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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.75 by root, Mon Aug 31 13:18:06 2009 UTC vs.
Revision 1.108 by root, Wed Dec 30 13:37:53 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 - uptodate, but incomplete.	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
…		…
55	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.
56		66
57	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>
58	manual page and the examples under F<eg/>.	68	manual page and the examples under F<eg/>.
59		69
60	At the moment, this module family is a bit underdocumented.
61
62	=head1 CONCEPTS	70	=head1 CONCEPTS
63		71
64	=over 4	72	=over 4
65		73
66	=item port	74	=item port
67		75
68	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).
69		78
70	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
71	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
72	anything was listening for them or not.	81	anything was listening for them or not.
73		82
…		…
84		93
85	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
86	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
87	currently.	96	currently.
88		97
89	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
90		99
91	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
92	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
93	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
94	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
98	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
99	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
100	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
101	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
102		111
103	=item seeds - C<host:port>	112	=item seed nodes
104		113
105	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
106	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
107	network. This node is called a seed.	116	network. This node is called a seed.
108		117
109	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
110	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
111	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
112	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.
113	join the network.
114		129
115	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
116	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.
117		139
118	=back	140	=back
119		141
120	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
121		143
…		…
133		155
134	use AE ();	156	use AE ();
135		157
136	use base "Exporter";	158	use base "Exporter";
137		159
138	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.24;
139		161
140	our @EXPORT = qw(	162	our @EXPORT = qw(
141	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
142	configure	164	configure
143	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
144	port	166	port
145	);	167	);
146		168
147	our $SELF;	169	our $SELF;
148		170
…		…
160		182
161	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
162		184
163	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.
164		186
		187	=item configure $profile, key => value...
		188
165	=item configure key => value...	189	=item configure key => value...
166		190
167	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
168	"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
169	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
170	some other nodes in the network to discover other nodes.	194	some other nodes in the network to discover other nodes.
171		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
172	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
173	never) before calling other AnyEvent::MP functions.	200	never) before calling other AnyEvent::MP functions.
174		201
175	=over 4	202	=over 4
176		203
177	=item step 1, gathering configuration from profiles	204	=item step 1, gathering configuration from profiles
178		205
179	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
180	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
181	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
182	-n>) will be used as profile name.	209	missing, then the nodename (F<uname -n>) will be used as profile name.
183		210
184	The profile data is then gathered as follows:	211	The profile data is then gathered as follows:
185		212
186	First, all remaining key => value pairs (all of which are conviniently	213	First, all remaining key => value pairs (all of which are conveniently
187	undocumented at the moment) will be interpreted as configuration	214	undocumented at the moment) will be interpreted as configuration
188	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
189	default configuration (see the F<aemp> utility), then the chain of	216	default configuration (see the F<aemp> utility), then the chain of
190	profiles chosen by the profile name (and any C<parent> attributes).	217	profiles chosen by the profile name (and any C<parent> attributes).
191		218
…		…
215	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
216	connectivity with at least one node at any point in time.	243	connectivity with at least one node at any point in time.
217		244
218	=back	245	=back
219		246
220	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.
221	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.
222		249
223	configure	250	configure
224		251
225	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
…		…
359	msg1 => sub { ... },	386	msg1 => sub { ... },
360	...	387	...
361	;	388	;
362		389
363	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
364	(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.
365		392
366	rcv $port, $otherport => sub {	393	rcv $port, $otherport => sub {
367	my @reply = @_;	394	my @reply = @_;
368		395
369	rcv $SELF, $otherport;	396	rcv $SELF, $otherport;
…		…
382	if (ref $_[0]) {	409	if (ref $_[0]) {
383	if (my $self = $PORT_DATA{$portid}) {	410	if (my $self = $PORT_DATA{$portid}) {
384	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
385	or Carp::croak "$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";
386		413
387	$self->[2] = shift;	414	$self->[0] = shift;
388	} else {	415	} else {
389	my $cb = shift;	416	my $cb = shift;
390	$PORT{$portid} = sub {	417	$PORT{$portid} = sub {
391	local $SELF = $port;	418	local $SELF = $port;
392	eval { &$cb }; _self_die if $@;	419	eval { &$cb }; _self_die if $@;
393	};	420	};
394	}	421	}
395	} elsif (defined $_[0]) {	422	} elsif (defined $_[0]) {
396	my $self = $PORT_DATA{$portid} \|\|= do {	423	my $self = $PORT_DATA{$portid} \|\|= do {
397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	424	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
398		425
399	$PORT{$portid} = sub {	426	$PORT{$portid} = sub {
400	local $SELF = $port;	427	local $SELF = $port;
401		428
402	if (my $cb = $self->[1]{$_[0]}) {	429	if (my $cb = $self->[1]{$_[0]}) {
…		…
424	}	451	}
425		452
426	$port	453	$port
427	}	454	}
428		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
429	=item $closure = psub { BLOCK }	493	=item $closure = psub { BLOCK }
430		494
431	Remembers C<$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
432	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>
433	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 $SELF, sub {
		500	BLOCK } } >>.
434		501
435	This is useful when you register callbacks from C<rcv> callbacks:	502	This is useful when you register callbacks from C<rcv> callbacks:
436		503
437	rcv delayed_reply => sub {	504	rcv delayed_reply => sub {
438	my ($delay, @reply) = @_;	505	my ($delay, @reply) = @_;
…		…
474		541
475	Monitor the given port and do something when the port is killed or	542	Monitor the given port and do something when the port is killed or
476	messages to it were lost, and optionally return a guard that can be used	543	messages to it were lost, and optionally return a guard that can be used
477	to stop monitoring again.	544	to stop monitoring again.
478		545
		546	In the first form (callback), the callback is simply called with any
		547	number of C<@reason> elements (no @reason means that the port was deleted
		548	"normally"). Note also that I<< the callback B<must> never die >>, so use
		549	C<eval> if unsure.
		550
		551	In the second form (another port given), the other port (C<$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
479	C<mon> effectively guarantees that, in the absence of hardware failures,	572	C<mon> effectively guarantees that, in the absence of hardware failures,
480	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
481	arrive, or the monitoring action will be invoked after possible message	574	arrive, or the monitoring action will be invoked after possible message
482	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
483	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
484	port). After the monitoring action was invoked, further messages might get	577	port). After the monitoring action was invoked, further messages might get
485	delivered again.	578	delivered again.
486		579
487	Note that monitoring-actions are one-shot: once messages are lost (and a	580	Inter-host-connection timeouts and monitoring depend on the transport
488	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).
489		584
490	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
491	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
492	"normally"). Note also that I<< the callback B<must> never die >>, so use	587	to ensure some maximum latency.
493	C<eval> if unsure.
494
495	In the second form (another port given), the other port (C<$rcvport>)
496	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
497	"normal" kils nothing happens, while under all other conditions, the other
498	port is killed with the same reason.
499
500	The third form (kill self) is the same as the second form, except that
501	C<$rvport> defaults to C<$SELF>.
502
503	In the last form (message), a message of the form C<@msg, @reason> will be
504	C<snd>.
505
506	As a rule of thumb, monitoring requests should always monitor a port from
507	a local port (or callback). The reason is that kill messages might get
508	lost, just like any other message. Another less obvious reason is that
509	even monitoring requests can get lost (for exmaple, when the connection
510	to the other node goes down permanently). When monitoring a port locally
511	these problems do not exist.
512		588
513	Example: call a given callback when C<$port> is killed.	589	Example: call a given callback when C<$port> is killed.
514		590
515	mon $port, sub { warn "port died because of <@_>\n" };	591	mon $port, sub { warn "port died because of <@_>\n" };
516		592
…		…
544	}	620	}
545		621
546	$node->monitor ($port, $cb);	622	$node->monitor ($port, $cb);
547		623
548	defined wantarray	624	defined wantarray
549	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	625	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
550	}	626	}
551		627
552	=item $guard = mon_guard $port, $ref, $ref...	628	=item $guard = mon_guard $port, $ref, $ref...
553		629
554	Monitors the given C<$port> and keeps the passed references. When the port	630	Monitors the given C<$port> and keeps the passed references. When the port
…		…
577		653
578	=item kil $port[, @reason]	654	=item kil $port[, @reason]
579		655
580	Kill the specified port with the given C<@reason>.	656	Kill the specified port with the given C<@reason>.
581		657
582	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" -
583	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
584	"normally").	660	(C<mon $mport, $lport> form) to get killed.
585		661
586	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>
587	C<mon>, see above).	663	form) get killed with the same reason.
588		664
589	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
590	will be reported as reason C<< die => $@ >>.	666	will be reported as reason C<< die => $@ >>.
591		667
592	Transport/communication errors are reported as C<< transport_error =>	668	Transport/communication errors are reported as C<< transport_error =>
…		…
611	the package, then the package above the package and so on (e.g.	687	the package, then the package above the package and so on (e.g.
612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	688	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
613	exists or it runs out of package names.	689	exists or it runs out of package names.
614		690
615	The init function is then called with the newly-created port as context	691	The init function is then called with the newly-created port as context
616	object (C<$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.
617		695
618	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
619	port, and in the remote init function, immediately monitor the passed	697	port, and in the remote init function, immediately monitor the passed
620	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
621	when there is a problem.	699	when there is a problem.
622		700
		701	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		702	caller before C<spawn> returns (by delaying invocation when spawn is
		703	called for the local node).
		704
623	Example: spawn a chat server port on C<$othernode>.	705	Example: spawn a chat server port on C<$othernode>.
624		706
625	# this node, executed from within a port context:	707	# this node, executed from within a port context:
626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	708	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
627	mon $server;	709	mon $server;
…		…
641		723
642	sub _spawn {	724	sub _spawn {
643	my $port = shift;	725	my $port = shift;
644	my $init = shift;	726	my $init = shift;
645		727
		728	# rcv will create the actual port
646	local $SELF = "$NODE#$port";	729	local $SELF = "$NODE#$port";
647	eval {	730	eval {
648	&{ load_func $init }	731	&{ load_func $init }
649	};	732	};
650	_self_die if $@;	733	_self_die if $@;
…		…
685	? $action[0]()	768	? $action[0]()
686	: snd @action;	769	: snd @action;
687	};	770	};
688	}	771	}
689		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
690	=back	825	=back
691		826
692	=head1 AnyEvent::MP vs. Distributed Erlang	827	=head1 AnyEvent::MP vs. Distributed Erlang
693		828
694	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
695	== 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
696	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
697	sample:	832	sample:
698		833
699	http://www.Erlang.se/doc/programming_rules.shtml	834	http://www.erlang.se/doc/programming_rules.shtml
700	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
701	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
702	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
703		838
704	Despite the similarities, there are also some important differences:	839	Despite the similarities, there are also some important differences:
705		840
706	=over 4	841	=over 4
707		842
708	=item * Node IDs are arbitrary strings in AEMP.	843	=item * Node IDs are arbitrary strings in AEMP.
709		844
710	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
711	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
712	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.
713		849
714	=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
715	uses "local ports are like remote ports".	851	uses "local ports are like remote ports".
716		852
717	The failure modes for local ports are quite different (runtime errors	853	The failure modes for local ports are quite different (runtime errors
…		…
730		866
731	Erlang uses processes that selectively receive messages, and therefore	867	Erlang uses processes that selectively receive messages, and therefore
732	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
733	useful purpose. For the same reason the pattern-matching abilities of	869	useful purpose. For the same reason the pattern-matching abilities of
734	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
735	filter messages without dequeing them.	871	filter messages without dequeuing them.
736		872
737	(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).
738		874
739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	875	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
740		876
…		…
742	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,
743	connection establishment is handled in the background.	879	connection establishment is handled in the background.
744		880
745	=item * Erlang suffers from silent message loss, AEMP does not.	881	=item * Erlang suffers from silent message loss, AEMP does not.
746		882
747	Erlang makes few guarantees on messages delivery - messages can get lost	883	Erlang implements few guarantees on messages delivery - messages can get
748	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,
749	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).
750		886
751	AEMP guarantees correct ordering, and the guarantee that after one message	887	AEMP guarantees correct ordering, and the guarantee that after one message
752	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
753	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
754	sequence.	890	sequence.
…		…
846	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	982	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
847		983
848	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	984	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
849	your applications.	985	your applications.
850		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
851	L<AnyEvent>.	992	L<AnyEvent>.
852		993
853	=head1 AUTHOR	994	=head1 AUTHOR
854		995
855	Marc Lehmann <schmorp@schmorp.de>	996	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.75 by root, Mon Aug 31 13:18:06 2009 UTC vs. Revision 1.108 by root, Wed Dec 30 13:37:53 2009 UTC

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Revision 1.75 by root, Mon Aug 31 13:18:06 2009 UTC vs.
Revision 1.108 by root, Wed Dec 30 13:37:53 2009 UTC