $portid) = split /#/, $port, 2;
356		404
357	$NODE{$noderef} == $NODE{""}	405	$NODE{$nodeid} == $NODE{""}
358	or Carp::croak "$port: rcv can only be called on local ports, caught";	406	or Carp::croak "$port: rcv can only be called on local ports, caught";
359		407
360	while (@_) {	408	while (@_) {
361	if (ref $_[0]) {	409	if (ref $_[0]) {
362	if (my $self = $PORT_DATA{$portid}) {	410	if (my $self = $PORT_DATA{$portid}) {
363	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
364	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	412	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
365		413
366	$self->[2] = shift;	414	$self->[0] = shift;
367	} else {	415	} else {
368	my $cb = shift;	416	my $cb = shift;
369	$PORT{$portid} = sub {	417	$PORT{$portid} = sub {
370	local $SELF = $port;	418	local $SELF = $port;
371	eval { &$cb }; _self_die if $@;	419	eval { &$cb }; _self_die if $@;
372	};	420	};
373	}	421	}
374	} elsif (defined $_[0]) {	422	} elsif (defined $_[0]) {
375	my $self = $PORT_DATA{$portid} \|\|= do {	423	my $self = $PORT_DATA{$portid} \|\|= do {
376	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	424	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
377		425
378	$PORT{$portid} = sub {	426	$PORT{$portid} = sub {
379	local $SELF = $port;	427	local $SELF = $port;
380		428
381	if (my $cb = $self->[1]{$_[0]}) {	429	if (my $cb = $self->[1]{$_[0]}) {
…		…
403	}	451	}
404		452
405	$port	453	$port
406	}	454	}
407		455
		456	=item peval $port, $coderef[, @args]
		457
		458	Evaluates the given C<$codref> within the contetx of C<$port>, that is,
		459	when the code throews an exception the C<$port> will be killed.
		460
		461	Any remaining args will be passed to the callback. Any return values will
		462	be returned to the caller.
		463
		464	This is useful when you temporarily want to execute code in the context of
		465	a port.
		466
		467	Example: create a port and run some initialisation code in it's context.
		468
		469	my $port = port { ... };
		470
		471	peval $port, sub {
		472	init
		473	or die "unable to init";
		474	};
		475
		476	=cut
		477
		478	sub peval($$) {
		479	local $SELF = shift;
		480	my $cb = shift;
		481
		482	if (wantarray) {
		483	my @res = eval { &$cb };
		484	_self_die if $@;
		485	@res
		486	} else {
		487	my $res = eval { &$cb };
		488	_self_die if $@;
		489	$res
		490	}
		491	}
		492
408	=item $closure = psub { BLOCK }	493	=item $closure = psub { BLOCK }
409		494
410	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	495	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>	496	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.	497	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		498
		499	The effect is basically as if it returned C<< sub { peval $SELF, sub {
		500	BLOCK }, @_ } >>.
413		501
414	This is useful when you register callbacks from C<rcv> callbacks:	502	This is useful when you register callbacks from C<rcv> callbacks:
415		503
416	rcv delayed_reply => sub {	504	rcv delayed_reply => sub {
417	my ($delay, @reply) = @_;	505	my ($delay, @reply) = @_;
…		…
453		541
454	Monitor the given port and do something when the port is killed or	542	Monitor the given port and do something when the port is killed or
455	messages to it were lost, and optionally return a guard that can be used	543	messages to it were lost, and optionally return a guard that can be used
456	to stop monitoring again.	544	to stop monitoring again.
457		545
		546	In the first form (callback), the callback is simply called with any
		547	number of C<@reason> elements (no @reason means that the port was deleted
		548	"normally"). Note also that I<< the callback B<must> never die >>, so use
		549	C<eval> if unsure.
		550
		551	In the second form (another port given), the other port (C<$rcvport>)
		552	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
		553	"normal" kils nothing happens, while under all other conditions, the other
		554	port is killed with the same reason.
		555
		556	The third form (kill self) is the same as the second form, except that
		557	C<$rvport> defaults to C<$SELF>.
		558
		559	In the last form (message), a message of the form C<@msg, @reason> will be
		560	C<snd>.
		561
		562	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		563	alert was raised), they are removed and will not trigger again.
		564
		565	As a rule of thumb, monitoring requests should always monitor a port from
		566	a local port (or callback). The reason is that kill messages might get
		567	lost, just like any other message. Another less obvious reason is that
		568	even monitoring requests can get lost (for example, when the connection
		569	to the other node goes down permanently). When monitoring a port locally
		570	these problems do not exist.
		571
458	C<mon> effectively guarantees that, in the absence of hardware failures,	572	C<mon> effectively guarantees that, in the absence of hardware failures,
459	after starting the monitor, either all messages sent to the port will	573	after starting the monitor, either all messages sent to the port will
460	arrive, or the monitoring action will be invoked after possible message	574	arrive, or the monitoring action will be invoked after possible message
461	loss has been detected. No messages will be lost "in between" (after	575	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	576	the first lost message no further messages will be received by the
463	port). After the monitoring action was invoked, further messages might get	577	port). After the monitoring action was invoked, further messages might get
464	delivered again.	578	delivered again.
465		579
466	Note that monitoring-actions are one-shot: once messages are lost (and a	580	Inter-host-connection timeouts and monitoring depend on the transport
467	monitoring alert was raised), they are removed and will not trigger again.	581	used. The only transport currently implemented is TCP, and AnyEvent::MP
		582	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		583	non-idle connection, and usually around two hours for idle connections).
468		584
469	In the first form (callback), the callback is simply called with any	585	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	586	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	587	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<$SELF>.
481
482	In the last form (message), a message of the form C<@msg, @reason> will be
483	C<snd>.
484
485	As a rule of thumb, monitoring requests should always monitor a port from
486	a local port (or callback). The reason is that kill messages might get
487	lost, just like any other message. Another less obvious reason is that
488	even monitoring requests can get lost (for exmaple, when the connection
489	to the other node goes down permanently). When monitoring a port locally
490	these problems do not exist.
491		588
492	Example: call a given callback when C<$port> is killed.	589	Example: call a given callback when C<$port> is killed.
493		590
494	mon $port, sub { warn "port died because of <@_>\n" };	591	mon $port, sub { warn "port died because of <@_>\n" };
495		592
…		…
502	mon $port, $self => "restart";	599	mon $port, $self => "restart";
503		600
504	=cut	601	=cut
505		602
506	sub mon {	603	sub mon {
507	my ($noderef, $port) = split /#/, shift, 2;	604	my ($nodeid, $port) = split /#/, shift, 2;
508		605
509	my $node = $NODE{$noderef} \|\| add_node $noderef;	606	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
510		607
511	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	608	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
512		609
513	unless (ref $cb) {	610	unless (ref $cb) {
514	if (@_) {	611	if (@_) {
…		…
523	}	620	}
524		621
525	$node->monitor ($port, $cb);	622	$node->monitor ($port, $cb);
526		623
527	defined wantarray	624	defined wantarray
528	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	625	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
529	}	626	}
530		627
531	=item $guard = mon_guard $port, $ref, $ref...	628	=item $guard = mon_guard $port, $ref, $ref...
532		629
533	Monitors the given C<$port> and keeps the passed references. When the port	630	Monitors the given C<$port> and keeps the passed references. When the port
…		…
556		653
557	=item kil $port[, @reason]	654	=item kil $port[, @reason]
558		655
559	Kill the specified port with the given C<@reason>.	656	Kill the specified port with the given C<@reason>.
560		657
561	If no C<@reason> is specified, then the port is killed "normally" (ports	658	If no C<@reason> is specified, then the port is killed "normally" -
562	monitoring other ports will not necessarily die because a port dies	659	monitor callback will be invoked, but the kil will not cause linked ports
563	"normally").	660	(C<mon $mport, $lport> form) to get killed.
564		661
565	Otherwise, linked ports get killed with the same reason (second form of	662	If a C<@reason> is specified, then linked ports (C<mon $mport, $lport>
566	C<mon>, see above).	663	form) get killed with the same reason.
567		664
568	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	665	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
569	will be reported as reason C<< die => $@ >>.	666	will be reported as reason C<< die => $@ >>.
570		667
571	Transport/communication errors are reported as C<< transport_error =>	668	Transport/communication errors are reported as C<< transport_error =>
…		…
590	the package, then the package above the package and so on (e.g.	687	the package, then the package above the package and so on (e.g.
591	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	688	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
592	exists or it runs out of package names.	689	exists or it runs out of package names.
593		690
594	The init function is then called with the newly-created port as context	691	The init function is then called with the newly-created port as context
595	object (C<$SELF>) and the C<@initdata> values as arguments.	692	object (C<$SELF>) and the C<@initdata> values as arguments. It I<must>
		693	call one of the C<rcv> functions to set callbacks on C<$SELF>, otherwise
		694	the port might not get created.
596		695
597	A common idiom is to pass a local port, immediately monitor the spawned	696	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	697	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	698	local port. This two-way monitoring ensures that both ports get cleaned up
600	when there is a problem.	699	when there is a problem.
601		700
		701	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		702	caller before C<spawn> returns (by delaying invocation when spawn is
		703	called for the local node).
		704
602	Example: spawn a chat server port on C<$othernode>.	705	Example: spawn a chat server port on C<$othernode>.
603		706
604	# this node, executed from within a port context:	707	# this node, executed from within a port context:
605	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	708	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
606	mon $server;	709	mon $server;
…		…
620		723
621	sub _spawn {	724	sub _spawn {
622	my $port = shift;	725	my $port = shift;
623	my $init = shift;	726	my $init = shift;
624		727
		728	# rcv will create the actual port
625	local $SELF = "$NODE#$port";	729	local $SELF = "$NODE#$port";
626	eval {	730	eval {
627	&{ load_func $init }	731	&{ load_func $init }
628	};	732	};
629	_self_die if $@;	733	_self_die if $@;
630	}	734	}
631		735
632	sub spawn(@) {	736	sub spawn(@) {
633	my ($noderef, undef) = split /#/, shift, 2;	737	my ($nodeid, undef) = split /#/, shift, 2;
634		738
635	my $id = "$RUNIQ." . $ID++;	739	my $id = "$RUNIQ." . $ID++;
636		740
637	$_[0] =~ /::/	741	$_[0] =~ /::/
638	or Carp::croak "spawn init function must be a fully-qualified name, caught";	742	or Carp::croak "spawn init function must be a fully-qualified name, caught";
639		743
640	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;	744	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
641		745
642	"$noderef#$id"	746	"$nodeid#$id"
643	}	747	}
644		748
645	=item after $timeout, @msg	749	=item after $timeout, @msg
646		750
647	=item after $timeout, $callback	751	=item after $timeout, $callback
…		…
664	? $action[0]()	768	? $action[0]()
665	: snd @action;	769	: snd @action;
666	};	770	};
667	}	771	}
668		772
		773	=item cal $port, @msg, $callback[, $timeout]
		774
		775	A simple form of RPC - sends a message to the given C<$port> with the
		776	given contents (C<@msg>), but adds a reply port to the message.
		777
		778	The reply port is created temporarily just for the purpose of receiving
		779	the reply, and will be C<kil>ed when no longer needed.
		780
		781	A reply message sent to the port is passed to the C<$callback> as-is.
		782
		783	If an optional time-out (in seconds) is given and it is not C<undef>,
		784	then the callback will be called without any arguments after the time-out
		785	elapsed and the port is C<kil>ed.
		786
		787	If no time-out is given (or it is C<undef>), then the local port will
		788	monitor the remote port instead, so it eventually gets cleaned-up.
		789
		790	Currently this function returns the temporary port, but this "feature"
		791	might go in future versions unless you can make a convincing case that
		792	this is indeed useful for something.
		793
		794	=cut
		795
		796	sub cal(@) {
		797	my $timeout = ref $_[-1] ? undef : pop;
		798	my $cb = pop;
		799
		800	my $port = port {
		801	undef $timeout;
		802	kil $SELF;
		803	&$cb;
		804	};
		805
		806	if (defined $timeout) {
		807	$timeout = AE::timer $timeout, 0, sub {
		808	undef $timeout;
		809	kil $port;
		810	$cb->();
		811	};
		812	} else {
		813	mon $_[0], sub {
		814	kil $port;
		815	$cb->();
		816	};
		817	}
		818
		819	push @_, $port;
		820	&snd;
		821
		822	$port
		823	}
		824
669	=back	825	=back
670		826
671	=head1 AnyEvent::MP vs. Distributed Erlang	827	=head1 AnyEvent::MP vs. Distributed Erlang
672		828
673	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	829	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	830	== 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	831	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
676	sample:	832	sample:
677		833
678	http://www.Erlang.se/doc/programming_rules.shtml	834	http://www.erlang.se/doc/programming_rules.shtml
679	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	835	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	836	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	837	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
682		838
683	Despite the similarities, there are also some important differences:	839	Despite the similarities, there are also some important differences:
684		840
685	=over 4	841	=over 4
686		842
687	=item * Node IDs are arbitrary strings in AEMP.	843	=item * Node IDs are arbitrary strings in AEMP.
688		844
689	Erlang relies on special naming and DNS to work everywhere in the same	845	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	846	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.	847	configuration or DNS), and possibly the addresses of some seed nodes, but
		848	will otherwise discover other nodes (and their IDs) itself.
692		849
693	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	850	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
694	uses "local ports are like remote ports".	851	uses "local ports are like remote ports".
695		852
696	The failure modes for local ports are quite different (runtime errors	853	The failure modes for local ports are quite different (runtime errors
…		…
709		866
710	Erlang uses processes that selectively receive messages, and therefore	867	Erlang uses processes that selectively receive messages, and therefore
711	needs a queue. AEMP is event based, queuing messages would serve no	868	needs a queue. AEMP is event based, queuing messages would serve no
712	useful purpose. For the same reason the pattern-matching abilities of	869	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	870	AnyEvent::MP are more limited, as there is little need to be able to
714	filter messages without dequeing them.	871	filter messages without dequeuing them.
715		872
716	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	873	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
717		874
718	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	875	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
719		876
…		…
721	so does not need a queue that can overflow). AEMP sends are immediate,	878	so does not need a queue that can overflow). AEMP sends are immediate,
722	connection establishment is handled in the background.	879	connection establishment is handled in the background.
723		880
724	=item * Erlang suffers from silent message loss, AEMP does not.	881	=item * Erlang suffers from silent message loss, AEMP does not.
725		882
726	Erlang makes few guarantees on messages delivery - messages can get lost	883	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,	884	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).	885	b, and c, and the other side only receives messages a and c).
729		886
730	AEMP guarantees correct ordering, and the guarantee that after one message	887	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	888	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	889	monitoring raises an error, so there are no silent "holes" in the message
733	sequence.	890	sequence.
…		…
795	overhead, as well as having to keep a proxy object everywhere.	952	overhead, as well as having to keep a proxy object everywhere.
796		953
797	Strings can easily be printed, easily serialised etc. and need no special	954	Strings can easily be printed, easily serialised etc. and need no special
798	procedures to be "valid".	955	procedures to be "valid".
799		956
800	And as a result, a miniport consists of a single closure stored in a	957	And as a result, a port with just a default receiver consists of a single
801	global hash - it can't become much cheaper.	958	closure stored in a global hash - it can't become much cheaper.
802		959
803	=item Why favour JSON, why not a real serialising format such as Storable?	960	=item Why favour JSON, why not a real serialising format such as Storable?
804		961
805	In fact, any AnyEvent::MP node will happily accept Storable as framing	962	In fact, any AnyEvent::MP node will happily accept Storable as framing
806	format, but currently there is no way to make a node use Storable by	963	format, but currently there is no way to make a node use Storable by
…		…
822		979
823	L<AnyEvent::MP::Intro> - a gentle introduction.	980	L<AnyEvent::MP::Intro> - a gentle introduction.
824		981
825	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	982	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
826		983
827	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	984	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
828	your applications.	985	your applications.
		986
		987	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
		988
		989	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
		990	all nodes.
829		991
830	L<AnyEvent>.	992	L<AnyEvent>.
831		993
832	=head1 AUTHOR	994	=head1 AUTHOR
833		995

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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 1.114 by root, Thu Apr 22 16:06:19 2010 UTC