… | |
… | |
262 | |
262 | |
263 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
263 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
264 | |
264 | |
265 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
265 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
266 | warn "timeout\n"; |
266 | warn "timeout\n"; |
267 | }; |
267 | }); |
268 | |
268 | |
269 | TIMING ISSUES |
269 | TIMING ISSUES |
270 | There are two ways to handle timers: based on real time (relative, "fire |
270 | There are two ways to handle timers: based on real time (relative, "fire |
271 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
271 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
272 | o'clock"). |
272 | o'clock"). |
… | |
… | |
403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
404 | pure perl implementation). |
404 | pure perl implementation). |
405 | |
405 | |
406 | Safe/Unsafe Signals |
406 | Safe/Unsafe Signals |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
408 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
408 | "unsafe" (asynchronous) - the former might delay signal delivery |
409 | latter might corrupt your memory. |
409 | indefinitely, the latter might corrupt your memory. |
410 | |
410 | |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
412 | loop, i.e. they will not interrupt your running perl program but will |
412 | loop, i.e. they will not interrupt your running perl program but will |
413 | only be called as part of the normal event handling (just like timer, |
413 | only be called as part of the normal event handling (just like timer, |
414 | I/O etc. callbacks, too). |
414 | I/O etc. callbacks, too). |
… | |
… | |
416 | Signal Races, Delays and Workarounds |
416 | Signal Races, Delays and Workarounds |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
419 | race-free signal handling in perl, requiring C libraries for this. |
419 | race-free signal handling in perl, requiring C libraries for this. |
420 | AnyEvent will try to do its best, which means in some cases, signals |
420 | AnyEvent will try to do its best, which means in some cases, signals |
421 | will be delayed. The maximum time a signal might be delayed is specified |
421 | will be delayed. The maximum time a signal might be delayed is 10 |
422 | in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable |
422 | seconds by default, but can be overriden via |
423 | can be changed only before the first signal watcher is created, and |
423 | $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY |
424 | should be left alone otherwise. This variable determines how often |
424 | - see the "ENVIRONMENT VARIABLES" section for details. |
425 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
|
|
426 | will cause fewer spurious wake-ups, which is better for power and CPU |
|
|
427 | saving. |
|
|
428 | |
425 | |
429 | All these problems can be avoided by installing the optional |
426 | All these problems can be avoided by installing the optional |
430 | Async::Interrupt module, which works with most event loops. It will not |
427 | Async::Interrupt module, which works with most event loops. It will not |
431 | work with inherently broken event loops such as Event or Event::Lib (and |
428 | work with inherently broken event loops such as Event or Event::Lib (and |
432 | not with POE currently, as POE does its own workaround with one-second |
|
|
433 | latency). For those, you just have to suffer the delays. |
429 | not with POE currently). For those, you just have to suffer the delays. |
434 | |
430 | |
435 | CHILD PROCESS WATCHERS |
431 | CHILD PROCESS WATCHERS |
436 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
432 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
437 | |
433 | |
438 | You can also watch for a child process exit and catch its exit status. |
434 | You can also watch for a child process exit and catch its exit status. |
… | |
… | |
473 | |
469 | |
474 | Example: fork a process and wait for it |
470 | Example: fork a process and wait for it |
475 | |
471 | |
476 | my $done = AnyEvent->condvar; |
472 | my $done = AnyEvent->condvar; |
477 | |
473 | |
|
|
474 | # this forks and immediately calls exit in the child. this |
|
|
475 | # normally has all sorts of bad consequences for your parent, |
|
|
476 | # so take this as an example only. always fork and exec, |
|
|
477 | # or call POSIX::_exit, in real code. |
478 | my $pid = fork or exit 5; |
478 | my $pid = fork or exit 5; |
479 | |
479 | |
480 | my $w = AnyEvent->child ( |
480 | my $w = AnyEvent->child ( |
481 | pid => $pid, |
481 | pid => $pid, |
482 | cb => sub { |
482 | cb => sub { |
… | |
… | |
722 | This works because for every event source (EOF on file handle), |
722 | This works because for every event source (EOF on file handle), |
723 | there is one call to "begin", so the condvar waits for all calls to |
723 | there is one call to "begin", so the condvar waits for all calls to |
724 | "end" before sending. |
724 | "end" before sending. |
725 | |
725 | |
726 | The ping example mentioned above is slightly more complicated, as |
726 | The ping example mentioned above is slightly more complicated, as |
727 | the there are results to be passwd back, and the number of tasks |
727 | the there are results to be passed back, and the number of tasks |
728 | that are begun can potentially be zero: |
728 | that are begun can potentially be zero: |
729 | |
729 | |
730 | my $cv = AnyEvent->condvar; |
730 | my $cv = AnyEvent->condvar; |
731 | |
731 | |
732 | my %result; |
732 | my %result; |
… | |
… | |
740 | }; |
740 | }; |
741 | } |
741 | } |
742 | |
742 | |
743 | $cv->end; |
743 | $cv->end; |
744 | |
744 | |
|
|
745 | ... |
|
|
746 | |
|
|
747 | my $results = $cv->recv; |
|
|
748 | |
745 | This code fragment supposedly pings a number of hosts and calls |
749 | This code fragment supposedly pings a number of hosts and calls |
746 | "send" after results for all then have have been gathered - in any |
750 | "send" after results for all then have have been gathered - in any |
747 | order. To achieve this, the code issues a call to "begin" when it |
751 | order. To achieve this, the code issues a call to "begin" when it |
748 | starts each ping request and calls "end" when it has received some |
752 | starts each ping request and calls "end" when it has received some |
749 | result for it. Since "begin" and "end" only maintain a counter, the |
753 | result for it. Since "begin" and "end" only maintain a counter, the |
… | |
… | |
778 | In list context, all parameters passed to "send" will be returned, |
782 | In list context, all parameters passed to "send" will be returned, |
779 | in scalar context only the first one will be returned. |
783 | in scalar context only the first one will be returned. |
780 | |
784 | |
781 | Note that doing a blocking wait in a callback is not supported by |
785 | Note that doing a blocking wait in a callback is not supported by |
782 | any event loop, that is, recursive invocation of a blocking "->recv" |
786 | any event loop, that is, recursive invocation of a blocking "->recv" |
783 | is not allowed, and the "recv" call will "croak" if such a condition |
787 | is not allowed and the "recv" call will "croak" if such a condition |
784 | is detected. This condition can be slightly loosened by using |
788 | is detected. This requirement can be dropped by relying on |
785 | Coro::AnyEvent, which allows you to do a blocking "->recv" from any |
789 | Coro::AnyEvent , which allows you to do a blocking "->recv" from any |
786 | thread that doesn't run the event loop itself. |
790 | thread that doesn't run the event loop itself. Coro::AnyEvent is |
|
|
791 | loaded automatically when Coro is used with AnyEvent, so code does |
|
|
792 | not need to do anything special to take advantage of that: any code |
|
|
793 | that would normally block your program because it calls "recv", be |
|
|
794 | executed in an "async" thread instead without blocking other |
|
|
795 | threads. |
787 | |
796 | |
788 | Not all event models support a blocking wait - some die in that case |
797 | Not all event models support a blocking wait - some die in that case |
789 | (programs might want to do that to stay interactive), so *if you are |
798 | (programs might want to do that to stay interactive), so *if you are |
790 | using this from a module, never require a blocking wait*. Instead, |
799 | using this from a module, never require a blocking wait*. Instead, |
791 | let the caller decide whether the call will block or not (for |
800 | let the caller decide whether the call will block or not (for |
… | |
… | |
839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
848 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
849 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
850 | AnyEvent::Impl::Irssi used when running within irssi. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
851 | AnyEvent::Impl::IOAsync based on IO::Async. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
852 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
844 | AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding). |
853 | AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding). |
845 | |
854 | |
846 | Backends with special needs. |
855 | Backends with special needs. |
847 | Qt requires the Qt::Application to be instantiated first, but will |
856 | Qt requires the Qt::Application to be instantiated first, but will |
848 | otherwise be picked up automatically. As long as the main program |
857 | otherwise be picked up automatically. As long as the main program |
849 | instantiates the application before any AnyEvent watchers are |
858 | instantiates the application before any AnyEvent watchers are |
… | |
… | |
1005 | if $some_error_condition; |
1014 | if $some_error_condition; |
1006 | |
1015 | |
1007 | AnyEvent::log $level, $msg[, @args] |
1016 | AnyEvent::log $level, $msg[, @args] |
1008 | Log the given $msg at the given $level. |
1017 | Log the given $msg at the given $level. |
1009 | |
1018 | |
|
|
1019 | If AnyEvent::Log is not loaded then this function makes a simple |
|
|
1020 | test to see whether the message will be logged. If the test succeeds |
1010 | Loads AnyEvent::Log on first use and calls "AnyEvent::Log::log" - |
1021 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1011 | consequently, look at the AnyEvent::Log documentation for details. |
1022 | consequently, look at the AnyEvent::Log documentation for details. |
|
|
1023 | |
|
|
1024 | If the test fails it will simply return. Right now this happens when |
|
|
1025 | a numerical loglevel is used and it is larger than the level |
|
|
1026 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
1012 | |
1027 | |
1013 | If you want to sprinkle loads of logging calls around your code, |
1028 | If you want to sprinkle loads of logging calls around your code, |
1014 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1029 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1015 | function. |
1030 | function, which can reduce typing, codesize and can reduce the |
|
|
1031 | logging overhead enourmously. |
1016 | |
1032 | |
1017 | WHAT TO DO IN A MODULE |
1033 | WHAT TO DO IN A MODULE |
1018 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1034 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1019 | freely, but you should not load a specific event module or rely on it. |
1035 | freely, but you should not load a specific event module or rely on it. |
1020 | |
1036 | |
… | |
… | |
1079 | modules come as part of AnyEvent, the others are available via CPAN (see |
1095 | modules come as part of AnyEvent, the others are available via CPAN (see |
1080 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
1096 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
1081 | non-exhaustive list), and the list is heavily biased towards modules of |
1097 | non-exhaustive list), and the list is heavily biased towards modules of |
1082 | the AnyEvent author himself :) |
1098 | the AnyEvent author himself :) |
1083 | |
1099 | |
1084 | AnyEvent::Util |
1100 | AnyEvent::Util (part of the AnyEvent distribution) |
1085 | Contains various utility functions that replace often-used blocking |
1101 | Contains various utility functions that replace often-used blocking |
1086 | functions such as "inet_aton" with event/callback-based versions. |
1102 | functions such as "inet_aton" with event/callback-based versions. |
1087 | |
1103 | |
1088 | AnyEvent::Socket |
1104 | AnyEvent::Socket (part of the AnyEvent distribution) |
1089 | Provides various utility functions for (internet protocol) sockets, |
1105 | Provides various utility functions for (internet protocol) sockets, |
1090 | addresses and name resolution. Also functions to create non-blocking |
1106 | addresses and name resolution. Also functions to create non-blocking |
1091 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1107 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1092 | more. |
1108 | more. |
1093 | |
1109 | |
1094 | AnyEvent::Handle |
1110 | AnyEvent::Handle (part of the AnyEvent distribution) |
1095 | Provide read and write buffers, manages watchers for reads and |
1111 | Provide read and write buffers, manages watchers for reads and |
1096 | writes, supports raw and formatted I/O, I/O queued and fully |
1112 | writes, supports raw and formatted I/O, I/O queued and fully |
1097 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1113 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1098 | |
1114 | |
1099 | AnyEvent::DNS |
1115 | AnyEvent::DNS (part of the AnyEvent distribution) |
1100 | Provides rich asynchronous DNS resolver capabilities. |
1116 | Provides rich asynchronous DNS resolver capabilities. |
1101 | |
1117 | |
1102 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1118 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1103 | AnyEvent::IGS, AnyEvent::FCP |
1119 | AnyEvent::IGS, AnyEvent::FCP |
1104 | Implement event-based interfaces to the protocols of the same name |
1120 | Implement event-based interfaces to the protocols of the same name |
1105 | (for the curious, IGS is the International Go Server and FCP is the |
1121 | (for the curious, IGS is the International Go Server and FCP is the |
1106 | Freenet Client Protocol). |
1122 | Freenet Client Protocol). |
1107 | |
1123 | |
1108 | AnyEvent::Handle::UDP |
1124 | AnyEvent::AIO (part of the AnyEvent distribution) |
1109 | Here be danger! |
|
|
1110 | |
|
|
1111 | As Pauli would put it, "Not only is it not right, it's not even |
|
|
1112 | wrong!" - there are so many things wrong with AnyEvent::Handle::UDP, |
|
|
1113 | most notably its use of a stream-based API with a protocol that |
|
|
1114 | isn't streamable, that the only way to improve it is to delete it. |
|
|
1115 | |
|
|
1116 | It features data corruption (but typically only under load) and |
|
|
1117 | general confusion. On top, the author is not only clueless about UDP |
|
|
1118 | but also fact-resistant - some gems of his understanding: "connect |
|
|
1119 | doesn't work with UDP", "UDP packets are not IP packets", "UDP only |
|
|
1120 | has datagrams, not packets", "I don't need to implement proper error |
|
|
1121 | checking as UDP doesn't support error checking" and so on - he |
|
|
1122 | doesn't even understand what's wrong with his module when it is |
|
|
1123 | explained to him. |
|
|
1124 | |
|
|
1125 | AnyEvent::DBI |
|
|
1126 | Executes DBI requests asynchronously in a proxy process for you, |
|
|
1127 | notifying you in an event-based way when the operation is finished. |
|
|
1128 | |
|
|
1129 | AnyEvent::AIO |
|
|
1130 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1125 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1131 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1126 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1132 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1127 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1133 | event-based file I/O, and much more. |
1128 | event-based file I/O, and much more. |
1134 | |
1129 | |
|
|
1130 | AnyEvent::Fork, AnyEvent::Fork::RPC, AnyEvent::Fork::Pool, |
|
|
1131 | AnyEvent::Fork::Remote |
|
|
1132 | These let you safely fork new subprocesses, either locally or |
|
|
1133 | remotely (e.g.v ia ssh), using some RPC protocol or not, without the |
|
|
1134 | limitations normally imposed by fork (AnyEvent works fine for |
|
|
1135 | example). Dynamically-resized worker pools are obviously included as |
|
|
1136 | well. |
|
|
1137 | |
|
|
1138 | And they are quite tiny and fast as well - "abusing" AnyEvent::Fork |
|
|
1139 | just to exec external programs can easily beat using "fork" and |
|
|
1140 | "exec" (or even "system") in most programs. |
|
|
1141 | |
|
|
1142 | AnyEvent::Filesys::Notify |
|
|
1143 | AnyEvent is good for non-blocking stuff, but it can't detect file or |
|
|
1144 | path changes (e.g. "watch this directory for new files", "watch this |
|
|
1145 | file for changes"). The AnyEvent::Filesys::Notify module promises to |
|
|
1146 | do just that in a portbale fashion, supporting inotify on GNU/Linux |
|
|
1147 | and some weird, without doubt broken, stuff on OS X to monitor |
|
|
1148 | files. It can fall back to blocking scans at regular intervals |
|
|
1149 | transparently on other platforms, so it's about as portable as it |
|
|
1150 | gets. |
|
|
1151 | |
|
|
1152 | (I haven't used it myself, but it seems the biggest problem with it |
|
|
1153 | is it quite bad performance). |
|
|
1154 | |
1135 | AnyEvent::HTTPD |
1155 | AnyEvent::DBI |
1136 | A simple embedded webserver. |
1156 | Executes DBI requests asynchronously in a proxy process for you, |
|
|
1157 | notifying you in an event-based way when the operation is finished. |
1137 | |
1158 | |
1138 | AnyEvent::FastPing |
1159 | AnyEvent::FastPing |
1139 | The fastest ping in the west. |
1160 | The fastest ping in the west. |
1140 | |
1161 | |
1141 | Coro |
1162 | Coro |
1142 | Has special support for AnyEvent via Coro::AnyEvent. |
1163 | Has special support for AnyEvent via Coro::AnyEvent, which allows |
|
|
1164 | you to simply invert the flow control - don't call us, we will call |
|
|
1165 | you: |
|
|
1166 | |
|
|
1167 | async { |
|
|
1168 | Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it |
|
|
1169 | print "5 seconds later!\n"; |
|
|
1170 | |
|
|
1171 | Coro::AnyEvent::readable *STDIN; # uses an I/O watcher |
|
|
1172 | my $line = <STDIN>; # works for ttys |
|
|
1173 | |
|
|
1174 | AnyEvent::HTTP::http_get "url", Coro::rouse_cb; |
|
|
1175 | my ($body, $hdr) = Coro::rouse_wait; |
|
|
1176 | }; |
1143 | |
1177 | |
1144 | SIMPLIFIED AE API |
1178 | SIMPLIFIED AE API |
1145 | Starting with version 5.0, AnyEvent officially supports a second, much |
1179 | Starting with version 5.0, AnyEvent officially supports a second, much |
1146 | simpler, API that is designed to reduce the calling, typing and memory |
1180 | simpler, API that is designed to reduce the calling, typing and memory |
1147 | overhead by using function call syntax and a fixed number of parameters. |
1181 | overhead by using function call syntax and a fixed number of parameters. |
… | |
… | |
1163 | The pure perl event loop simply re-throws the exception (usually within |
1197 | The pure perl event loop simply re-throws the exception (usually within |
1164 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1198 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1165 | Glib uses "install_exception_handler" and so on. |
1199 | Glib uses "install_exception_handler" and so on. |
1166 | |
1200 | |
1167 | ENVIRONMENT VARIABLES |
1201 | ENVIRONMENT VARIABLES |
1168 | The following environment variables are used by this module or its |
1202 | AnyEvent supports a number of environment variables that tune the |
1169 | submodules. |
1203 | runtime behaviour. They are usually evaluated when AnyEvent is loaded, |
|
|
1204 | initialised, or a submodule that uses them is loaded. Many of them also |
|
|
1205 | cause AnyEvent to load additional modules - for example, |
|
|
1206 | "PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be |
|
|
1207 | loaded. |
1170 | |
1208 | |
1171 | Note that AnyEvent will remove *all* environment variables starting with |
1209 | All the environment variables documented here start with |
1172 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
1210 | "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace. |
1173 | enabled. |
1211 | Other modules are encouraged (but by no means required) to use |
|
|
1212 | "PERL_ANYEVENT_SUBMODULE" if they have registered the |
|
|
1213 | AnyEvent::Submodule namespace on CPAN, for any submodule. For example, |
|
|
1214 | AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it |
|
|
1215 | should not access env variables starting with "AE_", see below). |
|
|
1216 | |
|
|
1217 | All variables can also be set via the "AE_" prefix, that is, instead of |
|
|
1218 | setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case |
|
|
1219 | there is a clash btween anyevent and another program that uses |
|
|
1220 | "AE_something" you can set the corresponding "PERL_ANYEVENT_something" |
|
|
1221 | variable to the empty string, as those variables take precedence. |
|
|
1222 | |
|
|
1223 | When AnyEvent is first loaded, it copies all "AE_xxx" env variables to |
|
|
1224 | their "PERL_ANYEVENT_xxx" counterpart unless that variable already |
|
|
1225 | exists. If taint mode is on, then AnyEvent will remove *all* environment |
|
|
1226 | variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with |
|
|
1227 | "undef" or the empty string, if the corresaponding "AE_" variable is |
|
|
1228 | set). |
|
|
1229 | |
|
|
1230 | The exact algorithm is currently: |
|
|
1231 | |
|
|
1232 | 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV |
|
|
1233 | 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists |
|
|
1234 | 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef. |
|
|
1235 | |
|
|
1236 | This ensures that child processes will not see the "AE_" variables. |
|
|
1237 | |
|
|
1238 | The following environment variables are currently known to AnyEvent: |
1174 | |
1239 | |
1175 | "PERL_ANYEVENT_VERBOSE" |
1240 | "PERL_ANYEVENT_VERBOSE" |
1176 | By default, AnyEvent will be completely silent except in fatal |
1241 | By default, AnyEvent will log messages with loglevel 4 ("error") or |
1177 | conditions. You can set this environment variable to make AnyEvent |
1242 | higher (see AnyEvent::Log). You can set this environment variable to |
1178 | more talkative. |
1243 | a numerical loglevel to make AnyEvent more (or less) talkative. |
1179 | |
1244 | |
|
|
1245 | If you want to do more than just set the global logging level you |
|
|
1246 | should have a look at "PERL_ANYEVENT_LOG", which allows much more |
|
|
1247 | complex specifications. |
|
|
1248 | |
|
|
1249 | When set to 0 ("off"), then no messages whatsoever will be logged |
|
|
1250 | with everything else at defaults. |
|
|
1251 | |
1180 | When set to 5 or higher, causes AnyEvent to warn about unexpected |
1252 | When set to 5 or higher ("warn"), AnyEvent warns about unexpected |
1181 | conditions, such as not being able to load the event model specified |
1253 | conditions, such as not being able to load the event model specified |
1182 | by "PERL_ANYEVENT_MODEL". |
1254 | by "PERL_ANYEVENT_MODEL", or a guard callback throwing an exception |
|
|
1255 | - this is the minimum recommended level for use during development. |
1183 | |
1256 | |
1184 | When set to 7 or higher, cause AnyEvent to report to STDERR which |
1257 | When set to 7 or higher (info), AnyEvent reports which event model |
1185 | event model it chooses. |
1258 | it chooses. |
1186 | |
1259 | |
1187 | When set to 8 or higher, then AnyEvent will report extra information |
1260 | When set to 8 or higher (debug), then AnyEvent will report extra |
1188 | on which optional modules it loads and how it implements certain |
1261 | information on which optional modules it loads and how it implements |
1189 | features. |
1262 | certain features. |
|
|
1263 | |
|
|
1264 | "PERL_ANYEVENT_LOG" |
|
|
1265 | Accepts rather complex logging specifications. For example, you |
|
|
1266 | could log all "debug" messages of some module to stderr, warnings |
|
|
1267 | and above to stderr, and errors and above to syslog, with: |
|
|
1268 | |
|
|
1269 | PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog |
|
|
1270 | |
|
|
1271 | For the rather extensive details, see AnyEvent::Log. |
|
|
1272 | |
|
|
1273 | This variable is evaluated when AnyEvent (or AnyEvent::Log) is |
|
|
1274 | loaded, so will take effect even before AnyEvent has initialised |
|
|
1275 | itself. |
|
|
1276 | |
|
|
1277 | Note that specifying this environment variable causes the |
|
|
1278 | AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" |
|
|
1279 | does not, so only using the latter saves a few hundred kB of memory |
|
|
1280 | unless a module explicitly needs the extra features of |
|
|
1281 | AnyEvent::Log. |
1190 | |
1282 | |
1191 | "PERL_ANYEVENT_STRICT" |
1283 | "PERL_ANYEVENT_STRICT" |
1192 | AnyEvent does not do much argument checking by default, as thorough |
1284 | AnyEvent does not do much argument checking by default, as thorough |
1193 | argument checking is very costly. Setting this variable to a true |
1285 | argument checking is very costly. Setting this variable to a true |
1194 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1286 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
… | |
… | |
1201 | is definitely recommended to keep it off in production. Keeping |
1293 | is definitely recommended to keep it off in production. Keeping |
1202 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1294 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1203 | programs can be very useful, however. |
1295 | programs can be very useful, however. |
1204 | |
1296 | |
1205 | "PERL_ANYEVENT_DEBUG_SHELL" |
1297 | "PERL_ANYEVENT_DEBUG_SHELL" |
1206 | If this env variable is set, then its contents will be interpreted |
1298 | If this env variable is nonempty, then its contents will be |
1207 | by "AnyEvent::Socket::parse_hostport" (after replacing every |
1299 | interpreted by "AnyEvent::Socket::parse_hostport" and |
1208 | occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" |
1300 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
1209 | is bound on that port. The shell object is saved in |
1301 | the process pid). The shell object is saved in |
1210 | $AnyEvent::Debug::SHELL. |
1302 | $AnyEvent::Debug::SHELL. |
1211 | |
1303 | |
1212 | This takes place when the first watcher is created. |
1304 | This happens when the first watcher is created. |
1213 | |
1305 | |
1214 | For example, to bind a debug shell on a unix domain socket in |
1306 | For example, to bind a debug shell on a unix domain socket in |
1215 | /tmp/debug<pid>.sock, you could use this: |
1307 | /tmp/debug<pid>.sock, you could use this: |
1216 | |
1308 | |
1217 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
1309 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1310 | # connect with e.g.: socat readline /tmp/debug123.sock |
1218 | |
1311 | |
|
|
1312 | Or to bind to tcp port 4545 on localhost: |
|
|
1313 | |
|
|
1314 | PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog |
|
|
1315 | # connect with e.g.: telnet localhost 4545 |
|
|
1316 | |
1219 | Note that creating sockets in /tmp is very unsafe on multiuser |
1317 | Note that creating sockets in /tmp or on localhost is very unsafe on |
1220 | systems. |
1318 | multiuser systems. |
1221 | |
1319 | |
1222 | "PERL_ANYEVENT_DEBUG_WRAP" |
1320 | "PERL_ANYEVENT_DEBUG_WRAP" |
1223 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1321 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1224 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1322 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1225 | |
1323 | |
… | |
… | |
1240 | |
1338 | |
1241 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1339 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1242 | could start your program like this: |
1340 | could start your program like this: |
1243 | |
1341 | |
1244 | PERL_ANYEVENT_MODEL=Perl perl ... |
1342 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1343 | |
|
|
1344 | "PERL_ANYEVENT_IO_MODEL" |
|
|
1345 | The current file I/O model - see AnyEvent::IO for more info. |
|
|
1346 | |
|
|
1347 | At the moment, only "Perl" (small, pure-perl, synchronous) and |
|
|
1348 | "IOAIO" (truly asynchronous) are supported. The default is "IOAIO" |
|
|
1349 | if AnyEvent::AIO can be loaded, otherwise it is "Perl". |
1245 | |
1350 | |
1246 | "PERL_ANYEVENT_PROTOCOLS" |
1351 | "PERL_ANYEVENT_PROTOCOLS" |
1247 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1352 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1248 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1353 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1249 | change, or be the result of auto probing). |
1354 | change, or be the result of auto probing). |
… | |
… | |
1263 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1368 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1264 | resolve or contact IPv6 addresses. |
1369 | resolve or contact IPv6 addresses. |
1265 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1370 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1266 | prefer IPv6 over IPv4. |
1371 | prefer IPv6 over IPv4. |
1267 | |
1372 | |
|
|
1373 | "PERL_ANYEVENT_HOSTS" |
|
|
1374 | This variable, if specified, overrides the /etc/hosts file used by |
|
|
1375 | AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be |
|
|
1376 | read from that file instead. |
|
|
1377 | |
1268 | "PERL_ANYEVENT_EDNS0" |
1378 | "PERL_ANYEVENT_EDNS0" |
1269 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1379 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1270 | for DNS. This extension is generally useful to reduce DNS traffic, |
1380 | for DNS. This extension is generally useful to reduce DNS traffic, |
1271 | but some (broken) firewalls drop such DNS packets, which is why it |
1381 | especially when DNSSEC is involved, but some (broken) firewalls drop |
1272 | is off by default. |
1382 | such DNS packets, which is why it is off by default. |
1273 | |
1383 | |
1274 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1384 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1275 | EDNS0 in its DNS requests. |
1385 | EDNS0 in its DNS requests. |
1276 | |
1386 | |
1277 | "PERL_ANYEVENT_MAX_FORKS" |
1387 | "PERL_ANYEVENT_MAX_FORKS" |
… | |
… | |
1281 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1391 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1282 | The default value for the "max_outstanding" parameter for the |
1392 | The default value for the "max_outstanding" parameter for the |
1283 | default DNS resolver - this is the maximum number of parallel DNS |
1393 | default DNS resolver - this is the maximum number of parallel DNS |
1284 | requests that are sent to the DNS server. |
1394 | requests that are sent to the DNS server. |
1285 | |
1395 | |
|
|
1396 | "PERL_ANYEVENT_MAX_SIGNAL_LATENCY" |
|
|
1397 | Perl has inherently racy signal handling (you can basically choose |
|
|
1398 | between losing signals and memory corruption) - pure perl event |
|
|
1399 | loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't |
|
|
1400 | available) therefore have to poll regularly to avoid losing signals. |
|
|
1401 | |
|
|
1402 | Some event loops are racy, but don't poll regularly, and some event |
|
|
1403 | loops are written in C but are still racy. For those event loops, |
|
|
1404 | AnyEvent installs a timer that regularly wakes up the event loop. |
|
|
1405 | |
|
|
1406 | By default, the interval for this timer is 10 seconds, but you can |
|
|
1407 | override this delay with this environment variable (or by setting |
|
|
1408 | the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal |
|
|
1409 | watchers). |
|
|
1410 | |
|
|
1411 | Lower values increase CPU (and energy) usage, higher values can |
|
|
1412 | introduce long delays when reaping children or waiting for signals. |
|
|
1413 | |
|
|
1414 | The AnyEvent::Async module, if available, will be used to avoid this |
|
|
1415 | polling (with most event loops). |
|
|
1416 | |
1286 | "PERL_ANYEVENT_RESOLV_CONF" |
1417 | "PERL_ANYEVENT_RESOLV_CONF" |
1287 | The file to use instead of /etc/resolv.conf (or OS-specific |
1418 | The absolute path to a resolv.conf-style file to use instead of |
1288 | configuration) in the default resolver. When set to the empty |
1419 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1289 | string, no default config will be used. |
1420 | resolver, or the empty string to select the default configuration. |
1290 | |
1421 | |
1291 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1422 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1292 | When neither "ca_file" nor "ca_path" was specified during |
1423 | When neither "ca_file" nor "ca_path" was specified during |
1293 | AnyEvent::TLS context creation, and either of these environment |
1424 | AnyEvent::TLS context creation, and either of these environment |
1294 | variables exist, they will be used to specify CA certificate |
1425 | variables are nonempty, they will be used to specify CA certificate |
1295 | locations instead of a system-dependent default. |
1426 | locations instead of a system-dependent default. |
1296 | |
1427 | |
1297 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1428 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1298 | When these are set to 1, then the respective modules are not loaded. |
1429 | When these are set to 1, then the respective modules are not loaded. |
1299 | Mostly good for testing AnyEvent itself. |
1430 | Mostly good for testing AnyEvent itself. |
… | |
… | |
1892 | This module is part of perl since release 5.008. It will be used |
2023 | This module is part of perl since release 5.008. It will be used |
1893 | when the chosen event library does not come with a timing source of |
2024 | when the chosen event library does not come with a timing source of |
1894 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
2025 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1895 | load it to try to use a monotonic clock for timing stability. |
2026 | load it to try to use a monotonic clock for timing stability. |
1896 | |
2027 | |
|
|
2028 | AnyEvent::AIO (and IO::AIO) |
|
|
2029 | The default implementation of AnyEvent::IO is to do I/O |
|
|
2030 | synchronously, stopping programs while they access the disk, which |
|
|
2031 | is fine for a lot of programs. |
|
|
2032 | |
|
|
2033 | Installing AnyEvent::AIO (and its IO::AIO dependency) makes it |
|
|
2034 | switch to a true asynchronous implementation, so event processing |
|
|
2035 | can continue even while waiting for disk I/O. |
|
|
2036 | |
1897 | FORK |
2037 | FORK |
1898 | Most event libraries are not fork-safe. The ones who are usually are |
2038 | Most event libraries are not fork-safe. The ones who are usually are |
1899 | because they rely on inefficient but fork-safe "select" or "poll" calls |
2039 | because they rely on inefficient but fork-safe "select" or "poll" calls |
1900 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
2040 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
1901 | epoll are usually badly thought-out hacks that are incompatible with |
2041 | epoll are usually badly thought-out hacks that are incompatible with |
… | |
… | |
1908 | usually happens when the first AnyEvent watcher is created, or the |
2048 | usually happens when the first AnyEvent watcher is created, or the |
1909 | library is loaded). |
2049 | library is loaded). |
1910 | |
2050 | |
1911 | If you have to fork, you must either do so *before* creating your first |
2051 | If you have to fork, you must either do so *before* creating your first |
1912 | watcher OR you must not use AnyEvent at all in the child OR you must do |
2052 | watcher OR you must not use AnyEvent at all in the child OR you must do |
1913 | something completely out of the scope of AnyEvent. |
2053 | something completely out of the scope of AnyEvent (see below). |
1914 | |
2054 | |
1915 | The problem of doing event processing in the parent *and* the child is |
2055 | The problem of doing event processing in the parent *and* the child is |
1916 | much more complicated: even for backends that *are* fork-aware or |
2056 | much more complicated: even for backends that *are* fork-aware or |
1917 | fork-safe, their behaviour is not usually what you want: fork clones all |
2057 | fork-safe, their behaviour is not usually what you want: fork clones all |
1918 | watchers, that means all timers, I/O watchers etc. are active in both |
2058 | watchers, that means all timers, I/O watchers etc. are active in both |
1919 | parent and child, which is almost never what you want. USing "exec" to |
2059 | parent and child, which is almost never what you want. Using "exec" to |
1920 | start worker children from some kind of manage rprocess is usually |
2060 | start worker children from some kind of manage prrocess is usually |
1921 | preferred, because it is much easier and cleaner, at the expense of |
2061 | preferred, because it is much easier and cleaner, at the expense of |
1922 | having to have another binary. |
2062 | having to have another binary. |
|
|
2063 | |
|
|
2064 | In addition to logical problems with fork, there are also implementation |
|
|
2065 | problems. For example, on POSIX systems, you cannot fork at all in Perl |
|
|
2066 | code if a thread (I am talking of pthreads here) was ever created in the |
|
|
2067 | process, and this is just the tip of the iceberg. In general, using fork |
|
|
2068 | from Perl is difficult, and attempting to use fork without an exec to |
|
|
2069 | implement some kind of parallel processing is almost certainly doomed. |
|
|
2070 | |
|
|
2071 | To safely fork and exec, you should use a module such as Proc::FastSpawn |
|
|
2072 | that let's you safely fork and exec new processes. |
|
|
2073 | |
|
|
2074 | If you want to do multiprocessing using processes, you can look at the |
|
|
2075 | AnyEvent::Fork module (and some related modules such as |
|
|
2076 | AnyEvent::Fork::RPC, AnyEvent::Fork::Pool and AnyEvent::Fork::Remote). |
|
|
2077 | This module allows you to safely create subprocesses without any |
|
|
2078 | limitations - you can use X11 toolkits or AnyEvent in the children |
|
|
2079 | created by AnyEvent::Fork safely and without any special precautions. |
1923 | |
2080 | |
1924 | SECURITY CONSIDERATIONS |
2081 | SECURITY CONSIDERATIONS |
1925 | AnyEvent can be forced to load any event model via |
2082 | AnyEvent can be forced to load any event model via |
1926 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
2083 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1927 | to execute arbitrary code or directly gain access, it can easily be used |
2084 | to execute arbitrary code or directly gain access, it can easily be used |
… | |
… | |
1972 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. |
2129 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. |
1973 | |
2130 | |
1974 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
2131 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
1975 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2132 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1976 | |
2133 | |
|
|
2134 | Asynchronous File I/O: AnyEvent::IO. |
|
|
2135 | |
1977 | Asynchronous DNS: AnyEvent::DNS. |
2136 | Asynchronous DNS: AnyEvent::DNS. |
1978 | |
2137 | |
1979 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2138 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
1980 | |
2139 | |
1981 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
2140 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
1982 | AnyEvent::HTTP. |
2141 | AnyEvent::HTTP. |
1983 | |
2142 | |
1984 | AUTHOR |
2143 | AUTHOR |
1985 | Marc Lehmann <schmorp@schmorp.de> |
2144 | Marc Lehmann <schmorp@schmorp.de> |
1986 | http://home.schmorp.de/ |
2145 | http://anyevent.schmorp.de |
1987 | |
2146 | |