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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802 | $bool = $cv->ready |
812 | $bool = $cv->ready |
803 | Returns true when the condition is "true", i.e. whether "send" or |
813 | Returns true when the condition is "true", i.e. whether "send" or |
804 | "croak" have been called. |
814 | "croak" have been called. |
805 | |
815 | |
806 | $cb = $cv->cb ($cb->($cv)) |
816 | $cb = $cv->cb ($cb->($cv)) |
807 | This is a mutator function that returns the callback set and |
817 | This is a mutator function that returns the callback set (or "undef" |
808 | optionally replaces it before doing so. |
818 | if not) and optionally replaces it before doing so. |
809 | |
819 | |
810 | The callback will be called when the condition becomes "true", i.e. |
820 | The callback will be called when the condition becomes "true", i.e. |
811 | when "send" or "croak" are called, with the only argument being the |
821 | when "send" or "croak" are called, with the only argument being the |
812 | condition variable itself. If the condition is already true, the |
822 | condition variable itself. If the condition is already true, the |
813 | callback is called immediately when it is set. Calling "recv" inside |
823 | callback is called immediately when it is set. Calling "recv" inside |
814 | the callback or at any later time is guaranteed not to block. |
824 | the callback or at any later time is guaranteed not to block. |
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825 | |
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826 | Additionally, when the callback is invoked, it is also removed from |
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827 | the condvar (reset to "undef"), so the condvar does not keep a |
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828 | reference to the callback after invocation. |
815 | |
829 | |
816 | SUPPORTED EVENT LOOPS/BACKENDS |
830 | SUPPORTED EVENT LOOPS/BACKENDS |
817 | The available backend classes are (every class has its own manpage): |
831 | The available backend classes are (every class has its own manpage): |
818 | |
832 | |
819 | Backends that are autoprobed when no other event loop can be found. |
833 | Backends that are autoprobed when no other event loop can be found. |
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834 | by the main program. |
848 | by the main program. |
835 | |
849 | |
836 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
850 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
837 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
851 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
838 | AnyEvent::Impl::Tk based on Tk, very broken. |
852 | AnyEvent::Impl::Tk based on Tk, very broken. |
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853 | AnyEvent::Impl::UV based on UV, innovated square wheels. |
839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
854 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
855 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
856 | AnyEvent::Impl::Irssi used when running within irssi. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
857 | AnyEvent::Impl::IOAsync based on IO::Async. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
858 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
844 | AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding). |
859 | AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding). |
845 | |
860 | |
846 | Backends with special needs. |
861 | Backends with special needs. |
847 | Qt requires the Qt::Application to be instantiated first, but will |
862 | Qt requires the Qt::Application to be instantiated first, but will |
848 | otherwise be picked up automatically. As long as the main program |
863 | otherwise be picked up automatically. As long as the main program |
849 | instantiates the application before any AnyEvent watchers are |
864 | instantiates the application before any AnyEvent watchers are |
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899 | $guard = AnyEvent::post_detect { BLOCK } |
914 | $guard = AnyEvent::post_detect { BLOCK } |
900 | Arranges for the code block to be executed as soon as the event |
915 | Arranges for the code block to be executed as soon as the event |
901 | model is autodetected (or immediately if that has already happened). |
916 | model is autodetected (or immediately if that has already happened). |
902 | |
917 | |
903 | The block will be executed *after* the actual backend has been |
918 | The block will be executed *after* the actual backend has been |
904 | detected ($AnyEvent::MODEL is set), but *before* any watchers have |
919 | detected ($AnyEvent::MODEL is set), so it is possible to do some |
905 | been created, so it is possible to e.g. patch @AnyEvent::ISA or do |
920 | initialisation only when AnyEvent is actually initialised - see the |
906 | other initialisations - see the sources of AnyEvent::Strict or |
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907 | AnyEvent::AIO to see how this is used. |
921 | sources of AnyEvent::AIO to see how this is used. |
908 | |
922 | |
909 | The most common usage is to create some global watchers, without |
923 | The most common usage is to create some global watchers, without |
910 | forcing event module detection too early, for example, AnyEvent::AIO |
924 | forcing event module detection too early. For example, AnyEvent::AIO |
911 | creates and installs the global IO::AIO watcher in a "post_detect" |
925 | creates and installs the global IO::AIO watcher in a "post_detect" |
912 | block to avoid autodetecting the event module at load time. |
926 | block to avoid autodetecting the event module at load time. |
913 | |
927 | |
914 | If called in scalar or list context, then it creates and returns an |
928 | If called in scalar or list context, then it creates and returns an |
915 | object that automatically removes the callback again when it is |
929 | object that automatically removes the callback again when it is |
… | |
… | |
931 | # able to just C<undef $WATCHER> if the watcher causes them grief. |
945 | # able to just C<undef $WATCHER> if the watcher causes them grief. |
932 | |
946 | |
933 | $WATCHER ||= $guard; |
947 | $WATCHER ||= $guard; |
934 | |
948 | |
935 | @AnyEvent::post_detect |
949 | @AnyEvent::post_detect |
936 | If there are any code references in this array (you can "push" to it |
950 | This is a lower level interface then "AnyEvent::post_detect" (the |
937 | before or after loading AnyEvent), then they will be called directly |
951 | function). This variable is mainly useful for modules that can do |
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952 | something useful when AnyEvent is used and thus want to know when it |
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953 | is initialised, but do not need to even load it by default. This |
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954 | array provides the means to hook into AnyEvent passively, without |
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955 | loading it. |
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956 | |
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957 | Here is how it works: If there are any code references in this array |
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958 | (you can "push" to it before or after loading AnyEvent), then they |
938 | after the event loop has been chosen. |
959 | will be called directly after the event loop has been chosen. |
939 | |
960 | |
940 | You should check $AnyEvent::MODEL before adding to this array, |
961 | You should check $AnyEvent::MODEL before adding to this array, |
941 | though: if it is defined then the event loop has already been |
962 | though: if it is defined then the event loop has already been |
942 | detected, and the array will be ignored. |
963 | detected, and the array will be ignored. |
943 | |
964 | |
944 | Best use "AnyEvent::post_detect { BLOCK }" when your application |
965 | Best use "AnyEvent::post_detect { BLOCK }" when your application |
945 | allows it, as it takes care of these details. |
966 | allows it, as it takes care of these details. |
946 | |
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947 | This variable is mainly useful for modules that can do something |
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948 | useful when AnyEvent is used and thus want to know when it is |
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949 | initialised, but do not need to even load it by default. This array |
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950 | provides the means to hook into AnyEvent passively, without loading |
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951 | it. |
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952 | |
967 | |
953 | Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used |
968 | Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used |
954 | together, you could put this into Coro (this is the actual code used |
969 | together, you could put this into Coro (this is the actual code used |
955 | by Coro to accomplish this): |
970 | by Coro to accomplish this): |
956 | |
971 | |
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975 | To understand the usefulness of this function, consider a function |
990 | To understand the usefulness of this function, consider a function |
976 | that asynchronously does something for you and returns some |
991 | that asynchronously does something for you and returns some |
977 | transaction object or guard to let you cancel the operation. For |
992 | transaction object or guard to let you cancel the operation. For |
978 | example, "AnyEvent::Socket::tcp_connect": |
993 | example, "AnyEvent::Socket::tcp_connect": |
979 | |
994 | |
980 | # start a conenction attempt unless one is active |
995 | # start a connection attempt unless one is active |
981 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
996 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
982 | delete $self->{connect_guard}; |
997 | delete $self->{connect_guard}; |
983 | ... |
998 | ... |
984 | }; |
999 | }; |
985 | |
1000 | |
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1005 | if $some_error_condition; |
1020 | if $some_error_condition; |
1006 | |
1021 | |
1007 | AnyEvent::log $level, $msg[, @args] |
1022 | AnyEvent::log $level, $msg[, @args] |
1008 | Log the given $msg at the given $level. |
1023 | Log the given $msg at the given $level. |
1009 | |
1024 | |
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1025 | If AnyEvent::Log is not loaded then this function makes a simple |
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1026 | 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" - |
1027 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1011 | consequently, look at the AnyEvent::Log documentation for details. |
1028 | consequently, look at the AnyEvent::Log documentation for details. |
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1029 | |
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1030 | If the test fails it will simply return. Right now this happens when |
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1031 | a numerical loglevel is used and it is larger than the level |
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1032 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
1012 | |
1033 | |
1013 | If you want to sprinkle loads of logging calls around your code, |
1034 | If you want to sprinkle loads of logging calls around your code, |
1014 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1035 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1015 | function. |
1036 | function, which can reduce typing, codesize and can reduce the |
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1037 | logging overhead enourmously. |
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1038 | |
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1039 | AnyEvent::fh_block $filehandle |
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1040 | AnyEvent::fh_unblock $filehandle |
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1041 | Sets blocking or non-blocking behaviour for the given filehandle. |
1016 | |
1042 | |
1017 | WHAT TO DO IN A MODULE |
1043 | WHAT TO DO IN A MODULE |
1018 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1044 | 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. |
1045 | freely, but you should not load a specific event module or rely on it. |
1020 | |
1046 | |
… | |
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1079 | modules come as part of AnyEvent, the others are available via CPAN (see |
1105 | 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 |
1106 | <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 |
1107 | non-exhaustive list), and the list is heavily biased towards modules of |
1082 | the AnyEvent author himself :) |
1108 | the AnyEvent author himself :) |
1083 | |
1109 | |
1084 | AnyEvent::Util |
1110 | AnyEvent::Util (part of the AnyEvent distribution) |
1085 | Contains various utility functions that replace often-used blocking |
1111 | Contains various utility functions that replace often-used blocking |
1086 | functions such as "inet_aton" with event/callback-based versions. |
1112 | functions such as "inet_aton" with event/callback-based versions. |
1087 | |
1113 | |
1088 | AnyEvent::Socket |
1114 | AnyEvent::Socket (part of the AnyEvent distribution) |
1089 | Provides various utility functions for (internet protocol) sockets, |
1115 | Provides various utility functions for (internet protocol) sockets, |
1090 | addresses and name resolution. Also functions to create non-blocking |
1116 | addresses and name resolution. Also functions to create non-blocking |
1091 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1117 | tcp connections or tcp servers, with IPv6 and SRV record support and |
1092 | more. |
1118 | more. |
1093 | |
1119 | |
1094 | AnyEvent::Handle |
1120 | AnyEvent::Handle (part of the AnyEvent distribution) |
1095 | Provide read and write buffers, manages watchers for reads and |
1121 | Provide read and write buffers, manages watchers for reads and |
1096 | writes, supports raw and formatted I/O, I/O queued and fully |
1122 | writes, supports raw and formatted I/O, I/O queued and fully |
1097 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1123 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1098 | |
1124 | |
1099 | AnyEvent::DNS |
1125 | AnyEvent::DNS (part of the AnyEvent distribution) |
1100 | Provides rich asynchronous DNS resolver capabilities. |
1126 | Provides rich asynchronous DNS resolver capabilities. |
1101 | |
1127 | |
1102 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1128 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1103 | AnyEvent::IGS, AnyEvent::FCP |
1129 | AnyEvent::IGS, AnyEvent::FCP |
1104 | Implement event-based interfaces to the protocols of the same name |
1130 | 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 |
1131 | (for the curious, IGS is the International Go Server and FCP is the |
1106 | Freenet Client Protocol). |
1132 | Freenet Client Protocol). |
1107 | |
1133 | |
1108 | AnyEvent::Handle::UDP |
1134 | AnyEvent::AIO (part of the AnyEvent distribution) |
1109 | Here be danger! |
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1110 | |
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1111 | As Pauli would put it, "Not only is it not right, it's not even |
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1112 | wrong!" - there are so many things wrong with AnyEvent::Handle::UDP, |
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1113 | most notably its use of a stream-based API with a protocol that |
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1114 | isn't streamable, that the only way to improve it is to delete it. |
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1115 | |
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|
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 |
1135 | Truly asynchronous (as opposed to non-blocking) I/O, should be in |
1131 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1136 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1132 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1137 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1133 | event-based file I/O, and much more. |
1138 | event-based file I/O, and much more. |
1134 | |
1139 | |
|
|
1140 | AnyEvent::Fork, AnyEvent::Fork::RPC, AnyEvent::Fork::Pool, |
|
|
1141 | AnyEvent::Fork::Remote |
|
|
1142 | These let you safely fork new subprocesses, either locally or |
|
|
1143 | remotely (e.g.v ia ssh), using some RPC protocol or not, without the |
|
|
1144 | limitations normally imposed by fork (AnyEvent works fine for |
|
|
1145 | example). Dynamically-resized worker pools are obviously included as |
|
|
1146 | well. |
|
|
1147 | |
|
|
1148 | And they are quite tiny and fast as well - "abusing" AnyEvent::Fork |
|
|
1149 | just to exec external programs can easily beat using "fork" and |
|
|
1150 | "exec" (or even "system") in most programs. |
|
|
1151 | |
|
|
1152 | AnyEvent::Filesys::Notify |
|
|
1153 | AnyEvent is good for non-blocking stuff, but it can't detect file or |
|
|
1154 | path changes (e.g. "watch this directory for new files", "watch this |
|
|
1155 | file for changes"). The AnyEvent::Filesys::Notify module promises to |
|
|
1156 | do just that in a portbale fashion, supporting inotify on GNU/Linux |
|
|
1157 | and some weird, without doubt broken, stuff on OS X to monitor |
|
|
1158 | files. It can fall back to blocking scans at regular intervals |
|
|
1159 | transparently on other platforms, so it's about as portable as it |
|
|
1160 | gets. |
|
|
1161 | |
|
|
1162 | (I haven't used it myself, but it seems the biggest problem with it |
|
|
1163 | is it quite bad performance). |
|
|
1164 | |
1135 | AnyEvent::HTTPD |
1165 | AnyEvent::DBI |
1136 | A simple embedded webserver. |
1166 | Executes DBI requests asynchronously in a proxy process for you, |
|
|
1167 | notifying you in an event-based way when the operation is finished. |
1137 | |
1168 | |
1138 | AnyEvent::FastPing |
1169 | AnyEvent::FastPing |
1139 | The fastest ping in the west. |
1170 | The fastest ping in the west. |
1140 | |
1171 | |
1141 | Coro |
1172 | Coro |
1142 | Has special support for AnyEvent via Coro::AnyEvent. |
1173 | Has special support for AnyEvent via Coro::AnyEvent, which allows |
|
|
1174 | you to simply invert the flow control - don't call us, we will call |
|
|
1175 | you: |
|
|
1176 | |
|
|
1177 | async { |
|
|
1178 | Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it |
|
|
1179 | print "5 seconds later!\n"; |
|
|
1180 | |
|
|
1181 | Coro::AnyEvent::readable *STDIN; # uses an I/O watcher |
|
|
1182 | my $line = <STDIN>; # works for ttys |
|
|
1183 | |
|
|
1184 | AnyEvent::HTTP::http_get "url", Coro::rouse_cb; |
|
|
1185 | my ($body, $hdr) = Coro::rouse_wait; |
|
|
1186 | }; |
1143 | |
1187 | |
1144 | SIMPLIFIED AE API |
1188 | SIMPLIFIED AE API |
1145 | Starting with version 5.0, AnyEvent officially supports a second, much |
1189 | Starting with version 5.0, AnyEvent officially supports a second, much |
1146 | simpler, API that is designed to reduce the calling, typing and memory |
1190 | simpler, API that is designed to reduce the calling, typing and memory |
1147 | overhead by using function call syntax and a fixed number of parameters. |
1191 | overhead by using function call syntax and a fixed number of parameters. |
… | |
… | |
1163 | The pure perl event loop simply re-throws the exception (usually within |
1207 | The pure perl event loop simply re-throws the exception (usually within |
1164 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1208 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1165 | Glib uses "install_exception_handler" and so on. |
1209 | Glib uses "install_exception_handler" and so on. |
1166 | |
1210 | |
1167 | ENVIRONMENT VARIABLES |
1211 | ENVIRONMENT VARIABLES |
1168 | The following environment variables are used by this module or its |
1212 | AnyEvent supports a number of environment variables that tune the |
1169 | submodules. |
1213 | runtime behaviour. They are usually evaluated when AnyEvent is loaded, |
|
|
1214 | initialised, or a submodule that uses them is loaded. Many of them also |
|
|
1215 | cause AnyEvent to load additional modules - for example, |
|
|
1216 | "PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be |
|
|
1217 | loaded. |
1170 | |
1218 | |
1171 | Note that AnyEvent will remove *all* environment variables starting with |
1219 | All the environment variables documented here start with |
1172 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
1220 | "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace. |
1173 | enabled. |
1221 | Other modules are encouraged (but by no means required) to use |
|
|
1222 | "PERL_ANYEVENT_SUBMODULE" if they have registered the |
|
|
1223 | AnyEvent::Submodule namespace on CPAN, for any submodule. For example, |
|
|
1224 | AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it |
|
|
1225 | should not access env variables starting with "AE_", see below). |
|
|
1226 | |
|
|
1227 | All variables can also be set via the "AE_" prefix, that is, instead of |
|
|
1228 | setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case |
|
|
1229 | there is a clash btween anyevent and another program that uses |
|
|
1230 | "AE_something" you can set the corresponding "PERL_ANYEVENT_something" |
|
|
1231 | variable to the empty string, as those variables take precedence. |
|
|
1232 | |
|
|
1233 | When AnyEvent is first loaded, it copies all "AE_xxx" env variables to |
|
|
1234 | their "PERL_ANYEVENT_xxx" counterpart unless that variable already |
|
|
1235 | exists. If taint mode is on, then AnyEvent will remove *all* environment |
|
|
1236 | variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with |
|
|
1237 | "undef" or the empty string, if the corresaponding "AE_" variable is |
|
|
1238 | set). |
|
|
1239 | |
|
|
1240 | The exact algorithm is currently: |
|
|
1241 | |
|
|
1242 | 1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV |
|
|
1243 | 2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists |
|
|
1244 | 3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef. |
|
|
1245 | |
|
|
1246 | This ensures that child processes will not see the "AE_" variables. |
|
|
1247 | |
|
|
1248 | The following environment variables are currently known to AnyEvent: |
1174 | |
1249 | |
1175 | "PERL_ANYEVENT_VERBOSE" |
1250 | "PERL_ANYEVENT_VERBOSE" |
1176 | By default, AnyEvent will be completely silent except in fatal |
1251 | By default, AnyEvent will log messages with loglevel 4 ("error") or |
1177 | conditions. You can set this environment variable to make AnyEvent |
1252 | higher (see AnyEvent::Log). You can set this environment variable to |
1178 | more talkative. |
1253 | a numerical loglevel to make AnyEvent more (or less) talkative. |
1179 | |
1254 | |
|
|
1255 | If you want to do more than just set the global logging level you |
|
|
1256 | should have a look at "PERL_ANYEVENT_LOG", which allows much more |
|
|
1257 | complex specifications. |
|
|
1258 | |
|
|
1259 | When set to 0 ("off"), then no messages whatsoever will be logged |
|
|
1260 | with everything else at defaults. |
|
|
1261 | |
1180 | When set to 5 or higher, causes AnyEvent to warn about unexpected |
1262 | When set to 5 or higher ("warn"), AnyEvent warns about unexpected |
1181 | conditions, such as not being able to load the event model specified |
1263 | conditions, such as not being able to load the event model specified |
1182 | by "PERL_ANYEVENT_MODEL". |
1264 | by "PERL_ANYEVENT_MODEL", or a guard callback throwing an exception |
|
|
1265 | - this is the minimum recommended level for use during development. |
1183 | |
1266 | |
1184 | When set to 7 or higher, cause AnyEvent to report to STDERR which |
1267 | When set to 7 or higher (info), AnyEvent reports which event model |
1185 | event model it chooses. |
1268 | it chooses. |
1186 | |
1269 | |
1187 | When set to 8 or higher, then AnyEvent will report extra information |
1270 | When set to 8 or higher (debug), then AnyEvent will report extra |
1188 | on which optional modules it loads and how it implements certain |
1271 | information on which optional modules it loads and how it implements |
1189 | features. |
1272 | certain features. |
|
|
1273 | |
|
|
1274 | "PERL_ANYEVENT_LOG" |
|
|
1275 | Accepts rather complex logging specifications. For example, you |
|
|
1276 | could log all "debug" messages of some module to stderr, warnings |
|
|
1277 | and above to stderr, and errors and above to syslog, with: |
|
|
1278 | |
|
|
1279 | PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog |
|
|
1280 | |
|
|
1281 | For the rather extensive details, see AnyEvent::Log. |
|
|
1282 | |
|
|
1283 | This variable is evaluated when AnyEvent (or AnyEvent::Log) is |
|
|
1284 | loaded, so will take effect even before AnyEvent has initialised |
|
|
1285 | itself. |
|
|
1286 | |
|
|
1287 | Note that specifying this environment variable causes the |
|
|
1288 | AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE" |
|
|
1289 | does not, so only using the latter saves a few hundred kB of memory |
|
|
1290 | unless a module explicitly needs the extra features of |
|
|
1291 | AnyEvent::Log. |
1190 | |
1292 | |
1191 | "PERL_ANYEVENT_STRICT" |
1293 | "PERL_ANYEVENT_STRICT" |
1192 | AnyEvent does not do much argument checking by default, as thorough |
1294 | AnyEvent does not do much argument checking by default, as thorough |
1193 | argument checking is very costly. Setting this variable to a true |
1295 | argument checking is very costly. Setting this variable to a true |
1194 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1296 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
… | |
… | |
1201 | is definitely recommended to keep it off in production. Keeping |
1303 | is definitely recommended to keep it off in production. Keeping |
1202 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1304 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1203 | programs can be very useful, however. |
1305 | programs can be very useful, however. |
1204 | |
1306 | |
1205 | "PERL_ANYEVENT_DEBUG_SHELL" |
1307 | "PERL_ANYEVENT_DEBUG_SHELL" |
1206 | If this env variable is set, then its contents will be interpreted |
1308 | If this env variable is nonempty, then its contents will be |
1207 | by "AnyEvent::Socket::parse_hostport" (after replacing every |
1309 | interpreted by "AnyEvent::Socket::parse_hostport" and |
1208 | occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" |
1310 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
1209 | is bound on that port. The shell object is saved in |
1311 | the process pid). The shell object is saved in |
1210 | $AnyEvent::Debug::SHELL. |
1312 | $AnyEvent::Debug::SHELL. |
1211 | |
1313 | |
1212 | This takes place when the first watcher is created. |
1314 | This happens when the first watcher is created. |
1213 | |
1315 | |
1214 | For example, to bind a debug shell on a unix domain socket in |
1316 | For example, to bind a debug shell on a unix domain socket in |
1215 | /tmp/debug<pid>.sock, you could use this: |
1317 | /tmp/debug<pid>.sock, you could use this: |
1216 | |
1318 | |
1217 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
1319 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1320 | # connect with e.g.: socat readline /tmp/debug123.sock |
1218 | |
1321 | |
|
|
1322 | Or to bind to tcp port 4545 on localhost: |
|
|
1323 | |
|
|
1324 | PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog |
|
|
1325 | # connect with e.g.: telnet localhost 4545 |
|
|
1326 | |
1219 | Note that creating sockets in /tmp is very unsafe on multiuser |
1327 | Note that creating sockets in /tmp or on localhost is very unsafe on |
1220 | systems. |
1328 | multiuser systems. |
1221 | |
1329 | |
1222 | "PERL_ANYEVENT_DEBUG_WRAP" |
1330 | "PERL_ANYEVENT_DEBUG_WRAP" |
1223 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1331 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1224 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1332 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1225 | |
1333 | |
… | |
… | |
1241 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1349 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1242 | could start your program like this: |
1350 | could start your program like this: |
1243 | |
1351 | |
1244 | PERL_ANYEVENT_MODEL=Perl perl ... |
1352 | PERL_ANYEVENT_MODEL=Perl perl ... |
1245 | |
1353 | |
|
|
1354 | "PERL_ANYEVENT_IO_MODEL" |
|
|
1355 | The current file I/O model - see AnyEvent::IO for more info. |
|
|
1356 | |
|
|
1357 | At the moment, only "Perl" (small, pure-perl, synchronous) and |
|
|
1358 | "IOAIO" (truly asynchronous) are supported. The default is "IOAIO" |
|
|
1359 | if AnyEvent::AIO can be loaded, otherwise it is "Perl". |
|
|
1360 | |
1246 | "PERL_ANYEVENT_PROTOCOLS" |
1361 | "PERL_ANYEVENT_PROTOCOLS" |
1247 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1362 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1248 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1363 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1249 | change, or be the result of auto probing). |
1364 | change, or be the result of auto probing). |
1250 | |
1365 | |
… | |
… | |
1253 | mentioned will be used, and preference will be given to protocols |
1368 | mentioned will be used, and preference will be given to protocols |
1254 | mentioned earlier in the list. |
1369 | mentioned earlier in the list. |
1255 | |
1370 | |
1256 | This variable can effectively be used for denial-of-service attacks |
1371 | This variable can effectively be used for denial-of-service attacks |
1257 | against local programs (e.g. when setuid), although the impact is |
1372 | against local programs (e.g. when setuid), although the impact is |
1258 | likely small, as the program has to handle conenction and other |
1373 | likely small, as the program has to handle connection and other |
1259 | failures anyways. |
1374 | failures anyways. |
1260 | |
1375 | |
1261 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1376 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1262 | IPv6, but support both and try to use both. |
1377 | IPv6, but support both and try to use both. |
1263 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1378 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1264 | resolve or contact IPv6 addresses. |
1379 | resolve or contact IPv6 addresses. |
1265 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1380 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1266 | prefer IPv6 over IPv4. |
1381 | prefer IPv6 over IPv4. |
1267 | |
1382 | |
|
|
1383 | "PERL_ANYEVENT_HOSTS" |
|
|
1384 | This variable, if specified, overrides the /etc/hosts file used by |
|
|
1385 | AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be |
|
|
1386 | read from that file instead. |
|
|
1387 | |
1268 | "PERL_ANYEVENT_EDNS0" |
1388 | "PERL_ANYEVENT_EDNS0" |
1269 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1389 | Used by AnyEvent::DNS to decide whether to use the EDNS0 extension |
1270 | for DNS. This extension is generally useful to reduce DNS traffic, |
1390 | for DNS. This extension is generally useful to reduce DNS traffic, |
1271 | but some (broken) firewalls drop such DNS packets, which is why it |
1391 | especially when DNSSEC is involved, but some (broken) firewalls drop |
1272 | is off by default. |
1392 | such DNS packets, which is why it is off by default. |
1273 | |
1393 | |
1274 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1394 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1275 | EDNS0 in its DNS requests. |
1395 | EDNS0 in its DNS requests. |
1276 | |
1396 | |
1277 | "PERL_ANYEVENT_MAX_FORKS" |
1397 | "PERL_ANYEVENT_MAX_FORKS" |
… | |
… | |
1281 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1401 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1282 | The default value for the "max_outstanding" parameter for the |
1402 | The default value for the "max_outstanding" parameter for the |
1283 | default DNS resolver - this is the maximum number of parallel DNS |
1403 | default DNS resolver - this is the maximum number of parallel DNS |
1284 | requests that are sent to the DNS server. |
1404 | requests that are sent to the DNS server. |
1285 | |
1405 | |
|
|
1406 | "PERL_ANYEVENT_MAX_SIGNAL_LATENCY" |
|
|
1407 | Perl has inherently racy signal handling (you can basically choose |
|
|
1408 | between losing signals and memory corruption) - pure perl event |
|
|
1409 | loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't |
|
|
1410 | available) therefore have to poll regularly to avoid losing signals. |
|
|
1411 | |
|
|
1412 | Some event loops are racy, but don't poll regularly, and some event |
|
|
1413 | loops are written in C but are still racy. For those event loops, |
|
|
1414 | AnyEvent installs a timer that regularly wakes up the event loop. |
|
|
1415 | |
|
|
1416 | By default, the interval for this timer is 10 seconds, but you can |
|
|
1417 | override this delay with this environment variable (or by setting |
|
|
1418 | the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal |
|
|
1419 | watchers). |
|
|
1420 | |
|
|
1421 | Lower values increase CPU (and energy) usage, higher values can |
|
|
1422 | introduce long delays when reaping children or waiting for signals. |
|
|
1423 | |
|
|
1424 | The AnyEvent::Async module, if available, will be used to avoid this |
|
|
1425 | polling (with most event loops). |
|
|
1426 | |
1286 | "PERL_ANYEVENT_RESOLV_CONF" |
1427 | "PERL_ANYEVENT_RESOLV_CONF" |
1287 | The file to use instead of /etc/resolv.conf (or OS-specific |
1428 | The absolute path to a resolv.conf-style file to use instead of |
1288 | configuration) in the default resolver. When set to the empty |
1429 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1289 | string, no default config will be used. |
1430 | resolver, or the empty string to select the default configuration. |
1290 | |
1431 | |
1291 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1432 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1292 | When neither "ca_file" nor "ca_path" was specified during |
1433 | When neither "ca_file" nor "ca_path" was specified during |
1293 | AnyEvent::TLS context creation, and either of these environment |
1434 | AnyEvent::TLS context creation, and either of these environment |
1294 | variables exist, they will be used to specify CA certificate |
1435 | variables are nonempty, they will be used to specify CA certificate |
1295 | locations instead of a system-dependent default. |
1436 | locations instead of a system-dependent default. |
1296 | |
1437 | |
1297 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1438 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1298 | When these are set to 1, then the respective modules are not loaded. |
1439 | When these are set to 1, then the respective modules are not loaded. |
1299 | Mostly good for testing AnyEvent itself. |
1440 | Mostly good for testing AnyEvent itself. |
… | |
… | |
1471 | my $txn = shift; |
1612 | my $txn = shift; |
1472 | my $data = $txn->result; |
1613 | my $data = $txn->result; |
1473 | ... |
1614 | ... |
1474 | }); |
1615 | }); |
1475 | |
1616 | |
1476 | EV::loop; |
1617 | EV::run; |
1477 | |
1618 | |
1478 | 3b. The module user could use AnyEvent, too: |
1619 | 3b. The module user could use AnyEvent, too: |
1479 | |
1620 | |
1480 | use AnyEvent; |
1621 | use AnyEvent; |
1481 | |
1622 | |
… | |
… | |
1892 | This module is part of perl since release 5.008. It will be used |
2033 | 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 |
2034 | 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 |
2035 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1895 | load it to try to use a monotonic clock for timing stability. |
2036 | load it to try to use a monotonic clock for timing stability. |
1896 | |
2037 | |
|
|
2038 | AnyEvent::AIO (and IO::AIO) |
|
|
2039 | The default implementation of AnyEvent::IO is to do I/O |
|
|
2040 | synchronously, stopping programs while they access the disk, which |
|
|
2041 | is fine for a lot of programs. |
|
|
2042 | |
|
|
2043 | Installing AnyEvent::AIO (and its IO::AIO dependency) makes it |
|
|
2044 | switch to a true asynchronous implementation, so event processing |
|
|
2045 | can continue even while waiting for disk I/O. |
|
|
2046 | |
1897 | FORK |
2047 | FORK |
1898 | Most event libraries are not fork-safe. The ones who are usually are |
2048 | 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 |
2049 | 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 |
2050 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
1901 | epoll are usually badly thought-out hacks that are incompatible with |
2051 | epoll are usually badly thought-out hacks that are incompatible with |
… | |
… | |
1908 | usually happens when the first AnyEvent watcher is created, or the |
2058 | usually happens when the first AnyEvent watcher is created, or the |
1909 | library is loaded). |
2059 | library is loaded). |
1910 | |
2060 | |
1911 | If you have to fork, you must either do so *before* creating your first |
2061 | 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 |
2062 | 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. |
2063 | something completely out of the scope of AnyEvent (see below). |
1914 | |
2064 | |
1915 | The problem of doing event processing in the parent *and* the child is |
2065 | 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 |
2066 | 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 |
2067 | 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 |
2068 | 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 |
2069 | 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 |
2070 | start worker children from some kind of manage prrocess is usually |
1921 | preferred, because it is much easier and cleaner, at the expense of |
2071 | preferred, because it is much easier and cleaner, at the expense of |
1922 | having to have another binary. |
2072 | having to have another binary. |
|
|
2073 | |
|
|
2074 | In addition to logical problems with fork, there are also implementation |
|
|
2075 | problems. For example, on POSIX systems, you cannot fork at all in Perl |
|
|
2076 | code if a thread (I am talking of pthreads here) was ever created in the |
|
|
2077 | process, and this is just the tip of the iceberg. In general, using fork |
|
|
2078 | from Perl is difficult, and attempting to use fork without an exec to |
|
|
2079 | implement some kind of parallel processing is almost certainly doomed. |
|
|
2080 | |
|
|
2081 | To safely fork and exec, you should use a module such as Proc::FastSpawn |
|
|
2082 | that let's you safely fork and exec new processes. |
|
|
2083 | |
|
|
2084 | If you want to do multiprocessing using processes, you can look at the |
|
|
2085 | AnyEvent::Fork module (and some related modules such as |
|
|
2086 | AnyEvent::Fork::RPC, AnyEvent::Fork::Pool and AnyEvent::Fork::Remote). |
|
|
2087 | This module allows you to safely create subprocesses without any |
|
|
2088 | limitations - you can use X11 toolkits or AnyEvent in the children |
|
|
2089 | created by AnyEvent::Fork safely and without any special precautions. |
1923 | |
2090 | |
1924 | SECURITY CONSIDERATIONS |
2091 | SECURITY CONSIDERATIONS |
1925 | AnyEvent can be forced to load any event model via |
2092 | AnyEvent can be forced to load any event model via |
1926 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
2093 | $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 |
2094 | to execute arbitrary code or directly gain access, it can easily be used |
… | |
… | |
1962 | |
2129 | |
1963 | Development/Debugging: AnyEvent::Strict (stricter checking), |
2130 | Development/Debugging: AnyEvent::Strict (stricter checking), |
1964 | AnyEvent::Debug (interactive shell, watcher tracing). |
2131 | AnyEvent::Debug (interactive shell, watcher tracing). |
1965 | |
2132 | |
1966 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
2133 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
1967 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK. |
2134 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK, Cocoa::EventLoop, UV. |
1968 | |
2135 | |
1969 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
2136 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1970 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
2137 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1971 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
2138 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1972 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK. |
2139 | AnyEvent::Impl::IOAsync, AnyEvent::Impl::Irssi, AnyEvent::Impl::FLTK, |
|
|
2140 | AnyEvent::Impl::Cocoa, AnyEvent::Impl::UV. |
1973 | |
2141 | |
1974 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
2142 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
1975 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2143 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1976 | |
2144 | |
|
|
2145 | Asynchronous File I/O: AnyEvent::IO. |
|
|
2146 | |
1977 | Asynchronous DNS: AnyEvent::DNS. |
2147 | Asynchronous DNS: AnyEvent::DNS. |
1978 | |
2148 | |
1979 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2149 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
1980 | |
2150 | |
1981 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
2151 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
1982 | AnyEvent::HTTP. |
2152 | AnyEvent::HTTP. |
1983 | |
2153 | |
1984 | AUTHOR |
2154 | AUTHOR |
1985 | Marc Lehmann <schmorp@schmorp.de> |
2155 | Marc Lehmann <schmorp@schmorp.de> |
1986 | http://home.schmorp.de/ |
2156 | http://anyevent.schmorp.de |
1987 | |
2157 | |