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4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use AnyEvent::MP; |
7 | use AnyEvent::MP; |
8 | |
8 | |
9 | $NODE # contains this node's noderef |
9 | $NODE # contains this node's node ID |
10 | NODE # returns this node's noderef |
10 | NODE # returns this node's node ID |
11 | NODE $port # returns the noderef of the port |
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12 | |
11 | |
13 | $SELF # receiving/own port id in rcv callbacks |
12 | $SELF # receiving/own port id in rcv callbacks |
14 | |
13 | |
15 | # initialise the node so it can send/receive messages |
14 | # initialise the node so it can send/receive messages |
16 | initialise_node; |
15 | configure; |
17 | |
16 | |
18 | # ports are message endpoints |
17 | # ports are message destinations |
19 | |
18 | |
20 | # sending messages |
19 | # sending messages |
21 | snd $port, type => data...; |
20 | snd $port, type => data...; |
22 | snd $port, @msg; |
21 | snd $port, @msg; |
23 | snd @msg_with_first_element_being_a_port; |
22 | snd @msg_with_first_element_being_a_port; |
24 | |
23 | |
25 | # creating/using ports, the simple way |
24 | # creating/using ports, the simple way |
26 | my $simple_port = port { my @msg = @_; 0 }; |
25 | my $simple_port = port { my @msg = @_ }; |
27 | |
26 | |
28 | # creating/using ports, tagged message matching |
27 | # creating/using ports, tagged message matching |
29 | my $port = port; |
28 | my $port = port; |
30 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
29 | rcv $port, ping => sub { snd $_[0], "pong" }; |
31 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
30 | rcv $port, pong => sub { warn "pong received\n" }; |
32 | |
31 | |
33 | # create a port on another node |
32 | # create a port on another node |
34 | my $port = spawn $node, $initfunc, @initdata; |
33 | my $port = spawn $node, $initfunc, @initdata; |
35 | |
34 | |
36 | # monitoring |
35 | # monitoring |
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40 | |
39 | |
41 | =head1 CURRENT STATUS |
40 | =head1 CURRENT STATUS |
42 | |
41 | |
43 | bin/aemp - stable. |
42 | bin/aemp - stable. |
44 | AnyEvent::MP - stable API, should work. |
43 | AnyEvent::MP - stable API, should work. |
45 | AnyEvent::MP::Intro - uptodate, but incomplete. |
44 | AnyEvent::MP::Intro - explains most concepts. |
46 | AnyEvent::MP::Kernel - mostly stable. |
45 | AnyEvent::MP::Kernel - mostly stable. |
47 | AnyEvent::MP::Global - stable API, protocol not yet final. |
46 | AnyEvent::MP::Global - stable API, protocol not yet final. |
48 | |
47 | |
49 | stay tuned. |
48 | stay tuned. |
50 | |
49 | |
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55 | Despite its simplicity, you can securely message other processes running |
54 | Despite its simplicity, you can securely message other processes running |
56 | on the same or other hosts, and you can supervise entities remotely. |
55 | on the same or other hosts, and you can supervise entities remotely. |
57 | |
56 | |
58 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
57 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
59 | manual page and the examples under F<eg/>. |
58 | manual page and the examples under F<eg/>. |
60 | |
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61 | At the moment, this module family is a bit underdocumented. |
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62 | |
59 | |
63 | =head1 CONCEPTS |
60 | =head1 CONCEPTS |
64 | |
61 | |
65 | =over 4 |
62 | =over 4 |
66 | |
63 | |
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138 | |
135 | |
139 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
136 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
140 | |
137 | |
141 | our @EXPORT = qw( |
138 | our @EXPORT = qw( |
142 | NODE $NODE *SELF node_of after |
139 | NODE $NODE *SELF node_of after |
143 | initialise_node |
140 | configure |
144 | snd rcv mon mon_guard kil reg psub spawn |
141 | snd rcv mon mon_guard kil reg psub spawn |
145 | port |
142 | port |
146 | ); |
143 | ); |
147 | |
144 | |
148 | our $SELF; |
145 | our $SELF; |
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155 | |
152 | |
156 | =item $thisnode = NODE / $NODE |
153 | =item $thisnode = NODE / $NODE |
157 | |
154 | |
158 | The C<NODE> function returns, and the C<$NODE> variable contains, the node |
155 | The C<NODE> function returns, and the C<$NODE> variable contains, the node |
159 | ID of the node running in the current process. This value is initialised by |
156 | ID of the node running in the current process. This value is initialised by |
160 | a call to C<initialise_node>. |
157 | a call to C<configure>. |
161 | |
158 | |
162 | =item $nodeid = node_of $port |
159 | =item $nodeid = node_of $port |
163 | |
160 | |
164 | Extracts and returns the node ID from a port ID or a node ID. |
161 | Extracts and returns the node ID from a port ID or a node ID. |
165 | |
162 | |
166 | =item initialise_node $profile_name, key => value... |
163 | =item configure key => value... |
167 | |
164 | |
168 | Before a node can talk to other nodes on the network (i.e. enter |
165 | Before a node can talk to other nodes on the network (i.e. enter |
169 | "distributed mode") it has to initialise itself - the minimum a node needs |
166 | "distributed mode") it has to configure itself - the minimum a node needs |
170 | to know is its own name, and optionally it should know the addresses of |
167 | to know is its own name, and optionally it should know the addresses of |
171 | some other nodes in the network to discover other nodes. |
168 | some other nodes in the network to discover other nodes. |
172 | |
169 | |
173 | This function initialises a node - it must be called exactly once (or |
170 | This function configures a node - it must be called exactly once (or |
174 | never) before calling other AnyEvent::MP functions. |
171 | never) before calling other AnyEvent::MP functions. |
175 | |
172 | |
176 | The first argument is a profile name. If it is C<undef> or missing, then |
173 | =over 4 |
177 | the current nodename will be used instead (i.e. F<uname -n>). |
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178 | |
174 | |
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175 | =item step 1, gathering configuration from profiles |
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176 | |
179 | The function first looks up the profile in the aemp configuration (see the |
177 | The function first looks up a profile in the aemp configuration (see the |
180 | L<aemp> commandline utility). the profile is calculated as follows: |
178 | L<aemp> commandline utility). The profile name can be specified via the |
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179 | named C<profile> parameter. If it is missing, then the nodename (F<uname |
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180 | -n>) will be used as profile name. |
181 | |
181 | |
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182 | The profile data is then gathered as follows: |
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183 | |
182 | First, all remaining key => value pairs (all of which are conviniently |
184 | First, all remaining key => value pairs (all of which are conveniently |
183 | undocumented at the moment) will be used. Then they will be overwritten by |
185 | undocumented at the moment) will be interpreted as configuration |
184 | any values specified in the global default configuration (see the F<aemp> |
186 | data. Then they will be overwritten by any values specified in the global |
185 | utility), then the chain of profiles selected, if any. That means that |
187 | default configuration (see the F<aemp> utility), then the chain of |
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188 | profiles chosen by the profile name (and any C<parent> attributes). |
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189 | |
186 | the values specified in the profile have highest priority and the values |
190 | That means that the values specified in the profile have highest priority |
187 | specified via C<initialise_node> have lowest priority. |
191 | and the values specified directly via C<configure> have lowest priority, |
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192 | and can only be used to specify defaults. |
188 | |
193 | |
189 | If the profile specifies a node ID, then this will become the node ID of |
194 | If the profile specifies a node ID, then this will become the node ID of |
190 | this process. If not, then the profile name will be used as node ID. The |
195 | this process. If not, then the profile name will be used as node ID. The |
191 | special node ID of C<anon/> will be replaced by a random node ID. |
196 | special node ID of C<anon/> will be replaced by a random node ID. |
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197 | |
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198 | =item step 2, bind listener sockets |
192 | |
199 | |
193 | The next step is to look up the binds in the profile, followed by binding |
200 | The next step is to look up the binds in the profile, followed by binding |
194 | aemp protocol listeners on all binds specified (it is possible and valid |
201 | aemp protocol listeners on all binds specified (it is possible and valid |
195 | to have no binds, meaning that the node cannot be contacted form the |
202 | to have no binds, meaning that the node cannot be contacted form the |
196 | outside. This means the node cannot talk to other nodes that also have no |
203 | outside. This means the node cannot talk to other nodes that also have no |
197 | binds, but it can still talk to all "normal" nodes). |
204 | binds, but it can still talk to all "normal" nodes). |
198 | |
205 | |
199 | If the profile does not specify a binds list, then a default of C<*> is |
206 | If the profile does not specify a binds list, then a default of C<*> is |
200 | used. |
207 | used, meaning the node will bind on a dynamically-assigned port on every |
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208 | local IP address it finds. |
201 | |
209 | |
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210 | =item step 3, connect to seed nodes |
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211 | |
202 | Lastly, the seeds list from the profile is passed to the |
212 | As the last step, the seeds list from the profile is passed to the |
203 | L<AnyEvent::MP::Global> module, which will then use it to keep |
213 | L<AnyEvent::MP::Global> module, which will then use it to keep |
204 | connectivity with at least on of those seed nodes at any point in time. |
214 | connectivity with at least one node at any point in time. |
205 | |
215 | |
206 | Example: become a distributed node listening on the guessed noderef, or |
216 | =back |
207 | the one specified via C<aemp> for the current node. This should be the |
217 | |
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218 | Example: become a distributed node using the locla node name as profile. |
208 | most common form of invocation for "daemon"-type nodes. |
219 | This should be the most common form of invocation for "daemon"-type nodes. |
209 | |
220 | |
210 | initialise_node; |
221 | configure |
211 | |
222 | |
212 | Example: become an anonymous node. This form is often used for commandline |
223 | Example: become an anonymous node. This form is often used for commandline |
213 | clients. |
224 | clients. |
214 | |
225 | |
215 | initialise_node "anon/"; |
226 | configure nodeid => "anon/"; |
216 | |
227 | |
217 | Example: become a distributed node. If there is no profile of the given |
228 | Example: configure a node using a profile called seed, which si suitable |
218 | name, or no binds list was specified, resolve C<localhost:4044> and bind |
229 | for a seed node as it binds on all local addresses on a fixed port (4040, |
219 | on the resulting addresses. |
230 | customary for aemp). |
220 | |
231 | |
221 | initialise_node "localhost:4044"; |
232 | # use the aemp commandline utility |
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233 | # aemp profile seed nodeid anon/ binds '*:4040' |
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234 | |
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235 | # then use it |
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236 | configure profile => "seed"; |
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237 | |
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238 | # or simply use aemp from the shell again: |
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239 | # aemp run profile seed |
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240 | |
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241 | # or provide a nicer-to-remember nodeid |
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242 | # aemp run profile seed nodeid "$(hostname)" |
222 | |
243 | |
223 | =item $SELF |
244 | =item $SELF |
224 | |
245 | |
225 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
246 | Contains the current port id while executing C<rcv> callbacks or C<psub> |
226 | blocks. |
247 | blocks. |
… | |
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348 | |
369 | |
349 | =cut |
370 | =cut |
350 | |
371 | |
351 | sub rcv($@) { |
372 | sub rcv($@) { |
352 | my $port = shift; |
373 | my $port = shift; |
353 | my ($noderef, $portid) = split /#/, $port, 2; |
374 | my ($nodeid, $portid) = split /#/, $port, 2; |
354 | |
375 | |
355 | $NODE{$noderef} == $NODE{""} |
376 | $NODE{$nodeid} == $NODE{""} |
356 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
377 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
357 | |
378 | |
358 | while (@_) { |
379 | while (@_) { |
359 | if (ref $_[0]) { |
380 | if (ref $_[0]) { |
360 | if (my $self = $PORT_DATA{$portid}) { |
381 | if (my $self = $PORT_DATA{$portid}) { |
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468 | number of C<@reason> elements (no @reason means that the port was deleted |
489 | number of C<@reason> elements (no @reason means that the port was deleted |
469 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
490 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
470 | C<eval> if unsure. |
491 | C<eval> if unsure. |
471 | |
492 | |
472 | In the second form (another port given), the other port (C<$rcvport>) |
493 | In the second form (another port given), the other port (C<$rcvport>) |
473 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
494 | will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on |
474 | "normal" kils nothing happens, while under all other conditions, the other |
495 | "normal" kils nothing happens, while under all other conditions, the other |
475 | port is killed with the same reason. |
496 | port is killed with the same reason. |
476 | |
497 | |
477 | The third form (kill self) is the same as the second form, except that |
498 | The third form (kill self) is the same as the second form, except that |
478 | C<$rvport> defaults to C<$SELF>. |
499 | C<$rvport> defaults to C<$SELF>. |
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481 | C<snd>. |
502 | C<snd>. |
482 | |
503 | |
483 | As a rule of thumb, monitoring requests should always monitor a port from |
504 | As a rule of thumb, monitoring requests should always monitor a port from |
484 | a local port (or callback). The reason is that kill messages might get |
505 | a local port (or callback). The reason is that kill messages might get |
485 | lost, just like any other message. Another less obvious reason is that |
506 | lost, just like any other message. Another less obvious reason is that |
486 | even monitoring requests can get lost (for exmaple, when the connection |
507 | even monitoring requests can get lost (for example, when the connection |
487 | to the other node goes down permanently). When monitoring a port locally |
508 | to the other node goes down permanently). When monitoring a port locally |
488 | these problems do not exist. |
509 | these problems do not exist. |
489 | |
510 | |
490 | Example: call a given callback when C<$port> is killed. |
511 | Example: call a given callback when C<$port> is killed. |
491 | |
512 | |
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500 | mon $port, $self => "restart"; |
521 | mon $port, $self => "restart"; |
501 | |
522 | |
502 | =cut |
523 | =cut |
503 | |
524 | |
504 | sub mon { |
525 | sub mon { |
505 | my ($noderef, $port) = split /#/, shift, 2; |
526 | my ($nodeid, $port) = split /#/, shift, 2; |
506 | |
527 | |
507 | my $node = $NODE{$noderef} || add_node $noderef; |
528 | my $node = $NODE{$nodeid} || add_node $nodeid; |
508 | |
529 | |
509 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
530 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
510 | |
531 | |
511 | unless (ref $cb) { |
532 | unless (ref $cb) { |
512 | if (@_) { |
533 | if (@_) { |
… | |
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626 | }; |
647 | }; |
627 | _self_die if $@; |
648 | _self_die if $@; |
628 | } |
649 | } |
629 | |
650 | |
630 | sub spawn(@) { |
651 | sub spawn(@) { |
631 | my ($noderef, undef) = split /#/, shift, 2; |
652 | my ($nodeid, undef) = split /#/, shift, 2; |
632 | |
653 | |
633 | my $id = "$RUNIQ." . $ID++; |
654 | my $id = "$RUNIQ." . $ID++; |
634 | |
655 | |
635 | $_[0] =~ /::/ |
656 | $_[0] =~ /::/ |
636 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
657 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
637 | |
658 | |
638 | snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_; |
659 | snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_; |
639 | |
660 | |
640 | "$noderef#$id" |
661 | "$nodeid#$id" |
641 | } |
662 | } |
642 | |
663 | |
643 | =item after $timeout, @msg |
664 | =item after $timeout, @msg |
644 | |
665 | |
645 | =item after $timeout, $callback |
666 | =item after $timeout, $callback |
… | |
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684 | |
705 | |
685 | =item * Node IDs are arbitrary strings in AEMP. |
706 | =item * Node IDs are arbitrary strings in AEMP. |
686 | |
707 | |
687 | Erlang relies on special naming and DNS to work everywhere in the same |
708 | Erlang relies on special naming and DNS to work everywhere in the same |
688 | way. AEMP relies on each node somehow knowing its own address(es) (e.g. by |
709 | way. AEMP relies on each node somehow knowing its own address(es) (e.g. by |
689 | configuraiton or DNS), but will otherwise discover other odes itself. |
710 | configuration or DNS), but will otherwise discover other odes itself. |
690 | |
711 | |
691 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
712 | =item * Erlang has a "remote ports are like local ports" philosophy, AEMP |
692 | uses "local ports are like remote ports". |
713 | uses "local ports are like remote ports". |
693 | |
714 | |
694 | The failure modes for local ports are quite different (runtime errors |
715 | The failure modes for local ports are quite different (runtime errors |
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707 | |
728 | |
708 | Erlang uses processes that selectively receive messages, and therefore |
729 | Erlang uses processes that selectively receive messages, and therefore |
709 | needs a queue. AEMP is event based, queuing messages would serve no |
730 | needs a queue. AEMP is event based, queuing messages would serve no |
710 | useful purpose. For the same reason the pattern-matching abilities of |
731 | useful purpose. For the same reason the pattern-matching abilities of |
711 | AnyEvent::MP are more limited, as there is little need to be able to |
732 | AnyEvent::MP are more limited, as there is little need to be able to |
712 | filter messages without dequeing them. |
733 | filter messages without dequeuing them. |
713 | |
734 | |
714 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
735 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
715 | |
736 | |
716 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
737 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
717 | |
738 | |