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Comparing AnyEvent-Watchdog/Watchdog.pm (file contents):
Revision 1.1 by root, Sun Aug 2 14:51:29 2009 UTC vs.
Revision 1.8 by root, Wed Oct 24 17:05:33 2012 UTC

… …
2 2
3AnyEvent::Watchdog - generic watchdog/program restarter 3AnyEvent::Watchdog - generic watchdog/program restarter
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 # MUST be use'd as the very first thing in the main program 7 # MUST be use'd as the very first thing in the main program,
8 # as it clones/forks the program before it returns.
8 use AnyEvent::Watchdog; 9 use AnyEvent::Watchdog;
9 10
10=head1 DESCRIPTION 11=head1 DESCRIPTION
11 12
12This module implements a watchdog that can repeatedly fork the program and 13This module implements a watchdog that can repeatedly fork the program and
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21program. It will cause weird effects when used from another module, as 22program. It will cause weird effects when used from another module, as
22perl does not expect to be forked inside C<BEGIN> blocks. 23perl does not expect to be forked inside C<BEGIN> blocks.
23 24
24=head1 RECIPES 25=head1 RECIPES
25 26
26Use AnyEvent::Watchdog solely as a convinient on-demand-restarter: 27Use AnyEvent::Watchdog solely as a convenient on-demand-restarter:
27 28
28 use AnyEvent::Watchdog; 29 use AnyEvent::Watchdog;
29 30
30 # and whenever you wnat to restart (e.g. to upgrade code): 31 # and whenever you want to restart (e.g. to upgrade code):
32 use AnyEvent::Watchdog::Util;
31 AnyEvent::Watchdog::restart; 33 AnyEvent::Watchdog::Util::restart;
32 34
33Use AnyEvent::Watchdog to kill the program and exit when the event loop 35Use AnyEvent::Watchdog to kill the program and exit when the event loop
34fails to run for more than two minutes: 36fails to run for more than two minutes:
35 37
36 use AnyEvent::Watchdog qw(autorestart heartbeat=120); 38 use AnyEvent::Watchdog autorestart => 1, heartbeat => 120;
37 39
38Use AnyEvent::Watchdog to automatically restart the program 40Use AnyEvent::Watchdog to automatically kill (but not restart) the program when it fails
39when it fails to handle events for longer than 5 minutes: 41to handle events for longer than 5 minutes:
40 42
41 use AnyEvent::Watchdog qw(autorestart heartbeat=300); 43 use AnyEvent::Watchdog heartbeat => 300;
42 44
43=head1 FUNCTIONS 45=head1 VARIABLES/FUNCTIONS
44 46
45The module supports the following functions: 47This module is controlled via the L<AnyEvent::Watchdog::Util> module:
46 48
47=over 4 49 use AnyEvent::Watchdog::Util;
50
51 # attempt restart
52 AnyEvent::Watchdog::Util::restart;
53
54 # check if it is running
55 AnyEvent::Watchdog::Util::enabled
56 or croak "not running under watchdog!";
48 57
49=cut 58=cut
50 59
51package AnyEvent::Watchdog; 60package AnyEvent::Watchdog;
52 61
53# load modules we will use later anyways 62# load modules we will use later anyways
54use common::sense; 63use common::sense;
55 64
56use Carp (); 65use Carp ();
57 66
58our $VERSION = '0.1'; 67our $VERSION = '1.0';
59 68
60our $PID; # child pid 69our $PID; # child pid
61our $ENABLED = 1; 70our $ENABLED = 0; # also version
62our $AUTORESTART; # actually exit 71our $AUTORESTART; # actually exit
63our $HEARTBEAT;
64our ($P, $C); 72our ($P, $C);
65 73
66sub poll($) { 74sub poll($) {
67 (vec my $v, fileno $P, 1) = 1; 75 (vec my $v, fileno $P, 1) = 1;
68 CORE::select $v, undef, undef, $_[0] 76 CORE::select $v, undef, undef, $_[0]
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118 126
119 } elsif ($cmd eq chr 3) { 127 } elsif ($cmd eq chr 3) {
120 sysread $P, my $interval, 1 128 sysread $P, my $interval, 1
121 or last; 129 or last;
122 130
123 $heartbeat = ord $interval 131 $heartbeat = ord $interval;
124 unless defined $heartbeat;
125 132
126 } elsif ($cmd eq chr 4) { 133 } elsif ($cmd eq chr 4) {
127 # heartbeat 134 # heartbeat
128 # TODO: should only reset heartbeat timeout with \005 135 # TODO: should only reset heartbeat timeout with \005
129 136
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165 172
166our %SEEKPOS; 173our %SEEKPOS;
167# due to bugs in perl, try to remember file offsets for all fds, and restore them later 174# due to bugs in perl, try to remember file offsets for all fds, and restore them later
168# (the parser otherwise exhausts the input files) 175# (the parser otherwise exhausts the input files)
169 176
170# this causes perlio to flush it's handles internally, so 177# this causes perlio to flush its handles internally, so
171# seek offsets become correct. 178# seek offsets become correct.
172exec "."; # toi toi toi 179exec "."; # toi toi toi
173#{ 180#{
174# local $SIG{CHLD} = 'DEFAULT'; 181# local $SIG{CHLD} = 'DEFAULT';
175# my $pid = fork; 182# my $pid = fork;
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179# } else { 186# } else {
180# kill 9, $$; 187# kill 9, $$;
181# } 188# }
182#} 189#}
183 190
184# now records all fd positions 191# now record "all" fd positions, assuming 1023 is more than enough.
185for (0 .. 1023) { 192for (0 .. 1023) {
186 open my $fh, "<&$_" or next; 193 open my $fh, "<&$_" or next;
187 $SEEKPOS{$_} = (sysseek $fh, 0, 1 or next); 194 $SEEKPOS{$_} = (sysseek $fh, 0, 1 or next);
188} 195}
189 196
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204 211
205 unless (defined $PID) { 212 unless (defined $PID) {
206 warn "AnyEvent::Watchdog: '$!', retrying in one second...\n"; 213 warn "AnyEvent::Watchdog: '$!', retrying in one second...\n";
207 sleep 1; 214 sleep 1;
208 } elsif ($PID) { 215 } elsif ($PID) {
216 # parent code
209 close $C; 217 close $C;
210 server; 218 server;
211 } else { 219 } else {
220 # child code
221 $ENABLED = 1; # also version
222
212 # restore seek offsets 223 # restore seek offsets
213 while (my ($k, $v) = each %SEEKPOS) { 224 while (my ($k, $v) = each %SEEKPOS) {
214 open my $fh, "<&$k" or next; 225 open my $fh, "<&$k" or next;
215 sysseek $fh, $v, 0; 226 sysseek $fh, $v, 0;
216 } 227 }
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219 close $P; 230 close $P;
220 last; 231 last;
221 } 232 }
222} 233}
223 234
224=item AnyEvent::Watchdog::restart [$timeout]
225
226Tells the supervisor to restart the process when it exits, or forcefully
227after C<$timeout> seconds (minimum 1, maximum 255, default 60).
228
229Calls C<exit 0> to exit the process cleanly.
230
231=cut
232
233sub restart(;$) {
234 my ($timeout) = @_;
235
236 $timeout = 60 unless defined $timeout;
237 $timeout = 1 if $timeout < 1;
238 $timeout = 255 if $timeout > 255;
239
240 syswrite $C, "\x01\x02" . chr $timeout;
241 exit 0;
242}
243
244=item AnyEvent::Watchdog::autorestart [$boolean]
245
246=item use AnyEvent::Watchdog qw(autorestart[=$boolean])
247
248Enables or disables autorestart (initially disabled, default for
249C<$boolean> is to enable): By default, the supervisor will exit if the
250program exits or dies in any way. When enabling autorestart behaviour,
251then the supervisor will try to restart the program after it dies.
252
253Note that the supervisor will never autorestart when the child died with
254SIGINT or SIGTERM.
255
256=cut
257
258sub autorestart(;$) {
259 syswrite $C, !@_ || $_[0] ? "\x01" : "\x00";
260}
261
262=item AnyEvent::Watchdog::heartbeat [$interval]
263
264=item use AnyEvent::Watchdog qw(heartbeat[=$interval])
265
266Tells the supervisor to automatically kill the program if it doesn't
267react for C<$interval> seconds (minium 1, maximum 255, default 60) , then
268installs an AnyEvent timer the sends a regular heartbeat to the supervisor
269twice as often.
270
271Exit behaviour isn't changed, so if you want a restart instead of an exit,
272you have to call C<autorestart>.
273
274Once enabled, the heartbeat cannot be switched off.
275
276=cut
277
278sub heartbeat(;$) {
279 my ($interval) = @_;
280
281 $interval = 60 unless defined $interval;
282 $interval = 1 if $interval < 1;
283 $interval = 255 if $interval > 255;
284
285 syswrite $C, "\x03" . chr $interval;
286
287 require AE;
288 $HEARTBEAT = AE::timer (0, $interval * 0.5, sub {
289 syswrite $C, "\x04";
290 });
291}
292
293sub import { 235sub import {
294 shift; 236 shift;
295 237
296 for (@_) { 238 while (@_) {
297 if (/^autorestart(?:=(.*))?$/) { 239 my $k = shift;
298 autorestart defined $1 ? $1 : 1; 240
299 } elsif (/^heartbeat(?:=(.*))?$/) { 241 require AnyEvent::Watchdog::Util;
300 heartbeat $1; 242
243 if ($k eq "autorestart") {
244 AnyEvent::Watchdog::Util::autorestart (! ! shift);
245 } elsif ($k eq "heartbeat") {
246 AnyEvent::Watchdog::Util::heartbeat (shift || 60);
301 } else { 247 } else {
302 Carp::croak "AnyEvent::Watchdog: '$_' is not a valid import argument"; 248 Carp::croak "AnyEvent::Watchdog: '$_' is not a valid import argument";
303 } 249 }
304 } 250 }
305} 251}
306 252
253# used by AnyEvent::Watchdog::Util.
254our $end;
255END { $end && &$end }
256
307=head1 SEE ALSO 257=head1 SEE ALSO
308 258
309L<AnyEvent>. 259L<AnyEvent::Watchdog::Util>, L<AnyEvent>.
310 260
311=head1 AUTHOR 261=head1 AUTHOR
312 262
313 Marc Lehmann <schmorp@schmorp.de> 263 Marc Lehmann <schmorp@schmorp.de>
314 http://home.schmorp.de/ 264 http://home.schmorp.de/

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