… | |
… | |
118 | 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 |
119 | endpoints - binds. |
119 | endpoints - binds. |
120 | |
120 | |
121 | Currently, only standard C<ip:port> specifications can be used, which |
121 | Currently, only standard C<ip:port> specifications can be used, which |
122 | 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 |
123 | in listening mode thta accepts conenctions form other nodes. |
123 | in listening mode that accepts connections from other nodes. |
124 | |
124 | |
125 | =item seed nodes |
125 | =item seed nodes |
126 | |
126 | |
127 | 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 |
128 | 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 |
129 | network. These other nodes are called "seed nodes". |
129 | network. These other nodes are called "seed nodes". |
130 | |
130 | |
131 | 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 |
132 | 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 |
133 | 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. |
134 | |
134 | |
135 | 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 |
136 | 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 |
137 | 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 |
138 | 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 |
139 | nodes for all nodes ensures that eventually the subnets get merged again. |
139 | for all nodes ensures that eventually the subnets get merged again. |
140 | |
140 | |
141 | 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 |
142 | should always be available. They should also be relatively responsive - a |
142 | should always be available. They should also be relatively responsive - a |
143 | 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. |
144 | |
144 | |
… | |
… | |
168 | |
168 | |
169 | 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 |
170 | 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 |
171 | 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 |
172 | 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 |
173 | 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 |
174 | reduces overhead). |
174 | reduces overhead). |
175 | |
175 | |
176 | =back |
176 | =back |
177 | |
177 | |
178 | =head1 VARIABLES/FUNCTIONS |
178 | =head1 VARIABLES/FUNCTIONS |
… | |
… | |
204 | use AnyEvent (); |
204 | use AnyEvent (); |
205 | use Guard (); |
205 | use Guard (); |
206 | |
206 | |
207 | use base "Exporter"; |
207 | use base "Exporter"; |
208 | |
208 | |
209 | our $VERSION = $AnyEvent::MP::Config::VERSION; |
209 | our $VERSION = '2.02'; # also in MP/Config.pm |
210 | |
210 | |
211 | our @EXPORT = qw( |
211 | our @EXPORT = qw( |
|
|
212 | configure |
|
|
213 | |
212 | NODE $NODE |
214 | NODE $NODE |
213 | configure |
215 | *SELF |
|
|
216 | |
214 | node_of port_is_local |
217 | node_of port_is_local |
|
|
218 | |
215 | snd kil |
219 | snd kil |
216 | db_set db_del |
|
|
217 | db_mon db_family db_keys db_values |
|
|
218 | |
|
|
219 | *SELF |
|
|
220 | |
|
|
221 | port rcv mon mon_guard psub peval spawn cal |
220 | port rcv mon mon_guard psub peval spawn cal |
222 | db_set db_del db_reg |
221 | db_set db_del db_reg |
223 | db_mon db_family db_keys db_values |
222 | db_mon db_family db_keys db_values |
224 | |
223 | |
225 | after |
224 | after |
… | |
… | |
303 | 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 |
304 | a unique randoms tring (C</%u>) appended. |
303 | a unique randoms tring (C</%u>) appended. |
305 | |
304 | |
306 | 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> |
307 | 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 |
308 | 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 |
309 | 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 |
310 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
309 | C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. |
311 | |
310 | |
312 | =item step 2, bind listener sockets |
311 | =item step 2, bind listener sockets |
313 | |
312 | |
314 | 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 |
315 | 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 |
316 | 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 |
317 | 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 |
318 | binds, but it can still talk to all "normal" nodes). |
317 | binds, but it can still talk to all "normal" nodes). |
319 | |
318 | |
320 | 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 |
321 | 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 |
… | |
… | |
418 | =cut |
417 | =cut |
419 | |
418 | |
420 | sub rcv($@); |
419 | sub rcv($@); |
421 | |
420 | |
422 | my $KILME = sub { |
421 | my $KILME = sub { |
423 | (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; |
422 | (my $tag = substr $_[0], 0, 30) =~ s/([^\x20-\x7e])/./g; |
424 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
423 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
425 | }; |
424 | }; |
426 | |
425 | |
427 | sub port(;&) { |
426 | sub port(;&) { |
428 | my $id = $UNIQ . ++$ID; |
427 | my $id = $UNIQ . ++$ID; |
… | |
… | |
539 | $port |
538 | $port |
540 | } |
539 | } |
541 | |
540 | |
542 | =item peval $port, $coderef[, @args] |
541 | =item peval $port, $coderef[, @args] |
543 | |
542 | |
544 | Evaluates the given C<$codref> within the contetx of C<$port>, that is, |
543 | Evaluates the given C<$codref> within the context of C<$port>, that is, |
545 | when the code throws an exception the C<$port> will be killed. |
544 | when the code throws an exception the C<$port> will be killed. |
546 | |
545 | |
547 | Any remaining args will be passed to the callback. Any return values will |
546 | Any remaining args will be passed to the callback. Any return values will |
548 | be returned to the caller. |
547 | be returned to the caller. |
549 | |
548 | |
… | |
… | |
651 | In the last form (message), a message of the form C<$rcvport, @msg, |
650 | In the last form (message), a message of the form C<$rcvport, @msg, |
652 | @reason> will be C<snd>. |
651 | @reason> will be C<snd>. |
653 | |
652 | |
654 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
653 | Monitoring-actions are one-shot: once messages are lost (and a monitoring |
655 | alert was raised), they are removed and will not trigger again, even if it |
654 | alert was raised), they are removed and will not trigger again, even if it |
656 | turns out that the port is still alive. |
655 | turns out that the port is still alive (but monitoring actions added after |
|
|
656 | that will again trigger). |
657 | |
657 | |
658 | As a rule of thumb, monitoring requests should always monitor a remote |
658 | As a rule of thumb, monitoring requests should always monitor a remote |
659 | port locally (using a local C<$rcvport> or a callback). The reason is that |
659 | port locally (using a local C<$rcvport> or a callback). The reason is that |
660 | kill messages might get lost, just like any other message. Another less |
660 | kill messages might get lost, just like any other message. Another less |
661 | obvious reason is that even monitoring requests can get lost (for example, |
661 | obvious reason is that even monitoring requests can get lost (for example, |
… | |
… | |
877 | #=item $cb2 = timeout $seconds, $cb[, @args] |
877 | #=item $cb2 = timeout $seconds, $cb[, @args] |
878 | |
878 | |
879 | =item cal $port, @msg, $callback[, $timeout] |
879 | =item cal $port, @msg, $callback[, $timeout] |
880 | |
880 | |
881 | A simple form of RPC - sends a message to the given C<$port> with the |
881 | A simple form of RPC - sends a message to the given C<$port> with the |
882 | given contents (C<@msg>), but adds a reply port to the message. |
882 | given contents (C<@msg>), but appends a reply port to the message. |
883 | |
883 | |
884 | The reply port is created temporarily just for the purpose of receiving |
884 | The reply port is created temporarily just for the purpose of receiving |
885 | the reply, and will be C<kil>ed when no longer needed. |
885 | the reply, and will be C<kil>ed when no longer needed. |
886 | |
886 | |
887 | A reply message sent to the port is passed to the C<$callback> as-is. |
887 | A reply message sent to the port is passed to the C<$callback> as-is. |
… | |
… | |
1057 | 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 |
1058 | as array reference to the callback. |
1058 | as array reference to the callback. |
1059 | |
1059 | |
1060 | =item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted) |
1060 | =item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted) |
1061 | |
1061 | |
1062 | Creates a monitor on the given database family. Each time a key is set |
1062 | Creates a monitor on the given database family. Each time a key is |
1063 | or or is deleted the callback is called with a hash containing the |
1063 | set or is deleted the callback is called with a hash containing the |
1064 | database family and three lists of added, changed and deleted subkeys, |
1064 | database family and three lists of added, changed and deleted subkeys, |
1065 | respectively. If no keys have changed then the array reference might be |
1065 | respectively. If no keys have changed then the array reference might be |
1066 | C<undef> or even missing. |
1066 | C<undef> or even missing. |
1067 | |
1067 | |
1068 | If not called in void context, a guard object is returned that, when |
1068 | If not called in void context, a guard object is returned that, when |
… | |
… | |
1096 | return unless %$family; |
1096 | return unless %$family; |
1097 | undef $guard; |
1097 | undef $guard; |
1098 | print "My::Module::workers now nonempty\n"; |
1098 | print "My::Module::workers now nonempty\n"; |
1099 | }; |
1099 | }; |
1100 | |
1100 | |
1101 | Example: print all changes to the family "AnyRvent::Fantasy::Module". |
1101 | Example: print all changes to the family "AnyEvent::Fantasy::Module". |
1102 | |
1102 | |
1103 | my $guard = db_mon AnyRvent::Fantasy::Module => sub { |
1103 | my $guard = db_mon AnyEvent::Fantasy::Module => sub { |
1104 | my ($family, $a, $c, $d) = @_; |
1104 | my ($family, $a, $c, $d) = @_; |
1105 | |
1105 | |
1106 | print "+$_=$family->{$_}\n" for @$a; |
1106 | print "+$_=$family->{$_}\n" for @$a; |
1107 | print "*$_=$family->{$_}\n" for @$c; |
1107 | print "*$_=$family->{$_}\n" for @$c; |
1108 | print "-$_=$family->{$_}\n" for @$d; |
1108 | print "-$_=$family->{$_}\n" for @$d; |
… | |
… | |
1159 | filter messages without dequeuing them. |
1159 | filter messages without dequeuing them. |
1160 | |
1160 | |
1161 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
1161 | This is not a philosophical difference, but simply stems from AnyEvent::MP |
1162 | being event-based, while Erlang is process-based. |
1162 | being event-based, while Erlang is process-based. |
1163 | |
1163 | |
1164 | You cna have a look at L<Coro::MP> for a more Erlang-like process model on |
1164 | You can have a look at L<Coro::MP> for a more Erlang-like process model on |
1165 | top of AEMP and Coro threads. |
1165 | top of AEMP and Coro threads. |
1166 | |
1166 | |
1167 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
1167 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
1168 | |
1168 | |
1169 | Sending messages in Erlang is synchronous and blocks the process until |
1169 | Sending messages in Erlang is synchronous and blocks the process until |
1170 | a conenction has been established and the message sent (and so does not |
1170 | a connection has been established and the message sent (and so does not |
1171 | need a queue that can overflow). AEMP sends return immediately, connection |
1171 | need a queue that can overflow). AEMP sends return immediately, connection |
1172 | establishment is handled in the background. |
1172 | establishment is handled in the background. |
1173 | |
1173 | |
1174 | =item * Erlang suffers from silent message loss, AEMP does not. |
1174 | =item * Erlang suffers from silent message loss, AEMP does not. |
1175 | |
1175 | |
… | |
… | |
1314 | C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon> |
1314 | C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon> |
1315 | passes a hash as first argument, and an extra C<$chg> argument that can be |
1315 | passes a hash as first argument, and an extra C<$chg> argument that can be |
1316 | ignored: |
1316 | ignored: |
1317 | |
1317 | |
1318 | db_mon $group => sub { |
1318 | db_mon $group => sub { |
1319 | my ($ports, $add, $chg, $lde) = @_; |
1319 | my ($ports, $add, $chg, $del) = @_; |
1320 | $ports = [keys %$ports]; |
1320 | $ports = [keys %$ports]; |
1321 | |
1321 | |
1322 | # now $ports, $add and $del are the same as |
1322 | # now $ports, $add and $del are the same as |
1323 | # were originally passed by grp_mon. |
1323 | # were originally passed by grp_mon. |
1324 | ... |
1324 | ... |
… | |
… | |
1377 | |
1377 | |
1378 | =back |
1378 | =back |
1379 | |
1379 | |
1380 | =head1 LOGGING |
1380 | =head1 LOGGING |
1381 | |
1381 | |
1382 | AnyEvent::MP does not normally log anything by itself, but sinc eit is the |
1382 | AnyEvent::MP does not normally log anything by itself, but since it is the |
1383 | root of the contetx hierarchy for AnyEvent::MP modules, it will receive |
1383 | root of the context hierarchy for AnyEvent::MP modules, it will receive |
1384 | all log messages by submodules. |
1384 | all log messages by submodules. |
1385 | |
1385 | |
1386 | =head1 SEE ALSO |
1386 | =head1 SEE ALSO |
1387 | |
1387 | |
1388 | L<AnyEvent::MP::Intro> - a gentle introduction. |
1388 | L<AnyEvent::MP::Intro> - a gentle introduction. |