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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.76 by root, Mon Aug 31 18:45:05 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
30	rcv $port, pong => sub { warn "pong received\n" };	30	rcv $port, pong => sub { warn "pong received\n" };
31		31
32	# create a port on another node	32	# create a port on another node
33	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
34		34
		35	# destroy a prot again
		36	kil $port; # "normal" kill
		37	kil $port, my_error => "everything is broken"; # error kill
		38
35	# monitoring	39	# monitoring
36	mon $port, $cb->(@msg) # callback is invoked on death	40	mon $localport, $cb->(@msg) # callback is invoked on death
37	mon $port, $otherport # kill otherport on abnormal death	41	mon $localport, $otherport # kill otherport on abnormal death
38	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	};
39		51
40	=head1 CURRENT STATUS	52	=head1 CURRENT STATUS
41		53
42	bin/aemp - stable.	54	bin/aemp - stable.
43	AnyEvent::MP - stable API, should work.	55	AnyEvent::MP - stable API, should work.
44	AnyEvent::MP::Intro - epxlains most concepts.	56	AnyEvent::MP::Intro - explains most concepts.
45	AnyEvent::MP::Kernel - mostly stable.	57	AnyEvent::MP::Kernel - mostly stable API.
46	AnyEvent::MP::Global - stable API, protocol not yet final.	58	AnyEvent::MP::Global - stable API.
47
48	stay tuned.
49		59
50	=head1 DESCRIPTION	60	=head1 DESCRIPTION
51		61
52	This module (-family) implements a simple message passing framework.	62	This module (-family) implements a simple message passing framework.
53		63
…		…
61		71
62	=over 4	72	=over 4
63		73
64	=item port	74	=item port
65		75
66	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).
67		78
68	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
69	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
70	anything was listening for them or not.	81	anything was listening for them or not.
71		82
…		…
82		93
83	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
84	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
85	currently.	96	currently.
86		97
87	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
88		99
89	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
90	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
91	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
92	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
96	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
97	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
98	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
99	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
100		111
101	=item seeds - C<host:port>	112	=item seed nodes
102		113
103	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
104	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
105	network. This node is called a seed.	116	network. This node is called a seed.
106		117
107	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
108	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
109	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
110	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.
111	join the network.
112		129
113	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
114	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.
115		139
116	=back	140	=back
117		141
118	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
119		143
…		…
131		155
132	use AE ();	156	use AE ();
133		157
134	use base "Exporter";	158	use base "Exporter";
135		159
136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.24;
137		161
138	our @EXPORT = qw(	162	our @EXPORT = qw(
139	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
140	configure	164	configure
141	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
142	port	166	port
143	);	167	);
144		168
145	our $SELF;	169	our $SELF;
146		170
…		…
158		182
159	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
160		184
161	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.
162		186
		187	=item configure $profile, key => value...
		188
163	=item configure key => value...	189	=item configure key => value...
164		190
165	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
166	"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
167	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
…		…
174		200
175	=item step 1, gathering configuration from profiles	201	=item step 1, gathering configuration from profiles
176		202
177	The function first looks up a profile in the aemp configuration (see the	203	The function first looks up a profile in the aemp configuration (see the
178	L<aemp> commandline utility). The profile name can be specified via the	204	L<aemp> commandline utility). The profile name can be specified via the
179	named C<profile> parameter. If it is missing, then the nodename (F<uname	205	named C<profile> parameter or can simply be the first parameter). If it is
180	-n>) will be used as profile name.	206	missing, then the nodename (F<uname -n>) will be used as profile name.
181		207
182	The profile data is then gathered as follows:	208	The profile data is then gathered as follows:
183		209
184	First, all remaining key => value pairs (all of which are conviniently	210	First, all remaining key => value pairs (all of which are conveniently
185	undocumented at the moment) will be interpreted as configuration	211	undocumented at the moment) will be interpreted as configuration
186	data. Then they will be overwritten by any values specified in the global	212	data. Then they will be overwritten by any values specified in the global
187	default configuration (see the F<aemp> utility), then the chain of	213	default configuration (see the F<aemp> utility), then the chain of
188	profiles chosen by the profile name (and any C<parent> attributes).	214	profiles chosen by the profile name (and any C<parent> attributes).
189		215
…		…
213	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
214	connectivity with at least one node at any point in time.	240	connectivity with at least one node at any point in time.
215		241
216	=back	242	=back
217		243
218	Example: become a distributed node using the locla node name as profile.	244	Example: become a distributed node using the local node name as profile.
219	This should be the most common form of invocation for "daemon"-type nodes.	245	This should be the most common form of invocation for "daemon"-type nodes.
220		246
221	configure	247	configure
222		248
223	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
…		…
357	msg1 => sub { ... },	383	msg1 => sub { ... },
358	...	384	...
359	;	385	;
360		386
361	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
362	(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.
363		389
364	rcv $port, $otherport => sub {	390	rcv $port, $otherport => sub {
365	my @reply = @_;	391	my @reply = @_;
366		392
367	rcv $SELF, $otherport;	393	rcv $SELF, $otherport;
…		…
380	if (ref $_[0]) {	406	if (ref $_[0]) {
381	if (my $self = $PORT_DATA{$portid}) {	407	if (my $self = $PORT_DATA{$portid}) {
382	"AnyEvent::MP::Port" eq ref $self	408	"AnyEvent::MP::Port" eq ref $self
383	or Carp::croak "$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";
384		410
385	$self->[2] = shift;	411	$self->[0] = shift;
386	} else {	412	} else {
387	my $cb = shift;	413	my $cb = shift;
388	$PORT{$portid} = sub {	414	$PORT{$portid} = sub {
389	local $SELF = $port;	415	local $SELF = $port;
390	eval { &$cb }; _self_die if $@;	416	eval { &$cb }; _self_die if $@;
391	};	417	};
392	}	418	}
393	} elsif (defined $_[0]) {	419	} elsif (defined $_[0]) {
394	my $self = $PORT_DATA{$portid} \|\|= do {	420	my $self = $PORT_DATA{$portid} \|\|= do {
395	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	421	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
396		422
397	$PORT{$portid} = sub {	423	$PORT{$portid} = sub {
398	local $SELF = $port;	424	local $SELF = $port;
399		425
400	if (my $cb = $self->[1]{$_[0]}) {	426	if (my $cb = $self->[1]{$_[0]}) {
…		…
422	}	448	}
423		449
424	$port	450	$port
425	}	451	}
426		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
427	=item $closure = psub { BLOCK }	490	=item $closure = psub { BLOCK }
428		491
429	Remembers C<$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
430	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>
431	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 $SELF, sub {
		497	BLOCK } } >>.
432		498
433	This is useful when you register callbacks from C<rcv> callbacks:	499	This is useful when you register callbacks from C<rcv> callbacks:
434		500
435	rcv delayed_reply => sub {	501	rcv delayed_reply => sub {
436	my ($delay, @reply) = @_;	502	my ($delay, @reply) = @_;
…		…
472		538
473	Monitor the given port and do something when the port is killed or	539	Monitor the given port and do something when the port is killed or
474	messages to it were lost, and optionally return a guard that can be used	540	messages to it were lost, and optionally return a guard that can be used
475	to stop monitoring again.	541	to stop monitoring again.
476		542
		543	In the first form (callback), the callback is simply called with any
		544	number of C<@reason> elements (no @reason means that the port was deleted
		545	"normally"). Note also that I<< the callback B<must> never die >>, so use
		546	C<eval> if unsure.
		547
		548	In the second form (another port given), the other port (C<$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
477	C<mon> effectively guarantees that, in the absence of hardware failures,	569	C<mon> effectively guarantees that, in the absence of hardware failures,
478	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
479	arrive, or the monitoring action will be invoked after possible message	571	arrive, or the monitoring action will be invoked after possible message
480	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
481	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
482	port). After the monitoring action was invoked, further messages might get	574	port). After the monitoring action was invoked, further messages might get
483	delivered again.	575	delivered again.
484		576
485	Note that monitoring-actions are one-shot: once messages are lost (and a	577	Inter-host-connection timeouts and monitoring depend on the transport
486	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).
487		581
488	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
489	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
490	"normally"). Note also that I<< the callback B<must> never die >>, so use	584	to ensure some maximum latency.
491	C<eval> if unsure.
492
493	In the second form (another port given), the other port (C<$rcvport>)
494	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
495	"normal" kils nothing happens, while under all other conditions, the other
496	port is killed with the same reason.
497
498	The third form (kill self) is the same as the second form, except that
499	C<$rvport> defaults to C<$SELF>.
500
501	In the last form (message), a message of the form C<@msg, @reason> will be
502	C<snd>.
503
504	As a rule of thumb, monitoring requests should always monitor a port from
505	a local port (or callback). The reason is that kill messages might get
506	lost, just like any other message. Another less obvious reason is that
507	even monitoring requests can get lost (for exmaple, when the connection
508	to the other node goes down permanently). When monitoring a port locally
509	these problems do not exist.
510		585
511	Example: call a given callback when C<$port> is killed.	586	Example: call a given callback when C<$port> is killed.
512		587
513	mon $port, sub { warn "port died because of <@_>\n" };	588	mon $port, sub { warn "port died because of <@_>\n" };
514		589
…		…
542	}	617	}
543		618
544	$node->monitor ($port, $cb);	619	$node->monitor ($port, $cb);
545		620
546	defined wantarray	621	defined wantarray
547	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	622	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
548	}	623	}
549		624
550	=item $guard = mon_guard $port, $ref, $ref...	625	=item $guard = mon_guard $port, $ref, $ref...
551		626
552	Monitors the given C<$port> and keeps the passed references. When the port	627	Monitors the given C<$port> and keeps the passed references. When the port
…		…
609	the package, then the package above the package and so on (e.g.	684	the package, then the package above the package and so on (e.g.
610	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	685	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
611	exists or it runs out of package names.	686	exists or it runs out of package names.
612		687
613	The init function is then called with the newly-created port as context	688	The init function is then called with the newly-created port as context
614	object (C<$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.
615		692
616	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
617	port, and in the remote init function, immediately monitor the passed	694	port, and in the remote init function, immediately monitor the passed
618	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
619	when there is a problem.	696	when there is a problem.
620		697
		698	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		699	caller before C<spawn> returns (by delaying invocation when spawn is
		700	called for the local node).
		701
621	Example: spawn a chat server port on C<$othernode>.	702	Example: spawn a chat server port on C<$othernode>.
622		703
623	# this node, executed from within a port context:	704	# this node, executed from within a port context:
624	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	705	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
625	mon $server;	706	mon $server;
…		…
639		720
640	sub _spawn {	721	sub _spawn {
641	my $port = shift;	722	my $port = shift;
642	my $init = shift;	723	my $init = shift;
643		724
		725	# rcv will create the actual port
644	local $SELF = "$NODE#$port";	726	local $SELF = "$NODE#$port";
645	eval {	727	eval {
646	&{ load_func $init }	728	&{ load_func $init }
647	};	729	};
648	_self_die if $@;	730	_self_die if $@;
…		…
683	? $action[0]()	765	? $action[0]()
684	: snd @action;	766	: snd @action;
685	};	767	};
686	}	768	}
687		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
688	=back	822	=back
689		823
690	=head1 AnyEvent::MP vs. Distributed Erlang	824	=head1 AnyEvent::MP vs. Distributed Erlang
691		825
692	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
693	== 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
694	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
695	sample:	829	sample:
696		830
697	http://www.Erlang.se/doc/programming_rules.shtml	831	http://www.erlang.se/doc/programming_rules.shtml
698	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
699	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
700	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
701		835
702	Despite the similarities, there are also some important differences:	836	Despite the similarities, there are also some important differences:
703		837
704	=over 4	838	=over 4
705		839
706	=item * Node IDs are arbitrary strings in AEMP.	840	=item * Node IDs are arbitrary strings in AEMP.
707		841
708	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
709	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
710	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.
711		846
712	=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
713	uses "local ports are like remote ports".	848	uses "local ports are like remote ports".
714		849
715	The failure modes for local ports are quite different (runtime errors	850	The failure modes for local ports are quite different (runtime errors
…		…
728		863
729	Erlang uses processes that selectively receive messages, and therefore	864	Erlang uses processes that selectively receive messages, and therefore
730	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
731	useful purpose. For the same reason the pattern-matching abilities of	866	useful purpose. For the same reason the pattern-matching abilities of
732	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
733	filter messages without dequeing them.	868	filter messages without dequeuing them.
734		869
735	(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).
736		871
737	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	872	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
738		873
…		…
740	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,
741	connection establishment is handled in the background.	876	connection establishment is handled in the background.
742		877
743	=item * Erlang suffers from silent message loss, AEMP does not.	878	=item * Erlang suffers from silent message loss, AEMP does not.
744		879
745	Erlang makes few guarantees on messages delivery - messages can get lost	880	Erlang implements few guarantees on messages delivery - messages can get
746	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,
747	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).
748		883
749	AEMP guarantees correct ordering, and the guarantee that after one message	884	AEMP guarantees correct ordering, and the guarantee that after one message
750	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
751	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
752	sequence.	887	sequence.
…		…
844	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	979	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
845		980
846	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	981	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
847	your applications.	982	your applications.
848		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
849	L<AnyEvent>.	989	L<AnyEvent>.
850		990
851	=head1 AUTHOR	991	=head1 AUTHOR
852		992
853	Marc Lehmann <schmorp@schmorp.de>	993	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC vs. Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC vs.
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC