… | |
… | |
47 | # execute callbacks in $SELF port context |
47 | # execute callbacks in $SELF port context |
48 | my $timer = AE::timer 1, 0, psub { |
48 | my $timer = AE::timer 1, 0, psub { |
49 | die "kill the port, delayed"; |
49 | die "kill the port, delayed"; |
50 | }; |
50 | }; |
51 | |
51 | |
52 | =head1 CURRENT STATUS |
52 | # distributed database - modification |
|
|
53 | db_set $family => $subkey [=> $value] # add a subkey |
|
|
54 | db_del $family => $subkey... # delete one or more subkeys |
|
|
55 | db_reg $family => $port [=> $value] # register a port |
53 | |
56 | |
54 | bin/aemp - stable. |
57 | # distributed database - queries |
55 | AnyEvent::MP - stable API, should work. |
58 | db_family $family => $cb->(\%familyhash) |
56 | AnyEvent::MP::Intro - explains most concepts. |
59 | db_keys $family => $cb->(\@keys) |
57 | AnyEvent::MP::Kernel - mostly stable API. |
60 | db_values $family => $cb->(\@values) |
58 | AnyEvent::MP::Global - stable API. |
61 | |
|
|
62 | # distributed database - monitoring a family |
|
|
63 | db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted) |
59 | |
64 | |
60 | =head1 DESCRIPTION |
65 | =head1 DESCRIPTION |
61 | |
66 | |
62 | This module (-family) implements a simple message passing framework. |
67 | This module (-family) implements a simple message passing framework. |
63 | |
68 | |
… | |
… | |
113 | each other. To do this, nodes should listen on one or more local transport |
118 | each other. To do this, nodes should listen on one or more local transport |
114 | endpoints - binds. |
119 | endpoints - binds. |
115 | |
120 | |
116 | Currently, only standard C<ip:port> specifications can be used, which |
121 | Currently, only standard C<ip:port> specifications can be used, which |
117 | specify TCP ports to listen on. So a bind is basically just a tcp socket |
122 | specify TCP ports to listen on. So a bind is basically just a tcp socket |
118 | in listening mode thta accepts conenctions form other nodes. |
123 | in listening mode that accepts connections from other nodes. |
119 | |
124 | |
120 | =item seed nodes |
125 | =item seed nodes |
121 | |
126 | |
122 | When a node starts, it knows nothing about the network it is in - it |
127 | When a node starts, it knows nothing about the network it is in - it |
123 | needs to connect to at least one other node that is already in the |
128 | needs to connect to at least one other node that is already in the |
124 | network. These other nodes are called "seed nodes". |
129 | network. These other nodes are called "seed nodes". |
125 | |
130 | |
126 | Seed nodes themselves are not special - they are seed nodes only because |
131 | Seed nodes themselves are not special - they are seed nodes only because |
127 | some other node I<uses> them as such, but any node can be used as seed |
132 | some other node I<uses> them as such, but any node can be used as seed |
128 | node for other nodes, and eahc node cna use a different set of seed nodes. |
133 | node for other nodes, and eahc node can use a different set of seed nodes. |
129 | |
134 | |
130 | In addition to discovering the network, seed nodes are also used to |
135 | In addition to discovering the network, seed nodes are also used to |
131 | maintain the network - all nodes using the same seed node form are part of |
136 | maintain the network - all nodes using the same seed node are part of the |
132 | the same network. If a network is split into multiple subnets because e.g. |
137 | same network. If a network is split into multiple subnets because e.g. the |
133 | the network link between the parts goes down, then using the same seed |
138 | network link between the parts goes down, then using the same seed nodes |
134 | nodes for all nodes ensures that eventually the subnets get merged again. |
139 | for all nodes ensures that eventually the subnets get merged again. |
135 | |
140 | |
136 | Seed nodes are expected to be long-running, and at least one seed node |
141 | Seed nodes are expected to be long-running, and at least one seed node |
137 | should always be available. They should also be relatively responsive - a |
142 | should always be available. They should also be relatively responsive - a |
138 | seed node that blocks for long periods will slow down everybody else. |
143 | seed node that blocks for long periods will slow down everybody else. |
139 | |
144 | |
… | |
… | |
163 | |
168 | |
164 | Any node that loads the L<AnyEvent::MP::Global> module becomes a global |
169 | Any node that loads the L<AnyEvent::MP::Global> module becomes a global |
165 | node and tries to keep connections to all other nodes. So while it can |
170 | node and tries to keep connections to all other nodes. So while it can |
166 | make sense to make every node "global" in small networks, it usually makes |
171 | make sense to make every node "global" in small networks, it usually makes |
167 | sense to only make seed nodes into global nodes in large networks (nodes |
172 | sense to only make seed nodes into global nodes in large networks (nodes |
168 | keep connections to seed nodes and global nodes, so makign them the same |
173 | keep connections to seed nodes and global nodes, so making them the same |
169 | reduces overhead). |
174 | reduces overhead). |
170 | |
175 | |
171 | =back |
176 | =back |
172 | |
177 | |
173 | =head1 VARIABLES/FUNCTIONS |
178 | =head1 VARIABLES/FUNCTIONS |
… | |
… | |
178 | |
183 | |
179 | package AnyEvent::MP; |
184 | package AnyEvent::MP; |
180 | |
185 | |
181 | use AnyEvent::MP::Config (); |
186 | use AnyEvent::MP::Config (); |
182 | use AnyEvent::MP::Kernel; |
187 | use AnyEvent::MP::Kernel; |
183 | use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); |
188 | use AnyEvent::MP::Kernel qw( |
|
|
189 | %NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID |
|
|
190 | add_node load_func |
|
|
191 | |
|
|
192 | NODE $NODE |
|
|
193 | configure |
|
|
194 | node_of port_is_local |
|
|
195 | snd kil |
|
|
196 | db_set db_del |
|
|
197 | db_mon db_family db_keys db_values |
|
|
198 | ); |
184 | |
199 | |
185 | use common::sense; |
200 | use common::sense; |
186 | |
201 | |
187 | use Carp (); |
202 | use Carp (); |
188 | |
203 | |
189 | use AE (); |
204 | use AnyEvent (); |
190 | use Guard (); |
205 | use Guard (); |
191 | |
206 | |
192 | use base "Exporter"; |
207 | use base "Exporter"; |
193 | |
208 | |
194 | our $VERSION = $AnyEvent::MP::Config::VERSION; |
209 | our $VERSION = '2.02'; # also in MP/Config.pm |
195 | |
210 | |
196 | our @EXPORT = qw( |
211 | our @EXPORT = qw( |
197 | NODE $NODE *SELF node_of after |
|
|
198 | configure |
212 | configure |
|
|
213 | |
|
|
214 | NODE $NODE |
|
|
215 | *SELF |
|
|
216 | |
|
|
217 | node_of port_is_local |
|
|
218 | |
|
|
219 | snd kil |
199 | snd rcv mon mon_guard kil psub peval spawn cal |
220 | port rcv mon mon_guard psub peval spawn cal |
200 | port |
|
|
201 | db_set db_del db_reg |
221 | db_set db_del db_reg |
202 | db_mon db_family db_keys db_values |
222 | db_mon db_family db_keys db_values |
|
|
223 | |
|
|
224 | after |
203 | ); |
225 | ); |
204 | |
226 | |
205 | our $SELF; |
227 | our $SELF; |
206 | |
228 | |
207 | sub _self_die() { |
229 | sub _self_die() { |
… | |
… | |
218 | |
240 | |
219 | =item $nodeid = node_of $port |
241 | =item $nodeid = node_of $port |
220 | |
242 | |
221 | Extracts and returns the node ID from a port ID or a node ID. |
243 | Extracts and returns the node ID from a port ID or a node ID. |
222 | |
244 | |
|
|
245 | =item $is_local = port_is_local $port |
|
|
246 | |
|
|
247 | Returns true iff the port is a local port. |
|
|
248 | |
223 | =item configure $profile, key => value... |
249 | =item configure $profile, key => value... |
224 | |
250 | |
225 | =item configure key => value... |
251 | =item configure key => value... |
226 | |
252 | |
227 | Before a node can talk to other nodes on the network (i.e. enter |
253 | Before a node can talk to other nodes on the network (i.e. enter |
… | |
… | |
238 | =over 4 |
264 | =over 4 |
239 | |
265 | |
240 | =item norc => $boolean (default false) |
266 | =item norc => $boolean (default false) |
241 | |
267 | |
242 | If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> |
268 | If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> |
243 | be consulted - all configuraiton options must be specified in the |
269 | be consulted - all configuration options must be specified in the |
244 | C<configure> call. |
270 | C<configure> call. |
245 | |
271 | |
246 | =item force => $boolean (default false) |
272 | =item force => $boolean (default false) |
247 | |
273 | |
248 | IF true, then the values specified in the C<configure> will take |
274 | IF true, then the values specified in the C<configure> will take |
249 | precedence over any values configured via the rc file. The default is for |
275 | precedence over any values configured via the rc file. The default is for |
250 | the rc file to override any options specified in the program. |
276 | the rc file to override any options specified in the program. |
251 | |
|
|
252 | =item secure => $pass->(@msg) |
|
|
253 | |
|
|
254 | In addition to specifying a boolean, you can specify a code reference that |
|
|
255 | is called for every code execution attempt - the execution request is |
|
|
256 | granted iff the callback returns a true value. |
|
|
257 | |
|
|
258 | Most of the time the callback should look only at |
|
|
259 | C<$AnyEvent::MP::Kernel::SRCNODE> to make a decision, and not at the |
|
|
260 | actual message (which can be about anything, and is mostly provided for |
|
|
261 | diagnostic purposes). |
|
|
262 | |
|
|
263 | See F<semp setsecure> for more info. |
|
|
264 | |
277 | |
265 | =back |
278 | =back |
266 | |
279 | |
267 | =over 4 |
280 | =over 4 |
268 | |
281 | |
… | |
… | |
289 | this process. If not, then the profile name will be used as node ID, with |
302 | this process. If not, then the profile name will be used as node ID, with |
290 | a unique randoms tring (C</%u>) appended. |
303 | a unique randoms tring (C</%u>) appended. |
291 | |
304 | |
292 | The node ID can contain some C<%> sequences that are expanded: C<%n> |
305 | The node ID can contain some C<%> sequences that are expanded: C<%n> |
293 | is expanded to the local nodename, C<%u> is replaced by a random |
306 | is expanded to the local nodename, C<%u> is replaced by a random |
294 | strign to make the node unique. For example, the F<aemp> commandline |
307 | string to make the node unique. For example, the F<aemp> commandline |
295 | utility uses C<aemp/%n/%u> as nodename, which might expand to |
308 | utility uses C<aemp/%n/%u> as nodename, which might expand to |
296 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
309 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
297 | |
310 | |
298 | =item step 2, bind listener sockets |
311 | =item step 2, bind listener sockets |
299 | |
312 | |
300 | The next step is to look up the binds in the profile, followed by binding |
313 | The next step is to look up the binds in the profile, followed by binding |
301 | aemp protocol listeners on all binds specified (it is possible and valid |
314 | aemp protocol listeners on all binds specified (it is possible and valid |
302 | to have no binds, meaning that the node cannot be contacted form the |
315 | to have no binds, meaning that the node cannot be contacted from the |
303 | outside. This means the node cannot talk to other nodes that also have no |
316 | outside. This means the node cannot talk to other nodes that also have no |
304 | binds, but it can still talk to all "normal" nodes). |
317 | binds, but it can still talk to all "normal" nodes). |
305 | |
318 | |
306 | If the profile does not specify a binds list, then a default of C<*> is |
319 | If the profile does not specify a binds list, then a default of C<*> is |
307 | used, meaning the node will bind on a dynamically-assigned port on every |
320 | used, meaning the node will bind on a dynamically-assigned port on every |
… | |
… | |
404 | =cut |
417 | =cut |
405 | |
418 | |
406 | sub rcv($@); |
419 | sub rcv($@); |
407 | |
420 | |
408 | my $KILME = sub { |
421 | my $KILME = sub { |
409 | (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; |
422 | (my $tag = substr $_[0], 0, 30) =~ s/([^\x20-\x7e])/./g; |
410 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
423 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
411 | }; |
424 | }; |
412 | |
425 | |
413 | sub port(;&) { |
426 | sub port(;&) { |
414 | my $id = $UNIQ . ++$ID; |
427 | my $id = $UNIQ . ++$ID; |
… | |
… | |
472 | |
485 | |
473 | sub rcv($@) { |
486 | sub rcv($@) { |
474 | my $port = shift; |
487 | my $port = shift; |
475 | my ($nodeid, $portid) = split /#/, $port, 2; |
488 | my ($nodeid, $portid) = split /#/, $port, 2; |
476 | |
489 | |
477 | $NODE{$nodeid} == $NODE{""} |
490 | $nodeid eq $NODE |
478 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
491 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
479 | |
492 | |
480 | while (@_) { |
493 | while (@_) { |
481 | if (ref $_[0]) { |
494 | if (ref $_[0]) { |
482 | if (my $self = $PORT_DATA{$portid}) { |
495 | if (my $self = $PORT_DATA{$portid}) { |
… | |
… | |
525 | $port |
538 | $port |
526 | } |
539 | } |
527 | |
540 | |
528 | =item peval $port, $coderef[, @args] |
541 | =item peval $port, $coderef[, @args] |
529 | |
542 | |
530 | Evaluates the given C<$codref> within the contetx of C<$port>, that is, |
543 | Evaluates the given C<$codref> within the context of C<$port>, that is, |
531 | when the code throews an exception the C<$port> will be killed. |
544 | when the code throws an exception the C<$port> will be killed. |
532 | |
545 | |
533 | Any remaining args will be passed to the callback. Any return values will |
546 | Any remaining args will be passed to the callback. Any return values will |
534 | be returned to the caller. |
547 | be returned to the caller. |
535 | |
548 | |
536 | This is useful when you temporarily want to execute code in the context of |
549 | This is useful when you temporarily want to execute code in the context of |
… | |
… | |
601 | $res |
614 | $res |
602 | } |
615 | } |
603 | } |
616 | } |
604 | } |
617 | } |
605 | |
618 | |
|
|
619 | =item $guard = mon $port, $rcvport # kill $rcvport when $port dies |
|
|
620 | |
|
|
621 | =item $guard = mon $port # kill $SELF when $port dies |
|
|
622 | |
606 | =item $guard = mon $port, $cb->(@reason) # call $cb when $port dies |
623 | =item $guard = mon $port, $cb->(@reason) # call $cb when $port dies |
607 | |
|
|
608 | =item $guard = mon $port, $rcvport # kill $rcvport when $port dies |
|
|
609 | |
|
|
610 | =item $guard = mon $port # kill $SELF when $port dies |
|
|
611 | |
624 | |
612 | =item $guard = mon $port, $rcvport, @msg # send a message when $port dies |
625 | =item $guard = mon $port, $rcvport, @msg # send a message when $port dies |
613 | |
626 | |
614 | Monitor the given port and do something when the port is killed or |
627 | Monitor the given port and do something when the port is killed or |
615 | messages to it were lost, and optionally return a guard that can be used |
628 | messages to it were lost, and optionally return a guard that can be used |
616 | to stop monitoring again. |
629 | to stop monitoring again. |
617 | |
630 | |
|
|
631 | The first two forms distinguish between "normal" and "abnormal" kil's: |
|
|
632 | |
|
|
633 | In the first form (another port given), if the C<$port> is C<kil>'ed with |
|
|
634 | a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the |
|
|
635 | same reason. That is, on "normal" kil's nothing happens, while under all |
|
|
636 | other conditions, the other port is killed with the same reason. |
|
|
637 | |
|
|
638 | The second form (kill self) is the same as the first form, except that |
|
|
639 | C<$rvport> defaults to C<$SELF>. |
|
|
640 | |
|
|
641 | The remaining forms don't distinguish between "normal" and "abnormal" kil's |
|
|
642 | - it's up to the callback or receiver to check whether the C<@reason> is |
|
|
643 | empty and act accordingly. |
|
|
644 | |
618 | In the first form (callback), the callback is simply called with any |
645 | In the third form (callback), the callback is simply called with any |
619 | number of C<@reason> elements (no @reason means that the port was deleted |
646 | number of C<@reason> elements (empty @reason means that the port was deleted |
620 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
647 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
621 | C<eval> if unsure. |
648 | C<eval> if unsure. |
622 | |
649 | |
623 | In the second form (another port given), the other port (C<$rcvport>) |
|
|
624 | will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on |
|
|
625 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
626 | port is killed with the same reason. |
|
|
627 | |
|
|
628 | The third form (kill self) is the same as the second form, except that |
|
|
629 | C<$rvport> defaults to C<$SELF>. |
|
|
630 | |
|
|
631 | In the last form (message), a message of the form C<@msg, @reason> will be |
650 | In the last form (message), a message of the form C<$rcvport, @msg, |
632 | C<snd>. |
651 | @reason> will be C<snd>. |
633 | |
652 | |
634 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
653 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
635 | alert was raised), they are removed and will not trigger again. |
654 | alert was raised), they are removed and will not trigger again, even if it |
|
|
655 | turns out that the port is still alive (but monitoring actions added after |
|
|
656 | that will again trigger). |
636 | |
657 | |
637 | As a rule of thumb, monitoring requests should always monitor a port from |
658 | As a rule of thumb, monitoring requests should always monitor a remote |
638 | a local port (or callback). The reason is that kill messages might get |
659 | port locally (using a local C<$rcvport> or a callback). The reason is that |
639 | lost, just like any other message. Another less obvious reason is that |
660 | kill messages might get lost, just like any other message. Another less |
640 | even monitoring requests can get lost (for example, when the connection |
661 | obvious reason is that even monitoring requests can get lost (for example, |
641 | to the other node goes down permanently). When monitoring a port locally |
662 | when the connection to the other node goes down permanently). When |
642 | these problems do not exist. |
663 | monitoring a port locally these problems do not exist. |
643 | |
664 | |
644 | C<mon> effectively guarantees that, in the absence of hardware failures, |
665 | C<mon> effectively guarantees that, in the absence of hardware failures, |
645 | after starting the monitor, either all messages sent to the port will |
666 | after starting the monitor, either all messages sent to the port will |
646 | arrive, or the monitoring action will be invoked after possible message |
667 | arrive, or the monitoring action will be invoked after possible message |
647 | loss has been detected. No messages will be lost "in between" (after |
668 | loss has been detected. No messages will be lost "in between" (after |
… | |
… | |
856 | #=item $cb2 = timeout $seconds, $cb[, @args] |
877 | #=item $cb2 = timeout $seconds, $cb[, @args] |
857 | |
878 | |
858 | =item cal $port, @msg, $callback[, $timeout] |
879 | =item cal $port, @msg, $callback[, $timeout] |
859 | |
880 | |
860 | A simple form of RPC - sends a message to the given C<$port> with the |
881 | A simple form of RPC - sends a message to the given C<$port> with the |
861 | given contents (C<@msg>), but adds a reply port to the message. |
882 | given contents (C<@msg>), but appends a reply port to the message. |
862 | |
883 | |
863 | The reply port is created temporarily just for the purpose of receiving |
884 | The reply port is created temporarily just for the purpose of receiving |
864 | the reply, and will be C<kil>ed when no longer needed. |
885 | the reply, and will be C<kil>ed when no longer needed. |
865 | |
886 | |
866 | A reply message sent to the port is passed to the C<$callback> as-is. |
887 | A reply message sent to the port is passed to the C<$callback> as-is. |
… | |
… | |
1034 | =item db_values $family => $cb->(\@values) |
1055 | =item db_values $family => $cb->(\@values) |
1035 | |
1056 | |
1036 | Same as C<db_family>, except it only queries the family I<values> and passes them |
1057 | Same as C<db_family>, except it only queries the family I<values> and passes them |
1037 | as array reference to the callback. |
1058 | as array reference to the callback. |
1038 | |
1059 | |
1039 | =item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted) |
1060 | =item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted) |
1040 | |
1061 | |
1041 | Creates a monitor on the given database family. Each time a key is set |
1062 | Creates a monitor on the given database family. Each time a key is |
1042 | or or is deleted the callback is called with a hash containing the |
1063 | set or is deleted the callback is called with a hash containing the |
1043 | database family and three lists of added, changed and deleted subkeys, |
1064 | database family and three lists of added, changed and deleted subkeys, |
1044 | respectively. If no keys have changed then the array reference might be |
1065 | respectively. If no keys have changed then the array reference might be |
1045 | C<undef> or even missing. |
1066 | C<undef> or even missing. |
1046 | |
1067 | |
1047 | If not called in void context, a guard object is returned that, when |
1068 | If not called in void context, a guard object is returned that, when |
… | |
… | |
1075 | return unless %$family; |
1096 | return unless %$family; |
1076 | undef $guard; |
1097 | undef $guard; |
1077 | print "My::Module::workers now nonempty\n"; |
1098 | print "My::Module::workers now nonempty\n"; |
1078 | }; |
1099 | }; |
1079 | |
1100 | |
1080 | Example: print all changes to the family "AnyRvent::Fantasy::Module". |
1101 | Example: print all changes to the family "AnyEvent::Fantasy::Module". |
1081 | |
1102 | |
1082 | my $guard = db_mon AnyRvent::Fantasy::Module => sub { |
1103 | my $guard = db_mon AnyEvent::Fantasy::Module => sub { |
1083 | my ($family, $a, $c, $d) = @_; |
1104 | my ($family, $a, $c, $d) = @_; |
1084 | |
1105 | |
1085 | print "+$_=$family->{$_}\n" for @$a; |
1106 | print "+$_=$family->{$_}\n" for @$a; |
1086 | print "*$_=$family->{$_}\n" for @$c; |
1107 | print "*$_=$family->{$_}\n" for @$c; |
1087 | print "-$_=$family->{$_}\n" for @$d; |
1108 | print "-$_=$family->{$_}\n" for @$d; |
… | |
… | |
1138 | filter messages without dequeuing them. |
1159 | filter messages without dequeuing them. |
1139 | |
1160 | |
1140 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
1161 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
1141 | being event-based, while Erlang is process-based. |
1162 | being event-based, while Erlang is process-based. |
1142 | |
1163 | |
1143 | You cna have a look at L<Coro::MP> for a more Erlang-like process model on |
1164 | You can have a look at L<Coro::MP> for a more Erlang-like process model on |
1144 | top of AEMP and Coro threads. |
1165 | top of AEMP and Coro threads. |
1145 | |
1166 | |
1146 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
1167 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
1147 | |
1168 | |
1148 | Sending messages in Erlang is synchronous and blocks the process until |
1169 | Sending messages in Erlang is synchronous and blocks the process until |
1149 | a conenction has been established and the message sent (and so does not |
1170 | a connection has been established and the message sent (and so does not |
1150 | need a queue that can overflow). AEMP sends return immediately, connection |
1171 | need a queue that can overflow). AEMP sends return immediately, connection |
1151 | establishment is handled in the background. |
1172 | establishment is handled in the background. |
1152 | |
1173 | |
1153 | =item * Erlang suffers from silent message loss, AEMP does not. |
1174 | =item * Erlang suffers from silent message loss, AEMP does not. |
1154 | |
1175 | |
… | |
… | |
1254 | |
1275 | |
1255 | =back |
1276 | =back |
1256 | |
1277 | |
1257 | =head1 PORTING FROM AnyEvent::MP VERSION 1.X |
1278 | =head1 PORTING FROM AnyEvent::MP VERSION 1.X |
1258 | |
1279 | |
1259 | AEMP version 2 has three major incompatible changes compared to version 1: |
1280 | AEMP version 2 has a few major incompatible changes compared to version 1: |
1260 | |
1281 | |
1261 | =over 4 |
1282 | =over 4 |
1262 | |
1283 | |
1263 | =item AnyEvent::MP::Global no longer has group management functions. |
1284 | =item AnyEvent::MP::Global no longer has group management functions. |
1264 | |
1285 | |
|
|
1286 | At least not officially - the grp_* functions are still exported and might |
|
|
1287 | work, but they will be removed in some later release. |
|
|
1288 | |
1265 | AnyEvent::MP now comes with a distributed database that is more |
1289 | AnyEvent::MP now comes with a distributed database that is more |
1266 | powerful. It's database families map closely to ports, but the API has |
1290 | powerful. Its database families map closely to port groups, but the API |
1267 | minor differences: |
1291 | has changed (the functions are also now exported by AnyEvent::MP). Here is |
|
|
1292 | a rough porting guide: |
1268 | |
1293 | |
1269 | grp_reg $group, $port # old |
1294 | grp_reg $group, $port # old |
1270 | db_reg $group, $port # new |
1295 | db_reg $group, $port # new |
1271 | |
1296 | |
1272 | $list = grp_get $group # old |
1297 | $list = grp_get $group # old |
1273 | db_keys $group, sub { my $list = shift } # new |
1298 | db_keys $group, sub { my $list = shift } # new |
1274 | |
1299 | |
1275 | grp_mon $group, $cb->(\@ports, $add, $del) # old |
1300 | grp_mon $group, $cb->(\@ports, $add, $del) # old |
1276 | db_mon $group, $cb->(\%ports, $add, $change, $del) # new |
1301 | db_mon $group, $cb->(\%ports, $add, $change, $del) # new |
1277 | |
1302 | |
1278 | C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> |
1303 | C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is |
1279 | is no longer instant, because the local node might not have a copy of |
1304 | no longer instant, because the local node might not have a copy of the |
1280 | the group. This can be partially remedied by using C<db_mon> to keep an |
1305 | group. You can either modify your code to allow for a callback, or use |
1281 | updated copy of the group: |
1306 | C<db_mon> to keep an updated copy of the group: |
1282 | |
1307 | |
1283 | my $local_group_copy; |
1308 | my $local_group_copy; |
1284 | db_mon $group => sub { $local_group_copy = shift }; |
1309 | db_mon $group => sub { $local_group_copy = $_[0] }; |
1285 | |
1310 | |
1286 | # no keys %$local_group_copy always returns the most up-to-date |
1311 | # now "keys %$local_group_copy" always returns the most up-to-date |
1287 | # list of ports in the group. |
1312 | # list of ports in the group. |
1288 | |
1313 | |
1289 | C<grp_mon> can almost be replaced by C<db_mon>: |
1314 | C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon> |
|
|
1315 | passes a hash as first argument, and an extra C<$chg> argument that can be |
|
|
1316 | ignored: |
1290 | |
1317 | |
1291 | db_mon $group => sub { |
1318 | db_mon $group => sub { |
1292 | my ($ports, $add, $chg, $lde) = @_; |
1319 | my ($ports, $add, $chg, $del) = @_; |
1293 | $ports = [keys %$ports]; |
1320 | $ports = [keys %$ports]; |
1294 | |
1321 | |
1295 | # now $ports, $add and $del are the same as |
1322 | # now $ports, $add and $del are the same as |
1296 | # were originally passed by grp_mon. |
1323 | # were originally passed by grp_mon. |
1297 | ... |
1324 | ... |
… | |
… | |
1311 | of its seed nodes. If that seed node isn't a global node yet, it will |
1338 | of its seed nodes. If that seed node isn't a global node yet, it will |
1312 | automatically be upgraded to a global node. |
1339 | automatically be upgraded to a global node. |
1313 | |
1340 | |
1314 | So in many cases, nothing needs to be changed - one just has to make sure |
1341 | So in many cases, nothing needs to be changed - one just has to make sure |
1315 | that all seed nodes are meshed together with the other seed nodes (as with |
1342 | that all seed nodes are meshed together with the other seed nodes (as with |
1316 | AEMP 1.x), and other nodes specify them as seed nodes. |
1343 | AEMP 1.x), and other nodes specify them as seed nodes. This is most easily |
|
|
1344 | achieved by specifying the same set of seed nodes for all nodes in the |
|
|
1345 | network. |
1317 | |
1346 | |
1318 | Not opening a connection to every other node is usually an advantage, |
1347 | Not opening a connection to every other node is usually an advantage, |
1319 | except when you need the lower latency of an already established |
1348 | except when you need the lower latency of an already established |
1320 | connection. To ensure a node establishes a connection to another node, |
1349 | connection. To ensure a node establishes a connection to another node, |
1321 | you can monitor the node port (C<mon $node, ...>), which will attempt to |
1350 | you can monitor the node port (C<mon $node, ...>), which will attempt to |
1322 | create the connection (and notify you when the connection fails). |
1351 | create the connection (and notify you when the connection fails). |
1323 | |
1352 | |
1324 | =item Listener-less nodes (nodes without binds) are gone. |
1353 | =item Listener-less nodes (nodes without binds) are gone. |
1325 | |
1354 | |
1326 | And are not coming back, at least not in their old form. If no C<binds> |
1355 | And are not coming back, at least not in their old form. If no C<binds> |
1327 | are specified for a node, AnyEvent::MP now assumes a default of C<*:*>. |
1356 | are specified for a node, AnyEvent::MP assumes a default of C<*:*>. |
1328 | |
1357 | |
1329 | There are vague plans to implement some form of routing domains, which |
1358 | There are vague plans to implement some form of routing domains, which |
1330 | might or might not bring back listener-less nodes, but don't count on it. |
1359 | might or might not bring back listener-less nodes, but don't count on it. |
1331 | |
1360 | |
1332 | The fact that most connections are now optional somewhat mitigates this, |
1361 | The fact that most connections are now optional somewhat mitigates this, |
… | |
… | |
1341 | |
1370 | |
1342 | Every module now documents what kinds of messages it generates, with |
1371 | Every module now documents what kinds of messages it generates, with |
1343 | AnyEvent::MP acting as a catch all. |
1372 | AnyEvent::MP acting as a catch all. |
1344 | |
1373 | |
1345 | On the positive side, this means that instead of setting |
1374 | On the positive side, this means that instead of setting |
1346 | C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE>, |
1375 | C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> - |
1347 | much less to type. |
1376 | much less to type. |
1348 | |
1377 | |
1349 | =back |
1378 | =back |
|
|
1379 | |
|
|
1380 | =head1 LOGGING |
|
|
1381 | |
|
|
1382 | AnyEvent::MP does not normally log anything by itself, but since it is the |
|
|
1383 | root of the context hierarchy for AnyEvent::MP modules, it will receive |
|
|
1384 | all log messages by submodules. |
1350 | |
1385 | |
1351 | =head1 SEE ALSO |
1386 | =head1 SEE ALSO |
1352 | |
1387 | |
1353 | L<AnyEvent::MP::Intro> - a gentle introduction. |
1388 | L<AnyEvent::MP::Intro> - a gentle introduction. |
1354 | |
1389 | |