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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.73 by root, Mon Aug 31 11:08:25 2009 UTC vs.
Revision 1.110 by root, Sun Mar 7 19:29:07 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	configure;	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;
31	rcv $port, pong => sub { warn "pong received\n" };	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
43	bin/aemp - stable.	54	bin/aemp - stable.
44	AnyEvent::MP - stable API, should work.	55	AnyEvent::MP - stable API, should work.
45	AnyEvent::MP::Intro - uptodate, but incomplete.	56	AnyEvent::MP::Intro - explains most concepts.
46	AnyEvent::MP::Kernel - mostly stable.	57	AnyEvent::MP::Kernel - mostly stable API.
47	AnyEvent::MP::Global - stable API, protocol not yet final.	58	AnyEvent::MP::Global - stable API.
48
49	stay tuned.
50		59
51	=head1 DESCRIPTION	60	=head1 DESCRIPTION
52		61
53	This module (-family) implements a simple message passing framework.	62	This module (-family) implements a simple message passing framework.
54		63
…		…
56	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.
57		66
58	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>
59	manual page and the examples under F<eg/>.	68	manual page and the examples under F<eg/>.
60		69
61	At the moment, this module family is a bit underdocumented.
62
63	=head1 CONCEPTS	70	=head1 CONCEPTS
64		71
65	=over 4	72	=over 4
66		73
67	=item port	74	=item port
68		75
69	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).
70		78
71	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
72	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
73	anything was listening for them or not.	81	anything was listening for them or not.
74		82
…		…
85		93
86	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
87	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
88	currently.	96	currently.
89		97
90	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
91		99
92	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
93	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
94	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
95	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
99	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
100	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
101	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
102	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
103		111
104	=item seeds - C<host:port>	112	=item seed nodes
105		113
106	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
107	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
108	network. This node is called a seed.	116	network. This node is called a seed.
109		117
110	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
111	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
112	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
113	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.
114	join the network.
115		129
116	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
117	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.
118		139
119	=back	140	=back
120		141
121	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
122		143
…		…
134		155
135	use AE ();	156	use AE ();
136		157
137	use base "Exporter";	158	use base "Exporter";
138		159
139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.26;
140		161
141	our @EXPORT = qw(	162	our @EXPORT = qw(
142	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
143	configure	164	configure
144	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
145	port	166	port
146	);	167	);
147		168
148	our $SELF;	169	our $SELF;
149		170
…		…
161		182
162	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
163		184
164	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.
165		186
		187	=item configure $profile, key => value...
		188
166	=item configure key => value...	189	=item configure key => value...
167		190
168	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
169	"distributed mode") it has to configure itself - the minimum a node needs	192	"distributed mode") it has to configure itself - the minimum a node needs
170	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
171	some other nodes in the network to discover other nodes.	194	some other nodes in the network to discover other nodes.
172		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
173	This function configures a node - it must be called exactly once (or	199	This function configures a node - it must be called exactly once (or
174	never) before calling other AnyEvent::MP functions.	200	never) before calling other AnyEvent::MP functions.
175		201
176	=over 4	202	=over 4
177		203
178	=item step 1, gathering configuration from profiles	204	=item step 1, gathering configuration from profiles
179		205
180	The function first looks up a 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 name can be specified via the	207	L<aemp> commandline utility). The profile name can be specified via the
182	named C<profile> parameter. If it is missing, then the nodename (F<uname	208	named C<profile> parameter or can simply be the first parameter). If it is
183	-n>) will be used as profile name.	209	missing, then the nodename (F<uname -n>) will be used as profile name.
184		210
185	The profile data is then gathered as follows:	211	The profile data is then gathered as follows:
186		212
187	First, all remaining key => value pairs (all of which are conviniently	213	First, all remaining key => value pairs (all of which are conveniently
188	undocumented at the moment) will be interpreted as configuration	214	undocumented at the moment) will be interpreted as configuration
189	data. Then they will be overwritten by any values specified in the global	215	data. Then they will be overwritten by any values specified in the global
190	default configuration (see the F<aemp> utility), then the chain of	216	default configuration (see the F<aemp> utility), then the chain of
191	profiles chosen by the profile name (and any C<parent> attributes).	217	profiles chosen by the profile name (and any C<parent> attributes).
192		218
…		…
216	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
217	connectivity with at least one node at any point in time.	243	connectivity with at least one node at any point in time.
218		244
219	=back	245	=back
220		246
221	Example: become a distributed node using the locla node name as profile.	247	Example: become a distributed node using the local node name as profile.
222	This should be the most common form of invocation for "daemon"-type nodes.	248	This should be the most common form of invocation for "daemon"-type nodes.
223		249
224	configure	250	configure
225		251
226	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
…		…
231	Example: configure a node using a profile called seed, which si suitable	257	Example: configure a node using a profile called seed, which si suitable
232	for a seed node as it binds on all local addresses on a fixed port (4040,	258	for a seed node as it binds on all local addresses on a fixed port (4040,
233	customary for aemp).	259	customary for aemp).
234		260
235	# use the aemp commandline utility	261	# use the aemp commandline utility
236	# aemp profile seed setnodeid anon/ setbinds '*:4040'	262	# aemp profile seed nodeid anon/ binds '*:4040'
237		263
238	# then use it	264	# then use it
239	configure profile => "seed";	265	configure profile => "seed";
240		266
241	# or simply use aemp from the shell again:	267	# or simply use aemp from the shell again:
…		…
360	msg1 => sub { ... },	386	msg1 => sub { ... },
361	...	387	...
362	;	388	;
363		389
364	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
365	(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.
366		392
367	rcv $port, $otherport => sub {	393	rcv $port, $otherport => sub {
368	my @reply = @_;	394	my @reply = @_;
369		395
370	rcv $SELF, $otherport;	396	rcv $SELF, $otherport;
…		…
372		398
373	=cut	399	=cut
374		400
375	sub rcv($@) {	401	sub rcv($@) {
376	my $port = shift;	402	my $port = shift;
377	my ($noderef, $portid) = split /#/, $port, 2;	403	my ($nodeid, $portid) = split /#/, $port, 2;
378		404
379	$NODE{$noderef} == $NODE{""}	405	$NODE{$nodeid} == $NODE{""}
380	or Carp::croak "$port: rcv can only be called on local ports, caught";	406	or Carp::croak "$port: rcv can only be called on local ports, caught";
381		407
382	while (@_) {	408	while (@_) {
383	if (ref $_[0]) {	409	if (ref $_[0]) {
384	if (my $self = $PORT_DATA{$portid}) {	410	if (my $self = $PORT_DATA{$portid}) {
385	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
386	or Carp::croak "$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";
387		413
388	$self->[2] = shift;	414	$self->[0] = shift;
389	} else {	415	} else {
390	my $cb = shift;	416	my $cb = shift;
391	$PORT{$portid} = sub {	417	$PORT{$portid} = sub {
392	local $SELF = $port;	418	local $SELF = $port;
393	eval { &$cb }; _self_die if $@;	419	eval { &$cb }; _self_die if $@;
394	};	420	};
395	}	421	}
396	} elsif (defined $_[0]) {	422	} elsif (defined $_[0]) {
397	my $self = $PORT_DATA{$portid} \|\|= do {	423	my $self = $PORT_DATA{$portid} \|\|= do {
398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	424	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
399		425
400	$PORT{$portid} = sub {	426	$PORT{$portid} = sub {
401	local $SELF = $port;	427	local $SELF = $port;
402		428
403	if (my $cb = $self->[1]{$_[0]}) {	429	if (my $cb = $self->[1]{$_[0]}) {
…		…
425	}	451	}
426		452
427	$port	453	$port
428	}	454	}
429		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
430	=item $closure = psub { BLOCK }	493	=item $closure = psub { BLOCK }
431		494
432	Remembers C<$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
433	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>
434	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 $SELF, sub {
		500	BLOCK } } >>.
435		501
436	This is useful when you register callbacks from C<rcv> callbacks:	502	This is useful when you register callbacks from C<rcv> callbacks:
437		503
438	rcv delayed_reply => sub {	504	rcv delayed_reply => sub {
439	my ($delay, @reply) = @_;	505	my ($delay, @reply) = @_;
…		…
475		541
476	Monitor the given port and do something when the port is killed or	542	Monitor the given port and do something when the port is killed or
477	messages to it were lost, and optionally return a guard that can be used	543	messages to it were lost, and optionally return a guard that can be used
478	to stop monitoring again.	544	to stop monitoring again.
479		545
		546	In the first form (callback), the callback is simply called with any
		547	number of C<@reason> elements (no @reason means that the port was deleted
		548	"normally"). Note also that I<< the callback B<must> never die >>, so use
		549	C<eval> if unsure.
		550
		551	In the second form (another port given), the other port (C<$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
480	C<mon> effectively guarantees that, in the absence of hardware failures,	572	C<mon> effectively guarantees that, in the absence of hardware failures,
481	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
482	arrive, or the monitoring action will be invoked after possible message	574	arrive, or the monitoring action will be invoked after possible message
483	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
484	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
485	port). After the monitoring action was invoked, further messages might get	577	port). After the monitoring action was invoked, further messages might get
486	delivered again.	578	delivered again.
487		579
488	Note that monitoring-actions are one-shot: once messages are lost (and a	580	Inter-host-connection timeouts and monitoring depend on the transport
489	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).
490		584
491	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
492	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
493	"normally"). Note also that I<< the callback B<must> never die >>, so use	587	to ensure some maximum latency.
494	C<eval> if unsure.
495
496	In the second form (another port given), the other port (C<$rcvport>)
497	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
498	"normal" kils nothing happens, while under all other conditions, the other
499	port is killed with the same reason.
500
501	The third form (kill self) is the same as the second form, except that
502	C<$rvport> defaults to C<$SELF>.
503
504	In the last form (message), a message of the form C<@msg, @reason> will be
505	C<snd>.
506
507	As a rule of thumb, monitoring requests should always monitor a port from
508	a local port (or callback). The reason is that kill messages might get
509	lost, just like any other message. Another less obvious reason is that
510	even monitoring requests can get lost (for exmaple, when the connection
511	to the other node goes down permanently). When monitoring a port locally
512	these problems do not exist.
513		588
514	Example: call a given callback when C<$port> is killed.	589	Example: call a given callback when C<$port> is killed.
515		590
516	mon $port, sub { warn "port died because of <@_>\n" };	591	mon $port, sub { warn "port died because of <@_>\n" };
517		592
…		…
524	mon $port, $self => "restart";	599	mon $port, $self => "restart";
525		600
526	=cut	601	=cut
527		602
528	sub mon {	603	sub mon {
529	my ($noderef, $port) = split /#/, shift, 2;	604	my ($nodeid, $port) = split /#/, shift, 2;
530		605
531	my $node = $NODE{$noderef} \|\| add_node $noderef;	606	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
532		607
533	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,';
534		609
535	unless (ref $cb) {	610	unless (ref $cb) {
536	if (@_) {	611	if (@_) {
…		…
545	}	620	}
546		621
547	$node->monitor ($port, $cb);	622	$node->monitor ($port, $cb);
548		623
549	defined wantarray	624	defined wantarray
550	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	625	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
551	}	626	}
552		627
553	=item $guard = mon_guard $port, $ref, $ref...	628	=item $guard = mon_guard $port, $ref, $ref...
554		629
555	Monitors the given C<$port> and keeps the passed references. When the port	630	Monitors the given C<$port> and keeps the passed references. When the port
…		…
578		653
579	=item kil $port[, @reason]	654	=item kil $port[, @reason]
580		655
581	Kill the specified port with the given C<@reason>.	656	Kill the specified port with the given C<@reason>.
582		657
583	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" -
584	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
585	"normally").	660	(C<mon $mport, $lport> form) to get killed.
586		661
587	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>
588	C<mon>, see above).	663	form) get killed with the same reason.
589		664
590	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
591	will be reported as reason C<< die => $@ >>.	666	will be reported as reason C<< die => $@ >>.
592		667
593	Transport/communication errors are reported as C<< transport_error =>	668	Transport/communication errors are reported as C<< transport_error =>
…		…
612	the package, then the package above the package and so on (e.g.	687	the package, then the package above the package and so on (e.g.
613	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	688	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
614	exists or it runs out of package names.	689	exists or it runs out of package names.
615		690
616	The init function is then called with the newly-created port as context	691	The init function is then called with the newly-created port as context
617	object (C<$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.
618		695
619	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
620	port, and in the remote init function, immediately monitor the passed	697	port, and in the remote init function, immediately monitor the passed
621	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
622	when there is a problem.	699	when there is a problem.
623		700
		701	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		702	caller before C<spawn> returns (by delaying invocation when spawn is
		703	called for the local node).
		704
624	Example: spawn a chat server port on C<$othernode>.	705	Example: spawn a chat server port on C<$othernode>.
625		706
626	# this node, executed from within a port context:	707	# this node, executed from within a port context:
627	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	708	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
628	mon $server;	709	mon $server;
…		…
642		723
643	sub _spawn {	724	sub _spawn {
644	my $port = shift;	725	my $port = shift;
645	my $init = shift;	726	my $init = shift;
646		727
		728	# rcv will create the actual port
647	local $SELF = "$NODE#$port";	729	local $SELF = "$NODE#$port";
648	eval {	730	eval {
649	&{ load_func $init }	731	&{ load_func $init }
650	};	732	};
651	_self_die if $@;	733	_self_die if $@;
652	}	734	}
653		735
654	sub spawn(@) {	736	sub spawn(@) {
655	my ($noderef, undef) = split /#/, shift, 2;	737	my ($nodeid, undef) = split /#/, shift, 2;
656		738
657	my $id = "$RUNIQ." . $ID++;	739	my $id = "$RUNIQ." . $ID++;
658		740
659	$_[0] =~ /::/	741	$_[0] =~ /::/
660	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";
661		743
662	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;	744	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
663		745
664	"$noderef#$id"	746	"$nodeid#$id"
665	}	747	}
666		748
667	=item after $timeout, @msg	749	=item after $timeout, @msg
668		750
669	=item after $timeout, $callback	751	=item after $timeout, $callback
…		…
686	? $action[0]()	768	? $action[0]()
687	: snd @action;	769	: snd @action;
688	};	770	};
689	}	771	}
690		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
691	=back	825	=back
692		826
693	=head1 AnyEvent::MP vs. Distributed Erlang	827	=head1 AnyEvent::MP vs. Distributed Erlang
694		828
695	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
696	== 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
697	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
698	sample:	832	sample:
699		833
700	http://www.Erlang.se/doc/programming_rules.shtml	834	http://www.erlang.se/doc/programming_rules.shtml
701	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
702	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
703	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
704		838
705	Despite the similarities, there are also some important differences:	839	Despite the similarities, there are also some important differences:
706		840
707	=over 4	841	=over 4
708		842
709	=item * Node IDs are arbitrary strings in AEMP.	843	=item * Node IDs are arbitrary strings in AEMP.
710		844
711	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
712	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
713	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.
714		849
715	=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
716	uses "local ports are like remote ports".	851	uses "local ports are like remote ports".
717		852
718	The failure modes for local ports are quite different (runtime errors	853	The failure modes for local ports are quite different (runtime errors
…		…
731		866
732	Erlang uses processes that selectively receive messages, and therefore	867	Erlang uses processes that selectively receive messages, and therefore
733	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
734	useful purpose. For the same reason the pattern-matching abilities of	869	useful purpose. For the same reason the pattern-matching abilities of
735	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
736	filter messages without dequeing them.	871	filter messages without dequeuing them.
737		872
738	(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).
739		874
740	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	875	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
741		876
…		…
743	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,
744	connection establishment is handled in the background.	879	connection establishment is handled in the background.
745		880
746	=item * Erlang suffers from silent message loss, AEMP does not.	881	=item * Erlang suffers from silent message loss, AEMP does not.
747		882
748	Erlang makes few guarantees on messages delivery - messages can get lost	883	Erlang implements few guarantees on messages delivery - messages can get
749	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,
750	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).
751		886
752	AEMP guarantees correct ordering, and the guarantee that after one message	887	AEMP guarantees correct ordering, and the guarantee that after one message
753	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
754	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
755	sequence.	890	sequence.
…		…
817	overhead, as well as having to keep a proxy object everywhere.	952	overhead, as well as having to keep a proxy object everywhere.
818		953
819	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
820	procedures to be "valid".	955	procedures to be "valid".
821		956
822	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
823	global hash - it can't become much cheaper.	958	closure stored in a global hash - it can't become much cheaper.
824		959
825	=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?
826		961
827	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
828	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
…		…
847	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	982	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
848		983
849	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	984	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
850	your applications.	985	your applications.
851		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.
		991
852	L<AnyEvent>.	992	L<AnyEvent>.
853		993
854	=head1 AUTHOR	994	=head1 AUTHOR
855		995
856	Marc Lehmann <schmorp@schmorp.de>	996	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.73 by root, Mon Aug 31 11:08:25 2009 UTC vs. Revision 1.110 by root, Sun Mar 7 19:29:07 2010 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.73 by root, Mon Aug 31 11:08:25 2009 UTC vs.
Revision 1.110 by root, Sun Mar 7 19:29:07 2010 UTC