… | |
… | |
57 | as those use one of the supported event loops. It is trivial to add new |
57 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
58 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
59 | |
60 | In addition to being free of having to use I<the one and only true event |
60 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
62 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
65 | technically possible. |
66 | |
66 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
… | |
… | |
108 | |
108 | |
109 | =head1 WATCHERS |
109 | =head1 WATCHERS |
110 | |
110 | |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
112 | stores relevant data for each kind of event you are waiting for, such as |
112 | stores relevant data for each kind of event you are waiting for, such as |
113 | the callback to call, the filehandle to watch, etc. |
113 | the callback to call, the file handle to watch, etc. |
114 | |
114 | |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
116 | creating a watcher it will immediately "watch" for events and invoke the |
116 | creating a watcher it will immediately "watch" for events and invoke the |
117 | callback when the event occurs (of course, only when the event model |
117 | callback when the event occurs (of course, only when the event model |
118 | is in control). |
118 | is in control). |
… | |
… | |
631 | |
631 | |
632 | =item L<AnyEvent::Handle> |
632 | =item L<AnyEvent::Handle> |
633 | |
633 | |
634 | Provide read and write buffers and manages watchers for reads and writes. |
634 | Provide read and write buffers and manages watchers for reads and writes. |
635 | |
635 | |
|
|
636 | =item L<AnyEvent::Socket> |
|
|
637 | |
|
|
638 | Provides various utility functions for (internet protocol) sockets, |
|
|
639 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
640 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
641 | |
636 | =item L<AnyEvent::HTTPD> |
642 | =item L<AnyEvent::HTTPD> |
637 | |
643 | |
638 | Provides a simple web application server framework. |
644 | Provides a simple web application server framework. |
639 | |
645 | |
640 | =item L<AnyEvent::DNS> |
646 | =item L<AnyEvent::DNS> |
641 | |
647 | |
642 | Provides asynchronous DNS resolver capabilities, beyond what |
648 | Provides rich asynchronous DNS resolver capabilities. |
643 | L<AnyEvent::Util> offers. |
|
|
644 | |
649 | |
645 | =item L<AnyEvent::FastPing> |
650 | =item L<AnyEvent::FastPing> |
646 | |
651 | |
647 | The fastest ping in the west. |
652 | The fastest ping in the west. |
648 | |
653 | |
… | |
… | |
700 | our @ISA; |
705 | our @ISA; |
701 | |
706 | |
702 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
707 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
703 | |
708 | |
704 | our @REGISTRY; |
709 | our @REGISTRY; |
|
|
710 | |
|
|
711 | our %PROTOCOL; # (ipv4|ipv6) => (1|2) |
|
|
712 | |
|
|
713 | { |
|
|
714 | my $idx; |
|
|
715 | $PROTOCOL{$_} = ++$idx |
|
|
716 | for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
717 | } |
705 | |
718 | |
706 | my @models = ( |
719 | my @models = ( |
707 | [EV:: => AnyEvent::Impl::EV::], |
720 | [EV:: => AnyEvent::Impl::EV::], |
708 | [Event:: => AnyEvent::Impl::Event::], |
721 | [Event:: => AnyEvent::Impl::Event::], |
709 | [Tk:: => AnyEvent::Impl::Tk::], |
722 | [Tk:: => AnyEvent::Impl::Tk::], |
… | |
… | |
1016 | model it chooses. |
1029 | model it chooses. |
1017 | |
1030 | |
1018 | =item C<PERL_ANYEVENT_MODEL> |
1031 | =item C<PERL_ANYEVENT_MODEL> |
1019 | |
1032 | |
1020 | This can be used to specify the event model to be used by AnyEvent, before |
1033 | This can be used to specify the event model to be used by AnyEvent, before |
1021 | autodetection and -probing kicks in. It must be a string consisting |
1034 | auto detection and -probing kicks in. It must be a string consisting |
1022 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1035 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1023 | and the resulting module name is loaded and if the load was successful, |
1036 | and the resulting module name is loaded and if the load was successful, |
1024 | used as event model. If it fails to load AnyEvent will proceed with |
1037 | used as event model. If it fails to load AnyEvent will proceed with |
1025 | autodetection and -probing. |
1038 | auto detection and -probing. |
1026 | |
1039 | |
1027 | This functionality might change in future versions. |
1040 | This functionality might change in future versions. |
1028 | |
1041 | |
1029 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1042 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1030 | could start your program like this: |
1043 | could start your program like this: |
1031 | |
1044 | |
1032 | PERL_ANYEVENT_MODEL=Perl perl ... |
1045 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1046 | |
|
|
1047 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1048 | |
|
|
1049 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1050 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1051 | of auto probing). |
|
|
1052 | |
|
|
1053 | Must be set to a comma-separated list of protocols or address families, |
|
|
1054 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1055 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1056 | list. |
|
|
1057 | |
|
|
1058 | This variable can effectively be used for denial-of-service attacks |
|
|
1059 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1060 | small, as the program has to handle connection errors already- |
|
|
1061 | |
|
|
1062 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1063 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1064 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1065 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1066 | IPv6, but prefer IPv6 over IPv4. |
|
|
1067 | |
|
|
1068 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1069 | |
|
|
1070 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1071 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1072 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1073 | default. |
|
|
1074 | |
|
|
1075 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1076 | EDNS0 in its DNS requests. |
1033 | |
1077 | |
1034 | =back |
1078 | =back |
1035 | |
1079 | |
1036 | =head1 EXAMPLE PROGRAM |
1080 | =head1 EXAMPLE PROGRAM |
1037 | |
1081 | |
… | |
… | |
1123 | syswrite $txn->{fh}, $txn->{request} |
1167 | syswrite $txn->{fh}, $txn->{request} |
1124 | or die "connection or write error"; |
1168 | or die "connection or write error"; |
1125 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1169 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1126 | |
1170 | |
1127 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1171 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1128 | result and signals any possible waiters that the request ahs finished: |
1172 | result and signals any possible waiters that the request has finished: |
1129 | |
1173 | |
1130 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1174 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1131 | |
1175 | |
1132 | if (end-of-file or data complete) { |
1176 | if (end-of-file or data complete) { |
1133 | $txn->{result} = $txn->{buf}; |
1177 | $txn->{result} = $txn->{buf}; |
… | |
… | |
1141 | |
1185 | |
1142 | $txn->{finished}->recv; |
1186 | $txn->{finished}->recv; |
1143 | return $txn->{result}; |
1187 | return $txn->{result}; |
1144 | |
1188 | |
1145 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1189 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1146 | that occured during request processing. The C<result> method detects |
1190 | that occurred during request processing. The C<result> method detects |
1147 | whether an exception as thrown (it is stored inside the $txn object) |
1191 | whether an exception as thrown (it is stored inside the $txn object) |
1148 | and just throws the exception, which means connection errors and other |
1192 | and just throws the exception, which means connection errors and other |
1149 | problems get reported tot he code that tries to use the result, not in a |
1193 | problems get reported tot he code that tries to use the result, not in a |
1150 | random callback. |
1194 | random callback. |
1151 | |
1195 | |
… | |
… | |
1197 | of various event loops I prepared some benchmarks. |
1241 | of various event loops I prepared some benchmarks. |
1198 | |
1242 | |
1199 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1243 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1200 | |
1244 | |
1201 | Here is a benchmark of various supported event models used natively and |
1245 | Here is a benchmark of various supported event models used natively and |
1202 | through anyevent. The benchmark creates a lot of timers (with a zero |
1246 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
1203 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1247 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1204 | which it is), lets them fire exactly once and destroys them again. |
1248 | which it is), lets them fire exactly once and destroys them again. |
1205 | |
1249 | |
1206 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1250 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1207 | distribution. |
1251 | distribution. |
… | |
… | |
1330 | |
1374 | |
1331 | =back |
1375 | =back |
1332 | |
1376 | |
1333 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1377 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1334 | |
1378 | |
1335 | This benchmark atcually benchmarks the event loop itself. It works by |
1379 | This benchmark actually benchmarks the event loop itself. It works by |
1336 | creating a number of "servers": each server consists of a socketpair, a |
1380 | creating a number of "servers": each server consists of a socket pair, a |
1337 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1381 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1338 | watcher waiting for input on one side of the socket. Each time the socket |
1382 | watcher waiting for input on one side of the socket. Each time the socket |
1339 | watcher reads a byte it will write that byte to a random other "server". |
1383 | watcher reads a byte it will write that byte to a random other "server". |
1340 | |
1384 | |
1341 | The effect is that there will be a lot of I/O watchers, only part of which |
1385 | The effect is that there will be a lot of I/O watchers, only part of which |
1342 | are active at any one point (so there is a constant number of active |
1386 | are active at any one point (so there is a constant number of active |
1343 | fds for each loop iterstaion, but which fds these are is random). The |
1387 | fds for each loop iteration, but which fds these are is random). The |
1344 | timeout is reset each time something is read because that reflects how |
1388 | timeout is reset each time something is read because that reflects how |
1345 | most timeouts work (and puts extra pressure on the event loops). |
1389 | most timeouts work (and puts extra pressure on the event loops). |
1346 | |
1390 | |
1347 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1391 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1348 | (1%) are active. This mirrors the activity of large servers with many |
1392 | (1%) are active. This mirrors the activity of large servers with many |
1349 | connections, most of which are idle at any one point in time. |
1393 | connections, most of which are idle at any one point in time. |
1350 | |
1394 | |
1351 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1395 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1352 | distribution. |
1396 | distribution. |
… | |
… | |
1354 | =head3 Explanation of the columns |
1398 | =head3 Explanation of the columns |
1355 | |
1399 | |
1356 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1400 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1357 | each server has a read and write socket end). |
1401 | each server has a read and write socket end). |
1358 | |
1402 | |
1359 | I<create> is the time it takes to create a socketpair (which is |
1403 | I<create> is the time it takes to create a socket pair (which is |
1360 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1404 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1361 | |
1405 | |
1362 | I<request>, the most important value, is the time it takes to handle a |
1406 | I<request>, the most important value, is the time it takes to handle a |
1363 | single "request", that is, reading the token from the pipe and forwarding |
1407 | single "request", that is, reading the token from the pipe and forwarding |
1364 | it to another server. This includes deleting the old timeout and creating |
1408 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1487 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
1531 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
1488 | |
1532 | |
1489 | |
1533 | |
1490 | =head1 SEE ALSO |
1534 | =head1 SEE ALSO |
1491 | |
1535 | |
|
|
1536 | Utility functions: L<AnyEvent::Util>. |
|
|
1537 | |
1492 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1538 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1493 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1539 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1494 | |
1540 | |
1495 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1541 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1496 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1542 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1497 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1543 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1498 | L<AnyEvent::Impl::POE>. |
1544 | L<AnyEvent::Impl::POE>. |
1499 | |
1545 | |
|
|
1546 | Non-blocking file handles, sockets, TCP clients and |
|
|
1547 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1548 | |
1500 | Asynchronous DNS: L<AnyEvent::DNS>. |
1549 | Asynchronous DNS: L<AnyEvent::DNS>. |
1501 | |
1550 | |
1502 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
1551 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
1503 | |
1552 | |
1504 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1553 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1505 | |
1554 | |
1506 | |
1555 | |
1507 | =head1 AUTHOR |
1556 | =head1 AUTHOR |
1508 | |
1557 | |
1509 | Marc Lehmann <schmorp@schmorp.de> |
1558 | Marc Lehmann <schmorp@schmorp.de> |