This file is indexed.

/usr/share/perl5/App/Inotify/Hookable.pm is in inotify-hookable 0.09-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
#!/usr/bin/env perl
package App::Inotify::Hookable;
BEGIN {
  $App::Inotify::Hookable::AUTHORITY = 'cpan:AVAR';
}
{
  $App::Inotify::Hookable::VERSION = '0.09';
}
use Moose;
use MooseX::Types::Moose ':all';
use Linux::Inotify2;
use POSIX ':errno_h';
use Time::HiRes qw(gettimeofday tv_interval ualarm);
use Try::Tiny;
use Data::BitMask;
use Data::Dumper;
use Class::Inspector;
use List::MoreUtils qw(uniq);

with 'MooseX::Getopt::Dashes';

has debug => (
    metaclass      => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => Bool,
    default       => 0,
    cmd_aliases   => 'd',
    documentation => "Should we print debug info about what we're doing?",
);

has quiet => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => Bool,
    default       => 0,
    cmd_aliases   => 'q',
    documentation => q{Don't log noisy information},
);

has watch_directories => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => ArrayRef[Str],
    default       => sub { [] },
    cmd_aliases   => 'w',
    auto_deref    => 1,
    documentation => "What directories should we watch?",
);

has watch_files => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => ArrayRef[Str],
    default       => sub { [] },
    cmd_aliases   => 'f',
    auto_deref    => 1,
    documentation => "What files should we watch?",
);

has recursive => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => Bool,
    default       => 1,
    cmd_aliases   => 'r',
    documentation => "Should we recursively watch the directories we're watching? On by default.",
);

has on_modify_command => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => ArrayRef[Str],
    default       => sub { [] },
    auto_deref    => 1,
    cmd_aliases   => 'c',
    documentation => "What commands should we run when something happens?",
);

has on_modify_path_command => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => HashRef[Str],
    default       => sub { +{} },
    cmd_aliases   => 'C',
    documentation => "What commands should we run for a given path when something happens? The key is a regex and the value is a command.",
);

has buffer_time => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => Int,
    default       => 100,
    cmd_aliases   => 't',
    documentation => "How many milliseconds should we buffer inotify for? (default 100)",
);

has ignore_paths => (
    metaclass     => 'MooseX::Getopt::Meta::Attribute',
    is            => 'ro',
    isa           => ArrayRef[Str],
    default       => sub { [ '\..*sw.\z', '\.\#[^/]+\z' ] },
    cmd_aliases   => 'i',
    auto_deref    => 1,
    documentation => q|Regexes for which paths we should ignore (default '\..*sw.\z' and '\.\#[^/]+\z' for vim and emacs swap files.)|
);

has _watches => (
    is            => 'ro',
    isa           => HashRef,
    default       => sub { +{} },
    documentation => "What stuff are we watching?",
);

has _notifier => (
    is         => 'rw',
    isa        => 'Linux::Inotify2',
    lazy_build => 1,
);

has _bitmask => (
    is         => 'rw',
    isa        => 'Data::BitMask',
    lazy_build => 1,
);

has _previously_watched_directories => (
    is         => 'rw',
    isa        => ArrayRef[Str],
);

sub _build__notifier { Linux::Inotify2->new }

sub log {
    my ($self, $message) = @_;
    return if $self->quiet;
    print STDERR scalar(localtime()), " : ", $message, "\n";
};

my $dumper_squashed = sub {
    my $val = shift;

    my $dd = Data::Dumper->new([]);
    $dd->Terse(1)->Indent(1)->Useqq(1)->Deparse(1)->Quotekeys(0)->Sortkeys(1)->Indent(0);
    return $dd->Values([ $val ])->Dump;
};

sub run {
    my ($self) = @_;

    # Catch sigint so DEMOLISH can run
    local $SIG{INT} = sub { exit 1 };

    my @watch_dirs  = $self->watch_directories;
    my @watch_files = $self->watch_files;
    die "You need to give me something to watch" unless @watch_dirs || @watch_files;
    $self->log(
        "Starting up, " .
        (@watch_dirs ?
            ($self->recursive ? "recursively" : "non-recursively") .
            " " .
            "watching directories <@watch_dirs>" .
            (@watch_files ? " and " : "")
        : "") .
        (@watch_files ?
            "watching files <@watch_files>"
        : "")
    );

    my $notifier = $self->_notifier;
    $self->setup_watch;
    my $buffer_time = $self->buffer_time;
    while (my @events = $notifier->read()) {
        # At this point we have an event, but Linux sends these *really
        # fast* so if someone does "touch foo bar zar" we might only get
        # an event for the first file, then later the rest.
        #
        # So buffer up events for $sleep_ms and see if we stop getting
        # them, then restart.
        my $sleep_ms = $buffer_time;
        my $sleep_us = $sleep_ms * 10**3;

        my %modified_paths;

        my $log_modified_paths = sub {
            my $events = shift;
            for my $event (@$events) {
                my $fullname = $event->fullname;
                $fullname =~ s[//][/]g; # We have double slashes for some reason

                my $ignore_path = 0;

                IGNORE_PATHS: foreach my $re ($self->ignore_paths) {
                    if ($fullname =~ m{(?:/|^)$re}) {
                        $ignore_path = 1;
                        last IGNORE_PATHS;
                    }
                }

                $modified_paths{$fullname} = undef if not $ignore_path;
            }
            return;
        };

      WAIT: while (1) {
            for my $event (@events) {
                $self->log("EVENT: " . $dumper_squashed->({
                    cookie => $event->cookie,
                    fullname => $event->fullname,
                    mask => $self->_bitmask->explain_mask($event->mask),
                })) if $self->debug;
            }
            $log_modified_paths->(\@events);
            @events = ();
            try {
                local $SIG{ALRM} = sub {
                    die "Timeout waiting for ->read";
                };
                ualarm($sleep_us);
                @events = $notifier->read;
                ualarm(0);
            } catch {
                $self->log("We have no more events with a timeout of $sleep_ms ms") if $self->debug;
            };

            if (@events) {
                $self->log("We have events, waiting another $sleep_ms ms and checking again") if $self->debug;

                $log_modified_paths->(\@events);
            } else {
                # No more events
                last WAIT;
            }
        }

        if (keys %modified_paths) {
            $self->log("Had changes in your paths");

            if (keys %{ $self->on_modify_path_command }) {
                $self->log("Checking for path-specific hooks") if $self->debug;
                my %hooks_to_run;
                my $on_modify_path_command = $self->on_modify_path_command;
                for my $path (keys %modified_paths) {
                    for my $path_hook (keys %$on_modify_path_command) {
                        $hooks_to_run{$path_hook} = 1
                            if $path =~ /$path_hook/;
                    }
                }
                if (keys %hooks_to_run) {
                    $self->log("Running path-specific hooks");
                    my $t0 = [gettimeofday];
                    for my $hook_to_run (keys %hooks_to_run) {
                        my $command = $on_modify_path_command->{$hook_to_run};
                        $self->log("Running path hook <$hook_to_run>: <$command>");
                        system $command;
                    }
                    my $elapsed = tv_interval ( $t0 );
                    $self->log(sprintf "FINISHED running path-specific hooks. Took %.2fs", $elapsed);
                }
            }

            if (my @commands = $self->on_modify_command) {
                $self->log("Running global hooks");
                my $t0 = [gettimeofday];
                for my $command (@commands) {
                    $self->log("Running <$command>");
                    system $command;
                }
                my $elapsed = tv_interval ( $t0 );
                $self->log(sprintf "FINISHED on-modify command. Took %.2fs", $elapsed);
            }
        }

        # Re-setup the watching if needed, we may have new directories.
        $self->setup_watch;
    }

    return 1;
}

sub all_paths_to_watch {
    my ($self) = @_;
    my @watch_directories = $self->watch_directories;
    my @watch_files       = $self->watch_files;
    my @directories;
    if (@watch_directories) {
        if ($self->recursive) {
            chomp(@directories = qx[find @watch_directories -type d]);
        } else {
            @directories = @watch_directories;
        }
    }

    return (
        @watch_files,
        grep {
            # Don't notify on "git status" (creates a lock) and other similar
            # operations.
            not m[
                    (?:
                       # The .git directory
                       /\.git\z
                      |
                       # Something in the .git directory
                       /\.git/
                     )
            ]x
        } @directories
    );
}

sub setup_watch {
    my ($self) = @_;

    my $t0 = [gettimeofday];

    my $notifier = $self->_notifier;
    my $watches  = $self->_watches;
    my $debug    = $self->debug;

    my $watches_added    = 0;
    my $watches_removed  = 0;
    my $watches_replaced = 0;

    my $previously_watched_directories = $self->_previously_watched_directories;
    my @previously_watched_directories = $previously_watched_directories ? @$previously_watched_directories : ();
    my @current_paths_to_watch         = $self->all_paths_to_watch;

    my @all_paths_to_watch = uniq(
        # The stuff we're watching now
        @current_paths_to_watch,
        # what we were watching earlier, so we know to remove watches
        # for that if they've been removed.
        @previously_watched_directories,
    );

    # Add or re-setup watches
    WATCH: for my $path (@all_paths_to_watch) {
        my $have_watch   = exists $watches->{$path};
        my $type         = -d $path ? 'directory' : 'file';
        my $path_exists  = -e $path;
        my $inode_number; $inode_number = (stat $path)[1] if $path_exists;

        # path has gone away
        if ($have_watch && (not $path_exists)) {
            $watches->{$path}{watch}->cancel;
            my $type = $watches->{$path}{type}; # In this case we care what it *was*
            delete $watches->{$path};
            $self->log("$type '$path' has gone away, removing watch") if $debug;
            $watches_removed++;
            next WATCH;
        }

        if ($have_watch) {
            if ($watches->{$path}{inode} eq $inode_number) {
                # We have this watch already, and it hasn't changed the
                # inode number, so no need to go and add it again.
                next WATCH;
            } else {
                # object got replaced, remove the watch (we'll add a
                # new watch for the new object).
                $watches->{$path}{watch}->cancel;
                my $type = $watches->{$path}{type}; # In this case we care what it *was*
                $watches_replaced++;
                $self->log("$type '$path' was replaced, replacing watch") if $debug;
            }
        }

        my $watch = $notifier->watch(
            $path,
            (
                # Is this is a directory?
                ($type eq 'directory' ?
                    # Modifications I care about
                    IN_MODIFY
                    |
                    IN_ATTRIB
                    |
                    IN_CREATE
                    |
                    IN_DELETE
                    |
                    IN_DELETE_SELF
                    |
                    IN_MOVED_FROM
                    |
                    IN_MOVED_TO
                    |
                    IN_MOVE_SELF
                :
                    # modifications for files
                    IN_MODIFY
                    |
                    IN_ATTRIB
                    |
                    IN_CLOSE_WRITE
                    |
                    IN_DELETE_SELF
                    |
                    IN_MOVE_SELF
                )
            )
        );

        if (not $watch) {
            my $error = $!;

            if ($error == ENOSPC) {
                die <<"DIE"
We probably exceeded the maximum number of user watches since we had a
"No space left on device" error. Try something like this command and
try again:

    echo 65536 | sudo tee /proc/sys/fs/inotify/max_user_watches

The original error was:

$error
DIE
            } elsif ($error == ENOENT) {
                # Don't hard die on the common race condition where a
                # file/directory we found with our "find" call has
                # since gone away (e.g. due to a different "git
                # checkout" removing it).
                $self->log("Couldn't watch $type '$path': $error");
                next WATCH;
            } else {
                die $error;
            }
        }

        $watches_added++;
        $self->log("Now watching $type: $path") if !$have_watch && $debug;

        $watches->{$path}{watch} = $watch;
        $watches->{$path}{type}  = $type;
        $watches->{$path}{inode} = $inode_number;
    }

    # Set this to the stuff we were just going over so we'll know to
    # delete stuff from there in the future.
    $self->_previously_watched_directories(\@current_paths_to_watch);

    my $elapsed = tv_interval ( $t0 );
    my $total_num_watches = scalar keys %{ $notifier->{w} };
    $self->log(sprintf "FINISHED setting up watches. Took %.2fs with $watches_added watches added, $watches_removed removed, $watches_replaced replaced. Have $total_num_watches total watches", $elapsed);
    return;
}

sub _build__bitmask {
    my %masks;
    @masks{grep /^IN_/, @{ Class::Inspector->methods("Linux::Inotify2") }} = ();
    foreach my $const (keys %masks) {
        $masks{$const} = Linux::Inotify2->$const;
    }

    return Data::BitMask->new(%masks);
}

sub DEMOLISH {
    my ($self) = @_;
    my $notifier = $self->_notifier;

    $self->log("Demolishing $notifier");
}

1;

__END__

=encoding utf8

=head1 NAME

inotify-hookable - blocking command-line interface to inotify

=head1 SYNOPSIS

Watch a directory, tell us when things change in it:

    inotify-hookable --watch-directories /tmp/watch-this

Watch a git tree, some configs, and a repository of static assets,
restart the webserver or compress those assets if anything changes:

    inotify-hookable \
        --watch-directories /etc/uwsgi \
        --watch-directories /git_tree/central \
        --watch-directories /etc/app-config \
        --watch-directories /git_tree/static_assets \
        --on-modify-path-command "^(/etc/uwsgi|/git_tree/central|/etc/app-config)=sudo /etc/init.d/uwsgi restart" \
        --on-modify-path-command "^/git_tree/static_assets=(cd /git_tree/static_assets && compress_static_assets)"

Or watch specific files:

    inotify-hookable \
        --watch-files /var/www/cgi-bin/mod_perl_handler \
        --on-modify-command "apachectl restart"

=head1 DESCRIPTION

This simple command-line program is my replacement for the
functionality offered by L<Plack>'s L<Filesys::Notify::Simple>. I
found that on very large git trees Plack would spend an inordinate
amount watching the filesystem for changes.

This program uses L<Linux::Inotify2>, so the kernel will notify it
B<instantly> when something changes (actually it's so fast that we
have to work around how fast it sends us events).

The result is that you can run this e.g. in a screen session and have
it watch your development environment, and your webserver will have
begun restarting before your finger leaves the I<save> button.

vim and emacs temporary files are ignored by default (see C<--ignore-paths>.)
so you can edit your files without your server restarting unnecessarily.

Currently the command-line interface for this is the only one that
really makes sense, this module is entirely blocking (although it
could probably run in another process via L<POE> or
something). Patches welcome.

=head1 OPTIONS

Note that boolean options can be negated with C<--no-OPTION>,
e.g. C<--no-r> or C<--no-recursive> to turn off the C<--recursive>
option which is on by default.

=head2 C<-w> or C<--watch-directories>

Specify this to watch a directory, you can give this however many
times you like to watch lots of directories.

=head2 C<-f> or C<--watch-files>

Watch a file, specify multiple times for multiple files.
You can watch files and directories in the same command.

=head2 C<-r> or C<--recursive>

If you supply this any directory you give will be recursively
watched. This is on by default.

=head2 C<-c> or C<--on-modify-command>

A command that will be run when something is modified.

=head2 C<-C> or C<--on-modify-path-command>

A key-value pair where the key is a regex that'll be matched against a
modified path, and the value is a command that'll be run. See the
L</SYNOPSIS> for an example.

Useful for e.g. restarting a webserver if you modify directory F<A>
but compressing some static assets if you modify directory F<B>.

=head2 C<-t> or C<--buffer-time>

Linux will send you inotify events B<really> fast, so fast that if you
run something like:

    touch foo bar

You might get an event for F<foo> in one batch, followed by an event
for F<bar> later on.

To deal with this we enter a loop when we start getting events and sleep for a
default of 100 microseconds, as long as we keep getting events we keep sleeping
for 100 microseconds, but as soon as we haven't received anything new we fire
off our event handlers.

=head2 C<-i> or C<--ignore-paths>

Regexes for files/directories to ignore events for. By default this is set to
regexes for vim and emacs temporary files, C<qr{\..*sw.\z}> and
C<qr{\.\#[^/]+\z}> respectively.

The regexes match after any C</> in the path or the beginning of the string.

=head2 C<-d> or C<--debug>

Spew out some verbose debug output while running.

=head1 ACKNOWLEDGMENT

This module was originally developed at and for Booking.com. With
approval from Booking.com, this module was generalized and put on
CPAN, for which the authors would like to express their gratitude.

=head1 AUTHOR

Ævar Arnfjörð Bjarmason <avar@cpan.org>

=cut