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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.85 by root, Tue Sep 8 01:54:13 2009 UTC vs.
Revision 1.142 by root, Fri Mar 23 13:44:01 2012 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 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 $port, $cb->(@msg) # callback is invoked on death
37	mon $port, $otherport # kill otherport on abnormal death	41	mon $port, $localport # kill localport on abnormal death
38	mon $port, $otherport, @msg # send message on death	42	mon $port, $localport, @msg # send message on death
39		43
40	=head1 CURRENT STATUS	44	# temporarily execute code in port context
		45	peval $port, sub { die "kill the port!" };
41		46
42	bin/aemp - stable.	47	# execute callbacks in $SELF port context
43	AnyEvent::MP - stable API, should work.	48	my $timer = AE::timer 1, 0, psub {
44	AnyEvent::MP::Intro - explains most concepts.	49	die "kill the port, delayed";
45	AnyEvent::MP::Kernel - mostly stable.	50	};
46	AnyEvent::MP::Global - stable but incomplete, protocol not yet final.
47
48	stay tuned.
49		51
50	=head1 DESCRIPTION	52	=head1 DESCRIPTION
51		53
52	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
53		55
…		…
68		70
69	Ports allow you to register C<rcv> handlers that can match all or just	71	Ports allow you to register C<rcv> handlers that can match all or just
70	some messages. Messages send to ports will not be queued, regardless of	72	some messages. Messages send to ports will not be queued, regardless of
71	anything was listening for them or not.	73	anything was listening for them or not.
72		74
		75	Ports are represented by (printable) strings called "port IDs".
		76
73	=item port ID - C<nodeid#portname>	77	=item port ID - C<nodeid#portname>
74		78
75	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as	79	A port ID is the concatenation of a node ID, a hash-mark (C<#>)
76	separator, and a port name (a printable string of unspecified format).	80	as separator, and a port name (a printable string of unspecified
		81	format created by AnyEvent::MP).
77		82
78	=item node	83	=item node
79		84
80	A node is a single process containing at least one port - the node port,	85	A node is a single process containing at least one port - the node port,
81	which enables nodes to manage each other remotely, and to create new	86	which enables nodes to manage each other remotely, and to create new
82	ports.	87	ports.
83		88
84	Nodes are either public (have one or more listening ports) or private	89	Nodes are either public (have one or more listening ports) or private
85	(no listening ports). Private nodes cannot talk to other private nodes	90	(no listening ports). Private nodes cannot talk to other private nodes
86	currently.	91	currently, but all nodes can talk to public nodes.
87		92
		93	Nodes is represented by (printable) strings called "node IDs".
		94
88	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>	95	=item node ID - C<[A-Za-z0-9_\-.:]*>
89		96
90	A node ID is a string that uniquely identifies the node within a	97	A node ID is a string that uniquely identifies the node within a
91	network. Depending on the configuration used, node IDs can look like a	98	network. Depending on the configuration used, node IDs can look like a
92	hostname, a hostname and a port, or a random string. AnyEvent::MP itself	99	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
93	doesn't interpret node IDs in any way.	100	doesn't interpret node IDs in any way except to uniquely identify a node.
94		101
95	=item binds - C<ip:port>	102	=item binds - C<ip:port>
96		103
97	Nodes can only talk to each other by creating some kind of connection to	104	Nodes can only talk to each other by creating some kind of connection to
98	each other. To do this, nodes should listen on one or more local transport	105	each other. To do this, nodes should listen on one or more local transport
		106	endpoints - binds.
		107
99	endpoints - binds. Currently, only standard C<ip:port> specifications can	108	Currently, only standard C<ip:port> specifications can be used, which
100	be used, which specify TCP ports to listen on.	109	specify TCP ports to listen on. So a bind is basically just a tcp socket
		110	in listening mode thta accepts conenctions form other nodes.
101		111
102	=item seed nodes	112	=item seed nodes
103		113
104	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 it is in - it
105	about the network it first has to contact some other node within the	115	needs to connect to at least one other node that is already in the
106	network. This node is called a seed.	116	network. These other nodes are called "seed nodes".
107		117
108	Apart from the fact that other nodes know them as seed nodes and they have	118	Seed nodes themselves are not special - they are seed nodes only because
109	to have fixed listening addresses, seed nodes are perfectly normal nodes -	119	some other node I<uses> them as such, but any node can be used as seed
110	any node can function as a seed node for others.	120	node for other nodes, and eahc node cna use a different set of seed nodes.
111		121
112	In addition to discovering the network, seed nodes are also used to	122	In addition to discovering the network, seed nodes are also used to
113	maintain the network and to connect nodes that otherwise would have	123	maintain the network - all nodes using the same seed node form are part of
114	trouble connecting. They form the backbone of the AnyEvent::MP network.	124	the same network. If a network is split into multiple subnets because e.g.
		125	the network link between the parts goes down, then using the same seed
		126	nodes for all nodes ensures that eventually the subnets get merged again.
115		127
116	Seed nodes are expected to be long-running, and at least one seed node	128	Seed nodes are expected to be long-running, and at least one seed node
117	should always be available. They should also be relatively responsive - a	129	should always be available. They should also be relatively responsive - a
118	seed node that blocks for long periods will slow down everybody else.	130	seed node that blocks for long periods will slow down everybody else.
119		131
		132	For small networks, it's best if every node uses the same set of seed
		133	nodes. For large networks, it can be useful to specify "regional" seed
		134	nodes for most nodes in an area, and use all seed nodes as seed nodes for
		135	each other. What's important is that all seed nodes connections form a
		136	complete graph, so that the network cannot split into separate subnets
		137	forever.
		138
		139	Seed nodes are represented by seed IDs.
		140
120	=item seeds - C<host:port>	141	=item seed IDs - C<host:port>
121		142
122	Seeds are transport endpoint(s) (usually a hostname/IP address and a	143	Seed IDs are transport endpoint(s) (usually a hostname/IP address and a
123	TCP port) of nodes thta should be used as seed nodes.	144	TCP port) of nodes that should be used as seed nodes.
124		145
125	The nodes listening on those endpoints are expected to be long-running,	146	=item global nodes
126	and at least one of those should always be available. When nodes run out	147
127	of connections (e.g. due to a network error), they try to re-establish	148	An AEMP network needs a discovery service - nodes need to know how to
128	connections to some seednodes again to join the network.	149	connect to other nodes they only know by name. In addition, AEMP offers a
		150	distributed "group database", which maps group names to a list of strings
		151	- for example, to register worker ports.
		152
		153	A network needs at least one global node to work, and allows every node to
		154	be a global node.
		155
		156	Any node that loads the L<AnyEvent::MP::Global> module becomes a global
		157	node and tries to keep connections to all other nodes. So while it can
		158	make sense to make every node "global" in small networks, it usually makes
		159	sense to only make seed nodes into global nodes in large networks (nodes
		160	keep connections to seed nodes and global nodes, so makign them the same
		161	reduces overhead).
129		162
130	=back	163	=back
131		164
132	=head1 VARIABLES/FUNCTIONS	165	=head1 VARIABLES/FUNCTIONS
133		166
…		…
135		168
136	=cut	169	=cut
137		170
138	package AnyEvent::MP;	171	package AnyEvent::MP;
139		172
		173	use AnyEvent::MP::Config ();
140	use AnyEvent::MP::Kernel;	174	use AnyEvent::MP::Kernel;
		175	use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID);
141		176
142	use common::sense;	177	use common::sense;
143		178
144	use Carp ();	179	use Carp ();
145		180
146	use AE ();	181	use AnyEvent ();
		182	use Guard ();
147		183
148	use base "Exporter";	184	use base "Exporter";
149		185
150	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	186	our $VERSION = $AnyEvent::MP::Config::VERSION;
151		187
152	our @EXPORT = qw(	188	our @EXPORT = qw(
153	NODE $NODE *SELF node_of after	189	NODE $NODE *SELF node_of after
154	configure	190	configure
155	snd rcv mon mon_guard kil reg psub spawn	191	snd rcv mon mon_guard kil psub peval spawn cal
156	port	192	port
		193	db_set db_del db_reg
		194	db_mon db_family db_keys db_values
157	);	195	);
158		196
159	our $SELF;	197	our $SELF;
160		198
161	sub _self_die() {	199	sub _self_die() {
…		…
184	some other nodes in the network to discover other nodes.	222	some other nodes in the network to discover other nodes.
185		223
186	This function configures a node - it must be called exactly once (or	224	This function configures a node - it must be called exactly once (or
187	never) before calling other AnyEvent::MP functions.	225	never) before calling other AnyEvent::MP functions.
188		226
		227	The key/value pairs are basically the same ones as documented for the
		228	F<aemp> command line utility (sans the set/del prefix), with these additions:
		229
		230	=over 4
		231
		232	=item norc => $boolean (default false)
		233
		234	If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
		235	be consulted - all configuraiton options must be specified in the
		236	C<configure> call.
		237
		238	=item force => $boolean (default false)
		239
		240	IF true, then the values specified in the C<configure> will take
		241	precedence over any values configured via the rc file. The default is for
		242	the rc file to override any options specified in the program.
		243
		244	=back
		245
189	=over 4	246	=over 4
190		247
191	=item step 1, gathering configuration from profiles	248	=item step 1, gathering configuration from profiles
192		249
193	The function first looks up a profile in the aemp configuration (see the	250	The function first looks up a profile in the aemp configuration (see the
…		…
206	That means that the values specified in the profile have highest priority	263	That means that the values specified in the profile have highest priority
207	and the values specified directly via C<configure> have lowest priority,	264	and the values specified directly via C<configure> have lowest priority,
208	and can only be used to specify defaults.	265	and can only be used to specify defaults.
209		266
210	If the profile specifies a node ID, then this will become the node ID of	267	If the profile specifies a node ID, then this will become the node ID of
211	this process. If not, then the profile name will be used as node ID. The	268	this process. If not, then the profile name will be used as node ID, with
212	special node ID of C<anon/> will be replaced by a random node ID.	269	a unique randoms tring (C</%u>) appended.
		270
		271	The node ID can contain some C<%> sequences that are expanded: C<%n>
		272	is expanded to the local nodename, C<%u> is replaced by a random
		273	strign to make the node unique. For example, the F<aemp> commandline
		274	utility uses C<aemp/%n/%u> as nodename, which might expand to
		275	C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
213		276
214	=item step 2, bind listener sockets	277	=item step 2, bind listener sockets
215		278
216	The next step is to look up the binds in the profile, followed by binding	279	The next step is to look up the binds in the profile, followed by binding
217	aemp protocol listeners on all binds specified (it is possible and valid	280	aemp protocol listeners on all binds specified (it is possible and valid
…		…
223	used, meaning the node will bind on a dynamically-assigned port on every	286	used, meaning the node will bind on a dynamically-assigned port on every
224	local IP address it finds.	287	local IP address it finds.
225		288
226	=item step 3, connect to seed nodes	289	=item step 3, connect to seed nodes
227		290
228	As the last step, the seeds list from the profile is passed to the	291	As the last step, the seed ID list from the profile is passed to the
229	L<AnyEvent::MP::Global> module, which will then use it to keep	292	L<AnyEvent::MP::Global> module, which will then use it to keep
230	connectivity with at least one node at any point in time.	293	connectivity with at least one node at any point in time.
231		294
232	=back	295	=back
233		296
234	Example: become a distributed node using the locla node name as profile.	297	Example: become a distributed node using the local node name as profile.
235	This should be the most common form of invocation for "daemon"-type nodes.	298	This should be the most common form of invocation for "daemon"-type nodes.
236		299
237	configure	300	configure
238		301
239	Example: become an anonymous node. This form is often used for commandline	302	Example: become a semi-anonymous node. This form is often used for
240	clients.	303	commandline clients.
241		304
242	configure nodeid => "anon/";	305	configure nodeid => "myscript/%n/%u";
243		306
244	Example: configure a node using a profile called seed, which si suitable	307	Example: configure a node using a profile called seed, which is suitable
245	for a seed node as it binds on all local addresses on a fixed port (4040,	308	for a seed node as it binds on all local addresses on a fixed port (4040,
246	customary for aemp).	309	customary for aemp).
247		310
248	# use the aemp commandline utility	311	# use the aemp commandline utility
249	# aemp profile seed nodeid anon/ binds '*:4040'	312	# aemp profile seed binds '*:4040'
250		313
251	# then use it	314	# then use it
252	configure profile => "seed";	315	configure profile => "seed";
253		316
254	# or simply use aemp from the shell again:	317	# or simply use aemp from the shell again:
…		…
319		382
320	=cut	383	=cut
321		384
322	sub rcv($@);	385	sub rcv($@);
323		386
324	sub _kilme {	387	my $KILME = sub {
325	die "received message on port without callback";	388	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
326	}	389	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		390	};
327		391
328	sub port(;&) {	392	sub port(;&) {
329	my $id = "$UNIQ." . $ID++;	393	my $id = $UNIQ . ++$ID;
330	my $port = "$NODE#$id";	394	my $port = "$NODE#$id";
331		395
332	rcv $port, shift \|\| \&_kilme;	396	rcv $port, shift \|\| $KILME;
333		397
334	$port	398	$port
335	}	399	}
336		400
337	=item rcv $local_port, $callback->(@msg)	401	=item rcv $local_port, $callback->(@msg)
…		…
342		406
343	The global C<$SELF> (exported by this module) contains C<$port> while	407	The global C<$SELF> (exported by this module) contains C<$port> while
344	executing the callback. Runtime errors during callback execution will	408	executing the callback. Runtime errors during callback execution will
345	result in the port being C<kil>ed.	409	result in the port being C<kil>ed.
346		410
347	The default callback received all messages not matched by a more specific	411	The default callback receives all messages not matched by a more specific
348	C<tag> match.	412	C<tag> match.
349		413
350	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	414	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
351		415
352	Register (or replace) callbacks to be called on messages starting with the	416	Register (or replace) callbacks to be called on messages starting with the
…		…
373	msg1 => sub { ... },	437	msg1 => sub { ... },
374	...	438	...
375	;	439	;
376		440
377	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
378	(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.
379		443
380	rcv $port, $otherport => sub {	444	rcv $port, $otherport => sub {
381	my @reply = @_;	445	my @reply = @_;
382		446
383	rcv $SELF, $otherport;	447	rcv $SELF, $otherport;
…		…
396	if (ref $_[0]) {	460	if (ref $_[0]) {
397	if (my $self = $PORT_DATA{$portid}) {	461	if (my $self = $PORT_DATA{$portid}) {
398	"AnyEvent::MP::Port" eq ref $self	462	"AnyEvent::MP::Port" eq ref $self
399	or Carp::croak "$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";
400		464
401	$self->[2] = shift;	465	$self->[0] = shift;
402	} else {	466	} else {
403	my $cb = shift;	467	my $cb = shift;
404	$PORT{$portid} = sub {	468	$PORT{$portid} = sub {
405	local $SELF = $port;	469	local $SELF = $port;
406	eval { &$cb }; _self_die if $@;	470	eval { &$cb }; _self_die if $@;
407	};	471	};
408	}	472	}
409	} elsif (defined $_[0]) {	473	} elsif (defined $_[0]) {
410	my $self = $PORT_DATA{$portid} \|\|= do {	474	my $self = $PORT_DATA{$portid} \|\|= do {
411	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	475	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
412		476
413	$PORT{$portid} = sub {	477	$PORT{$portid} = sub {
414	local $SELF = $port;	478	local $SELF = $port;
415		479
416	if (my $cb = $self->[1]{$_[0]}) {	480	if (my $cb = $self->[1]{$_[0]}) {
…		…
438	}	502	}
439		503
440	$port	504	$port
441	}	505	}
442		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
443	=item $closure = psub { BLOCK }	544	=item $closure = psub { BLOCK }
444		545
445	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
446	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>
447	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 }, @_ } >>.
448		552
449	This is useful when you register callbacks from C<rcv> callbacks:	553	This is useful when you register callbacks from C<rcv> callbacks:
450		554
451	rcv delayed_reply => sub {	555	rcv delayed_reply => sub {
452	my ($delay, @reply) = @_;	556	my ($delay, @reply) = @_;
…		…
476	$res	580	$res
477	}	581	}
478	}	582	}
479	}	583	}
480		584
		585	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
		586
		587	=item $guard = mon $port # kill $SELF when $port dies
		588
481	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies	589	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
482
483	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
484
485	=item $guard = mon $port # kill $SELF when $port dies
486		590
487	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies	591	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
488		592
489	Monitor the given port and do something when the port is killed or	593	Monitor the given port and do something when the port is killed or
490	messages to it were lost, and optionally return a guard that can be used	594	messages to it were lost, and optionally return a guard that can be used
491	to stop monitoring again.	595	to stop monitoring again.
492		596
		597	The first two forms distinguish between "normal" and "abnormal" kil's:
		598
		599	In the first form (another port given), if the C<$port> is C<kil>'ed with
		600	a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the
		601	same reason. That is, on "normal" kil's nothing happens, while under all
		602	other conditions, the other port is killed with the same reason.
		603
		604	The second form (kill self) is the same as the first form, except that
		605	C<$rvport> defaults to C<$SELF>.
		606
		607	The remaining forms don't distinguish between "normal" and "abnormal" kil's
		608	- it's up to the callback or receiver to check whether the C<@reason> is
		609	empty and act accordingly.
		610
493	In the first form (callback), the callback is simply called with any	611	In the third form (callback), the callback is simply called with any
494	number of C<@reason> elements (no @reason means that the port was deleted	612	number of C<@reason> elements (empty @reason means that the port was deleted
495	"normally"). Note also that I<< the callback B<must> never die >>, so use	613	"normally"). Note also that I<< the callback B<must> never die >>, so use
496	C<eval> if unsure.	614	C<eval> if unsure.
497		615
498	In the second form (another port given), the other port (C<$rcvport>)
499	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
500	"normal" kils nothing happens, while under all other conditions, the other
501	port is killed with the same reason.
502
503	The third form (kill self) is the same as the second form, except that
504	C<$rvport> defaults to C<$SELF>.
505
506	In the last form (message), a message of the form C<@msg, @reason> will be	616	In the last form (message), a message of the form C<$rcvport, @msg,
507	C<snd>.	617	@reason> will be C<snd>.
508		618
509	Monitoring-actions are one-shot: once messages are lost (and a monitoring	619	Monitoring-actions are one-shot: once messages are lost (and a monitoring
510	alert was raised), they are removed and will not trigger again.	620	alert was raised), they are removed and will not trigger again, even if it
		621	turns out that the port is still alive.
511		622
512	As a rule of thumb, monitoring requests should always monitor a port from	623	As a rule of thumb, monitoring requests should always monitor a remote
513	a local port (or callback). The reason is that kill messages might get	624	port locally (using a local C<$rcvport> or a callback). The reason is that
514	lost, just like any other message. Another less obvious reason is that	625	kill messages might get lost, just like any other message. Another less
515	even monitoring requests can get lost (for example, when the connection	626	obvious reason is that even monitoring requests can get lost (for example,
516	to the other node goes down permanently). When monitoring a port locally	627	when the connection to the other node goes down permanently). When
517	these problems do not exist.	628	monitoring a port locally these problems do not exist.
518		629
519	C<mon> effectively guarantees that, in the absence of hardware failures,	630	C<mon> effectively guarantees that, in the absence of hardware failures,
520	after starting the monitor, either all messages sent to the port will	631	after starting the monitor, either all messages sent to the port will
521	arrive, or the monitoring action will be invoked after possible message	632	arrive, or the monitoring action will be invoked after possible message
522	loss has been detected. No messages will be lost "in between" (after	633	loss has been detected. No messages will be lost "in between" (after
…		…
525	delivered again.	636	delivered again.
526		637
527	Inter-host-connection timeouts and monitoring depend on the transport	638	Inter-host-connection timeouts and monitoring depend on the transport
528	used. The only transport currently implemented is TCP, and AnyEvent::MP	639	used. The only transport currently implemented is TCP, and AnyEvent::MP
529	relies on TCP to detect node-downs (this can take 10-15 minutes on a	640	relies on TCP to detect node-downs (this can take 10-15 minutes on a
530	non-idle connection, and usually around two hours for idle conenctions).	641	non-idle connection, and usually around two hours for idle connections).
531		642
532	This means that monitoring is good for program errors and cleaning up	643	This means that monitoring is good for program errors and cleaning up
533	stuff eventually, but they are no replacement for a timeout when you need	644	stuff eventually, but they are no replacement for a timeout when you need
534	to ensure some maximum latency.	645	to ensure some maximum latency.
535		646
…		…
567	}	678	}
568		679
569	$node->monitor ($port, $cb);	680	$node->monitor ($port, $cb);
570		681
571	defined wantarray	682	defined wantarray
572	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	683	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
573	}	684	}
574		685
575	=item $guard = mon_guard $port, $ref, $ref...	686	=item $guard = mon_guard $port, $ref, $ref...
576		687
577	Monitors the given C<$port> and keeps the passed references. When the port	688	Monitors the given C<$port> and keeps the passed references. When the port
…		…
600		711
601	=item kil $port[, @reason]	712	=item kil $port[, @reason]
602		713
603	Kill the specified port with the given C<@reason>.	714	Kill the specified port with the given C<@reason>.
604		715
605	If no C<@reason> is specified, then the port is killed "normally" (ports	716	If no C<@reason> is specified, then the port is killed "normally" -
606	monitoring other ports will not necessarily die because a port dies	717	monitor callback will be invoked, but the kil will not cause linked ports
607	"normally").	718	(C<mon $mport, $lport> form) to get killed.
608		719
609	Otherwise, linked ports get killed with the same reason (second form of	720	If a C<@reason> is specified, then linked ports (C<mon $mport, $lport>
610	C<mon>, see above).	721	form) get killed with the same reason.
611		722
612	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	723	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
613	will be reported as reason C<< die => $@ >>.	724	will be reported as reason C<< die => $@ >>.
614		725
615	Transport/communication errors are reported as C<< transport_error =>	726	Transport/communication errors are reported as C<< transport_error =>
616	$message >>.	727	$message >>.
617		728
618	=cut	729	Common idioms:
		730
		731	# silently remove yourself, do not kill linked ports
		732	kil $SELF;
		733
		734	# report a failure in some detail
		735	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		736
		737	# do not waste much time with killing, just die when something goes wrong
		738	open my $fh, "<file"
		739	or die "file: $!";
619		740
620	=item $port = spawn $node, $initfunc[, @initdata]	741	=item $port = spawn $node, $initfunc[, @initdata]
621		742
622	Creates a port on the node C<$node> (which can also be a port ID, in which	743	Creates a port on the node C<$node> (which can also be a port ID, in which
623	case it's the node where that port resides).	744	case it's the node where that port resides).
…		…
681	}	802	}
682		803
683	sub spawn(@) {	804	sub spawn(@) {
684	my ($nodeid, undef) = split /#/, shift, 2;	805	my ($nodeid, undef) = split /#/, shift, 2;
685		806
686	my $id = "$RUNIQ." . $ID++;	807	my $id = $RUNIQ . ++$ID;
687		808
688	$_[0] =~ /::/	809	$_[0] =~ /::/
689	or Carp::croak "spawn init function must be a fully-qualified name, caught";	810	or Carp::croak "spawn init function must be a fully-qualified name, caught";
690		811
691	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	812	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
692		813
693	"$nodeid#$id"	814	"$nodeid#$id"
694	}	815	}
		816
695		817
696	=item after $timeout, @msg	818	=item after $timeout, @msg
697		819
698	=item after $timeout, $callback	820	=item after $timeout, $callback
699		821
…		…
715	? $action[0]()	837	? $action[0]()
716	: snd @action;	838	: snd @action;
717	};	839	};
718	}	840	}
719		841
		842	#=item $cb2 = timeout $seconds, $cb[, @args]
		843
		844	=item cal $port, @msg, $callback[, $timeout]
		845
		846	A simple form of RPC - sends a message to the given C<$port> with the
		847	given contents (C<@msg>), but adds a reply port to the message.
		848
		849	The reply port is created temporarily just for the purpose of receiving
		850	the reply, and will be C<kil>ed when no longer needed.
		851
		852	A reply message sent to the port is passed to the C<$callback> as-is.
		853
		854	If an optional time-out (in seconds) is given and it is not C<undef>,
		855	then the callback will be called without any arguments after the time-out
		856	elapsed and the port is C<kil>ed.
		857
		858	If no time-out is given (or it is C<undef>), then the local port will
		859	monitor the remote port instead, so it eventually gets cleaned-up.
		860
		861	Currently this function returns the temporary port, but this "feature"
		862	might go in future versions unless you can make a convincing case that
		863	this is indeed useful for something.
		864
		865	=cut
		866
		867	sub cal(@) {
		868	my $timeout = ref $_[-1] ? undef : pop;
		869	my $cb = pop;
		870
		871	my $port = port {
		872	undef $timeout;
		873	kil $SELF;
		874	&$cb;
		875	};
		876
		877	if (defined $timeout) {
		878	$timeout = AE::timer $timeout, 0, sub {
		879	undef $timeout;
		880	kil $port;
		881	$cb->();
		882	};
		883	} else {
		884	mon $_[0], sub {
		885	kil $port;
		886	$cb->();
		887	};
		888	}
		889
		890	push @_, $port;
		891	&snd;
		892
		893	$port
		894	}
		895
		896	=back
		897
		898	=head1 DISTRIBUTED DATABASE
		899
		900	AnyEvent::MP comes with a simple distributed database. The database will
		901	be mirrored asynchronously on all global nodes. Other nodes bind to one
		902	of the global nodes for their needs. Every node has a "local database"
		903	which contains all the values that are set locally. All local databases
		904	are merged together to form the global database, which can be queried.
		905
		906	The database structure is that of a two-level hash - the database hash
		907	contains hashes which contain values, similarly to a perl hash of hashes,
		908	i.e.:
		909
		910	$DATABASE{$family}{$subkey} = $value
		911
		912	The top level hash key is called "family", and the second-level hash key
		913	is called "subkey" or simply "key".
		914
		915	The family must be alphanumeric, i.e. start with a letter and consist
		916	of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
		917	pretty much like Perl module names.
		918
		919	As the family namespace is global, it is recommended to prefix family names
		920	with the name of the application or module using it.
		921
		922	The subkeys must be non-empty strings, with no further restrictions.
		923
		924	The values should preferably be strings, but other perl scalars should
		925	work as well (such as C<undef>, arrays and hashes).
		926
		927	Every database entry is owned by one node - adding the same family/subkey
		928	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
		929	but the result might be nondeterministic, i.e. the key might have
		930	different values on different nodes.
		931
		932	Different subkeys in the same family can be owned by different nodes
		933	without problems, and in fact, this is the common method to create worker
		934	pools. For example, a worker port for image scaling might do this:
		935
		936	db_set my_image_scalers => $port;
		937
		938	And clients looking for an image scaler will want to get the
		939	C<my_image_scalers> keys from time to time:
		940
		941	db_keys my_image_scalers => sub {
		942	@ports = @{ $_[0] };
		943	};
		944
		945	Or better yet, they want to monitor the database family, so they always
		946	have a reasonable up-to-date copy:
		947
		948	db_mon my_image_scalers => sub {
		949	@ports = keys %{ $_[0] };
		950	};
		951
		952	In general, you can set or delete single subkeys, but query and monitor
		953	whole families only.
		954
		955	If you feel the need to monitor or query a single subkey, try giving it
		956	it's own family.
		957
		958	=over
		959
		960	=item $guard = db_set $family => $subkey [=> $value]
		961
		962	Sets (or replaces) a key to the database - if C<$value> is omitted,
		963	C<undef> is used instead.
		964
		965	When called in non-void context, C<db_set> returns a guard that
		966	automatically calls C<db_del> when it is destroyed.
		967
		968	=item db_del $family => $subkey...
		969
		970	Deletes one or more subkeys from the database family.
		971
		972	=item $guard = db_reg $family => $port => $value
		973
		974	=item $guard = db_reg $family => $port
		975
		976	=item $guard = db_reg $family
		977
		978	Registers a port in the given family and optionally returns a guard to
		979	remove it.
		980
		981	This function basically does the same as:
		982
		983	db_set $family => $port => $value
		984
		985	Except that the port is monitored and automatically removed from the
		986	database family when it is kil'ed.
		987
		988	If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
		989	C<$SELF> is used.
		990
		991	This function is most useful to register a port in some port group (which
		992	is just another name for a database family), and have it removed when the
		993	port is gone. This works best when the port is a local port.
		994
		995	=cut
		996
		997	sub db_reg($$;$) {
		998	my $family = shift;
		999	my $port = @_ ? shift : $SELF;
		1000
		1001	my $clr = sub { db_del $family => $port };
		1002	mon $port, $clr;
		1003
		1004	db_set $family => $port => $_[0];
		1005
		1006	defined wantarray
		1007	and &Guard::guard ($clr)
		1008	}
		1009
		1010	=item db_family $family => $cb->(\%familyhash)
		1011
		1012	Queries the named database C<$family> and call the callback with the
		1013	family represented as a hash. You can keep and freely modify the hash.
		1014
		1015	=item db_keys $family => $cb->(\@keys)
		1016
		1017	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		1018	them as array reference to the callback.
		1019
		1020	=item db_values $family => $cb->(\@values)
		1021
		1022	Same as C<db_family>, except it only queries the family I<values> and passes them
		1023	as array reference to the callback.
		1024
		1025	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		1026
		1027	Creates a monitor on the given database family. Each time a key is set
		1028	or or is deleted the callback is called with a hash containing the
		1029	database family and three lists of added, changed and deleted subkeys,
		1030	respectively. If no keys have changed then the array reference might be
		1031	C<undef> or even missing.
		1032
		1033	If not called in void context, a guard object is returned that, when
		1034	destroyed, stops the monitor.
		1035
		1036	The family hash reference and the key arrays belong to AnyEvent::MP and
		1037	B<must not be modified or stored> by the callback. When in doubt, make a
		1038	copy.
		1039
		1040	As soon as possible after the monitoring starts, the callback will be
		1041	called with the intiial contents of the family, even if it is empty,
		1042	i.e. there will always be a timely call to the callback with the current
		1043	contents.
		1044
		1045	It is possible that the callback is called with a change event even though
		1046	the subkey is already present and the value has not changed.
		1047
		1048	The monitoring stops when the guard object is destroyed.
		1049
		1050	Example: on every change to the family "mygroup", print out all keys.
		1051
		1052	my $guard = db_mon mygroup => sub {
		1053	my ($family, $a, $c, $d) = @_;
		1054	print "mygroup members: ", (join " ", keys %$family), "\n";
		1055	};
		1056
		1057	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1058
		1059	my $guard; $guard = db_mon My::Module::workers => sub {
		1060	my ($family, $a, $c, $d) = @_;
		1061	return unless %$family;
		1062	undef $guard;
		1063	print "My::Module::workers now nonempty\n";
		1064	};
		1065
		1066	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1067
		1068	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1069	my ($family, $a, $c, $d) = @_;
		1070
		1071	print "+$_=$family->{$_}\n" for @$a;
		1072	print "*$_=$family->{$_}\n" for @$c;
		1073	print "-$_=$family->{$_}\n" for @$d;
		1074	};
		1075
		1076	=cut
		1077
720	=back	1078	=back
721		1079
722	=head1 AnyEvent::MP vs. Distributed Erlang	1080	=head1 AnyEvent::MP vs. Distributed Erlang
723		1081
724	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1082	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
725	== aemp node, Erlang process == aemp port), so many of the documents and	1083	== aemp node, Erlang process == aemp port), so many of the documents and
726	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	1084	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
727	sample:	1085	sample:
728		1086
729	http://www.Erlang.se/doc/programming_rules.shtml	1087	http://www.erlang.se/doc/programming_rules.shtml
730	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	1088	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
731	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6	1089	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
732	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	1090	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
733		1091
734	Despite the similarities, there are also some important differences:	1092	Despite the similarities, there are also some important differences:
735		1093
736	=over 4	1094	=over 4
737		1095
738	=item * Node IDs are arbitrary strings in AEMP.	1096	=item * Node IDs are arbitrary strings in AEMP.
739		1097
740	Erlang relies on special naming and DNS to work everywhere in the same	1098	Erlang relies on special naming and DNS to work everywhere in the same
741	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by	1099	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
742	configuration or DNS), but will otherwise discover other odes itself.	1100	configuration or DNS), and possibly the addresses of some seed nodes, but
		1101	will otherwise discover other nodes (and their IDs) itself.
743		1102
744	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	1103	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
745	uses "local ports are like remote ports".	1104	uses "local ports are like remote ports".
746		1105
747	The failure modes for local ports are quite different (runtime errors	1106	The failure modes for local ports are quite different (runtime errors
…		…
756	ports being the special case/exception, where transport errors cannot	1115	ports being the special case/exception, where transport errors cannot
757	occur.	1116	occur.
758		1117
759	=item * Erlang uses processes and a mailbox, AEMP does not queue.	1118	=item * Erlang uses processes and a mailbox, AEMP does not queue.
760		1119
761	Erlang uses processes that selectively receive messages, and therefore	1120	Erlang uses processes that selectively receive messages out of order, and
762	needs a queue. AEMP is event based, queuing messages would serve no	1121	therefore needs a queue. AEMP is event based, queuing messages would serve
763	useful purpose. For the same reason the pattern-matching abilities of	1122	no useful purpose. For the same reason the pattern-matching abilities
764	AnyEvent::MP are more limited, as there is little need to be able to	1123	of AnyEvent::MP are more limited, as there is little need to be able to
765	filter messages without dequeuing them.	1124	filter messages without dequeuing them.
766		1125
767	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	1126	This is not a philosophical difference, but simply stems from AnyEvent::MP
		1127	being event-based, while Erlang is process-based.
		1128
		1129	You cna have a look at L<Coro::MP> for a more Erlang-like process model on
		1130	top of AEMP and Coro threads.
768		1131
769	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	1132	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
770		1133
771	Sending messages in Erlang is synchronous and blocks the process (and	1134	Sending messages in Erlang is synchronous and blocks the process until
		1135	a conenction has been established and the message sent (and so does not
772	so does not need a queue that can overflow). AEMP sends are immediate,	1136	need a queue that can overflow). AEMP sends return immediately, connection
773	connection establishment is handled in the background.	1137	establishment is handled in the background.
774		1138
775	=item * Erlang suffers from silent message loss, AEMP does not.	1139	=item * Erlang suffers from silent message loss, AEMP does not.
776		1140
777	Erlang makes few guarantees on messages delivery - messages can get lost	1141	Erlang implements few guarantees on messages delivery - messages can get
778	without any of the processes realising it (i.e. you send messages a, b,	1142	lost without any of the processes realising it (i.e. you send messages a,
779	and c, and the other side only receives messages a and c).	1143	b, and c, and the other side only receives messages a and c).
780		1144
781	AEMP guarantees correct ordering, and the guarantee that after one message	1145	AEMP guarantees (modulo hardware errors) correct ordering, and the
782	is lost, all following ones sent to the same port are lost as well, until	1146	guarantee that after one message is lost, all following ones sent to the
783	monitoring raises an error, so there are no silent "holes" in the message	1147	same port are lost as well, until monitoring raises an error, so there are
784	sequence.	1148	no silent "holes" in the message sequence.
		1149
		1150	If you want your software to be very reliable, you have to cope with
		1151	corrupted and even out-of-order messages in both Erlang and AEMP. AEMP
		1152	simply tries to work better in common error cases, such as when a network
		1153	link goes down.
785		1154
786	=item * Erlang can send messages to the wrong port, AEMP does not.	1155	=item * Erlang can send messages to the wrong port, AEMP does not.
787		1156
788	In Erlang it is quite likely that a node that restarts reuses a process ID	1157	In Erlang it is quite likely that a node that restarts reuses an Erlang
789	known to other nodes for a completely different process, causing messages	1158	process ID known to other nodes for a completely different process,
790	destined for that process to end up in an unrelated process.	1159	causing messages destined for that process to end up in an unrelated
		1160	process.
791		1161
792	AEMP never reuses port IDs, so old messages or old port IDs floating	1162	AEMP does not reuse port IDs, so old messages or old port IDs floating
793	around in the network will not be sent to an unrelated port.	1163	around in the network will not be sent to an unrelated port.
794		1164
795	=item * Erlang uses unprotected connections, AEMP uses secure	1165	=item * Erlang uses unprotected connections, AEMP uses secure
796	authentication and can use TLS.	1166	authentication and can use TLS.
797		1167
…		…
800		1170
801	=item * The AEMP protocol is optimised for both text-based and binary	1171	=item * The AEMP protocol is optimised for both text-based and binary
802	communications.	1172	communications.
803		1173
804	The AEMP protocol, unlike the Erlang protocol, supports both programming	1174	The AEMP protocol, unlike the Erlang protocol, supports both programming
805	language independent text-only protocols (good for debugging) and binary,	1175	language independent text-only protocols (good for debugging), and binary,
806	language-specific serialisers (e.g. Storable). By default, unless TLS is	1176	language-specific serialisers (e.g. Storable). By default, unless TLS is
807	used, the protocol is actually completely text-based.	1177	used, the protocol is actually completely text-based.
808		1178
809	It has also been carefully designed to be implementable in other languages	1179	It has also been carefully designed to be implementable in other languages
810	with a minimum of work while gracefully degrading functionality to make the	1180	with a minimum of work while gracefully degrading functionality to make the
811	protocol simple.	1181	protocol simple.
812		1182
813	=item * AEMP has more flexible monitoring options than Erlang.	1183	=item * AEMP has more flexible monitoring options than Erlang.
814		1184
815	In Erlang, you can chose to receive I<all> exit signals as messages	1185	In Erlang, you can chose to receive I<all> exit signals as messages or
816	or I<none>, there is no in-between, so monitoring single processes is	1186	I<none>, there is no in-between, so monitoring single Erlang processes is
817	difficult to implement. Monitoring in AEMP is more flexible than in	1187	difficult to implement.
818	Erlang, as one can choose between automatic kill, exit message or callback	1188
819	on a per-process basis.	1189	Monitoring in AEMP is more flexible than in Erlang, as one can choose
		1190	between automatic kill, exit message or callback on a per-port basis.
820		1191
821	=item * Erlang tries to hide remote/local connections, AEMP does not.	1192	=item * Erlang tries to hide remote/local connections, AEMP does not.
822		1193
823	Monitoring in Erlang is not an indicator of process death/crashes, in the	1194	Monitoring in Erlang is not an indicator of process death/crashes, in the
824	same way as linking is (except linking is unreliable in Erlang).	1195	same way as linking is (except linking is unreliable in Erlang).
…		…
846	overhead, as well as having to keep a proxy object everywhere.	1217	overhead, as well as having to keep a proxy object everywhere.
847		1218
848	Strings can easily be printed, easily serialised etc. and need no special	1219	Strings can easily be printed, easily serialised etc. and need no special
849	procedures to be "valid".	1220	procedures to be "valid".
850		1221
851	And as a result, a miniport consists of a single closure stored in a	1222	And as a result, a port with just a default receiver consists of a single
852	global hash - it can't become much cheaper.	1223	code reference stored in a global hash - it can't become much cheaper.
853		1224
854	=item Why favour JSON, why not a real serialising format such as Storable?	1225	=item Why favour JSON, why not a real serialising format such as Storable?
855		1226
856	In fact, any AnyEvent::MP node will happily accept Storable as framing	1227	In fact, any AnyEvent::MP node will happily accept Storable as framing
857	format, but currently there is no way to make a node use Storable by	1228	format, but currently there is no way to make a node use Storable by
…		…
867	Keeping your messages simple, concentrating on data structures rather than	1238	Keeping your messages simple, concentrating on data structures rather than
868	objects, will keep your messages clean, tidy and efficient.	1239	objects, will keep your messages clean, tidy and efficient.
869		1240
870	=back	1241	=back
871		1242
		1243	=head1 PORTING FROM AnyEvent::MP VERSION 1.X
		1244
		1245	AEMP version 2 has a few major incompatible changes compared to version 1:
		1246
		1247	=over 4
		1248
		1249	=item AnyEvent::MP::Global no longer has group management functions.
		1250
		1251	At least not officially - the grp_* functions are still exported and might
		1252	work, but they will be removed in some later release.
		1253
		1254	AnyEvent::MP now comes with a distributed database that is more
		1255	powerful. Its database families map closely to port groups, but the API
		1256	has changed (the functions are also now exported by AnyEvent::MP). Here is
		1257	a rough porting guide:
		1258
		1259	grp_reg $group, $port # old
		1260	db_reg $group, $port # new
		1261
		1262	$list = grp_get $group # old
		1263	db_keys $group, sub { my $list = shift } # new
		1264
		1265	grp_mon $group, $cb->(\@ports, $add, $del) # old
		1266	db_mon $group, $cb->(\%ports, $add, $change, $del) # new
		1267
		1268	C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is
		1269	no longer instant, because the local node might not have a copy of the
		1270	group. You can either modify your code to allow for a callback, or use
		1271	C<db_mon> to keep an updated copy of the group:
		1272
		1273	my $local_group_copy;
		1274	db_mon $group => sub { $local_group_copy = $_[0] };
		1275
		1276	# now "keys %$local_group_copy" always returns the most up-to-date
		1277	# list of ports in the group.
		1278
		1279	C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
		1280	passes a hash as first argument, and an extra C<$chg> argument that can be
		1281	ignored:
		1282
		1283	db_mon $group => sub {
		1284	my ($ports, $add, $chg, $lde) = @_;
		1285	$ports = [keys %$ports];
		1286
		1287	# now $ports, $add and $del are the same as
		1288	# were originally passed by grp_mon.
		1289	...
		1290	};
		1291
		1292	=item Nodes not longer connect to all other nodes.
		1293
		1294	In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
		1295	module, which in turn would create connections to all other nodes in the
		1296	network (helped by the seed nodes).
		1297
		1298	In version 2.x, global nodes still connect to all other global nodes, but
		1299	other nodes don't - now every node either is a global node itself, or
		1300	attaches itself to another global node.
		1301
		1302	If a node isn't a global node itself, then it attaches itself to one
		1303	of its seed nodes. If that seed node isn't a global node yet, it will
		1304	automatically be upgraded to a global node.
		1305
		1306	So in many cases, nothing needs to be changed - one just has to make sure
		1307	that all seed nodes are meshed together with the other seed nodes (as with
		1308	AEMP 1.x), and other nodes specify them as seed nodes. This is most easily
		1309	achieved by specifying the same set of seed nodes for all nodes in the
		1310	network.
		1311
		1312	Not opening a connection to every other node is usually an advantage,
		1313	except when you need the lower latency of an already established
		1314	connection. To ensure a node establishes a connection to another node,
		1315	you can monitor the node port (C<mon $node, ...>), which will attempt to
		1316	create the connection (and notify you when the connection fails).
		1317
		1318	=item Listener-less nodes (nodes without binds) are gone.
		1319
		1320	And are not coming back, at least not in their old form. If no C<binds>
		1321	are specified for a node, AnyEvent::MP assumes a default of C<:>.
		1322
		1323	There are vague plans to implement some form of routing domains, which
		1324	might or might not bring back listener-less nodes, but don't count on it.
		1325
		1326	The fact that most connections are now optional somewhat mitigates this,
		1327	as a node can be effectively unreachable from the outside without any
		1328	problems, as long as it isn't a global node and only reaches out to other
		1329	nodes (as opposed to being contacted from other nodes).
		1330
		1331	=item $AnyEvent::MP::Kernel::WARN has gone.
		1332
		1333	AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
		1334	uses this, and so should your programs.
		1335
		1336	Every module now documents what kinds of messages it generates, with
		1337	AnyEvent::MP acting as a catch all.
		1338
		1339	On the positive side, this means that instead of setting
		1340	C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> -
		1341	much less to type.
		1342
		1343	=back
		1344
		1345	=head1 LOGGING
		1346
		1347	AnyEvent::MP does not normally log anything by itself, but sinc eit is the
		1348	root of the contetx hierarchy for AnyEvent::MP modules, it will receive
		1349	all log messages by submodules.
		1350
872	=head1 SEE ALSO	1351	=head1 SEE ALSO
873		1352
874	L<AnyEvent::MP::Intro> - a gentle introduction.	1353	L<AnyEvent::MP::Intro> - a gentle introduction.
875		1354
876	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1355	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
877		1356
878	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	1357	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
879	your applications.	1358	your applications.
		1359
		1360	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
880		1361
881	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from	1362	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
882	all nodes.	1363	all nodes.
883		1364
884	L<AnyEvent>.	1365	L<AnyEvent>.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.85 by root, Tue Sep 8 01:54:13 2009 UTC vs. Revision 1.142 by root, Fri Mar 23 13:44:01 2012 UTC

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Revision 1.85 by root, Tue Sep 8 01:54:13 2009 UTC vs.
Revision 1.142 by root, Fri Mar 23 13:44:01 2012 UTC