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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC vs.
Revision 1.153 by root, Sat Nov 2 01:30:49 2019 UTC

…		…
30	rcv $port, pong => sub { warn "pong received\n" };	30	rcv $port, pong => sub { warn "pong received\n" };
31		31
32	# create a port on another node	32	# create a port on another node
33	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
34		34
35	# destroy a prot again	35	# destroy a port again
36	kil $port; # "normal" kill	36	kil $port; # "normal" kill
37	kil $port, my_error => "everything is broken"; # error kill	37	kil $port, my_error => "everything is broken"; # error kill
38		38
39	# monitoring	39	# monitoring
40	mon $localport, $cb->(@msg) # callback is invoked on death	40	mon $port, $cb->(@msg) # callback is invoked on death
41	mon $localport, $otherport # kill otherport on abnormal death	41	mon $port, $localport # kill localport on abnormal death
42	mon $localport, $otherport, @msg # send message on death	42	mon $port, $localport, @msg # send message on death
43		43
44	# temporarily execute code in port context	44	# temporarily execute code in port context
45	peval $port, sub { die "kill the port!" };	45	peval $port, sub { die "kill the port!" };
46		46
47	# execute callbacks in $SELF port context	47	# execute callbacks in $SELF port context
48	my $timer = AE::timer 1, 0, psub {	48	my $timer = AE::timer 1, 0, psub {
49	die "kill the port, delayed";	49	die "kill the port, delayed";
50	};	50	};
51		51
52	=head1 CURRENT STATUS	52	# distributed database - modification
		53	db_set $family => $subkey [=> $value] # add a subkey
		54	db_del $family => $subkey... # delete one or more subkeys
		55	db_reg $family => $port [=> $value] # register a port
53		56
54	bin/aemp - stable.	57	# distributed database - queries
55	AnyEvent::MP - stable API, should work.	58	db_family $family => $cb->(\%familyhash)
56	AnyEvent::MP::Intro - explains most concepts.	59	db_keys $family => $cb->(\@keys)
57	AnyEvent::MP::Kernel - mostly stable API.	60	db_values $family => $cb->(\@values)
58	AnyEvent::MP::Global - stable API.	61
		62	# distributed database - monitoring a family
		63	db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
59		64
60	=head1 DESCRIPTION	65	=head1 DESCRIPTION
61		66
62	This module (-family) implements a simple message passing framework.	67	This module (-family) implements a simple message passing framework.
63		68
…		…
78		83
79	Ports allow you to register C<rcv> handlers that can match all or just	84	Ports allow you to register C<rcv> handlers that can match all or just
80	some messages. Messages send to ports will not be queued, regardless of	85	some messages. Messages send to ports will not be queued, regardless of
81	anything was listening for them or not.	86	anything was listening for them or not.
82		87
		88	Ports are represented by (printable) strings called "port IDs".
		89
83	=item port ID - C<nodeid#portname>	90	=item port ID - C<nodeid#portname>
84		91
85	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as	92	A port ID is the concatenation of a node ID, a hash-mark (C<#>)
86	separator, and a port name (a printable string of unspecified format).	93	as separator, and a port name (a printable string of unspecified
		94	format created by AnyEvent::MP).
87		95
88	=item node	96	=item node
89		97
90	A node is a single process containing at least one port - the node port,	98	A node is a single process containing at least one port - the node port,
91	which enables nodes to manage each other remotely, and to create new	99	which enables nodes to manage each other remotely, and to create new
92	ports.	100	ports.
93		101
94	Nodes are either public (have one or more listening ports) or private	102	Nodes are either public (have one or more listening ports) or private
95	(no listening ports). Private nodes cannot talk to other private nodes	103	(no listening ports). Private nodes cannot talk to other private nodes
96	currently.	104	currently, but all nodes can talk to public nodes.
97		105
		106	Nodes is represented by (printable) strings called "node IDs".
		107
98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>	108	=item node ID - C<[A-Za-z0-9_\-.:]*>
99		109
100	A node ID is a string that uniquely identifies the node within a	110	A node ID is a string that uniquely identifies the node within a
101	network. Depending on the configuration used, node IDs can look like a	111	network. Depending on the configuration used, node IDs can look like a
102	hostname, a hostname and a port, or a random string. AnyEvent::MP itself	112	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
103	doesn't interpret node IDs in any way.	113	doesn't interpret node IDs in any way except to uniquely identify a node.
104		114
105	=item binds - C<ip:port>	115	=item binds - C<ip:port>
106		116
107	Nodes can only talk to each other by creating some kind of connection to	117	Nodes can only talk to each other by creating some kind of connection to
108	each other. To do this, nodes should listen on one or more local transport	118	each other. To do this, nodes should listen on one or more local transport
		119	endpoints - binds.
		120
109	endpoints - binds. Currently, only standard C<ip:port> specifications can	121	Currently, only standard C<ip:port> specifications can be used, which
110	be used, which specify TCP ports to listen on.	122	specify TCP ports to listen on. So a bind is basically just a tcp socket
		123	in listening mode that accepts connections from other nodes.
111		124
112	=item seed nodes	125	=item seed nodes
113		126
114	When a node starts, it knows nothing about the network. To teach the node	127	When a node starts, it knows nothing about the network it is in - it
115	about the network it first has to contact some other node within the	128	needs to connect to at least one other node that is already in the
116	network. This node is called a seed.	129	network. These other nodes are called "seed nodes".
117		130
118	Apart from the fact that other nodes know them as seed nodes and they have	131	Seed nodes themselves are not special - they are seed nodes only because
119	to have fixed listening addresses, seed nodes are perfectly normal nodes -	132	some other node I<uses> them as such, but any node can be used as seed
120	any node can function as a seed node for others.	133	node for other nodes, and eahc node can use a different set of seed nodes.
121		134
122	In addition to discovering the network, seed nodes are also used to	135	In addition to discovering the network, seed nodes are also used to
123	maintain the network and to connect nodes that otherwise would have	136	maintain the network - all nodes using the same seed node are part of the
124	trouble connecting. They form the backbone of an AnyEvent::MP network.	137	same network. If a network is split into multiple subnets because e.g. the
		138	network link between the parts goes down, then using the same seed nodes
		139	for all nodes ensures that eventually the subnets get merged again.
125		140
126	Seed nodes are expected to be long-running, and at least one seed node	141	Seed nodes are expected to be long-running, and at least one seed node
127	should always be available. They should also be relatively responsive - a	142	should always be available. They should also be relatively responsive - a
128	seed node that blocks for long periods will slow down everybody else.	143	seed node that blocks for long periods will slow down everybody else.
129		144
		145	For small networks, it's best if every node uses the same set of seed
		146	nodes. For large networks, it can be useful to specify "regional" seed
		147	nodes for most nodes in an area, and use all seed nodes as seed nodes for
		148	each other. What's important is that all seed nodes connections form a
		149	complete graph, so that the network cannot split into separate subnets
		150	forever.
		151
		152	Seed nodes are represented by seed IDs.
		153
130	=item seeds - C<host:port>	154	=item seed IDs - C<host:port>
131		155
132	Seeds are transport endpoint(s) (usually a hostname/IP address and a	156	Seed IDs are transport endpoint(s) (usually a hostname/IP address and a
133	TCP port) of nodes that should be used as seed nodes.	157	TCP port) of nodes that should be used as seed nodes.
134		158
135	The nodes listening on those endpoints are expected to be long-running,	159	=item global nodes
136	and at least one of those should always be available. When nodes run out	160
137	of connections (e.g. due to a network error), they try to re-establish	161	An AEMP network needs a discovery service - nodes need to know how to
138	connections to some seednodes again to join the network.	162	connect to other nodes they only know by name. In addition, AEMP offers a
		163	distributed "group database", which maps group names to a list of strings
		164	- for example, to register worker ports.
		165
		166	A network needs at least one global node to work, and allows every node to
		167	be a global node.
		168
		169	Any node that loads the L<AnyEvent::MP::Global> module becomes a global
		170	node and tries to keep connections to all other nodes. So while it can
		171	make sense to make every node "global" in small networks, it usually makes
		172	sense to only make seed nodes into global nodes in large networks (nodes
		173	keep connections to seed nodes and global nodes, so making them the same
		174	reduces overhead).
139		175
140	=back	176	=back
141		177
142	=head1 VARIABLES/FUNCTIONS	178	=head1 VARIABLES/FUNCTIONS
143		179
…		…
145		181
146	=cut	182	=cut
147		183
148	package AnyEvent::MP;	184	package AnyEvent::MP;
149		185
		186	use AnyEvent::MP::Config ();
150	use AnyEvent::MP::Kernel;	187	use AnyEvent::MP::Kernel;
		188	use AnyEvent::MP::Kernel qw(
		189	%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID
		190	add_node load_func
		191
		192	NODE $NODE
		193	configure
		194	node_of port_is_local
		195	snd kil
		196	db_set db_del
		197	db_mon db_family db_keys db_values
		198	);
151		199
152	use common::sense;	200	use common::sense;
153		201
154	use Carp ();	202	use Carp ();
155		203
156	use AE ();	204	use AnyEvent ();
		205	use Guard ();
157		206
158	use base "Exporter";	207	use base "Exporter";
159		208
160	our $VERSION = 1.24;	209	our $VERSION = '2.02'; # also in MP/Config.pm
161		210
162	our @EXPORT = qw(	211	our @EXPORT = qw(
163	NODE $NODE *SELF node_of after
164	configure	212	configure
		213
		214	NODE $NODE
		215	*SELF
		216
		217	node_of port_is_local
		218
		219	snd kil
165	snd rcv mon mon_guard kil psub peval spawn cal	220	port rcv mon mon_guard psub peval spawn cal
166	port	221	db_set db_del db_reg
		222	db_mon db_family db_keys db_values
		223
		224	after
167	);	225	);
168		226
169	our $SELF;	227	our $SELF;
170		228
171	sub _self_die() {	229	sub _self_die() {
…		…
182		240
183	=item $nodeid = node_of $port	241	=item $nodeid = node_of $port
184		242
185	Extracts and returns the node ID from a port ID or a node ID.	243	Extracts and returns the node ID from a port ID or a node ID.
186		244
		245	=item $is_local = port_is_local $port
		246
		247	Returns true iff the port is a local port.
		248
187	=item configure $profile, key => value...	249	=item configure $profile, key => value...
188		250
189	=item configure key => value...	251	=item configure key => value...
190		252
191	Before a node can talk to other nodes on the network (i.e. enter	253	Before a node can talk to other nodes on the network (i.e. enter
…		…
193	to know is its own name, and optionally it should know the addresses of	255	to know is its own name, and optionally it should know the addresses of
194	some other nodes in the network to discover other nodes.	256	some other nodes in the network to discover other nodes.
195		257
196	This function configures a node - it must be called exactly once (or	258	This function configures a node - it must be called exactly once (or
197	never) before calling other AnyEvent::MP functions.	259	never) before calling other AnyEvent::MP functions.
		260
		261	The key/value pairs are basically the same ones as documented for the
		262	F<aemp> command line utility (sans the set/del prefix), with these additions:
		263
		264	=over 4
		265
		266	=item norc => $boolean (default false)
		267
		268	If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
		269	be consulted - all configuration options must be specified in the
		270	C<configure> call.
		271
		272	=item force => $boolean (default false)
		273
		274	IF true, then the values specified in the C<configure> will take
		275	precedence over any values configured via the rc file. The default is for
		276	the rc file to override any options specified in the program.
		277
		278	=back
198		279
199	=over 4	280	=over 4
200		281
201	=item step 1, gathering configuration from profiles	282	=item step 1, gathering configuration from profiles
202		283
…		…
216	That means that the values specified in the profile have highest priority	297	That means that the values specified in the profile have highest priority
217	and the values specified directly via C<configure> have lowest priority,	298	and the values specified directly via C<configure> have lowest priority,
218	and can only be used to specify defaults.	299	and can only be used to specify defaults.
219		300
220	If the profile specifies a node ID, then this will become the node ID of	301	If the profile specifies a node ID, then this will become the node ID of
221	this process. If not, then the profile name will be used as node ID. The	302	this process. If not, then the profile name will be used as node ID, with
222	special node ID of C<anon/> will be replaced by a random node ID.	303	a unique randoms tring (C</%u>) appended.
		304
		305	The node ID can contain some C<%> sequences that are expanded: C<%n>
		306	is expanded to the local nodename, C<%u> is replaced by a random
		307	strign to make the node unique. For example, the F<aemp> commandline
		308	utility uses C<aemp/%n/%u> as nodename, which might expand to
		309	C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
223		310
224	=item step 2, bind listener sockets	311	=item step 2, bind listener sockets
225		312
226	The next step is to look up the binds in the profile, followed by binding	313	The next step is to look up the binds in the profile, followed by binding
227	aemp protocol listeners on all binds specified (it is possible and valid	314	aemp protocol listeners on all binds specified (it is possible and valid
228	to have no binds, meaning that the node cannot be contacted form the	315	to have no binds, meaning that the node cannot be contacted from the
229	outside. This means the node cannot talk to other nodes that also have no	316	outside. This means the node cannot talk to other nodes that also have no
230	binds, but it can still talk to all "normal" nodes).	317	binds, but it can still talk to all "normal" nodes).
231		318
232	If the profile does not specify a binds list, then a default of C<*> is	319	If the profile does not specify a binds list, then a default of C<*> is
233	used, meaning the node will bind on a dynamically-assigned port on every	320	used, meaning the node will bind on a dynamically-assigned port on every
234	local IP address it finds.	321	local IP address it finds.
235		322
236	=item step 3, connect to seed nodes	323	=item step 3, connect to seed nodes
237		324
238	As the last step, the seeds list from the profile is passed to the	325	As the last step, the seed ID list from the profile is passed to the
239	L<AnyEvent::MP::Global> module, which will then use it to keep	326	L<AnyEvent::MP::Global> module, which will then use it to keep
240	connectivity with at least one node at any point in time.	327	connectivity with at least one node at any point in time.
241		328
242	=back	329	=back
243		330
244	Example: become a distributed node using the local node name as profile.	331	Example: become a distributed node using the local node name as profile.
245	This should be the most common form of invocation for "daemon"-type nodes.	332	This should be the most common form of invocation for "daemon"-type nodes.
246		333
247	configure	334	configure
248		335
249	Example: become an anonymous node. This form is often used for commandline	336	Example: become a semi-anonymous node. This form is often used for
250	clients.	337	commandline clients.
251		338
252	configure nodeid => "anon/";	339	configure nodeid => "myscript/%n/%u";
253		340
254	Example: configure a node using a profile called seed, which si suitable	341	Example: configure a node using a profile called seed, which is suitable
255	for a seed node as it binds on all local addresses on a fixed port (4040,	342	for a seed node as it binds on all local addresses on a fixed port (4040,
256	customary for aemp).	343	customary for aemp).
257		344
258	# use the aemp commandline utility	345	# use the aemp commandline utility
259	# aemp profile seed nodeid anon/ binds '*:4040'	346	# aemp profile seed binds '*:4040'
260		347
261	# then use it	348	# then use it
262	configure profile => "seed";	349	configure profile => "seed";
263		350
264	# or simply use aemp from the shell again:	351	# or simply use aemp from the shell again:
…		…
329		416
330	=cut	417	=cut
331		418
332	sub rcv($@);	419	sub rcv($@);
333		420
334	sub _kilme {	421	my $KILME = sub {
335	die "received message on port without callback";	422	(my $tag = substr $_[0], 0, 30) =~ s/([^\x20-\x7e])/./g;
336	}	423	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		424	};
337		425
338	sub port(;&) {	426	sub port(;&) {
339	my $id = "$UNIQ." . $ID++;	427	my $id = $UNIQ . ++$ID;
340	my $port = "$NODE#$id";	428	my $port = "$NODE#$id";
341		429
342	rcv $port, shift \|\| \&_kilme;	430	rcv $port, shift \|\| $KILME;
343		431
344	$port	432	$port
345	}	433	}
346		434
347	=item rcv $local_port, $callback->(@msg)	435	=item rcv $local_port, $callback->(@msg)
…		…
352		440
353	The global C<$SELF> (exported by this module) contains C<$port> while	441	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback. Runtime errors during callback execution will	442	executing the callback. Runtime errors during callback execution will
355	result in the port being C<kil>ed.	443	result in the port being C<kil>ed.
356		444
357	The default callback received all messages not matched by a more specific	445	The default callback receives all messages not matched by a more specific
358	C<tag> match.	446	C<tag> match.
359		447
360	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	448	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
361		449
362	Register (or replace) callbacks to be called on messages starting with the	450	Register (or replace) callbacks to be called on messages starting with the
…		…
397		485
398	sub rcv($@) {	486	sub rcv($@) {
399	my $port = shift;	487	my $port = shift;
400	my ($nodeid, $portid) = split /#/, $port, 2;	488	my ($nodeid, $portid) = split /#/, $port, 2;
401		489
402	$NODE{$nodeid} == $NODE{""}	490	$nodeid eq $NODE
403	or Carp::croak "$port: rcv can only be called on local ports, caught";	491	or Carp::croak "$port: rcv can only be called on local ports, caught";
404		492
405	while (@_) {	493	while (@_) {
406	if (ref $_[0]) {	494	if (ref $_[0]) {
407	if (my $self = $PORT_DATA{$portid}) {	495	if (my $self = $PORT_DATA{$portid}) {
…		…
450	$port	538	$port
451	}	539	}
452		540
453	=item peval $port, $coderef[, @args]	541	=item peval $port, $coderef[, @args]
454		542
455	Evaluates the given C<$codref> within the contetx of C<$port>, that is,	543	Evaluates the given C<$codref> within the context of C<$port>, that is,
456	when the code throews an exception the C<$port> will be killed.	544	when the code throws an exception the C<$port> will be killed.
457		545
458	Any remaining args will be passed to the callback. Any return values will	546	Any remaining args will be passed to the callback. Any return values will
459	be returned to the caller.	547	be returned to the caller.
460		548
461	This is useful when you temporarily want to execute code in the context of	549	This is useful when you temporarily want to execute code in the context of
…		…
492	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	580	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
493	closure is executed, sets up the environment in the same way as in C<rcv>	581	closure is executed, sets up the environment in the same way as in C<rcv>
494	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.	582	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
495		583
496	The effect is basically as if it returned C<< sub { peval $SELF, sub {	584	The effect is basically as if it returned C<< sub { peval $SELF, sub {
497	BLOCK } } >>.	585	BLOCK }, @_ } >>.
498		586
499	This is useful when you register callbacks from C<rcv> callbacks:	587	This is useful when you register callbacks from C<rcv> callbacks:
500		588
501	rcv delayed_reply => sub {	589	rcv delayed_reply => sub {
502	my ($delay, @reply) = @_;	590	my ($delay, @reply) = @_;
…		…
526	$res	614	$res
527	}	615	}
528	}	616	}
529	}	617	}
530		618
		619	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
		620
		621	=item $guard = mon $port # kill $SELF when $port dies
		622
531	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies	623	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
532
533	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
534
535	=item $guard = mon $port # kill $SELF when $port dies
536		624
537	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies	625	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
538		626
539	Monitor the given port and do something when the port is killed or	627	Monitor the given port and do something when the port is killed or
540	messages to it were lost, and optionally return a guard that can be used	628	messages to it were lost, and optionally return a guard that can be used
541	to stop monitoring again.	629	to stop monitoring again.
542		630
		631	The first two forms distinguish between "normal" and "abnormal" kil's:
		632
		633	In the first form (another port given), if the C<$port> is C<kil>'ed with
		634	a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the
		635	same reason. That is, on "normal" kil's nothing happens, while under all
		636	other conditions, the other port is killed with the same reason.
		637
		638	The second form (kill self) is the same as the first form, except that
		639	C<$rvport> defaults to C<$SELF>.
		640
		641	The remaining forms don't distinguish between "normal" and "abnormal" kil's
		642	- it's up to the callback or receiver to check whether the C<@reason> is
		643	empty and act accordingly.
		644
543	In the first form (callback), the callback is simply called with any	645	In the third form (callback), the callback is simply called with any
544	number of C<@reason> elements (no @reason means that the port was deleted	646	number of C<@reason> elements (empty @reason means that the port was deleted
545	"normally"). Note also that I<< the callback B<must> never die >>, so use	647	"normally"). Note also that I<< the callback B<must> never die >>, so use
546	C<eval> if unsure.	648	C<eval> if unsure.
547		649
548	In the second form (another port given), the other port (C<$rcvport>)
549	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
550	"normal" kils nothing happens, while under all other conditions, the other
551	port is killed with the same reason.
552
553	The third form (kill self) is the same as the second form, except that
554	C<$rvport> defaults to C<$SELF>.
555
556	In the last form (message), a message of the form C<@msg, @reason> will be	650	In the last form (message), a message of the form C<$rcvport, @msg,
557	C<snd>.	651	@reason> will be C<snd>.
558		652
559	Monitoring-actions are one-shot: once messages are lost (and a monitoring	653	Monitoring-actions are one-shot: once messages are lost (and a monitoring
560	alert was raised), they are removed and will not trigger again.	654	alert was raised), they are removed and will not trigger again, even if it
		655	turns out that the port is still alive.
561		656
562	As a rule of thumb, monitoring requests should always monitor a port from	657	As a rule of thumb, monitoring requests should always monitor a remote
563	a local port (or callback). The reason is that kill messages might get	658	port locally (using a local C<$rcvport> or a callback). The reason is that
564	lost, just like any other message. Another less obvious reason is that	659	kill messages might get lost, just like any other message. Another less
565	even monitoring requests can get lost (for example, when the connection	660	obvious reason is that even monitoring requests can get lost (for example,
566	to the other node goes down permanently). When monitoring a port locally	661	when the connection to the other node goes down permanently). When
567	these problems do not exist.	662	monitoring a port locally these problems do not exist.
568		663
569	C<mon> effectively guarantees that, in the absence of hardware failures,	664	C<mon> effectively guarantees that, in the absence of hardware failures,
570	after starting the monitor, either all messages sent to the port will	665	after starting the monitor, either all messages sent to the port will
571	arrive, or the monitoring action will be invoked after possible message	666	arrive, or the monitoring action will be invoked after possible message
572	loss has been detected. No messages will be lost "in between" (after	667	loss has been detected. No messages will be lost "in between" (after
…		…
617	}	712	}
618		713
619	$node->monitor ($port, $cb);	714	$node->monitor ($port, $cb);
620		715
621	defined wantarray	716	defined wantarray
622	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	717	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
623	}	718	}
624		719
625	=item $guard = mon_guard $port, $ref, $ref...	720	=item $guard = mon_guard $port, $ref, $ref...
626		721
627	Monitors the given C<$port> and keeps the passed references. When the port	722	Monitors the given C<$port> and keeps the passed references. When the port
…		…
650		745
651	=item kil $port[, @reason]	746	=item kil $port[, @reason]
652		747
653	Kill the specified port with the given C<@reason>.	748	Kill the specified port with the given C<@reason>.
654		749
655	If no C<@reason> is specified, then the port is killed "normally" (ports	750	If no C<@reason> is specified, then the port is killed "normally" -
656	monitoring other ports will not necessarily die because a port dies	751	monitor callback will be invoked, but the kil will not cause linked ports
657	"normally").	752	(C<mon $mport, $lport> form) to get killed.
658		753
659	Otherwise, linked ports get killed with the same reason (second form of	754	If a C<@reason> is specified, then linked ports (C<mon $mport, $lport>
660	C<mon>, see above).	755	form) get killed with the same reason.
661		756
662	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	757	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
663	will be reported as reason C<< die => $@ >>.	758	will be reported as reason C<< die => $@ >>.
664		759
665	Transport/communication errors are reported as C<< transport_error =>	760	Transport/communication errors are reported as C<< transport_error =>
666	$message >>.	761	$message >>.
667		762
668	=cut	763	Common idioms:
		764
		765	# silently remove yourself, do not kill linked ports
		766	kil $SELF;
		767
		768	# report a failure in some detail
		769	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		770
		771	# do not waste much time with killing, just die when something goes wrong
		772	open my $fh, "<file"
		773	or die "file: $!";
669		774
670	=item $port = spawn $node, $initfunc[, @initdata]	775	=item $port = spawn $node, $initfunc[, @initdata]
671		776
672	Creates a port on the node C<$node> (which can also be a port ID, in which	777	Creates a port on the node C<$node> (which can also be a port ID, in which
673	case it's the node where that port resides).	778	case it's the node where that port resides).
…		…
731	}	836	}
732		837
733	sub spawn(@) {	838	sub spawn(@) {
734	my ($nodeid, undef) = split /#/, shift, 2;	839	my ($nodeid, undef) = split /#/, shift, 2;
735		840
736	my $id = "$RUNIQ." . $ID++;	841	my $id = $RUNIQ . ++$ID;
737		842
738	$_[0] =~ /::/	843	$_[0] =~ /::/
739	or Carp::croak "spawn init function must be a fully-qualified name, caught";	844	or Carp::croak "spawn init function must be a fully-qualified name, caught";
740		845
741	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	846	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
742		847
743	"$nodeid#$id"	848	"$nodeid#$id"
744	}	849	}
		850
745		851
746	=item after $timeout, @msg	852	=item after $timeout, @msg
747		853
748	=item after $timeout, $callback	854	=item after $timeout, $callback
749		855
…		…
764	ref $action[0]	870	ref $action[0]
765	? $action[0]()	871	? $action[0]()
766	: snd @action;	872	: snd @action;
767	};	873	};
768	}	874	}
		875
		876	#=item $cb2 = timeout $seconds, $cb[, @args]
769		877
770	=item cal $port, @msg, $callback[, $timeout]	878	=item cal $port, @msg, $callback[, $timeout]
771		879
772	A simple form of RPC - sends a message to the given C<$port> with the	880	A simple form of RPC - sends a message to the given C<$port> with the
773	given contents (C<@msg>), but adds a reply port to the message.	881	given contents (C<@msg>), but adds a reply port to the message.
…		…
819	$port	927	$port
820	}	928	}
821		929
822	=back	930	=back
823		931
		932	=head1 DISTRIBUTED DATABASE
		933
		934	AnyEvent::MP comes with a simple distributed database. The database will
		935	be mirrored asynchronously on all global nodes. Other nodes bind to one
		936	of the global nodes for their needs. Every node has a "local database"
		937	which contains all the values that are set locally. All local databases
		938	are merged together to form the global database, which can be queried.
		939
		940	The database structure is that of a two-level hash - the database hash
		941	contains hashes which contain values, similarly to a perl hash of hashes,
		942	i.e.:
		943
		944	$DATABASE{$family}{$subkey} = $value
		945
		946	The top level hash key is called "family", and the second-level hash key
		947	is called "subkey" or simply "key".
		948
		949	The family must be alphanumeric, i.e. start with a letter and consist
		950	of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
		951	pretty much like Perl module names.
		952
		953	As the family namespace is global, it is recommended to prefix family names
		954	with the name of the application or module using it.
		955
		956	The subkeys must be non-empty strings, with no further restrictions.
		957
		958	The values should preferably be strings, but other perl scalars should
		959	work as well (such as C<undef>, arrays and hashes).
		960
		961	Every database entry is owned by one node - adding the same family/subkey
		962	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
		963	but the result might be nondeterministic, i.e. the key might have
		964	different values on different nodes.
		965
		966	Different subkeys in the same family can be owned by different nodes
		967	without problems, and in fact, this is the common method to create worker
		968	pools. For example, a worker port for image scaling might do this:
		969
		970	db_set my_image_scalers => $port;
		971
		972	And clients looking for an image scaler will want to get the
		973	C<my_image_scalers> keys from time to time:
		974
		975	db_keys my_image_scalers => sub {
		976	@ports = @{ $_[0] };
		977	};
		978
		979	Or better yet, they want to monitor the database family, so they always
		980	have a reasonable up-to-date copy:
		981
		982	db_mon my_image_scalers => sub {
		983	@ports = keys %{ $_[0] };
		984	};
		985
		986	In general, you can set or delete single subkeys, but query and monitor
		987	whole families only.
		988
		989	If you feel the need to monitor or query a single subkey, try giving it
		990	it's own family.
		991
		992	=over
		993
		994	=item $guard = db_set $family => $subkey [=> $value]
		995
		996	Sets (or replaces) a key to the database - if C<$value> is omitted,
		997	C<undef> is used instead.
		998
		999	When called in non-void context, C<db_set> returns a guard that
		1000	automatically calls C<db_del> when it is destroyed.
		1001
		1002	=item db_del $family => $subkey...
		1003
		1004	Deletes one or more subkeys from the database family.
		1005
		1006	=item $guard = db_reg $family => $port => $value
		1007
		1008	=item $guard = db_reg $family => $port
		1009
		1010	=item $guard = db_reg $family
		1011
		1012	Registers a port in the given family and optionally returns a guard to
		1013	remove it.
		1014
		1015	This function basically does the same as:
		1016
		1017	db_set $family => $port => $value
		1018
		1019	Except that the port is monitored and automatically removed from the
		1020	database family when it is kil'ed.
		1021
		1022	If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
		1023	C<$SELF> is used.
		1024
		1025	This function is most useful to register a port in some port group (which
		1026	is just another name for a database family), and have it removed when the
		1027	port is gone. This works best when the port is a local port.
		1028
		1029	=cut
		1030
		1031	sub db_reg($$;$) {
		1032	my $family = shift;
		1033	my $port = @_ ? shift : $SELF;
		1034
		1035	my $clr = sub { db_del $family => $port };
		1036	mon $port, $clr;
		1037
		1038	db_set $family => $port => $_[0];
		1039
		1040	defined wantarray
		1041	and &Guard::guard ($clr)
		1042	}
		1043
		1044	=item db_family $family => $cb->(\%familyhash)
		1045
		1046	Queries the named database C<$family> and call the callback with the
		1047	family represented as a hash. You can keep and freely modify the hash.
		1048
		1049	=item db_keys $family => $cb->(\@keys)
		1050
		1051	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		1052	them as array reference to the callback.
		1053
		1054	=item db_values $family => $cb->(\@values)
		1055
		1056	Same as C<db_family>, except it only queries the family I<values> and passes them
		1057	as array reference to the callback.
		1058
		1059	=item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
		1060
		1061	Creates a monitor on the given database family. Each time a key is
		1062	set or is deleted the callback is called with a hash containing the
		1063	database family and three lists of added, changed and deleted subkeys,
		1064	respectively. If no keys have changed then the array reference might be
		1065	C<undef> or even missing.
		1066
		1067	If not called in void context, a guard object is returned that, when
		1068	destroyed, stops the monitor.
		1069
		1070	The family hash reference and the key arrays belong to AnyEvent::MP and
		1071	B<must not be modified or stored> by the callback. When in doubt, make a
		1072	copy.
		1073
		1074	As soon as possible after the monitoring starts, the callback will be
		1075	called with the intiial contents of the family, even if it is empty,
		1076	i.e. there will always be a timely call to the callback with the current
		1077	contents.
		1078
		1079	It is possible that the callback is called with a change event even though
		1080	the subkey is already present and the value has not changed.
		1081
		1082	The monitoring stops when the guard object is destroyed.
		1083
		1084	Example: on every change to the family "mygroup", print out all keys.
		1085
		1086	my $guard = db_mon mygroup => sub {
		1087	my ($family, $a, $c, $d) = @_;
		1088	print "mygroup members: ", (join " ", keys %$family), "\n";
		1089	};
		1090
		1091	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1092
		1093	my $guard; $guard = db_mon My::Module::workers => sub {
		1094	my ($family, $a, $c, $d) = @_;
		1095	return unless %$family;
		1096	undef $guard;
		1097	print "My::Module::workers now nonempty\n";
		1098	};
		1099
		1100	Example: print all changes to the family "AnyEvent::Fantasy::Module".
		1101
		1102	my $guard = db_mon AnyEvent::Fantasy::Module => sub {
		1103	my ($family, $a, $c, $d) = @_;
		1104
		1105	print "+$_=$family->{$_}\n" for @$a;
		1106	print "*$_=$family->{$_}\n" for @$c;
		1107	print "-$_=$family->{$_}\n" for @$d;
		1108	};
		1109
		1110	=cut
		1111
		1112	=back
		1113
824	=head1 AnyEvent::MP vs. Distributed Erlang	1114	=head1 AnyEvent::MP vs. Distributed Erlang
825		1115
826	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1116	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
827	== aemp node, Erlang process == aemp port), so many of the documents and	1117	== aemp node, Erlang process == aemp port), so many of the documents and
828	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	1118	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
…		…
859	ports being the special case/exception, where transport errors cannot	1149	ports being the special case/exception, where transport errors cannot
860	occur.	1150	occur.
861		1151
862	=item * Erlang uses processes and a mailbox, AEMP does not queue.	1152	=item * Erlang uses processes and a mailbox, AEMP does not queue.
863		1153
864	Erlang uses processes that selectively receive messages, and therefore	1154	Erlang uses processes that selectively receive messages out of order, and
865	needs a queue. AEMP is event based, queuing messages would serve no	1155	therefore needs a queue. AEMP is event based, queuing messages would serve
866	useful purpose. For the same reason the pattern-matching abilities of	1156	no useful purpose. For the same reason the pattern-matching abilities
867	AnyEvent::MP are more limited, as there is little need to be able to	1157	of AnyEvent::MP are more limited, as there is little need to be able to
868	filter messages without dequeuing them.	1158	filter messages without dequeuing them.
869		1159
870	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	1160	This is not a philosophical difference, but simply stems from AnyEvent::MP
		1161	being event-based, while Erlang is process-based.
		1162
		1163	You can have a look at L<Coro::MP> for a more Erlang-like process model on
		1164	top of AEMP and Coro threads.
871		1165
872	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	1166	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
873		1167
874	Sending messages in Erlang is synchronous and blocks the process (and	1168	Sending messages in Erlang is synchronous and blocks the process until
		1169	a connection has been established and the message sent (and so does not
875	so does not need a queue that can overflow). AEMP sends are immediate,	1170	need a queue that can overflow). AEMP sends return immediately, connection
876	connection establishment is handled in the background.	1171	establishment is handled in the background.
877		1172
878	=item * Erlang suffers from silent message loss, AEMP does not.	1173	=item * Erlang suffers from silent message loss, AEMP does not.
879		1174
880	Erlang implements few guarantees on messages delivery - messages can get	1175	Erlang implements few guarantees on messages delivery - messages can get
881	lost without any of the processes realising it (i.e. you send messages a,	1176	lost without any of the processes realising it (i.e. you send messages a,
882	b, and c, and the other side only receives messages a and c).	1177	b, and c, and the other side only receives messages a and c).
883		1178
884	AEMP guarantees correct ordering, and the guarantee that after one message	1179	AEMP guarantees (modulo hardware errors) correct ordering, and the
885	is lost, all following ones sent to the same port are lost as well, until	1180	guarantee that after one message is lost, all following ones sent to the
886	monitoring raises an error, so there are no silent "holes" in the message	1181	same port are lost as well, until monitoring raises an error, so there are
887	sequence.	1182	no silent "holes" in the message sequence.
		1183
		1184	If you want your software to be very reliable, you have to cope with
		1185	corrupted and even out-of-order messages in both Erlang and AEMP. AEMP
		1186	simply tries to work better in common error cases, such as when a network
		1187	link goes down.
888		1188
889	=item * Erlang can send messages to the wrong port, AEMP does not.	1189	=item * Erlang can send messages to the wrong port, AEMP does not.
890		1190
891	In Erlang it is quite likely that a node that restarts reuses a process ID	1191	In Erlang it is quite likely that a node that restarts reuses an Erlang
892	known to other nodes for a completely different process, causing messages	1192	process ID known to other nodes for a completely different process,
893	destined for that process to end up in an unrelated process.	1193	causing messages destined for that process to end up in an unrelated
		1194	process.
894		1195
895	AEMP never reuses port IDs, so old messages or old port IDs floating	1196	AEMP does not reuse port IDs, so old messages or old port IDs floating
896	around in the network will not be sent to an unrelated port.	1197	around in the network will not be sent to an unrelated port.
897		1198
898	=item * Erlang uses unprotected connections, AEMP uses secure	1199	=item * Erlang uses unprotected connections, AEMP uses secure
899	authentication and can use TLS.	1200	authentication and can use TLS.
900		1201
…		…
903		1204
904	=item * The AEMP protocol is optimised for both text-based and binary	1205	=item * The AEMP protocol is optimised for both text-based and binary
905	communications.	1206	communications.
906		1207
907	The AEMP protocol, unlike the Erlang protocol, supports both programming	1208	The AEMP protocol, unlike the Erlang protocol, supports both programming
908	language independent text-only protocols (good for debugging) and binary,	1209	language independent text-only protocols (good for debugging), and binary,
909	language-specific serialisers (e.g. Storable). By default, unless TLS is	1210	language-specific serialisers (e.g. Storable). By default, unless TLS is
910	used, the protocol is actually completely text-based.	1211	used, the protocol is actually completely text-based.
911		1212
912	It has also been carefully designed to be implementable in other languages	1213	It has also been carefully designed to be implementable in other languages
913	with a minimum of work while gracefully degrading functionality to make the	1214	with a minimum of work while gracefully degrading functionality to make the
914	protocol simple.	1215	protocol simple.
915		1216
916	=item * AEMP has more flexible monitoring options than Erlang.	1217	=item * AEMP has more flexible monitoring options than Erlang.
917		1218
918	In Erlang, you can chose to receive I<all> exit signals as messages	1219	In Erlang, you can chose to receive I<all> exit signals as messages or
919	or I<none>, there is no in-between, so monitoring single processes is	1220	I<none>, there is no in-between, so monitoring single Erlang processes is
920	difficult to implement. Monitoring in AEMP is more flexible than in	1221	difficult to implement.
921	Erlang, as one can choose between automatic kill, exit message or callback	1222
922	on a per-process basis.	1223	Monitoring in AEMP is more flexible than in Erlang, as one can choose
		1224	between automatic kill, exit message or callback on a per-port basis.
923		1225
924	=item * Erlang tries to hide remote/local connections, AEMP does not.	1226	=item * Erlang tries to hide remote/local connections, AEMP does not.
925		1227
926	Monitoring in Erlang is not an indicator of process death/crashes, in the	1228	Monitoring in Erlang is not an indicator of process death/crashes, in the
927	same way as linking is (except linking is unreliable in Erlang).	1229	same way as linking is (except linking is unreliable in Erlang).
…		…
949	overhead, as well as having to keep a proxy object everywhere.	1251	overhead, as well as having to keep a proxy object everywhere.
950		1252
951	Strings can easily be printed, easily serialised etc. and need no special	1253	Strings can easily be printed, easily serialised etc. and need no special
952	procedures to be "valid".	1254	procedures to be "valid".
953		1255
954	And as a result, a miniport consists of a single closure stored in a	1256	And as a result, a port with just a default receiver consists of a single
955	global hash - it can't become much cheaper.	1257	code reference stored in a global hash - it can't become much cheaper.
956		1258
957	=item Why favour JSON, why not a real serialising format such as Storable?	1259	=item Why favour JSON, why not a real serialising format such as Storable?
958		1260
959	In fact, any AnyEvent::MP node will happily accept Storable as framing	1261	In fact, any AnyEvent::MP node will happily accept Storable as framing
960	format, but currently there is no way to make a node use Storable by	1262	format, but currently there is no way to make a node use Storable by
…		…
970	Keeping your messages simple, concentrating on data structures rather than	1272	Keeping your messages simple, concentrating on data structures rather than
971	objects, will keep your messages clean, tidy and efficient.	1273	objects, will keep your messages clean, tidy and efficient.
972		1274
973	=back	1275	=back
974		1276
		1277	=head1 PORTING FROM AnyEvent::MP VERSION 1.X
		1278
		1279	AEMP version 2 has a few major incompatible changes compared to version 1:
		1280
		1281	=over 4
		1282
		1283	=item AnyEvent::MP::Global no longer has group management functions.
		1284
		1285	At least not officially - the grp_* functions are still exported and might
		1286	work, but they will be removed in some later release.
		1287
		1288	AnyEvent::MP now comes with a distributed database that is more
		1289	powerful. Its database families map closely to port groups, but the API
		1290	has changed (the functions are also now exported by AnyEvent::MP). Here is
		1291	a rough porting guide:
		1292
		1293	grp_reg $group, $port # old
		1294	db_reg $group, $port # new
		1295
		1296	$list = grp_get $group # old
		1297	db_keys $group, sub { my $list = shift } # new
		1298
		1299	grp_mon $group, $cb->(\@ports, $add, $del) # old
		1300	db_mon $group, $cb->(\%ports, $add, $change, $del) # new
		1301
		1302	C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is
		1303	no longer instant, because the local node might not have a copy of the
		1304	group. You can either modify your code to allow for a callback, or use
		1305	C<db_mon> to keep an updated copy of the group:
		1306
		1307	my $local_group_copy;
		1308	db_mon $group => sub { $local_group_copy = $_[0] };
		1309
		1310	# now "keys %$local_group_copy" always returns the most up-to-date
		1311	# list of ports in the group.
		1312
		1313	C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
		1314	passes a hash as first argument, and an extra C<$chg> argument that can be
		1315	ignored:
		1316
		1317	db_mon $group => sub {
		1318	my ($ports, $add, $chg, $del) = @_;
		1319	$ports = [keys %$ports];
		1320
		1321	# now $ports, $add and $del are the same as
		1322	# were originally passed by grp_mon.
		1323	...
		1324	};
		1325
		1326	=item Nodes not longer connect to all other nodes.
		1327
		1328	In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
		1329	module, which in turn would create connections to all other nodes in the
		1330	network (helped by the seed nodes).
		1331
		1332	In version 2.x, global nodes still connect to all other global nodes, but
		1333	other nodes don't - now every node either is a global node itself, or
		1334	attaches itself to another global node.
		1335
		1336	If a node isn't a global node itself, then it attaches itself to one
		1337	of its seed nodes. If that seed node isn't a global node yet, it will
		1338	automatically be upgraded to a global node.
		1339
		1340	So in many cases, nothing needs to be changed - one just has to make sure
		1341	that all seed nodes are meshed together with the other seed nodes (as with
		1342	AEMP 1.x), and other nodes specify them as seed nodes. This is most easily
		1343	achieved by specifying the same set of seed nodes for all nodes in the
		1344	network.
		1345
		1346	Not opening a connection to every other node is usually an advantage,
		1347	except when you need the lower latency of an already established
		1348	connection. To ensure a node establishes a connection to another node,
		1349	you can monitor the node port (C<mon $node, ...>), which will attempt to
		1350	create the connection (and notify you when the connection fails).
		1351
		1352	=item Listener-less nodes (nodes without binds) are gone.
		1353
		1354	And are not coming back, at least not in their old form. If no C<binds>
		1355	are specified for a node, AnyEvent::MP assumes a default of C<:>.
		1356
		1357	There are vague plans to implement some form of routing domains, which
		1358	might or might not bring back listener-less nodes, but don't count on it.
		1359
		1360	The fact that most connections are now optional somewhat mitigates this,
		1361	as a node can be effectively unreachable from the outside without any
		1362	problems, as long as it isn't a global node and only reaches out to other
		1363	nodes (as opposed to being contacted from other nodes).
		1364
		1365	=item $AnyEvent::MP::Kernel::WARN has gone.
		1366
		1367	AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
		1368	uses this, and so should your programs.
		1369
		1370	Every module now documents what kinds of messages it generates, with
		1371	AnyEvent::MP acting as a catch all.
		1372
		1373	On the positive side, this means that instead of setting
		1374	C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> -
		1375	much less to type.
		1376
		1377	=back
		1378
		1379	=head1 LOGGING
		1380
		1381	AnyEvent::MP does not normally log anything by itself, but since it is the
		1382	root of the context hierarchy for AnyEvent::MP modules, it will receive
		1383	all log messages by submodules.
		1384
975	=head1 SEE ALSO	1385	=head1 SEE ALSO
976		1386
977	L<AnyEvent::MP::Intro> - a gentle introduction.	1387	L<AnyEvent::MP::Intro> - a gentle introduction.
978		1388
979	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1389	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
980		1390
981	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	1391	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
982	your applications.	1392	your applications.
983		1393
984	L<AnyEvent::MP::DataConn> - establish data connections between nodes.	1394	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
985		1395
986	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from	1396	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC vs. Revision 1.153 by root, Sat Nov 2 01:30:49 2019 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC vs.
Revision 1.153 by root, Sat Nov 2 01:30:49 2019 UTC