1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent::MP - multi-processing/message-passing framework |
3 | AnyEvent::MP - erlang-style multi-processing/message-passing framework |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use AnyEvent::MP; |
7 | use AnyEvent::MP; |
8 | |
8 | |
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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 | # monitoring |
35 | # monitoring |
36 | mon $port, $cb->(@msg) # callback is invoked on death |
36 | mon $localport, $cb->(@msg) # callback is invoked on death |
37 | mon $port, $otherport # kill otherport on abnormal death |
37 | mon $localport, $otherport # kill otherport on abnormal death |
38 | mon $port, $otherport, @msg # send message on death |
38 | mon $localport, $otherport, @msg # send message on death |
39 | |
39 | |
40 | =head1 CURRENT STATUS |
40 | =head1 CURRENT STATUS |
41 | |
41 | |
42 | bin/aemp - stable. |
42 | bin/aemp - stable. |
43 | AnyEvent::MP - stable API, should work. |
43 | AnyEvent::MP - stable API, should work. |
44 | AnyEvent::MP::Intro - explains most concepts. |
44 | AnyEvent::MP::Intro - explains most concepts. |
45 | AnyEvent::MP::Kernel - mostly stable. |
45 | AnyEvent::MP::Kernel - mostly stable API. |
46 | AnyEvent::MP::Global - stable but incomplete, protocol not yet final. |
46 | AnyEvent::MP::Global - stable API. |
47 | |
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48 | stay tuned. |
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49 | |
47 | |
50 | =head1 DESCRIPTION |
48 | =head1 DESCRIPTION |
51 | |
49 | |
52 | This module (-family) implements a simple message passing framework. |
50 | This module (-family) implements a simple message passing framework. |
53 | |
51 | |
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109 | to have fixed listening addresses, seed nodes are perfectly normal nodes - |
107 | to have fixed listening addresses, seed nodes are perfectly normal nodes - |
110 | any node can function as a seed node for others. |
108 | any node can function as a seed node for others. |
111 | |
109 | |
112 | In addition to discovering the network, seed nodes are also used to |
110 | In addition to discovering the network, seed nodes are also used to |
113 | maintain the network and to connect nodes that otherwise would have |
111 | maintain the network and to connect nodes that otherwise would have |
114 | trouble connecting. They form the backbone of the AnyEvent::MP network. |
112 | trouble connecting. They form the backbone of an AnyEvent::MP network. |
115 | |
113 | |
116 | Seed nodes are expected to be long-running, and at least one seed node |
114 | Seed nodes are expected to be long-running, and at least one seed node |
117 | should always be available. They should also be relatively responsive - a |
115 | should always be available. They should also be relatively responsive - a |
118 | seed node that blocks for long periods will slow down everybody else. |
116 | seed node that blocks for long periods will slow down everybody else. |
119 | |
117 | |
120 | =item seeds - C<host:port> |
118 | =item seeds - C<host:port> |
121 | |
119 | |
122 | Seeds are transport endpoint(s) (usually a hostname/IP address and a |
120 | Seeds are transport endpoint(s) (usually a hostname/IP address and a |
123 | TCP port) of nodes thta should be used as seed nodes. |
121 | TCP port) of nodes that should be used as seed nodes. |
124 | |
122 | |
125 | The nodes listening on those endpoints are expected to be long-running, |
123 | The nodes listening on those endpoints are expected to be long-running, |
126 | and at least one of those should always be available. When nodes run out |
124 | and at least one of those should always be available. When nodes run out |
127 | of connections (e.g. due to a network error), they try to re-establish |
125 | of connections (e.g. due to a network error), they try to re-establish |
128 | connections to some seednodes again to join the network. |
126 | connections to some seednodes again to join the network. |
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145 | |
143 | |
146 | use AE (); |
144 | use AE (); |
147 | |
145 | |
148 | use base "Exporter"; |
146 | use base "Exporter"; |
149 | |
147 | |
150 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
148 | our $VERSION = 1.2; |
151 | |
149 | |
152 | our @EXPORT = qw( |
150 | our @EXPORT = qw( |
153 | NODE $NODE *SELF node_of after |
151 | NODE $NODE *SELF node_of after |
154 | configure |
152 | configure |
155 | snd rcv mon mon_guard kil reg psub spawn |
153 | snd rcv mon mon_guard kil psub spawn cal |
156 | port |
154 | port |
157 | ); |
155 | ); |
158 | |
156 | |
159 | our $SELF; |
157 | our $SELF; |
160 | |
158 | |
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229 | L<AnyEvent::MP::Global> module, which will then use it to keep |
227 | L<AnyEvent::MP::Global> module, which will then use it to keep |
230 | connectivity with at least one node at any point in time. |
228 | connectivity with at least one node at any point in time. |
231 | |
229 | |
232 | =back |
230 | =back |
233 | |
231 | |
234 | Example: become a distributed node using the locla node name as profile. |
232 | Example: become a distributed node using the local node name as profile. |
235 | This should be the most common form of invocation for "daemon"-type nodes. |
233 | This should be the most common form of invocation for "daemon"-type nodes. |
236 | |
234 | |
237 | configure |
235 | configure |
238 | |
236 | |
239 | Example: become an anonymous node. This form is often used for commandline |
237 | Example: become an anonymous node. This form is often used for commandline |
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525 | delivered again. |
523 | delivered again. |
526 | |
524 | |
527 | Inter-host-connection timeouts and monitoring depend on the transport |
525 | Inter-host-connection timeouts and monitoring depend on the transport |
528 | used. The only transport currently implemented is TCP, and AnyEvent::MP |
526 | used. The only transport currently implemented is TCP, and AnyEvent::MP |
529 | relies on TCP to detect node-downs (this can take 10-15 minutes on a |
527 | relies on TCP to detect node-downs (this can take 10-15 minutes on a |
530 | non-idle connection, and usually around two hours for idle conenctions). |
528 | non-idle connection, and usually around two hours for idle connections). |
531 | |
529 | |
532 | This means that monitoring is good for program errors and cleaning up |
530 | This means that monitoring is good for program errors and cleaning up |
533 | stuff eventually, but they are no replacement for a timeout when you need |
531 | stuff eventually, but they are no replacement for a timeout when you need |
534 | to ensure some maximum latency. |
532 | to ensure some maximum latency. |
535 | |
533 | |
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567 | } |
565 | } |
568 | |
566 | |
569 | $node->monitor ($port, $cb); |
567 | $node->monitor ($port, $cb); |
570 | |
568 | |
571 | defined wantarray |
569 | defined wantarray |
572 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
570 | and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }) |
573 | } |
571 | } |
574 | |
572 | |
575 | =item $guard = mon_guard $port, $ref, $ref... |
573 | =item $guard = mon_guard $port, $ref, $ref... |
576 | |
574 | |
577 | Monitors the given C<$port> and keeps the passed references. When the port |
575 | Monitors the given C<$port> and keeps the passed references. When the port |
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715 | ? $action[0]() |
713 | ? $action[0]() |
716 | : snd @action; |
714 | : snd @action; |
717 | }; |
715 | }; |
718 | } |
716 | } |
719 | |
717 | |
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718 | =item cal $port, @msg, $callback[, $timeout] |
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719 | |
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720 | A simple form of RPC - sends a message to the given C<$port> with the |
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721 | given contents (C<@msg>), but adds a reply port to the message. |
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722 | |
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723 | The reply port is created temporarily just for the purpose of receiving |
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724 | the reply, and will be C<kil>ed when no longer needed. |
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725 | |
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726 | A reply message sent to the port is passed to the C<$callback> as-is. |
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727 | |
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728 | If an optional time-out (in seconds) is given and it is not C<undef>, |
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729 | then the callback will be called without any arguments after the time-out |
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730 | elapsed and the port is C<kil>ed. |
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731 | |
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732 | If no time-out is given (or it is C<undef>), then the local port will |
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733 | monitor the remote port instead, so it eventually gets cleaned-up. |
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734 | |
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735 | Currently this function returns the temporary port, but this "feature" |
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736 | might go in future versions unless you can make a convincing case that |
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737 | this is indeed useful for something. |
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738 | |
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739 | =cut |
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740 | |
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741 | sub cal(@) { |
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742 | my $timeout = ref $_[-1] ? undef : pop; |
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743 | my $cb = pop; |
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744 | |
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745 | my $port = port { |
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746 | undef $timeout; |
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747 | kil $SELF; |
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748 | &$cb; |
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749 | }; |
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750 | |
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751 | if (defined $timeout) { |
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752 | $timeout = AE::timer $timeout, 0, sub { |
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753 | undef $timeout; |
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754 | kil $port; |
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755 | $cb->(); |
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756 | }; |
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757 | } else { |
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758 | mon $_[0], sub { |
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759 | kil $port; |
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760 | $cb->(); |
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761 | }; |
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762 | } |
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763 | |
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764 | push @_, $port; |
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765 | &snd; |
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766 | |
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767 | $port |
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768 | } |
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769 | |
720 | =back |
770 | =back |
721 | |
771 | |
722 | =head1 AnyEvent::MP vs. Distributed Erlang |
772 | =head1 AnyEvent::MP vs. Distributed Erlang |
723 | |
773 | |
724 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
774 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
725 | == aemp node, Erlang process == aemp port), so many of the documents and |
775 | == aemp node, Erlang process == aemp port), so many of the documents and |
726 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
776 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
727 | sample: |
777 | sample: |
728 | |
778 | |
729 | http://www.Erlang.se/doc/programming_rules.shtml |
779 | http://www.erlang.se/doc/programming_rules.shtml |
730 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
780 | http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
731 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
781 | http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6 |
732 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
782 | http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
733 | |
783 | |
734 | Despite the similarities, there are also some important differences: |
784 | Despite the similarities, there are also some important differences: |
735 | |
785 | |
736 | =over 4 |
786 | =over 4 |
737 | |
787 | |