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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs.
Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC

…		…
30	This module (-family) implements a simple message passing framework.	30	This module (-family) implements a simple message passing framework.
31		31
32	Despite its simplicity, you can securely message other processes running	32	Despite its simplicity, you can securely message other processes running
33	on the same or other hosts.	33	on the same or other hosts.
34		34
		35	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		36	manual page.
		37
35	At the moment, this module family is severly brokena nd underdocumented,	38	At the moment, this module family is severly broken and underdocumented,
36	so do not use. This was uploaded mainly to reserve the CPAN namespace -	39	so do not use. This was uploaded mainly to reserve the CPAN namespace -
37	stay tuned!	40	stay tuned! The basic API should be finished, however.
38		41
39	=head1 CONCEPTS	42	=head1 CONCEPTS
40		43
41	=over 4	44	=over 4
42		45
43	=item port	46	=item port
44		47
45	A port is something you can send messages to with the C<snd> function, and	48	A port is something you can send messages to (with the C<snd> function).
46	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
47	messages they match, messages will not be queued.	50	Some ports allow you to register C<rcv> handlers that can match specific
		51	messages. All C<rcv> handlers will receive messages they match, messages
		52	will not be queued.
48		53
49	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
50		55
51	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	56	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
52	by a port name (a printable string of unspecified format).	57	separator, and a port name (a printable string of unspecified format). An
		58	exception is the the node port, whose ID is identical to its node
		59	reference.
53		60
54	=item node	61	=item node
55		62
56	A node is a single process containing at least one port - the node	63	A node is a single process containing at least one port - the node
57	port. You can send messages to node ports to let them create new ports,	64	port. You can send messages to node ports to find existing ports or to
58	among other things.	65	create new ports, among other things.
59		66
60	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
61	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
62	public" can you send them messages from unrelated other nodes.
63		69
64	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	70	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
65		71
66	A noderef is a string that either uniquely identifies a given node (for	72	A node reference is a string that either simply identifies the node (for
67	private and hidden nodes), or contains a recipe on how to reach a given	73	private and slave nodes), or contains a recipe on how to reach a given
68	node (for public nodes).	74	node (for public nodes).
69		75
		76	This recipe is simply a comma-separated list of C<address:port> pairs (for
		77	TCP/IP, other protocols might look different).
		78
		79	Node references come in two flavours: resolved (containing only numerical
		80	addresses) or unresolved (where hostnames are used instead of addresses).
		81
		82	Before using an unresolved node reference in a message you first have to
		83	resolve it.
		84
70	=back	85	=back
71		86
72	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
73		88
74	=over 4	89	=over 4
…		…
85		100
86	use AE ();	101	use AE ();
87		102
88	use base "Exporter";	103	use base "Exporter";
89		104
90	our $VERSION = '0.02';	105	our $VERSION = '0.1';
91	our @EXPORT = qw(	106	our @EXPORT = qw(
92	NODE $NODE *SELF node_of _any_	107	NODE $NODE *SELF node_of _any_
93	become_slave become_public	108	resolve_node initialise_node
94	snd rcv mon kil reg psub	109	snd rcv mon kil reg psub
95	port	110	port
96	);	111	);
97		112
98	our $SELF;	113	our $SELF;
…		…
112		127
113	=item $noderef = node_of $portid	128	=item $noderef = node_of $portid
114		129
115	Extracts and returns the noderef from a portid or a noderef.	130	Extracts and returns the noderef from a portid or a noderef.
116		131
		132	=item $cv = resolve_node $noderef
		133
		134	Takes an unresolved node reference that may contain hostnames and
		135	abbreviated IDs, resolves all of them and returns a resolved node
		136	reference.
		137
		138	In addition to C<address:port> pairs allowed in resolved noderefs, the
		139	following forms are supported:
		140
		141	=over 4
		142
		143	=item the empty string
		144
		145	An empty-string component gets resolved as if the default port (4040) was
		146	specified.
		147
		148	=item naked port numbers (e.g. C<1234>)
		149
		150	These are resolved by prepending the local nodename and a colon, to be
		151	further resolved.
		152
		153	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		154
		155	These are resolved by using AnyEvent::DNS to resolve them, optionally
		156	looking up SRV records for the C<aemp=4040> port, if no port was
		157	specified.
		158
		159	=back
		160
117	=item $SELF	161	=item $SELF
118		162
119	Contains the current port id while executing C<rcv> callbacks or C<psub>	163	Contains the current port id while executing C<rcv> callbacks or C<psub>
120	blocks.	164	blocks.
121		165
…		…
195	mon $port, $self => "restart";	239	mon $port, $self => "restart";
196		240
197	=cut	241	=cut
198		242
199	sub mon {	243	sub mon {
200	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);	244	my ($noderef, $port) = split /#/, shift, 2;
201		245
202	my $node = $NODE{$noderef} \|\| add_node $noderef;	246	my $node = $NODE{$noderef} \|\| add_node $noderef;
203		247
204	#TODO: ports must not be references	248	my $cb = shift;
205	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {	249
		250	unless (ref $cb) {
206	if (@_) {	251	if (@_) {
207	# send a kill info message	252	# send a kill info message
208	my (@msg) = ($cb, @_);	253	my (@msg) = ($cb, @_);
209	$cb = sub { snd @msg, @_ };	254	$cb = sub { snd @msg, @_ };
210	} else {	255	} else {
…		…
242	my ($port, @refs) = @_;	287	my ($port, @refs) = @_;
243		288
244	mon $port, sub { 0 && @refs }	289	mon $port, sub { 0 && @refs }
245	}	290	}
246		291
		292	=item lnk $port1, $port2
		293
		294	Link two ports. This is simply a shorthand for:
		295
		296	mon $port1, $port2;
		297	mon $port2, $port1;
		298
		299	It means that if either one is killed abnormally, the other one gets
		300	killed as well.
		301
247	=item $local_port = port	302	=item $local_port = port
248		303
249	Create a new local port object that supports message matching.	304	Create a new local port object that can be used either as a pattern
		305	matching port ("full port") or a single-callback port ("miniport"),
		306	depending on how C<rcv> callbacks are bound to the object.
250		307
251	=item $portid = port { my @msg = @_; $finished }	308	=item $portid = port { my @msg = @_; $finished }
252		309
253	Creates a "mini port", that is, a very lightweight port without any	310	Creates a "mini port", that is, a very lightweight port without any
254	pattern matching behind it, and returns its ID.	311	pattern matching behind it, and returns its ID.
…		…
260	The message will be passed as-is, no extra argument (i.e. no port id) will	317	The message will be passed as-is, no extra argument (i.e. no port id) will
261	be passed to the callback.	318	be passed to the callback.
262		319
263	If you need the local port id in the callback, this works nicely:	320	If you need the local port id in the callback, this works nicely:
264		321
265	my $port; $port = miniport {	322	my $port; $port = port {
266	snd $otherport, reply => $port;	323	snd $otherport, reply => $port;
267	};	324	};
268		325
269	=cut	326	=cut
270		327
…		…
331	my ($portid, $name) = @_;	388	my ($portid, $name) = @_;
332		389
333	$REG{$name} = $portid;	390	$REG{$name} = $portid;
334	}	391	}
335		392
		393	=item rcv $portid, $callback->(@msg)
		394
		395	Replaces the callback on the specified miniport (or newly created port
		396	object, see C<port>). Full ports are configured with the following calls:
		397
336	=item rcv $portid, tagstring => $callback->(@msg), ...	398	=item rcv $portid, tagstring => $callback->(@msg), ...
337		399
338	=item rcv $portid, $smartmatch => $callback->(@msg), ...	400	=item rcv $portid, $smartmatch => $callback->(@msg), ...
339		401
340	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...	402	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
…		…
363	also the most efficient match (by far).	425	also the most efficient match (by far).
364		426
365	=cut	427	=cut
366		428
367	sub rcv($@) {	429	sub rcv($@) {
		430	my $portid = shift;
368	my ($noderef, $port) = split /#/, shift, 2;	431	my ($noderef, $port) = split /#/, $port, 2;
369		432
370	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	433	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
371	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";	434	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
372		435
373	my $self = $PORT_DATA{$port}	436	my $self = $PORT_DATA{$port}
…		…
388	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
389	} else {	452	} else {
390	push @{ $self->{any} }, [$cb, $match];	453	push @{ $self->{any} }, [$cb, $match];
391	}	454	}
392	}	455	}
		456
		457	$portid
393	}	458	}
394		459
395	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
396		461
397	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	462	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
434		499
435	=head1 FUNCTIONS FOR NODES	500	=head1 FUNCTIONS FOR NODES
436		501
437	=over 4	502	=over 4
438		503
439	=item become_public endpoint...	504	=item become_public $noderef
440		505
441	Tells the node to become a public node, i.e. reachable from other nodes.	506	Tells the node to become a public node, i.e. reachable from other nodes.
442		507
443	If no arguments are given, or the first argument is C<undef>, then	508	The first argument is the (unresolved) node reference of the local node
444	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	509	(if missing then the empty string is used).
445	local nodename resolves to.
446		510
447	Otherwise the first argument must be an array-reference with transport	511	It is quite common to not specify anything, in which case the local node
448	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	512	tries to listen on the default port, or to only specify a port number, in
449	local nodename is used as hostname). The endpoints are all resolved and	513	which case AnyEvent::MP tries to guess the local addresses.
450	will become the node reference.
451		514
452	=cut	515	=cut
453		516
454	=back	517	=back
455		518
…		…
458	Nodes understand the following messages sent to them. Many of them take	521	Nodes understand the following messages sent to them. Many of them take
459	arguments called C<@reply>, which will simply be used to compose a reply	522	arguments called C<@reply>, which will simply be used to compose a reply
460	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	523	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
461	the remaining arguments are simply the message data.	524	the remaining arguments are simply the message data.
462		525
		526	While other messages exist, they are not public and subject to change.
		527
463	=over 4	528	=over 4
464		529
465	=cut	530	=cut
466		531
467	=item lookup => $name, @reply	532	=item lookup => $name, @reply
…		…
495	snd $NODE, time => $myport, timereply => 1, 2;	560	snd $NODE, time => $myport, timereply => 1, 2;
496	# => snd $myport, timereply => 1, 2, <time>	561	# => snd $myport, timereply => 1, 2, <time>
497		562
498	=back	563	=back
499		564
		565	=head1 AnyEvent::MP vs. Distributed Erlang
		566
		567	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		568	== aemp node, erlang process == aemp port), so many of the documents and
		569	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		570	sample:
		571
		572	http://www.erlang.se/doc/programming_rules.shtml
		573	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		574	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		575	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		576
		577	Despite the similarities, there are also some important differences:
		578
		579	=over 4
		580
		581	=item * Node references contain the recipe on how to contact them.
		582
		583	Erlang relies on special naming and DNS to work everywhere in the
		584	same way. AEMP relies on each node knowing it's own address(es), with
		585	convenience functionality.
		586
		587	This means that AEMP requires a less tightly controlled environment at the
		588	cost of longer node references and a slightly higher management overhead.
		589
		590	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		591
		592	Erlang uses processes that selctively receive messages, and therefore
		593	needs a queue. AEMP is event based, queuing messages would serve no useful
		594	purpose.
		595
		596	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		597
		598	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		599
		600	Sending messages in erlang is synchronous and blocks the process. AEMP
		601	sends are immediate, connection establishment is handled in the
		602	background.
		603
		604	=item * Erlang can silently lose messages, AEMP cannot.
		605
		606	Erlang makes few guarantees on messages delivery - messages can get lost
		607	without any of the processes realising it (i.e. you send messages a, b,
		608	and c, and the other side only receives messages a and c).
		609
		610	AEMP guarantees correct ordering, and the guarantee that there are no
		611	holes in the message sequence.
		612
		613	=item * In erlang, processes can be declared dead and later be found to be
		614	alive.
		615
		616	In erlang it can happen that a monitored process is declared dead and
		617	linked processes get killed, but later it turns out that the process is
		618	still alive - and can receive messages.
		619
		620	In AEMP, when port monitoring detects a port as dead, then that port will
		621	eventually be killed - it cannot happen that a node detects a port as dead
		622	and then later sends messages to it, finding it is still alive.
		623
		624	=item * Erlang can send messages to the wrong port, AEMP does not.
		625
		626	In erlang it is quite possible that a node that restarts reuses a process
		627	ID known to other nodes for a completely different process, causing
		628	messages destined for that process to end up in an unrelated process.
		629
		630	AEMP never reuses port IDs, so old messages or old port IDs floating
		631	around in the network will not be sent to an unrelated port.
		632
		633	=item * Erlang uses unprotected connections, AEMP uses secure
		634	authentication and can use TLS.
		635
		636	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		637	securely authenticate nodes.
		638
		639	=item * The AEMP protocol is optimised for both text-based and binary
		640	communications.
		641
		642	The AEMP protocol, unlike the erlang protocol, supports both
		643	language-independent text-only protocols (good for debugging) and binary,
		644	language-specific serialisers (e.g. Storable).
		645
		646	It has also been carefully designed to be implementable in other languages
		647	with a minimum of work while gracefully degrading fucntionality to make the
		648	protocol simple.
		649
		650	=back
		651
500	=head1 SEE ALSO	652	=head1 SEE ALSO
501		653
502	L<AnyEvent>.	654	L<AnyEvent>.
503		655
504	=head1 AUTHOR	656	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs. Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs.
Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC