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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.25 by root, Tue Aug 4 21:07:37 2009 UTC vs.
Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC

…		…
43		43
44	=over 4	44	=over 4
45		45
46	=item port	46	=item port
47		47
48	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).
49	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
50	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.
51		53
52	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
53		55
54	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
55	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.
56		60
57	=item node	61	=item node
58		62
59	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
60	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
61	among other things.	65	create new ports, among other things.
62		66
63	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
64	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
65	public" can you send them messages from unrelated other nodes.
66		69
67	=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>
68		71
69	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
70	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
71	node (for public nodes).	74	node (for public nodes).
		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.
72		84
73	=back	85	=back
74		86
75	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
76		88
…		…
91	use base "Exporter";	103	use base "Exporter";
92		104
93	our $VERSION = '0.1';	105	our $VERSION = '0.1';
94	our @EXPORT = qw(	106	our @EXPORT = qw(
95	NODE $NODE *SELF node_of _any_	107	NODE $NODE *SELF node_of _any_
96	become_slave become_public	108	resolve_node initialise_node
97	snd rcv mon kil reg psub	109	snd rcv mon kil reg psub
98	port	110	port
99	);	111	);
100		112
101	our $SELF;	113	our $SELF;
…		…
115		127
116	=item $noderef = node_of $portid	128	=item $noderef = node_of $portid
117		129
118	Extracts and returns the noderef from a portid or a noderef.	130	Extracts and returns the noderef from a portid or a noderef.
119		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
120	=item $SELF	161	=item $SELF
121		162
122	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>
123	blocks.	164	blocks.
124		165
…		…
198	mon $port, $self => "restart";	239	mon $port, $self => "restart";
199		240
200	=cut	241	=cut
201		242
202	sub mon {	243	sub mon {
203	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);	244	my ($noderef, $port) = split /#/, shift, 2;
204		245
205	my $node = $NODE{$noderef} \|\| add_node $noderef;	246	my $node = $NODE{$noderef} \|\| add_node $noderef;
206		247
207	#TODO: ports must not be references	248	my $cb = shift;
208	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {	249
		250	unless (ref $cb) {
209	if (@_) {	251	if (@_) {
210	# send a kill info message	252	# send a kill info message
211	my (@msg) = ($cb, @_);	253	my (@msg) = ($cb, @_);
212	$cb = sub { snd @msg, @_ };	254	$cb = sub { snd @msg, @_ };
213	} else {	255	} else {
…		…
257	It means that if either one is killed abnormally, the other one gets	299	It means that if either one is killed abnormally, the other one gets
258	killed as well.	300	killed as well.
259		301
260	=item $local_port = port	302	=item $local_port = port
261		303
262	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.
263		307
264	=item $portid = port { my @msg = @_; $finished }	308	=item $portid = port { my @msg = @_; $finished }
265		309
266	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
267	pattern matching behind it, and returns its ID.	311	pattern matching behind it, and returns its ID.
…		…
273	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
274	be passed to the callback.	318	be passed to the callback.
275		319
276	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:
277		321
278	my $port; $port = miniport {	322	my $port; $port = port {
279	snd $otherport, reply => $port;	323	snd $otherport, reply => $port;
280	};	324	};
281		325
282	=cut	326	=cut
283		327
…		…
344	my ($portid, $name) = @_;	388	my ($portid, $name) = @_;
345		389
346	$REG{$name} = $portid;	390	$REG{$name} = $portid;
347	}	391	}
348		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
349	=item rcv $portid, tagstring => $callback->(@msg), ...	398	=item rcv $portid, tagstring => $callback->(@msg), ...
350		399
351	=item rcv $portid, $smartmatch => $callback->(@msg), ...	400	=item rcv $portid, $smartmatch => $callback->(@msg), ...
352		401
353	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...	402	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
…		…
376	also the most efficient match (by far).	425	also the most efficient match (by far).
377		426
378	=cut	427	=cut
379		428
380	sub rcv($@) {	429	sub rcv($@) {
		430	my $portid = shift;
381	my ($noderef, $port) = split /#/, shift, 2;	431	my ($noderef, $port) = split /#/, $port, 2;
382		432
383	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	433	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
384	or Carp::croak "$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";
385		435
386	my $self = $PORT_DATA{$port}	436	my $self = $PORT_DATA{$port}
…		…
401	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
402	} else {	452	} else {
403	push @{ $self->{any} }, [$cb, $match];	453	push @{ $self->{any} }, [$cb, $match];
404	}	454	}
405	}	455	}
		456
		457	$portid
406	}	458	}
407		459
408	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
409		461
410	Remembers C<$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
…		…
447		499
448	=head1 FUNCTIONS FOR NODES	500	=head1 FUNCTIONS FOR NODES
449		501
450	=over 4	502	=over 4
451		503
452	=item become_public endpoint...	504	=item become_public $noderef
453		505
454	Tells the node to become a public node, i.e. reachable from other nodes.	506	Tells the node to become a public node, i.e. reachable from other nodes.
455		507
456	If no arguments are given, or the first argument is C<undef>, then	508	The first argument is the (unresolved) node reference of the local node
457	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	509	(if missing then the empty string is used).
458	local nodename resolves to.
459		510
460	Otherwise the first argument must be an array-reference with transport	511	It is quite common to not specify anything, in which case the local node
461	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	512	tries to listen on the default port, or to only specify a port number, in
462	local nodename is used as hostname). The endpoints are all resolved and	513	which case AnyEvent::MP tries to guess the local addresses.
463	will become the node reference.
464		514
465	=cut	515	=cut
466		516
467	=back	517	=back
468		518
…		…
471	Nodes understand the following messages sent to them. Many of them take	521	Nodes understand the following messages sent to them. Many of them take
472	arguments called C<@reply>, which will simply be used to compose a reply	522	arguments called C<@reply>, which will simply be used to compose a reply
473	message - C<$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
474	the remaining arguments are simply the message data.	524	the remaining arguments are simply the message data.
475		525
		526	While other messages exist, they are not public and subject to change.
		527
476	=over 4	528	=over 4
477		529
478	=cut	530	=cut
479		531
480	=item lookup => $name, @reply	532	=item lookup => $name, @reply
…		…
508	snd $NODE, time => $myport, timereply => 1, 2;	560	snd $NODE, time => $myport, timereply => 1, 2;
509	# => snd $myport, timereply => 1, 2, <time>	561	# => snd $myport, timereply => 1, 2, <time>
510		562
511	=back	563	=back
512		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
513	=head1 SEE ALSO	652	=head1 SEE ALSO
514		653
515	L<AnyEvent>.	654	L<AnyEvent>.
516		655
517	=head1 AUTHOR	656	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.25 by root, Tue Aug 4 21:07:37 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 1.25 by root, Tue Aug 4 21:07:37 2009 UTC vs.
Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC