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| 30 | This module (-family) implements a simple message passing framework. |
30 | This module (-family) implements a simple message passing framework. |
| 31 | |
31 | |
| 32 | Despite its simplicity, you can securely message other processes running |
32 | Despite its simplicity, you can securely message other processes running |
| 33 | on the same or other hosts. |
33 | on the same or other hosts. |
| 34 | |
34 | |
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35 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
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36 | manual page. |
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37 | |
| 35 | At the moment, this module family is severly brokena nd underdocumented, |
38 | At the moment, this module family is severly broken and underdocumented, |
| 36 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
39 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
| 37 | stay tuned! |
40 | stay tuned! The basic API should be finished, however. |
| 38 | |
41 | |
| 39 | =head1 CONCEPTS |
42 | =head1 CONCEPTS |
| 40 | |
43 | |
| 41 | =over 4 |
44 | =over 4 |
| 42 | |
45 | |
| … | |
… | |
| 85 | |
88 | |
| 86 | use AE (); |
89 | use AE (); |
| 87 | |
90 | |
| 88 | use base "Exporter"; |
91 | use base "Exporter"; |
| 89 | |
92 | |
| 90 | our $VERSION = '0.02'; |
93 | our $VERSION = '0.1'; |
| 91 | our @EXPORT = qw( |
94 | our @EXPORT = qw( |
| 92 | NODE $NODE *SELF node_of _any_ |
95 | NODE $NODE *SELF node_of _any_ |
| 93 | become_slave become_public |
96 | become_slave become_public |
| 94 | snd rcv mon kil reg psub |
97 | snd rcv mon kil reg psub |
| 95 | port |
98 | port |
| … | |
… | |
| 241 | sub mon_guard { |
244 | sub mon_guard { |
| 242 | my ($port, @refs) = @_; |
245 | my ($port, @refs) = @_; |
| 243 | |
246 | |
| 244 | mon $port, sub { 0 && @refs } |
247 | mon $port, sub { 0 && @refs } |
| 245 | } |
248 | } |
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249 | |
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250 | =item lnk $port1, $port2 |
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251 | |
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252 | Link two ports. This is simply a shorthand for: |
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253 | |
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254 | mon $port1, $port2; |
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255 | mon $port2, $port1; |
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256 | |
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257 | It means that if either one is killed abnormally, the other one gets |
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258 | killed as well. |
| 246 | |
259 | |
| 247 | =item $local_port = port |
260 | =item $local_port = port |
| 248 | |
261 | |
| 249 | Create a new local port object that supports message matching. |
262 | Create a new local port object that supports message matching. |
| 250 | |
263 | |
| … | |
… | |
| 495 | snd $NODE, time => $myport, timereply => 1, 2; |
508 | snd $NODE, time => $myport, timereply => 1, 2; |
| 496 | # => snd $myport, timereply => 1, 2, <time> |
509 | # => snd $myport, timereply => 1, 2, <time> |
| 497 | |
510 | |
| 498 | =back |
511 | =back |
| 499 | |
512 | |
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513 | =head1 AnyEvent::MP vs. Distributed Erlang |
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514 | |
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515 | AnyEvent::MP got lots of its ideas from distributed erlang. Despite the |
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516 | similarities (erlang node == aemp node, erlang process == aemp port and so |
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517 | on), there are also some important differences: |
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518 | |
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519 | =over 4 |
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520 | |
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521 | =item * Node references contain the recipe on how to contact them. |
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522 | |
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523 | Erlang relies on special naming and DNS to work everywhere in the |
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524 | same way. AEMP relies on each node knowing it's own address(es), with |
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525 | convenience functionality. |
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526 | |
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527 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
|
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528 | |
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529 | Erlang uses processes that selctively receive messages, and therefore |
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530 | needs a queue. AEMP is event based, queuing messages would serve no useful |
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531 | purpose. |
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532 | |
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533 | (But see L<Coro::MP> for a more erlang-like process model on top of AEMP). |
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534 | |
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535 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
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536 | |
|
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537 | Sending messages in erlang is synchronous and blocks the process. AEMP |
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538 | sends are immediate, connection establishment is handled in the |
|
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539 | background. |
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540 | |
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541 | =item * Erlang can silently lose messages, AEMP cannot. |
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542 | |
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543 | Erlang makes few guarantees on messages delivery - messages can get lost |
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544 | without any of the processes realising it (i.e. you send messages a, b, |
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545 | and c, and the other side only receives messages a and c). |
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546 | |
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547 | AEMP guarantees correct ordering, and the guarantee that there are no |
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548 | holes in the message sequence. |
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549 | |
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550 | =item * In erlang, processes can be declared dead and later be found to be |
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551 | alive. |
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552 | |
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553 | In erlang it can happen that a monitored process is declared dead and |
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554 | linked processes get killed, but later it turns out that the process is |
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555 | still alive - and can receive messages. |
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556 | |
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557 | In AEMP, when port monitoring detects a port as dead, then that port will |
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558 | eventually be killed - it cannot happen that a node detects a port as dead |
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559 | and then later sends messages to it, finding it is still alive. |
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560 | |
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561 | =item * Erlang can send messages to the wrong port, AEMP does not. |
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562 | |
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563 | In erlang it is quite possible that a node that restarts reuses a process |
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564 | ID known to other nodes for a completely different process, causing |
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565 | messages destined for that process to end up in an unrelated process. |
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566 | |
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567 | AEMP never reuses port IDs, so old messages or old port IDs floating |
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568 | around in the network will not be sent to an unrelated port. |
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569 | |
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570 | =item * Erlang uses unprotected connections, AEMP uses secure |
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571 | authentication and can use TLS. |
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572 | |
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573 | AEMP can use a proven protocol - SSL/TLS - to protect connections and |
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574 | securely authenticate nodes. |
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575 | |
|
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576 | =back |
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577 | |
| 500 | =head1 SEE ALSO |
578 | =head1 SEE ALSO |
| 501 | |
579 | |
| 502 | L<AnyEvent>. |
580 | L<AnyEvent>. |
| 503 | |
581 | |
| 504 | =head1 AUTHOR |
582 | =head1 AUTHOR |
