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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC vs.
Revision 1.115 by root, Fri May 7 18:14:21 2010 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent::MP - multi-processing/message-passing framework	3	AnyEvent::MP - erlang-style multi-processing/message-passing framework
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
15	# initialise the node so it can send/receive messages	14	# initialise the node so it can send/receive messages
16	initialise_node;	15	configure;
17		16
18	# ports are message endpoints	17	# ports are message destinations
19		18
20	# sending messages	19	# sending messages
21	snd $port, type => data...;	20	snd $port, type => data...;
22	snd $port, @msg;	21	snd $port, @msg;
23	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
24		23
25	# creating/using ports, the simple way	24	# creating/using ports, the simple way
26	my $simple_port = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
27		26
28	# creating/using ports, tagged message matching	27	# creating/using ports, tagged message matching
29	my $port = port;	28	my $port = port;
30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
31	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
32		31
33	# create a port on another node	32	# create a port on another node
34	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
35		34
		35	# destroy a prot again
		36	kil $port; # "normal" kill
		37	kil $port, my_error => "everything is broken"; # error kill
		38
36	# monitoring	39	# monitoring
37	mon $port, $cb->(@msg) # callback is invoked on death	40	mon $localport, $cb->(@msg) # callback is invoked on death
38	mon $port, $otherport # kill otherport on abnormal death	41	mon $localport, $otherport # kill otherport on abnormal death
39	mon $port, $otherport, @msg # send message on death	42	mon $localport, $otherport, @msg # send message on death
		43
		44	# temporarily execute code in port context
		45	peval $port, sub { die "kill the port!" };
		46
		47	# execute callbacks in $SELF port context
		48	my $timer = AE::timer 1, 0, psub {
		49	die "kill the port, delayed";
		50	};
40		51
41	=head1 CURRENT STATUS	52	=head1 CURRENT STATUS
42		53
		54	bin/aemp - stable.
43	AnyEvent::MP - stable API, should work	55	AnyEvent::MP - stable API, should work.
44	AnyEvent::MP::Intro - outdated	56	AnyEvent::MP::Intro - explains most concepts.
45	AnyEvent::MP::Kernel - mostly stable	57	AnyEvent::MP::Kernel - mostly stable API.
46	AnyEvent::MP::Global - mostly stable	58	AnyEvent::MP::Global - stable API.
47	AnyEvent::MP::Node - mostly stable, but internal anyways
48	AnyEvent::MP::Transport - mostly stable, but internal anyways
49
50	stay tuned.
51		59
52	=head1 DESCRIPTION	60	=head1 DESCRIPTION
53		61
54	This module (-family) implements a simple message passing framework.	62	This module (-family) implements a simple message passing framework.
55		63
57	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.
58		66
59	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>
60	manual page and the examples under F<eg/>.	68	manual page and the examples under F<eg/>.
61		69
62	At the moment, this module family is a bit underdocumented.
63
64	=head1 CONCEPTS	70	=head1 CONCEPTS
65		71
66	=over 4	72	=over 4
67		73
68	=item port	74	=item port
69		75
70	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).
71		78
72	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
73	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
74	anything was listening for them or not.	81	anything was listening for them or not.
75		82
…		…
86		93
87	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
88	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
89	currently.	96	currently.
90		97
91	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
92		99
93	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
94	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
95	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
96	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
100	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
101	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
102	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
103	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
104		111
105	=item seeds - C<host:port>	112	=item seed nodes
106		113
107	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
108	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
109	network. This node is called a seed.	116	network. This node is called a seed.
110		117
111	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
112	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
113	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
114	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.
115	join the network.
116		129
117	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
118	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.
119		139
120	=back	140	=back
121		141
122	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
123		143
…		…
135		155
136	use AE ();	156	use AE ();
137		157
138	use base "Exporter";	158	use base "Exporter";
139		159
140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.29;
141		161
142	our @EXPORT = qw(	162	our @EXPORT = qw(
143	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
144	initialise_node	164	configure
145	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
146	port	166	port
147	);	167	);
148		168
149	our $SELF;	169	our $SELF;
150		170
…		…
156		176
157	=item $thisnode = NODE / $NODE	177	=item $thisnode = NODE / $NODE
158		178
159	The C<NODE> function returns, and the C<$NODE> variable contains, the node	179	The C<NODE> function returns, and the C<$NODE> variable contains, the node
160	ID of the node running in the current process. This value is initialised by	180	ID of the node running in the current process. This value is initialised by
161	a call to C<initialise_node>.	181	a call to C<configure>.
162		182
163	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
164		184
165	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.
166		186
167	=item initialise_node $profile_name, key => value...	187	=item configure $profile, key => value...
		188
		189	=item configure key => value...
168		190
169	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
170	"distributed mode") it has to initialise itself - the minimum a node needs	192	"distributed mode") it has to configure itself - the minimum a node needs
171	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
172	some other nodes in the network to discover other nodes.	194	some other nodes in the network to discover other nodes.
173		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
174	This function initialises a node - it must be called exactly once (or	199	This function configures a node - it must be called exactly once (or
175	never) before calling other AnyEvent::MP functions.	200	never) before calling other AnyEvent::MP functions.
176		201
177	The first argument is a profile name. If it is C<undef> or missing, then	202	=over 4
178	the current nodename will be used instead (i.e. F<uname -n>).
179		203
		204	=item step 1, gathering configuration from profiles
		205
180	The function first looks up the profile in the aemp configuration (see the	206	The function first looks up a profile in the aemp configuration (see the
181	L<aemp> commandline utility). the profile is calculated as follows:	207	L<aemp> commandline utility). The profile name can be specified via the
		208	named C<profile> parameter or can simply be the first parameter). If it is
		209	missing, then the nodename (F<uname -n>) will be used as profile name.
182		210
		211	The profile data is then gathered as follows:
		212
183	First, all remaining key => value pairs (all of which are conviniently	213	First, all remaining key => value pairs (all of which are conveniently
184	undocumented at the moment) will be used. Then they will be overwritten by	214	undocumented at the moment) will be interpreted as configuration
185	any values specified in the global default configuration (see the F<aemp>	215	data. Then they will be overwritten by any values specified in the global
186	utility), then the chain of profiles selected, if any. That means that	216	default configuration (see the F<aemp> utility), then the chain of
		217	profiles chosen by the profile name (and any C<parent> attributes).
		218
187	the values specified in the profile have highest priority and the values	219	That means that the values specified in the profile have highest priority
188	specified via C<initialise_node> have lowest priority.	220	and the values specified directly via C<configure> have lowest priority,
		221	and can only be used to specify defaults.
189		222
190	If the profile specifies a node ID, then this will become the node ID of	223	If the profile specifies a node ID, then this will become the node ID of
191	this process. If not, then the profile name will be used as node ID. The	224	this process. If not, then the profile name will be used as node ID. The
192	special node ID of C<anon/> will be replaced by a random node ID.	225	special node ID of C<anon/> will be replaced by a random node ID.
		226
		227	=item step 2, bind listener sockets
193		228
194	The next step is to look up the binds in the profile, followed by binding	229	The next step is to look up the binds in the profile, followed by binding
195	aemp protocol listeners on all binds specified (it is possible and valid	230	aemp protocol listeners on all binds specified (it is possible and valid
196	to have no binds, meaning that the node cannot be contacted form the	231	to have no binds, meaning that the node cannot be contacted form the
197	outside. This means the node cannot talk to other nodes that also have no	232	outside. This means the node cannot talk to other nodes that also have no
198	binds, but it can still talk to all "normal" nodes).	233	binds, but it can still talk to all "normal" nodes).
199		234
200	If the profile does not specify a binds list, then a default of C<*> is	235	If the profile does not specify a binds list, then a default of C<*> is
201	used.	236	used, meaning the node will bind on a dynamically-assigned port on every
		237	local IP address it finds.
202		238
		239	=item step 3, connect to seed nodes
		240
203	Lastly, the seeds list from the profile is passed to the	241	As the last step, the seeds list from the profile is passed to the
204	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
205	connectivity with at least on of those seed nodes at any point in time.	243	connectivity with at least one node at any point in time.
206		244
207	Example: become a distributed node listening on the guessed noderef, or	245	=back
208	the one specified via C<aemp> for the current node. This should be the	246
		247	Example: become a distributed node using the local node name as profile.
209	most common form of invocation for "daemon"-type nodes.	248	This should be the most common form of invocation for "daemon"-type nodes.
210		249
211	initialise_node;	250	configure
212		251
213	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
214	clients.	253	clients.
215		254
216	initialise_node "anon/";	255	configure nodeid => "anon/";
217		256
218	Example: become a distributed node. If there is no profile of the given	257	Example: configure a node using a profile called seed, which si suitable
219	name, or no binds list was specified, resolve C<localhost:4044> and bind	258	for a seed node as it binds on all local addresses on a fixed port (4040,
220	on the resulting addresses.	259	customary for aemp).
221		260
222	initialise_node "localhost:4044";	261	# use the aemp commandline utility
		262	# aemp profile seed nodeid anon/ binds '*:4040'
		263
		264	# then use it
		265	configure profile => "seed";
		266
		267	# or simply use aemp from the shell again:
		268	# aemp run profile seed
		269
		270	# or provide a nicer-to-remember nodeid
		271	# aemp run profile seed nodeid "$(hostname)"
223		272
224	=item $SELF	273	=item $SELF
225		274
226	Contains the current port id while executing C<rcv> callbacks or C<psub>	275	Contains the current port id while executing C<rcv> callbacks or C<psub>
227	blocks.	276	blocks.
…		…
337	msg1 => sub { ... },	386	msg1 => sub { ... },
338	...	387	...
339	;	388	;
340		389
341	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
342	(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.
343		392
344	rcv $port, $otherport => sub {	393	rcv $port, $otherport => sub {
345	my @reply = @_;	394	my @reply = @_;
346		395
347	rcv $SELF, $otherport;	396	rcv $SELF, $otherport;
…		…
349		398
350	=cut	399	=cut
351		400
352	sub rcv($@) {	401	sub rcv($@) {
353	my $port = shift;	402	my $port = shift;
354	my ($noderef, $portid) = split /#/, $port, 2;	403	my ($nodeid, $portid) = split /#/, $port, 2;
355		404
356	$NODE{$noderef} == $NODE{""}	405	$NODE{$nodeid} == $NODE{""}
357	or Carp::croak "$port: rcv can only be called on local ports, caught";	406	or Carp::croak "$port: rcv can only be called on local ports, caught";
358		407
359	while (@_) {	408	while (@_) {
360	if (ref $_[0]) {	409	if (ref $_[0]) {
361	if (my $self = $PORT_DATA{$portid}) {	410	if (my $self = $PORT_DATA{$portid}) {
362	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
363	or Carp::croak "$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";
364		413
365	$self->[2] = shift;	414	$self->[0] = shift;
366	} else {	415	} else {
367	my $cb = shift;	416	my $cb = shift;
368	$PORT{$portid} = sub {	417	$PORT{$portid} = sub {
369	local $SELF = $port;	418	local $SELF = $port;
370	eval { &$cb }; _self_die if $@;	419	eval { &$cb }; _self_die if $@;
371	};	420	};
372	}	421	}
373	} elsif (defined $_[0]) {	422	} elsif (defined $_[0]) {
374	my $self = $PORT_DATA{$portid} \|\|= do {	423	my $self = $PORT_DATA{$portid} \|\|= do {
375	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	424	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
376		425
377	$PORT{$portid} = sub {	426	$PORT{$portid} = sub {
378	local $SELF = $port;	427	local $SELF = $port;
379		428
380	if (my $cb = $self->[1]{$_[0]}) {	429	if (my $cb = $self->[1]{$_[0]}) {
…		…
402	}	451	}
403		452
404	$port	453	$port
405	}	454	}
406		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
407	=item $closure = psub { BLOCK }	493	=item $closure = psub { BLOCK }
408		494
409	Remembers C<$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
410	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>
411	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 $SELF, sub {
		500	BLOCK }, @_ } >>.
412		501
413	This is useful when you register callbacks from C<rcv> callbacks:	502	This is useful when you register callbacks from C<rcv> callbacks:
414		503
415	rcv delayed_reply => sub {	504	rcv delayed_reply => sub {
416	my ($delay, @reply) = @_;	505	my ($delay, @reply) = @_;
…		…
452		541
453	Monitor the given port and do something when the port is killed or	542	Monitor the given port and do something when the port is killed or
454	messages to it were lost, and optionally return a guard that can be used	543	messages to it were lost, and optionally return a guard that can be used
455	to stop monitoring again.	544	to stop monitoring again.
456		545
		546	In the first form (callback), the callback is simply called with any
		547	number of C<@reason> elements (no @reason means that the port was deleted
		548	"normally"). Note also that I<< the callback B<must> never die >>, so use
		549	C<eval> if unsure.
		550
		551	In the second form (another port given), the other port (C<$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
457	C<mon> effectively guarantees that, in the absence of hardware failures,	572	C<mon> effectively guarantees that, in the absence of hardware failures,
458	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
459	arrive, or the monitoring action will be invoked after possible message	574	arrive, or the monitoring action will be invoked after possible message
460	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
461	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
462	port). After the monitoring action was invoked, further messages might get	577	port). After the monitoring action was invoked, further messages might get
463	delivered again.	578	delivered again.
464		579
465	Note that monitoring-actions are one-shot: once messages are lost (and a	580	Inter-host-connection timeouts and monitoring depend on the transport
466	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).
467		584
468	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
469	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
470	"normally"). Note also that I<< the callback B<must> never die >>, so use	587	to ensure some maximum latency.
471	C<eval> if unsure.
472
473	In the second form (another port given), the other port (C<$rcvport>)
474	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
475	"normal" kils nothing happens, while under all other conditions, the other
476	port is killed with the same reason.
477
478	The third form (kill self) is the same as the second form, except that
479	C<$rvport> defaults to C<$SELF>.
480
481	In the last form (message), a message of the form C<@msg, @reason> will be
482	C<snd>.
483
484	As a rule of thumb, monitoring requests should always monitor a port from
485	a local port (or callback). The reason is that kill messages might get
486	lost, just like any other message. Another less obvious reason is that
487	even monitoring requests can get lost (for exmaple, when the connection
488	to the other node goes down permanently). When monitoring a port locally
489	these problems do not exist.
490		588
491	Example: call a given callback when C<$port> is killed.	589	Example: call a given callback when C<$port> is killed.
492		590
493	mon $port, sub { warn "port died because of <@_>\n" };	591	mon $port, sub { warn "port died because of <@_>\n" };
494		592
…		…
501	mon $port, $self => "restart";	599	mon $port, $self => "restart";
502		600
503	=cut	601	=cut
504		602
505	sub mon {	603	sub mon {
506	my ($noderef, $port) = split /#/, shift, 2;	604	my ($nodeid, $port) = split /#/, shift, 2;
507		605
508	my $node = $NODE{$noderef} \|\| add_node $noderef;	606	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
509		607
510	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	608	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
511		609
512	unless (ref $cb) {	610	unless (ref $cb) {
513	if (@_) {	611	if (@_) {
…		…
522	}	620	}
523		621
524	$node->monitor ($port, $cb);	622	$node->monitor ($port, $cb);
525		623
526	defined wantarray	624	defined wantarray
527	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	625	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
528	}	626	}
529		627
530	=item $guard = mon_guard $port, $ref, $ref...	628	=item $guard = mon_guard $port, $ref, $ref...
531		629
532	Monitors the given C<$port> and keeps the passed references. When the port	630	Monitors the given C<$port> and keeps the passed references. When the port
…		…
555		653
556	=item kil $port[, @reason]	654	=item kil $port[, @reason]
557		655
558	Kill the specified port with the given C<@reason>.	656	Kill the specified port with the given C<@reason>.
559		657
560	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" -
561	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
562	"normally").	660	(C<mon $mport, $lport> form) to get killed.
563		661
564	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>
565	C<mon>, see above).	663	form) get killed with the same reason.
566		664
567	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
568	will be reported as reason C<< die => $@ >>.	666	will be reported as reason C<< die => $@ >>.
569		667
570	Transport/communication errors are reported as C<< transport_error =>	668	Transport/communication errors are reported as C<< transport_error =>
…		…
589	the package, then the package above the package and so on (e.g.	687	the package, then the package above the package and so on (e.g.
590	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	688	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
591	exists or it runs out of package names.	689	exists or it runs out of package names.
592		690
593	The init function is then called with the newly-created port as context	691	The init function is then called with the newly-created port as context
594	object (C<$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.
595		695
596	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
597	port, and in the remote init function, immediately monitor the passed	697	port, and in the remote init function, immediately monitor the passed
598	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
599	when there is a problem.	699	when there is a problem.
600		700
		701	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		702	caller before C<spawn> returns (by delaying invocation when spawn is
		703	called for the local node).
		704
601	Example: spawn a chat server port on C<$othernode>.	705	Example: spawn a chat server port on C<$othernode>.
602		706
603	# this node, executed from within a port context:	707	# this node, executed from within a port context:
604	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	708	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
605	mon $server;	709	mon $server;
…		…
619		723
620	sub _spawn {	724	sub _spawn {
621	my $port = shift;	725	my $port = shift;
622	my $init = shift;	726	my $init = shift;
623		727
		728	# rcv will create the actual port
624	local $SELF = "$NODE#$port";	729	local $SELF = "$NODE#$port";
625	eval {	730	eval {
626	&{ load_func $init }	731	&{ load_func $init }
627	};	732	};
628	_self_die if $@;	733	_self_die if $@;
629	}	734	}
630		735
631	sub spawn(@) {	736	sub spawn(@) {
632	my ($noderef, undef) = split /#/, shift, 2;	737	my ($nodeid, undef) = split /#/, shift, 2;
633		738
634	my $id = "$RUNIQ." . $ID++;	739	my $id = "$RUNIQ." . $ID++;
635		740
636	$_[0] =~ /::/	741	$_[0] =~ /::/
637	or Carp::croak "spawn init function must be a fully-qualified name, caught";	742	or Carp::croak "spawn init function must be a fully-qualified name, caught";
638		743
639	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;	744	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
640		745
641	"$noderef#$id"	746	"$nodeid#$id"
642	}	747	}
643		748
644	=item after $timeout, @msg	749	=item after $timeout, @msg
645		750
646	=item after $timeout, $callback	751	=item after $timeout, $callback
…		…
663	? $action[0]()	768	? $action[0]()
664	: snd @action;	769	: snd @action;
665	};	770	};
666	}	771	}
667		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
668	=back	825	=back
669		826
670	=head1 AnyEvent::MP vs. Distributed Erlang	827	=head1 AnyEvent::MP vs. Distributed Erlang
671		828
672	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
673	== 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
674	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
675	sample:	832	sample:
676		833
677	http://www.Erlang.se/doc/programming_rules.shtml	834	http://www.erlang.se/doc/programming_rules.shtml
678	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
679	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
680	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
681		838
682	Despite the similarities, there are also some important differences:	839	Despite the similarities, there are also some important differences:
683		840
684	=over 4	841	=over 4
685		842
686	=item * Node IDs are arbitrary strings in AEMP.	843	=item * Node IDs are arbitrary strings in AEMP.
687		844
688	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
689	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
690	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.
691		849
692	=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
693	uses "local ports are like remote ports".	851	uses "local ports are like remote ports".
694		852
695	The failure modes for local ports are quite different (runtime errors	853	The failure modes for local ports are quite different (runtime errors
…		…
708		866
709	Erlang uses processes that selectively receive messages, and therefore	867	Erlang uses processes that selectively receive messages, and therefore
710	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
711	useful purpose. For the same reason the pattern-matching abilities of	869	useful purpose. For the same reason the pattern-matching abilities of
712	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
713	filter messages without dequeing them.	871	filter messages without dequeuing them.
714		872
715	(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).
716		874
717	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	875	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
718		876
…		…
720	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,
721	connection establishment is handled in the background.	879	connection establishment is handled in the background.
722		880
723	=item * Erlang suffers from silent message loss, AEMP does not.	881	=item * Erlang suffers from silent message loss, AEMP does not.
724		882
725	Erlang makes few guarantees on messages delivery - messages can get lost	883	Erlang implements few guarantees on messages delivery - messages can get
726	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,
727	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).
728		886
729	AEMP guarantees correct ordering, and the guarantee that after one message	887	AEMP guarantees correct ordering, and the guarantee that after one message
730	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
731	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
732	sequence.	890	sequence.
…		…
794	overhead, as well as having to keep a proxy object everywhere.	952	overhead, as well as having to keep a proxy object everywhere.
795		953
796	Strings can easily be printed, easily serialised etc. and need no special	954	Strings can easily be printed, easily serialised etc. and need no special
797	procedures to be "valid".	955	procedures to be "valid".
798		956
799	And as a result, a miniport consists of a single closure stored in a	957	And as a result, a port with just a default receiver consists of a single
800	global hash - it can't become much cheaper.	958	closure stored in a global hash - it can't become much cheaper.
801		959
802	=item Why favour JSON, why not a real serialising format such as Storable?	960	=item Why favour JSON, why not a real serialising format such as Storable?
803		961
804	In fact, any AnyEvent::MP node will happily accept Storable as framing	962	In fact, any AnyEvent::MP node will happily accept Storable as framing
805	format, but currently there is no way to make a node use Storable by	963	format, but currently there is no way to make a node use Storable by
…		…
821		979
822	L<AnyEvent::MP::Intro> - a gentle introduction.	980	L<AnyEvent::MP::Intro> - a gentle introduction.
823		981
824	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	982	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
825		983
826	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	984	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
827	your applications.	985	your applications.
		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.
828		991
829	L<AnyEvent>.	992	L<AnyEvent>.
830		993
831	=head1 AUTHOR	994	=head1 AUTHOR
832		995

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC vs. Revision 1.115 by root, Fri May 7 18:14:21 2010 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC vs.
Revision 1.115 by root, Fri May 7 18:14:21 2010 UTC