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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.104 by root, Fri Nov 6 17:47:20 2009 UTC vs.
Revision 1.121 by root, Tue Feb 28 18:37:24 2012 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 $localport, $cb->(@msg) # callback is invoked on death
…		…
78		78
79	Ports allow you to register C<rcv> handlers that can match all or just	79	Ports allow you to register C<rcv> handlers that can match all or just
80	some messages. Messages send to ports will not be queued, regardless of	80	some messages. Messages send to ports will not be queued, regardless of
81	anything was listening for them or not.	81	anything was listening for them or not.
82		82
		83	Ports are represented by (printable) strings called "port IDs".
		84
83	=item port ID - C<nodeid#portname>	85	=item port ID - C<nodeid#portname>
84		86
85	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as	87	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format).	88	separator, and a port name (a printable string of unspecified format).
87		89
…		…
91	which enables nodes to manage each other remotely, and to create new	93	which enables nodes to manage each other remotely, and to create new
92	ports.	94	ports.
93		95
94	Nodes are either public (have one or more listening ports) or private	96	Nodes are either public (have one or more listening ports) or private
95	(no listening ports). Private nodes cannot talk to other private nodes	97	(no listening ports). Private nodes cannot talk to other private nodes
96	currently.	98	currently, but all nodes can talk to public nodes.
97		99
		100	Nodes is represented by (printable) strings called "node IDs".
		101
98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>	102	=item node ID - C<[A-Za-z0-9_\-.:]*>
99		103
100	A node ID is a string that uniquely identifies the node within a	104	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	105	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	106	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
103	doesn't interpret node IDs in any way.	107	doesn't interpret node IDs in any way except to uniquely identify a node.
104		108
105	=item binds - C<ip:port>	109	=item binds - C<ip:port>
106		110
107	Nodes can only talk to each other by creating some kind of connection to	111	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	112	each other. To do this, nodes should listen on one or more local transport
		113	endpoints - binds.
		114
109	endpoints - binds. Currently, only standard C<ip:port> specifications can	115	Currently, only standard C<ip:port> specifications can be used, which
110	be used, which specify TCP ports to listen on.	116	specify TCP ports to listen on. So a bind is basically just a tcp socket
		117	in listening mode thta accepts conenctions form other nodes.
111		118
112	=item seed nodes	119	=item seed nodes
113		120
114	When a node starts, it knows nothing about the network. To teach the node	121	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	122	needs to connect to at least one other node that is already in the
116	network. This node is called a seed.	123	network. These other nodes are called "seed nodes".
117		124
118	Apart from the fact that other nodes know them as seed nodes and they have	125	Seed nodes themselves are not special - they are seed nodes only because
119	to have fixed listening addresses, seed nodes are perfectly normal nodes -	126	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.	127	node for other nodes, and eahc node cna use a different set of seed nodes.
121		128
122	In addition to discovering the network, seed nodes are also used to	129	In addition to discovering the network, seed nodes are also used to
123	maintain the network and to connect nodes that otherwise would have	130	maintain the network - all nodes using the same seed node form are part of
124	trouble connecting. They form the backbone of an AnyEvent::MP network.	131	the same network. If a network is split into multiple subnets because e.g.
		132	the network link between the parts goes down, then using the same seed
		133	nodes for all nodes ensures that eventually the subnets get merged again.
125		134
126	Seed nodes are expected to be long-running, and at least one seed node	135	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	136	should always be available. They should also be relatively responsive - a
128	seed node that blocks for long periods will slow down everybody else.	137	seed node that blocks for long periods will slow down everybody else.
129		138
		139	For small networks, it's best if every node uses the same set of seed
		140	nodes. For large networks, it can be useful to specify "regional" seed
		141	nodes for most nodes in an area, and use all seed nodes as seed nodes for
		142	each other. What's important is that all seed nodes connections form a
		143	complete graph, so that the network cannot split into separate subnets
		144	forever.
		145
		146	Seed nodes are represented by seed IDs.
		147
130	=item seeds - C<host:port>	148	=item seed IDs - C<host:port>
131		149
132	Seeds are transport endpoint(s) (usually a hostname/IP address and a	150	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.	151	TCP port) of nodes that should be used as seed nodes.
134		152
135	The nodes listening on those endpoints are expected to be long-running,	153	=item global nodes
136	and at least one of those should always be available. When nodes run out	154
137	of connections (e.g. due to a network error), they try to re-establish	155	An AEMP network needs a discovery service - nodes need to know how to
138	connections to some seednodes again to join the network.	156	connect to other nodes they only know by name. In addition, AEMP offers a
		157	distributed "group database", which maps group names to a list of strings
		158	- for example, to register worker ports.
		159
		160	A network needs at least one global node to work, and allows every node to
		161	be a global node.
		162
		163	Any node that loads the L<AnyEvent::MP::Global> module becomes a global
		164	node and tries to keep connections to all other nodes. So while it can
		165	make sense to make every node "global" in small networks, it usually makes
		166	sense to only make seed nodes into global nodes in large networks (nodes
		167	keep connections to seed nodes and global nodes, so makign them the same
		168	reduces overhead).
139		169
140	=back	170	=back
141		171
142	=head1 VARIABLES/FUNCTIONS	172	=head1 VARIABLES/FUNCTIONS
143		173
…		…
145		175
146	=cut	176	=cut
147		177
148	package AnyEvent::MP;	178	package AnyEvent::MP;
149		179
		180	use AnyEvent::MP::Config ();
150	use AnyEvent::MP::Kernel;	181	use AnyEvent::MP::Kernel;
		182	use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID);
151		183
152	use common::sense;	184	use common::sense;
153		185
154	use Carp ();	186	use Carp ();
155		187
156	use AE ();	188	use AE ();
157		189
158	use base "Exporter";	190	use base "Exporter";
159		191
160	our $VERSION = 1.23;	192	our $VERSION = $AnyEvent::MP::Config::VERSION;
161		193
162	our @EXPORT = qw(	194	our @EXPORT = qw(
163	NODE $NODE *SELF node_of after	195	NODE $NODE *SELF node_of after
164	configure	196	configure
165	snd rcv mon mon_guard kil psub peval spawn cal	197	snd rcv mon mon_guard kil psub peval spawn cal
…		…
194	some other nodes in the network to discover other nodes.	226	some other nodes in the network to discover other nodes.
195		227
196	This function configures a node - it must be called exactly once (or	228	This function configures a node - it must be called exactly once (or
197	never) before calling other AnyEvent::MP functions.	229	never) before calling other AnyEvent::MP functions.
198		230
		231	The key/value pairs are basically the same ones as documented for the
		232	F<aemp> command line utility (sans the set/del prefix), with two additions:
		233
		234	=over 4
		235
		236	=item norc => $boolean (default false)
		237
		238	If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
		239	be consulted - all configuraiton options must be specified in the
		240	C<configure> call.
		241
		242	=item force => $boolean (default false)
		243
		244	IF true, then the values specified in the C<configure> will take
		245	precedence over any values configured via the rc file. The default is for
		246	the rc file to override any options specified in the program.
		247
		248	=back
		249
199	=over 4	250	=over 4
200		251
201	=item step 1, gathering configuration from profiles	252	=item step 1, gathering configuration from profiles
202		253
203	The function first looks up a profile in the aemp configuration (see the	254	The function first looks up a profile in the aemp configuration (see the
…		…
233	used, meaning the node will bind on a dynamically-assigned port on every	284	used, meaning the node will bind on a dynamically-assigned port on every
234	local IP address it finds.	285	local IP address it finds.
235		286
236	=item step 3, connect to seed nodes	287	=item step 3, connect to seed nodes
237		288
238	As the last step, the seeds list from the profile is passed to the	289	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	290	L<AnyEvent::MP::Global> module, which will then use it to keep
240	connectivity with at least one node at any point in time.	291	connectivity with at least one node at any point in time.
241		292
242	=back	293	=back
243		294
…		…
249	Example: become an anonymous node. This form is often used for commandline	300	Example: become an anonymous node. This form is often used for commandline
250	clients.	301	clients.
251		302
252	configure nodeid => "anon/";	303	configure nodeid => "anon/";
253		304
254	Example: configure a node using a profile called seed, which si suitable	305	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,	306	for a seed node as it binds on all local addresses on a fixed port (4040,
256	customary for aemp).	307	customary for aemp).
257		308
258	# use the aemp commandline utility	309	# use the aemp commandline utility
259	# aemp profile seed nodeid anon/ binds '*:4040'	310	# aemp profile seed nodeid anon/ binds '*:4040'
…		…
334	sub _kilme {	385	sub _kilme {
335	die "received message on port without callback";	386	die "received message on port without callback";
336	}	387	}
337		388
338	sub port(;&) {	389	sub port(;&) {
339	my $id = "$UNIQ." . $ID++;	390	my $id = "$UNIQ." . ++$ID;
340	my $port = "$NODE#$id";	391	my $port = "$NODE#$id";
341		392
342	rcv $port, shift \|\| \&_kilme;	393	rcv $port, shift \|\| \&_kilme;
343		394
344	$port	395	$port
…		…
492	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	543	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>	544	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.	545	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
495		546
496	The effect is basically as if it returned C<< sub { peval $SELF, sub {	547	The effect is basically as if it returned C<< sub { peval $SELF, sub {
497	BLOCK } } >>.	548	BLOCK }, @_ } >>.
498		549
499	This is useful when you register callbacks from C<rcv> callbacks:	550	This is useful when you register callbacks from C<rcv> callbacks:
500		551
501	rcv delayed_reply => sub {	552	rcv delayed_reply => sub {
502	my ($delay, @reply) = @_;	553	my ($delay, @reply) = @_;
…		…
650		701
651	=item kil $port[, @reason]	702	=item kil $port[, @reason]
652		703
653	Kill the specified port with the given C<@reason>.	704	Kill the specified port with the given C<@reason>.
654		705
655	If no C<@reason> is specified, then the port is killed "normally" (ports	706	If no C<@reason> is specified, then the port is killed "normally" -
656	monitoring other ports will not necessarily die because a port dies	707	monitor callback will be invoked, but the kil will not cause linked ports
657	"normally").	708	(C<mon $mport, $lport> form) to get killed.
658		709
659	Otherwise, linked ports get killed with the same reason (second form of	710	If a C<@reason> is specified, then linked ports (C<mon $mport, $lport>
660	C<mon>, see above).	711	form) get killed with the same reason.
661		712
662	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	713	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
663	will be reported as reason C<< die => $@ >>.	714	will be reported as reason C<< die => $@ >>.
664		715
665	Transport/communication errors are reported as C<< transport_error =>	716	Transport/communication errors are reported as C<< transport_error =>
…		…
731	}	782	}
732		783
733	sub spawn(@) {	784	sub spawn(@) {
734	my ($nodeid, undef) = split /#/, shift, 2;	785	my ($nodeid, undef) = split /#/, shift, 2;
735		786
736	my $id = "$RUNIQ." . $ID++;	787	my $id = "$RUNIQ." . ++$ID;
737		788
738	$_[0] =~ /::/	789	$_[0] =~ /::/
739	or Carp::croak "spawn init function must be a fully-qualified name, caught";	790	or Carp::croak "spawn init function must be a fully-qualified name, caught";
740		791
741	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	792	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
742		793
743	"$nodeid#$id"	794	"$nodeid#$id"
744	}	795	}
		796
745		797
746	=item after $timeout, @msg	798	=item after $timeout, @msg
747		799
748	=item after $timeout, $callback	800	=item after $timeout, $callback
749		801
…		…
859	ports being the special case/exception, where transport errors cannot	911	ports being the special case/exception, where transport errors cannot
860	occur.	912	occur.
861		913
862	=item * Erlang uses processes and a mailbox, AEMP does not queue.	914	=item * Erlang uses processes and a mailbox, AEMP does not queue.
863		915
864	Erlang uses processes that selectively receive messages, and therefore	916	Erlang uses processes that selectively receive messages out of order, and
865	needs a queue. AEMP is event based, queuing messages would serve no	917	therefore needs a queue. AEMP is event based, queuing messages would serve
866	useful purpose. For the same reason the pattern-matching abilities of	918	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	919	of AnyEvent::MP are more limited, as there is little need to be able to
868	filter messages without dequeuing them.	920	filter messages without dequeuing them.
869		921
870	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	922	This is not a philosophical difference, but simply stems from AnyEvent::MP
		923	being event-based, while Erlang is process-based.
		924
		925	You cna have a look at L<Coro::MP> for a more Erlang-like process model on
		926	top of AEMP and Coro threads.
871		927
872	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	928	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
873		929
874	Sending messages in Erlang is synchronous and blocks the process (and	930	Sending messages in Erlang is synchronous and blocks the process until
		931	a conenction 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,	932	need a queue that can overflow). AEMP sends return immediately, connection
876	connection establishment is handled in the background.	933	establishment is handled in the background.
877		934
878	=item * Erlang suffers from silent message loss, AEMP does not.	935	=item * Erlang suffers from silent message loss, AEMP does not.
879		936
880	Erlang implements few guarantees on messages delivery - messages can get	937	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,	938	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).	939	b, and c, and the other side only receives messages a and c).
883		940
884	AEMP guarantees correct ordering, and the guarantee that after one message	941	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	942	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	943	same port are lost as well, until monitoring raises an error, so there are
887	sequence.	944	no silent "holes" in the message sequence.
		945
		946	If you want your software to be very reliable, you have to cope with
		947	corrupted and even out-of-order messages in both Erlang and AEMP. AEMP
		948	simply tries to work better in common error cases, such as when a network
		949	link goes down.
888		950
889	=item * Erlang can send messages to the wrong port, AEMP does not.	951	=item * Erlang can send messages to the wrong port, AEMP does not.
890		952
891	In Erlang it is quite likely that a node that restarts reuses a process ID	953	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	954	process ID known to other nodes for a completely different process,
893	destined for that process to end up in an unrelated process.	955	causing messages destined for that process to end up in an unrelated
		956	process.
894		957
895	AEMP never reuses port IDs, so old messages or old port IDs floating	958	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.	959	around in the network will not be sent to an unrelated port.
897		960
898	=item * Erlang uses unprotected connections, AEMP uses secure	961	=item * Erlang uses unprotected connections, AEMP uses secure
899	authentication and can use TLS.	962	authentication and can use TLS.
900		963
…		…
903		966
904	=item * The AEMP protocol is optimised for both text-based and binary	967	=item * The AEMP protocol is optimised for both text-based and binary
905	communications.	968	communications.
906		969
907	The AEMP protocol, unlike the Erlang protocol, supports both programming	970	The AEMP protocol, unlike the Erlang protocol, supports both programming
908	language independent text-only protocols (good for debugging) and binary,	971	language independent text-only protocols (good for debugging), and binary,
909	language-specific serialisers (e.g. Storable). By default, unless TLS is	972	language-specific serialisers (e.g. Storable). By default, unless TLS is
910	used, the protocol is actually completely text-based.	973	used, the protocol is actually completely text-based.
911		974
912	It has also been carefully designed to be implementable in other languages	975	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	976	with a minimum of work while gracefully degrading functionality to make the
914	protocol simple.	977	protocol simple.
915		978
916	=item * AEMP has more flexible monitoring options than Erlang.	979	=item * AEMP has more flexible monitoring options than Erlang.
917		980
918	In Erlang, you can chose to receive I<all> exit signals as messages	981	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	982	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	983	difficult to implement.
921	Erlang, as one can choose between automatic kill, exit message or callback	984
922	on a per-process basis.	985	Monitoring in AEMP is more flexible than in Erlang, as one can choose
		986	between automatic kill, exit message or callback on a per-port basis.
923		987
924	=item * Erlang tries to hide remote/local connections, AEMP does not.	988	=item * Erlang tries to hide remote/local connections, AEMP does not.
925		989
926	Monitoring in Erlang is not an indicator of process death/crashes, in the	990	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).	991	same way as linking is (except linking is unreliable in Erlang).
…		…
949	overhead, as well as having to keep a proxy object everywhere.	1013	overhead, as well as having to keep a proxy object everywhere.
950		1014
951	Strings can easily be printed, easily serialised etc. and need no special	1015	Strings can easily be printed, easily serialised etc. and need no special
952	procedures to be "valid".	1016	procedures to be "valid".
953		1017
954	And as a result, a miniport consists of a single closure stored in a	1018	And as a result, a port with just a default receiver consists of a single
955	global hash - it can't become much cheaper.	1019	code reference stored in a global hash - it can't become much cheaper.
956		1020
957	=item Why favour JSON, why not a real serialising format such as Storable?	1021	=item Why favour JSON, why not a real serialising format such as Storable?
958		1022
959	In fact, any AnyEvent::MP node will happily accept Storable as framing	1023	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	1024	format, but currently there is no way to make a node use Storable by
…		…
976		1040
977	L<AnyEvent::MP::Intro> - a gentle introduction.	1041	L<AnyEvent::MP::Intro> - a gentle introduction.
978		1042
979	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1043	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
980		1044
981	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	1045	L<AnyEvent::MP::Global> - network maintenance and port groups, to find
982	your applications.	1046	your applications.
		1047
		1048	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
983		1049
984	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from	1050	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
985	all nodes.	1051	all nodes.
986		1052
987	L<AnyEvent>.	1053	L<AnyEvent>.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.104 by root, Fri Nov 6 17:47:20 2009 UTC vs. Revision 1.121 by root, Tue Feb 28 18:37:24 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.104 by root, Fri Nov 6 17:47:20 2009 UTC vs.
Revision 1.121 by root, Tue Feb 28 18:37:24 2012 UTC