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 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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80 | that isn't them. What's worse, all the potential users of your module |
81 | that isn't them. What's worse, all the potential users of your module |
81 | are *also* forced to use the same event loop you use. |
82 | are *also* forced to use the same event loop you use. |
82 | |
83 | |
83 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
84 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
84 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
85 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
85 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your |
86 | with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module |
86 | module uses one of those, every user of your module has to use it, too. |
87 | uses one of those, every user of your module has to use it, too. But if |
87 | But if your module uses AnyEvent, it works transparently with all event |
88 | your module uses AnyEvent, it works transparently with all event models |
88 | models it supports (including stuff like IO::Async, as long as those use |
89 | it supports (including stuff like IO::Async, as long as those use one of |
89 | one of the supported event loops. It is easy to add new event loops to |
90 | the supported event loops. It is easy to add new event loops to |
90 | AnyEvent, too, so it is future-proof). |
91 | AnyEvent, too, so it is future-proof). |
91 | |
92 | |
92 | In addition to being free of having to use *the one and only true event |
93 | In addition to being free of having to use *the one and only true event |
93 | model*, AnyEvent also is free of bloat and policy: with POE or similar |
94 | model*, AnyEvent also is free of bloat and policy: with POE or similar |
94 | modules, you get an enormous amount of code and strict rules you have to |
95 | modules, you get an enormous amount of code and strict rules you have to |
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115 | The interface itself is vaguely similar, but not identical to the Event |
116 | The interface itself is vaguely similar, but not identical to the Event |
116 | module. |
117 | module. |
117 | |
118 | |
118 | During the first call of any watcher-creation method, the module tries |
119 | During the first call of any watcher-creation method, the module tries |
119 | to detect the currently loaded event loop by probing whether one of the |
120 | to detect the currently loaded event loop by probing whether one of the |
120 | following modules is already loaded: EV, AnyEvent::Impl::Perl, Event, |
121 | following modules is already loaded: EV, AnyEvent::Loop, Event, Glib, |
121 | Glib, Tk, Event::Lib, Qt, POE. The first one found is used. If none are |
122 | Tk, Event::Lib, Qt, POE. The first one found is used. If none are |
122 | detected, the module tries to load the first four modules in the order |
123 | detected, the module tries to load the first four modules in the order |
123 | given; but note that if EV is not available, the pure-perl |
124 | given; but note that if EV is not available, the pure-perl |
124 | AnyEvent::Impl::Perl should always work, so the other two are not |
125 | AnyEvent::Loop should always work, so the other two are not normally |
125 | normally tried. |
126 | tried. |
126 | |
127 | |
127 | Because AnyEvent first checks for modules that are already loaded, |
128 | Because AnyEvent first checks for modules that are already loaded, |
128 | loading an event model explicitly before first using AnyEvent will |
129 | loading an event model explicitly before first using AnyEvent will |
129 | likely make that model the default. For example: |
130 | likely make that model the default. For example: |
130 | |
131 | |
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136 | The *likely* means that, if any module loads another event model and |
137 | The *likely* means that, if any module loads another event model and |
137 | starts using it, all bets are off - this case should be very rare |
138 | starts using it, all bets are off - this case should be very rare |
138 | though, as very few modules hardcode event loops without announcing this |
139 | though, as very few modules hardcode event loops without announcing this |
139 | very loudly. |
140 | very loudly. |
140 | |
141 | |
141 | The pure-perl implementation of AnyEvent is called |
142 | The pure-perl implementation of AnyEvent is called "AnyEvent::Loop". |
142 | "AnyEvent::Impl::Perl". Like other event modules you can load it |
143 | Like other event modules you can load it explicitly and enjoy the high |
143 | explicitly and enjoy the high availability of that event loop :) |
144 | availability of that event loop :) |
144 | |
145 | |
145 | WATCHERS |
146 | WATCHERS |
146 | AnyEvent has the central concept of a *watcher*, which is an object that |
147 | AnyEvent has the central concept of a *watcher*, which is an object that |
147 | stores relevant data for each kind of event you are waiting for, such as |
148 | stores relevant data for each kind of event you are waiting for, such as |
148 | the callback to call, the file handle to watch, etc. |
149 | the callback to call, the file handle to watch, etc. |
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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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347 | can get whatever behaviour you want with any event loop, by taking |
348 | can get whatever behaviour you want with any event loop, by taking |
348 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
349 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
349 | account. |
350 | account. |
350 | |
351 | |
351 | AnyEvent->now_update |
352 | AnyEvent->now_update |
352 | Some event loops (such as EV or AnyEvent::Impl::Perl) cache the |
353 | Some event loops (such as EV or AnyEvent::Loop) cache the current |
353 | current time for each loop iteration (see the discussion of |
354 | time for each loop iteration (see the discussion of AnyEvent->now, |
354 | AnyEvent->now, above). |
355 | above). |
355 | |
356 | |
356 | When a callback runs for a long time (or when the process sleeps), |
357 | When a callback runs for a long time (or when the process sleeps), |
357 | then this "current" time will differ substantially from the real |
358 | then this "current" time will differ substantially from the real |
358 | time, which might affect timers and time-outs. |
359 | time, which might affect timers and time-outs. |
359 | |
360 | |
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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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466 | This means you cannot create a child watcher as the very first thing in |
463 | This means you cannot create a child watcher as the very first thing in |
467 | an AnyEvent program, you *have* to create at least one watcher before |
464 | an AnyEvent program, you *have* to create at least one watcher before |
468 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
465 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
469 | |
466 | |
470 | As most event loops do not support waiting for child events, they will |
467 | As most event loops do not support waiting for child events, they will |
471 | be emulated by AnyEvent in most cases, in which the latency and race |
468 | be emulated by AnyEvent in most cases, in which case the latency and |
472 | problems mentioned in the description of signal watchers apply. |
469 | race problems mentioned in the description of signal watchers apply. |
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. |
815 | |
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. |
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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. |
820 | EV is the preferred backend when no other event loop seems to be in |
834 | EV is the preferred backend when no other event loop seems to be in |
821 | use. If EV is not installed, then AnyEvent will fall back to its own |
835 | use. If EV is not installed, then AnyEvent will fall back to its own |
822 | pure-perl implementation, which is available everywhere as it comes |
836 | pure-perl implementation, which is available everywhere as it comes |
823 | with AnyEvent itself. |
837 | with AnyEvent itself. |
824 | |
838 | |
825 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
839 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
826 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
840 | AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable. |
827 | |
841 | |
828 | Backends that are transparently being picked up when they are used. |
842 | Backends that are transparently being picked up when they are used. |
829 | These will be used if they are already loaded when the first watcher |
843 | These will be used if they are already loaded when the first watcher |
830 | is created, in which case it is assumed that the application is |
844 | is created, in which case it is assumed that the application is |
831 | using them. This means that AnyEvent will automatically pick the |
845 | using them. This means that AnyEvent will automatically pick the |
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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. |
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857 | AnyEvent::Impl::IOAsync based on IO::Async. |
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858 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
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859 | AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding). |
842 | |
860 | |
843 | Backends with special needs. |
861 | Backends with special needs. |
844 | Qt requires the Qt::Application to be instantiated first, but will |
862 | Qt requires the Qt::Application to be instantiated first, but will |
845 | otherwise be picked up automatically. As long as the main program |
863 | otherwise be picked up automatically. As long as the main program |
846 | instantiates the application before any AnyEvent watchers are |
864 | instantiates the application before any AnyEvent watchers are |
847 | created, everything should just work. |
865 | created, everything should just work. |
848 | |
866 | |
849 | AnyEvent::Impl::Qt based on Qt. |
867 | AnyEvent::Impl::Qt based on Qt. |
850 | |
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851 | Support for IO::Async can only be partial, as it is too broken and |
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852 | architecturally limited to even support the AnyEvent API. It also is |
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853 | the only event loop that needs the loop to be set explicitly, so it |
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854 | can only be used by a main program knowing about AnyEvent. See |
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855 | AnyEvent::Impl::IOAsync for the gory details. |
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856 | |
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857 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. |
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858 | |
868 | |
859 | Event loops that are indirectly supported via other backends. |
869 | Event loops that are indirectly supported via other backends. |
860 | Some event loops can be supported via other modules: |
870 | Some event loops can be supported via other modules: |
861 | |
871 | |
862 | There is no direct support for WxWidgets (Wx) or Prima. |
872 | There is no direct support for WxWidgets (Wx) or Prima. |
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891 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
901 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
892 | if necessary. You should only call this function right before you |
902 | if necessary. You should only call this function right before you |
893 | would have created an AnyEvent watcher anyway, that is, as late as |
903 | would have created an AnyEvent watcher anyway, that is, as late as |
894 | possible at runtime, and not e.g. during initialisation of your |
904 | possible at runtime, and not e.g. during initialisation of your |
895 | module. |
905 | module. |
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906 | |
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907 | The effect of calling this function is as if a watcher had been |
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908 | created (specifically, actions that happen "when the first watcher |
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909 | is created" happen when calling detetc as well). |
896 | |
910 | |
897 | If you need to do some initialisation before AnyEvent watchers are |
911 | If you need to do some initialisation before AnyEvent watchers are |
898 | created, use "post_detect". |
912 | created, use "post_detect". |
899 | |
913 | |
900 | $guard = AnyEvent::post_detect { BLOCK } |
914 | $guard = AnyEvent::post_detect { BLOCK } |
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962 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
976 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
963 | # as soon as it is |
977 | # as soon as it is |
964 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
978 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
965 | } |
979 | } |
966 | |
980 | |
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981 | AnyEvent::postpone { BLOCK } |
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982 | Arranges for the block to be executed as soon as possible, but not |
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983 | before the call itself returns. In practise, the block will be |
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984 | executed just before the event loop polls for new events, or shortly |
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985 | afterwards. |
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986 | |
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987 | This function never returns anything (to make the "return postpone { |
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988 | ... }" idiom more useful. |
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989 | |
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990 | To understand the usefulness of this function, consider a function |
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991 | that asynchronously does something for you and returns some |
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|
992 | transaction object or guard to let you cancel the operation. For |
|
|
993 | example, "AnyEvent::Socket::tcp_connect": |
|
|
994 | |
|
|
995 | # start a connection attempt unless one is active |
|
|
996 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
|
|
997 | delete $self->{connect_guard}; |
|
|
998 | ... |
|
|
999 | }; |
|
|
1000 | |
|
|
1001 | Imagine that this function could instantly call the callback, for |
|
|
1002 | example, because it detects an obvious error such as a negative port |
|
|
1003 | number. Invoking the callback before the function returns causes |
|
|
1004 | problems however: the callback will be called and will try to delete |
|
|
1005 | the guard object. But since the function hasn't returned yet, there |
|
|
1006 | is nothing to delete. When the function eventually returns it will |
|
|
1007 | assign the guard object to "$self->{connect_guard}", where it will |
|
|
1008 | likely never be deleted, so the program thinks it is still trying to |
|
|
1009 | connect. |
|
|
1010 | |
|
|
1011 | This is where "AnyEvent::postpone" should be used. Instead of |
|
|
1012 | calling the callback directly on error: |
|
|
1013 | |
|
|
1014 | $cb->(undef), return # signal error to callback, BAD! |
|
|
1015 | if $some_error_condition; |
|
|
1016 | |
|
|
1017 | It should use "postpone": |
|
|
1018 | |
|
|
1019 | AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later |
|
|
1020 | if $some_error_condition; |
|
|
1021 | |
|
|
1022 | AnyEvent::log $level, $msg[, @args] |
|
|
1023 | Log the given $msg at the given $level. |
|
|
1024 | |
|
|
1025 | If AnyEvent::Log is not loaded then this function makes a simple |
|
|
1026 | test to see whether the message will be logged. If the test succeeds |
|
|
1027 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
|
|
1028 | consequently, look at the AnyEvent::Log documentation for details. |
|
|
1029 | |
|
|
1030 | If the test fails it will simply return. Right now this happens when |
|
|
1031 | a numerical loglevel is used and it is larger than the level |
|
|
1032 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
|
|
1033 | |
|
|
1034 | If you want to sprinkle loads of logging calls around your code, |
|
|
1035 | consider creating a logger callback with the "AnyEvent::Log::logger" |
|
|
1036 | function, which can reduce typing, codesize and can reduce the |
|
|
1037 | logging overhead enourmously. |
|
|
1038 | |
|
|
1039 | AnyEvent::fh_block $filehandle |
|
|
1040 | AnyEvent::fh_unblock $filehandle |
|
|
1041 | Sets blocking or non-blocking behaviour for the given filehandle. |
|
|
1042 | |
967 | WHAT TO DO IN A MODULE |
1043 | WHAT TO DO IN A MODULE |
968 | 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 |
969 | 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. |
970 | |
1046 | |
971 | Be careful when you create watchers in the module body - AnyEvent will |
1047 | Be careful when you create watchers in the module body - AnyEvent will |
… | |
… | |
1001 | will decide on the event model to use as soon as it creates watchers, |
1077 | will decide on the event model to use as soon as it creates watchers, |
1002 | and it might choose the wrong one unless you load the correct one |
1078 | and it might choose the wrong one unless you load the correct one |
1003 | yourself. |
1079 | yourself. |
1004 | |
1080 | |
1005 | You can chose to use a pure-perl implementation by loading the |
1081 | You can chose to use a pure-perl implementation by loading the |
1006 | "AnyEvent::Impl::Perl" module, which gives you similar behaviour |
1082 | "AnyEvent::Loop" module, which gives you similar behaviour everywhere, |
1007 | everywhere, but letting AnyEvent chose the model is generally better. |
1083 | but letting AnyEvent chose the model is generally better. |
1008 | |
1084 | |
1009 | MAINLOOP EMULATION |
1085 | MAINLOOP EMULATION |
1010 | Sometimes (often for short test scripts, or even standalone programs who |
1086 | Sometimes (often for short test scripts, or even standalone programs who |
1011 | only want to use AnyEvent), you do not want to run a specific event |
1087 | only want to use AnyEvent), you do not want to run a specific event |
1012 | loop. |
1088 | loop. |
… | |
… | |
1024 | |
1100 | |
1025 | OTHER MODULES |
1101 | OTHER MODULES |
1026 | The following is a non-exhaustive list of additional modules that use |
1102 | The following is a non-exhaustive list of additional modules that use |
1027 | AnyEvent as a client and can therefore be mixed easily with other |
1103 | AnyEvent as a client and can therefore be mixed easily with other |
1028 | AnyEvent modules and other event loops in the same program. Some of the |
1104 | AnyEvent modules and other event loops in the same program. Some of the |
1029 | modules come as part of AnyEvent, the others are available via CPAN. |
1105 | modules come as part of AnyEvent, the others are available via CPAN (see |
|
|
1106 | <http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer |
|
|
1107 | non-exhaustive list), and the list is heavily biased towards modules of |
|
|
1108 | the AnyEvent author himself :) |
1030 | |
1109 | |
1031 | AnyEvent::Util |
1110 | AnyEvent::Util (part of the AnyEvent distribution) |
1032 | Contains various utility functions that replace often-used blocking |
1111 | Contains various utility functions that replace often-used blocking |
1033 | functions such as "inet_aton" with event/callback-based versions. |
1112 | functions such as "inet_aton" with event/callback-based versions. |
1034 | |
1113 | |
1035 | AnyEvent::Socket |
1114 | AnyEvent::Socket (part of the AnyEvent distribution) |
1036 | Provides various utility functions for (internet protocol) sockets, |
1115 | Provides various utility functions for (internet protocol) sockets, |
1037 | addresses and name resolution. Also functions to create non-blocking |
1116 | addresses and name resolution. Also functions to create non-blocking |
1038 | 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 |
1039 | more. |
1118 | more. |
1040 | |
1119 | |
1041 | AnyEvent::Handle |
1120 | AnyEvent::Handle (part of the AnyEvent distribution) |
1042 | Provide read and write buffers, manages watchers for reads and |
1121 | Provide read and write buffers, manages watchers for reads and |
1043 | 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 |
1044 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1123 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS). |
1045 | |
1124 | |
1046 | AnyEvent::DNS |
1125 | AnyEvent::DNS (part of the AnyEvent distribution) |
1047 | Provides rich asynchronous DNS resolver capabilities. |
1126 | Provides rich asynchronous DNS resolver capabilities. |
1048 | |
1127 | |
1049 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1128 | AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD, |
1050 | AnyEvent::IGS, AnyEvent::FCP |
1129 | AnyEvent::IGS, AnyEvent::FCP |
1051 | Implement event-based interfaces to the protocols of the same name |
1130 | Implement event-based interfaces to the protocols of the same name |
1052 | (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 |
1053 | Freenet Client Protocol). |
1132 | Freenet Client Protocol). |
1054 | |
1133 | |
1055 | AnyEvent::Handle::UDP |
1134 | AnyEvent::AIO (part of the AnyEvent distribution) |
1056 | Here be danger! |
|
|
1057 | |
|
|
1058 | As Pauli would put it, "Not only is it not right, it's not even |
|
|
1059 | wrong!" - there are so many things wrong with AnyEvent::Handle::UDP, |
|
|
1060 | most notably its use of a stream-based API with a protocol that |
|
|
1061 | isn't streamable, that the only way to improve it is to delete it. |
|
|
1062 | |
|
|
1063 | It features data corruption (but typically only under load) and |
|
|
1064 | general confusion. On top, the author is not only clueless about UDP |
|
|
1065 | but also fact-resistant - some gems of his understanding: "connect |
|
|
1066 | doesn't work with UDP", "UDP packets are not IP packets", "UDP only |
|
|
1067 | has datagrams, not packets", "I don't need to implement proper error |
|
|
1068 | checking as UDP doesn't support error checking" and so on - he |
|
|
1069 | doesn't even understand what's wrong with his module when it is |
|
|
1070 | explained to him. |
|
|
1071 | |
|
|
1072 | AnyEvent::DBI |
|
|
1073 | Executes DBI requests asynchronously in a proxy process for you, |
|
|
1074 | notifying you in an event-based way when the operation is finished. |
|
|
1075 | |
|
|
1076 | AnyEvent::AIO |
|
|
1077 | 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 |
1078 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1136 | the toolbox of every event programmer. AnyEvent::AIO transparently |
1079 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1137 | fuses IO::AIO and AnyEvent together, giving AnyEvent access to |
1080 | event-based file I/O, and much more. |
1138 | event-based file I/O, and much more. |
1081 | |
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 | |
1082 | AnyEvent::HTTPD |
1165 | AnyEvent::DBI |
1083 | 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. |
1084 | |
1168 | |
1085 | AnyEvent::FastPing |
1169 | AnyEvent::FastPing |
1086 | The fastest ping in the west. |
1170 | The fastest ping in the west. |
1087 | |
1171 | |
1088 | Coro |
1172 | Coro |
1089 | 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, $hdr) = Coro::rouse_wait; |
|
|
1186 | }; |
1090 | |
1187 | |
1091 | SIMPLIFIED AE API |
1188 | SIMPLIFIED AE API |
1092 | Starting with version 5.0, AnyEvent officially supports a second, much |
1189 | Starting with version 5.0, AnyEvent officially supports a second, much |
1093 | simpler, API that is designed to reduce the calling, typing and memory |
1190 | simpler, API that is designed to reduce the calling, typing and memory |
1094 | overhead by using function call syntax and a fixed number of parameters. |
1191 | overhead by using function call syntax and a fixed number of parameters. |
… | |
… | |
1110 | The pure perl event loop simply re-throws the exception (usually within |
1207 | The pure perl event loop simply re-throws the exception (usually within |
1111 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1208 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
1112 | Glib uses "install_exception_handler" and so on. |
1209 | Glib uses "install_exception_handler" and so on. |
1113 | |
1210 | |
1114 | ENVIRONMENT VARIABLES |
1211 | ENVIRONMENT VARIABLES |
1115 | The following environment variables are used by this module or its |
1212 | AnyEvent supports a number of environment variables that tune the |
1116 | 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. |
1117 | |
1218 | |
1118 | Note that AnyEvent will remove *all* environment variables starting with |
1219 | All the environment variables documented here start with |
1119 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
1220 | "PERL_ANYEVENT_", which is what AnyEvent considers its own namespace. |
1120 | 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: |
1121 | |
1249 | |
1122 | "PERL_ANYEVENT_VERBOSE" |
1250 | "PERL_ANYEVENT_VERBOSE" |
1123 | By default, AnyEvent will be completely silent except in fatal |
1251 | By default, AnyEvent will log messages with loglevel 4 ("error") or |
1124 | conditions. You can set this environment variable to make AnyEvent |
1252 | higher (see AnyEvent::Log). You can set this environment variable to |
1125 | more talkative. |
1253 | a numerical loglevel to make AnyEvent more (or less) talkative. |
1126 | |
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 | |
1127 | When set to 1 or higher, causes AnyEvent to warn about unexpected |
1262 | When set to 5 or higher ("warn"), AnyEvent warns about unexpected |
1128 | 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 |
1129 | 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. |
1130 | |
1266 | |
1131 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
1267 | When set to 7 or higher (info), AnyEvent reports which event model |
1132 | event model it chooses. |
1268 | it chooses. |
1133 | |
1269 | |
1134 | 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 |
1135 | on which optional modules it loads and how it implements certain |
1271 | information on which optional modules it loads and how it implements |
1136 | 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. |
1137 | |
1292 | |
1138 | "PERL_ANYEVENT_STRICT" |
1293 | "PERL_ANYEVENT_STRICT" |
1139 | AnyEvent does not do much argument checking by default, as thorough |
1294 | AnyEvent does not do much argument checking by default, as thorough |
1140 | argument checking is very costly. Setting this variable to a true |
1295 | argument checking is very costly. Setting this variable to a true |
1141 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1296 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
… | |
… | |
1147 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1302 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1148 | is definitely recommended to keep it off in production. Keeping |
1303 | is definitely recommended to keep it off in production. Keeping |
1149 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1304 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1150 | programs can be very useful, however. |
1305 | programs can be very useful, however. |
1151 | |
1306 | |
|
|
1307 | "PERL_ANYEVENT_DEBUG_SHELL" |
|
|
1308 | If this env variable is nonempty, then its contents will be |
|
|
1309 | interpreted by "AnyEvent::Socket::parse_hostport" and |
|
|
1310 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
|
|
1311 | the process pid). The shell object is saved in |
|
|
1312 | $AnyEvent::Debug::SHELL. |
|
|
1313 | |
|
|
1314 | This happens when the first watcher is created. |
|
|
1315 | |
|
|
1316 | For example, to bind a debug shell on a unix domain socket in |
|
|
1317 | /tmp/debug<pid>.sock, you could use this: |
|
|
1318 | |
|
|
1319 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1320 | # connect with e.g.: socat readline /tmp/debug123.sock |
|
|
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 | |
|
|
1327 | Note that creating sockets in /tmp or on localhost is very unsafe on |
|
|
1328 | multiuser systems. |
|
|
1329 | |
|
|
1330 | "PERL_ANYEVENT_DEBUG_WRAP" |
|
|
1331 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
|
|
1332 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
|
|
1333 | |
1152 | "PERL_ANYEVENT_MODEL" |
1334 | "PERL_ANYEVENT_MODEL" |
1153 | This can be used to specify the event model to be used by AnyEvent, |
1335 | This can be used to specify the event model to be used by AnyEvent, |
1154 | before auto detection and -probing kicks in. It must be a string |
1336 | before auto detection and -probing kicks in. |
1155 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1337 | |
1156 | gets prepended and the resulting module name is loaded and if the |
1338 | It normally is a string consisting entirely of ASCII letters (e.g. |
1157 | load was successful, used as event model. If it fails to load |
1339 | "EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and |
|
|
1340 | the resulting module name is loaded and - if the load was successful |
|
|
1341 | - used as event model backend. If it fails to load then AnyEvent |
1158 | AnyEvent will proceed with auto detection and -probing. |
1342 | will proceed with auto detection and -probing. |
1159 | |
1343 | |
1160 | This functionality might change in future versions. |
1344 | If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::") |
|
|
1345 | then nothing gets prepended and the module name is used as-is (hint: |
|
|
1346 | "::" at the end of a string designates a module name and quotes it |
|
|
1347 | appropriately). |
1161 | |
1348 | |
1162 | For example, to force the pure perl model (AnyEvent::Impl::Perl) you |
1349 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1163 | could start your program like this: |
1350 | could start your program like this: |
1164 | |
1351 | |
1165 | PERL_ANYEVENT_MODEL=Perl perl ... |
1352 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
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". |
1166 | |
1360 | |
1167 | "PERL_ANYEVENT_PROTOCOLS" |
1361 | "PERL_ANYEVENT_PROTOCOLS" |
1168 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1362 | Used by both AnyEvent::DNS and AnyEvent::Socket to determine |
1169 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1363 | preferences for IPv4 or IPv6. The default is unspecified (and might |
1170 | change, or be the result of auto probing). |
1364 | change, or be the result of auto probing). |
… | |
… | |
1174 | mentioned will be used, and preference will be given to protocols |
1368 | mentioned will be used, and preference will be given to protocols |
1175 | mentioned earlier in the list. |
1369 | mentioned earlier in the list. |
1176 | |
1370 | |
1177 | This variable can effectively be used for denial-of-service attacks |
1371 | This variable can effectively be used for denial-of-service attacks |
1178 | against local programs (e.g. when setuid), although the impact is |
1372 | against local programs (e.g. when setuid), although the impact is |
1179 | likely small, as the program has to handle conenction and other |
1373 | likely small, as the program has to handle connection and other |
1180 | failures anyways. |
1374 | failures anyways. |
1181 | |
1375 | |
1182 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1376 | Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over |
1183 | IPv6, but support both and try to use both. |
1377 | IPv6, but support both and try to use both. |
1184 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1378 | "PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to |
1185 | resolve or contact IPv6 addresses. |
1379 | resolve or contact IPv6 addresses. |
1186 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1380 | "PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but |
1187 | prefer IPv6 over IPv4. |
1381 | prefer IPv6 over IPv4. |
1188 | |
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 | |
1189 | "PERL_ANYEVENT_EDNS0" |
1388 | "PERL_ANYEVENT_EDNS0" |
1190 | 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 |
1191 | for DNS. This extension is generally useful to reduce DNS traffic, |
1390 | for DNS. This extension is generally useful to reduce DNS traffic, |
1192 | but some (broken) firewalls drop such DNS packets, which is why it |
1391 | especially when DNSSEC is involved, but some (broken) firewalls drop |
1193 | is off by default. |
1392 | such DNS packets, which is why it is off by default. |
1194 | |
1393 | |
1195 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1394 | Setting this variable to 1 will cause AnyEvent::DNS to announce |
1196 | EDNS0 in its DNS requests. |
1395 | EDNS0 in its DNS requests. |
1197 | |
1396 | |
1198 | "PERL_ANYEVENT_MAX_FORKS" |
1397 | "PERL_ANYEVENT_MAX_FORKS" |
… | |
… | |
1202 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1401 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1203 | The default value for the "max_outstanding" parameter for the |
1402 | The default value for the "max_outstanding" parameter for the |
1204 | default DNS resolver - this is the maximum number of parallel DNS |
1403 | default DNS resolver - this is the maximum number of parallel DNS |
1205 | requests that are sent to the DNS server. |
1404 | requests that are sent to the DNS server. |
1206 | |
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 | |
1207 | "PERL_ANYEVENT_RESOLV_CONF" |
1427 | "PERL_ANYEVENT_RESOLV_CONF" |
1208 | 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 |
1209 | configuration) in the default resolver. When set to the empty |
1429 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1210 | string, no default config will be used. |
1430 | resolver, or the empty string to select the default configuration. |
1211 | |
1431 | |
1212 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1432 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1213 | When neither "ca_file" nor "ca_path" was specified during |
1433 | When neither "ca_file" nor "ca_path" was specified during |
1214 | AnyEvent::TLS context creation, and either of these environment |
1434 | AnyEvent::TLS context creation, and either of these environment |
1215 | variables exist, they will be used to specify CA certificate |
1435 | variables are nonempty, they will be used to specify CA certificate |
1216 | locations instead of a system-dependent default. |
1436 | locations instead of a system-dependent default. |
1217 | |
1437 | |
1218 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1438 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
1219 | 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. |
1220 | Mostly good for testing AnyEvent itself. |
1440 | Mostly good for testing AnyEvent itself. |
… | |
… | |
1392 | my $txn = shift; |
1612 | my $txn = shift; |
1393 | my $data = $txn->result; |
1613 | my $data = $txn->result; |
1394 | ... |
1614 | ... |
1395 | }); |
1615 | }); |
1396 | |
1616 | |
1397 | EV::loop; |
1617 | EV::run; |
1398 | |
1618 | |
1399 | 3b. The module user could use AnyEvent, too: |
1619 | 3b. The module user could use AnyEvent, too: |
1400 | |
1620 | |
1401 | use AnyEvent; |
1621 | use AnyEvent; |
1402 | |
1622 | |
… | |
… | |
1540 | when used without AnyEvent), but most event loops have acceptable |
1760 | when used without AnyEvent), but most event loops have acceptable |
1541 | performance with or without AnyEvent. |
1761 | performance with or without AnyEvent. |
1542 | |
1762 | |
1543 | * The overhead AnyEvent adds is usually much smaller than the overhead |
1763 | * The overhead AnyEvent adds is usually much smaller than the overhead |
1544 | of the actual event loop, only with extremely fast event loops such |
1764 | of the actual event loop, only with extremely fast event loops such |
1545 | as EV adds AnyEvent significant overhead. |
1765 | as EV does AnyEvent add significant overhead. |
1546 | |
1766 | |
1547 | * You should avoid POE like the plague if you want performance or |
1767 | * You should avoid POE like the plague if you want performance or |
1548 | reasonable memory usage. |
1768 | reasonable memory usage. |
1549 | |
1769 | |
1550 | BENCHMARKING THE LARGE SERVER CASE |
1770 | BENCHMARKING THE LARGE SERVER CASE |
… | |
… | |
1810 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
2030 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
1811 | |
2031 | |
1812 | Time::HiRes |
2032 | Time::HiRes |
1813 | 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 |
1814 | 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 |
1815 | its own. The pure-perl event loop (AnyEvent::Impl::Perl) will |
2035 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1816 | additionally use it to try to use a monotonic clock for timing |
2036 | load it to try to use a monotonic clock for timing stability. |
1817 | stability. |
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. |
1818 | |
2046 | |
1819 | FORK |
2047 | FORK |
1820 | 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 |
1821 | 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 |
1822 | - 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 |
… | |
… | |
1830 | usually happens when the first AnyEvent watcher is created, or the |
2058 | usually happens when the first AnyEvent watcher is created, or the |
1831 | library is loaded). |
2059 | library is loaded). |
1832 | |
2060 | |
1833 | 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 |
1834 | 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 |
1835 | something completely out of the scope of AnyEvent. |
2063 | something completely out of the scope of AnyEvent (see below). |
1836 | |
2064 | |
1837 | 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 |
1838 | much more complicated: even for backends that *are* fork-aware or |
2066 | much more complicated: even for backends that *are* fork-aware or |
1839 | 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 |
1840 | 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 |
1841 | 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 |
1842 | start worker children from some kind of manage rprocess is usually |
2070 | start worker children from some kind of manage prrocess is usually |
1843 | 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 |
1844 | 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. |
1845 | |
2090 | |
1846 | SECURITY CONSIDERATIONS |
2091 | SECURITY CONSIDERATIONS |
1847 | AnyEvent can be forced to load any event model via |
2092 | AnyEvent can be forced to load any event model via |
1848 | $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 |
1849 | 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 |
… | |
… | |
1877 | SEE ALSO |
2122 | SEE ALSO |
1878 | Tutorial/Introduction: AnyEvent::Intro. |
2123 | Tutorial/Introduction: AnyEvent::Intro. |
1879 | |
2124 | |
1880 | FAQ: AnyEvent::FAQ. |
2125 | FAQ: AnyEvent::FAQ. |
1881 | |
2126 | |
1882 | Utility functions: AnyEvent::Util. |
2127 | Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log |
|
|
2128 | (simply logging). |
1883 | |
2129 | |
1884 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
2130 | Development/Debugging: AnyEvent::Strict (stricter checking), |
1885 | Event::Lib, Qt, POE. |
2131 | AnyEvent::Debug (interactive shell, watcher tracing). |
|
|
2132 | |
|
|
2133 | Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
|
|
2134 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK, Cocoa::EventLoop, UV. |
1886 | |
2135 | |
1887 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
2136 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1888 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
2137 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1889 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
2138 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
|
|
2139 | AnyEvent::Impl::IOAsync, AnyEvent::Impl::Irssi, AnyEvent::Impl::FLTK, |
1890 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |
2140 | AnyEvent::Impl::Cocoa, AnyEvent::Impl::UV. |
1891 | |
2141 | |
1892 | Non-blocking file handles, sockets, TCP clients and servers: |
2142 | Non-blocking handles, pipes, stream sockets, TCP clients and servers: |
1893 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
2143 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
|
|
2144 | |
|
|
2145 | Asynchronous File I/O: AnyEvent::IO. |
1894 | |
2146 | |
1895 | Asynchronous DNS: AnyEvent::DNS. |
2147 | Asynchronous DNS: AnyEvent::DNS. |
1896 | |
2148 | |
1897 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
2149 | Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event. |
1898 | |
2150 | |
1899 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
2151 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC, |
1900 | AnyEvent::HTTP. |
2152 | AnyEvent::HTTP. |
1901 | |
2153 | |
1902 | AUTHOR |
2154 | AUTHOR |
1903 | Marc Lehmann <schmorp@schmorp.de> |
2155 | Marc Lehmann <schmorp@schmorp.de> |
1904 | http://home.schmorp.de/ |
2156 | http://anyevent.schmorp.de |
1905 | |
2157 | |