1 | =head1 NAME |
1 | =head1 => NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
… | |
… | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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20 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
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22 | |
22 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
24 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
26 | nowadays. So what is different about AnyEvent? |
… | |
… | |
57 | as those use one of the supported event loops. It is trivial to add new |
57 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
58 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
59 | |
60 | In addition to being free of having to use I<the one and only true event |
60 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
62 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
65 | technically possible. |
66 | |
66 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
68 | useful) and you want to force your users to use the one and only event |
68 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
69 | model, you should I<not> use this module. |
70 | |
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71 | |
70 | |
72 | =head1 DESCRIPTION |
71 | =head1 DESCRIPTION |
73 | |
72 | |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
73 | L<AnyEvent> provides an identical interface to multiple event loops. This |
75 | allows module authors to utilise an event loop without forcing module |
74 | allows module authors to utilise an event loop without forcing module |
… | |
… | |
79 | The interface itself is vaguely similar, but not identical to the L<Event> |
78 | The interface itself is vaguely similar, but not identical to the L<Event> |
80 | module. |
79 | module. |
81 | |
80 | |
82 | During the first call of any watcher-creation method, the module tries |
81 | During the first call of any watcher-creation method, the module tries |
83 | to detect the currently loaded event loop by probing whether one of the |
82 | to detect the currently loaded event loop by probing whether one of the |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
83 | following modules is already loaded: L<EV>, |
85 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
84 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
86 | L<POE>. The first one found is used. If none are found, the module tries |
85 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
86 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
88 | adaptor should always succeed) in the order given. The first one that can |
87 | adaptor should always succeed) in the order given. The first one that can |
89 | be successfully loaded will be used. If, after this, still none could be |
88 | be successfully loaded will be used. If, after this, still none could be |
… | |
… | |
109 | |
108 | |
110 | =head1 WATCHERS |
109 | =head1 WATCHERS |
111 | |
110 | |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
113 | stores relevant data for each kind of event you are waiting for, such as |
112 | stores relevant data for each kind of event you are waiting for, such as |
114 | the callback to call, the filehandle to watch, etc. |
113 | the callback to call, the file handle to watch, etc. |
115 | |
114 | |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
117 | creating a watcher it will immediately "watch" for events and invoke the |
116 | creating a watcher it will immediately "watch" for events and invoke the |
118 | callback when the event occurs (of course, only when the event model |
117 | callback when the event occurs (of course, only when the event model |
119 | is in control). |
118 | is in control). |
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238 | |
237 | |
239 | Although the callback might get passed parameters, their value and |
238 | Although the callback might get passed parameters, their value and |
240 | presence is undefined and you cannot rely on them. Portable AnyEvent |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
241 | callbacks cannot use arguments passed to signal watcher callbacks. |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
242 | |
241 | |
243 | Multiple signal occurances can be clumped together into one callback |
242 | Multiple signal occurrences can be clumped together into one callback |
244 | invocation, and callback invocation will be synchronous. synchronous means |
243 | invocation, and callback invocation will be synchronous. Synchronous means |
245 | that it might take a while until the signal gets handled by the process, |
244 | that it might take a while until the signal gets handled by the process, |
246 | but it is guarenteed not to interrupt any other callbacks. |
245 | but it is guaranteed not to interrupt any other callbacks. |
247 | |
246 | |
248 | The main advantage of using these watchers is that you can share a signal |
247 | The main advantage of using these watchers is that you can share a signal |
249 | between multiple watchers. |
248 | between multiple watchers. |
250 | |
249 | |
251 | This watcher might use C<%SIG>, so programs overwriting those signals |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
… | |
280 | |
279 | |
281 | Example: fork a process and wait for it |
280 | Example: fork a process and wait for it |
282 | |
281 | |
283 | my $done = AnyEvent->condvar; |
282 | my $done = AnyEvent->condvar; |
284 | |
283 | |
285 | AnyEvent::detect; # force event module to be initialised |
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286 | |
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287 | my $pid = fork or exit 5; |
284 | my $pid = fork or exit 5; |
288 | |
285 | |
289 | my $w = AnyEvent->child ( |
286 | my $w = AnyEvent->child ( |
290 | pid => $pid, |
287 | pid => $pid, |
291 | cb => sub { |
288 | cb => sub { |
292 | my ($pid, $status) = @_; |
289 | my ($pid, $status) = @_; |
293 | warn "pid $pid exited with status $status"; |
290 | warn "pid $pid exited with status $status"; |
294 | $done->broadcast; |
291 | $done->send; |
295 | }, |
292 | }, |
296 | ); |
293 | ); |
297 | |
294 | |
298 | # do something else, then wait for process exit |
295 | # do something else, then wait for process exit |
299 | $done->wait; |
296 | $done->recv; |
300 | |
297 | |
301 | =head2 CONDITION VARIABLES |
298 | =head2 CONDITION VARIABLES |
302 | |
299 | |
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300 | If you are familiar with some event loops you will know that all of them |
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301 | require you to run some blocking "loop", "run" or similar function that |
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302 | will actively watch for new events and call your callbacks. |
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303 | |
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304 | AnyEvent is different, it expects somebody else to run the event loop and |
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305 | will only block when necessary (usually when told by the user). |
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306 | |
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307 | The instrument to do that is called a "condition variable", so called |
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308 | because they represent a condition that must become true. |
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309 | |
303 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
310 | Condition variables can be created by calling the C<< AnyEvent->condvar |
304 | method without any arguments. |
311 | >> method, usually without arguments. The only argument pair allowed is |
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312 | C<cb>, which specifies a callback to be called when the condition variable |
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313 | becomes true. |
305 | |
314 | |
306 | A condition variable waits for a condition - precisely that the C<< |
315 | After creation, the condition variable is "false" until it becomes "true" |
307 | ->broadcast >> method has been called. |
316 | by calling the C<send> method (or calling the condition variable as if it |
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317 | were a callback). |
308 | |
318 | |
309 | They are very useful to signal that a condition has been fulfilled, for |
319 | Condition variables are similar to callbacks, except that you can |
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320 | optionally wait for them. They can also be called merge points - points |
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321 | in time where multiple outstanding events have been processed. And yet |
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322 | another way to call them is transactions - each condition variable can be |
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323 | used to represent a transaction, which finishes at some point and delivers |
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324 | a result. |
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325 | |
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326 | Condition variables are very useful to signal that something has finished, |
310 | example, if you write a module that does asynchronous http requests, |
327 | for example, if you write a module that does asynchronous http requests, |
311 | then a condition variable would be the ideal candidate to signal the |
328 | then a condition variable would be the ideal candidate to signal the |
312 | availability of results. |
329 | availability of results. The user can either act when the callback is |
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330 | called or can synchronously C<< ->recv >> for the results. |
313 | |
331 | |
314 | You can also use condition variables to block your main program until |
332 | You can also use them to simulate traditional event loops - for example, |
315 | an event occurs - for example, you could C<< ->wait >> in your main |
333 | you can block your main program until an event occurs - for example, you |
316 | program until the user clicks the Quit button in your app, which would C<< |
334 | could C<< ->recv >> in your main program until the user clicks the Quit |
317 | ->broadcast >> the "quit" event. |
335 | button of your app, which would C<< ->send >> the "quit" event. |
318 | |
336 | |
319 | Note that condition variables recurse into the event loop - if you have |
337 | Note that condition variables recurse into the event loop - if you have |
320 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
338 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
321 | lose. Therefore, condition variables are good to export to your caller, but |
339 | lose. Therefore, condition variables are good to export to your caller, but |
322 | you should avoid making a blocking wait yourself, at least in callbacks, |
340 | you should avoid making a blocking wait yourself, at least in callbacks, |
323 | as this asks for trouble. |
341 | as this asks for trouble. |
324 | |
342 | |
325 | This object has two methods: |
343 | Condition variables are represented by hash refs in perl, and the keys |
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344 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
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345 | easy (it is often useful to build your own transaction class on top of |
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346 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
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347 | it's C<new> method in your own C<new> method. |
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348 | |
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349 | There are two "sides" to a condition variable - the "producer side" which |
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350 | eventually calls C<< -> send >>, and the "consumer side", which waits |
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351 | for the send to occur. |
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352 | |
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353 | Example: wait for a timer. |
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354 | |
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355 | # wait till the result is ready |
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356 | my $result_ready = AnyEvent->condvar; |
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357 | |
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358 | # do something such as adding a timer |
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359 | # or socket watcher the calls $result_ready->send |
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360 | # when the "result" is ready. |
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361 | # in this case, we simply use a timer: |
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362 | my $w = AnyEvent->timer ( |
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363 | after => 1, |
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364 | cb => sub { $result_ready->send }, |
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365 | ); |
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366 | |
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367 | # this "blocks" (while handling events) till the callback |
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368 | # calls send |
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369 | $result_ready->recv; |
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370 | |
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371 | Example: wait for a timer, but take advantage of the fact that |
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372 | condition variables are also code references. |
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373 | |
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374 | my $done = AnyEvent->condvar; |
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375 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
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376 | $done->recv; |
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377 | |
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378 | =head3 METHODS FOR PRODUCERS |
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379 | |
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380 | These methods should only be used by the producing side, i.e. the |
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381 | code/module that eventually sends the signal. Note that it is also |
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382 | the producer side which creates the condvar in most cases, but it isn't |
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383 | uncommon for the consumer to create it as well. |
326 | |
384 | |
327 | =over 4 |
385 | =over 4 |
328 | |
386 | |
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387 | =item $cv->send (...) |
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388 | |
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389 | Flag the condition as ready - a running C<< ->recv >> and all further |
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390 | calls to C<recv> will (eventually) return after this method has been |
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391 | called. If nobody is waiting the send will be remembered. |
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392 | |
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393 | If a callback has been set on the condition variable, it is called |
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394 | immediately from within send. |
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395 | |
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396 | Any arguments passed to the C<send> call will be returned by all |
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397 | future C<< ->recv >> calls. |
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398 | |
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399 | Condition variables are overloaded so one can call them directly (as a |
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400 | code reference). Calling them directly is the same as calling C<send>. |
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401 | |
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402 | =item $cv->croak ($error) |
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403 | |
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404 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
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405 | C<Carp::croak> with the given error message/object/scalar. |
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406 | |
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407 | This can be used to signal any errors to the condition variable |
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408 | user/consumer. |
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409 | |
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410 | =item $cv->begin ([group callback]) |
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411 | |
329 | =item $cv->wait |
412 | =item $cv->end |
330 | |
413 | |
331 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
414 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
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415 | |
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416 | These two methods can be used to combine many transactions/events into |
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417 | one. For example, a function that pings many hosts in parallel might want |
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418 | to use a condition variable for the whole process. |
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419 | |
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420 | Every call to C<< ->begin >> will increment a counter, and every call to |
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421 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
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422 | >>, the (last) callback passed to C<begin> will be executed. That callback |
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423 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
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424 | callback was set, C<send> will be called without any arguments. |
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425 | |
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426 | Let's clarify this with the ping example: |
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427 | |
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428 | my $cv = AnyEvent->condvar; |
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429 | |
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430 | my %result; |
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431 | $cv->begin (sub { $cv->send (\%result) }); |
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432 | |
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433 | for my $host (@list_of_hosts) { |
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434 | $cv->begin; |
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435 | ping_host_then_call_callback $host, sub { |
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436 | $result{$host} = ...; |
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437 | $cv->end; |
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438 | }; |
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439 | } |
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440 | |
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441 | $cv->end; |
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442 | |
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443 | This code fragment supposedly pings a number of hosts and calls |
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444 | C<send> after results for all then have have been gathered - in any |
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445 | order. To achieve this, the code issues a call to C<begin> when it starts |
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446 | each ping request and calls C<end> when it has received some result for |
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447 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
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448 | results arrive is not relevant. |
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449 | |
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450 | There is an additional bracketing call to C<begin> and C<end> outside the |
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451 | loop, which serves two important purposes: first, it sets the callback |
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452 | to be called once the counter reaches C<0>, and second, it ensures that |
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453 | C<send> is called even when C<no> hosts are being pinged (the loop |
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454 | doesn't execute once). |
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455 | |
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456 | This is the general pattern when you "fan out" into multiple subrequests: |
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457 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
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458 | is called at least once, and then, for each subrequest you start, call |
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459 | C<begin> and for each subrequest you finish, call C<end>. |
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460 | |
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461 | =back |
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462 | |
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463 | =head3 METHODS FOR CONSUMERS |
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464 | |
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465 | These methods should only be used by the consuming side, i.e. the |
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466 | code awaits the condition. |
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467 | |
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468 | =over 4 |
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469 | |
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470 | =item $cv->recv |
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471 | |
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472 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
332 | called on c<$cv>, while servicing other watchers normally. |
473 | >> methods have been called on c<$cv>, while servicing other watchers |
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474 | normally. |
333 | |
475 | |
334 | You can only wait once on a condition - additional calls will return |
476 | You can only wait once on a condition - additional calls are valid but |
335 | immediately. |
477 | will return immediately. |
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478 | |
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479 | If an error condition has been set by calling C<< ->croak >>, then this |
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480 | function will call C<croak>. |
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481 | |
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482 | In list context, all parameters passed to C<send> will be returned, |
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483 | in scalar context only the first one will be returned. |
336 | |
484 | |
337 | Not all event models support a blocking wait - some die in that case |
485 | Not all event models support a blocking wait - some die in that case |
338 | (programs might want to do that to stay interactive), so I<if you are |
486 | (programs might want to do that to stay interactive), so I<if you are |
339 | using this from a module, never require a blocking wait>, but let the |
487 | using this from a module, never require a blocking wait>, but let the |
340 | caller decide whether the call will block or not (for example, by coupling |
488 | caller decide whether the call will block or not (for example, by coupling |
341 | condition variables with some kind of request results and supporting |
489 | condition variables with some kind of request results and supporting |
342 | callbacks so the caller knows that getting the result will not block, |
490 | callbacks so the caller knows that getting the result will not block, |
343 | while still suppporting blocking waits if the caller so desires). |
491 | while still supporting blocking waits if the caller so desires). |
344 | |
492 | |
345 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
493 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
346 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
494 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
347 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
495 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
348 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
496 | can supply. |
349 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
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350 | from different coroutines, however). |
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351 | |
497 | |
352 | =item $cv->broadcast |
498 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
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499 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
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500 | versions and also integrates coroutines into AnyEvent, making blocking |
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501 | C<< ->recv >> calls perfectly safe as long as they are done from another |
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502 | coroutine (one that doesn't run the event loop). |
353 | |
503 | |
354 | Flag the condition as ready - a running C<< ->wait >> and all further |
504 | You can ensure that C<< -recv >> never blocks by setting a callback and |
355 | calls to C<wait> will (eventually) return after this method has been |
505 | only calling C<< ->recv >> from within that callback (or at a later |
356 | called. If nobody is waiting the broadcast will be remembered.. |
506 | time). This will work even when the event loop does not support blocking |
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507 | waits otherwise. |
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508 | |
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509 | =item $bool = $cv->ready |
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510 | |
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511 | Returns true when the condition is "true", i.e. whether C<send> or |
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512 | C<croak> have been called. |
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513 | |
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514 | =item $cb = $cv->cb ([new callback]) |
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515 | |
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516 | This is a mutator function that returns the callback set and optionally |
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517 | replaces it before doing so. |
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518 | |
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519 | The callback will be called when the condition becomes "true", i.e. when |
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520 | C<send> or C<croak> are called. Calling C<recv> inside the callback |
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521 | or at any later time is guaranteed not to block. |
357 | |
522 | |
358 | =back |
523 | =back |
359 | |
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360 | Example: |
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361 | |
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362 | # wait till the result is ready |
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363 | my $result_ready = AnyEvent->condvar; |
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364 | |
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365 | # do something such as adding a timer |
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366 | # or socket watcher the calls $result_ready->broadcast |
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367 | # when the "result" is ready. |
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368 | # in this case, we simply use a timer: |
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369 | my $w = AnyEvent->timer ( |
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370 | after => 1, |
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371 | cb => sub { $result_ready->broadcast }, |
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372 | ); |
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373 | |
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374 | # this "blocks" (while handling events) till the watcher |
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375 | # calls broadcast |
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376 | $result_ready->wait; |
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377 | |
524 | |
378 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
525 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
379 | |
526 | |
380 | =over 4 |
527 | =over 4 |
381 | |
528 | |
… | |
… | |
387 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
534 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
388 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
535 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
389 | |
536 | |
390 | The known classes so far are: |
537 | The known classes so far are: |
391 | |
538 | |
392 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
393 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
394 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
539 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
395 | AnyEvent::Impl::Event based on Event, second best choice. |
540 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
541 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
396 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
542 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
397 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
398 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
543 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
399 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
544 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
400 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
545 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
401 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
546 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
402 | |
547 | |
… | |
… | |
415 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
560 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
416 | if necessary. You should only call this function right before you would |
561 | if necessary. You should only call this function right before you would |
417 | have created an AnyEvent watcher anyway, that is, as late as possible at |
562 | have created an AnyEvent watcher anyway, that is, as late as possible at |
418 | runtime. |
563 | runtime. |
419 | |
564 | |
|
|
565 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
566 | |
|
|
567 | Arranges for the code block to be executed as soon as the event model is |
|
|
568 | autodetected (or immediately if this has already happened). |
|
|
569 | |
|
|
570 | If called in scalar or list context, then it creates and returns an object |
|
|
571 | that automatically removes the callback again when it is destroyed. See |
|
|
572 | L<Coro::BDB> for a case where this is useful. |
|
|
573 | |
|
|
574 | =item @AnyEvent::post_detect |
|
|
575 | |
|
|
576 | If there are any code references in this array (you can C<push> to it |
|
|
577 | before or after loading AnyEvent), then they will called directly after |
|
|
578 | the event loop has been chosen. |
|
|
579 | |
|
|
580 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
581 | if it contains a true value then the event loop has already been detected, |
|
|
582 | and the array will be ignored. |
|
|
583 | |
|
|
584 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
585 | |
420 | =back |
586 | =back |
421 | |
587 | |
422 | =head1 WHAT TO DO IN A MODULE |
588 | =head1 WHAT TO DO IN A MODULE |
423 | |
589 | |
424 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
590 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
427 | Be careful when you create watchers in the module body - AnyEvent will |
593 | Be careful when you create watchers in the module body - AnyEvent will |
428 | decide which event module to use as soon as the first method is called, so |
594 | decide which event module to use as soon as the first method is called, so |
429 | by calling AnyEvent in your module body you force the user of your module |
595 | by calling AnyEvent in your module body you force the user of your module |
430 | to load the event module first. |
596 | to load the event module first. |
431 | |
597 | |
432 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
598 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
433 | the C<< ->broadcast >> method has been called on it already. This is |
599 | the C<< ->send >> method has been called on it already. This is |
434 | because it will stall the whole program, and the whole point of using |
600 | because it will stall the whole program, and the whole point of using |
435 | events is to stay interactive. |
601 | events is to stay interactive. |
436 | |
602 | |
437 | It is fine, however, to call C<< ->wait >> when the user of your module |
603 | It is fine, however, to call C<< ->recv >> when the user of your module |
438 | requests it (i.e. if you create a http request object ad have a method |
604 | requests it (i.e. if you create a http request object ad have a method |
439 | called C<results> that returns the results, it should call C<< ->wait >> |
605 | called C<results> that returns the results, it should call C<< ->recv >> |
440 | freely, as the user of your module knows what she is doing. always). |
606 | freely, as the user of your module knows what she is doing. always). |
441 | |
607 | |
442 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
608 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
443 | |
609 | |
444 | There will always be a single main program - the only place that should |
610 | There will always be a single main program - the only place that should |
… | |
… | |
446 | |
612 | |
447 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
613 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
448 | do anything special (it does not need to be event-based) and let AnyEvent |
614 | do anything special (it does not need to be event-based) and let AnyEvent |
449 | decide which implementation to chose if some module relies on it. |
615 | decide which implementation to chose if some module relies on it. |
450 | |
616 | |
451 | If the main program relies on a specific event model. For example, in |
617 | If the main program relies on a specific event model - for example, in |
452 | Gtk2 programs you have to rely on the Glib module. You should load the |
618 | Gtk2 programs you have to rely on the Glib module - you should load the |
453 | event module before loading AnyEvent or any module that uses it: generally |
619 | event module before loading AnyEvent or any module that uses it: generally |
454 | speaking, you should load it as early as possible. The reason is that |
620 | speaking, you should load it as early as possible. The reason is that |
455 | modules might create watchers when they are loaded, and AnyEvent will |
621 | modules might create watchers when they are loaded, and AnyEvent will |
456 | decide on the event model to use as soon as it creates watchers, and it |
622 | decide on the event model to use as soon as it creates watchers, and it |
457 | might chose the wrong one unless you load the correct one yourself. |
623 | might chose the wrong one unless you load the correct one yourself. |
458 | |
624 | |
459 | You can chose to use a rather inefficient pure-perl implementation by |
625 | You can chose to use a pure-perl implementation by loading the |
460 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
626 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
461 | behaviour everywhere, but letting AnyEvent chose is generally better. |
627 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
628 | |
|
|
629 | =head2 MAINLOOP EMULATION |
|
|
630 | |
|
|
631 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
632 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
633 | |
|
|
634 | In that case, you can use a condition variable like this: |
|
|
635 | |
|
|
636 | AnyEvent->condvar->recv; |
|
|
637 | |
|
|
638 | This has the effect of entering the event loop and looping forever. |
|
|
639 | |
|
|
640 | Note that usually your program has some exit condition, in which case |
|
|
641 | it is better to use the "traditional" approach of storing a condition |
|
|
642 | variable somewhere, waiting for it, and sending it when the program should |
|
|
643 | exit cleanly. |
|
|
644 | |
|
|
645 | |
|
|
646 | =head1 OTHER MODULES |
|
|
647 | |
|
|
648 | The following is a non-exhaustive list of additional modules that use |
|
|
649 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
650 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
651 | available via CPAN. |
|
|
652 | |
|
|
653 | =over 4 |
|
|
654 | |
|
|
655 | =item L<AnyEvent::Util> |
|
|
656 | |
|
|
657 | Contains various utility functions that replace often-used but blocking |
|
|
658 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
659 | |
|
|
660 | =item L<AnyEvent::Handle> |
|
|
661 | |
|
|
662 | Provide read and write buffers and manages watchers for reads and writes. |
|
|
663 | |
|
|
664 | =item L<AnyEvent::Socket> |
|
|
665 | |
|
|
666 | Provides various utility functions for (internet protocol) sockets, |
|
|
667 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
668 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
669 | |
|
|
670 | =item L<AnyEvent::DNS> |
|
|
671 | |
|
|
672 | Provides rich asynchronous DNS resolver capabilities. |
|
|
673 | |
|
|
674 | =item L<AnyEvent::HTTPD> |
|
|
675 | |
|
|
676 | Provides a simple web application server framework. |
|
|
677 | |
|
|
678 | =item L<AnyEvent::FastPing> |
|
|
679 | |
|
|
680 | The fastest ping in the west. |
|
|
681 | |
|
|
682 | =item L<Net::IRC3> |
|
|
683 | |
|
|
684 | AnyEvent based IRC client module family. |
|
|
685 | |
|
|
686 | =item L<Net::XMPP2> |
|
|
687 | |
|
|
688 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
689 | |
|
|
690 | =item L<Net::FCP> |
|
|
691 | |
|
|
692 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
693 | of AnyEvent. |
|
|
694 | |
|
|
695 | =item L<Event::ExecFlow> |
|
|
696 | |
|
|
697 | High level API for event-based execution flow control. |
|
|
698 | |
|
|
699 | =item L<Coro> |
|
|
700 | |
|
|
701 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
702 | |
|
|
703 | =item L<AnyEvent::AIO>, L<IO::AIO> |
|
|
704 | |
|
|
705 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
706 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
707 | together. |
|
|
708 | |
|
|
709 | =item L<AnyEvent::BDB>, L<BDB> |
|
|
710 | |
|
|
711 | Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses |
|
|
712 | IO::AIO and AnyEvent together. |
|
|
713 | |
|
|
714 | =item L<IO::Lambda> |
|
|
715 | |
|
|
716 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
717 | |
|
|
718 | =back |
462 | |
719 | |
463 | =cut |
720 | =cut |
464 | |
721 | |
465 | package AnyEvent; |
722 | package AnyEvent; |
466 | |
723 | |
467 | no warnings; |
724 | no warnings; |
468 | use strict; |
725 | use strict; |
469 | |
726 | |
470 | use Carp; |
727 | use Carp; |
471 | |
728 | |
472 | our $VERSION = '3.3'; |
729 | our $VERSION = '4.03'; |
473 | our $MODEL; |
730 | our $MODEL; |
474 | |
731 | |
475 | our $AUTOLOAD; |
732 | our $AUTOLOAD; |
476 | our @ISA; |
733 | our @ISA; |
477 | |
734 | |
478 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
735 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
479 | |
736 | |
480 | our @REGISTRY; |
737 | our @REGISTRY; |
481 | |
738 | |
|
|
739 | our %PROTOCOL; # (ipv4|ipv6) => (1|2) |
|
|
740 | |
|
|
741 | { |
|
|
742 | my $idx; |
|
|
743 | $PROTOCOL{$_} = ++$idx |
|
|
744 | for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
745 | } |
|
|
746 | |
482 | my @models = ( |
747 | my @models = ( |
483 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
484 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
485 | [EV:: => AnyEvent::Impl::EV::], |
748 | [EV:: => AnyEvent::Impl::EV::], |
486 | [Event:: => AnyEvent::Impl::Event::], |
749 | [Event:: => AnyEvent::Impl::Event::], |
487 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
488 | [Tk:: => AnyEvent::Impl::Tk::], |
750 | [Tk:: => AnyEvent::Impl::Tk::], |
489 | [Wx:: => AnyEvent::Impl::POE::], |
751 | [Wx:: => AnyEvent::Impl::POE::], |
490 | [Prima:: => AnyEvent::Impl::POE::], |
752 | [Prima:: => AnyEvent::Impl::POE::], |
491 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
753 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
492 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
754 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
|
|
755 | [Glib:: => AnyEvent::Impl::Glib::], |
493 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
756 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
494 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
757 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
495 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
758 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
496 | ); |
759 | ); |
497 | |
760 | |
498 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
761 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
|
|
762 | |
|
|
763 | our @post_detect; |
|
|
764 | |
|
|
765 | sub post_detect(&) { |
|
|
766 | my ($cb) = @_; |
|
|
767 | |
|
|
768 | if ($MODEL) { |
|
|
769 | $cb->(); |
|
|
770 | |
|
|
771 | 1 |
|
|
772 | } else { |
|
|
773 | push @post_detect, $cb; |
|
|
774 | |
|
|
775 | defined wantarray |
|
|
776 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
777 | : () |
|
|
778 | } |
|
|
779 | } |
|
|
780 | |
|
|
781 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
782 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
783 | } |
499 | |
784 | |
500 | sub detect() { |
785 | sub detect() { |
501 | unless ($MODEL) { |
786 | unless ($MODEL) { |
502 | no strict 'refs'; |
787 | no strict 'refs'; |
503 | |
788 | |
… | |
… | |
537 | last; |
822 | last; |
538 | } |
823 | } |
539 | } |
824 | } |
540 | |
825 | |
541 | $MODEL |
826 | $MODEL |
542 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
827 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
543 | } |
828 | } |
544 | } |
829 | } |
545 | |
830 | |
546 | unshift @ISA, $MODEL; |
831 | unshift @ISA, $MODEL; |
547 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
832 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
833 | |
|
|
834 | (shift @post_detect)->() while @post_detect; |
548 | } |
835 | } |
549 | |
836 | |
550 | $MODEL |
837 | $MODEL |
551 | } |
838 | } |
552 | |
839 | |
… | |
… | |
562 | $class->$func (@_); |
849 | $class->$func (@_); |
563 | } |
850 | } |
564 | |
851 | |
565 | package AnyEvent::Base; |
852 | package AnyEvent::Base; |
566 | |
853 | |
567 | # default implementation for ->condvar, ->wait, ->broadcast |
854 | # default implementation for ->condvar |
568 | |
855 | |
569 | sub condvar { |
856 | sub condvar { |
570 | bless \my $flag, "AnyEvent::Base::CondVar" |
857 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
571 | } |
|
|
572 | |
|
|
573 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
574 | ${$_[0]}++; |
|
|
575 | } |
|
|
576 | |
|
|
577 | sub AnyEvent::Base::CondVar::wait { |
|
|
578 | AnyEvent->one_event while !${$_[0]}; |
|
|
579 | } |
858 | } |
580 | |
859 | |
581 | # default implementation for ->signal |
860 | # default implementation for ->signal |
582 | |
861 | |
583 | our %SIG_CB; |
862 | our %SIG_CB; |
… | |
… | |
657 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
936 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
658 | |
937 | |
659 | undef $CHLD_W unless keys %PID_CB; |
938 | undef $CHLD_W unless keys %PID_CB; |
660 | } |
939 | } |
661 | |
940 | |
|
|
941 | package AnyEvent::CondVar; |
|
|
942 | |
|
|
943 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
944 | |
|
|
945 | package AnyEvent::CondVar::Base; |
|
|
946 | |
|
|
947 | use overload |
|
|
948 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
949 | fallback => 1; |
|
|
950 | |
|
|
951 | sub _send { |
|
|
952 | # nop |
|
|
953 | } |
|
|
954 | |
|
|
955 | sub send { |
|
|
956 | my $cv = shift; |
|
|
957 | $cv->{_ae_sent} = [@_]; |
|
|
958 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
959 | $cv->_send; |
|
|
960 | } |
|
|
961 | |
|
|
962 | sub croak { |
|
|
963 | $_[0]{_ae_croak} = $_[1]; |
|
|
964 | $_[0]->send; |
|
|
965 | } |
|
|
966 | |
|
|
967 | sub ready { |
|
|
968 | $_[0]{_ae_sent} |
|
|
969 | } |
|
|
970 | |
|
|
971 | sub _wait { |
|
|
972 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
973 | } |
|
|
974 | |
|
|
975 | sub recv { |
|
|
976 | $_[0]->_wait; |
|
|
977 | |
|
|
978 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
979 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
980 | } |
|
|
981 | |
|
|
982 | sub cb { |
|
|
983 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
984 | $_[0]{_ae_cb} |
|
|
985 | } |
|
|
986 | |
|
|
987 | sub begin { |
|
|
988 | ++$_[0]{_ae_counter}; |
|
|
989 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
990 | } |
|
|
991 | |
|
|
992 | sub end { |
|
|
993 | return if --$_[0]{_ae_counter}; |
|
|
994 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
995 | } |
|
|
996 | |
|
|
997 | # undocumented/compatibility with pre-3.4 |
|
|
998 | *broadcast = \&send; |
|
|
999 | *wait = \&_wait; |
|
|
1000 | |
662 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1001 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
663 | |
1002 | |
664 | This is an advanced topic that you do not normally need to use AnyEvent in |
1003 | This is an advanced topic that you do not normally need to use AnyEvent in |
665 | a module. This section is only of use to event loop authors who want to |
1004 | a module. This section is only of use to event loop authors who want to |
666 | provide AnyEvent compatibility. |
1005 | provide AnyEvent compatibility. |
… | |
… | |
722 | model it chooses. |
1061 | model it chooses. |
723 | |
1062 | |
724 | =item C<PERL_ANYEVENT_MODEL> |
1063 | =item C<PERL_ANYEVENT_MODEL> |
725 | |
1064 | |
726 | This can be used to specify the event model to be used by AnyEvent, before |
1065 | This can be used to specify the event model to be used by AnyEvent, before |
727 | autodetection and -probing kicks in. It must be a string consisting |
1066 | auto detection and -probing kicks in. It must be a string consisting |
728 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1067 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
729 | and the resulting module name is loaded and if the load was successful, |
1068 | and the resulting module name is loaded and if the load was successful, |
730 | used as event model. If it fails to load AnyEvent will proceed with |
1069 | used as event model. If it fails to load AnyEvent will proceed with |
731 | autodetection and -probing. |
1070 | auto detection and -probing. |
732 | |
1071 | |
733 | This functionality might change in future versions. |
1072 | This functionality might change in future versions. |
734 | |
1073 | |
735 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1074 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
736 | could start your program like this: |
1075 | could start your program like this: |
737 | |
1076 | |
738 | PERL_ANYEVENT_MODEL=Perl perl ... |
1077 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1078 | |
|
|
1079 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1080 | |
|
|
1081 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1082 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1083 | of auto probing). |
|
|
1084 | |
|
|
1085 | Must be set to a comma-separated list of protocols or address families, |
|
|
1086 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1087 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1088 | list. |
|
|
1089 | |
|
|
1090 | This variable can effectively be used for denial-of-service attacks |
|
|
1091 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1092 | small, as the program has to handle connection errors already- |
|
|
1093 | |
|
|
1094 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1095 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1096 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1097 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1098 | IPv6, but prefer IPv6 over IPv4. |
|
|
1099 | |
|
|
1100 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1101 | |
|
|
1102 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1103 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1104 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1105 | default. |
|
|
1106 | |
|
|
1107 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1108 | EDNS0 in its DNS requests. |
739 | |
1109 | |
740 | =back |
1110 | =back |
741 | |
1111 | |
742 | =head1 EXAMPLE PROGRAM |
1112 | =head1 EXAMPLE PROGRAM |
743 | |
1113 | |
… | |
… | |
754 | poll => 'r', |
1124 | poll => 'r', |
755 | cb => sub { |
1125 | cb => sub { |
756 | warn "io event <$_[0]>\n"; # will always output <r> |
1126 | warn "io event <$_[0]>\n"; # will always output <r> |
757 | chomp (my $input = <STDIN>); # read a line |
1127 | chomp (my $input = <STDIN>); # read a line |
758 | warn "read: $input\n"; # output what has been read |
1128 | warn "read: $input\n"; # output what has been read |
759 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1129 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
760 | }, |
1130 | }, |
761 | ); |
1131 | ); |
762 | |
1132 | |
763 | my $time_watcher; # can only be used once |
1133 | my $time_watcher; # can only be used once |
764 | |
1134 | |
… | |
… | |
769 | }); |
1139 | }); |
770 | } |
1140 | } |
771 | |
1141 | |
772 | new_timer; # create first timer |
1142 | new_timer; # create first timer |
773 | |
1143 | |
774 | $cv->wait; # wait until user enters /^q/i |
1144 | $cv->recv; # wait until user enters /^q/i |
775 | |
1145 | |
776 | =head1 REAL-WORLD EXAMPLE |
1146 | =head1 REAL-WORLD EXAMPLE |
777 | |
1147 | |
778 | Consider the L<Net::FCP> module. It features (among others) the following |
1148 | Consider the L<Net::FCP> module. It features (among others) the following |
779 | API calls, which are to freenet what HTTP GET requests are to http: |
1149 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
829 | syswrite $txn->{fh}, $txn->{request} |
1199 | syswrite $txn->{fh}, $txn->{request} |
830 | or die "connection or write error"; |
1200 | or die "connection or write error"; |
831 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1201 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
832 | |
1202 | |
833 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1203 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
834 | result and signals any possible waiters that the request ahs finished: |
1204 | result and signals any possible waiters that the request has finished: |
835 | |
1205 | |
836 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1206 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
837 | |
1207 | |
838 | if (end-of-file or data complete) { |
1208 | if (end-of-file or data complete) { |
839 | $txn->{result} = $txn->{buf}; |
1209 | $txn->{result} = $txn->{buf}; |
840 | $txn->{finished}->broadcast; |
1210 | $txn->{finished}->send; |
841 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1211 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
842 | } |
1212 | } |
843 | |
1213 | |
844 | The C<result> method, finally, just waits for the finished signal (if the |
1214 | The C<result> method, finally, just waits for the finished signal (if the |
845 | request was already finished, it doesn't wait, of course, and returns the |
1215 | request was already finished, it doesn't wait, of course, and returns the |
846 | data: |
1216 | data: |
847 | |
1217 | |
848 | $txn->{finished}->wait; |
1218 | $txn->{finished}->recv; |
849 | return $txn->{result}; |
1219 | return $txn->{result}; |
850 | |
1220 | |
851 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1221 | The actual code goes further and collects all errors (C<die>s, exceptions) |
852 | that occured during request processing. The C<result> method detects |
1222 | that occurred during request processing. The C<result> method detects |
853 | whether an exception as thrown (it is stored inside the $txn object) |
1223 | whether an exception as thrown (it is stored inside the $txn object) |
854 | and just throws the exception, which means connection errors and other |
1224 | and just throws the exception, which means connection errors and other |
855 | problems get reported tot he code that tries to use the result, not in a |
1225 | problems get reported tot he code that tries to use the result, not in a |
856 | random callback. |
1226 | random callback. |
857 | |
1227 | |
… | |
… | |
888 | |
1258 | |
889 | my $quit = AnyEvent->condvar; |
1259 | my $quit = AnyEvent->condvar; |
890 | |
1260 | |
891 | $fcp->txn_client_get ($url)->cb (sub { |
1261 | $fcp->txn_client_get ($url)->cb (sub { |
892 | ... |
1262 | ... |
893 | $quit->broadcast; |
1263 | $quit->send; |
894 | }); |
1264 | }); |
895 | |
1265 | |
896 | $quit->wait; |
1266 | $quit->recv; |
897 | |
1267 | |
898 | |
1268 | |
899 | =head1 BENCHMARKS |
1269 | =head1 BENCHMARKS |
900 | |
1270 | |
901 | To give you an idea of the performance and overheads that AnyEvent adds |
1271 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
903 | of various event loops I prepared some benchmarks. |
1273 | of various event loops I prepared some benchmarks. |
904 | |
1274 | |
905 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1275 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
906 | |
1276 | |
907 | Here is a benchmark of various supported event models used natively and |
1277 | Here is a benchmark of various supported event models used natively and |
908 | through anyevent. The benchmark creates a lot of timers (with a zero |
1278 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
909 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1279 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
910 | which it is), lets them fire exactly once and destroys them again. |
1280 | which it is), lets them fire exactly once and destroys them again. |
911 | |
1281 | |
912 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1282 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
913 | distribution. |
1283 | distribution. |
… | |
… | |
930 | all watchers, to avoid adding memory overhead. That means closure creation |
1300 | all watchers, to avoid adding memory overhead. That means closure creation |
931 | and memory usage is not included in the figures. |
1301 | and memory usage is not included in the figures. |
932 | |
1302 | |
933 | I<invoke> is the time, in microseconds, used to invoke a simple |
1303 | I<invoke> is the time, in microseconds, used to invoke a simple |
934 | callback. The callback simply counts down a Perl variable and after it was |
1304 | callback. The callback simply counts down a Perl variable and after it was |
935 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1305 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
936 | signal the end of this phase. |
1306 | signal the end of this phase. |
937 | |
1307 | |
938 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1308 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
939 | watcher. |
1309 | watcher. |
940 | |
1310 | |
… | |
… | |
944 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1314 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
945 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
1315 | EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers |
946 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
1316 | CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal |
947 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
1317 | Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation |
948 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
1318 | Event/Event 16000 516 31.88 31.30 0.85 Event native interface |
949 | Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers |
1319 | Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers |
950 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
1320 | Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour |
951 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
1321 | Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers |
952 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
1322 | POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event |
953 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
1323 | POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select |
954 | |
1324 | |
… | |
… | |
963 | |
1333 | |
964 | Also, note that the number of watchers usually has a nonlinear effect on |
1334 | Also, note that the number of watchers usually has a nonlinear effect on |
965 | overall speed, that is, creating twice as many watchers doesn't take twice |
1335 | overall speed, that is, creating twice as many watchers doesn't take twice |
966 | the time - usually it takes longer. This puts event loops tested with a |
1336 | the time - usually it takes longer. This puts event loops tested with a |
967 | higher number of watchers at a disadvantage. |
1337 | higher number of watchers at a disadvantage. |
|
|
1338 | |
|
|
1339 | To put the range of results into perspective, consider that on the |
|
|
1340 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
|
|
1341 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
|
|
1342 | cycles with POE. |
968 | |
1343 | |
969 | C<EV> is the sole leader regarding speed and memory use, which are both |
1344 | C<EV> is the sole leader regarding speed and memory use, which are both |
970 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
1345 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
971 | far less memory than any other event loop and is still faster than Event |
1346 | far less memory than any other event loop and is still faster than Event |
972 | natively. |
1347 | natively. |
… | |
… | |
995 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1370 | file descriptor is dup()ed for each watcher. This shows that the dup() |
996 | employed by some adaptors is not a big performance issue (it does incur a |
1371 | employed by some adaptors is not a big performance issue (it does incur a |
997 | hidden memory cost inside the kernel which is not reflected in the figures |
1372 | hidden memory cost inside the kernel which is not reflected in the figures |
998 | above). |
1373 | above). |
999 | |
1374 | |
1000 | C<POE>, regardless of underlying event loop (whether using its pure |
1375 | C<POE>, regardless of underlying event loop (whether using its pure perl |
1001 | perl select-based backend or the Event module, the POE-EV backend |
1376 | select-based backend or the Event module, the POE-EV backend couldn't |
1002 | couldn't be tested because it wasn't working) shows abysmal performance |
1377 | be tested because it wasn't working) shows abysmal performance and |
1003 | and memory usage: Watchers use almost 30 times as much memory as |
1378 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
1004 | EV watchers, and 10 times as much memory as Event (the high memory |
1379 | as EV watchers, and 10 times as much memory as Event (the high memory |
1005 | requirements are caused by requiring a session for each watcher). Watcher |
1380 | requirements are caused by requiring a session for each watcher). Watcher |
1006 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
1381 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1382 | implementation. |
|
|
1383 | |
1007 | implementation. The design of the POE adaptor class in AnyEvent can not |
1384 | The design of the POE adaptor class in AnyEvent can not really account |
1008 | really account for this, as session creation overhead is small compared |
1385 | for the performance issues, though, as session creation overhead is |
1009 | to execution of the state machine, which is coded pretty optimally within |
1386 | small compared to execution of the state machine, which is coded pretty |
1010 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1387 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1388 | using multiple sessions is not a good approach, especially regarding |
|
|
1389 | memory usage, even the author of POE could not come up with a faster |
|
|
1390 | design). |
1011 | |
1391 | |
1012 | =head3 Summary |
1392 | =head3 Summary |
1013 | |
1393 | |
1014 | =over 4 |
1394 | =over 4 |
1015 | |
1395 | |
… | |
… | |
1026 | |
1406 | |
1027 | =back |
1407 | =back |
1028 | |
1408 | |
1029 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1409 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1030 | |
1410 | |
1031 | This benchmark atcually benchmarks the event loop itself. It works by |
1411 | This benchmark actually benchmarks the event loop itself. It works by |
1032 | creating a number of "servers": each server consists of a socketpair, a |
1412 | creating a number of "servers": each server consists of a socket pair, a |
1033 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1413 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1034 | watcher waiting for input on one side of the socket. Each time the socket |
1414 | watcher waiting for input on one side of the socket. Each time the socket |
1035 | watcher reads a byte it will write that byte to a random other "server". |
1415 | watcher reads a byte it will write that byte to a random other "server". |
1036 | |
1416 | |
1037 | The effect is that there will be a lot of I/O watchers, only part of which |
1417 | The effect is that there will be a lot of I/O watchers, only part of which |
1038 | are active at any one point (so there is a constant number of active |
1418 | are active at any one point (so there is a constant number of active |
1039 | fds for each loop iterstaion, but which fds these are is random). The |
1419 | fds for each loop iteration, but which fds these are is random). The |
1040 | timeout is reset each time something is read because that reflects how |
1420 | timeout is reset each time something is read because that reflects how |
1041 | most timeouts work (and puts extra pressure on the event loops). |
1421 | most timeouts work (and puts extra pressure on the event loops). |
1042 | |
1422 | |
1043 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1423 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1044 | (1%) are active. This mirrors the activity of large servers with many |
1424 | (1%) are active. This mirrors the activity of large servers with many |
1045 | connections, most of which are idle at any one point in time. |
1425 | connections, most of which are idle at any one point in time. |
1046 | |
1426 | |
1047 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1427 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1048 | distribution. |
1428 | distribution. |
… | |
… | |
1050 | =head3 Explanation of the columns |
1430 | =head3 Explanation of the columns |
1051 | |
1431 | |
1052 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1432 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1053 | each server has a read and write socket end). |
1433 | each server has a read and write socket end). |
1054 | |
1434 | |
1055 | I<create> is the time it takes to create a socketpair (which is |
1435 | I<create> is the time it takes to create a socket pair (which is |
1056 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1436 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1057 | |
1437 | |
1058 | I<request>, the most important value, is the time it takes to handle a |
1438 | I<request>, the most important value, is the time it takes to handle a |
1059 | single "request", that is, reading the token from the pipe and forwarding |
1439 | single "request", that is, reading the token from the pipe and forwarding |
1060 | it to another server. This includes deleting the old timeout and creating |
1440 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1062 | |
1442 | |
1063 | =head3 Results |
1443 | =head3 Results |
1064 | |
1444 | |
1065 | name sockets create request |
1445 | name sockets create request |
1066 | EV 20000 69.01 11.16 |
1446 | EV 20000 69.01 11.16 |
1067 | Perl 20000 75.28 112.76 |
1447 | Perl 20000 73.32 35.87 |
1068 | Event 20000 212.62 257.32 |
1448 | Event 20000 212.62 257.32 |
1069 | Glib 20000 651.16 1896.30 |
1449 | Glib 20000 651.16 1896.30 |
1070 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1450 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1071 | |
1451 | |
1072 | =head3 Discussion |
1452 | =head3 Discussion |
… | |
… | |
1094 | |
1474 | |
1095 | =head3 Summary |
1475 | =head3 Summary |
1096 | |
1476 | |
1097 | =over 4 |
1477 | =over 4 |
1098 | |
1478 | |
1099 | =item * The pure perl implementation performs extremely well, considering |
1479 | =item * The pure perl implementation performs extremely well. |
1100 | that it uses select. |
|
|
1101 | |
1480 | |
1102 | =item * Avoid Glib or POE in large projects where performance matters. |
1481 | =item * Avoid Glib or POE in large projects where performance matters. |
1103 | |
1482 | |
1104 | =back |
1483 | =back |
1105 | |
1484 | |
… | |
… | |
1118 | |
1497 | |
1119 | =head3 Results |
1498 | =head3 Results |
1120 | |
1499 | |
1121 | name sockets create request |
1500 | name sockets create request |
1122 | EV 16 20.00 6.54 |
1501 | EV 16 20.00 6.54 |
|
|
1502 | Perl 16 25.75 12.62 |
1123 | Event 16 81.27 35.86 |
1503 | Event 16 81.27 35.86 |
1124 | Glib 16 32.63 15.48 |
1504 | Glib 16 32.63 15.48 |
1125 | Perl 16 24.62 162.37 |
|
|
1126 | POE 16 261.87 276.28 uses POE::Loop::Event |
1505 | POE 16 261.87 276.28 uses POE::Loop::Event |
1127 | |
1506 | |
1128 | =head3 Discussion |
1507 | =head3 Discussion |
1129 | |
1508 | |
1130 | The benchmark tries to test the performance of a typical small |
1509 | The benchmark tries to test the performance of a typical small |
1131 | server. While knowing how various event loops perform is interesting, keep |
1510 | server. While knowing how various event loops perform is interesting, keep |
1132 | in mind that their overhead in this case is usually not as important, due |
1511 | in mind that their overhead in this case is usually not as important, due |
1133 | to the small absolute number of watchers. |
1512 | to the small absolute number of watchers (that is, you need efficiency and |
|
|
1513 | speed most when you have lots of watchers, not when you only have a few of |
|
|
1514 | them). |
1134 | |
1515 | |
1135 | EV is again fastest. |
1516 | EV is again fastest. |
1136 | |
1517 | |
1137 | The C-based event loops Event and Glib come in second this time, as the |
1518 | Perl again comes second. It is noticeably faster than the C-based event |
1138 | overhead of running an iteration is much smaller in C than in Perl (little |
1519 | loops Event and Glib, although the difference is too small to really |
1139 | code to execute in the inner loop, and perl's function calling overhead is |
1520 | matter. |
1140 | high, and updating all the data structures is costly). |
|
|
1141 | |
1521 | |
1142 | The pure perl event loop is much slower, but still competitive. |
|
|
1143 | |
|
|
1144 | POE also performs much better in this case, but is is stillf ar behind the |
1522 | POE also performs much better in this case, but is is still far behind the |
1145 | others. |
1523 | others. |
1146 | |
1524 | |
1147 | =head3 Summary |
1525 | =head3 Summary |
1148 | |
1526 | |
1149 | =over 4 |
1527 | =over 4 |
… | |
… | |
1155 | |
1533 | |
1156 | |
1534 | |
1157 | =head1 FORK |
1535 | =head1 FORK |
1158 | |
1536 | |
1159 | Most event libraries are not fork-safe. The ones who are usually are |
1537 | Most event libraries are not fork-safe. The ones who are usually are |
1160 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1538 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1539 | calls. Only L<EV> is fully fork-aware. |
1161 | |
1540 | |
1162 | If you have to fork, you must either do so I<before> creating your first |
1541 | If you have to fork, you must either do so I<before> creating your first |
1163 | watcher OR you must not use AnyEvent at all in the child. |
1542 | watcher OR you must not use AnyEvent at all in the child. |
1164 | |
1543 | |
1165 | |
1544 | |
… | |
… | |
1177 | |
1556 | |
1178 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1557 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1179 | |
1558 | |
1180 | use AnyEvent; |
1559 | use AnyEvent; |
1181 | |
1560 | |
|
|
1561 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1562 | be used to probe what backend is used and gain other information (which is |
|
|
1563 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
|
|
1564 | |
1182 | |
1565 | |
1183 | =head1 SEE ALSO |
1566 | =head1 SEE ALSO |
1184 | |
1567 | |
1185 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1568 | Utility functions: L<AnyEvent::Util>. |
1186 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1569 | |
|
|
1570 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1187 | L<Event::Lib>, L<Qt>, L<POE>. |
1571 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1188 | |
1572 | |
1189 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1573 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1190 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1574 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1191 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1575 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1192 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1576 | L<AnyEvent::Impl::POE>. |
1193 | |
1577 | |
|
|
1578 | Non-blocking file handles, sockets, TCP clients and |
|
|
1579 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1580 | |
|
|
1581 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1582 | |
|
|
1583 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1584 | |
1194 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1585 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1195 | |
1586 | |
1196 | |
1587 | |
1197 | =head1 AUTHOR |
1588 | =head1 AUTHOR |
1198 | |
1589 | |
1199 | Marc Lehmann <schmorp@schmorp.de> |
1590 | Marc Lehmann <schmorp@schmorp.de> |