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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.21 by root, Tue Aug 4 14:10:51 2009 UTC vs.
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	NODE # returns this node identifier
10	$NODE # contains this node identifier	9	$NODE # contains this node's noderef
		10	NODE # returns this node's noderef
		11	NODE $port # returns the noderef of the port
11		12
		13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# ports are message endpoints
		16
		17	# sending messages
12	snd $port, type => data...;	18	snd $port, type => data...;
		19	snd $port, @msg;
		20	snd @msg_with_first_element_being_a_port;
13		21
		22	# miniports
		23	my $miniport = port { my @msg = @_; 0 };
		24
		25	# full ports
		26	my $port = port;
14	rcv $port, smartmatch => $cb->($port, @msg);	27	rcv $port, smartmatch => $cb->(@msg);
15
16	# examples:
17	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
18	rcv $port1, pong => sub { warn "pong received\n" };	29	rcv $port, pong => sub { warn "pong received\n"; 0 };
19	snd $port2, ping => $port1;	30
		31	# remote ports
		32	my $port = spawn $node, $initfunc, @initdata;
20		33
21	# more, smarter, matches (_any_ is exported by this module)	34	# more, smarter, matches (_any_ is exported by this module)
22	rcv $port, [child_died => $pid] => sub { ...	35	rcv $port, [child_died => $pid] => sub { ...
23	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
24		37
		38	# monitoring
		39	mon $port, $cb->(@msg) # callback is invoked on death
		40	mon $port, $otherport # kill otherport on abnormal death
		41	mon $port, $otherport, @msg # send message on death
		42
25	=head1 DESCRIPTION	43	=head1 DESCRIPTION
26		44
27	This module (-family) implements a simple message passing framework.	45	This module (-family) implements a simple message passing framework.
28		46
29	Despite its simplicity, you can securely message other processes running	47	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	48	on the same or other hosts.
31		49
		50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		51	manual page.
		52
32	At the moment, this module family is severly brokena nd underdocumented,	53	At the moment, this module family is severly broken and underdocumented,
33	so do not use. This was uploaded mainly to reserve the CPAN namespace -	54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
34	stay tuned!	55	stay tuned! The basic API should be finished, however.
35		56
36	=head1 CONCEPTS	57	=head1 CONCEPTS
37		58
38	=over 4	59	=over 4
39		60
40	=item port	61	=item port
41		62
42	A port is something you can send messages to with the C<snd> function, and	63	A port is something you can send messages to (with the C<snd> function).
43	you can register C<rcv> handlers with. All C<rcv> handlers will receive	64
44	messages they match, messages will not be queued.	65	Some ports allow you to register C<rcv> handlers that can match specific
		66	messages. All C<rcv> handlers will receive messages they match, messages
		67	will not be queued.
45		68
46	=item port id - C<noderef#portname>	69	=item port id - C<noderef#portname>
47		70
48	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
49	by a port name (a printable string of unspecified format).	72	separator, and a port name (a printable string of unspecified format). An
		73	exception is the the node port, whose ID is identical to its node
		74	reference.
50		75
51	=item node	76	=item node
52		77
53	A node is a single process containing at least one port - the node	78	A node is a single process containing at least one port - the node
54	port. You can send messages to node ports to let them create new ports,	79	port. You can send messages to node ports to find existing ports or to
55	among other things.	80	create new ports, among other things.
56		81
57	Initially, nodes are either private (single-process only) or hidden	82	Nodes are either private (single-process only), slaves (connected to a
58	(connected to a master node only). Only when they epxlicitly "become	83	master node only) or public nodes (connectable from unrelated nodes).
59	public" can you send them messages from unrelated other nodes.
60		84
61	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
62		86
63	A noderef is a string that either uniquely identifies a given node (for	87	A node reference is a string that either simply identifies the node (for
64	private and hidden nodes), or contains a recipe on how to reach a given	88	private and slave nodes), or contains a recipe on how to reach a given
65	node (for public nodes).	89	node (for public nodes).
66		90
		91	This recipe is simply a comma-separated list of C<address:port> pairs (for
		92	TCP/IP, other protocols might look different).
		93
		94	Node references come in two flavours: resolved (containing only numerical
		95	addresses) or unresolved (where hostnames are used instead of addresses).
		96
		97	Before using an unresolved node reference in a message you first have to
		98	resolve it.
		99
67	=back	100	=back
68		101
69	=head1 VARIABLES/FUNCTIONS	102	=head1 VARIABLES/FUNCTIONS
70		103
71	=over 4	104	=over 4
…		…
82		115
83	use AE ();	116	use AE ();
84		117
85	use base "Exporter";	118	use base "Exporter";
86		119
87	our $VERSION = '0.02';	120	our $VERSION = $AnyEvent::MP::Base::VERSION;
		121
88	our @EXPORT = qw(	122	our @EXPORT = qw(
89	NODE $NODE $PORT snd rcv mon kil _any_	123	NODE $NODE *SELF node_of _any_
90	create_port create_port_on	124	resolve_node initialise_node
		125	snd rcv mon kil reg psub spawn
91	miniport	126	port
92	become_slave become_public
93	);	127	);
94		128
		129	our $SELF;
		130
		131	sub _self_die() {
		132	my $msg = $@;
		133	$msg =~ s/\n+$// unless ref $msg;
		134	kil $SELF, die => $msg;
		135	}
		136
95	=item NODE / $NODE	137	=item $thisnode = NODE / $NODE
96		138
97	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	139	The C<NODE> function returns, and the C<$NODE> variable contains
98	the local node. The value is initialised by a call to C<become_public> or	140	the noderef of the local node. The value is initialised by a call
99	C<become_slave>, after which all local port identifiers become invalid.	141	to C<become_public> or C<become_slave>, after which all local port
		142	identifiers become invalid.
100		143
		144	=item $noderef = node_of $port
		145
		146	Extracts and returns the noderef from a portid or a noderef.
		147
		148	=item initialise_node $noderef, $seednode, $seednode...
		149
		150	=item initialise_node "slave/", $master, $master...
		151
		152	Before a node can talk to other nodes on the network it has to initialise
		153	itself - the minimum a node needs to know is it's own name, and optionally
		154	it should know the noderefs of some other nodes in the network.
		155
		156	This function initialises a node - it must be called exactly once (or
		157	never) before calling other AnyEvent::MP functions.
		158
		159	All arguments are noderefs, which can be either resolved or unresolved.
		160
		161	There are two types of networked nodes, public nodes and slave nodes:
		162
		163	=over 4
		164
		165	=item public nodes
		166
		167	For public nodes, C<$noderef> must either be a (possibly unresolved)
		168	noderef, in which case it will be resolved, or C<undef> (or missing), in
		169	which case the noderef will be guessed.
		170
		171	Afterwards, the node will bind itself on all endpoints and try to connect
		172	to all additional C<$seednodes> that are specified. Seednodes are optional
		173	and can be used to quickly bootstrap the node into an existing network.
		174
		175	=item slave nodes
		176
		177	When the C<$noderef> is the special string C<slave/>, then the node will
		178	become a slave node. Slave nodes cannot be contacted from outside and will
		179	route most of their traffic to the master node that they attach to.
		180
		181	At least one additional noderef is required: The node will try to connect
		182	to all of them and will become a slave attached to the first node it can
		183	successfully connect to.
		184
		185	=back
		186
		187	This function will block until all nodes have been resolved and, for slave
		188	nodes, until it has successfully established a connection to a master
		189	server.
		190
		191	Example: become a public node listening on the default node.
		192
		193	initialise_node;
		194
		195	Example: become a public node, and try to contact some well-known master
		196	servers to become part of the network.
		197
		198	initialise_node undef, "master1", "master2";
		199
		200	Example: become a public node listening on port C<4041>.
		201
		202	initialise_node 4041;
		203
		204	Example: become a public node, only visible on localhost port 4044.
		205
		206	initialise_node "locahost:4044";
		207
		208	Example: become a slave node to any of the specified master servers.
		209
		210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		211
		212	=item $cv = resolve_node $noderef
		213
		214	Takes an unresolved node reference that may contain hostnames and
		215	abbreviated IDs, resolves all of them and returns a resolved node
		216	reference.
		217
		218	In addition to C<address:port> pairs allowed in resolved noderefs, the
		219	following forms are supported:
		220
		221	=over 4
		222
		223	=item the empty string
		224
		225	An empty-string component gets resolved as if the default port (4040) was
		226	specified.
		227
		228	=item naked port numbers (e.g. C<1234>)
		229
		230	These are resolved by prepending the local nodename and a colon, to be
		231	further resolved.
		232
		233	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		234
		235	These are resolved by using AnyEvent::DNS to resolve them, optionally
		236	looking up SRV records for the C<aemp=4040> port, if no port was
		237	specified.
		238
		239	=back
		240
		241	=item $SELF
		242
		243	Contains the current port id while executing C<rcv> callbacks or C<psub>
		244	blocks.
		245
		246	=item SELF, %SELF, @SELF...
		247
		248	Due to some quirks in how perl exports variables, it is impossible to
		249	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		250	module, but only C<$SELF> is currently used.
		251
101	=item snd $portid, type => @data	252	=item snd $port, type => @data
102		253
103	=item snd $portid, @msg	254	=item snd $port, @msg
104		255
105	Send the given message to the given port ID, which can identify either	256	Send the given message to the given port ID, which can identify either
106	a local or a remote port, and can be either a string or soemthignt hat	257	a local or a remote port, and can be either a string or soemthignt hat
107	stringifies a sa port ID (such as a port object :).	258	stringifies a sa port ID (such as a port object :).
108		259
…		…
118	JSON is used, then only strings, numbers and arrays and hashes consisting	269	JSON is used, then only strings, numbers and arrays and hashes consisting
119	of those are allowed (no objects). When Storable is used, then anything	270	of those are allowed (no objects). When Storable is used, then anything
120	that Storable can serialise and deserialise is allowed, and for the local	271	that Storable can serialise and deserialise is allowed, and for the local
121	node, anything can be passed.	272	node, anything can be passed.
122		273
		274	=item $local_port = port
		275
		276	Create a new local port object that can be used either as a pattern
		277	matching port ("full port") or a single-callback port ("miniport"),
		278	depending on how C<rcv> callbacks are bound to the object.
		279
		280	=item $port = port { my @msg = @_; $finished }
		281
		282	Creates a "miniport", that is, a very lightweight port without any pattern
		283	matching behind it, and returns its ID. Semantically the same as creating
		284	a port and calling C<rcv $port, $callback> on it.
		285
		286	The block will be called for every message received on the port. When the
		287	callback returns a true value its job is considered "done" and the port
		288	will be destroyed. Otherwise it will stay alive.
		289
		290	The message will be passed as-is, no extra argument (i.e. no port id) will
		291	be passed to the callback.
		292
		293	If you need the local port id in the callback, this works nicely:
		294
		295	my $port; $port = port {
		296	snd $otherport, reply => $port;
		297	};
		298
		299	=cut
		300
		301	sub rcv($@);
		302
		303	sub port(;&) {
		304	my $id = "$UNIQ." . $ID++;
		305	my $port = "$NODE#$id";
		306
		307	if (@_) {
		308	rcv $port, shift;
		309	} else {
		310	$PORT{$id} = sub { }; # nop
		311	}
		312
		313	$port
		314	}
		315
		316	=item reg $port, $name
		317
		318	=item reg $name
		319
		320	Registers the given port (or C<$SELF><<< if missing) under the name
		321	C<$name>. If the name already exists it is replaced.
		322
		323	A port can only be registered under one well known name.
		324
		325	A port automatically becomes unregistered when it is killed.
		326
		327	=cut
		328
		329	sub reg(@) {
		330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		331
		332	$REG{$_[0]} = $port;
		333	}
		334
		335	=item rcv $port, $callback->(@msg)
		336
		337	Replaces the callback on the specified miniport (after converting it to
		338	one if required).
		339
		340	=item rcv $port, tagstring => $callback->(@msg), ...
		341
		342	=item rcv $port, $smartmatch => $callback->(@msg), ...
		343
		344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		345
		346	Register callbacks to be called on matching messages on the given full
		347	port (after converting it to one if required) and return the port.
		348
		349	The callback has to return a true value when its work is done, after
		350	which is will be removed, or a false value in which case it will stay
		351	registered.
		352
		353	The global C<$SELF> (exported by this module) contains C<$port> while
		354	executing the callback.
		355
		356	Runtime errors during callback execution will result in the port being
		357	C<kil>ed.
		358
		359	If the match is an array reference, then it will be matched against the
		360	first elements of the message, otherwise only the first element is being
		361	matched.
		362
		363	Any element in the match that is specified as C<_any_> (a function
		364	exported by this module) matches any single element of the message.
		365
		366	While not required, it is highly recommended that the first matching
		367	element is a string identifying the message. The one-string-only match is
		368	also the most efficient match (by far).
		369
		370	Example: create a port and bind receivers on it in one go.
		371
		372	my $port = rcv port,
		373	msg1 => sub { ...; 0 },
		374	msg2 => sub { ...; 0 },
		375	;
		376
		377	Example: create a port, bind receivers and send it in a message elsewhere
		378	in one go:
		379
		380	snd $otherport, reply =>
		381	rcv port,
		382	msg1 => sub { ...; 0 },
		383	...
		384	;
		385
		386	=cut
		387
		388	sub rcv($@) {
		389	my $port = shift;
		390	my ($noderef, $portid) = split /#/, $port, 2;
		391
		392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		393	or Carp::croak "$port: rcv can only be called on local ports, caught";
		394
		395	if (@_ == 1) {
		396	my $cb = shift;
		397	delete $PORT_DATA{$portid};
		398	$PORT{$portid} = sub {
		399	local $SELF = $port;
		400	eval {
		401	&$cb
		402	and kil $port;
		403	};
		404	_self_die if $@;
		405	};
		406	} else {
		407	my $self = $PORT_DATA{$portid} \|\|= do {
		408	my $self = bless {
		409	id => $port,
		410	}, "AnyEvent::MP::Port";
		411
		412	$PORT{$portid} = sub {
		413	local $SELF = $port;
		414
		415	eval {
		416	for (@{ $self->{rc0}{$_[0]} }) {
		417	$_ && &{$_->[0]}
		418	&& undef $_;
		419	}
		420
		421	for (@{ $self->{rcv}{$_[0]} }) {
		422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		423	&& &{$_->[0]}
		424	&& undef $_;
		425	}
		426
		427	for (@{ $self->{any} }) {
		428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		429	&& &{$_->[0]}
		430	&& undef $_;
		431	}
		432	};
		433	_self_die if $@;
		434	};
		435
		436	$self
		437	};
		438
		439	"AnyEvent::MP::Port" eq ref $self
		440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		441
		442	while (@_) {
		443	my ($match, $cb) = splice @_, 0, 2;
		444
		445	if (!ref $match) {
		446	push @{ $self->{rc0}{$match} }, [$cb];
		447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		448	my ($type, @match) = @$match;
		449	@match
		450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
		452	} else {
		453	push @{ $self->{any} }, [$cb, $match];
		454	}
		455	}
		456	}
		457
		458	$port
		459	}
		460
		461	=item $closure = psub { BLOCK }
		462
		463	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
		464	closure is executed, sets up the environment in the same way as in C<rcv>
		465	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		466
		467	This is useful when you register callbacks from C<rcv> callbacks:
		468
		469	rcv delayed_reply => sub {
		470	my ($delay, @reply) = @_;
		471	my $timer = AE::timer $delay, 0, psub {
		472	snd @reply, $SELF;
		473	};
		474	};
		475
		476	=cut
		477
		478	sub psub(&) {
		479	my $cb = shift;
		480
		481	my $port = $SELF
		482	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		483
		484	sub {
		485	local $SELF = $port;
		486
		487	if (wantarray) {
		488	my @res = eval { &$cb };
		489	_self_die if $@;
		490	@res
		491	} else {
		492	my $res = eval { &$cb };
		493	_self_die if $@;
		494	$res
		495	}
		496	}
		497	}
		498
123	=item $guard = mon $portid, $cb->()	499	=item $guard = mon $port, $cb->(@reason)
124		500
125	=item $guard = mon $portid, $otherport	501	=item $guard = mon $port, $rcvport
126		502
		503	=item $guard = mon $port
		504
127	=item $guard = mon $portid, $otherport, @msg	505	=item $guard = mon $port, $rcvport, @msg
128		506
129	Monitor the given port and call the given callback when the port is	507	Monitor the given port and do something when the port is killed or
130	destroyed or connection to it's node is lost.	508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
131		510
132	#TODO	511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
		519	In the first form (callback), the callback is simply called with any
		520	number of C<@reason> elements (no @reason means that the port was deleted
		521	"normally"). Note also that I<< the callback B<must> never die >>, so use
		522	C<eval> if unsure.
		523
		524	In the second form (another port given), the other port (C<$rcvport>)
		525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		526	"normal" kils nothing happens, while under all other conditions, the other
		527	port is killed with the same reason.
		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
		532	In the last form (message), a message of the form C<@msg, @reason> will be
		533	C<snd>.
		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
		541
		542	Example: call a given callback when C<$port> is killed.
		543
		544	mon $port, sub { warn "port died because of <@_>\n" };
		545
		546	Example: kill ourselves when C<$port> is killed abnormally.
		547
		548	mon $port;
		549
		550	Example: send us a restart message when another C<$port> is killed.
		551
		552	mon $port, $self => "restart";
133		553
134	=cut	554	=cut
135		555
136	sub mon {	556	sub mon {
137	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);	557	my ($noderef, $port) = split /#/, shift, 2;
138		558
139	my $node = AnyEvent::MP::Base::add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
140		560
141	#TODO: ports must not be references	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
142	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {	562
		563	unless (ref $cb) {
143	if (@_) {	564	if (@_) {
144	# send a kill info message	565	# send a kill info message
145	my (@msg) = ($cb, @_);	566	my (@msg) = ($cb, @_);
146	$cb = sub { snd @msg, @_ };	567	$cb = sub { snd @msg, @_ };
147	} else {	568	} else {
148	# simply kill other port	569	# simply kill other port
149	my $port = $cb;	570	my $port = $cb;
150	$cb = sub { kil $port, @_ };	571	$cb = sub { kil $port, @_ if @_ };
151	}	572	}
152	}	573	}
153		574
154	$node->monitor ($port, $cb);	575	$node->monitor ($port, $cb);
155		576
…		…
176	=cut	597	=cut
177		598
178	sub mon_guard {	599	sub mon_guard {
179	my ($port, @refs) = @_;	600	my ($port, @refs) = @_;
180		601
		602	#TODO: mon-less form?
		603
181	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
182	}	605	}
183		606
184	=item $local_port = create_port	607	=item kil $port[, @reason]
185		608
186	Create a new local port object. See the next section for allowed methods.	609	Kill the specified port with the given C<@reason>.
187		610
188	=cut	611	If no C<@reason> is specified, then the port is killed "normally" (linked
		612	ports will not be kileld, or even notified).
189		613
190	sub create_port {	614	Otherwise, linked ports get killed with the same reason (second form of
191	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;	615	C<mon>, see below).
192		616
193	my $self = bless {	617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
194	id => "$NODE#$id",	618	will be reported as reason C<< die => $@ >>.
195	}, "AnyEvent::MP::Port";
196		619
197	$AnyEvent::MP::Base::PORT{$id} = sub {	620	Transport/communication errors are reported as C<< transport_error =>
198	unshift @_, $self;	621	$message >>.
199		622
200	for (@{ $self->{rc0}{$_[1]} }) {	623	=cut
201	$_ && &{$_->[0]}	624
202	&& undef $_;	625	=item $port = spawn $node, $initfunc[, @initdata]
		626
		627	Creates a port on the node C<$node> (which can also be a port ID, in which
		628	case it's the node where that port resides).
		629
		630	The port ID of the newly created port is return immediately, and it is
		631	permissible to immediately start sending messages or monitor the port.
		632
		633	After the port has been created, the init function is
		634	called. This function must be a fully-qualified function name
		635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		636	program, use C<::name>.
		637
		638	If the function doesn't exist, then the node tries to C<require>
		639	the package, then the package above the package and so on (e.g.
		640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		641	exists or it runs out of package names.
		642
		643	The init function is then called with the newly-created port as context
		644	object (C<$SELF>) and the C<@initdata> values as arguments.
		645
		646	A common idiom is to pass your own port, monitor the spawned port, and
		647	in the init function, monitor the original port. This two-way monitoring
		648	ensures that both ports get cleaned up when there is a problem.
		649
		650	Example: spawn a chat server port on C<$othernode>.
		651
		652	# this node, executed from within a port context:
		653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		654	mon $server;
		655
		656	# init function on C<$othernode>
		657	sub connect {
		658	my ($srcport) = @_;
		659
		660	mon $srcport;
		661
		662	rcv $SELF, sub {
		663	...
203	}	664	};
		665	}
204		666
205	for (@{ $self->{rcv}{$_[1]} }) {	667	=cut
206	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
207	&& &{$_->[0]}
208	&& undef $_;
209	}
210		668
211	for (@{ $self->{any} }) {	669	sub _spawn {
212	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	670	my $port = shift;
213	&& &{$_->[0]}	671	my $init = shift;
214	&& undef $_;	672
215	}	673	local $SELF = "$NODE#$port";
		674	eval {
		675	&{ load_func $init }
216	};	676	};
217		677	_self_die if $@;
218	$self
219	}	678	}
220		679
221	=item $portid = miniport { my @msg = @_; $finished }	680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
222		682
223	Creates a "mini port", that is, a very lightweight port without any	683	my $id = "$RUNIQ." . $ID++;
224	pattern matching behind it, and returns its ID.
225		684
226	The block will be called for every message received on the port. When the	685	$_[0] =~ /::/
227	callback returns a true value its job is considered "done" and the port	686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
228	will be destroyed. Otherwise it will stay alive.
229		687
230	The message will be passed as-is, no extra argument (i.e. no port id) will	688	($NODE{$noderef} \|\| add_node $noderef)
231	be passed to the callback.	689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
232		690
233	If you need the local port id in the callback, this works nicely:	691	"$noderef#$id"
234
235	my $port; $port = miniport {
236	snd $otherport, reply => $port;
237	};
238
239	=cut
240
241	sub miniport(&) {
242	my $cb = shift;
243	my $id = "$AnyEvent::MP::Base::UNIQ." . $AnyEvent::MP::Base::ID++;
244
245	$AnyEvent::MP::Base::PORT{$id} = sub {
246	&$cb
247	and kil $id;
248	};
249
250	"$NODE#$id"
251	}	692	}
252
253	package AnyEvent::MP::Port;
254
255	=back
256
257	=head1 METHODS FOR PORT OBJECTS
258
259	=over 4
260
261	=item "$port"
262
263	A port object stringifies to its port ID, so can be used directly for
264	C<snd> operations.
265
266	=cut
267
268	use overload
269	'""' => sub { $_[0]{id} },
270	fallback => 1;
271
272	sub TO_JSON { $_[0]{id} }
273
274	=item $port->rcv (type => $callback->($port, @msg))
275
276	=item $port->rcv ($smartmatch => $callback->($port, @msg))
277
278	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))
279
280	Register a callback on the given port.
281
282	The callback has to return a true value when its work is done, after
283	which is will be removed, or a false value in which case it will stay
284	registered.
285
286	If the match is an array reference, then it will be matched against the
287	first elements of the message, otherwise only the first element is being
288	matched.
289
290	Any element in the match that is specified as C<_any_> (a function
291	exported by this module) matches any single element of the message.
292
293	While not required, it is highly recommended that the first matching
294	element is a string identifying the message. The one-string-only match is
295	also the most efficient match (by far).
296
297	=cut
298
299	sub rcv($@) {
300	my ($self, $match, $cb) = @_;
301
302	if (!ref $match) {
303	push @{ $self->{rc0}{$match} }, [$cb];
304	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
305	my ($type, @match) = @$match;
306	@match
307	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
308	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
309	} else {
310	push @{ $self->{any} }, [$cb, $match];
311	}
312	}
313
314	=item $port->register ($name)
315
316	Registers the given port under the well known name C<$name>. If the name
317	already exists it is replaced.
318
319	A port can only be registered under one well known name.
320
321	=cut
322
323	sub register {
324	my ($self, $name) = @_;
325
326	$self->{wkname} = $name;
327	$AnyEvent::MP::Base::WKP{$name} = "$self";
328	}
329
330	=item $port->destroy
331
332	Explicitly destroy/remove/nuke/vaporise the port.
333
334	Ports are normally kept alive by their mere existance alone, and need to
335	be destroyed explicitly.
336
337	=cut
338
339	sub destroy {
340	my ($self) = @_;
341
342	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
343
344	AnyEvent::MP::Base::kil $self->{id};
345	}
346
347	=back
348
349	=head1 FUNCTIONS FOR NODES
350
351	=over 4
352
353	=item mon $noderef, $callback->($noderef, $status, $)
354
355	Monitors the given noderef.
356
357	=item become_public endpoint...
358
359	Tells the node to become a public node, i.e. reachable from other nodes.
360
361	If no arguments are given, or the first argument is C<undef>, then
362	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
363	local nodename resolves to.
364
365	Otherwise the first argument must be an array-reference with transport
366	endpoints ("ip:port", "hostname:port") or port numbers (in which case the
367	local nodename is used as hostname). The endpoints are all resolved and
368	will become the node reference.
369
370	=cut
371		693
372	=back	694	=back
373		695
374	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
375		697
376	Nodes understand the following messages sent to them. Many of them take	698	Nodes understand the following messages sent to them. Many of them take
377	arguments called C<@reply>, which will simply be used to compose a reply	699	arguments called C<@reply>, which will simply be used to compose a reply
378	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
379	the remaining arguments are simply the message data.	701	the remaining arguments are simply the message data.
380		702
		703	While other messages exist, they are not public and subject to change.
		704
381	=over 4	705	=over 4
382		706
383	=cut	707	=cut
384		708
385	=item wkp => $name, @reply	709	=item lookup => $name, @reply
386		710
387	Replies with the port ID of the specified well-known port, or C<undef>.	711	Replies with the port ID of the specified well-known port, or C<undef>.
388		712
389	=item devnull => ...	713	=item devnull => ...
390		714
…		…
413	snd $NODE, time => $myport, timereply => 1, 2;	737	snd $NODE, time => $myport, timereply => 1, 2;
414	# => snd $myport, timereply => 1, 2, <time>	738	# => snd $myport, timereply => 1, 2, <time>
415		739
416	=back	740	=back
417		741
		742	=head1 AnyEvent::MP vs. Distributed Erlang
		743
		744	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		745	== aemp node, Erlang process == aemp port), so many of the documents and
		746	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		747	sample:
		748
		749	http://www.Erlang.se/doc/programming_rules.shtml
		750	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		751	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		752	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		753
		754	Despite the similarities, there are also some important differences:
		755
		756	=over 4
		757
		758	=item * Node references contain the recipe on how to contact them.
		759
		760	Erlang relies on special naming and DNS to work everywhere in the
		761	same way. AEMP relies on each node knowing it's own address(es), with
		762	convenience functionality.
		763
		764	This means that AEMP requires a less tightly controlled environment at the
		765	cost of longer node references and a slightly higher management overhead.
		766
		767	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		768
		769	Erlang uses processes that selctively receive messages, and therefore
		770	needs a queue. AEMP is event based, queuing messages would serve no useful
		771	purpose.
		772
		773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		774
		775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		776
		777	Sending messages in Erlang is synchronous and blocks the process. AEMP
		778	sends are immediate, connection establishment is handled in the
		779	background.
		780
		781	=item * Erlang can silently lose messages, AEMP cannot.
		782
		783	Erlang makes few guarantees on messages delivery - messages can get lost
		784	without any of the processes realising it (i.e. you send messages a, b,
		785	and c, and the other side only receives messages a and c).
		786
		787	AEMP guarantees correct ordering, and the guarantee that there are no
		788	holes in the message sequence.
		789
		790	=item * In Erlang, processes can be declared dead and later be found to be
		791	alive.
		792
		793	In Erlang it can happen that a monitored process is declared dead and
		794	linked processes get killed, but later it turns out that the process is
		795	still alive - and can receive messages.
		796
		797	In AEMP, when port monitoring detects a port as dead, then that port will
		798	eventually be killed - it cannot happen that a node detects a port as dead
		799	and then later sends messages to it, finding it is still alive.
		800
		801	=item * Erlang can send messages to the wrong port, AEMP does not.
		802
		803	In Erlang it is quite possible that a node that restarts reuses a process
		804	ID known to other nodes for a completely different process, causing
		805	messages destined for that process to end up in an unrelated process.
		806
		807	AEMP never reuses port IDs, so old messages or old port IDs floating
		808	around in the network will not be sent to an unrelated port.
		809
		810	=item * Erlang uses unprotected connections, AEMP uses secure
		811	authentication and can use TLS.
		812
		813	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		814	securely authenticate nodes.
		815
		816	=item * The AEMP protocol is optimised for both text-based and binary
		817	communications.
		818
		819	The AEMP protocol, unlike the Erlang protocol, supports both
		820	language-independent text-only protocols (good for debugging) and binary,
		821	language-specific serialisers (e.g. Storable).
		822
		823	It has also been carefully designed to be implementable in other languages
		824	with a minimum of work while gracefully degrading fucntionality to make the
		825	protocol simple.
		826
		827	=item * AEMP has more flexible monitoring options than Erlang.
		828
		829	In Erlang, you can chose to receive I<all> exit signals as messages
		830	or I<none>, there is no in-between, so monitoring single processes is
		831	difficult to implement. Monitoring in AEMP is more flexible than in
		832	Erlang, as one can choose between automatic kill, exit message or callback
		833	on a per-process basis.
		834
		835	=item * Erlang tries to hide remote/local connections, AEMP does not.
		836
		837	Monitoring in Erlang is not an indicator of process death/crashes,
		838	as linking is (except linking is unreliable in Erlang).
		839
		840	In AEMP, you don't "look up" registered port names or send to named ports
		841	that might or might not be persistent. Instead, you normally spawn a port
		842	on the remote node. The init function monitors the you, and you monitor
		843	the remote port. Since both monitors are local to the node, they are much
		844	more reliable.
		845
		846	This also saves round-trips and avoids sending messages to the wrong port
		847	(hard to do in Erlang).
		848
		849	=back
		850
418	=head1 SEE ALSO	851	=head1 SEE ALSO
419		852
420	L<AnyEvent>.	853	L<AnyEvent>.
421		854
422	=head1 AUTHOR	855	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.21 by root, Tue Aug 4 14:10:51 2009 UTC vs. Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.21 by root, Tue Aug 4 14:10:51 2009 UTC vs.
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC