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Revision 1.143 by root, Fri Mar 23 17:54:36 2012 UTC vs.
Revision 1.155 by root, Sat Sep 18 13:46:56 2021 UTC

118each other. To do this, nodes should listen on one or more local transport 118each other. To do this, nodes should listen on one or more local transport
119endpoints - binds. 119endpoints - binds.
120 120
121Currently, only standard C<ip:port> specifications can be used, which 121Currently, only standard C<ip:port> specifications can be used, which
122specify TCP ports to listen on. So a bind is basically just a tcp socket 122specify TCP ports to listen on. So a bind is basically just a tcp socket
123in listening mode thta accepts conenctions form other nodes. 123in listening mode that accepts connections from other nodes.
124 124
125=item seed nodes 125=item seed nodes
126 126
127When a node starts, it knows nothing about the network it is in - it 127When a node starts, it knows nothing about the network it is in - it
128needs to connect to at least one other node that is already in the 128needs to connect to at least one other node that is already in the
129network. These other nodes are called "seed nodes". 129network. These other nodes are called "seed nodes".
130 130
131Seed nodes themselves are not special - they are seed nodes only because 131Seed nodes themselves are not special - they are seed nodes only because
132some other node I<uses> them as such, but any node can be used as seed 132some other node I<uses> them as such, but any node can be used as seed
133node for other nodes, and eahc node cna use a different set of seed nodes. 133node for other nodes, and eahc node can use a different set of seed nodes.
134 134
135In addition to discovering the network, seed nodes are also used to 135In addition to discovering the network, seed nodes are also used to
136maintain the network - all nodes using the same seed node form are part of 136maintain the network - all nodes using the same seed node are part of the
137the same network. If a network is split into multiple subnets because e.g. 137same network. If a network is split into multiple subnets because e.g. the
138the network link between the parts goes down, then using the same seed 138network link between the parts goes down, then using the same seed nodes
139nodes for all nodes ensures that eventually the subnets get merged again. 139for all nodes ensures that eventually the subnets get merged again.
140 140
141Seed nodes are expected to be long-running, and at least one seed node 141Seed nodes are expected to be long-running, and at least one seed node
142should always be available. They should also be relatively responsive - a 142should always be available. They should also be relatively responsive - a
143seed node that blocks for long periods will slow down everybody else. 143seed node that blocks for long periods will slow down everybody else.
144 144
168 168
169Any node that loads the L<AnyEvent::MP::Global> module becomes a global 169Any node that loads the L<AnyEvent::MP::Global> module becomes a global
170node and tries to keep connections to all other nodes. So while it can 170node and tries to keep connections to all other nodes. So while it can
171make sense to make every node "global" in small networks, it usually makes 171make sense to make every node "global" in small networks, it usually makes
172sense to only make seed nodes into global nodes in large networks (nodes 172sense to only make seed nodes into global nodes in large networks (nodes
173keep connections to seed nodes and global nodes, so makign them the same 173keep connections to seed nodes and global nodes, so making them the same
174reduces overhead). 174reduces overhead).
175 175
176=back 176=back
177 177
178=head1 VARIABLES/FUNCTIONS 178=head1 VARIABLES/FUNCTIONS
183 183
184package AnyEvent::MP; 184package AnyEvent::MP;
185 185
186use AnyEvent::MP::Config (); 186use AnyEvent::MP::Config ();
187use AnyEvent::MP::Kernel; 187use AnyEvent::MP::Kernel;
188use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); 188use 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);
189 199
190use common::sense; 200use common::sense;
191 201
192use Carp (); 202use Carp ();
193 203
194use AnyEvent (); 204use AnyEvent ();
195use Guard (); 205use Guard ();
196 206
197use base "Exporter"; 207use base "Exporter";
198 208
199our $VERSION = $AnyEvent::MP::Config::VERSION; 209our $VERSION = '2.02'; # also in MP/Config.pm
200 210
201our @EXPORT = qw( 211our @EXPORT = qw(
202 NODE $NODE *SELF node_of after
203 configure 212 configure
213
214 NODE $NODE
215 *SELF
216
217 node_of port_is_local
218
219 snd kil
204 snd rcv mon mon_guard kil psub peval spawn cal 220 port rcv mon mon_guard psub peval spawn cal
205 port
206 db_set db_del db_reg 221 db_set db_del db_reg
207 db_mon db_family db_keys db_values 222 db_mon db_family db_keys db_values
223
224 after
208); 225);
209 226
210our $SELF; 227our $SELF;
211 228
212sub _self_die() { 229sub _self_die() {
223 240
224=item $nodeid = node_of $port 241=item $nodeid = node_of $port
225 242
226Extracts and returns the node ID from a port ID or a node ID. 243Extracts and returns the node ID from a port ID or a node ID.
227 244
245=item $is_local = port_is_local $port
246
247Returns true iff the port is a local port.
248
228=item configure $profile, key => value... 249=item configure $profile, key => value...
229 250
230=item configure key => value... 251=item configure key => value...
231 252
232Before a node can talk to other nodes on the network (i.e. enter 253Before a node can talk to other nodes on the network (i.e. enter
243=over 4 264=over 4
244 265
245=item norc => $boolean (default false) 266=item norc => $boolean (default false)
246 267
247If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> 268If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
248be consulted - all configuraiton options must be specified in the 269be consulted - all configuration options must be specified in the
249C<configure> call. 270C<configure> call.
250 271
251=item force => $boolean (default false) 272=item force => $boolean (default false)
252 273
253IF true, then the values specified in the C<configure> will take 274IF true, then the values specified in the C<configure> will take
281this process. If not, then the profile name will be used as node ID, with 302this process. If not, then the profile name will be used as node ID, with
282a unique randoms tring (C</%u>) appended. 303a unique randoms tring (C</%u>) appended.
283 304
284The node ID can contain some C<%> sequences that are expanded: C<%n> 305The node ID can contain some C<%> sequences that are expanded: C<%n>
285is expanded to the local nodename, C<%u> is replaced by a random 306is expanded to the local nodename, C<%u> is replaced by a random
286strign to make the node unique. For example, the F<aemp> commandline 307string to make the node unique. For example, the F<aemp> commandline
287utility uses C<aemp/%n/%u> as nodename, which might expand to 308utility uses C<aemp/%n/%u> as nodename, which might expand to
288C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>. 309C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
289 310
290=item step 2, bind listener sockets 311=item step 2, bind listener sockets
291 312
292The next step is to look up the binds in the profile, followed by binding 313The next step is to look up the binds in the profile, followed by binding
293aemp protocol listeners on all binds specified (it is possible and valid 314aemp protocol listeners on all binds specified (it is possible and valid
294to have no binds, meaning that the node cannot be contacted form the 315to have no binds, meaning that the node cannot be contacted from the
295outside. This means the node cannot talk to other nodes that also have no 316outside. This means the node cannot talk to other nodes that also have no
296binds, but it can still talk to all "normal" nodes). 317binds, but it can still talk to all "normal" nodes).
297 318
298If the profile does not specify a binds list, then a default of C<*> is 319If the profile does not specify a binds list, then a default of C<*> is
299used, meaning the node will bind on a dynamically-assigned port on every 320used, meaning the node will bind on a dynamically-assigned port on every
396=cut 417=cut
397 418
398sub rcv($@); 419sub rcv($@);
399 420
400my $KILME = sub { 421my $KILME = sub {
401 (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; 422 (my $tag = substr $_[0], 0, 30) =~ s/([^\x20-\x7e])/./g;
402 kil $SELF, unhandled_message => "no callback found for message '$tag'"; 423 kil $SELF, unhandled_message => "no callback found for message '$tag'";
403}; 424};
404 425
405sub port(;&) { 426sub port(;&) {
406 my $id = $UNIQ . ++$ID; 427 my $id = $UNIQ . ++$ID;
464 485
465sub rcv($@) { 486sub rcv($@) {
466 my $port = shift; 487 my $port = shift;
467 my ($nodeid, $portid) = split /#/, $port, 2; 488 my ($nodeid, $portid) = split /#/, $port, 2;
468 489
469 $NODE{$nodeid} == $NODE{""} 490 $nodeid eq $NODE
470 or Carp::croak "$port: rcv can only be called on local ports, caught"; 491 or Carp::croak "$port: rcv can only be called on local ports, caught";
471 492
472 while (@_) { 493 while (@_) {
473 if (ref $_[0]) { 494 if (ref $_[0]) {
474 if (my $self = $PORT_DATA{$portid}) { 495 if (my $self = $PORT_DATA{$portid}) {
517 $port 538 $port
518} 539}
519 540
520=item peval $port, $coderef[, @args] 541=item peval $port, $coderef[, @args]
521 542
522Evaluates the given C<$codref> within the contetx of C<$port>, that is, 543Evaluates the given C<$codref> within the context of C<$port>, that is,
523when the code throews an exception the C<$port> will be killed. 544when the code throws an exception the C<$port> will be killed.
524 545
525Any remaining args will be passed to the callback. Any return values will 546Any remaining args will be passed to the callback. Any return values will
526be returned to the caller. 547be returned to the caller.
527 548
528This is useful when you temporarily want to execute code in the context of 549This is useful when you temporarily want to execute code in the context of
629In the last form (message), a message of the form C<$rcvport, @msg, 650In the last form (message), a message of the form C<$rcvport, @msg,
630@reason> will be C<snd>. 651@reason> will be C<snd>.
631 652
632Monitoring-actions are one-shot: once messages are lost (and a monitoring 653Monitoring-actions are one-shot: once messages are lost (and a monitoring
633alert was raised), they are removed and will not trigger again, even if it 654alert was raised), they are removed and will not trigger again, even if it
634turns out that the port is still alive. 655turns out that the port is still alive (but monitoring actions added after
656that will again trigger).
635 657
636As a rule of thumb, monitoring requests should always monitor a remote 658As a rule of thumb, monitoring requests should always monitor a remote
637port locally (using a local C<$rcvport> or a callback). The reason is that 659port locally (using a local C<$rcvport> or a callback). The reason is that
638kill messages might get lost, just like any other message. Another less 660kill messages might get lost, just like any other message. Another less
639obvious reason is that even monitoring requests can get lost (for example, 661obvious reason is that even monitoring requests can get lost (for example,
855#=item $cb2 = timeout $seconds, $cb[, @args] 877#=item $cb2 = timeout $seconds, $cb[, @args]
856 878
857=item cal $port, @msg, $callback[, $timeout] 879=item cal $port, @msg, $callback[, $timeout]
858 880
859A simple form of RPC - sends a message to the given C<$port> with the 881A simple form of RPC - sends a message to the given C<$port> with the
860given contents (C<@msg>), but adds a reply port to the message. 882given contents (C<@msg>), but appends a reply port to the message.
861 883
862The reply port is created temporarily just for the purpose of receiving 884The reply port is created temporarily just for the purpose of receiving
863the reply, and will be C<kil>ed when no longer needed. 885the reply, and will be C<kil>ed when no longer needed.
864 886
865A reply message sent to the port is passed to the C<$callback> as-is. 887A reply message sent to the port is passed to the C<$callback> as-is.
1035Same as C<db_family>, except it only queries the family I<values> and passes them 1057Same as C<db_family>, except it only queries the family I<values> and passes them
1036as array reference to the callback. 1058as array reference to the callback.
1037 1059
1038=item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted) 1060=item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
1039 1061
1040Creates a monitor on the given database family. Each time a key is set 1062Creates a monitor on the given database family. Each time a key is
1041or or is deleted the callback is called with a hash containing the 1063set or is deleted the callback is called with a hash containing the
1042database family and three lists of added, changed and deleted subkeys, 1064database family and three lists of added, changed and deleted subkeys,
1043respectively. If no keys have changed then the array reference might be 1065respectively. If no keys have changed then the array reference might be
1044C<undef> or even missing. 1066C<undef> or even missing.
1045 1067
1046If not called in void context, a guard object is returned that, when 1068If not called in void context, a guard object is returned that, when
1074 return unless %$family; 1096 return unless %$family;
1075 undef $guard; 1097 undef $guard;
1076 print "My::Module::workers now nonempty\n"; 1098 print "My::Module::workers now nonempty\n";
1077 }; 1099 };
1078 1100
1079Example: print all changes to the family "AnyRvent::Fantasy::Module". 1101Example: print all changes to the family "AnyEvent::Fantasy::Module".
1080 1102
1081 my $guard = db_mon AnyRvent::Fantasy::Module => sub { 1103 my $guard = db_mon AnyEvent::Fantasy::Module => sub {
1082 my ($family, $a, $c, $d) = @_; 1104 my ($family, $a, $c, $d) = @_;
1083 1105
1084 print "+$_=$family->{$_}\n" for @$a; 1106 print "+$_=$family->{$_}\n" for @$a;
1085 print "*$_=$family->{$_}\n" for @$c; 1107 print "*$_=$family->{$_}\n" for @$c;
1086 print "-$_=$family->{$_}\n" for @$d; 1108 print "-$_=$family->{$_}\n" for @$d;
1137filter messages without dequeuing them. 1159filter messages without dequeuing them.
1138 1160
1139This is not a philosophical difference, but simply stems from AnyEvent::MP 1161This is not a philosophical difference, but simply stems from AnyEvent::MP
1140being event-based, while Erlang is process-based. 1162being event-based, while Erlang is process-based.
1141 1163
1142You cna have a look at L<Coro::MP> for a more Erlang-like process model on 1164You can have a look at L<Coro::MP> for a more Erlang-like process model on
1143top of AEMP and Coro threads. 1165top of AEMP and Coro threads.
1144 1166
1145=item * Erlang sends are synchronous, AEMP sends are asynchronous. 1167=item * Erlang sends are synchronous, AEMP sends are asynchronous.
1146 1168
1147Sending messages in Erlang is synchronous and blocks the process until 1169Sending messages in Erlang is synchronous and blocks the process until
1148a conenction has been established and the message sent (and so does not 1170a connection has been established and the message sent (and so does not
1149need a queue that can overflow). AEMP sends return immediately, connection 1171need a queue that can overflow). AEMP sends return immediately, connection
1150establishment is handled in the background. 1172establishment is handled in the background.
1151 1173
1152=item * Erlang suffers from silent message loss, AEMP does not. 1174=item * Erlang suffers from silent message loss, AEMP does not.
1153 1175
1292C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon> 1314C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
1293passes a hash as first argument, and an extra C<$chg> argument that can be 1315passes a hash as first argument, and an extra C<$chg> argument that can be
1294ignored: 1316ignored:
1295 1317
1296 db_mon $group => sub { 1318 db_mon $group => sub {
1297 my ($ports, $add, $chg, $lde) = @_; 1319 my ($ports, $add, $chg, $del) = @_;
1298 $ports = [keys %$ports]; 1320 $ports = [keys %$ports];
1299 1321
1300 # now $ports, $add and $del are the same as 1322 # now $ports, $add and $del are the same as
1301 # were originally passed by grp_mon. 1323 # were originally passed by grp_mon.
1302 ... 1324 ...
1355 1377
1356=back 1378=back
1357 1379
1358=head1 LOGGING 1380=head1 LOGGING
1359 1381
1360AnyEvent::MP does not normally log anything by itself, but sinc eit is the 1382AnyEvent::MP does not normally log anything by itself, but since it is the
1361root of the contetx hierarchy for AnyEvent::MP modules, it will receive 1383root of the context hierarchy for AnyEvent::MP modules, it will receive
1362all log messages by submodules. 1384all log messages by submodules.
1363 1385
1364=head1 SEE ALSO 1386=head1 SEE ALSO
1365 1387
1366L<AnyEvent::MP::Intro> - a gentle introduction. 1388L<AnyEvent::MP::Intro> - a gentle introduction.

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