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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.89 by root, Fri Sep 11 16:47:14 2009 UTC vs.
Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC

…		…
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 port 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.
…		…
66		78
67	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
68	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
69	anything was listening for them or not.	81	anything was listening for them or not.
70		82
		83	Ports are represented by (printable) strings called "port IDs".
		84
71	=item port ID - C<nodeid#portname>	85	=item port ID - C<nodeid#portname>
72		86
73	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as	87	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
74	separator, and a port name (a printable string of unspecified format).	88	separator, and a port name (a printable string of unspecified format).
75		89
…		…
79	which enables nodes to manage each other remotely, and to create new	93	which enables nodes to manage each other remotely, and to create new
80	ports.	94	ports.
81		95
82	Nodes are either public (have one or more listening ports) or private	96	Nodes are either public (have one or more listening ports) or private
83	(no listening ports). Private nodes cannot talk to other private nodes	97	(no listening ports). Private nodes cannot talk to other private nodes
84	currently.	98	currently, but all nodes can talk to public nodes.
85		99
		100	Nodes is represented by (printable) strings called "node IDs".
		101
86	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>	102	=item node ID - C<[A-Za-z0-9_\-.:]*>
87		103
88	A node ID is a string that uniquely identifies the node within a	104	A node ID is a string that uniquely identifies the node within a
89	network. Depending on the configuration used, node IDs can look like a	105	network. Depending on the configuration used, node IDs can look like a
90	hostname, a hostname and a port, or a random string. AnyEvent::MP itself	106	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
91	doesn't interpret node IDs in any way.	107	doesn't interpret node IDs in any way except to uniquely identify a node.
92		108
93	=item binds - C<ip:port>	109	=item binds - C<ip:port>
94		110
95	Nodes can only talk to each other by creating some kind of connection to	111	Nodes can only talk to each other by creating some kind of connection to
96	each other. To do this, nodes should listen on one or more local transport	112	each other. To do this, nodes should listen on one or more local transport
		113	endpoints - binds.
		114
97	endpoints - binds. Currently, only standard C<ip:port> specifications can	115	Currently, only standard C<ip:port> specifications can be used, which
98	be used, which specify TCP ports to listen on.	116	specify TCP ports to listen on. So a bind is basically just a tcp socket
		117	in listening mode thta accepts conenctions form other nodes.
99		118
100	=item seed nodes	119	=item seed nodes
101		120
102	When a node starts, it knows nothing about the network. To teach the node	121	When a node starts, it knows nothing about the network it is in - it
103	about the network it first has to contact some other node within the	122	needs to connect to at least one other node that is already in the
104	network. This node is called a seed.	123	network. These other nodes are called "seed nodes".
105		124
106	Apart from the fact that other nodes know them as seed nodes and they have	125	Seed nodes themselves are not special - they are seed nodes only because
107	to have fixed listening addresses, seed nodes are perfectly normal nodes -	126	some other node I<uses> them as such, but any node can be used as seed
108	any node can function as a seed node for others.	127	node for other nodes, and eahc node cna use a different set of seed nodes.
109		128
110	In addition to discovering the network, seed nodes are also used to	129	In addition to discovering the network, seed nodes are also used to
111	maintain the network and to connect nodes that otherwise would have	130	maintain the network - all nodes using the same seed node form are part of
112	trouble connecting. They form the backbone of an AnyEvent::MP network.	131	the same network. If a network is split into multiple subnets because e.g.
		132	the network link between the parts goes down, then using the same seed
		133	nodes for all nodes ensures that eventually the subnets get merged again.
113		134
114	Seed nodes are expected to be long-running, and at least one seed node	135	Seed nodes are expected to be long-running, and at least one seed node
115	should always be available. They should also be relatively responsive - a	136	should always be available. They should also be relatively responsive - a
116	seed node that blocks for long periods will slow down everybody else.	137	seed node that blocks for long periods will slow down everybody else.
117		138
		139	For small networks, it's best if every node uses the same set of seed
		140	nodes. For large networks, it can be useful to specify "regional" seed
		141	nodes for most nodes in an area, and use all seed nodes as seed nodes for
		142	each other. What's important is that all seed nodes connections form a
		143	complete graph, so that the network cannot split into separate subnets
		144	forever.
		145
		146	Seed nodes are represented by seed IDs.
		147
118	=item seeds - C<host:port>	148	=item seed IDs - C<host:port>
119		149
120	Seeds are transport endpoint(s) (usually a hostname/IP address and a	150	Seed IDs are transport endpoint(s) (usually a hostname/IP address and a
121	TCP port) of nodes thta should be used as seed nodes.	151	TCP port) of nodes that should be used as seed nodes.
122		152
123	The nodes listening on those endpoints are expected to be long-running,	153	=item global nodes
124	and at least one of those should always be available. When nodes run out	154
125	of connections (e.g. due to a network error), they try to re-establish	155	An AEMP network needs a discovery service - nodes need to know how to
126	connections to some seednodes again to join the network.	156	connect to other nodes they only know by name. In addition, AEMP offers a
		157	distributed "group database", which maps group names to a list of strings
		158	- for example, to register worker ports.
		159
		160	A network needs at least one global node to work, and allows every node to
		161	be a global node.
		162
		163	Any node that loads the L<AnyEvent::MP::Global> module becomes a global
		164	node and tries to keep connections to all other nodes. So while it can
		165	make sense to make every node "global" in small networks, it usually makes
		166	sense to only make seed nodes into global nodes in large networks (nodes
		167	keep connections to seed nodes and global nodes, so makign them the same
		168	reduces overhead).
127		169
128	=back	170	=back
129		171
130	=head1 VARIABLES/FUNCTIONS	172	=head1 VARIABLES/FUNCTIONS
131		173
…		…
133		175
134	=cut	176	=cut
135		177
136	package AnyEvent::MP;	178	package AnyEvent::MP;
137		179
		180	use AnyEvent::MP::Config ();
138	use AnyEvent::MP::Kernel;	181	use AnyEvent::MP::Kernel;
		182	use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID);
139		183
140	use common::sense;	184	use common::sense;
141		185
142	use Carp ();	186	use Carp ();
143		187
144	use AE ();	188	use AE ();
145		189
146	use base "Exporter";	190	use base "Exporter";
147		191
148	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	192	our $VERSION = $AnyEvent::MP::Config::VERSION;
149		193
150	our @EXPORT = qw(	194	our @EXPORT = qw(
151	NODE $NODE *SELF node_of after	195	NODE $NODE *SELF node_of after
152	configure	196	configure
153	snd rcv mon mon_guard kil reg psub spawn cal	197	snd rcv mon mon_guard kil psub peval spawn cal
154	port	198	port
155	);	199	);
156		200
157	our $SELF;	201	our $SELF;
158		202
…		…
181	to know is its own name, and optionally it should know the addresses of	225	to know is its own name, and optionally it should know the addresses of
182	some other nodes in the network to discover other nodes.	226	some other nodes in the network to discover other nodes.
183		227
184	This function configures a node - it must be called exactly once (or	228	This function configures a node - it must be called exactly once (or
185	never) before calling other AnyEvent::MP functions.	229	never) before calling other AnyEvent::MP functions.
		230
		231	The key/value pairs are basically the same ones as documented for the
		232	F<aemp> command line utility (sans the set/del prefix), with two additions:
		233
		234	=over 4
		235
		236	=item norc => $boolean (default false)
		237
		238	If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
		239	be consulted - all configuraiton options must be specified in the
		240	C<configure> call.
		241
		242	=item force => $boolean (default false)
		243
		244	IF true, then the values specified in the C<configure> will take
		245	precedence over any values configured via the rc file. The default is for
		246	the rc file to override any options specified in the program.
		247
		248	=back
186		249
187	=over 4	250	=over 4
188		251
189	=item step 1, gathering configuration from profiles	252	=item step 1, gathering configuration from profiles
190		253
…		…
204	That means that the values specified in the profile have highest priority	267	That means that the values specified in the profile have highest priority
205	and the values specified directly via C<configure> have lowest priority,	268	and the values specified directly via C<configure> have lowest priority,
206	and can only be used to specify defaults.	269	and can only be used to specify defaults.
207		270
208	If the profile specifies a node ID, then this will become the node ID of	271	If the profile specifies a node ID, then this will become the node ID of
209	this process. If not, then the profile name will be used as node ID. The	272	this process. If not, then the profile name will be used as node ID, with
210	special node ID of C<anon/> will be replaced by a random node ID.	273	a slash (C</>) attached.
		274
		275	If the node ID (or profile name) ends with a slash (C</>), then a random
		276	string is appended to make it unique.
211		277
212	=item step 2, bind listener sockets	278	=item step 2, bind listener sockets
213		279
214	The next step is to look up the binds in the profile, followed by binding	280	The next step is to look up the binds in the profile, followed by binding
215	aemp protocol listeners on all binds specified (it is possible and valid	281	aemp protocol listeners on all binds specified (it is possible and valid
…		…
221	used, meaning the node will bind on a dynamically-assigned port on every	287	used, meaning the node will bind on a dynamically-assigned port on every
222	local IP address it finds.	288	local IP address it finds.
223		289
224	=item step 3, connect to seed nodes	290	=item step 3, connect to seed nodes
225		291
226	As the last step, the seeds list from the profile is passed to the	292	As the last step, the seed ID list from the profile is passed to the
227	L<AnyEvent::MP::Global> module, which will then use it to keep	293	L<AnyEvent::MP::Global> module, which will then use it to keep
228	connectivity with at least one node at any point in time.	294	connectivity with at least one node at any point in time.
229		295
230	=back	296	=back
231		297
…		…
237	Example: become an anonymous node. This form is often used for commandline	303	Example: become an anonymous node. This form is often used for commandline
238	clients.	304	clients.
239		305
240	configure nodeid => "anon/";	306	configure nodeid => "anon/";
241		307
242	Example: configure a node using a profile called seed, which si suitable	308	Example: configure a node using a profile called seed, which is suitable
243	for a seed node as it binds on all local addresses on a fixed port (4040,	309	for a seed node as it binds on all local addresses on a fixed port (4040,
244	customary for aemp).	310	customary for aemp).
245		311
246	# use the aemp commandline utility	312	# use the aemp commandline utility
247	# aemp profile seed nodeid anon/ binds '*:4040'	313	# aemp profile seed binds '*:4040'
248		314
249	# then use it	315	# then use it
250	configure profile => "seed";	316	configure profile => "seed";
251		317
252	# or simply use aemp from the shell again:	318	# or simply use aemp from the shell again:
…		…
322	sub _kilme {	388	sub _kilme {
323	die "received message on port without callback";	389	die "received message on port without callback";
324	}	390	}
325		391
326	sub port(;&) {	392	sub port(;&) {
327	my $id = "$UNIQ." . $ID++;	393	my $id = "$UNIQ." . ++$ID;
328	my $port = "$NODE#$id";	394	my $port = "$NODE#$id";
329		395
330	rcv $port, shift \|\| \&_kilme;	396	rcv $port, shift \|\| \&_kilme;
331		397
332	$port	398	$port
…		…
371	msg1 => sub { ... },	437	msg1 => sub { ... },
372	...	438	...
373	;	439	;
374		440
375	Example: temporarily register a rcv callback for a tag matching some port	441	Example: temporarily register a rcv callback for a tag matching some port
376	(e.g. for a rpc reply) and unregister it after a message was received.	442	(e.g. for an rpc reply) and unregister it after a message was received.
377		443
378	rcv $port, $otherport => sub {	444	rcv $port, $otherport => sub {
379	my @reply = @_;	445	my @reply = @_;
380		446
381	rcv $SELF, $otherport;	447	rcv $SELF, $otherport;
…		…
394	if (ref $_[0]) {	460	if (ref $_[0]) {
395	if (my $self = $PORT_DATA{$portid}) {	461	if (my $self = $PORT_DATA{$portid}) {
396	"AnyEvent::MP::Port" eq ref $self	462	"AnyEvent::MP::Port" eq ref $self
397	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	463	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
398		464
399	$self->[2] = shift;	465	$self->[0] = shift;
400	} else {	466	} else {
401	my $cb = shift;	467	my $cb = shift;
402	$PORT{$portid} = sub {	468	$PORT{$portid} = sub {
403	local $SELF = $port;	469	local $SELF = $port;
404	eval { &$cb }; _self_die if $@;	470	eval { &$cb }; _self_die if $@;
405	};	471	};
406	}	472	}
407	} elsif (defined $_[0]) {	473	} elsif (defined $_[0]) {
408	my $self = $PORT_DATA{$portid} \|\|= do {	474	my $self = $PORT_DATA{$portid} \|\|= do {
409	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	475	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
410		476
411	$PORT{$portid} = sub {	477	$PORT{$portid} = sub {
412	local $SELF = $port;	478	local $SELF = $port;
413		479
414	if (my $cb = $self->[1]{$_[0]}) {	480	if (my $cb = $self->[1]{$_[0]}) {
…		…
436	}	502	}
437		503
438	$port	504	$port
439	}	505	}
440		506
		507	=item peval $port, $coderef[, @args]
		508
		509	Evaluates the given C<$codref> within the contetx of C<$port>, that is,
		510	when the code throews an exception the C<$port> will be killed.
		511
		512	Any remaining args will be passed to the callback. Any return values will
		513	be returned to the caller.
		514
		515	This is useful when you temporarily want to execute code in the context of
		516	a port.
		517
		518	Example: create a port and run some initialisation code in it's context.
		519
		520	my $port = port { ... };
		521
		522	peval $port, sub {
		523	init
		524	or die "unable to init";
		525	};
		526
		527	=cut
		528
		529	sub peval($$) {
		530	local $SELF = shift;
		531	my $cb = shift;
		532
		533	if (wantarray) {
		534	my @res = eval { &$cb };
		535	_self_die if $@;
		536	@res
		537	} else {
		538	my $res = eval { &$cb };
		539	_self_die if $@;
		540	$res
		541	}
		542	}
		543
441	=item $closure = psub { BLOCK }	544	=item $closure = psub { BLOCK }
442		545
443	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	546	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
444	closure is executed, sets up the environment in the same way as in C<rcv>	547	closure is executed, sets up the environment in the same way as in C<rcv>
445	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.	548	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		549
		550	The effect is basically as if it returned C<< sub { peval $SELF, sub {
		551	BLOCK }, @_ } >>.
446		552
447	This is useful when you register callbacks from C<rcv> callbacks:	553	This is useful when you register callbacks from C<rcv> callbacks:
448		554
449	rcv delayed_reply => sub {	555	rcv delayed_reply => sub {
450	my ($delay, @reply) = @_;	556	my ($delay, @reply) = @_;
…		…
523	delivered again.	629	delivered again.
524		630
525	Inter-host-connection timeouts and monitoring depend on the transport	631	Inter-host-connection timeouts and monitoring depend on the transport
526	used. The only transport currently implemented is TCP, and AnyEvent::MP	632	used. The only transport currently implemented is TCP, and AnyEvent::MP
527	relies on TCP to detect node-downs (this can take 10-15 minutes on a	633	relies on TCP to detect node-downs (this can take 10-15 minutes on a
528	non-idle connection, and usually around two hours for idle conenctions).	634	non-idle connection, and usually around two hours for idle connections).
529		635
530	This means that monitoring is good for program errors and cleaning up	636	This means that monitoring is good for program errors and cleaning up
531	stuff eventually, but they are no replacement for a timeout when you need	637	stuff eventually, but they are no replacement for a timeout when you need
532	to ensure some maximum latency.	638	to ensure some maximum latency.
533		639
…		…
565	}	671	}
566		672
567	$node->monitor ($port, $cb);	673	$node->monitor ($port, $cb);
568		674
569	defined wantarray	675	defined wantarray
570	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	676	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
571	}	677	}
572		678
573	=item $guard = mon_guard $port, $ref, $ref...	679	=item $guard = mon_guard $port, $ref, $ref...
574		680
575	Monitors the given C<$port> and keeps the passed references. When the port	681	Monitors the given C<$port> and keeps the passed references. When the port
…		…
598		704
599	=item kil $port[, @reason]	705	=item kil $port[, @reason]
600		706
601	Kill the specified port with the given C<@reason>.	707	Kill the specified port with the given C<@reason>.
602		708
603	If no C<@reason> is specified, then the port is killed "normally" (ports	709	If no C<@reason> is specified, then the port is killed "normally" -
604	monitoring other ports will not necessarily die because a port dies	710	monitor callback will be invoked, but the kil will not cause linked ports
605	"normally").	711	(C<mon $mport, $lport> form) to get killed.
606		712
607	Otherwise, linked ports get killed with the same reason (second form of	713	If a C<@reason> is specified, then linked ports (C<mon $mport, $lport>
608	C<mon>, see above).	714	form) get killed with the same reason.
609		715
610	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	716	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
611	will be reported as reason C<< die => $@ >>.	717	will be reported as reason C<< die => $@ >>.
612		718
613	Transport/communication errors are reported as C<< transport_error =>	719	Transport/communication errors are reported as C<< transport_error =>
…		…
679	}	785	}
680		786
681	sub spawn(@) {	787	sub spawn(@) {
682	my ($nodeid, undef) = split /#/, shift, 2;	788	my ($nodeid, undef) = split /#/, shift, 2;
683		789
684	my $id = "$RUNIQ." . $ID++;	790	my $id = "$RUNIQ." . ++$ID;
685		791
686	$_[0] =~ /::/	792	$_[0] =~ /::/
687	or Carp::croak "spawn init function must be a fully-qualified name, caught";	793	or Carp::croak "spawn init function must be a fully-qualified name, caught";
688		794
689	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	795	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
690		796
691	"$nodeid#$id"	797	"$nodeid#$id"
692	}	798	}
		799
693		800
694	=item after $timeout, @msg	801	=item after $timeout, @msg
695		802
696	=item after $timeout, $callback	803	=item after $timeout, $callback
697		804
…		…
727		834
728	If an optional time-out (in seconds) is given and it is not C<undef>,	835	If an optional time-out (in seconds) is given and it is not C<undef>,
729	then the callback will be called without any arguments after the time-out	836	then the callback will be called without any arguments after the time-out
730	elapsed and the port is C<kil>ed.	837	elapsed and the port is C<kil>ed.
731		838
732	If no time-out is given, then the local port will monitor the remote port	839	If no time-out is given (or it is C<undef>), then the local port will
733	instead, so it eventually gets cleaned-up.	840	monitor the remote port instead, so it eventually gets cleaned-up.
734		841
735	Currently this function returns the temporary port, but this "feature"	842	Currently this function returns the temporary port, but this "feature"
736	might go in future versions unless you can make a convincing case that	843	might go in future versions unless you can make a convincing case that
737	this is indeed useful for something.	844	this is indeed useful for something.
738		845
…		…
774	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	881	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
775	== aemp node, Erlang process == aemp port), so many of the documents and	882	== aemp node, Erlang process == aemp port), so many of the documents and
776	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	883	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
777	sample:	884	sample:
778		885
779	http://www.Erlang.se/doc/programming_rules.shtml	886	http://www.erlang.se/doc/programming_rules.shtml
780	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	887	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
781	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6	888	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
782	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	889	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
783		890
784	Despite the similarities, there are also some important differences:	891	Despite the similarities, there are also some important differences:
785		892
786	=over 4	893	=over 4
787		894
788	=item * Node IDs are arbitrary strings in AEMP.	895	=item * Node IDs are arbitrary strings in AEMP.
789		896
790	Erlang relies on special naming and DNS to work everywhere in the same	897	Erlang relies on special naming and DNS to work everywhere in the same
791	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by	898	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
792	configuration or DNS), but will otherwise discover other odes itself.	899	configuration or DNS), and possibly the addresses of some seed nodes, but
		900	will otherwise discover other nodes (and their IDs) itself.
793		901
794	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	902	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
795	uses "local ports are like remote ports".	903	uses "local ports are like remote ports".
796		904
797	The failure modes for local ports are quite different (runtime errors	905	The failure modes for local ports are quite different (runtime errors
…		…
806	ports being the special case/exception, where transport errors cannot	914	ports being the special case/exception, where transport errors cannot
807	occur.	915	occur.
808		916
809	=item * Erlang uses processes and a mailbox, AEMP does not queue.	917	=item * Erlang uses processes and a mailbox, AEMP does not queue.
810		918
811	Erlang uses processes that selectively receive messages, and therefore	919	Erlang uses processes that selectively receive messages out of order, and
812	needs a queue. AEMP is event based, queuing messages would serve no	920	therefore needs a queue. AEMP is event based, queuing messages would serve
813	useful purpose. For the same reason the pattern-matching abilities of	921	no useful purpose. For the same reason the pattern-matching abilities
814	AnyEvent::MP are more limited, as there is little need to be able to	922	of AnyEvent::MP are more limited, as there is little need to be able to
815	filter messages without dequeuing them.	923	filter messages without dequeuing them.
816		924
817	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	925	This is not a philosophical difference, but simply stems from AnyEvent::MP
		926	being event-based, while Erlang is process-based.
		927
		928	You cna have a look at L<Coro::MP> for a more Erlang-like process model on
		929	top of AEMP and Coro threads.
818		930
819	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	931	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
820		932
821	Sending messages in Erlang is synchronous and blocks the process (and	933	Sending messages in Erlang is synchronous and blocks the process until
		934	a conenction has been established and the message sent (and so does not
822	so does not need a queue that can overflow). AEMP sends are immediate,	935	need a queue that can overflow). AEMP sends return immediately, connection
823	connection establishment is handled in the background.	936	establishment is handled in the background.
824		937
825	=item * Erlang suffers from silent message loss, AEMP does not.	938	=item * Erlang suffers from silent message loss, AEMP does not.
826		939
827	Erlang makes few guarantees on messages delivery - messages can get lost	940	Erlang implements few guarantees on messages delivery - messages can get
828	without any of the processes realising it (i.e. you send messages a, b,	941	lost without any of the processes realising it (i.e. you send messages a,
829	and c, and the other side only receives messages a and c).	942	b, and c, and the other side only receives messages a and c).
830		943
831	AEMP guarantees correct ordering, and the guarantee that after one message	944	AEMP guarantees (modulo hardware errors) correct ordering, and the
832	is lost, all following ones sent to the same port are lost as well, until	945	guarantee that after one message is lost, all following ones sent to the
833	monitoring raises an error, so there are no silent "holes" in the message	946	same port are lost as well, until monitoring raises an error, so there are
834	sequence.	947	no silent "holes" in the message sequence.
		948
		949	If you want your software to be very reliable, you have to cope with
		950	corrupted and even out-of-order messages in both Erlang and AEMP. AEMP
		951	simply tries to work better in common error cases, such as when a network
		952	link goes down.
835		953
836	=item * Erlang can send messages to the wrong port, AEMP does not.	954	=item * Erlang can send messages to the wrong port, AEMP does not.
837		955
838	In Erlang it is quite likely that a node that restarts reuses a process ID	956	In Erlang it is quite likely that a node that restarts reuses an Erlang
839	known to other nodes for a completely different process, causing messages	957	process ID known to other nodes for a completely different process,
840	destined for that process to end up in an unrelated process.	958	causing messages destined for that process to end up in an unrelated
		959	process.
841		960
842	AEMP never reuses port IDs, so old messages or old port IDs floating	961	AEMP does not reuse port IDs, so old messages or old port IDs floating
843	around in the network will not be sent to an unrelated port.	962	around in the network will not be sent to an unrelated port.
844		963
845	=item * Erlang uses unprotected connections, AEMP uses secure	964	=item * Erlang uses unprotected connections, AEMP uses secure
846	authentication and can use TLS.	965	authentication and can use TLS.
847		966
…		…
850		969
851	=item * The AEMP protocol is optimised for both text-based and binary	970	=item * The AEMP protocol is optimised for both text-based and binary
852	communications.	971	communications.
853		972
854	The AEMP protocol, unlike the Erlang protocol, supports both programming	973	The AEMP protocol, unlike the Erlang protocol, supports both programming
855	language independent text-only protocols (good for debugging) and binary,	974	language independent text-only protocols (good for debugging), and binary,
856	language-specific serialisers (e.g. Storable). By default, unless TLS is	975	language-specific serialisers (e.g. Storable). By default, unless TLS is
857	used, the protocol is actually completely text-based.	976	used, the protocol is actually completely text-based.
858		977
859	It has also been carefully designed to be implementable in other languages	978	It has also been carefully designed to be implementable in other languages
860	with a minimum of work while gracefully degrading functionality to make the	979	with a minimum of work while gracefully degrading functionality to make the
861	protocol simple.	980	protocol simple.
862		981
863	=item * AEMP has more flexible monitoring options than Erlang.	982	=item * AEMP has more flexible monitoring options than Erlang.
864		983
865	In Erlang, you can chose to receive I<all> exit signals as messages	984	In Erlang, you can chose to receive I<all> exit signals as messages or
866	or I<none>, there is no in-between, so monitoring single processes is	985	I<none>, there is no in-between, so monitoring single Erlang processes is
867	difficult to implement. Monitoring in AEMP is more flexible than in	986	difficult to implement.
868	Erlang, as one can choose between automatic kill, exit message or callback	987
869	on a per-process basis.	988	Monitoring in AEMP is more flexible than in Erlang, as one can choose
		989	between automatic kill, exit message or callback on a per-port basis.
870		990
871	=item * Erlang tries to hide remote/local connections, AEMP does not.	991	=item * Erlang tries to hide remote/local connections, AEMP does not.
872		992
873	Monitoring in Erlang is not an indicator of process death/crashes, in the	993	Monitoring in Erlang is not an indicator of process death/crashes, in the
874	same way as linking is (except linking is unreliable in Erlang).	994	same way as linking is (except linking is unreliable in Erlang).
…		…
896	overhead, as well as having to keep a proxy object everywhere.	1016	overhead, as well as having to keep a proxy object everywhere.
897		1017
898	Strings can easily be printed, easily serialised etc. and need no special	1018	Strings can easily be printed, easily serialised etc. and need no special
899	procedures to be "valid".	1019	procedures to be "valid".
900		1020
901	And as a result, a miniport consists of a single closure stored in a	1021	And as a result, a port with just a default receiver consists of a single
902	global hash - it can't become much cheaper.	1022	code reference stored in a global hash - it can't become much cheaper.
903		1023
904	=item Why favour JSON, why not a real serialising format such as Storable?	1024	=item Why favour JSON, why not a real serialising format such as Storable?
905		1025
906	In fact, any AnyEvent::MP node will happily accept Storable as framing	1026	In fact, any AnyEvent::MP node will happily accept Storable as framing
907	format, but currently there is no way to make a node use Storable by	1027	format, but currently there is no way to make a node use Storable by
…		…
923		1043
924	L<AnyEvent::MP::Intro> - a gentle introduction.	1044	L<AnyEvent::MP::Intro> - a gentle introduction.
925		1045
926	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1046	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
927		1047
928	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	1048	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
929	your applications.	1049	your applications.
		1050
		1051	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
930		1052
931	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from	1053	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
932	all nodes.	1054	all nodes.
933		1055
934	L<AnyEvent>.	1056	L<AnyEvent>.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.89 by root, Fri Sep 11 16:47:14 2009 UTC vs. Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.89 by root, Fri Sep 11 16:47:14 2009 UTC vs.
Revision 1.122 by root, Wed Feb 29 18:44:59 2012 UTC