… | |
… | |
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 | |
… | |
… | |
155 | |
185 | |
156 | use AE (); |
186 | use AE (); |
157 | |
187 | |
158 | use base "Exporter"; |
188 | use base "Exporter"; |
159 | |
189 | |
160 | our $VERSION = 1.21; |
190 | our $VERSION = '1.30'; |
161 | |
191 | |
162 | our @EXPORT = qw( |
192 | our @EXPORT = qw( |
163 | NODE $NODE *SELF node_of after |
193 | NODE $NODE *SELF node_of after |
164 | configure |
194 | configure |
165 | snd rcv mon mon_guard kil psub peval spawn cal |
195 | snd rcv mon mon_guard kil psub peval spawn cal |
… | |
… | |
191 | Before a node can talk to other nodes on the network (i.e. enter |
221 | Before a node can talk to other nodes on the network (i.e. enter |
192 | "distributed mode") it has to configure itself - the minimum a node needs |
222 | "distributed mode") it has to configure itself - the minimum a node needs |
193 | to know is its own name, and optionally it should know the addresses of |
223 | 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. |
224 | some other nodes in the network to discover other nodes. |
195 | |
225 | |
|
|
226 | The key/value pairs are basically the same ones as documented for the |
|
|
227 | F<aemp> command line utility (sans the set/del prefix). |
|
|
228 | |
196 | This function configures a node - it must be called exactly once (or |
229 | This function configures a node - it must be called exactly once (or |
197 | never) before calling other AnyEvent::MP functions. |
230 | never) before calling other AnyEvent::MP functions. |
198 | |
231 | |
199 | =over 4 |
232 | =over 4 |
200 | |
233 | |
… | |
… | |
233 | used, meaning the node will bind on a dynamically-assigned port on every |
266 | used, meaning the node will bind on a dynamically-assigned port on every |
234 | local IP address it finds. |
267 | local IP address it finds. |
235 | |
268 | |
236 | =item step 3, connect to seed nodes |
269 | =item step 3, connect to seed nodes |
237 | |
270 | |
238 | As the last step, the seeds list from the profile is passed to the |
271 | 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 |
272 | L<AnyEvent::MP::Global> module, which will then use it to keep |
240 | connectivity with at least one node at any point in time. |
273 | connectivity with at least one node at any point in time. |
241 | |
274 | |
242 | =back |
275 | =back |
243 | |
276 | |
… | |
… | |
406 | if (ref $_[0]) { |
439 | if (ref $_[0]) { |
407 | if (my $self = $PORT_DATA{$portid}) { |
440 | if (my $self = $PORT_DATA{$portid}) { |
408 | "AnyEvent::MP::Port" eq ref $self |
441 | "AnyEvent::MP::Port" eq ref $self |
409 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
442 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
410 | |
443 | |
411 | $self->[2] = shift; |
444 | $self->[0] = shift; |
412 | } else { |
445 | } else { |
413 | my $cb = shift; |
446 | my $cb = shift; |
414 | $PORT{$portid} = sub { |
447 | $PORT{$portid} = sub { |
415 | local $SELF = $port; |
448 | local $SELF = $port; |
416 | eval { &$cb }; _self_die if $@; |
449 | eval { &$cb }; _self_die if $@; |
417 | }; |
450 | }; |
418 | } |
451 | } |
419 | } elsif (defined $_[0]) { |
452 | } elsif (defined $_[0]) { |
420 | my $self = $PORT_DATA{$portid} ||= do { |
453 | my $self = $PORT_DATA{$portid} ||= do { |
421 | my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
454 | my $self = bless [$PORT{$portid} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
422 | |
455 | |
423 | $PORT{$portid} = sub { |
456 | $PORT{$portid} = sub { |
424 | local $SELF = $port; |
457 | local $SELF = $port; |
425 | |
458 | |
426 | if (my $cb = $self->[1]{$_[0]}) { |
459 | if (my $cb = $self->[1]{$_[0]}) { |
… | |
… | |
492 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
525 | Remembers C<$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> |
526 | 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. |
527 | callbacks, i.e. runtime errors will cause the port to get C<kil>ed. |
495 | |
528 | |
496 | The effect is basically as if it returned C<< sub { peval $SELF, sub { |
529 | The effect is basically as if it returned C<< sub { peval $SELF, sub { |
497 | BLOCK } } >>. |
530 | BLOCK }, @_ } >>. |
498 | |
531 | |
499 | This is useful when you register callbacks from C<rcv> callbacks: |
532 | This is useful when you register callbacks from C<rcv> callbacks: |
500 | |
533 | |
501 | rcv delayed_reply => sub { |
534 | rcv delayed_reply => sub { |
502 | my ($delay, @reply) = @_; |
535 | my ($delay, @reply) = @_; |
… | |
… | |
650 | |
683 | |
651 | =item kil $port[, @reason] |
684 | =item kil $port[, @reason] |
652 | |
685 | |
653 | Kill the specified port with the given C<@reason>. |
686 | Kill the specified port with the given C<@reason>. |
654 | |
687 | |
655 | If no C<@reason> is specified, then the port is killed "normally" (ports |
688 | If no C<@reason> is specified, then the port is killed "normally" - |
656 | monitoring other ports will not necessarily die because a port dies |
689 | monitor callback will be invoked, but the kil will not cause linked ports |
657 | "normally"). |
690 | (C<mon $mport, $lport> form) to get killed. |
658 | |
691 | |
659 | Otherwise, linked ports get killed with the same reason (second form of |
692 | If a C<@reason> is specified, then linked ports (C<mon $mport, $lport> |
660 | C<mon>, see above). |
693 | form) get killed with the same reason. |
661 | |
694 | |
662 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
695 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
663 | will be reported as reason C<< die => $@ >>. |
696 | will be reported as reason C<< die => $@ >>. |
664 | |
697 | |
665 | Transport/communication errors are reported as C<< transport_error => |
698 | Transport/communication errors are reported as C<< transport_error => |
… | |
… | |
859 | ports being the special case/exception, where transport errors cannot |
892 | ports being the special case/exception, where transport errors cannot |
860 | occur. |
893 | occur. |
861 | |
894 | |
862 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
895 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
863 | |
896 | |
864 | Erlang uses processes that selectively receive messages, and therefore |
897 | Erlang uses processes that selectively receive messages out of order, and |
865 | needs a queue. AEMP is event based, queuing messages would serve no |
898 | therefore needs a queue. AEMP is event based, queuing messages would serve |
866 | useful purpose. For the same reason the pattern-matching abilities of |
899 | 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 |
900 | of AnyEvent::MP are more limited, as there is little need to be able to |
868 | filter messages without dequeuing them. |
901 | filter messages without dequeuing them. |
869 | |
902 | |
870 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
903 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
|
|
904 | being event-based, while Erlang is process-based. |
|
|
905 | |
|
|
906 | You cna have a look at L<Coro::MP> for a more Erlang-like process model on |
|
|
907 | top of AEMP and Coro threads. |
871 | |
908 | |
872 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
909 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
873 | |
910 | |
874 | Sending messages in Erlang is synchronous and blocks the process (and |
911 | Sending messages in Erlang is synchronous and blocks the process until |
|
|
912 | 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, |
913 | need a queue that can overflow). AEMP sends return immediately, connection |
876 | connection establishment is handled in the background. |
914 | establishment is handled in the background. |
877 | |
915 | |
878 | =item * Erlang suffers from silent message loss, AEMP does not. |
916 | =item * Erlang suffers from silent message loss, AEMP does not. |
879 | |
917 | |
880 | Erlang implements few guarantees on messages delivery - messages can get |
918 | 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, |
919 | 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). |
920 | b, and c, and the other side only receives messages a and c). |
883 | |
921 | |
884 | AEMP guarantees correct ordering, and the guarantee that after one message |
922 | 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 |
923 | 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 |
924 | same port are lost as well, until monitoring raises an error, so there are |
887 | sequence. |
925 | no silent "holes" in the message sequence. |
|
|
926 | |
|
|
927 | If you want your software to be very reliable, you have to cope with |
|
|
928 | corrupted and even out-of-order messages in both Erlang and AEMP. AEMP |
|
|
929 | simply tries to work better in common error cases, such as when a network |
|
|
930 | link goes down. |
888 | |
931 | |
889 | =item * Erlang can send messages to the wrong port, AEMP does not. |
932 | =item * Erlang can send messages to the wrong port, AEMP does not. |
890 | |
933 | |
891 | In Erlang it is quite likely that a node that restarts reuses a process ID |
934 | 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 |
935 | process ID known to other nodes for a completely different process, |
893 | destined for that process to end up in an unrelated process. |
936 | causing messages destined for that process to end up in an unrelated |
|
|
937 | process. |
894 | |
938 | |
895 | AEMP never reuses port IDs, so old messages or old port IDs floating |
939 | 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. |
940 | around in the network will not be sent to an unrelated port. |
897 | |
941 | |
898 | =item * Erlang uses unprotected connections, AEMP uses secure |
942 | =item * Erlang uses unprotected connections, AEMP uses secure |
899 | authentication and can use TLS. |
943 | authentication and can use TLS. |
900 | |
944 | |
… | |
… | |
903 | |
947 | |
904 | =item * The AEMP protocol is optimised for both text-based and binary |
948 | =item * The AEMP protocol is optimised for both text-based and binary |
905 | communications. |
949 | communications. |
906 | |
950 | |
907 | The AEMP protocol, unlike the Erlang protocol, supports both programming |
951 | The AEMP protocol, unlike the Erlang protocol, supports both programming |
908 | language independent text-only protocols (good for debugging) and binary, |
952 | language independent text-only protocols (good for debugging), and binary, |
909 | language-specific serialisers (e.g. Storable). By default, unless TLS is |
953 | language-specific serialisers (e.g. Storable). By default, unless TLS is |
910 | used, the protocol is actually completely text-based. |
954 | used, the protocol is actually completely text-based. |
911 | |
955 | |
912 | It has also been carefully designed to be implementable in other languages |
956 | 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 |
957 | with a minimum of work while gracefully degrading functionality to make the |
914 | protocol simple. |
958 | protocol simple. |
915 | |
959 | |
916 | =item * AEMP has more flexible monitoring options than Erlang. |
960 | =item * AEMP has more flexible monitoring options than Erlang. |
917 | |
961 | |
918 | In Erlang, you can chose to receive I<all> exit signals as messages |
962 | 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 |
963 | 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 |
964 | difficult to implement. |
921 | Erlang, as one can choose between automatic kill, exit message or callback |
965 | |
922 | on a per-process basis. |
966 | Monitoring in AEMP is more flexible than in Erlang, as one can choose |
|
|
967 | between automatic kill, exit message or callback on a per-port basis. |
923 | |
968 | |
924 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
969 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
925 | |
970 | |
926 | Monitoring in Erlang is not an indicator of process death/crashes, in the |
971 | 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). |
972 | same way as linking is (except linking is unreliable in Erlang). |
… | |
… | |
949 | overhead, as well as having to keep a proxy object everywhere. |
994 | overhead, as well as having to keep a proxy object everywhere. |
950 | |
995 | |
951 | Strings can easily be printed, easily serialised etc. and need no special |
996 | Strings can easily be printed, easily serialised etc. and need no special |
952 | procedures to be "valid". |
997 | procedures to be "valid". |
953 | |
998 | |
954 | And as a result, a miniport consists of a single closure stored in a |
999 | And as a result, a port with just a default receiver consists of a single |
955 | global hash - it can't become much cheaper. |
1000 | code reference stored in a global hash - it can't become much cheaper. |
956 | |
1001 | |
957 | =item Why favour JSON, why not a real serialising format such as Storable? |
1002 | =item Why favour JSON, why not a real serialising format such as Storable? |
958 | |
1003 | |
959 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
1004 | 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 |
1005 | format, but currently there is no way to make a node use Storable by |
… | |
… | |
976 | |
1021 | |
977 | L<AnyEvent::MP::Intro> - a gentle introduction. |
1022 | L<AnyEvent::MP::Intro> - a gentle introduction. |
978 | |
1023 | |
979 | L<AnyEvent::MP::Kernel> - more, lower-level, stuff. |
1024 | L<AnyEvent::MP::Kernel> - more, lower-level, stuff. |
980 | |
1025 | |
981 | L<AnyEvent::MP::Global> - network maintainance and port groups, to find |
1026 | L<AnyEvent::MP::Global> - network maintenance and port groups, to find |
982 | your applications. |
1027 | your applications. |
|
|
1028 | |
|
|
1029 | L<AnyEvent::MP::DataConn> - establish data connections between nodes. |
983 | |
1030 | |
984 | L<AnyEvent::MP::LogCatcher> - simple service to display log messages from |
1031 | L<AnyEvent::MP::LogCatcher> - simple service to display log messages from |
985 | all nodes. |
1032 | all nodes. |
986 | |
1033 | |
987 | L<AnyEvent>. |
1034 | L<AnyEvent>. |