1 | NAME |
1 | NAME |
2 | AnyEvent - the DBI of event loop programming |
2 | AnyEvent - the DBI of event loop programming |
3 | |
3 | |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, |
4 | EV, Event, Glib, Tk, UV, Perl, Event::Lib, Irssi, rxvt-unicode, |
5 | Qt, FLTK and POE are various supported event loops/environments. |
5 | IO::Async, Qt, FLTK and POE are various supported event |
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6 | loops/environments. |
6 | |
7 | |
7 | SYNOPSIS |
8 | SYNOPSIS |
8 | use AnyEvent; |
9 | use AnyEvent; |
9 | |
10 | |
10 | # if you prefer function calls, look at the AE manpage for |
11 | # if you prefer function calls, look at the AE manpage for |
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262 | |
263 | |
263 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
264 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
264 | |
265 | |
265 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
266 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
266 | warn "timeout\n"; |
267 | warn "timeout\n"; |
267 | }; |
268 | }); |
268 | |
269 | |
269 | TIMING ISSUES |
270 | TIMING ISSUES |
270 | There are two ways to handle timers: based on real time (relative, "fire |
271 | 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 |
272 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
272 | o'clock"). |
273 | o'clock"). |
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403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
404 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
404 | pure perl implementation). |
405 | pure perl implementation). |
405 | |
406 | |
406 | Safe/Unsafe Signals |
407 | Safe/Unsafe Signals |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
408 | Perl signals can be either "safe" (synchronous to opcode handling) or |
408 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
409 | "unsafe" (asynchronous) - the former might delay signal delivery |
409 | latter might corrupt your memory. |
410 | indefinitely, the latter might corrupt your memory. |
410 | |
411 | |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
412 | AnyEvent signal handlers are, in addition, synchronous to the event |
412 | loop, i.e. they will not interrupt your running perl program but will |
413 | 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, |
414 | only be called as part of the normal event handling (just like timer, |
414 | I/O etc. callbacks, too). |
415 | I/O etc. callbacks, too). |
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416 | Signal Races, Delays and Workarounds |
417 | Signal Races, Delays and Workarounds |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
418 | 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 |
419 | 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. |
420 | 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 |
421 | 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 |
422 | will be delayed. The maximum time a signal might be delayed is 10 |
422 | in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable |
423 | seconds by default, but can be overriden via |
423 | can be changed only before the first signal watcher is created, and |
424 | $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY |
424 | should be left alone otherwise. This variable determines how often |
425 | - see the "ENVIRONMENT VARIABLES" section for details. |
425 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
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426 | will cause fewer spurious wake-ups, which is better for power and CPU |
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427 | saving. |
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428 | |
426 | |
429 | All these problems can be avoided by installing the optional |
427 | All these problems can be avoided by installing the optional |
430 | Async::Interrupt module, which works with most event loops. It will not |
428 | 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 |
429 | 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 |
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433 | latency). For those, you just have to suffer the delays. |
430 | not with POE currently). For those, you just have to suffer the delays. |
434 | |
431 | |
435 | CHILD PROCESS WATCHERS |
432 | CHILD PROCESS WATCHERS |
436 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
433 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
437 | |
434 | |
438 | You can also watch for a child process exit and catch its exit status. |
435 | You can also watch for a child process exit and catch its exit status. |
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473 | |
470 | |
474 | Example: fork a process and wait for it |
471 | Example: fork a process and wait for it |
475 | |
472 | |
476 | my $done = AnyEvent->condvar; |
473 | my $done = AnyEvent->condvar; |
477 | |
474 | |
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475 | # this forks and immediately calls exit in the child. this |
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476 | # normally has all sorts of bad consequences for your parent, |
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477 | # so take this as an example only. always fork and exec, |
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478 | # or call POSIX::_exit, in real code. |
478 | my $pid = fork or exit 5; |
479 | my $pid = fork or exit 5; |
479 | |
480 | |
480 | my $w = AnyEvent->child ( |
481 | my $w = AnyEvent->child ( |
481 | pid => $pid, |
482 | pid => $pid, |
482 | cb => sub { |
483 | cb => sub { |
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722 | This works because for every event source (EOF on file handle), |
723 | 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 |
724 | there is one call to "begin", so the condvar waits for all calls to |
724 | "end" before sending. |
725 | "end" before sending. |
725 | |
726 | |
726 | The ping example mentioned above is slightly more complicated, as |
727 | The ping example mentioned above is slightly more complicated, as |
727 | the there are results to be passwd back, and the number of tasks |
728 | the there are results to be passed back, and the number of tasks |
728 | that are begun can potentially be zero: |
729 | that are begun can potentially be zero: |
729 | |
730 | |
730 | my $cv = AnyEvent->condvar; |
731 | my $cv = AnyEvent->condvar; |
731 | |
732 | |
732 | my %result; |
733 | my %result; |
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740 | }; |
741 | }; |
741 | } |
742 | } |
742 | |
743 | |
743 | $cv->end; |
744 | $cv->end; |
744 | |
745 | |
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746 | ... |
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747 | |
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748 | my $results = $cv->recv; |
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749 | |
745 | This code fragment supposedly pings a number of hosts and calls |
750 | This code fragment supposedly pings a number of hosts and calls |
746 | "send" after results for all then have have been gathered - in any |
751 | "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 |
752 | 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 |
753 | 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 |
754 | result for it. Since "begin" and "end" only maintain a counter, the |
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778 | In list context, all parameters passed to "send" will be returned, |
783 | In list context, all parameters passed to "send" will be returned, |
779 | in scalar context only the first one will be returned. |
784 | in scalar context only the first one will be returned. |
780 | |
785 | |
781 | Note that doing a blocking wait in a callback is not supported by |
786 | 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" |
787 | 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 |
788 | is not allowed and the "recv" call will "croak" if such a condition |
784 | is detected. This condition can be slightly loosened by using |
789 | is detected. This requirement can be dropped by relying on |
785 | Coro::AnyEvent, which allows you to do a blocking "->recv" from any |
790 | Coro::AnyEvent , which allows you to do a blocking "->recv" from any |
786 | thread that doesn't run the event loop itself. |
791 | thread that doesn't run the event loop itself. Coro::AnyEvent is |
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792 | loaded automatically when Coro is used with AnyEvent, so code does |
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793 | not need to do anything special to take advantage of that: any code |
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794 | that would normally block your program because it calls "recv", be |
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795 | executed in an "async" thread instead without blocking other |
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796 | threads. |
787 | |
797 | |
788 | Not all event models support a blocking wait - some die in that case |
798 | 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 |
799 | (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, |
800 | using this from a module, never require a blocking wait*. Instead, |
791 | let the caller decide whether the call will block or not (for |
801 | let the caller decide whether the call will block or not (for |
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834 | by the main program. |
844 | by the main program. |
835 | |
845 | |
836 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
846 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
837 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
847 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
838 | AnyEvent::Impl::Tk based on Tk, very broken. |
848 | AnyEvent::Impl::Tk based on Tk, very broken. |
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849 | AnyEvent::Impl::UV based on UV, innovated square wheels. |
839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
850 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
851 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
852 | AnyEvent::Impl::Irssi used when running within irssi. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
853 | AnyEvent::Impl::IOAsync based on IO::Async. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
854 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
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975 | To understand the usefulness of this function, consider a function |
986 | To understand the usefulness of this function, consider a function |
976 | that asynchronously does something for you and returns some |
987 | that asynchronously does something for you and returns some |
977 | transaction object or guard to let you cancel the operation. For |
988 | transaction object or guard to let you cancel the operation. For |
978 | example, "AnyEvent::Socket::tcp_connect": |
989 | example, "AnyEvent::Socket::tcp_connect": |
979 | |
990 | |
980 | # start a conenction attempt unless one is active |
991 | # start a connection attempt unless one is active |
981 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
992 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
982 | delete $self->{connect_guard}; |
993 | delete $self->{connect_guard}; |
983 | ... |
994 | ... |
984 | }; |
995 | }; |
985 | |
996 | |
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1010 | If AnyEvent::Log is not loaded then this function makes a simple |
1021 | If AnyEvent::Log is not loaded then this function makes a simple |
1011 | test to see whether the message will be logged. If the test succeeds |
1022 | test to see whether the message will be logged. If the test succeeds |
1012 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1023 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1013 | consequently, look at the AnyEvent::Log documentation for details. |
1024 | consequently, look at the AnyEvent::Log documentation for details. |
1014 | |
1025 | |
1015 | If the test fails it will simply return. |
1026 | If the test fails it will simply return. Right now this happens when |
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1027 | a numerical loglevel is used and it is larger than the level |
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1028 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
1016 | |
1029 | |
1017 | If you want to sprinkle loads of logging calls around your code, |
1030 | If you want to sprinkle loads of logging calls around your code, |
1018 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1031 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1019 | function, which can reduce typing, codesize and can reduce the |
1032 | function, which can reduce typing, codesize and can reduce the |
1020 | logging overhead enourmously. |
1033 | logging overhead enourmously. |
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1034 | |
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1035 | AnyEvent::fh_block $filehandle |
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1036 | AnyEvent::fh_unblock $filehandle |
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1037 | Sets blocking or non-blocking behaviour for the given filehandle. |
1021 | |
1038 | |
1022 | WHAT TO DO IN A MODULE |
1039 | WHAT TO DO IN A MODULE |
1023 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1040 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1024 | freely, but you should not load a specific event module or rely on it. |
1041 | freely, but you should not load a specific event module or rely on it. |
1025 | |
1042 | |
… | |
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1084 | modules come as part of AnyEvent, the others are available via CPAN (see |
1101 | modules come as part of AnyEvent, the others are available via CPAN (see |
1085 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
1102 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
1086 | non-exhaustive list), and the list is heavily biased towards modules of |
1103 | non-exhaustive list), and the list is heavily biased towards modules of |
1087 | the AnyEvent author himself :) |
1104 | the AnyEvent author himself :) |
1088 | |
1105 | |
1089 | AnyEvent::Util |
1106 | AnyEvent::Util (part of the AnyEvent distribution) |
1090 | Contains various utility functions that replace often-used blocking |
1107 | Contains various utility functions that replace often-used blocking |
1091 | functions such as "inet_aton" with event/callback-based versions. |
1108 | functions such as "inet_aton" with event/callback-based versions. |
1092 | |
1109 | |
1093 | AnyEvent::Socket |
1110 | AnyEvent::Socket (part of the AnyEvent distribution) |
1094 | Provides various utility functions for (internet protocol) sockets, |
1111 | Provides various utility functions for (internet protocol) sockets, |
1095 | addresses and name resolution. Also functions to create non-blocking |
1112 | addresses and name resolution. Also functions to create non-blocking |
1096 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1113 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1097 | more. |
1114 | more. |
1098 | |
1115 | |
1099 | AnyEvent::Handle |
1116 | AnyEvent::Handle (part of the AnyEvent distribution) |
1100 | Provide read and write buffers, manages watchers for reads and |
1117 | Provide read and write buffers, manages watchers for reads and |
1101 | writes, supports raw and formatted I/O, I/O queued and fully |
1118 | writes, supports raw and formatted I/O, I/O queued and fully |
1102 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1119 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1103 | |
1120 | |
1104 | AnyEvent::DNS |
1121 | AnyEvent::DNS (part of the AnyEvent distribution) |
1105 | Provides rich asynchronous DNS resolver capabilities. |
1122 | Provides rich asynchronous DNS resolver capabilities. |
1106 | |
1123 | |
1107 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1124 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1108 | AnyEvent::IGS, AnyEvent::FCP |
1125 | AnyEvent::IGS, AnyEvent::FCP |
1109 | Implement event-based interfaces to the protocols of the same name |
1126 | Implement event-based interfaces to the protocols of the same name |
1110 | (for the curious, IGS is the International Go Server and FCP is the |
1127 | (for the curious, IGS is the International Go Server and FCP is the |
1111 | Freenet Client Protocol). |
1128 | Freenet Client Protocol). |
1112 | |
1129 | |
1113 | AnyEvent::AIO |
1130 | AnyEvent::AIO (part of the AnyEvent distribution) |
1114 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1131 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1115 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1132 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1116 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1133 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1117 | event-based file I/O, and much more. |
1134 | event-based file I/O, and much more. |
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1135 | |
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1136 | AnyEvent::Fork, AnyEvent::Fork::RPC, AnyEvent::Fork::Pool, |
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1137 | AnyEvent::Fork::Remote |
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1138 | These let you safely fork new subprocesses, either locally or |
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1139 | remotely (e.g.v ia ssh), using some RPC protocol or not, without the |
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1140 | limitations normally imposed by fork (AnyEvent works fine for |
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1141 | example). Dynamically-resized worker pools are obviously included as |
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1142 | well. |
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1143 | |
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1144 | And they are quite tiny and fast as well - "abusing" AnyEvent::Fork |
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1145 | just to exec external programs can easily beat using "fork" and |
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1146 | "exec" (or even "system") in most programs. |
1118 | |
1147 | |
1119 | AnyEvent::Filesys::Notify |
1148 | AnyEvent::Filesys::Notify |
1120 | AnyEvent is good for non-blocking stuff, but it can't detect file or |
1149 | AnyEvent is good for non-blocking stuff, but it can't detect file or |
1121 | path changes (e.g. "watch this directory for new files", "watch this |
1150 | path changes (e.g. "watch this directory for new files", "watch this |
1122 | file for changes"). The AnyEvent::Filesys::Notify module promises to |
1151 | file for changes"). The AnyEvent::Filesys::Notify module promises to |
… | |
… | |
1124 | and some weird, without doubt broken, stuff on OS X to monitor |
1153 | and some weird, without doubt broken, stuff on OS X to monitor |
1125 | files. It can fall back to blocking scans at regular intervals |
1154 | files. It can fall back to blocking scans at regular intervals |
1126 | transparently on other platforms, so it's about as portable as it |
1155 | transparently on other platforms, so it's about as portable as it |
1127 | gets. |
1156 | gets. |
1128 | |
1157 | |
1129 | (I haven't used it myself, but I haven't heard anybody complaining |
1158 | (I haven't used it myself, but it seems the biggest problem with it |
1130 | about it yet). |
1159 | is it quite bad performance). |
1131 | |
1160 | |
1132 | AnyEvent::DBI |
1161 | AnyEvent::DBI |
1133 | Executes DBI requests asynchronously in a proxy process for you, |
1162 | Executes DBI requests asynchronously in a proxy process for you, |
1134 | notifying you in an event-based way when the operation is finished. |
1163 | notifying you in an event-based way when the operation is finished. |
1135 | |
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1136 | AnyEvent::HTTPD |
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1137 | A simple embedded webserver. |
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1138 | |
1164 | |
1139 | AnyEvent::FastPing |
1165 | AnyEvent::FastPing |
1140 | The fastest ping in the west. |
1166 | The fastest ping in the west. |
1141 | |
1167 | |
1142 | Coro |
1168 | Coro |
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1216 | This ensures that child processes will not see the "AE_" variables. |
1242 | This ensures that child processes will not see the "AE_" variables. |
1217 | |
1243 | |
1218 | The following environment variables are currently known to AnyEvent: |
1244 | The following environment variables are currently known to AnyEvent: |
1219 | |
1245 | |
1220 | "PERL_ANYEVENT_VERBOSE" |
1246 | "PERL_ANYEVENT_VERBOSE" |
1221 | By default, AnyEvent will be completely silent except in fatal |
1247 | By default, AnyEvent will log messages with loglevel 4 ("error") or |
1222 | conditions. You can set this environment variable to make AnyEvent |
1248 | higher (see AnyEvent::Log). You can set this environment variable to |
1223 | more talkative. If you want to do more than just set the global |
1249 | a numerical loglevel to make AnyEvent more (or less) talkative. |
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1250 | |
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1251 | If you want to do more than just set the global logging level you |
1224 | logging level you should have a look at "PERL_ANYEVENT_LOG", which |
1252 | should have a look at "PERL_ANYEVENT_LOG", which allows much more |
1225 | allows much more complex specifications. |
1253 | complex specifications. |
1226 | |
1254 | |
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1255 | When set to 0 ("off"), then no messages whatsoever will be logged |
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1256 | with everything else at defaults. |
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1257 | |
1227 | When set to 5 or higher (warn), causes AnyEvent to warn about |
1258 | When set to 5 or higher ("warn"), AnyEvent warns about unexpected |
1228 | unexpected conditions, such as not being able to load the event |
1259 | conditions, such as not being able to load the event model specified |
1229 | model specified by "PERL_ANYEVENT_MODEL", or a guard callback |
1260 | by "PERL_ANYEVENT_MODEL", or a guard callback throwing an exception |
1230 | throwing an exception - this is the minimum recommended level. |
1261 | - this is the minimum recommended level for use during development. |
1231 | |
1262 | |
1232 | When set to 7 or higher (info), cause AnyEvent to report which event |
1263 | When set to 7 or higher (info), AnyEvent reports which event model |
1233 | model it chooses. |
1264 | it chooses. |
1234 | |
1265 | |
1235 | When set to 8 or higher (debug), then AnyEvent will report extra |
1266 | When set to 8 or higher (debug), then AnyEvent will report extra |
1236 | information on which optional modules it loads and how it implements |
1267 | information on which optional modules it loads and how it implements |
1237 | certain features. |
1268 | certain features. |
1238 | |
1269 | |
… | |
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1250 | itself. |
1281 | itself. |
1251 | |
1282 | |
1252 | Note that specifying this environment variable causes the |
1283 | Note that specifying this environment variable causes the |
1253 | AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" |
1284 | AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" |
1254 | does not, so only using the latter saves a few hundred kB of memory |
1285 | does not, so only using the latter saves a few hundred kB of memory |
1255 | until the first message is being logged. |
1286 | unless a module explicitly needs the extra features of |
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1287 | AnyEvent::Log. |
1256 | |
1288 | |
1257 | "PERL_ANYEVENT_STRICT" |
1289 | "PERL_ANYEVENT_STRICT" |
1258 | AnyEvent does not do much argument checking by default, as thorough |
1290 | AnyEvent does not do much argument checking by default, as thorough |
1259 | argument checking is very costly. Setting this variable to a true |
1291 | argument checking is very costly. Setting this variable to a true |
1260 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1292 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
… | |
… | |
1267 | is definitely recommended to keep it off in production. Keeping |
1299 | is definitely recommended to keep it off in production. Keeping |
1268 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1300 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1269 | programs can be very useful, however. |
1301 | programs can be very useful, however. |
1270 | |
1302 | |
1271 | "PERL_ANYEVENT_DEBUG_SHELL" |
1303 | "PERL_ANYEVENT_DEBUG_SHELL" |
1272 | If this env variable is set, then its contents will be interpreted |
1304 | If this env variable is nonempty, then its contents will be |
1273 | by "AnyEvent::Socket::parse_hostport" (after replacing every |
1305 | interpreted by "AnyEvent::Socket::parse_hostport" and |
1274 | occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" |
1306 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
1275 | is bound on that port. The shell object is saved in |
1307 | the process pid). The shell object is saved in |
1276 | $AnyEvent::Debug::SHELL. |
1308 | $AnyEvent::Debug::SHELL. |
1277 | |
1309 | |
1278 | This happens when the first watcher is created. |
1310 | This happens when the first watcher is created. |
1279 | |
1311 | |
1280 | For example, to bind a debug shell on a unix domain socket in |
1312 | For example, to bind a debug shell on a unix domain socket in |
1281 | /tmp/debug<pid>.sock, you could use this: |
1313 | /tmp/debug<pid>.sock, you could use this: |
1282 | |
1314 | |
1283 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
1315 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1316 | # connect with e.g.: socat readline /tmp/debug123.sock |
1284 | |
1317 | |
|
|
1318 | Or to bind to tcp port 4545 on localhost: |
|
|
1319 | |
|
|
1320 | PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog |
|
|
1321 | # connect with e.g.: telnet localhost 4545 |
|
|
1322 | |
1285 | Note that creating sockets in /tmp is very unsafe on multiuser |
1323 | Note that creating sockets in /tmp or on localhost is very unsafe on |
1286 | systems. |
1324 | multiuser systems. |
1287 | |
1325 | |
1288 | "PERL_ANYEVENT_DEBUG_WRAP" |
1326 | "PERL_ANYEVENT_DEBUG_WRAP" |
1289 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1327 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1290 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1328 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1291 | |
1329 | |
… | |
… | |
1307 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1345 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1308 | could start your program like this: |
1346 | could start your program like this: |
1309 | |
1347 | |
1310 | PERL_ANYEVENT_MODEL=Perl perl ... |
1348 | PERL_ANYEVENT_MODEL=Perl perl ... |
1311 | |
1349 | |
|
|
1350 | "PERL_ANYEVENT_IO_MODEL" |
|
|
1351 | The current file I/O model - see AnyEvent::IO for more info. |
|
|
1352 | |
|
|
1353 | At the moment, only "Perl" (small, pure-perl, synchronous) and |
|
|
1354 | "IOAIO" (truly asynchronous) are supported. The default is "IOAIO" |
|
|
1355 | if AnyEvent::AIO can be loaded, otherwise it is "Perl". |
|
|
1356 | |
1312 | "PERL_ANYEVENT_PROTOCOLS" |
1357 | "PERL_ANYEVENT_PROTOCOLS" |
1313 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1358 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1314 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1359 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1315 | change, or be the result of auto probing). |
1360 | change, or be the result of auto probing). |
1316 | |
1361 | |
… | |
… | |
1319 | mentioned will be used, and preference will be given to protocols |
1364 | mentioned will be used, and preference will be given to protocols |
1320 | mentioned earlier in the list. |
1365 | mentioned earlier in the list. |
1321 | |
1366 | |
1322 | This variable can effectively be used for denial-of-service attacks |
1367 | This variable can effectively be used for denial-of-service attacks |
1323 | against local programs (e.g. when setuid), although the impact is |
1368 | against local programs (e.g. when setuid), although the impact is |
1324 | likely small, as the program has to handle conenction and other |
1369 | likely small, as the program has to handle connection and other |
1325 | failures anyways. |
1370 | failures anyways. |
1326 | |
1371 | |
1327 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1372 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1328 | IPv6, but support both and try to use both. |
1373 | IPv6, but support both and try to use both. |
1329 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1374 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
… | |
… | |
1351 | |
1396 | |
1352 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1397 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1353 | The default value for the "max_outstanding" parameter for the |
1398 | The default value for the "max_outstanding" parameter for the |
1354 | default DNS resolver - this is the maximum number of parallel DNS |
1399 | default DNS resolver - this is the maximum number of parallel DNS |
1355 | requests that are sent to the DNS server. |
1400 | requests that are sent to the DNS server. |
|
|
1401 | |
|
|
1402 | "PERL_ANYEVENT_MAX_SIGNAL_LATENCY" |
|
|
1403 | Perl has inherently racy signal handling (you can basically choose |
|
|
1404 | between losing signals and memory corruption) - pure perl event |
|
|
1405 | loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't |
|
|
1406 | available) therefore have to poll regularly to avoid losing signals. |
|
|
1407 | |
|
|
1408 | Some event loops are racy, but don't poll regularly, and some event |
|
|
1409 | loops are written in C but are still racy. For those event loops, |
|
|
1410 | AnyEvent installs a timer that regularly wakes up the event loop. |
|
|
1411 | |
|
|
1412 | By default, the interval for this timer is 10 seconds, but you can |
|
|
1413 | override this delay with this environment variable (or by setting |
|
|
1414 | the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal |
|
|
1415 | watchers). |
|
|
1416 | |
|
|
1417 | Lower values increase CPU (and energy) usage, higher values can |
|
|
1418 | introduce long delays when reaping children or waiting for signals. |
|
|
1419 | |
|
|
1420 | The AnyEvent::Async module, if available, will be used to avoid this |
|
|
1421 | polling (with most event loops). |
1356 | |
1422 | |
1357 | "PERL_ANYEVENT_RESOLV_CONF" |
1423 | "PERL_ANYEVENT_RESOLV_CONF" |
1358 | The absolute path to a resolv.conf-style file to use instead of |
1424 | The absolute path to a resolv.conf-style file to use instead of |
1359 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1425 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1360 | resolver, or the empty string to select the default configuration. |
1426 | resolver, or the empty string to select the default configuration. |
… | |
… | |
1963 | This module is part of perl since release 5.008. It will be used |
2029 | This module is part of perl since release 5.008. It will be used |
1964 | when the chosen event library does not come with a timing source of |
2030 | when the chosen event library does not come with a timing source of |
1965 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
2031 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1966 | load it to try to use a monotonic clock for timing stability. |
2032 | load it to try to use a monotonic clock for timing stability. |
1967 | |
2033 | |
|
|
2034 | AnyEvent::AIO (and IO::AIO) |
|
|
2035 | The default implementation of AnyEvent::IO is to do I/O |
|
|
2036 | synchronously, stopping programs while they access the disk, which |
|
|
2037 | is fine for a lot of programs. |
|
|
2038 | |
|
|
2039 | Installing AnyEvent::AIO (and its IO::AIO dependency) makes it |
|
|
2040 | switch to a true asynchronous implementation, so event processing |
|
|
2041 | can continue even while waiting for disk I/O. |
|
|
2042 | |
1968 | FORK |
2043 | FORK |
1969 | Most event libraries are not fork-safe. The ones who are usually are |
2044 | Most event libraries are not fork-safe. The ones who are usually are |
1970 | because they rely on inefficient but fork-safe "select" or "poll" calls |
2045 | because they rely on inefficient but fork-safe "select" or "poll" calls |
1971 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
2046 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
1972 | epoll are usually badly thought-out hacks that are incompatible with |
2047 | epoll are usually badly thought-out hacks that are incompatible with |
… | |
… | |
1979 | usually happens when the first AnyEvent watcher is created, or the |
2054 | usually happens when the first AnyEvent watcher is created, or the |
1980 | library is loaded). |
2055 | library is loaded). |
1981 | |
2056 | |
1982 | If you have to fork, you must either do so *before* creating your first |
2057 | If you have to fork, you must either do so *before* creating your first |
1983 | watcher OR you must not use AnyEvent at all in the child OR you must do |
2058 | watcher OR you must not use AnyEvent at all in the child OR you must do |
1984 | something completely out of the scope of AnyEvent. |
2059 | something completely out of the scope of AnyEvent (see below). |
1985 | |
2060 | |
1986 | The problem of doing event processing in the parent *and* the child is |
2061 | The problem of doing event processing in the parent *and* the child is |
1987 | much more complicated: even for backends that *are* fork-aware or |
2062 | much more complicated: even for backends that *are* fork-aware or |
1988 | fork-safe, their behaviour is not usually what you want: fork clones all |
2063 | fork-safe, their behaviour is not usually what you want: fork clones all |
1989 | watchers, that means all timers, I/O watchers etc. are active in both |
2064 | watchers, that means all timers, I/O watchers etc. are active in both |
1990 | parent and child, which is almost never what you want. USing "exec" to |
2065 | parent and child, which is almost never what you want. Using "exec" to |
1991 | start worker children from some kind of manage rprocess is usually |
2066 | start worker children from some kind of manage prrocess is usually |
1992 | preferred, because it is much easier and cleaner, at the expense of |
2067 | preferred, because it is much easier and cleaner, at the expense of |
1993 | having to have another binary. |
2068 | having to have another binary. |
|
|
2069 | |
|
|
2070 | In addition to logical problems with fork, there are also implementation |
|
|
2071 | problems. For example, on POSIX systems, you cannot fork at all in Perl |
|
|
2072 | code if a thread (I am talking of pthreads here) was ever created in the |
|
|
2073 | process, and this is just the tip of the iceberg. In general, using fork |
|
|
2074 | from Perl is difficult, and attempting to use fork without an exec to |
|
|
2075 | implement some kind of parallel processing is almost certainly doomed. |
|
|
2076 | |
|
|
2077 | To safely fork and exec, you should use a module such as Proc::FastSpawn |
|
|
2078 | that let's you safely fork and exec new processes. |
|
|
2079 | |
|
|
2080 | If you want to do multiprocessing using processes, you can look at the |
|
|
2081 | AnyEvent::Fork module (and some related modules such as |
|
|
2082 | AnyEvent::Fork::RPC, AnyEvent::Fork::Pool and AnyEvent::Fork::Remote). |
|
|
2083 | This module allows you to safely create subprocesses without any |
|
|
2084 | limitations - you can use X11 toolkits or AnyEvent in the children |
|
|
2085 | created by AnyEvent::Fork safely and without any special precautions. |
1994 | |
2086 | |
1995 | SECURITY CONSIDERATIONS |
2087 | SECURITY CONSIDERATIONS |
1996 | AnyEvent can be forced to load any event model via |
2088 | AnyEvent can be forced to load any event model via |
1997 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
2089 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1998 | to execute arbitrary code or directly gain access, it can easily be used |
2090 | to execute arbitrary code or directly gain access, it can easily be used |
… | |
… | |
2033 | |
2125 | |
2034 | Development/Debugging: AnyEvent::Strict (stricter checking), |
2126 | Development/Debugging: AnyEvent::Strict (stricter checking), |
2035 | AnyEvent::Debug (interactive shell, watcher tracing). |
2127 | AnyEvent::Debug (interactive shell, watcher tracing). |
2036 | |
2128 | |
2037 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
2129 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
2038 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK. |
2130 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK, Cocoa::EventLoop, UV. |
2039 | |
2131 | |
2040 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
2132 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
2041 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
2133 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
2042 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
2134 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
2043 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. |
2135 | AnyEvent::Impl::IOAsync, AnyEvent::Impl::Irssi, AnyEvent::Impl::FLTK, |
|
|
2136 | AnyEvent::Impl::Cocoa, AnyEvent::Impl::UV. |
2044 | |
2137 | |
2045 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
2138 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
2046 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2139 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2047 | |
2140 | |
|
|
2141 | Asynchronous File I/O: AnyEvent::IO. |
|
|
2142 | |
2048 | Asynchronous DNS: AnyEvent::DNS. |
2143 | Asynchronous DNS: AnyEvent::DNS. |
2049 | |
2144 | |
2050 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2145 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2051 | |
2146 | |
2052 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
2147 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
2053 | AnyEvent::HTTP. |
2148 | AnyEvent::HTTP. |
2054 | |
2149 | |
2055 | AUTHOR |
2150 | AUTHOR |
2056 | Marc Lehmann <schmorp@schmorp.de> |
2151 | Marc Lehmann <schmorp@schmorp.de> |
2057 | http://home.schmorp.de/ |
2152 | http://anyevent.schmorp.de |
2058 | |
2153 | |