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Revision 1.141 by root, Fri Mar 23 03:24:41 2012 UTC vs.
Revision 1.148 by root, Mon Jun 20 16:58:30 2016 UTC

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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 # 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
56
57 # distributed database - queries
58 db_family $family => $cb->(\%familyhash)
59 db_keys $family => $cb->(\@keys)
60 db_values $family => $cb->(\@values)
61
62 # distributed database - monitoring a family
63 db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
64
52=head1 DESCRIPTION 65=head1 DESCRIPTION
53 66
54This module (-family) implements a simple message passing framework. 67This module (-family) implements a simple message passing framework.
55 68
56Despite its simplicity, you can securely message other processes running 69Despite its simplicity, you can securely message other processes running
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105each 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
106endpoints - binds. 119endpoints - binds.
107 120
108Currently, only standard C<ip:port> specifications can be used, which 121Currently, only standard C<ip:port> specifications can be used, which
109specify 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
110in listening mode thta accepts conenctions form other nodes. 123in listening mode that accepts connections from other nodes.
111 124
112=item seed nodes 125=item seed nodes
113 126
114When 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
115needs 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
116network. These other nodes are called "seed nodes". 129network. These other nodes are called "seed nodes".
117 130
118Seed nodes themselves are not special - they are seed nodes only because 131Seed nodes themselves are not special - they are seed nodes only because
119some 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
120node 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.
121 134
122In addition to discovering the network, seed nodes are also used to 135In addition to discovering the network, seed nodes are also used to
123maintain 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
124the 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
125the 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
126nodes for all nodes ensures that eventually the subnets get merged again. 139for all nodes ensures that eventually the subnets get merged again.
127 140
128Seed 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
129should always be available. They should also be relatively responsive - a 142should always be available. They should also be relatively responsive - a
130seed node that blocks for long periods will slow down everybody else. 143seed node that blocks for long periods will slow down everybody else.
131 144
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155 168
156Any 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
157node 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
158make 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
159sense 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
160keep 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
161reduces overhead). 174reduces overhead).
162 175
163=back 176=back
164 177
165=head1 VARIABLES/FUNCTIONS 178=head1 VARIABLES/FUNCTIONS
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170 183
171package AnyEvent::MP; 184package AnyEvent::MP;
172 185
173use AnyEvent::MP::Config (); 186use AnyEvent::MP::Config ();
174use AnyEvent::MP::Kernel; 187use AnyEvent::MP::Kernel;
175use 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);
176 199
177use common::sense; 200use common::sense;
178 201
179use Carp (); 202use Carp ();
180 203
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184use base "Exporter"; 207use base "Exporter";
185 208
186our $VERSION = $AnyEvent::MP::Config::VERSION; 209our $VERSION = $AnyEvent::MP::Config::VERSION;
187 210
188our @EXPORT = qw( 211our @EXPORT = qw(
189 NODE $NODE *SELF node_of after 212 NODE $NODE
190 configure 213 configure
214 node_of port_is_local
215 snd kil
216 db_set db_del
217 db_mon db_family db_keys db_values
218
219 *SELF
220
191 snd rcv mon mon_guard kil psub peval spawn cal 221 port rcv mon mon_guard psub peval spawn cal
192 port
193 db_set db_del db_reg 222 db_set db_del db_reg
194 db_mon db_family db_keys db_values 223 db_mon db_family db_keys db_values
224
225 after
195); 226);
196 227
197our $SELF; 228our $SELF;
198 229
199sub _self_die() { 230sub _self_die() {
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210 241
211=item $nodeid = node_of $port 242=item $nodeid = node_of $port
212 243
213Extracts and returns the node ID from a port ID or a node ID. 244Extracts and returns the node ID from a port ID or a node ID.
214 245
246=item $is_local = port_is_local $port
247
248Returns true iff the port is a local port.
249
215=item configure $profile, key => value... 250=item configure $profile, key => value...
216 251
217=item configure key => value... 252=item configure key => value...
218 253
219Before a node can talk to other nodes on the network (i.e. enter 254Before a node can talk to other nodes on the network (i.e. enter
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230=over 4 265=over 4
231 266
232=item norc => $boolean (default false) 267=item norc => $boolean (default false)
233 268
234If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> 269If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
235be consulted - all configuraiton options must be specified in the 270be consulted - all configuration options must be specified in the
236C<configure> call. 271C<configure> call.
237 272
238=item force => $boolean (default false) 273=item force => $boolean (default false)
239 274
240IF true, then the values specified in the C<configure> will take 275IF true, then the values specified in the C<configure> will take
241precedence over any values configured via the rc file. The default is for 276precedence over any values configured via the rc file. The default is for
242the rc file to override any options specified in the program. 277the rc file to override any options specified in the program.
243
244=item secure => $pass->(@msg)
245
246In addition to specifying a boolean, you can specify a code reference that
247is called for every code execution attempt - the execution request is
248granted iff the callback returns a true value.
249
250Most of the time the callback should look only at
251C<$AnyEvent::MP::Kernel::SRCNODE> to make a decision, and not at the
252actual message (which can be about anything, and is mostly provided for
253diagnostic purposes).
254
255See F<semp setsecure> for more info.
256 278
257=back 279=back
258 280
259=over 4 281=over 4
260 282
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289 311
290=item step 2, bind listener sockets 312=item step 2, bind listener sockets
291 313
292The next step is to look up the binds in the profile, followed by binding 314The 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 315aemp protocol listeners on all binds specified (it is possible and valid
294to have no binds, meaning that the node cannot be contacted form the 316to 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 317outside. This means the node cannot talk to other nodes that also have no
296binds, but it can still talk to all "normal" nodes). 318binds, but it can still talk to all "normal" nodes).
297 319
298If the profile does not specify a binds list, then a default of C<*> is 320If 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 321used, meaning the node will bind on a dynamically-assigned port on every
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464 486
465sub rcv($@) { 487sub rcv($@) {
466 my $port = shift; 488 my $port = shift;
467 my ($nodeid, $portid) = split /#/, $port, 2; 489 my ($nodeid, $portid) = split /#/, $port, 2;
468 490
469 $NODE{$nodeid} == $NODE{""} 491 $nodeid eq $NODE
470 or Carp::croak "$port: rcv can only be called on local ports, caught"; 492 or Carp::croak "$port: rcv can only be called on local ports, caught";
471 493
472 while (@_) { 494 while (@_) {
473 if (ref $_[0]) { 495 if (ref $_[0]) {
474 if (my $self = $PORT_DATA{$portid}) { 496 if (my $self = $PORT_DATA{$portid}) {
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518} 540}
519 541
520=item peval $port, $coderef[, @args] 542=item peval $port, $coderef[, @args]
521 543
522Evaluates the given C<$codref> within the contetx of C<$port>, that is, 544Evaluates the given C<$codref> within the contetx of C<$port>, that is,
523when the code throews an exception the C<$port> will be killed. 545when the code throws an exception the C<$port> will be killed.
524 546
525Any remaining args will be passed to the callback. Any return values will 547Any remaining args will be passed to the callback. Any return values will
526be returned to the caller. 548be returned to the caller.
527 549
528This is useful when you temporarily want to execute code in the context of 550This is useful when you temporarily want to execute code in the context of
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1033=item db_values $family => $cb->(\@values) 1055=item db_values $family => $cb->(\@values)
1034 1056
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 => $cb->(\%familyhash, \@added, \@changed, \@deleted)
1039 1061
1040Creates a monitor on the given database family. Each time a key is set 1062Creates a monitor on the given database family. Each time a key is
1041or or is deleted the callback is called with a hash containing the 1063set or is deleted the callback is called with a hash containing the
1042database family and three lists of added, changed and deleted subkeys, 1064database family and three lists of added, changed and deleted subkeys,
1043respectively. If no keys have changed then the array reference might be 1065respectively. If no keys have changed then the array reference might be
1044C<undef> or even missing. 1066C<undef> or even missing.
1045 1067
1046If not called in void context, a guard object is returned that, when 1068If not called in void context, a guard object is returned that, when
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1074 return unless %$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;
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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
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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 contetx 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

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