… | |
… | |
8 | |
8 | |
9 | $NODE # contains this node's noderef |
9 | $NODE # contains this node's noderef |
10 | NODE # returns this node's noderef |
10 | NODE # returns this node's noderef |
11 | NODE $port # returns the noderef of the port |
11 | NODE $port # returns the noderef of the port |
12 | |
12 | |
|
|
13 | $SELF # receiving/own port id in rcv callbacks |
|
|
14 | |
|
|
15 | # initialise the node so it can send/receive messages |
|
|
16 | initialise_node; # -OR- |
|
|
17 | initialise_node "localhost:4040"; # -OR- |
|
|
18 | initialise_node "slave/", "localhost:4040" |
|
|
19 | |
|
|
20 | # ports are message endpoints |
|
|
21 | |
|
|
22 | # sending messages |
13 | snd $port, type => data...; |
23 | snd $port, type => data...; |
|
|
24 | snd $port, @msg; |
|
|
25 | snd @msg_with_first_element_being_a_port; |
14 | |
26 | |
15 | $SELF # receiving/own port id in rcv callbacks |
27 | # creating/using ports, the simple way |
|
|
28 | my $somple_port = port { my @msg = @_; 0 }; |
16 | |
29 | |
17 | rcv $port, smartmatch => $cb->($port, @msg); |
30 | # creating/using ports, type matching |
18 | |
31 | my $port = port; |
19 | # examples: |
|
|
20 | rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; |
32 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
21 | rcv $port1, pong => sub { warn "pong received\n" }; |
33 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
22 | snd $port2, ping => $port1; |
|
|
23 | |
34 | |
24 | # more, smarter, matches (_any_ is exported by this module) |
35 | # create a port on another node |
25 | rcv $port, [child_died => $pid] => sub { ... |
36 | my $port = spawn $node, $initfunc, @initdata; |
26 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
37 | |
|
|
38 | # monitoring |
|
|
39 | mon $port, $cb->(@msg) # callback is invoked on death |
|
|
40 | mon $port, $otherport # kill otherport on abnormal death |
|
|
41 | mon $port, $otherport, @msg # send message on death |
|
|
42 | |
|
|
43 | =head1 CURRENT STATUS |
|
|
44 | |
|
|
45 | AnyEvent::MP - stable API, should work |
|
|
46 | AnyEvent::MP::Intro - outdated |
|
|
47 | AnyEvent::MP::Kernel - WIP |
|
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48 | AnyEvent::MP::Transport - mostly stable |
|
|
49 | |
|
|
50 | stay tuned. |
27 | |
51 | |
28 | =head1 DESCRIPTION |
52 | =head1 DESCRIPTION |
29 | |
53 | |
30 | This module (-family) implements a simple message passing framework. |
54 | This module (-family) implements a simple message passing framework. |
31 | |
55 | |
… | |
… | |
35 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
59 | For an introduction to this module family, see the L<AnyEvent::MP::Intro> |
36 | manual page. |
60 | manual page. |
37 | |
61 | |
38 | At the moment, this module family is severly broken and underdocumented, |
62 | At the moment, this module family is severly broken and underdocumented, |
39 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
63 | so do not use. This was uploaded mainly to reserve the CPAN namespace - |
40 | stay tuned! The basic API should be finished, however. |
64 | stay tuned! |
41 | |
65 | |
42 | =head1 CONCEPTS |
66 | =head1 CONCEPTS |
43 | |
67 | |
44 | =over 4 |
68 | =over 4 |
45 | |
69 | |
… | |
… | |
53 | |
77 | |
54 | =item port id - C<noderef#portname> |
78 | =item port id - C<noderef#portname> |
55 | |
79 | |
56 | A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as |
80 | A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as |
57 | separator, and a port name (a printable string of unspecified format). An |
81 | separator, and a port name (a printable string of unspecified format). An |
58 | exception is the the node port, whose ID is identical to it's node |
82 | exception is the the node port, whose ID is identical to its node |
59 | reference. |
83 | reference. |
60 | |
84 | |
61 | =item node |
85 | =item node |
62 | |
86 | |
63 | A node is a single process containing at least one port - the node |
87 | A node is a single process containing at least one port - the node |
… | |
… | |
90 | |
114 | |
91 | =cut |
115 | =cut |
92 | |
116 | |
93 | package AnyEvent::MP; |
117 | package AnyEvent::MP; |
94 | |
118 | |
95 | use AnyEvent::MP::Base; |
119 | use AnyEvent::MP::Kernel; |
96 | |
120 | |
97 | use common::sense; |
121 | use common::sense; |
98 | |
122 | |
99 | use Carp (); |
123 | use Carp (); |
100 | |
124 | |
101 | use AE (); |
125 | use AE (); |
102 | |
126 | |
103 | use base "Exporter"; |
127 | use base "Exporter"; |
104 | |
128 | |
105 | our $VERSION = '0.1'; |
129 | our $VERSION = $AnyEvent::MP::Kernel::VERSION; |
|
|
130 | |
106 | our @EXPORT = qw( |
131 | our @EXPORT = qw( |
107 | NODE $NODE *SELF node_of _any_ |
132 | NODE $NODE *SELF node_of _any_ |
108 | resolve_node |
133 | resolve_node initialise_node |
109 | become_slave become_public |
|
|
110 | snd rcv mon kil reg psub |
134 | snd rcv mon kil reg psub spawn |
111 | port |
135 | port |
112 | ); |
136 | ); |
113 | |
137 | |
114 | our $SELF; |
138 | our $SELF; |
115 | |
139 | |
… | |
… | |
124 | The C<NODE> function returns, and the C<$NODE> variable contains |
148 | The C<NODE> function returns, and the C<$NODE> variable contains |
125 | the noderef of the local node. The value is initialised by a call |
149 | the noderef of the local node. The value is initialised by a call |
126 | to C<become_public> or C<become_slave>, after which all local port |
150 | to C<become_public> or C<become_slave>, after which all local port |
127 | identifiers become invalid. |
151 | identifiers become invalid. |
128 | |
152 | |
129 | =item $noderef = node_of $portid |
153 | =item $noderef = node_of $port |
130 | |
154 | |
131 | Extracts and returns the noderef from a portid or a noderef. |
155 | Extracts and returns the noderef from a portid or a noderef. |
|
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156 | |
|
|
157 | =item initialise_node $noderef, $seednode, $seednode... |
|
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158 | |
|
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159 | =item initialise_node "slave/", $master, $master... |
|
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160 | |
|
|
161 | Before a node can talk to other nodes on the network it has to initialise |
|
|
162 | itself - the minimum a node needs to know is it's own name, and optionally |
|
|
163 | it should know the noderefs of some other nodes in the network. |
|
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164 | |
|
|
165 | This function initialises a node - it must be called exactly once (or |
|
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166 | never) before calling other AnyEvent::MP functions. |
|
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167 | |
|
|
168 | All arguments (optionally except for the first) are noderefs, which can be |
|
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169 | either resolved or unresolved. |
|
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170 | |
|
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171 | The first argument will be looked up in the configuration database first |
|
|
172 | (if it is C<undef> then the current nodename will be used instead) to find |
|
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173 | the relevant configuration profile (see L<aemp>). If none is found then |
|
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174 | the default configuration is used. The configuration supplies additional |
|
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175 | seed/master nodes and can override the actual noderef. |
|
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176 | |
|
|
177 | There are two types of networked nodes, public nodes and slave nodes: |
|
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178 | |
|
|
179 | =over 4 |
|
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180 | |
|
|
181 | =item public nodes |
|
|
182 | |
|
|
183 | For public nodes, C<$noderef> (supplied either directly to |
|
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184 | C<initialise_node> or indirectly via a profile or the nodename) must be a |
|
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185 | noderef (possibly unresolved, in which case it will be resolved). |
|
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186 | |
|
|
187 | After resolving, the node will bind itself on all endpoints and try to |
|
|
188 | connect to all additional C<$seednodes> that are specified. Seednodes are |
|
|
189 | optional and can be used to quickly bootstrap the node into an existing |
|
|
190 | network. |
|
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191 | |
|
|
192 | =item slave nodes |
|
|
193 | |
|
|
194 | When the C<$noderef> (either as given or overriden by the config file) |
|
|
195 | is the special string C<slave/>, then the node will become a slave |
|
|
196 | node. Slave nodes cannot be contacted from outside and will route most of |
|
|
197 | their traffic to the master node that they attach to. |
|
|
198 | |
|
|
199 | At least one additional noderef is required (either by specifying it |
|
|
200 | directly or because it is part of the configuration profile): The node |
|
|
201 | will try to connect to all of them and will become a slave attached to the |
|
|
202 | first node it can successfully connect to. |
|
|
203 | |
|
|
204 | =back |
|
|
205 | |
|
|
206 | This function will block until all nodes have been resolved and, for slave |
|
|
207 | nodes, until it has successfully established a connection to a master |
|
|
208 | server. |
|
|
209 | |
|
|
210 | Example: become a public node listening on the guessed noderef, or the one |
|
|
211 | specified via C<aemp> for the current node. This should be the most common |
|
|
212 | form of invocation for "daemon"-type nodes. |
|
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213 | |
|
|
214 | initialise_node; |
|
|
215 | |
|
|
216 | Example: become a slave node to any of the the seednodes specified via |
|
|
217 | C<aemp>. This form is often used for commandline clients. |
|
|
218 | |
|
|
219 | initialise_node "slave/"; |
|
|
220 | |
|
|
221 | Example: become a slave node to any of the specified master servers. This |
|
|
222 | form is also often used for commandline clients. |
|
|
223 | |
|
|
224 | initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net"; |
|
|
225 | |
|
|
226 | Example: become a public node, and try to contact some well-known master |
|
|
227 | servers to become part of the network. |
|
|
228 | |
|
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229 | initialise_node undef, "master1", "master2"; |
|
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230 | |
|
|
231 | Example: become a public node listening on port C<4041>. |
|
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232 | |
|
|
233 | initialise_node 4041; |
|
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234 | |
|
|
235 | Example: become a public node, only visible on localhost port 4044. |
|
|
236 | |
|
|
237 | initialise_node "localhost:4044"; |
132 | |
238 | |
133 | =item $cv = resolve_node $noderef |
239 | =item $cv = resolve_node $noderef |
134 | |
240 | |
135 | Takes an unresolved node reference that may contain hostnames and |
241 | Takes an unresolved node reference that may contain hostnames and |
136 | abbreviated IDs, resolves all of them and returns a resolved node |
242 | abbreviated IDs, resolves all of them and returns a resolved node |
… | |
… | |
168 | |
274 | |
169 | Due to some quirks in how perl exports variables, it is impossible to |
275 | Due to some quirks in how perl exports variables, it is impossible to |
170 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
276 | just export C<$SELF>, all the symbols called C<SELF> are exported by this |
171 | module, but only C<$SELF> is currently used. |
277 | module, but only C<$SELF> is currently used. |
172 | |
278 | |
173 | =item snd $portid, type => @data |
279 | =item snd $port, type => @data |
174 | |
280 | |
175 | =item snd $portid, @msg |
281 | =item snd $port, @msg |
176 | |
282 | |
177 | Send the given message to the given port ID, which can identify either |
283 | Send the given message to the given port ID, which can identify either |
178 | a local or a remote port, and can be either a string or soemthignt hat |
284 | a local or a remote port, and can be either a string or soemthignt hat |
179 | stringifies a sa port ID (such as a port object :). |
285 | stringifies a sa port ID (such as a port object :). |
180 | |
286 | |
… | |
… | |
190 | JSON is used, then only strings, numbers and arrays and hashes consisting |
296 | JSON is used, then only strings, numbers and arrays and hashes consisting |
191 | of those are allowed (no objects). When Storable is used, then anything |
297 | of those are allowed (no objects). When Storable is used, then anything |
192 | that Storable can serialise and deserialise is allowed, and for the local |
298 | that Storable can serialise and deserialise is allowed, and for the local |
193 | node, anything can be passed. |
299 | node, anything can be passed. |
194 | |
300 | |
195 | =item kil $portid[, @reason] |
301 | =item $local_port = port |
196 | |
302 | |
197 | Kill the specified port with the given C<@reason>. |
303 | Create a new local port object and returns its port ID. Initially it has |
|
|
304 | no callbacks set and will throw an error when it receives messages. |
198 | |
305 | |
199 | If no C<@reason> is specified, then the port is killed "normally" (linked |
306 | =item $local_port = port { my @msg = @_ } |
200 | ports will not be kileld, or even notified). |
|
|
201 | |
307 | |
202 | Otherwise, linked ports get killed with the same reason (second form of |
308 | Creates a new local port, and returns its ID. Semantically the same as |
203 | C<mon>, see below). |
309 | creating a port and calling C<rcv $port, $callback> on it. |
204 | |
310 | |
205 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
311 | The block will be called for every message received on the port, with the |
206 | will be reported as reason C<< die => $@ >>. |
312 | global variable C<$SELF> set to the port ID. Runtime errors will cause the |
|
|
313 | port to be C<kil>ed. The message will be passed as-is, no extra argument |
|
|
314 | (i.e. no port ID) will be passed to the callback. |
207 | |
315 | |
208 | Transport/communication errors are reported as C<< transport_error => |
316 | If you want to stop/destroy the port, simply C<kil> it: |
209 | $message >>. |
|
|
210 | |
317 | |
211 | =item $guard = mon $portid, $cb->(@reason) |
318 | my $port = port { |
212 | |
|
|
213 | =item $guard = mon $portid, $otherport |
|
|
214 | |
|
|
215 | =item $guard = mon $portid, $otherport, @msg |
|
|
216 | |
|
|
217 | Monitor the given port and do something when the port is killed. |
|
|
218 | |
|
|
219 | In the first form, the callback is simply called with any number |
|
|
220 | of C<@reason> elements (no @reason means that the port was deleted |
|
|
221 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
|
|
222 | C<eval> if unsure. |
|
|
223 | |
|
|
224 | In the second form, the other port will be C<kil>'ed with C<@reason>, iff |
|
|
225 | a @reason was specified, i.e. on "normal" kils nothing happens, while |
|
|
226 | under all other conditions, the other port is killed with the same reason. |
|
|
227 | |
|
|
228 | In the last form, a message of the form C<@msg, @reason> will be C<snd>. |
|
|
229 | |
|
|
230 | Example: call a given callback when C<$port> is killed. |
|
|
231 | |
|
|
232 | mon $port, sub { warn "port died because of <@_>\n" }; |
|
|
233 | |
|
|
234 | Example: kill ourselves when C<$port> is killed abnormally. |
|
|
235 | |
|
|
236 | mon $port, $self; |
|
|
237 | |
|
|
238 | Example: send us a restart message another C<$port> is killed. |
|
|
239 | |
|
|
240 | mon $port, $self => "restart"; |
|
|
241 | |
|
|
242 | =cut |
|
|
243 | |
|
|
244 | sub mon { |
|
|
245 | my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift); |
|
|
246 | |
|
|
247 | my $node = $NODE{$noderef} || add_node $noderef; |
|
|
248 | |
|
|
249 | #TODO: ports must not be references |
|
|
250 | if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) { |
|
|
251 | if (@_) { |
|
|
252 | # send a kill info message |
|
|
253 | my (@msg) = ($cb, @_); |
319 | my @msg = @_; |
254 | $cb = sub { snd @msg, @_ }; |
|
|
255 | } else { |
|
|
256 | # simply kill other port |
|
|
257 | my $port = $cb; |
|
|
258 | $cb = sub { kil $port, @_ if @_ }; |
|
|
259 | } |
320 | ... |
|
|
321 | kil $SELF; |
260 | } |
322 | }; |
261 | |
323 | |
262 | $node->monitor ($port, $cb); |
324 | =cut |
263 | |
325 | |
264 | defined wantarray |
326 | sub rcv($@); |
265 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
327 | |
|
|
328 | sub _kilme { |
|
|
329 | die "received message on port without callback"; |
266 | } |
330 | } |
267 | |
|
|
268 | =item $guard = mon_guard $port, $ref, $ref... |
|
|
269 | |
|
|
270 | Monitors the given C<$port> and keeps the passed references. When the port |
|
|
271 | is killed, the references will be freed. |
|
|
272 | |
|
|
273 | Optionally returns a guard that will stop the monitoring. |
|
|
274 | |
|
|
275 | This function is useful when you create e.g. timers or other watchers and |
|
|
276 | want to free them when the port gets killed: |
|
|
277 | |
|
|
278 | $port->rcv (start => sub { |
|
|
279 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
|
|
280 | undef $timer if 0.9 < rand; |
|
|
281 | }); |
|
|
282 | }); |
|
|
283 | |
|
|
284 | =cut |
|
|
285 | |
|
|
286 | sub mon_guard { |
|
|
287 | my ($port, @refs) = @_; |
|
|
288 | |
|
|
289 | mon $port, sub { 0 && @refs } |
|
|
290 | } |
|
|
291 | |
|
|
292 | =item lnk $port1, $port2 |
|
|
293 | |
|
|
294 | Link two ports. This is simply a shorthand for: |
|
|
295 | |
|
|
296 | mon $port1, $port2; |
|
|
297 | mon $port2, $port1; |
|
|
298 | |
|
|
299 | It means that if either one is killed abnormally, the other one gets |
|
|
300 | killed as well. |
|
|
301 | |
|
|
302 | =item $local_port = port |
|
|
303 | |
|
|
304 | Create a new local port object that supports message matching. |
|
|
305 | |
|
|
306 | =item $portid = port { my @msg = @_; $finished } |
|
|
307 | |
|
|
308 | Creates a "mini port", that is, a very lightweight port without any |
|
|
309 | pattern matching behind it, and returns its ID. |
|
|
310 | |
|
|
311 | The block will be called for every message received on the port. When the |
|
|
312 | callback returns a true value its job is considered "done" and the port |
|
|
313 | will be destroyed. Otherwise it will stay alive. |
|
|
314 | |
|
|
315 | The message will be passed as-is, no extra argument (i.e. no port id) will |
|
|
316 | be passed to the callback. |
|
|
317 | |
|
|
318 | If you need the local port id in the callback, this works nicely: |
|
|
319 | |
|
|
320 | my $port; $port = miniport { |
|
|
321 | snd $otherport, reply => $port; |
|
|
322 | }; |
|
|
323 | |
|
|
324 | =cut |
|
|
325 | |
331 | |
326 | sub port(;&) { |
332 | sub port(;&) { |
327 | my $id = "$UNIQ." . $ID++; |
333 | my $id = "$UNIQ." . $ID++; |
328 | my $port = "$NODE#$id"; |
334 | my $port = "$NODE#$id"; |
329 | |
335 | |
330 | if (@_) { |
336 | rcv $port, shift || \&_kilme; |
331 | my $cb = shift; |
|
|
332 | $PORT{$id} = sub { |
|
|
333 | local $SELF = $port; |
|
|
334 | eval { |
|
|
335 | &$cb |
|
|
336 | and kil $id; |
|
|
337 | }; |
|
|
338 | _self_die if $@; |
|
|
339 | }; |
|
|
340 | } else { |
|
|
341 | my $self = bless { |
|
|
342 | id => "$NODE#$id", |
|
|
343 | }, "AnyEvent::MP::Port"; |
|
|
344 | |
|
|
345 | $PORT_DATA{$id} = $self; |
|
|
346 | $PORT{$id} = sub { |
|
|
347 | local $SELF = $port; |
|
|
348 | |
|
|
349 | eval { |
|
|
350 | for (@{ $self->{rc0}{$_[0]} }) { |
|
|
351 | $_ && &{$_->[0]} |
|
|
352 | && undef $_; |
|
|
353 | } |
|
|
354 | |
|
|
355 | for (@{ $self->{rcv}{$_[0]} }) { |
|
|
356 | $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1] |
|
|
357 | && &{$_->[0]} |
|
|
358 | && undef $_; |
|
|
359 | } |
|
|
360 | |
|
|
361 | for (@{ $self->{any} }) { |
|
|
362 | $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1] |
|
|
363 | && &{$_->[0]} |
|
|
364 | && undef $_; |
|
|
365 | } |
|
|
366 | }; |
|
|
367 | _self_die if $@; |
|
|
368 | }; |
|
|
369 | } |
|
|
370 | |
337 | |
371 | $port |
338 | $port |
372 | } |
339 | } |
373 | |
340 | |
374 | =item reg $portid, $name |
341 | =item rcv $local_port, $callback->(@msg) |
375 | |
342 | |
376 | Registers the given port under the name C<$name>. If the name already |
343 | Replaces the default callback on the specified port. There is no way to |
377 | exists it is replaced. |
344 | remove the default callback: use C<sub { }> to disable it, or better |
|
|
345 | C<kil> the port when it is no longer needed. |
378 | |
346 | |
379 | A port can only be registered under one well known name. |
|
|
380 | |
|
|
381 | A port automatically becomes unregistered when it is killed. |
|
|
382 | |
|
|
383 | =cut |
|
|
384 | |
|
|
385 | sub reg(@) { |
|
|
386 | my ($portid, $name) = @_; |
|
|
387 | |
|
|
388 | $REG{$name} = $portid; |
|
|
389 | } |
|
|
390 | |
|
|
391 | =item rcv $portid, tagstring => $callback->(@msg), ... |
|
|
392 | |
|
|
393 | =item rcv $portid, $smartmatch => $callback->(@msg), ... |
|
|
394 | |
|
|
395 | =item rcv $portid, [$smartmatch...] => $callback->(@msg), ... |
|
|
396 | |
|
|
397 | Register callbacks to be called on matching messages on the given port. |
|
|
398 | |
|
|
399 | The callback has to return a true value when its work is done, after |
|
|
400 | which is will be removed, or a false value in which case it will stay |
|
|
401 | registered. |
|
|
402 | |
|
|
403 | The global C<$SELF> (exported by this module) contains C<$portid> while |
347 | The global C<$SELF> (exported by this module) contains C<$port> while |
404 | executing the callback. |
348 | executing the callback. Runtime errors during callback execution will |
|
|
349 | result in the port being C<kil>ed. |
405 | |
350 | |
406 | Runtime errors wdurign callback execution will result in the port being |
351 | The default callback received all messages not matched by a more specific |
407 | C<kil>ed. |
352 | C<tag> match. |
408 | |
353 | |
409 | If the match is an array reference, then it will be matched against the |
354 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
410 | first elements of the message, otherwise only the first element is being |
|
|
411 | matched. |
|
|
412 | |
355 | |
413 | Any element in the match that is specified as C<_any_> (a function |
356 | Register callbacks to be called on messages starting with the given tag on |
414 | exported by this module) matches any single element of the message. |
357 | the given port (and return the port), or unregister it (when C<$callback> |
|
|
358 | is C<$undef>). |
415 | |
359 | |
416 | While not required, it is highly recommended that the first matching |
360 | The original message will be passed to the callback, after the first |
417 | element is a string identifying the message. The one-string-only match is |
361 | element (the tag) has been removed. The callback will use the same |
418 | also the most efficient match (by far). |
362 | environment as the default callback (see above). |
|
|
363 | |
|
|
364 | Example: create a port and bind receivers on it in one go. |
|
|
365 | |
|
|
366 | my $port = rcv port, |
|
|
367 | msg1 => sub { ... }, |
|
|
368 | msg2 => sub { ... }, |
|
|
369 | ; |
|
|
370 | |
|
|
371 | Example: create a port, bind receivers and send it in a message elsewhere |
|
|
372 | in one go: |
|
|
373 | |
|
|
374 | snd $otherport, reply => |
|
|
375 | rcv port, |
|
|
376 | msg1 => sub { ... }, |
|
|
377 | ... |
|
|
378 | ; |
419 | |
379 | |
420 | =cut |
380 | =cut |
421 | |
381 | |
422 | sub rcv($@) { |
382 | sub rcv($@) { |
|
|
383 | my $port = shift; |
423 | my ($noderef, $port) = split /#/, shift, 2; |
384 | my ($noderef, $portid) = split /#/, $port, 2; |
424 | |
385 | |
425 | ($NODE{$noderef} || add_node $noderef) == $NODE{""} |
386 | ($NODE{$noderef} || add_node $noderef) == $NODE{""} |
426 | or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught"; |
387 | or Carp::croak "$port: rcv can only be called on local ports, caught"; |
427 | |
|
|
428 | my $self = $PORT_DATA{$port} |
|
|
429 | or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught"; |
|
|
430 | |
|
|
431 | "AnyEvent::MP::Port" eq ref $self |
|
|
432 | or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught"; |
|
|
433 | |
388 | |
434 | while (@_) { |
389 | while (@_) { |
435 | my ($match, $cb) = splice @_, 0, 2; |
|
|
436 | |
|
|
437 | if (!ref $match) { |
390 | if (ref $_[0]) { |
438 | push @{ $self->{rc0}{$match} }, [$cb]; |
391 | if (my $self = $PORT_DATA{$portid}) { |
439 | } elsif (("ARRAY" eq ref $match && !ref $match->[0])) { |
392 | "AnyEvent::MP::Port" eq ref $self |
440 | my ($type, @match) = @$match; |
393 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
441 | @match |
394 | |
442 | ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match] |
395 | $self->[2] = shift; |
443 | : push @{ $self->{rc0}{$match->[0]} }, [$cb]; |
|
|
444 | } else { |
396 | } else { |
445 | push @{ $self->{any} }, [$cb, $match]; |
397 | my $cb = shift; |
|
|
398 | $PORT{$portid} = sub { |
|
|
399 | local $SELF = $port; |
|
|
400 | eval { &$cb }; _self_die if $@; |
|
|
401 | }; |
|
|
402 | } |
|
|
403 | } elsif (defined $_[0]) { |
|
|
404 | my $self = $PORT_DATA{$portid} ||= do { |
|
|
405 | my $self = bless [$PORT{$port} || sub { }, { }, $port], "AnyEvent::MP::Port"; |
|
|
406 | |
|
|
407 | $PORT{$portid} = sub { |
|
|
408 | local $SELF = $port; |
|
|
409 | |
|
|
410 | if (my $cb = $self->[1]{$_[0]}) { |
|
|
411 | shift; |
|
|
412 | eval { &$cb }; _self_die if $@; |
|
|
413 | } else { |
|
|
414 | &{ $self->[0] }; |
|
|
415 | } |
|
|
416 | }; |
|
|
417 | |
|
|
418 | $self |
|
|
419 | }; |
|
|
420 | |
|
|
421 | "AnyEvent::MP::Port" eq ref $self |
|
|
422 | or Carp::croak "$port: rcv can only be called on message matching ports, caught"; |
|
|
423 | |
|
|
424 | my ($tag, $cb) = splice @_, 0, 2; |
|
|
425 | |
|
|
426 | if (defined $cb) { |
|
|
427 | $self->[1]{$tag} = $cb; |
|
|
428 | } else { |
|
|
429 | delete $self->[1]{$tag}; |
|
|
430 | } |
446 | } |
431 | } |
447 | } |
432 | } |
|
|
433 | |
|
|
434 | $port |
448 | } |
435 | } |
449 | |
436 | |
450 | =item $closure = psub { BLOCK } |
437 | =item $closure = psub { BLOCK } |
451 | |
438 | |
452 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
439 | Remembers C<$SELF> and creates a closure out of the BLOCK. When the |
… | |
… | |
483 | $res |
470 | $res |
484 | } |
471 | } |
485 | } |
472 | } |
486 | } |
473 | } |
487 | |
474 | |
488 | =back |
475 | =item $guard = mon $port, $cb->(@reason) |
489 | |
476 | |
490 | =head1 FUNCTIONS FOR NODES |
477 | =item $guard = mon $port, $rcvport |
491 | |
478 | |
492 | =over 4 |
479 | =item $guard = mon $port |
493 | |
480 | |
494 | =item become_public $noderef |
481 | =item $guard = mon $port, $rcvport, @msg |
495 | |
482 | |
496 | Tells the node to become a public node, i.e. reachable from other nodes. |
483 | Monitor the given port and do something when the port is killed or |
|
|
484 | messages to it were lost, and optionally return a guard that can be used |
|
|
485 | to stop monitoring again. |
497 | |
486 | |
498 | The first argument is the (unresolved) node reference of the local node |
487 | C<mon> effectively guarantees that, in the absence of hardware failures, |
499 | (if missing then the empty string is used). |
488 | that after starting the monitor, either all messages sent to the port |
|
|
489 | will arrive, or the monitoring action will be invoked after possible |
|
|
490 | message loss has been detected. No messages will be lost "in between" |
|
|
491 | (after the first lost message no further messages will be received by the |
|
|
492 | port). After the monitoring action was invoked, further messages might get |
|
|
493 | delivered again. |
500 | |
494 | |
501 | It is quite common to not specify anything, in which case the local node |
495 | In the first form (callback), the callback is simply called with any |
502 | tries to listen on the default port, or to only specify a port number, in |
496 | number of C<@reason> elements (no @reason means that the port was deleted |
503 | which case AnyEvent::MP tries to guess the local addresses. |
497 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
|
|
498 | C<eval> if unsure. |
504 | |
499 | |
|
|
500 | In the second form (another port given), the other port (C<$rcvport>) |
|
|
501 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
|
|
502 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
503 | port is killed with the same reason. |
|
|
504 | |
|
|
505 | The third form (kill self) is the same as the second form, except that |
|
|
506 | C<$rvport> defaults to C<$SELF>. |
|
|
507 | |
|
|
508 | In the last form (message), a message of the form C<@msg, @reason> will be |
|
|
509 | C<snd>. |
|
|
510 | |
|
|
511 | As a rule of thumb, monitoring requests should always monitor a port from |
|
|
512 | a local port (or callback). The reason is that kill messages might get |
|
|
513 | lost, just like any other message. Another less obvious reason is that |
|
|
514 | even monitoring requests can get lost (for exmaple, when the connection |
|
|
515 | to the other node goes down permanently). When monitoring a port locally |
|
|
516 | these problems do not exist. |
|
|
517 | |
|
|
518 | Example: call a given callback when C<$port> is killed. |
|
|
519 | |
|
|
520 | mon $port, sub { warn "port died because of <@_>\n" }; |
|
|
521 | |
|
|
522 | Example: kill ourselves when C<$port> is killed abnormally. |
|
|
523 | |
|
|
524 | mon $port; |
|
|
525 | |
|
|
526 | Example: send us a restart message when another C<$port> is killed. |
|
|
527 | |
|
|
528 | mon $port, $self => "restart"; |
|
|
529 | |
505 | =cut |
530 | =cut |
|
|
531 | |
|
|
532 | sub mon { |
|
|
533 | my ($noderef, $port) = split /#/, shift, 2; |
|
|
534 | |
|
|
535 | my $node = $NODE{$noderef} || add_node $noderef; |
|
|
536 | |
|
|
537 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
|
|
538 | |
|
|
539 | unless (ref $cb) { |
|
|
540 | if (@_) { |
|
|
541 | # send a kill info message |
|
|
542 | my (@msg) = ($cb, @_); |
|
|
543 | $cb = sub { snd @msg, @_ }; |
|
|
544 | } else { |
|
|
545 | # simply kill other port |
|
|
546 | my $port = $cb; |
|
|
547 | $cb = sub { kil $port, @_ if @_ }; |
|
|
548 | } |
|
|
549 | } |
|
|
550 | |
|
|
551 | $node->monitor ($port, $cb); |
|
|
552 | |
|
|
553 | defined wantarray |
|
|
554 | and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) } |
|
|
555 | } |
|
|
556 | |
|
|
557 | =item $guard = mon_guard $port, $ref, $ref... |
|
|
558 | |
|
|
559 | Monitors the given C<$port> and keeps the passed references. When the port |
|
|
560 | is killed, the references will be freed. |
|
|
561 | |
|
|
562 | Optionally returns a guard that will stop the monitoring. |
|
|
563 | |
|
|
564 | This function is useful when you create e.g. timers or other watchers and |
|
|
565 | want to free them when the port gets killed: |
|
|
566 | |
|
|
567 | $port->rcv (start => sub { |
|
|
568 | my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub { |
|
|
569 | undef $timer if 0.9 < rand; |
|
|
570 | }); |
|
|
571 | }); |
|
|
572 | |
|
|
573 | =cut |
|
|
574 | |
|
|
575 | sub mon_guard { |
|
|
576 | my ($port, @refs) = @_; |
|
|
577 | |
|
|
578 | #TODO: mon-less form? |
|
|
579 | |
|
|
580 | mon $port, sub { 0 && @refs } |
|
|
581 | } |
|
|
582 | |
|
|
583 | =item kil $port[, @reason] |
|
|
584 | |
|
|
585 | Kill the specified port with the given C<@reason>. |
|
|
586 | |
|
|
587 | If no C<@reason> is specified, then the port is killed "normally" (linked |
|
|
588 | ports will not be kileld, or even notified). |
|
|
589 | |
|
|
590 | Otherwise, linked ports get killed with the same reason (second form of |
|
|
591 | C<mon>, see below). |
|
|
592 | |
|
|
593 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
|
|
594 | will be reported as reason C<< die => $@ >>. |
|
|
595 | |
|
|
596 | Transport/communication errors are reported as C<< transport_error => |
|
|
597 | $message >>. |
|
|
598 | |
|
|
599 | =cut |
|
|
600 | |
|
|
601 | =item $port = spawn $node, $initfunc[, @initdata] |
|
|
602 | |
|
|
603 | Creates a port on the node C<$node> (which can also be a port ID, in which |
|
|
604 | case it's the node where that port resides). |
|
|
605 | |
|
|
606 | The port ID of the newly created port is return immediately, and it is |
|
|
607 | permissible to immediately start sending messages or monitor the port. |
|
|
608 | |
|
|
609 | After the port has been created, the init function is |
|
|
610 | called. This function must be a fully-qualified function name |
|
|
611 | (e.g. C<MyApp::Chat::Server::init>). To specify a function in the main |
|
|
612 | program, use C<::name>. |
|
|
613 | |
|
|
614 | If the function doesn't exist, then the node tries to C<require> |
|
|
615 | the package, then the package above the package and so on (e.g. |
|
|
616 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
|
|
617 | exists or it runs out of package names. |
|
|
618 | |
|
|
619 | The init function is then called with the newly-created port as context |
|
|
620 | object (C<$SELF>) and the C<@initdata> values as arguments. |
|
|
621 | |
|
|
622 | A common idiom is to pass your own port, monitor the spawned port, and |
|
|
623 | in the init function, monitor the original port. This two-way monitoring |
|
|
624 | ensures that both ports get cleaned up when there is a problem. |
|
|
625 | |
|
|
626 | Example: spawn a chat server port on C<$othernode>. |
|
|
627 | |
|
|
628 | # this node, executed from within a port context: |
|
|
629 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
|
|
630 | mon $server; |
|
|
631 | |
|
|
632 | # init function on C<$othernode> |
|
|
633 | sub connect { |
|
|
634 | my ($srcport) = @_; |
|
|
635 | |
|
|
636 | mon $srcport; |
|
|
637 | |
|
|
638 | rcv $SELF, sub { |
|
|
639 | ... |
|
|
640 | }; |
|
|
641 | } |
|
|
642 | |
|
|
643 | =cut |
|
|
644 | |
|
|
645 | sub _spawn { |
|
|
646 | my $port = shift; |
|
|
647 | my $init = shift; |
|
|
648 | |
|
|
649 | local $SELF = "$NODE#$port"; |
|
|
650 | eval { |
|
|
651 | &{ load_func $init } |
|
|
652 | }; |
|
|
653 | _self_die if $@; |
|
|
654 | } |
|
|
655 | |
|
|
656 | sub spawn(@) { |
|
|
657 | my ($noderef, undef) = split /#/, shift, 2; |
|
|
658 | |
|
|
659 | my $id = "$RUNIQ." . $ID++; |
|
|
660 | |
|
|
661 | $_[0] =~ /::/ |
|
|
662 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
|
|
663 | |
|
|
664 | ($NODE{$noderef} || add_node $noderef) |
|
|
665 | ->send (["", "AnyEvent::MP::_spawn" => $id, @_]); |
|
|
666 | |
|
|
667 | "$noderef#$id" |
|
|
668 | } |
506 | |
669 | |
507 | =back |
670 | =back |
508 | |
671 | |
509 | =head1 NODE MESSAGES |
672 | =head1 NODE MESSAGES |
510 | |
673 | |
… | |
… | |
552 | |
715 | |
553 | =back |
716 | =back |
554 | |
717 | |
555 | =head1 AnyEvent::MP vs. Distributed Erlang |
718 | =head1 AnyEvent::MP vs. Distributed Erlang |
556 | |
719 | |
557 | AnyEvent::MP got lots of its ideas from distributed erlang (erlang node |
720 | AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node |
558 | == aemp node, erlang process == aemp port), so many of the documents and |
721 | == aemp node, Erlang process == aemp port), so many of the documents and |
559 | programming techniques employed by erlang apply to AnyEvent::MP. Here is a |
722 | programming techniques employed by Erlang apply to AnyEvent::MP. Here is a |
560 | sample: |
723 | sample: |
561 | |
724 | |
562 | http://www.erlang.se/doc/programming_rules.shtml |
725 | http://www.Erlang.se/doc/programming_rules.shtml |
563 | http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
726 | http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4 |
564 | http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6 |
727 | http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6 |
565 | http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
728 | http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5 |
566 | |
729 | |
567 | Despite the similarities, there are also some important differences: |
730 | Despite the similarities, there are also some important differences: |
568 | |
731 | |
569 | =over 4 |
732 | =over 4 |
570 | |
733 | |
… | |
… | |
575 | convenience functionality. |
738 | convenience functionality. |
576 | |
739 | |
577 | This means that AEMP requires a less tightly controlled environment at the |
740 | This means that AEMP requires a less tightly controlled environment at the |
578 | cost of longer node references and a slightly higher management overhead. |
741 | cost of longer node references and a slightly higher management overhead. |
579 | |
742 | |
|
|
743 | =item Erlang has a "remote ports are like local ports" philosophy, AEMP |
|
|
744 | uses "local ports are like remote ports". |
|
|
745 | |
|
|
746 | The failure modes for local ports are quite different (runtime errors |
|
|
747 | only) then for remote ports - when a local port dies, you I<know> it dies, |
|
|
748 | when a connection to another node dies, you know nothing about the other |
|
|
749 | port. |
|
|
750 | |
|
|
751 | Erlang pretends remote ports are as reliable as local ports, even when |
|
|
752 | they are not. |
|
|
753 | |
|
|
754 | AEMP encourages a "treat remote ports differently" philosophy, with local |
|
|
755 | ports being the special case/exception, where transport errors cannot |
|
|
756 | occur. |
|
|
757 | |
580 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
758 | =item * Erlang uses processes and a mailbox, AEMP does not queue. |
581 | |
759 | |
582 | Erlang uses processes that selctively receive messages, and therefore |
760 | Erlang uses processes that selectively receive messages, and therefore |
583 | needs a queue. AEMP is event based, queuing messages would serve no useful |
761 | needs a queue. AEMP is event based, queuing messages would serve no |
584 | purpose. |
762 | useful purpose. For the same reason the pattern-matching abilities of |
|
|
763 | AnyEvent::MP are more limited, as there is little need to be able to |
|
|
764 | filter messages without dequeing them. |
585 | |
765 | |
586 | (But see L<Coro::MP> for a more erlang-like process model on top of AEMP). |
766 | (But see L<Coro::MP> for a more Erlang-like process model on top of AEMP). |
587 | |
767 | |
588 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
768 | =item * Erlang sends are synchronous, AEMP sends are asynchronous. |
589 | |
769 | |
590 | Sending messages in erlang is synchronous and blocks the process. AEMP |
770 | Sending messages in Erlang is synchronous and blocks the process (and |
591 | sends are immediate, connection establishment is handled in the |
771 | so does not need a queue that can overflow). AEMP sends are immediate, |
592 | background. |
772 | connection establishment is handled in the background. |
593 | |
773 | |
594 | =item * Erlang can silently lose messages, AEMP cannot. |
774 | =item * Erlang suffers from silent message loss, AEMP does not. |
595 | |
775 | |
596 | Erlang makes few guarantees on messages delivery - messages can get lost |
776 | Erlang makes few guarantees on messages delivery - messages can get lost |
597 | without any of the processes realising it (i.e. you send messages a, b, |
777 | without any of the processes realising it (i.e. you send messages a, b, |
598 | and c, and the other side only receives messages a and c). |
778 | and c, and the other side only receives messages a and c). |
599 | |
779 | |
600 | AEMP guarantees correct ordering, and the guarantee that there are no |
780 | AEMP guarantees correct ordering, and the guarantee that there are no |
601 | holes in the message sequence. |
781 | holes in the message sequence. |
602 | |
782 | |
603 | =item * In erlang, processes can be declared dead and later be found to be |
783 | =item * In Erlang, processes can be declared dead and later be found to be |
604 | alive. |
784 | alive. |
605 | |
785 | |
606 | In erlang it can happen that a monitored process is declared dead and |
786 | In Erlang it can happen that a monitored process is declared dead and |
607 | linked processes get killed, but later it turns out that the process is |
787 | linked processes get killed, but later it turns out that the process is |
608 | still alive - and can receive messages. |
788 | still alive - and can receive messages. |
609 | |
789 | |
610 | In AEMP, when port monitoring detects a port as dead, then that port will |
790 | In AEMP, when port monitoring detects a port as dead, then that port will |
611 | eventually be killed - it cannot happen that a node detects a port as dead |
791 | eventually be killed - it cannot happen that a node detects a port as dead |
612 | and then later sends messages to it, finding it is still alive. |
792 | and then later sends messages to it, finding it is still alive. |
613 | |
793 | |
614 | =item * Erlang can send messages to the wrong port, AEMP does not. |
794 | =item * Erlang can send messages to the wrong port, AEMP does not. |
615 | |
795 | |
616 | In erlang it is quite possible that a node that restarts reuses a process |
796 | In Erlang it is quite likely that a node that restarts reuses a process ID |
617 | ID known to other nodes for a completely different process, causing |
797 | known to other nodes for a completely different process, causing messages |
618 | messages destined for that process to end up in an unrelated process. |
798 | destined for that process to end up in an unrelated process. |
619 | |
799 | |
620 | AEMP never reuses port IDs, so old messages or old port IDs floating |
800 | AEMP never reuses port IDs, so old messages or old port IDs floating |
621 | around in the network will not be sent to an unrelated port. |
801 | around in the network will not be sent to an unrelated port. |
622 | |
802 | |
623 | =item * Erlang uses unprotected connections, AEMP uses secure |
803 | =item * Erlang uses unprotected connections, AEMP uses secure |
… | |
… | |
627 | securely authenticate nodes. |
807 | securely authenticate nodes. |
628 | |
808 | |
629 | =item * The AEMP protocol is optimised for both text-based and binary |
809 | =item * The AEMP protocol is optimised for both text-based and binary |
630 | communications. |
810 | communications. |
631 | |
811 | |
632 | The AEMP protocol, unlike the erlang protocol, supports both |
812 | The AEMP protocol, unlike the Erlang protocol, supports both |
633 | language-independent text-only protocols (good for debugging) and binary, |
813 | language-independent text-only protocols (good for debugging) and binary, |
634 | language-specific serialisers (e.g. Storable). |
814 | language-specific serialisers (e.g. Storable). |
635 | |
815 | |
636 | It has also been carefully designed to be implementable in other languages |
816 | It has also been carefully designed to be implementable in other languages |
637 | with a minimum of work while gracefully degrading fucntionality to make the |
817 | with a minimum of work while gracefully degrading fucntionality to make the |
638 | protocol simple. |
818 | protocol simple. |
639 | |
819 | |
|
|
820 | =item * AEMP has more flexible monitoring options than Erlang. |
|
|
821 | |
|
|
822 | In Erlang, you can chose to receive I<all> exit signals as messages |
|
|
823 | or I<none>, there is no in-between, so monitoring single processes is |
|
|
824 | difficult to implement. Monitoring in AEMP is more flexible than in |
|
|
825 | Erlang, as one can choose between automatic kill, exit message or callback |
|
|
826 | on a per-process basis. |
|
|
827 | |
|
|
828 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
|
|
829 | |
|
|
830 | Monitoring in Erlang is not an indicator of process death/crashes, |
|
|
831 | as linking is (except linking is unreliable in Erlang). |
|
|
832 | |
|
|
833 | In AEMP, you don't "look up" registered port names or send to named ports |
|
|
834 | that might or might not be persistent. Instead, you normally spawn a port |
|
|
835 | on the remote node. The init function monitors the you, and you monitor |
|
|
836 | the remote port. Since both monitors are local to the node, they are much |
|
|
837 | more reliable. |
|
|
838 | |
|
|
839 | This also saves round-trips and avoids sending messages to the wrong port |
|
|
840 | (hard to do in Erlang). |
|
|
841 | |
|
|
842 | =back |
|
|
843 | |
|
|
844 | =head1 RATIONALE |
|
|
845 | |
|
|
846 | =over 4 |
|
|
847 | |
|
|
848 | =item Why strings for ports and noderefs, why not objects? |
|
|
849 | |
|
|
850 | We considered "objects", but found that the actual number of methods |
|
|
851 | thatc an be called are very low. Since port IDs and noderefs travel over |
|
|
852 | the network frequently, the serialising/deserialising would add lots of |
|
|
853 | overhead, as well as having to keep a proxy object. |
|
|
854 | |
|
|
855 | Strings can easily be printed, easily serialised etc. and need no special |
|
|
856 | procedures to be "valid". |
|
|
857 | |
|
|
858 | And a a miniport consists of a single closure stored in a global hash - it |
|
|
859 | can't become much cheaper. |
|
|
860 | |
|
|
861 | =item Why favour JSON, why not real serialising format such as Storable? |
|
|
862 | |
|
|
863 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
|
|
864 | format, but currently there is no way to make a node use Storable by |
|
|
865 | default. |
|
|
866 | |
|
|
867 | The default framing protocol is JSON because a) JSON::XS is many times |
|
|
868 | faster for small messages and b) most importantly, after years of |
|
|
869 | experience we found that object serialisation is causing more problems |
|
|
870 | than it gains: Just like function calls, objects simply do not travel |
|
|
871 | easily over the network, mostly because they will always be a copy, so you |
|
|
872 | always have to re-think your design. |
|
|
873 | |
|
|
874 | Keeping your messages simple, concentrating on data structures rather than |
|
|
875 | objects, will keep your messages clean, tidy and efficient. |
|
|
876 | |
640 | =back |
877 | =back |
641 | |
878 | |
642 | =head1 SEE ALSO |
879 | =head1 SEE ALSO |
643 | |
880 | |
644 | L<AnyEvent>. |
881 | L<AnyEvent>. |