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 and POE are various supported |
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6 | event loops. |
6 | |
7 | |
7 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
8 | |
9 | |
9 | use AnyEvent; |
10 | use AnyEvent; |
10 | |
11 | |
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12 | # file descriptor readable |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
13 | my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); |
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14 | |
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15 | # one-shot or repeating timers |
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16 | my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); |
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17 | my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... |
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18 | |
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19 | print AnyEvent->now; # prints current event loop time |
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20 | print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. |
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21 | |
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22 | # POSIX signal |
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23 | my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); |
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24 | |
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25 | # child process exit |
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26 | my $w = AnyEvent->child (pid => $pid, cb => sub { |
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27 | my ($pid, $status) = @_; |
12 | ... |
28 | ... |
13 | }); |
29 | }); |
14 | |
30 | |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
31 | # called when event loop idle (if applicable) |
16 | ... |
32 | my $w = AnyEvent->idle (cb => sub { ... }); |
17 | }); |
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18 | |
33 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
34 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
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35 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
36 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
37 | # use a condvar in callback mode: |
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38 | $w->cb (sub { $_[0]->recv }); |
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39 | |
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40 | =head1 INTRODUCTION/TUTORIAL |
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41 | |
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42 | This manpage is mainly a reference manual. If you are interested |
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43 | in a tutorial or some gentle introduction, have a look at the |
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44 | L<AnyEvent::Intro> manpage. |
22 | |
45 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
46 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
47 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
48 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
49 | nowadays. So what is different about AnyEvent? |
27 | |
50 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
51 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
29 | policy> and AnyEvent is I<small and efficient>. |
52 | policy> and AnyEvent is I<small and efficient>. |
30 | |
53 | |
31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
54 | First and foremost, I<AnyEvent is not an event model> itself, it only |
32 | interfaces to whatever event model the main program happens to use in a |
55 | interfaces to whatever event model the main program happens to use, in a |
33 | pragmatic way. For event models and certain classes of immortals alike, |
56 | pragmatic way. For event models and certain classes of immortals alike, |
34 | the statement "there can only be one" is a bitter reality: In general, |
57 | the statement "there can only be one" is a bitter reality: In general, |
35 | only one event loop can be active at the same time in a process. AnyEvent |
58 | only one event loop can be active at the same time in a process. AnyEvent |
36 | helps hiding the differences between those event loops. |
59 | cannot change this, but it can hide the differences between those event |
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60 | loops. |
37 | |
61 | |
38 | The goal of AnyEvent is to offer module authors the ability to do event |
62 | The goal of AnyEvent is to offer module authors the ability to do event |
39 | programming (waiting for I/O or timer events) without subscribing to a |
63 | programming (waiting for I/O or timer events) without subscribing to a |
40 | religion, a way of living, and most importantly: without forcing your |
64 | religion, a way of living, and most importantly: without forcing your |
41 | module users into the same thing by forcing them to use the same event |
65 | module users into the same thing by forcing them to use the same event |
42 | model you use. |
66 | model you use. |
43 | |
67 | |
44 | For modules like POE or IO::Async (which is a total misnomer as it is |
68 | For modules like POE or IO::Async (which is a total misnomer as it is |
45 | actually doing all I/O I<synchronously>...), using them in your module is |
69 | actually doing all I/O I<synchronously>...), using them in your module is |
46 | like joining a cult: After you joined, you are dependent on them and you |
70 | like joining a cult: After you joined, you are dependent on them and you |
47 | cannot use anything else, as it is simply incompatible to everything that |
71 | cannot use anything else, as they are simply incompatible to everything |
48 | isn't itself. What's worse, all the potential users of your module are |
72 | that isn't them. What's worse, all the potential users of your |
49 | I<also> forced to use the same event loop you use. |
73 | module are I<also> forced to use the same event loop you use. |
50 | |
74 | |
51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
75 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
76 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
77 | with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if |
54 | your module uses one of those, every user of your module has to use it, |
78 | your module uses one of those, every user of your module has to use it, |
55 | too. But if your module uses AnyEvent, it works transparently with all |
79 | too. But if your module uses AnyEvent, it works transparently with all |
56 | event models it supports (including stuff like POE and IO::Async, as long |
80 | event models it supports (including stuff like IO::Async, as long as those |
57 | as those use one of the supported event loops. It is trivial to add new |
81 | use one of the supported event loops. It is trivial to add new event loops |
58 | event loops to AnyEvent, too, so it is future-proof). |
82 | to AnyEvent, too, so it is future-proof). |
59 | |
83 | |
60 | In addition to being free of having to use I<the one and only true event |
84 | 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 |
85 | 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 |
86 | 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 |
87 | 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 |
88 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
89 | technically possible. |
66 | |
90 | |
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91 | Of course, AnyEvent comes with a big (and fully optional!) toolbox |
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92 | of useful functionality, such as an asynchronous DNS resolver, 100% |
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93 | non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms |
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94 | such as Windows) and lots of real-world knowledge and workarounds for |
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95 | platform bugs and differences. |
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96 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
97 | Now, if you I<do 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 |
98 | useful) and you want to force your users to use the one and only event |
69 | model, you should I<not> use this module. |
99 | model, you should I<not> use this module. |
70 | |
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71 | |
100 | |
72 | =head1 DESCRIPTION |
101 | =head1 DESCRIPTION |
73 | |
102 | |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
103 | L<AnyEvent> provides an identical interface to multiple event loops. This |
75 | allows module authors to utilise an event loop without forcing module |
104 | allows module authors to utilise an event loop without forcing module |
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79 | The interface itself is vaguely similar, but not identical to the L<Event> |
108 | The interface itself is vaguely similar, but not identical to the L<Event> |
80 | module. |
109 | module. |
81 | |
110 | |
82 | During the first call of any watcher-creation method, the module tries |
111 | 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 |
112 | 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>, |
113 | following modules is already loaded: L<EV>, |
85 | L<Event>, L<Glib>, L<Tk>, L<AnyEvent::Impl::Perl>, L<Event::Lib>, L<Qt>, |
114 | 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 |
115 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Event::Lib, Qt and POE as the pure perl |
116 | 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 |
117 | 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 |
118 | be successfully loaded will be used. If, after this, still none could be |
90 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
119 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
91 | very efficient, but should work everywhere. |
120 | very efficient, but should work everywhere. |
92 | |
121 | |
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103 | starts using it, all bets are off. Maybe you should tell their authors to |
132 | starts using it, all bets are off. Maybe you should tell their authors to |
104 | use AnyEvent so their modules work together with others seamlessly... |
133 | use AnyEvent so their modules work together with others seamlessly... |
105 | |
134 | |
106 | The pure-perl implementation of AnyEvent is called |
135 | The pure-perl implementation of AnyEvent is called |
107 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
136 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
108 | explicitly. |
137 | explicitly and enjoy the high availability of that event loop :) |
109 | |
138 | |
110 | =head1 WATCHERS |
139 | =head1 WATCHERS |
111 | |
140 | |
112 | AnyEvent has the central concept of a I<watcher>, which is an object that |
141 | 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 |
142 | stores relevant data for each kind of event you are waiting for, such as |
114 | the callback to call, the filehandle to watch, etc. |
143 | the callback to call, the file handle to watch, etc. |
115 | |
144 | |
116 | These watchers are normal Perl objects with normal Perl lifetime. After |
145 | These watchers are normal Perl objects with normal Perl lifetime. After |
117 | creating a watcher it will immediately "watch" for events and invoke the |
146 | 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 |
147 | callback when the event occurs (of course, only when the event model |
119 | is in control). |
148 | is in control). |
120 | |
149 | |
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150 | Note that B<callbacks must not permanently change global variables> |
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151 | potentially in use by the event loop (such as C<$_> or C<$[>) and that B<< |
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152 | callbacks must not C<die> >>. The former is good programming practise in |
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153 | Perl and the latter stems from the fact that exception handling differs |
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154 | widely between event loops. |
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155 | |
121 | To disable the watcher you have to destroy it (e.g. by setting the |
156 | To disable the watcher you have to destroy it (e.g. by setting the |
122 | variable you store it in to C<undef> or otherwise deleting all references |
157 | variable you store it in to C<undef> or otherwise deleting all references |
123 | to it). |
158 | to it). |
124 | |
159 | |
125 | All watchers are created by calling a method on the C<AnyEvent> class. |
160 | All watchers are created by calling a method on the C<AnyEvent> class. |
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127 | Many watchers either are used with "recursion" (repeating timers for |
162 | Many watchers either are used with "recursion" (repeating timers for |
128 | example), or need to refer to their watcher object in other ways. |
163 | example), or need to refer to their watcher object in other ways. |
129 | |
164 | |
130 | An any way to achieve that is this pattern: |
165 | An any way to achieve that is this pattern: |
131 | |
166 | |
132 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
167 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
133 | # you can use $w here, for example to undef it |
168 | # you can use $w here, for example to undef it |
134 | undef $w; |
169 | undef $w; |
135 | }); |
170 | }); |
136 | |
171 | |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
172 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
138 | my variables are only visible after the statement in which they are |
173 | my variables are only visible after the statement in which they are |
139 | declared. |
174 | declared. |
140 | |
175 | |
141 | =head2 IO WATCHERS |
176 | =head2 I/O WATCHERS |
142 | |
177 | |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
178 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
144 | with the following mandatory key-value pairs as arguments: |
179 | with the following mandatory key-value pairs as arguments: |
145 | |
180 | |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
181 | C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch |
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182 | for events (AnyEvent might or might not keep a reference to this file |
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183 | handle). Note that only file handles pointing to things for which |
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184 | non-blocking operation makes sense are allowed. This includes sockets, |
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185 | most character devices, pipes, fifos and so on, but not for example files |
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186 | or block devices. |
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187 | |
147 | events. C<poll> must be a string that is either C<r> or C<w>, which |
188 | C<poll> must be a string that is either C<r> or C<w>, which creates a |
148 | creates a watcher waiting for "r"eadable or "w"ritable events, |
189 | watcher waiting for "r"eadable or "w"ritable events, respectively. |
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190 | |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
191 | C<cb> is the callback to invoke each time the file handle becomes ready. |
150 | becomes ready. |
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151 | |
192 | |
152 | As long as the I/O watcher exists it will keep the file descriptor or a |
193 | Although the callback might get passed parameters, their value and |
153 | copy of it alive/open. |
194 | presence is undefined and you cannot rely on them. Portable AnyEvent |
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195 | callbacks cannot use arguments passed to I/O watcher callbacks. |
154 | |
196 | |
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197 | The I/O watcher might use the underlying file descriptor or a copy of it. |
155 | It is not allowed to close a file handle as long as any watcher is active |
198 | You must not close a file handle as long as any watcher is active on the |
156 | on the underlying file descriptor. |
199 | underlying file descriptor. |
157 | |
200 | |
158 | Some event loops issue spurious readyness notifications, so you should |
201 | Some event loops issue spurious readyness notifications, so you should |
159 | always use non-blocking calls when reading/writing from/to your file |
202 | always use non-blocking calls when reading/writing from/to your file |
160 | handles. |
203 | handles. |
161 | |
204 | |
162 | Example: |
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163 | |
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164 | # wait for readability of STDIN, then read a line and disable the watcher |
205 | Example: wait for readability of STDIN, then read a line and disable the |
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206 | watcher. |
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207 | |
165 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
208 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
166 | chomp (my $input = <STDIN>); |
209 | chomp (my $input = <STDIN>); |
167 | warn "read: $input\n"; |
210 | warn "read: $input\n"; |
168 | undef $w; |
211 | undef $w; |
169 | }); |
212 | }); |
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172 | |
215 | |
173 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
216 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
174 | method with the following mandatory arguments: |
217 | method with the following mandatory arguments: |
175 | |
218 | |
176 | C<after> specifies after how many seconds (fractional values are |
219 | C<after> specifies after how many seconds (fractional values are |
177 | supported) should the timer activate. C<cb> the callback to invoke in that |
220 | supported) the callback should be invoked. C<cb> is the callback to invoke |
178 | case. |
221 | in that case. |
179 | |
222 | |
180 | The timer callback will be invoked at most once: if you want a repeating |
223 | Although the callback might get passed parameters, their value and |
181 | timer you have to create a new watcher (this is a limitation by both Tk |
224 | presence is undefined and you cannot rely on them. Portable AnyEvent |
182 | and Glib). |
225 | callbacks cannot use arguments passed to time watcher callbacks. |
183 | |
226 | |
184 | Example: |
227 | The callback will normally be invoked once only. If you specify another |
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228 | parameter, C<interval>, as a strictly positive number (> 0), then the |
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229 | callback will be invoked regularly at that interval (in fractional |
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230 | seconds) after the first invocation. If C<interval> is specified with a |
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231 | false value, then it is treated as if it were missing. |
185 | |
232 | |
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233 | The callback will be rescheduled before invoking the callback, but no |
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234 | attempt is done to avoid timer drift in most backends, so the interval is |
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235 | only approximate. |
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236 | |
186 | # fire an event after 7.7 seconds |
237 | Example: fire an event after 7.7 seconds. |
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238 | |
187 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
239 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
188 | warn "timeout\n"; |
240 | warn "timeout\n"; |
189 | }); |
241 | }); |
190 | |
242 | |
191 | # to cancel the timer: |
243 | # to cancel the timer: |
192 | undef $w; |
244 | undef $w; |
193 | |
245 | |
194 | Example 2: |
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195 | |
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196 | # fire an event after 0.5 seconds, then roughly every second |
246 | Example 2: fire an event after 0.5 seconds, then roughly every second. |
197 | my $w; |
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198 | |
247 | |
199 | my $cb = sub { |
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200 | # cancel the old timer while creating a new one |
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201 | $w = AnyEvent->timer (after => 1, cb => $cb); |
248 | my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub { |
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249 | warn "timeout\n"; |
202 | }; |
250 | }; |
203 | |
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204 | # start the "loop" by creating the first watcher |
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205 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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206 | |
251 | |
207 | =head3 TIMING ISSUES |
252 | =head3 TIMING ISSUES |
208 | |
253 | |
209 | There are two ways to handle timers: based on real time (relative, "fire |
254 | There are two ways to handle timers: based on real time (relative, "fire |
210 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
255 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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222 | timers. |
267 | timers. |
223 | |
268 | |
224 | AnyEvent always prefers relative timers, if available, matching the |
269 | AnyEvent always prefers relative timers, if available, matching the |
225 | AnyEvent API. |
270 | AnyEvent API. |
226 | |
271 | |
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272 | AnyEvent has two additional methods that return the "current time": |
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273 | |
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274 | =over 4 |
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275 | |
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276 | =item AnyEvent->time |
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277 | |
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278 | This returns the "current wallclock time" as a fractional number of |
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279 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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280 | return, and the result is guaranteed to be compatible with those). |
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281 | |
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282 | It progresses independently of any event loop processing, i.e. each call |
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283 | will check the system clock, which usually gets updated frequently. |
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284 | |
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285 | =item AnyEvent->now |
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286 | |
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287 | This also returns the "current wallclock time", but unlike C<time>, above, |
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288 | this value might change only once per event loop iteration, depending on |
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289 | the event loop (most return the same time as C<time>, above). This is the |
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290 | time that AnyEvent's timers get scheduled against. |
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291 | |
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292 | I<In almost all cases (in all cases if you don't care), this is the |
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293 | function to call when you want to know the current time.> |
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294 | |
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295 | This function is also often faster then C<< AnyEvent->time >>, and |
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296 | thus the preferred method if you want some timestamp (for example, |
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297 | L<AnyEvent::Handle> uses this to update it's activity timeouts). |
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298 | |
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299 | The rest of this section is only of relevance if you try to be very exact |
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300 | with your timing, you can skip it without bad conscience. |
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301 | |
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302 | For a practical example of when these times differ, consider L<Event::Lib> |
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303 | and L<EV> and the following set-up: |
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304 | |
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305 | The event loop is running and has just invoked one of your callback at |
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306 | time=500 (assume no other callbacks delay processing). In your callback, |
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307 | you wait a second by executing C<sleep 1> (blocking the process for a |
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308 | second) and then (at time=501) you create a relative timer that fires |
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309 | after three seconds. |
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310 | |
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311 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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312 | both return C<501>, because that is the current time, and the timer will |
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313 | be scheduled to fire at time=504 (C<501> + C<3>). |
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314 | |
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315 | With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current |
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316 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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317 | last event processing phase started. With L<EV>, your timer gets scheduled |
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318 | to run at time=503 (C<500> + C<3>). |
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319 | |
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320 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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321 | regardless of any delays introduced by event processing. However, most |
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322 | callbacks do not expect large delays in processing, so this causes a |
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323 | higher drift (and a lot more system calls to get the current time). |
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324 | |
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325 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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326 | the same time, regardless of how long event processing actually took. |
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327 | |
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328 | In either case, if you care (and in most cases, you don't), then you |
|
|
329 | can get whatever behaviour you want with any event loop, by taking the |
|
|
330 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
|
|
331 | account. |
|
|
332 | |
|
|
333 | =item AnyEvent->now_update |
|
|
334 | |
|
|
335 | Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache |
|
|
336 | the current time for each loop iteration (see the discussion of L<< |
|
|
337 | AnyEvent->now >>, above). |
|
|
338 | |
|
|
339 | When a callback runs for a long time (or when the process sleeps), then |
|
|
340 | this "current" time will differ substantially from the real time, which |
|
|
341 | might affect timers and time-outs. |
|
|
342 | |
|
|
343 | When this is the case, you can call this method, which will update the |
|
|
344 | event loop's idea of "current time". |
|
|
345 | |
|
|
346 | Note that updating the time I<might> cause some events to be handled. |
|
|
347 | |
|
|
348 | =back |
|
|
349 | |
227 | =head2 SIGNAL WATCHERS |
350 | =head2 SIGNAL WATCHERS |
228 | |
351 | |
229 | You can watch for signals using a signal watcher, C<signal> is the signal |
352 | You can watch for signals using a signal watcher, C<signal> is the signal |
230 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
353 | I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl |
231 | be invoked whenever a signal occurs. |
354 | callback to be invoked whenever a signal occurs. |
232 | |
355 | |
|
|
356 | Although the callback might get passed parameters, their value and |
|
|
357 | presence is undefined and you cannot rely on them. Portable AnyEvent |
|
|
358 | callbacks cannot use arguments passed to signal watcher callbacks. |
|
|
359 | |
233 | Multiple signal occurances can be clumped together into one callback |
360 | Multiple signal occurrences can be clumped together into one callback |
234 | invocation, and callback invocation will be synchronous. synchronous means |
361 | invocation, and callback invocation will be synchronous. Synchronous means |
235 | that it might take a while until the signal gets handled by the process, |
362 | that it might take a while until the signal gets handled by the process, |
236 | but it is guarenteed not to interrupt any other callbacks. |
363 | but it is guaranteed not to interrupt any other callbacks. |
237 | |
364 | |
238 | The main advantage of using these watchers is that you can share a signal |
365 | The main advantage of using these watchers is that you can share a signal |
239 | between multiple watchers. |
366 | between multiple watchers. |
240 | |
367 | |
241 | This watcher might use C<%SIG>, so programs overwriting those signals |
368 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
… | |
248 | =head2 CHILD PROCESS WATCHERS |
375 | =head2 CHILD PROCESS WATCHERS |
249 | |
376 | |
250 | You can also watch on a child process exit and catch its exit status. |
377 | You can also watch on a child process exit and catch its exit status. |
251 | |
378 | |
252 | The child process is specified by the C<pid> argument (if set to C<0>, it |
379 | The child process is specified by the C<pid> argument (if set to C<0>, it |
253 | watches for any child process exit). The watcher will trigger as often |
380 | watches for any child process exit). The watcher will triggered only when |
254 | as status change for the child are received. This works by installing a |
381 | the child process has finished and an exit status is available, not on |
255 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
382 | any trace events (stopped/continued). |
256 | and exit status (as returned by waitpid). |
|
|
257 | |
383 | |
258 | Example: wait for pid 1333 |
384 | The callback will be called with the pid and exit status (as returned by |
|
|
385 | waitpid), so unlike other watcher types, you I<can> rely on child watcher |
|
|
386 | callback arguments. |
259 | |
387 | |
|
|
388 | This watcher type works by installing a signal handler for C<SIGCHLD>, |
|
|
389 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
|
390 | random child processes (waiting for specific child processes, e.g. inside |
|
|
391 | C<system>, is just fine). |
|
|
392 | |
|
|
393 | There is a slight catch to child watchers, however: you usually start them |
|
|
394 | I<after> the child process was created, and this means the process could |
|
|
395 | have exited already (and no SIGCHLD will be sent anymore). |
|
|
396 | |
|
|
397 | Not all event models handle this correctly (neither POE nor IO::Async do, |
|
|
398 | see their AnyEvent::Impl manpages for details), but even for event models |
|
|
399 | that I<do> handle this correctly, they usually need to be loaded before |
|
|
400 | the process exits (i.e. before you fork in the first place). AnyEvent's |
|
|
401 | pure perl event loop handles all cases correctly regardless of when you |
|
|
402 | start the watcher. |
|
|
403 | |
|
|
404 | This means you cannot create a child watcher as the very first |
|
|
405 | thing in an AnyEvent program, you I<have> to create at least one |
|
|
406 | watcher before you C<fork> the child (alternatively, you can call |
|
|
407 | C<AnyEvent::detect>). |
|
|
408 | |
|
|
409 | Example: fork a process and wait for it |
|
|
410 | |
|
|
411 | my $done = AnyEvent->condvar; |
|
|
412 | |
|
|
413 | my $pid = fork or exit 5; |
|
|
414 | |
260 | my $w = AnyEvent->child ( |
415 | my $w = AnyEvent->child ( |
261 | pid => 1333, |
416 | pid => $pid, |
262 | cb => sub { |
417 | cb => sub { |
263 | my ($pid, $status) = @_; |
418 | my ($pid, $status) = @_; |
264 | warn "pid $pid exited with status $status"; |
419 | warn "pid $pid exited with status $status"; |
|
|
420 | $done->send; |
265 | }, |
421 | }, |
266 | ); |
422 | ); |
|
|
423 | |
|
|
424 | # do something else, then wait for process exit |
|
|
425 | $done->recv; |
|
|
426 | |
|
|
427 | =head2 IDLE WATCHERS |
|
|
428 | |
|
|
429 | Sometimes there is a need to do something, but it is not so important |
|
|
430 | to do it instantly, but only when there is nothing better to do. This |
|
|
431 | "nothing better to do" is usually defined to be "no other events need |
|
|
432 | attention by the event loop". |
|
|
433 | |
|
|
434 | Idle watchers ideally get invoked when the event loop has nothing |
|
|
435 | better to do, just before it would block the process to wait for new |
|
|
436 | events. Instead of blocking, the idle watcher is invoked. |
|
|
437 | |
|
|
438 | Most event loops unfortunately do not really support idle watchers (only |
|
|
439 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
|
|
440 | will simply call the callback "from time to time". |
|
|
441 | |
|
|
442 | Example: read lines from STDIN, but only process them when the |
|
|
443 | program is otherwise idle: |
|
|
444 | |
|
|
445 | my @lines; # read data |
|
|
446 | my $idle_w; |
|
|
447 | my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
448 | push @lines, scalar <STDIN>; |
|
|
449 | |
|
|
450 | # start an idle watcher, if not already done |
|
|
451 | $idle_w ||= AnyEvent->idle (cb => sub { |
|
|
452 | # handle only one line, when there are lines left |
|
|
453 | if (my $line = shift @lines) { |
|
|
454 | print "handled when idle: $line"; |
|
|
455 | } else { |
|
|
456 | # otherwise disable the idle watcher again |
|
|
457 | undef $idle_w; |
|
|
458 | } |
|
|
459 | }); |
|
|
460 | }); |
267 | |
461 | |
268 | =head2 CONDITION VARIABLES |
462 | =head2 CONDITION VARIABLES |
269 | |
463 | |
|
|
464 | If you are familiar with some event loops you will know that all of them |
|
|
465 | require you to run some blocking "loop", "run" or similar function that |
|
|
466 | will actively watch for new events and call your callbacks. |
|
|
467 | |
|
|
468 | AnyEvent is different, it expects somebody else to run the event loop and |
|
|
469 | will only block when necessary (usually when told by the user). |
|
|
470 | |
|
|
471 | The instrument to do that is called a "condition variable", so called |
|
|
472 | because they represent a condition that must become true. |
|
|
473 | |
270 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
474 | Condition variables can be created by calling the C<< AnyEvent->condvar |
271 | method without any arguments. |
475 | >> method, usually without arguments. The only argument pair allowed is |
272 | |
476 | |
273 | A condition variable waits for a condition - precisely that the C<< |
477 | C<cb>, which specifies a callback to be called when the condition variable |
274 | ->broadcast >> method has been called. |
478 | becomes true, with the condition variable as the first argument (but not |
|
|
479 | the results). |
275 | |
480 | |
276 | They are very useful to signal that a condition has been fulfilled, for |
481 | After creation, the condition variable is "false" until it becomes "true" |
|
|
482 | by calling the C<send> method (or calling the condition variable as if it |
|
|
483 | were a callback, read about the caveats in the description for the C<< |
|
|
484 | ->send >> method). |
|
|
485 | |
|
|
486 | Condition variables are similar to callbacks, except that you can |
|
|
487 | optionally wait for them. They can also be called merge points - points |
|
|
488 | in time where multiple outstanding events have been processed. And yet |
|
|
489 | another way to call them is transactions - each condition variable can be |
|
|
490 | used to represent a transaction, which finishes at some point and delivers |
|
|
491 | a result. |
|
|
492 | |
|
|
493 | Condition variables are very useful to signal that something has finished, |
277 | example, if you write a module that does asynchronous http requests, |
494 | for example, if you write a module that does asynchronous http requests, |
278 | then a condition variable would be the ideal candidate to signal the |
495 | then a condition variable would be the ideal candidate to signal the |
279 | availability of results. |
496 | availability of results. The user can either act when the callback is |
|
|
497 | called or can synchronously C<< ->recv >> for the results. |
280 | |
498 | |
281 | You can also use condition variables to block your main program until |
499 | You can also use them to simulate traditional event loops - for example, |
282 | an event occurs - for example, you could C<< ->wait >> in your main |
500 | you can block your main program until an event occurs - for example, you |
283 | program until the user clicks the Quit button in your app, which would C<< |
501 | could C<< ->recv >> in your main program until the user clicks the Quit |
284 | ->broadcast >> the "quit" event. |
502 | button of your app, which would C<< ->send >> the "quit" event. |
285 | |
503 | |
286 | Note that condition variables recurse into the event loop - if you have |
504 | Note that condition variables recurse into the event loop - if you have |
287 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
505 | two pieces of code that call C<< ->recv >> in a round-robin fashion, you |
288 | lose. Therefore, condition variables are good to export to your caller, but |
506 | lose. Therefore, condition variables are good to export to your caller, but |
289 | you should avoid making a blocking wait yourself, at least in callbacks, |
507 | you should avoid making a blocking wait yourself, at least in callbacks, |
290 | as this asks for trouble. |
508 | as this asks for trouble. |
291 | |
509 | |
292 | This object has two methods: |
510 | Condition variables are represented by hash refs in perl, and the keys |
|
|
511 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
|
|
512 | easy (it is often useful to build your own transaction class on top of |
|
|
513 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
|
|
514 | it's C<new> method in your own C<new> method. |
|
|
515 | |
|
|
516 | There are two "sides" to a condition variable - the "producer side" which |
|
|
517 | eventually calls C<< -> send >>, and the "consumer side", which waits |
|
|
518 | for the send to occur. |
|
|
519 | |
|
|
520 | Example: wait for a timer. |
|
|
521 | |
|
|
522 | # wait till the result is ready |
|
|
523 | my $result_ready = AnyEvent->condvar; |
|
|
524 | |
|
|
525 | # do something such as adding a timer |
|
|
526 | # or socket watcher the calls $result_ready->send |
|
|
527 | # when the "result" is ready. |
|
|
528 | # in this case, we simply use a timer: |
|
|
529 | my $w = AnyEvent->timer ( |
|
|
530 | after => 1, |
|
|
531 | cb => sub { $result_ready->send }, |
|
|
532 | ); |
|
|
533 | |
|
|
534 | # this "blocks" (while handling events) till the callback |
|
|
535 | # calls send |
|
|
536 | $result_ready->recv; |
|
|
537 | |
|
|
538 | Example: wait for a timer, but take advantage of the fact that |
|
|
539 | condition variables are also code references. |
|
|
540 | |
|
|
541 | my $done = AnyEvent->condvar; |
|
|
542 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
|
|
543 | $done->recv; |
|
|
544 | |
|
|
545 | Example: Imagine an API that returns a condvar and doesn't support |
|
|
546 | callbacks. This is how you make a synchronous call, for example from |
|
|
547 | the main program: |
|
|
548 | |
|
|
549 | use AnyEvent::CouchDB; |
|
|
550 | |
|
|
551 | ... |
|
|
552 | |
|
|
553 | my @info = $couchdb->info->recv; |
|
|
554 | |
|
|
555 | And this is how you would just ste a callback to be called whenever the |
|
|
556 | results are available: |
|
|
557 | |
|
|
558 | $couchdb->info->cb (sub { |
|
|
559 | my @info = $_[0]->recv; |
|
|
560 | }); |
|
|
561 | |
|
|
562 | =head3 METHODS FOR PRODUCERS |
|
|
563 | |
|
|
564 | These methods should only be used by the producing side, i.e. the |
|
|
565 | code/module that eventually sends the signal. Note that it is also |
|
|
566 | the producer side which creates the condvar in most cases, but it isn't |
|
|
567 | uncommon for the consumer to create it as well. |
293 | |
568 | |
294 | =over 4 |
569 | =over 4 |
295 | |
570 | |
|
|
571 | =item $cv->send (...) |
|
|
572 | |
|
|
573 | Flag the condition as ready - a running C<< ->recv >> and all further |
|
|
574 | calls to C<recv> will (eventually) return after this method has been |
|
|
575 | called. If nobody is waiting the send will be remembered. |
|
|
576 | |
|
|
577 | If a callback has been set on the condition variable, it is called |
|
|
578 | immediately from within send. |
|
|
579 | |
|
|
580 | Any arguments passed to the C<send> call will be returned by all |
|
|
581 | future C<< ->recv >> calls. |
|
|
582 | |
|
|
583 | Condition variables are overloaded so one can call them directly |
|
|
584 | (as a code reference). Calling them directly is the same as calling |
|
|
585 | C<send>. Note, however, that many C-based event loops do not handle |
|
|
586 | overloading, so as tempting as it may be, passing a condition variable |
|
|
587 | instead of a callback does not work. Both the pure perl and EV loops |
|
|
588 | support overloading, however, as well as all functions that use perl to |
|
|
589 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
|
|
590 | example). |
|
|
591 | |
|
|
592 | =item $cv->croak ($error) |
|
|
593 | |
|
|
594 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
|
|
595 | C<Carp::croak> with the given error message/object/scalar. |
|
|
596 | |
|
|
597 | This can be used to signal any errors to the condition variable |
|
|
598 | user/consumer. |
|
|
599 | |
|
|
600 | =item $cv->begin ([group callback]) |
|
|
601 | |
296 | =item $cv->wait |
602 | =item $cv->end |
297 | |
603 | |
298 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
604 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
605 | |
|
|
606 | These two methods can be used to combine many transactions/events into |
|
|
607 | one. For example, a function that pings many hosts in parallel might want |
|
|
608 | to use a condition variable for the whole process. |
|
|
609 | |
|
|
610 | Every call to C<< ->begin >> will increment a counter, and every call to |
|
|
611 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
|
|
612 | >>, the (last) callback passed to C<begin> will be executed. That callback |
|
|
613 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
|
|
614 | callback was set, C<send> will be called without any arguments. |
|
|
615 | |
|
|
616 | Let's clarify this with the ping example: |
|
|
617 | |
|
|
618 | my $cv = AnyEvent->condvar; |
|
|
619 | |
|
|
620 | my %result; |
|
|
621 | $cv->begin (sub { $cv->send (\%result) }); |
|
|
622 | |
|
|
623 | for my $host (@list_of_hosts) { |
|
|
624 | $cv->begin; |
|
|
625 | ping_host_then_call_callback $host, sub { |
|
|
626 | $result{$host} = ...; |
|
|
627 | $cv->end; |
|
|
628 | }; |
|
|
629 | } |
|
|
630 | |
|
|
631 | $cv->end; |
|
|
632 | |
|
|
633 | This code fragment supposedly pings a number of hosts and calls |
|
|
634 | C<send> after results for all then have have been gathered - in any |
|
|
635 | order. To achieve this, the code issues a call to C<begin> when it starts |
|
|
636 | each ping request and calls C<end> when it has received some result for |
|
|
637 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
|
|
638 | results arrive is not relevant. |
|
|
639 | |
|
|
640 | There is an additional bracketing call to C<begin> and C<end> outside the |
|
|
641 | loop, which serves two important purposes: first, it sets the callback |
|
|
642 | to be called once the counter reaches C<0>, and second, it ensures that |
|
|
643 | C<send> is called even when C<no> hosts are being pinged (the loop |
|
|
644 | doesn't execute once). |
|
|
645 | |
|
|
646 | This is the general pattern when you "fan out" into multiple subrequests: |
|
|
647 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
|
|
648 | is called at least once, and then, for each subrequest you start, call |
|
|
649 | C<begin> and for each subrequest you finish, call C<end>. |
|
|
650 | |
|
|
651 | =back |
|
|
652 | |
|
|
653 | =head3 METHODS FOR CONSUMERS |
|
|
654 | |
|
|
655 | These methods should only be used by the consuming side, i.e. the |
|
|
656 | code awaits the condition. |
|
|
657 | |
|
|
658 | =over 4 |
|
|
659 | |
|
|
660 | =item $cv->recv |
|
|
661 | |
|
|
662 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
299 | called on c<$cv>, while servicing other watchers normally. |
663 | >> methods have been called on c<$cv>, while servicing other watchers |
|
|
664 | normally. |
300 | |
665 | |
301 | You can only wait once on a condition - additional calls will return |
666 | You can only wait once on a condition - additional calls are valid but |
302 | immediately. |
667 | will return immediately. |
|
|
668 | |
|
|
669 | If an error condition has been set by calling C<< ->croak >>, then this |
|
|
670 | function will call C<croak>. |
|
|
671 | |
|
|
672 | In list context, all parameters passed to C<send> will be returned, |
|
|
673 | in scalar context only the first one will be returned. |
303 | |
674 | |
304 | Not all event models support a blocking wait - some die in that case |
675 | Not all event models support a blocking wait - some die in that case |
305 | (programs might want to do that to stay interactive), so I<if you are |
676 | (programs might want to do that to stay interactive), so I<if you are |
306 | using this from a module, never require a blocking wait>, but let the |
677 | using this from a module, never require a blocking wait>, but let the |
307 | caller decide whether the call will block or not (for example, by coupling |
678 | caller decide whether the call will block or not (for example, by coupling |
308 | condition variables with some kind of request results and supporting |
679 | condition variables with some kind of request results and supporting |
309 | callbacks so the caller knows that getting the result will not block, |
680 | callbacks so the caller knows that getting the result will not block, |
310 | while still suppporting blocking waits if the caller so desires). |
681 | while still supporting blocking waits if the caller so desires). |
311 | |
682 | |
312 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
683 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
313 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
684 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
314 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
685 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
315 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
686 | can supply. |
316 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
|
|
317 | from different coroutines, however). |
|
|
318 | |
687 | |
319 | =item $cv->broadcast |
688 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
|
|
689 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
|
|
690 | versions and also integrates coroutines into AnyEvent, making blocking |
|
|
691 | C<< ->recv >> calls perfectly safe as long as they are done from another |
|
|
692 | coroutine (one that doesn't run the event loop). |
320 | |
693 | |
321 | Flag the condition as ready - a running C<< ->wait >> and all further |
694 | You can ensure that C<< -recv >> never blocks by setting a callback and |
322 | calls to C<wait> will (eventually) return after this method has been |
695 | only calling C<< ->recv >> from within that callback (or at a later |
323 | called. If nobody is waiting the broadcast will be remembered.. |
696 | time). This will work even when the event loop does not support blocking |
|
|
697 | waits otherwise. |
|
|
698 | |
|
|
699 | =item $bool = $cv->ready |
|
|
700 | |
|
|
701 | Returns true when the condition is "true", i.e. whether C<send> or |
|
|
702 | C<croak> have been called. |
|
|
703 | |
|
|
704 | =item $cb = $cv->cb ($cb->($cv)) |
|
|
705 | |
|
|
706 | This is a mutator function that returns the callback set and optionally |
|
|
707 | replaces it before doing so. |
|
|
708 | |
|
|
709 | The callback will be called when the condition becomes "true", i.e. when |
|
|
710 | C<send> or C<croak> are called, with the only argument being the condition |
|
|
711 | variable itself. Calling C<recv> inside the callback or at any later time |
|
|
712 | is guaranteed not to block. |
324 | |
713 | |
325 | =back |
714 | =back |
326 | |
|
|
327 | Example: |
|
|
328 | |
|
|
329 | # wait till the result is ready |
|
|
330 | my $result_ready = AnyEvent->condvar; |
|
|
331 | |
|
|
332 | # do something such as adding a timer |
|
|
333 | # or socket watcher the calls $result_ready->broadcast |
|
|
334 | # when the "result" is ready. |
|
|
335 | # in this case, we simply use a timer: |
|
|
336 | my $w = AnyEvent->timer ( |
|
|
337 | after => 1, |
|
|
338 | cb => sub { $result_ready->broadcast }, |
|
|
339 | ); |
|
|
340 | |
|
|
341 | # this "blocks" (while handling events) till the watcher |
|
|
342 | # calls broadcast |
|
|
343 | $result_ready->wait; |
|
|
344 | |
715 | |
345 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
716 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
346 | |
717 | |
347 | =over 4 |
718 | =over 4 |
348 | |
719 | |
… | |
… | |
354 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
725 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
355 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
726 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
356 | |
727 | |
357 | The known classes so far are: |
728 | The known classes so far are: |
358 | |
729 | |
359 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
360 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
361 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
730 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
362 | AnyEvent::Impl::Event based on Event, second best choice. |
731 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
732 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
363 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
733 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
364 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
734 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
365 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
366 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
735 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
367 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
736 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
368 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
737 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
|
|
738 | |
|
|
739 | # warning, support for IO::Async is only partial, as it is too broken |
|
|
740 | # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async. |
|
|
741 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs). |
369 | |
742 | |
370 | There is no support for WxWidgets, as WxWidgets has no support for |
743 | There is no support for WxWidgets, as WxWidgets has no support for |
371 | watching file handles. However, you can use WxWidgets through the |
744 | watching file handles. However, you can use WxWidgets through the |
372 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
745 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
373 | second, which was considered to be too horrible to even consider for |
746 | second, which was considered to be too horrible to even consider for |
… | |
… | |
382 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
755 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
383 | if necessary. You should only call this function right before you would |
756 | if necessary. You should only call this function right before you would |
384 | have created an AnyEvent watcher anyway, that is, as late as possible at |
757 | have created an AnyEvent watcher anyway, that is, as late as possible at |
385 | runtime. |
758 | runtime. |
386 | |
759 | |
|
|
760 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
761 | |
|
|
762 | Arranges for the code block to be executed as soon as the event model is |
|
|
763 | autodetected (or immediately if this has already happened). |
|
|
764 | |
|
|
765 | If called in scalar or list context, then it creates and returns an object |
|
|
766 | that automatically removes the callback again when it is destroyed. See |
|
|
767 | L<Coro::BDB> for a case where this is useful. |
|
|
768 | |
|
|
769 | =item @AnyEvent::post_detect |
|
|
770 | |
|
|
771 | If there are any code references in this array (you can C<push> to it |
|
|
772 | before or after loading AnyEvent), then they will called directly after |
|
|
773 | the event loop has been chosen. |
|
|
774 | |
|
|
775 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
776 | if it contains a true value then the event loop has already been detected, |
|
|
777 | and the array will be ignored. |
|
|
778 | |
|
|
779 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
780 | |
387 | =back |
781 | =back |
388 | |
782 | |
389 | =head1 WHAT TO DO IN A MODULE |
783 | =head1 WHAT TO DO IN A MODULE |
390 | |
784 | |
391 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
785 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
394 | Be careful when you create watchers in the module body - AnyEvent will |
788 | Be careful when you create watchers in the module body - AnyEvent will |
395 | decide which event module to use as soon as the first method is called, so |
789 | decide which event module to use as soon as the first method is called, so |
396 | by calling AnyEvent in your module body you force the user of your module |
790 | by calling AnyEvent in your module body you force the user of your module |
397 | to load the event module first. |
791 | to load the event module first. |
398 | |
792 | |
399 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
793 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
400 | the C<< ->broadcast >> method has been called on it already. This is |
794 | the C<< ->send >> method has been called on it already. This is |
401 | because it will stall the whole program, and the whole point of using |
795 | because it will stall the whole program, and the whole point of using |
402 | events is to stay interactive. |
796 | events is to stay interactive. |
403 | |
797 | |
404 | It is fine, however, to call C<< ->wait >> when the user of your module |
798 | It is fine, however, to call C<< ->recv >> when the user of your module |
405 | requests it (i.e. if you create a http request object ad have a method |
799 | requests it (i.e. if you create a http request object ad have a method |
406 | called C<results> that returns the results, it should call C<< ->wait >> |
800 | called C<results> that returns the results, it should call C<< ->recv >> |
407 | freely, as the user of your module knows what she is doing. always). |
801 | freely, as the user of your module knows what she is doing. always). |
408 | |
802 | |
409 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
803 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
410 | |
804 | |
411 | There will always be a single main program - the only place that should |
805 | There will always be a single main program - the only place that should |
… | |
… | |
413 | |
807 | |
414 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
808 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
415 | do anything special (it does not need to be event-based) and let AnyEvent |
809 | do anything special (it does not need to be event-based) and let AnyEvent |
416 | decide which implementation to chose if some module relies on it. |
810 | decide which implementation to chose if some module relies on it. |
417 | |
811 | |
418 | If the main program relies on a specific event model. For example, in |
812 | If the main program relies on a specific event model - for example, in |
419 | Gtk2 programs you have to rely on the Glib module. You should load the |
813 | Gtk2 programs you have to rely on the Glib module - you should load the |
420 | event module before loading AnyEvent or any module that uses it: generally |
814 | event module before loading AnyEvent or any module that uses it: generally |
421 | speaking, you should load it as early as possible. The reason is that |
815 | speaking, you should load it as early as possible. The reason is that |
422 | modules might create watchers when they are loaded, and AnyEvent will |
816 | modules might create watchers when they are loaded, and AnyEvent will |
423 | decide on the event model to use as soon as it creates watchers, and it |
817 | decide on the event model to use as soon as it creates watchers, and it |
424 | might chose the wrong one unless you load the correct one yourself. |
818 | might chose the wrong one unless you load the correct one yourself. |
425 | |
819 | |
426 | You can chose to use a rather inefficient pure-perl implementation by |
820 | You can chose to use a pure-perl implementation by loading the |
427 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
821 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
428 | behaviour everywhere, but letting AnyEvent chose is generally better. |
822 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
823 | |
|
|
824 | =head2 MAINLOOP EMULATION |
|
|
825 | |
|
|
826 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
827 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
828 | |
|
|
829 | In that case, you can use a condition variable like this: |
|
|
830 | |
|
|
831 | AnyEvent->condvar->recv; |
|
|
832 | |
|
|
833 | This has the effect of entering the event loop and looping forever. |
|
|
834 | |
|
|
835 | Note that usually your program has some exit condition, in which case |
|
|
836 | it is better to use the "traditional" approach of storing a condition |
|
|
837 | variable somewhere, waiting for it, and sending it when the program should |
|
|
838 | exit cleanly. |
|
|
839 | |
|
|
840 | |
|
|
841 | =head1 OTHER MODULES |
|
|
842 | |
|
|
843 | The following is a non-exhaustive list of additional modules that use |
|
|
844 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
845 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
846 | available via CPAN. |
|
|
847 | |
|
|
848 | =over 4 |
|
|
849 | |
|
|
850 | =item L<AnyEvent::Util> |
|
|
851 | |
|
|
852 | Contains various utility functions that replace often-used but blocking |
|
|
853 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
854 | |
|
|
855 | =item L<AnyEvent::Socket> |
|
|
856 | |
|
|
857 | Provides various utility functions for (internet protocol) sockets, |
|
|
858 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
859 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
860 | |
|
|
861 | =item L<AnyEvent::Handle> |
|
|
862 | |
|
|
863 | Provide read and write buffers, manages watchers for reads and writes, |
|
|
864 | supports raw and formatted I/O, I/O queued and fully transparent and |
|
|
865 | non-blocking SSL/TLS. |
|
|
866 | |
|
|
867 | =item L<AnyEvent::DNS> |
|
|
868 | |
|
|
869 | Provides rich asynchronous DNS resolver capabilities. |
|
|
870 | |
|
|
871 | =item L<AnyEvent::HTTP> |
|
|
872 | |
|
|
873 | A simple-to-use HTTP library that is capable of making a lot of concurrent |
|
|
874 | HTTP requests. |
|
|
875 | |
|
|
876 | =item L<AnyEvent::HTTPD> |
|
|
877 | |
|
|
878 | Provides a simple web application server framework. |
|
|
879 | |
|
|
880 | =item L<AnyEvent::FastPing> |
|
|
881 | |
|
|
882 | The fastest ping in the west. |
|
|
883 | |
|
|
884 | =item L<AnyEvent::DBI> |
|
|
885 | |
|
|
886 | Executes L<DBI> requests asynchronously in a proxy process. |
|
|
887 | |
|
|
888 | =item L<AnyEvent::AIO> |
|
|
889 | |
|
|
890 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
891 | programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent |
|
|
892 | together. |
|
|
893 | |
|
|
894 | =item L<AnyEvent::BDB> |
|
|
895 | |
|
|
896 | Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses |
|
|
897 | L<BDB> and AnyEvent together. |
|
|
898 | |
|
|
899 | =item L<AnyEvent::GPSD> |
|
|
900 | |
|
|
901 | A non-blocking interface to gpsd, a daemon delivering GPS information. |
|
|
902 | |
|
|
903 | =item L<AnyEvent::IGS> |
|
|
904 | |
|
|
905 | A non-blocking interface to the Internet Go Server protocol (used by |
|
|
906 | L<App::IGS>). |
|
|
907 | |
|
|
908 | =item L<AnyEvent::IRC> |
|
|
909 | |
|
|
910 | AnyEvent based IRC client module family (replacing the older Net::IRC3). |
|
|
911 | |
|
|
912 | =item L<Net::XMPP2> |
|
|
913 | |
|
|
914 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
915 | |
|
|
916 | =item L<Net::FCP> |
|
|
917 | |
|
|
918 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
919 | of AnyEvent. |
|
|
920 | |
|
|
921 | =item L<Event::ExecFlow> |
|
|
922 | |
|
|
923 | High level API for event-based execution flow control. |
|
|
924 | |
|
|
925 | =item L<Coro> |
|
|
926 | |
|
|
927 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
928 | |
|
|
929 | =item L<IO::Lambda> |
|
|
930 | |
|
|
931 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
932 | |
|
|
933 | =back |
429 | |
934 | |
430 | =cut |
935 | =cut |
431 | |
936 | |
432 | package AnyEvent; |
937 | package AnyEvent; |
433 | |
938 | |
434 | no warnings; |
939 | no warnings; |
435 | use strict; |
940 | use strict qw(vars subs); |
436 | |
941 | |
437 | use Carp; |
942 | use Carp; |
438 | |
943 | |
439 | our $VERSION = '3.3'; |
944 | our $VERSION = 4.42; |
440 | our $MODEL; |
945 | our $MODEL; |
441 | |
946 | |
442 | our $AUTOLOAD; |
947 | our $AUTOLOAD; |
443 | our @ISA; |
948 | our @ISA; |
444 | |
949 | |
|
|
950 | our @REGISTRY; |
|
|
951 | |
|
|
952 | our $WIN32; |
|
|
953 | |
|
|
954 | BEGIN { |
|
|
955 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
|
|
956 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
|
|
957 | |
|
|
958 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
959 | if ${^TAINT}; |
|
|
960 | } |
|
|
961 | |
445 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
962 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
446 | |
963 | |
447 | our @REGISTRY; |
964 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
965 | |
|
|
966 | { |
|
|
967 | my $idx; |
|
|
968 | $PROTOCOL{$_} = ++$idx |
|
|
969 | for reverse split /\s*,\s*/, |
|
|
970 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
971 | } |
448 | |
972 | |
449 | my @models = ( |
973 | my @models = ( |
450 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
451 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
452 | [EV:: => AnyEvent::Impl::EV::], |
974 | [EV:: => AnyEvent::Impl::EV::], |
453 | [Event:: => AnyEvent::Impl::Event::], |
975 | [Event:: => AnyEvent::Impl::Event::], |
454 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
455 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
456 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
457 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
458 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
976 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
459 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
977 | # everything below here will not be autoprobed |
|
|
978 | # as the pureperl backend should work everywhere |
|
|
979 | # and is usually faster |
|
|
980 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
981 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
460 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
982 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
461 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
983 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
462 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
984 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
985 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
986 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
987 | # IO::Async is just too broken - we would need workaorunds for its |
|
|
988 | # byzantine signal and broken child handling, among others. |
|
|
989 | # IO::Async is rather hard to detect, as it doesn't have any |
|
|
990 | # obvious default class. |
|
|
991 | # [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
992 | # [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
993 | # [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program |
463 | ); |
994 | ); |
464 | |
995 | |
465 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
996 | our %method = map +($_ => 1), |
|
|
997 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
|
|
998 | |
|
|
999 | our @post_detect; |
|
|
1000 | |
|
|
1001 | sub post_detect(&) { |
|
|
1002 | my ($cb) = @_; |
|
|
1003 | |
|
|
1004 | if ($MODEL) { |
|
|
1005 | $cb->(); |
|
|
1006 | |
|
|
1007 | 1 |
|
|
1008 | } else { |
|
|
1009 | push @post_detect, $cb; |
|
|
1010 | |
|
|
1011 | defined wantarray |
|
|
1012 | ? bless \$cb, "AnyEvent::Util::postdetect" |
|
|
1013 | : () |
|
|
1014 | } |
|
|
1015 | } |
|
|
1016 | |
|
|
1017 | sub AnyEvent::Util::postdetect::DESTROY { |
|
|
1018 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
1019 | } |
466 | |
1020 | |
467 | sub detect() { |
1021 | sub detect() { |
468 | unless ($MODEL) { |
1022 | unless ($MODEL) { |
469 | no strict 'refs'; |
1023 | no strict 'refs'; |
|
|
1024 | local $SIG{__DIE__}; |
470 | |
1025 | |
471 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
1026 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
472 | my $model = "AnyEvent::Impl::$1"; |
1027 | my $model = "AnyEvent::Impl::$1"; |
473 | if (eval "require $model") { |
1028 | if (eval "require $model") { |
474 | $MODEL = $model; |
1029 | $MODEL = $model; |
… | |
… | |
504 | last; |
1059 | last; |
505 | } |
1060 | } |
506 | } |
1061 | } |
507 | |
1062 | |
508 | $MODEL |
1063 | $MODEL |
509 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
1064 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; |
510 | } |
1065 | } |
511 | } |
1066 | } |
512 | |
1067 | |
|
|
1068 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
1069 | |
513 | unshift @ISA, $MODEL; |
1070 | unshift @ISA, $MODEL; |
514 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
1071 | |
|
|
1072 | require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; |
|
|
1073 | |
|
|
1074 | (shift @post_detect)->() while @post_detect; |
515 | } |
1075 | } |
516 | |
1076 | |
517 | $MODEL |
1077 | $MODEL |
518 | } |
1078 | } |
519 | |
1079 | |
… | |
… | |
527 | |
1087 | |
528 | my $class = shift; |
1088 | my $class = shift; |
529 | $class->$func (@_); |
1089 | $class->$func (@_); |
530 | } |
1090 | } |
531 | |
1091 | |
|
|
1092 | # utility function to dup a filehandle. this is used by many backends |
|
|
1093 | # to support binding more than one watcher per filehandle (they usually |
|
|
1094 | # allow only one watcher per fd, so we dup it to get a different one). |
|
|
1095 | sub _dupfh($$;$$) { |
|
|
1096 | my ($poll, $fh, $r, $w) = @_; |
|
|
1097 | |
|
|
1098 | # cygwin requires the fh mode to be matching, unix doesn't |
|
|
1099 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
|
|
1100 | : $poll eq "w" ? ($w, ">") |
|
|
1101 | : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; |
|
|
1102 | |
|
|
1103 | open my $fh2, "$mode&" . fileno $fh |
|
|
1104 | or die "cannot dup() filehandle: $!,"; |
|
|
1105 | |
|
|
1106 | # we assume CLOEXEC is already set by perl in all important cases |
|
|
1107 | |
|
|
1108 | ($fh2, $rw) |
|
|
1109 | } |
|
|
1110 | |
532 | package AnyEvent::Base; |
1111 | package AnyEvent::Base; |
533 | |
1112 | |
|
|
1113 | # default implementations for many methods |
|
|
1114 | |
|
|
1115 | BEGIN { |
|
|
1116 | if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { |
|
|
1117 | *_time = \&Time::HiRes::time; |
|
|
1118 | # if (eval "use POSIX (); (POSIX::times())... |
|
|
1119 | } else { |
|
|
1120 | *_time = sub { time }; # epic fail |
|
|
1121 | } |
|
|
1122 | } |
|
|
1123 | |
|
|
1124 | sub time { _time } |
|
|
1125 | sub now { _time } |
|
|
1126 | sub now_update { } |
|
|
1127 | |
534 | # default implementation for ->condvar, ->wait, ->broadcast |
1128 | # default implementation for ->condvar |
535 | |
1129 | |
536 | sub condvar { |
1130 | sub condvar { |
537 | bless \my $flag, "AnyEvent::Base::CondVar" |
1131 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" |
538 | } |
|
|
539 | |
|
|
540 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
541 | ${$_[0]}++; |
|
|
542 | } |
|
|
543 | |
|
|
544 | sub AnyEvent::Base::CondVar::wait { |
|
|
545 | AnyEvent->one_event while !${$_[0]}; |
|
|
546 | } |
1132 | } |
547 | |
1133 | |
548 | # default implementation for ->signal |
1134 | # default implementation for ->signal |
549 | |
1135 | |
550 | our %SIG_CB; |
1136 | our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); |
|
|
1137 | |
|
|
1138 | sub _signal_exec { |
|
|
1139 | sysread $SIGPIPE_R, my $dummy, 4; |
|
|
1140 | |
|
|
1141 | while (%SIG_EV) { |
|
|
1142 | for (keys %SIG_EV) { |
|
|
1143 | delete $SIG_EV{$_}; |
|
|
1144 | $_->() for values %{ $SIG_CB{$_} || {} }; |
|
|
1145 | } |
|
|
1146 | } |
|
|
1147 | } |
551 | |
1148 | |
552 | sub signal { |
1149 | sub signal { |
553 | my (undef, %arg) = @_; |
1150 | my (undef, %arg) = @_; |
554 | |
1151 | |
|
|
1152 | unless ($SIGPIPE_R) { |
|
|
1153 | require Fcntl; |
|
|
1154 | |
|
|
1155 | if (AnyEvent::WIN32) { |
|
|
1156 | require AnyEvent::Util; |
|
|
1157 | |
|
|
1158 | ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); |
|
|
1159 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; |
|
|
1160 | AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case |
|
|
1161 | } else { |
|
|
1162 | pipe $SIGPIPE_R, $SIGPIPE_W; |
|
|
1163 | fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; |
|
|
1164 | fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case |
|
|
1165 | |
|
|
1166 | # not strictly required, as $^F is normally 2, but let's make sure... |
|
|
1167 | fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1168 | fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; |
|
|
1169 | } |
|
|
1170 | |
|
|
1171 | $SIGPIPE_R |
|
|
1172 | or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; |
|
|
1173 | |
|
|
1174 | $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); |
|
|
1175 | } |
|
|
1176 | |
555 | my $signal = uc $arg{signal} |
1177 | my $signal = uc $arg{signal} |
556 | or Carp::croak "required option 'signal' is missing"; |
1178 | or Carp::croak "required option 'signal' is missing"; |
557 | |
1179 | |
558 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
1180 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
559 | $SIG{$signal} ||= sub { |
1181 | $SIG{$signal} ||= sub { |
560 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
1182 | local $!; |
|
|
1183 | syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; |
|
|
1184 | undef $SIG_EV{$signal}; |
561 | }; |
1185 | }; |
562 | |
1186 | |
563 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
1187 | bless [$signal, $arg{cb}], "AnyEvent::Base::signal" |
564 | } |
1188 | } |
565 | |
1189 | |
566 | sub AnyEvent::Base::Signal::DESTROY { |
1190 | sub AnyEvent::Base::signal::DESTROY { |
567 | my ($signal, $cb) = @{$_[0]}; |
1191 | my ($signal, $cb) = @{$_[0]}; |
568 | |
1192 | |
569 | delete $SIG_CB{$signal}{$cb}; |
1193 | delete $SIG_CB{$signal}{$cb}; |
570 | |
1194 | |
|
|
1195 | # delete doesn't work with older perls - they then |
|
|
1196 | # print weird messages, or just unconditionally exit |
|
|
1197 | # instead of getting the default action. |
571 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
1198 | undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; |
572 | } |
1199 | } |
573 | |
1200 | |
574 | # default implementation for ->child |
1201 | # default implementation for ->child |
575 | |
1202 | |
576 | our %PID_CB; |
1203 | our %PID_CB; |
577 | our $CHLD_W; |
1204 | our $CHLD_W; |
578 | our $CHLD_DELAY_W; |
1205 | our $CHLD_DELAY_W; |
579 | our $PID_IDLE; |
|
|
580 | our $WNOHANG; |
1206 | our $WNOHANG; |
581 | |
1207 | |
582 | sub _child_wait { |
1208 | sub _sigchld { |
583 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
1209 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
584 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
1210 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
585 | (values %{ $PID_CB{0} || {} }); |
1211 | (values %{ $PID_CB{0} || {} }); |
586 | } |
1212 | } |
587 | |
|
|
588 | undef $PID_IDLE; |
|
|
589 | } |
|
|
590 | |
|
|
591 | sub _sigchld { |
|
|
592 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
593 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
594 | undef $CHLD_DELAY_W; |
|
|
595 | &_child_wait; |
|
|
596 | }); |
|
|
597 | } |
1213 | } |
598 | |
1214 | |
599 | sub child { |
1215 | sub child { |
600 | my (undef, %arg) = @_; |
1216 | my (undef, %arg) = @_; |
601 | |
1217 | |
602 | defined (my $pid = $arg{pid} + 0) |
1218 | defined (my $pid = $arg{pid} + 0) |
603 | or Carp::croak "required option 'pid' is missing"; |
1219 | or Carp::croak "required option 'pid' is missing"; |
604 | |
1220 | |
605 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
1221 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
606 | |
1222 | |
607 | unless ($WNOHANG) { |
|
|
608 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
1223 | $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; |
609 | } |
|
|
610 | |
1224 | |
611 | unless ($CHLD_W) { |
1225 | unless ($CHLD_W) { |
612 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
1226 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
613 | # child could be a zombie already, so make at least one round |
1227 | # child could be a zombie already, so make at least one round |
614 | &_sigchld; |
1228 | &_sigchld; |
615 | } |
1229 | } |
616 | |
1230 | |
617 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
1231 | bless [$pid, $arg{cb}], "AnyEvent::Base::child" |
618 | } |
1232 | } |
619 | |
1233 | |
620 | sub AnyEvent::Base::Child::DESTROY { |
1234 | sub AnyEvent::Base::child::DESTROY { |
621 | my ($pid, $cb) = @{$_[0]}; |
1235 | my ($pid, $cb) = @{$_[0]}; |
622 | |
1236 | |
623 | delete $PID_CB{$pid}{$cb}; |
1237 | delete $PID_CB{$pid}{$cb}; |
624 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
1238 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
625 | |
1239 | |
626 | undef $CHLD_W unless keys %PID_CB; |
1240 | undef $CHLD_W unless keys %PID_CB; |
627 | } |
1241 | } |
|
|
1242 | |
|
|
1243 | # idle emulation is done by simply using a timer, regardless |
|
|
1244 | # of whether the process is idle or not, and not letting |
|
|
1245 | # the callback use more than 50% of the time. |
|
|
1246 | sub idle { |
|
|
1247 | my (undef, %arg) = @_; |
|
|
1248 | |
|
|
1249 | my ($cb, $w, $rcb) = $arg{cb}; |
|
|
1250 | |
|
|
1251 | $rcb = sub { |
|
|
1252 | if ($cb) { |
|
|
1253 | $w = _time; |
|
|
1254 | &$cb; |
|
|
1255 | $w = _time - $w; |
|
|
1256 | |
|
|
1257 | # never use more then 50% of the time for the idle watcher, |
|
|
1258 | # within some limits |
|
|
1259 | $w = 0.0001 if $w < 0.0001; |
|
|
1260 | $w = 5 if $w > 5; |
|
|
1261 | |
|
|
1262 | $w = AnyEvent->timer (after => $w, cb => $rcb); |
|
|
1263 | } else { |
|
|
1264 | # clean up... |
|
|
1265 | undef $w; |
|
|
1266 | undef $rcb; |
|
|
1267 | } |
|
|
1268 | }; |
|
|
1269 | |
|
|
1270 | $w = AnyEvent->timer (after => 0.05, cb => $rcb); |
|
|
1271 | |
|
|
1272 | bless \\$cb, "AnyEvent::Base::idle" |
|
|
1273 | } |
|
|
1274 | |
|
|
1275 | sub AnyEvent::Base::idle::DESTROY { |
|
|
1276 | undef $${$_[0]}; |
|
|
1277 | } |
|
|
1278 | |
|
|
1279 | package AnyEvent::CondVar; |
|
|
1280 | |
|
|
1281 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
1282 | |
|
|
1283 | package AnyEvent::CondVar::Base; |
|
|
1284 | |
|
|
1285 | use overload |
|
|
1286 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
1287 | fallback => 1; |
|
|
1288 | |
|
|
1289 | sub _send { |
|
|
1290 | # nop |
|
|
1291 | } |
|
|
1292 | |
|
|
1293 | sub send { |
|
|
1294 | my $cv = shift; |
|
|
1295 | $cv->{_ae_sent} = [@_]; |
|
|
1296 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
1297 | $cv->_send; |
|
|
1298 | } |
|
|
1299 | |
|
|
1300 | sub croak { |
|
|
1301 | $_[0]{_ae_croak} = $_[1]; |
|
|
1302 | $_[0]->send; |
|
|
1303 | } |
|
|
1304 | |
|
|
1305 | sub ready { |
|
|
1306 | $_[0]{_ae_sent} |
|
|
1307 | } |
|
|
1308 | |
|
|
1309 | sub _wait { |
|
|
1310 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
1311 | } |
|
|
1312 | |
|
|
1313 | sub recv { |
|
|
1314 | $_[0]->_wait; |
|
|
1315 | |
|
|
1316 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
1317 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
1318 | } |
|
|
1319 | |
|
|
1320 | sub cb { |
|
|
1321 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
1322 | $_[0]{_ae_cb} |
|
|
1323 | } |
|
|
1324 | |
|
|
1325 | sub begin { |
|
|
1326 | ++$_[0]{_ae_counter}; |
|
|
1327 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1328 | } |
|
|
1329 | |
|
|
1330 | sub end { |
|
|
1331 | return if --$_[0]{_ae_counter}; |
|
|
1332 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1333 | } |
|
|
1334 | |
|
|
1335 | # undocumented/compatibility with pre-3.4 |
|
|
1336 | *broadcast = \&send; |
|
|
1337 | *wait = \&_wait; |
|
|
1338 | |
|
|
1339 | =head1 ERROR AND EXCEPTION HANDLING |
|
|
1340 | |
|
|
1341 | In general, AnyEvent does not do any error handling - it relies on the |
|
|
1342 | caller to do that if required. The L<AnyEvent::Strict> module (see also |
|
|
1343 | the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict |
|
|
1344 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
1345 | development. |
|
|
1346 | |
|
|
1347 | As for exception handling (i.e. runtime errors and exceptions thrown while |
|
|
1348 | executing a callback), this is not only highly event-loop specific, but |
|
|
1349 | also not in any way wrapped by this module, as this is the job of the main |
|
|
1350 | program. |
|
|
1351 | |
|
|
1352 | The pure perl event loop simply re-throws the exception (usually |
|
|
1353 | within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<< |
|
|
1354 | $Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and |
|
|
1355 | so on. |
|
|
1356 | |
|
|
1357 | =head1 ENVIRONMENT VARIABLES |
|
|
1358 | |
|
|
1359 | The following environment variables are used by this module or its |
|
|
1360 | submodules. |
|
|
1361 | |
|
|
1362 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1363 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1364 | enabled. |
|
|
1365 | |
|
|
1366 | =over 4 |
|
|
1367 | |
|
|
1368 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
1369 | |
|
|
1370 | By default, AnyEvent will be completely silent except in fatal |
|
|
1371 | conditions. You can set this environment variable to make AnyEvent more |
|
|
1372 | talkative. |
|
|
1373 | |
|
|
1374 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
1375 | conditions, such as not being able to load the event model specified by |
|
|
1376 | C<PERL_ANYEVENT_MODEL>. |
|
|
1377 | |
|
|
1378 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
1379 | model it chooses. |
|
|
1380 | |
|
|
1381 | =item C<PERL_ANYEVENT_STRICT> |
|
|
1382 | |
|
|
1383 | AnyEvent does not do much argument checking by default, as thorough |
|
|
1384 | argument checking is very costly. Setting this variable to a true value |
|
|
1385 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
|
|
1386 | check the arguments passed to most method calls. If it finds any problems, |
|
|
1387 | it will croak. |
|
|
1388 | |
|
|
1389 | In other words, enables "strict" mode. |
|
|
1390 | |
|
|
1391 | Unlike C<use strict>, it is definitely recommended to keep it off in |
|
|
1392 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
|
|
1393 | developing programs can be very useful, however. |
|
|
1394 | |
|
|
1395 | =item C<PERL_ANYEVENT_MODEL> |
|
|
1396 | |
|
|
1397 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
1398 | auto detection and -probing kicks in. It must be a string consisting |
|
|
1399 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
1400 | and the resulting module name is loaded and if the load was successful, |
|
|
1401 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
1402 | auto detection and -probing. |
|
|
1403 | |
|
|
1404 | This functionality might change in future versions. |
|
|
1405 | |
|
|
1406 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
1407 | could start your program like this: |
|
|
1408 | |
|
|
1409 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1410 | |
|
|
1411 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1412 | |
|
|
1413 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1414 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1415 | of auto probing). |
|
|
1416 | |
|
|
1417 | Must be set to a comma-separated list of protocols or address families, |
|
|
1418 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1419 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1420 | list. |
|
|
1421 | |
|
|
1422 | This variable can effectively be used for denial-of-service attacks |
|
|
1423 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1424 | small, as the program has to handle conenction and other failures anyways. |
|
|
1425 | |
|
|
1426 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1427 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1428 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1429 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1430 | IPv6, but prefer IPv6 over IPv4. |
|
|
1431 | |
|
|
1432 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1433 | |
|
|
1434 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1435 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1436 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1437 | default. |
|
|
1438 | |
|
|
1439 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1440 | EDNS0 in its DNS requests. |
|
|
1441 | |
|
|
1442 | =item C<PERL_ANYEVENT_MAX_FORKS> |
|
|
1443 | |
|
|
1444 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
|
|
1445 | will create in parallel. |
|
|
1446 | |
|
|
1447 | =back |
628 | |
1448 | |
629 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1449 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
630 | |
1450 | |
631 | This is an advanced topic that you do not normally need to use AnyEvent in |
1451 | This is an advanced topic that you do not normally need to use AnyEvent in |
632 | a module. This section is only of use to event loop authors who want to |
1452 | a module. This section is only of use to event loop authors who want to |
… | |
… | |
667 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
1487 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
668 | condition variables: code blocking while waiting for a condition will |
1488 | condition variables: code blocking while waiting for a condition will |
669 | C<die>. This still works with most modules/usages, and blocking calls must |
1489 | C<die>. This still works with most modules/usages, and blocking calls must |
670 | not be done in an interactive application, so it makes sense. |
1490 | not be done in an interactive application, so it makes sense. |
671 | |
1491 | |
672 | =head1 ENVIRONMENT VARIABLES |
|
|
673 | |
|
|
674 | The following environment variables are used by this module: |
|
|
675 | |
|
|
676 | =over 4 |
|
|
677 | |
|
|
678 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
679 | |
|
|
680 | By default, AnyEvent will be completely silent except in fatal |
|
|
681 | conditions. You can set this environment variable to make AnyEvent more |
|
|
682 | talkative. |
|
|
683 | |
|
|
684 | When set to C<1> or higher, causes AnyEvent to warn about unexpected |
|
|
685 | conditions, such as not being able to load the event model specified by |
|
|
686 | C<PERL_ANYEVENT_MODEL>. |
|
|
687 | |
|
|
688 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
689 | model it chooses. |
|
|
690 | |
|
|
691 | =item C<PERL_ANYEVENT_MODEL> |
|
|
692 | |
|
|
693 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
694 | autodetection and -probing kicks in. It must be a string consisting |
|
|
695 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
696 | and the resulting module name is loaded and if the load was successful, |
|
|
697 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
698 | autodetection and -probing. |
|
|
699 | |
|
|
700 | This functionality might change in future versions. |
|
|
701 | |
|
|
702 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
703 | could start your program like this: |
|
|
704 | |
|
|
705 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
706 | |
|
|
707 | =back |
|
|
708 | |
|
|
709 | =head1 EXAMPLE PROGRAM |
1492 | =head1 EXAMPLE PROGRAM |
710 | |
1493 | |
711 | The following program uses an IO watcher to read data from STDIN, a timer |
1494 | The following program uses an I/O watcher to read data from STDIN, a timer |
712 | to display a message once per second, and a condition variable to quit the |
1495 | to display a message once per second, and a condition variable to quit the |
713 | program when the user enters quit: |
1496 | program when the user enters quit: |
714 | |
1497 | |
715 | use AnyEvent; |
1498 | use AnyEvent; |
716 | |
1499 | |
… | |
… | |
721 | poll => 'r', |
1504 | poll => 'r', |
722 | cb => sub { |
1505 | cb => sub { |
723 | warn "io event <$_[0]>\n"; # will always output <r> |
1506 | warn "io event <$_[0]>\n"; # will always output <r> |
724 | chomp (my $input = <STDIN>); # read a line |
1507 | chomp (my $input = <STDIN>); # read a line |
725 | warn "read: $input\n"; # output what has been read |
1508 | warn "read: $input\n"; # output what has been read |
726 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1509 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
727 | }, |
1510 | }, |
728 | ); |
1511 | ); |
729 | |
1512 | |
730 | my $time_watcher; # can only be used once |
1513 | my $time_watcher; # can only be used once |
731 | |
1514 | |
… | |
… | |
736 | }); |
1519 | }); |
737 | } |
1520 | } |
738 | |
1521 | |
739 | new_timer; # create first timer |
1522 | new_timer; # create first timer |
740 | |
1523 | |
741 | $cv->wait; # wait until user enters /^q/i |
1524 | $cv->recv; # wait until user enters /^q/i |
742 | |
1525 | |
743 | =head1 REAL-WORLD EXAMPLE |
1526 | =head1 REAL-WORLD EXAMPLE |
744 | |
1527 | |
745 | Consider the L<Net::FCP> module. It features (among others) the following |
1528 | Consider the L<Net::FCP> module. It features (among others) the following |
746 | API calls, which are to freenet what HTTP GET requests are to http: |
1529 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
796 | syswrite $txn->{fh}, $txn->{request} |
1579 | syswrite $txn->{fh}, $txn->{request} |
797 | or die "connection or write error"; |
1580 | or die "connection or write error"; |
798 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1581 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
799 | |
1582 | |
800 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1583 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
801 | result and signals any possible waiters that the request ahs finished: |
1584 | result and signals any possible waiters that the request has finished: |
802 | |
1585 | |
803 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1586 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
804 | |
1587 | |
805 | if (end-of-file or data complete) { |
1588 | if (end-of-file or data complete) { |
806 | $txn->{result} = $txn->{buf}; |
1589 | $txn->{result} = $txn->{buf}; |
807 | $txn->{finished}->broadcast; |
1590 | $txn->{finished}->send; |
808 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1591 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
809 | } |
1592 | } |
810 | |
1593 | |
811 | The C<result> method, finally, just waits for the finished signal (if the |
1594 | The C<result> method, finally, just waits for the finished signal (if the |
812 | request was already finished, it doesn't wait, of course, and returns the |
1595 | request was already finished, it doesn't wait, of course, and returns the |
813 | data: |
1596 | data: |
814 | |
1597 | |
815 | $txn->{finished}->wait; |
1598 | $txn->{finished}->recv; |
816 | return $txn->{result}; |
1599 | return $txn->{result}; |
817 | |
1600 | |
818 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1601 | The actual code goes further and collects all errors (C<die>s, exceptions) |
819 | that occured during request processing. The C<result> method detects |
1602 | that occurred during request processing. The C<result> method detects |
820 | whether an exception as thrown (it is stored inside the $txn object) |
1603 | whether an exception as thrown (it is stored inside the $txn object) |
821 | and just throws the exception, which means connection errors and other |
1604 | and just throws the exception, which means connection errors and other |
822 | problems get reported tot he code that tries to use the result, not in a |
1605 | problems get reported tot he code that tries to use the result, not in a |
823 | random callback. |
1606 | random callback. |
824 | |
1607 | |
… | |
… | |
855 | |
1638 | |
856 | my $quit = AnyEvent->condvar; |
1639 | my $quit = AnyEvent->condvar; |
857 | |
1640 | |
858 | $fcp->txn_client_get ($url)->cb (sub { |
1641 | $fcp->txn_client_get ($url)->cb (sub { |
859 | ... |
1642 | ... |
860 | $quit->broadcast; |
1643 | $quit->send; |
861 | }); |
1644 | }); |
862 | |
1645 | |
863 | $quit->wait; |
1646 | $quit->recv; |
864 | |
1647 | |
865 | |
1648 | |
866 | =head1 BENCHMARK |
1649 | =head1 BENCHMARKS |
867 | |
1650 | |
868 | To give you an idea of the performance and overheads that AnyEvent adds |
1651 | To give you an idea of the performance and overheads that AnyEvent adds |
869 | over the backends directly, here is a benchmark of various supported event |
1652 | over the event loops themselves and to give you an impression of the speed |
870 | models natively and with anyevent. The benchmark creates a lot of timers |
1653 | of various event loops I prepared some benchmarks. |
|
|
1654 | |
|
|
1655 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
|
|
1656 | |
|
|
1657 | Here is a benchmark of various supported event models used natively and |
|
|
1658 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
871 | (with a zero timeout) and io watchers (watching STDOUT, a pty, to become |
1659 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
872 | writable, which it is), lets them fire exactly once and destroys them |
1660 | which it is), lets them fire exactly once and destroys them again. |
873 | again. |
|
|
874 | |
1661 | |
875 | Explanation of the fields: |
1662 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
|
|
1663 | distribution. |
876 | |
1664 | |
|
|
1665 | =head3 Explanation of the columns |
|
|
1666 | |
877 | I<watcher> is the number of event watchers created/destroyed. Sicne |
1667 | I<watcher> is the number of event watchers created/destroyed. Since |
878 | different event models have vastly different performance each backend was |
1668 | different event models feature vastly different performances, each event |
879 | handed a number of watchers so that overall runtime is acceptable and |
1669 | loop was given a number of watchers so that overall runtime is acceptable |
880 | similar to all backends (and keep them from crashing). |
1670 | and similar between tested event loop (and keep them from crashing): Glib |
|
|
1671 | would probably take thousands of years if asked to process the same number |
|
|
1672 | of watchers as EV in this benchmark. |
881 | |
1673 | |
882 | I<bytes> is the number of bytes (as measured by resident set size) used by |
1674 | I<bytes> is the number of bytes (as measured by the resident set size, |
883 | each watcher. |
1675 | RSS) consumed by each watcher. This method of measuring captures both C |
|
|
1676 | and Perl-based overheads. |
884 | |
1677 | |
885 | I<create> is the time, in microseconds, to create a single watcher. |
1678 | I<create> is the time, in microseconds (millionths of seconds), that it |
|
|
1679 | takes to create a single watcher. The callback is a closure shared between |
|
|
1680 | all watchers, to avoid adding memory overhead. That means closure creation |
|
|
1681 | and memory usage is not included in the figures. |
886 | |
1682 | |
887 | I<invoke> is the time, in microseconds, used to invoke a simple callback |
1683 | I<invoke> is the time, in microseconds, used to invoke a simple |
888 | that simply counts down. |
1684 | callback. The callback simply counts down a Perl variable and after it was |
|
|
1685 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
|
|
1686 | signal the end of this phase. |
889 | |
1687 | |
890 | I<destroy> is the time, in microseconds, to destroy a single watcher. |
1688 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
|
|
1689 | watcher. |
891 | |
1690 | |
|
|
1691 | =head3 Results |
|
|
1692 | |
892 | name watcher bytes create invoke destroy comment |
1693 | name watchers bytes create invoke destroy comment |
893 | EV/EV 400000 244 0.56 0.46 0.31 EV native interface |
1694 | EV/EV 400000 224 0.47 0.35 0.27 EV native interface |
894 | EV/Any 100000 610 3.52 0.91 0.75 |
1695 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
895 | CoroEV/Any 100000 610 3.49 0.92 0.75 coroutines + Coro::Signal |
1696 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
896 | Perl/Any 10000 654 4.64 1.22 0.77 pure perl implementation |
1697 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
897 | Event/Event 10000 523 28.05 21.38 5.22 Event native interface |
1698 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
898 | Event/Any 10000 943 34.43 20.48 1.39 |
1699 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
|
|
1700 | IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll |
|
|
1701 | IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll |
899 | Glib/Any 16000 1357 96.99 12.55 55.51 quadratic behaviour |
1702 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
900 | Tk/Any 2000 1855 27.01 66.61 14.03 SEGV with >> 2000 watchers |
1703 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
901 | POE/Select 2000 6343 94.69 807.65 562.69 POE::Loop::Select |
|
|
902 | POE/Event 2000 6644 108.15 768.19 14.33 POE::Loop::Event |
1704 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
|
|
1705 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
903 | |
1706 | |
904 | Discussion: The benchmark does I<not> bench scalability of the |
1707 | =head3 Discussion |
|
|
1708 | |
|
|
1709 | The benchmark does I<not> measure scalability of the event loop very |
905 | backend. For example a select-based backend (such as the pureperl one) can |
1710 | well. For example, a select-based event loop (such as the pure perl one) |
906 | never compete with a backend using epoll. In this benchmark, only a single |
1711 | can never compete with an event loop that uses epoll when the number of |
907 | filehandle is used. |
1712 | file descriptors grows high. In this benchmark, all events become ready at |
|
|
1713 | the same time, so select/poll-based implementations get an unnatural speed |
|
|
1714 | boost. |
908 | |
1715 | |
|
|
1716 | Also, note that the number of watchers usually has a nonlinear effect on |
|
|
1717 | overall speed, that is, creating twice as many watchers doesn't take twice |
|
|
1718 | the time - usually it takes longer. This puts event loops tested with a |
|
|
1719 | higher number of watchers at a disadvantage. |
|
|
1720 | |
|
|
1721 | To put the range of results into perspective, consider that on the |
|
|
1722 | benchmark machine, handling an event takes roughly 1600 CPU cycles with |
|
|
1723 | EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU |
|
|
1724 | cycles with POE. |
|
|
1725 | |
909 | EV is the sole leader regarding speed and memory use, which are both |
1726 | C<EV> is the sole leader regarding speed and memory use, which are both |
910 | maximal/minimal. Even when going through AnyEvent, there is only one event |
1727 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
911 | loop that uses less memory (the Event module natively), and no faster |
1728 | far less memory than any other event loop and is still faster than Event |
912 | event model. |
1729 | natively. |
913 | |
1730 | |
914 | The pure perl implementation is hit in a few sweet spots (both the |
1731 | The pure perl implementation is hit in a few sweet spots (both the |
915 | zero timeout and the use of a single fd hit optimisations in the perl |
1732 | constant timeout and the use of a single fd hit optimisations in the perl |
916 | interpreter and the backend itself), but it shows that it adds very little |
1733 | interpreter and the backend itself). Nevertheless this shows that it |
917 | overhead in itself. Like any select-based backend it's performance becomes |
1734 | adds very little overhead in itself. Like any select-based backend its |
918 | really bad with lots of file descriptors. |
1735 | performance becomes really bad with lots of file descriptors (and few of |
|
|
1736 | them active), of course, but this was not subject of this benchmark. |
919 | |
1737 | |
920 | The Event module has a relatively high setup and callback invocation cost, |
1738 | The C<Event> module has a relatively high setup and callback invocation |
921 | but overall scores on the third place. |
1739 | cost, but overall scores in on the third place. |
922 | |
1740 | |
923 | Glib has a little higher memory cost, a bit fster callback invocation and |
1741 | C<IO::Async> performs admirably well, about on par with C<Event>, even |
924 | has a similar speed as Event. |
1742 | when using its pure perl backend. |
925 | |
1743 | |
|
|
1744 | C<Glib>'s memory usage is quite a bit higher, but it features a |
|
|
1745 | faster callback invocation and overall ends up in the same class as |
|
|
1746 | C<Event>. However, Glib scales extremely badly, doubling the number of |
|
|
1747 | watchers increases the processing time by more than a factor of four, |
|
|
1748 | making it completely unusable when using larger numbers of watchers |
|
|
1749 | (note that only a single file descriptor was used in the benchmark, so |
|
|
1750 | inefficiencies of C<poll> do not account for this). |
|
|
1751 | |
926 | The Tk backend works relatively well, the fact that it crashes with |
1752 | The C<Tk> adaptor works relatively well. The fact that it crashes with |
927 | more than 2000 watchers is a big setback, however, as correctness takes |
1753 | more than 2000 watchers is a big setback, however, as correctness takes |
928 | precedence over speed. |
1754 | precedence over speed. Nevertheless, its performance is surprising, as the |
|
|
1755 | file descriptor is dup()ed for each watcher. This shows that the dup() |
|
|
1756 | employed by some adaptors is not a big performance issue (it does incur a |
|
|
1757 | hidden memory cost inside the kernel which is not reflected in the figures |
|
|
1758 | above). |
929 | |
1759 | |
930 | POE, regardless of backend (wether it's pure perl select backend or the |
1760 | C<POE>, regardless of underlying event loop (whether using its pure perl |
931 | Event backend) shows abysmal performance and memory usage: Watchers use |
1761 | select-based backend or the Event module, the POE-EV backend couldn't |
932 | almost 30 times as much memory as EV watchers, and 10 times as much memory |
1762 | be tested because it wasn't working) shows abysmal performance and |
933 | as both Event or EV via AnyEvent. |
1763 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
|
|
1764 | as EV watchers, and 10 times as much memory as Event (the high memory |
|
|
1765 | requirements are caused by requiring a session for each watcher). Watcher |
|
|
1766 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1767 | implementation. |
934 | |
1768 | |
|
|
1769 | The design of the POE adaptor class in AnyEvent can not really account |
|
|
1770 | for the performance issues, though, as session creation overhead is |
|
|
1771 | small compared to execution of the state machine, which is coded pretty |
|
|
1772 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1773 | using multiple sessions is not a good approach, especially regarding |
|
|
1774 | memory usage, even the author of POE could not come up with a faster |
|
|
1775 | design). |
|
|
1776 | |
|
|
1777 | =head3 Summary |
|
|
1778 | |
|
|
1779 | =over 4 |
|
|
1780 | |
935 | Summary: using EV through AnyEvent is faster than any other event |
1781 | =item * Using EV through AnyEvent is faster than any other event loop |
936 | loop. The overhead AnyEvent adds can be very small, and you should avoid |
1782 | (even when used without AnyEvent), but most event loops have acceptable |
937 | POE like the plague if you want performance or reasonable memory usage. |
1783 | performance with or without AnyEvent. |
938 | |
1784 | |
|
|
1785 | =item * The overhead AnyEvent adds is usually much smaller than the overhead of |
|
|
1786 | the actual event loop, only with extremely fast event loops such as EV |
|
|
1787 | adds AnyEvent significant overhead. |
|
|
1788 | |
|
|
1789 | =item * You should avoid POE like the plague if you want performance or |
|
|
1790 | reasonable memory usage. |
|
|
1791 | |
|
|
1792 | =back |
|
|
1793 | |
|
|
1794 | =head2 BENCHMARKING THE LARGE SERVER CASE |
|
|
1795 | |
|
|
1796 | This benchmark actually benchmarks the event loop itself. It works by |
|
|
1797 | creating a number of "servers": each server consists of a socket pair, a |
|
|
1798 | timeout watcher that gets reset on activity (but never fires), and an I/O |
|
|
1799 | watcher waiting for input on one side of the socket. Each time the socket |
|
|
1800 | watcher reads a byte it will write that byte to a random other "server". |
|
|
1801 | |
|
|
1802 | The effect is that there will be a lot of I/O watchers, only part of which |
|
|
1803 | are active at any one point (so there is a constant number of active |
|
|
1804 | fds for each loop iteration, but which fds these are is random). The |
|
|
1805 | timeout is reset each time something is read because that reflects how |
|
|
1806 | most timeouts work (and puts extra pressure on the event loops). |
|
|
1807 | |
|
|
1808 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
|
|
1809 | (1%) are active. This mirrors the activity of large servers with many |
|
|
1810 | connections, most of which are idle at any one point in time. |
|
|
1811 | |
|
|
1812 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
|
|
1813 | distribution. |
|
|
1814 | |
|
|
1815 | =head3 Explanation of the columns |
|
|
1816 | |
|
|
1817 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
|
|
1818 | each server has a read and write socket end). |
|
|
1819 | |
|
|
1820 | I<create> is the time it takes to create a socket pair (which is |
|
|
1821 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
|
|
1822 | |
|
|
1823 | I<request>, the most important value, is the time it takes to handle a |
|
|
1824 | single "request", that is, reading the token from the pipe and forwarding |
|
|
1825 | it to another server. This includes deleting the old timeout and creating |
|
|
1826 | a new one that moves the timeout into the future. |
|
|
1827 | |
|
|
1828 | =head3 Results |
|
|
1829 | |
|
|
1830 | name sockets create request |
|
|
1831 | EV 20000 69.01 11.16 |
|
|
1832 | Perl 20000 73.32 35.87 |
|
|
1833 | IOAsync 20000 157.00 98.14 epoll |
|
|
1834 | IOAsync 20000 159.31 616.06 poll |
|
|
1835 | Event 20000 212.62 257.32 |
|
|
1836 | Glib 20000 651.16 1896.30 |
|
|
1837 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
|
|
1838 | |
|
|
1839 | =head3 Discussion |
|
|
1840 | |
|
|
1841 | This benchmark I<does> measure scalability and overall performance of the |
|
|
1842 | particular event loop. |
|
|
1843 | |
|
|
1844 | EV is again fastest. Since it is using epoll on my system, the setup time |
|
|
1845 | is relatively high, though. |
|
|
1846 | |
|
|
1847 | Perl surprisingly comes second. It is much faster than the C-based event |
|
|
1848 | loops Event and Glib. |
|
|
1849 | |
|
|
1850 | IO::Async performs very well when using its epoll backend, and still quite |
|
|
1851 | good compared to Glib when using its pure perl backend. |
|
|
1852 | |
|
|
1853 | Event suffers from high setup time as well (look at its code and you will |
|
|
1854 | understand why). Callback invocation also has a high overhead compared to |
|
|
1855 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
|
|
1856 | uses select or poll in basically all documented configurations. |
|
|
1857 | |
|
|
1858 | Glib is hit hard by its quadratic behaviour w.r.t. many watchers. It |
|
|
1859 | clearly fails to perform with many filehandles or in busy servers. |
|
|
1860 | |
|
|
1861 | POE is still completely out of the picture, taking over 1000 times as long |
|
|
1862 | as EV, and over 100 times as long as the Perl implementation, even though |
|
|
1863 | it uses a C-based event loop in this case. |
|
|
1864 | |
|
|
1865 | =head3 Summary |
|
|
1866 | |
|
|
1867 | =over 4 |
|
|
1868 | |
|
|
1869 | =item * The pure perl implementation performs extremely well. |
|
|
1870 | |
|
|
1871 | =item * Avoid Glib or POE in large projects where performance matters. |
|
|
1872 | |
|
|
1873 | =back |
|
|
1874 | |
|
|
1875 | =head2 BENCHMARKING SMALL SERVERS |
|
|
1876 | |
|
|
1877 | While event loops should scale (and select-based ones do not...) even to |
|
|
1878 | large servers, most programs we (or I :) actually write have only a few |
|
|
1879 | I/O watchers. |
|
|
1880 | |
|
|
1881 | In this benchmark, I use the same benchmark program as in the large server |
|
|
1882 | case, but it uses only eight "servers", of which three are active at any |
|
|
1883 | one time. This should reflect performance for a small server relatively |
|
|
1884 | well. |
|
|
1885 | |
|
|
1886 | The columns are identical to the previous table. |
|
|
1887 | |
|
|
1888 | =head3 Results |
|
|
1889 | |
|
|
1890 | name sockets create request |
|
|
1891 | EV 16 20.00 6.54 |
|
|
1892 | Perl 16 25.75 12.62 |
|
|
1893 | Event 16 81.27 35.86 |
|
|
1894 | Glib 16 32.63 15.48 |
|
|
1895 | POE 16 261.87 276.28 uses POE::Loop::Event |
|
|
1896 | |
|
|
1897 | =head3 Discussion |
|
|
1898 | |
|
|
1899 | The benchmark tries to test the performance of a typical small |
|
|
1900 | server. While knowing how various event loops perform is interesting, keep |
|
|
1901 | in mind that their overhead in this case is usually not as important, due |
|
|
1902 | to the small absolute number of watchers (that is, you need efficiency and |
|
|
1903 | speed most when you have lots of watchers, not when you only have a few of |
|
|
1904 | them). |
|
|
1905 | |
|
|
1906 | EV is again fastest. |
|
|
1907 | |
|
|
1908 | Perl again comes second. It is noticeably faster than the C-based event |
|
|
1909 | loops Event and Glib, although the difference is too small to really |
|
|
1910 | matter. |
|
|
1911 | |
|
|
1912 | POE also performs much better in this case, but is is still far behind the |
|
|
1913 | others. |
|
|
1914 | |
|
|
1915 | =head3 Summary |
|
|
1916 | |
|
|
1917 | =over 4 |
|
|
1918 | |
|
|
1919 | =item * C-based event loops perform very well with small number of |
|
|
1920 | watchers, as the management overhead dominates. |
|
|
1921 | |
|
|
1922 | =back |
|
|
1923 | |
|
|
1924 | =head2 THE IO::Lambda BENCHMARK |
|
|
1925 | |
|
|
1926 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1927 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
1928 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
1929 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
1930 | fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't |
|
|
1931 | very optimal. But how would AnyEvent compare when used without the extra |
|
|
1932 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
1933 | |
|
|
1934 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
1935 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
1936 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
1937 | test the efficiency of the framework or much non-blocking I/O, but it is a |
|
|
1938 | benchmark nevertheless. |
|
|
1939 | |
|
|
1940 | name runtime |
|
|
1941 | Lambda/select 0.330 sec |
|
|
1942 | + optimized 0.122 sec |
|
|
1943 | Lambda/AnyEvent 0.327 sec |
|
|
1944 | + optimized 0.138 sec |
|
|
1945 | Raw sockets/select 0.077 sec |
|
|
1946 | POE/select, components 0.662 sec |
|
|
1947 | POE/select, raw sockets 0.226 sec |
|
|
1948 | POE/select, optimized 0.404 sec |
|
|
1949 | |
|
|
1950 | AnyEvent/select/nb 0.085 sec |
|
|
1951 | AnyEvent/EV/nb 0.068 sec |
|
|
1952 | +state machine 0.134 sec |
|
|
1953 | |
|
|
1954 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
1955 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
1956 | defeating the purpose of an event-based solution. All of the newly |
|
|
1957 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
1958 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
1959 | resolver), so AnyEvent is at a disadvantage here, as non-blocking connects |
|
|
1960 | generally require a lot more bookkeeping and event handling than blocking |
|
|
1961 | connects (which involve a single syscall only). |
|
|
1962 | |
|
|
1963 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
1964 | offers similar expressive power as POE and IO::Lambda, using conventional |
|
|
1965 | Perl syntax. This means that both the echo server and the client are 100% |
|
|
1966 | non-blocking, further placing it at a disadvantage. |
|
|
1967 | |
|
|
1968 | As you can see, the AnyEvent + EV combination even beats the |
|
|
1969 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
1970 | backend easily beats IO::Lambda and POE. |
|
|
1971 | |
|
|
1972 | And even the 100% non-blocking version written using the high-level (and |
|
|
1973 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a |
|
|
1974 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
|
|
1975 | in a non-blocking way. |
|
|
1976 | |
|
|
1977 | The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and |
|
|
1978 | F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are |
|
|
1979 | part of the IO::lambda distribution and were used without any changes. |
|
|
1980 | |
|
|
1981 | |
|
|
1982 | =head1 SIGNALS |
|
|
1983 | |
|
|
1984 | AnyEvent currently installs handlers for these signals: |
|
|
1985 | |
|
|
1986 | =over 4 |
|
|
1987 | |
|
|
1988 | =item SIGCHLD |
|
|
1989 | |
|
|
1990 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
|
|
1991 | emulation for event loops that do not support them natively. Also, some |
|
|
1992 | event loops install a similar handler. |
|
|
1993 | |
|
|
1994 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will |
|
|
1995 | reset it to default, to avoid losing child exit statuses. |
|
|
1996 | |
|
|
1997 | =item SIGPIPE |
|
|
1998 | |
|
|
1999 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
|
|
2000 | when AnyEvent gets loaded. |
|
|
2001 | |
|
|
2002 | The rationale for this is that AnyEvent users usually do not really depend |
|
|
2003 | on SIGPIPE delivery (which is purely an optimisation for shell use, or |
|
|
2004 | badly-written programs), but C<SIGPIPE> can cause spurious and rare |
|
|
2005 | program exits as a lot of people do not expect C<SIGPIPE> when writing to |
|
|
2006 | some random socket. |
|
|
2007 | |
|
|
2008 | The rationale for installing a no-op handler as opposed to ignoring it is |
|
|
2009 | that this way, the handler will be restored to defaults on exec. |
|
|
2010 | |
|
|
2011 | Feel free to install your own handler, or reset it to defaults. |
|
|
2012 | |
|
|
2013 | =back |
|
|
2014 | |
|
|
2015 | =cut |
|
|
2016 | |
|
|
2017 | undef $SIG{CHLD} |
|
|
2018 | if $SIG{CHLD} eq 'IGNORE'; |
|
|
2019 | |
|
|
2020 | $SIG{PIPE} = sub { } |
|
|
2021 | unless defined $SIG{PIPE}; |
939 | |
2022 | |
940 | =head1 FORK |
2023 | =head1 FORK |
941 | |
2024 | |
942 | Most event libraries are not fork-safe. The ones who are usually are |
2025 | Most event libraries are not fork-safe. The ones who are usually are |
943 | because they are so inefficient. Only L<EV> is fully fork-aware. |
2026 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
2027 | calls. Only L<EV> is fully fork-aware. |
944 | |
2028 | |
945 | If you have to fork, you must either do so I<before> creating your first |
2029 | If you have to fork, you must either do so I<before> creating your first |
946 | watcher OR you must not use AnyEvent at all in the child. |
2030 | watcher OR you must not use AnyEvent at all in the child. |
947 | |
2031 | |
948 | |
2032 | |
… | |
… | |
956 | specified in the variable. |
2040 | specified in the variable. |
957 | |
2041 | |
958 | You can make AnyEvent completely ignore this variable by deleting it |
2042 | You can make AnyEvent completely ignore this variable by deleting it |
959 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
2043 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
960 | |
2044 | |
961 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
2045 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
962 | |
2046 | |
963 | use AnyEvent; |
2047 | use AnyEvent; |
|
|
2048 | |
|
|
2049 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
2050 | be used to probe what backend is used and gain other information (which is |
|
|
2051 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
|
|
2052 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2053 | |
|
|
2054 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
2055 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
2056 | enabled. |
|
|
2057 | |
|
|
2058 | |
|
|
2059 | =head1 BUGS |
|
|
2060 | |
|
|
2061 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
|
|
2062 | to work around. If you suffer from memleaks, first upgrade to Perl 5.10 |
|
|
2063 | and check wether the leaks still show up. (Perl 5.10.0 has other annoying |
|
|
2064 | memleaks, such as leaking on C<map> and C<grep> but it is usually not as |
|
|
2065 | pronounced). |
964 | |
2066 | |
965 | |
2067 | |
966 | =head1 SEE ALSO |
2068 | =head1 SEE ALSO |
967 | |
2069 | |
968 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
2070 | Utility functions: L<AnyEvent::Util>. |
969 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
2071 | |
|
|
2072 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
970 | L<Event::Lib>, L<Qt>, L<POE>. |
2073 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
971 | |
2074 | |
972 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
2075 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
973 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
2076 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
974 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
2077 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
975 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
2078 | L<AnyEvent::Impl::POE>. |
976 | |
2079 | |
|
|
2080 | Non-blocking file handles, sockets, TCP clients and |
|
|
2081 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
2082 | |
|
|
2083 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
2084 | |
|
|
2085 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
2086 | |
977 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
2087 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
978 | |
2088 | |
979 | |
2089 | |
980 | =head1 AUTHOR |
2090 | =head1 AUTHOR |
981 | |
2091 | |
982 | Marc Lehmann <schmorp@schmorp.de> |
2092 | Marc Lehmann <schmorp@schmorp.de> |
983 | http://home.schmorp.de/ |
2093 | http://home.schmorp.de/ |
984 | |
2094 | |
985 | =cut |
2095 | =cut |
986 | |
2096 | |
987 | 1 |
2097 | 1 |
988 | |
2098 | |