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
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
|
#!perl5
use strict;
package Log::ErrLogger;
=head1 NAME
Log::ErrLogger - Log errors and error-like events
=head1 SYNOPSIS
use Log::ErrLogger;
# Send e-mail for ERROR or worse
my $mail_logger = new Log::ErrLogger::Mail(
SENSITIVITY => Log::ErrLogger::ERROR,
HEADERS => { To => "who@where.com",
Subject => "Errors occurred while running $0" });
# Log INFORMATIONAL or worse to a file
my $file_logger = new Log::ErrLogger::File(
FILE => "/home/who/what.err",
SENSITIVITY => Log::ErrLogger::INFORMATIONAL );
# Print a nice HTML error message
my $sub_logger = new Log::ErrLogger::Sub (
SENSITIVITY => FATAL,
SUB => sub { print STDOUT "<TITLE>Oops!</TITLE><HTML><HEAD1>Please try again later.</HEAD1></HTML>\n";
exit(0); } );
# Capture all output to STDERR as an UNEXPECTED error
my $stderr_logger = Log::ErrLogger::tie( Log::ErrLogger::UNEXPECTED );
# But don't actually print to STDERR
$stderr_logger->close;
# Log a warning
log_error( WARNING, "Danger, %s!", "Will Robinson" );
=head1 DESCRIPTION
Log::ErrLogger provides a means of logging errors and error-like events (such
as warnings and unexpected situations) when printing to STDERR just will not do.
Error-like events are classified by a severity (see L<ERROR SEVERITIES> below).
Programs instantiate error logging objects which can respond differently to
events. The objects have a sensitivity -- they will respond to any event at
least as severe as their sensitivity, and will ignore any events that are less
severe.
This module instantiates new __DIE__ and __WARN__ handlers that call
log_error( FATAL, die-message) and log_error( WARNING, warn-message), respectively.
=head1 HISTORY
$Id: ErrLogger.pm,v 1.6 1999/09/23 21:37:24 dcw Exp $
$Log: ErrLogger.pm,v $
Revision 1.6 1999/09/23 21:37:24 dcw
Incorporated Tim Ayers <tayers@bridge.com> suggestions
Revision 1.5 1999/09/13 17:59:48 dcw
Copyright
Revision 1.4 1999/09/13 16:37:17 dcw
Documentation
Revision 1.3 1999/09/01 14:28:28 dcw
Backup file, export, autoflush
Revision 1.2 1999/08/31 17:18:39 dcw
Log::ErrLogger::Sub
Revision 1.1 1999/08/30 21:28:43 dcw
Initial
=head1 AUTHOR
David C. Worenklein <dcw@gcm.com>
=head1 COPYRIGHT
Copyright 1999 Greenwich Capital Markets
This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=head1 ERROR SEVERITIES
The predefined severities are
=over 4
=item DEBUGGING
=item INFORMATIONAL
=item UNEXPECTED
=item WARNING
=item ERROR
=item FATAL
=back
They have numerical values from 1 to 6.
=cut
use vars qw{@Errors};
BEGIN {
@Errors = qw{
ALL
DEBUGGING
INFORMATIONAL
UNEXPECTED
WARNING
ERROR
FATAL
NONE
};
}
#################################
# Typical object-oriented stuff #
#################################
use Exporter;
use vars qw{ @ISA @EXPORT_OK %EXPORT_TAGS $VERSION };
@ISA = qw{ Exporter };
@EXPORT_OK = (@Errors, "log_error", "tie", "LogError", "Tie");
%EXPORT_TAGS = (ErrorLevels => [@Errors]);
($VERSION) = ( qw$Revision: 1.6 $ )[1];
use IO::Handle;
##############
# Prototypes #
##############
sub log_error( $$;@ );
sub tie( ;$ );
sub new( $;% );
# Prototypes don't do much for methods, but they make the code more readable.
sub sensitivity( $ );
sub set_sensitivity( $$ );
sub file_handle( $ );
sub set_file_handle( $$ );
sub log( $$$ );
sub close( $ );
###############################
# Set up the error severities #
###############################
for(my $i=0; $i<scalar(@Errors); $i++) {
eval " use constant $Errors[$i] => $i ";
}
###########################
# Commandeer DIE and WARN #
###########################
$SIG{__DIE__} = sub { if (defined($^S)) { Log::ErrLogger::log_error( &Log::ErrLogger::FATAL, "%s", @_ ); } else { die @_; } };
$SIG{__WARN__} = sub { if (defined($^S)) { Log::ErrLogger::log_error( &Log::ErrLogger::WARNING, "%s", @_ ); } else { warn @_; } };
##########################################
# Here are the logging methods specified #
##########################################
my @LogMethods;
=head1 NON-METHOD SUBROUTINES
=over 4
=item log_error( SEVERITY, FORMAT [,LIST] )
Log an error of the specified severity. The text of the message is the output of
sprintf FORMAT, ARGS. A carriage-return (\n) will be appended if one is not
supplied.
=cut
sub log_error( $$;@ ) {
my ($severity, $format, @args) = @_;
my $message = sprintf $format, @args;
# Add \n if needed
$message .= "\n" unless substr($message, -1) eq "\n";
my $fatal;
foreach my $logger (@LogMethods) {
if ($logger->sensitivity <= $severity) {
# An error logger can attempt to die
eval { $logger->log( $severity, $message ) };
$fatal ||= $@;
}
}
# Did we hit a dieing error logger?
die $fatal if $fatal;
}
*LogError = \&log_error;
###############################################################################
=item my $stderr_logger = tie( [SEVERITY] );
Tie the STDERR handle to the Log::ErrLogger module, so that any output to
STDERR will call log_error( $severity, output ).
If $severity is not specified, it will default to INFORMATIONAL.
=cut
my $stderr_handler;
sub tie( ;$ ) {
my ($severity) = @_;
$severity = &INFORMATIONAL unless defined($severity);
my $handler = new Log::ErrLogger SENSITIVITY => $severity;
# Copy off what STDERR was
open(OLD_STDERR, ">&STDERR");
$handler->set_file_handle(*OLD_STDERR);
$stderr_handler = tie *STDERR, ref($handler), $severity;
return $handler;
}
*Tie = \&tie;
sub TIEHANDLE( $ ) {
my ($class, $severity) = @_;
return bless \$severity, $class;
}
sub PRINT( $$ ) {
my ($self, $message) = @_;
Log::ErrLogger::log_error( $$self, "%s", $message );
}
sub PRINTF( $$;@ ) {
my ($self, $format, @args) = @_;
Log::ErrLogger::log_error( $$self, $format, @args );
}
###############################################################################
=back
=head1 METHODS
=over 4
=item my $sensitivity = $logger->sensitivity;
Returns the sensitivty of an error logger object. Objects respond to
events that are at least as severe as their sensitivity. There are
two special sensitivities. Objects with a sensitivity of NONE do not
respond to any events. Objects with a sensitivity of ALL respond
to all events.
=cut
sub sensitivity( $ ) {
my ($self) = @_;
return $self->{SENSITIVITY};
}
###############################################################################
=item my $old_sensitivity = $logger->sensitivity( SENSITIVITY );
Sets the sensitivty of an error logger object. Objects respond to events
that are at least as severe as their sensitivity.
Returns what the sensitivity of the object used to be.
=cut
sub set_sensitivity( $$ ) {
my ($self, $sensitivity) = @_;
my $old_sensitivity = $self->{SENSITIVITY};
$self->{SENSITIVITY} = $sensitivity;
return $old_sensitivity;
}
###############################################################################
=item my $fh = $logger->file_handle;
Returns the IO::Handle associated with the error logger object. Not all
error loggers will have a file handle, but most will.
=cut
sub file_handle( $ ) {
my ($self) = @_;
return $self->{FILEHANDLE};
}
###############################################################################
=item $logger->set_file_handle( HANDLE );
Associates the error logger object with the given (opened) IO::Handle, and
closes the old file handle that used to be associated with the object (if
there was one.)
The handle is set to autoflush, since buffering is usually a bad idea on
error loggers.
=cut
sub set_file_handle( $$ ) {
my ($self, $handle) = @_;
if (defined($self->file_handle)) {
$self->file_handle->close;
}
$self->{FILEHANDLE} = $handle;
$self->{FILEHANDLE}->autoflush(1);
}
###############################################################################
=item $logger->close;
Decommission the error logging object. L<log_error> will no longer invoke
this object.
Note that this does NOT close the associated file handle. However, if the
error logging object has the only reference to the file handle, and the
program does not have any references to the error logging object, the handle
will have no references left and will be destroyed.
=cut
sub close( $ ) {
my ($self) = @_;
@LogMethods = grep { $_ != $self } @LogMethods;
}
###############################################################################
=item $logger->log( SEVERITY, MESSAGE );
This is the method called by L<log_error>, above. It prints
<time>: <message>
to the associated file handle, where <time> is the output of L<localtime>,
evaluated in a scalar context.
Additionally, if the object has a TRACE attribute that is at least
as large as the error severity, this method will print a trace of where
the error occurred:
<spaces>: From <subroutine1>, at <filename1>:<line1>
<spaces>: From <subroutine2>, at <filename2>:<line2>
where <spaces> is the number of spaces needed to make all the colons line up.
=cut
sub log( $$$ ) {
my ($self, $severity, $message) = @_;
if (defined($self->file_handle)) {
my $time = scalar(localtime);
print { $self->file_handle } "$time: $message";
if (defined($self->{TRACE}) && $self->{TRACE} >= $severity) {
# Show context
my $i=1;
my ($package, $filename, $line, $subroutine) = caller($i);
while(defined($subroutine)) {
printf { $self->file_handle } "%s: From %s, at %s:%s\n", " "x length($time), $subroutine, $filename, $line
if ($filename ne __FILE__ && $subroutine !~ /^Log::ErrLogger/);
($package, $filename, $line, $subroutine) = caller(++$i);
}
}
}
}
###############################################################################
=back
=head1 CONSTRUCTORS
The following erorr logging classes are provided by the module:
=over 4
=item my $logger = new Log::ErrLogger( [parameter-hash] );
Creates a new error logging object that uses the default L<log>
given above. The parameters that are understood are
=over 4
=item SENSITIVITY
The sensitivity of the object. Defaults to INFORMATIONAL or, in
the perl debugger, DEBUGGING.
=item TRACE
Events that are at least as severe as the TRACE value will have their
call stack printed.
=back
=cut
sub new( $;% ) {
my ($class, %options) = @_;
my $self = bless { %options }, $class;
if (!defined( $self->sensitivity )) {
$self->set_sensitivity( $^P ? &DEBUGGING : &INFORMATIONAL );
}
push(@LogMethods, $self);
return $self;
}
###############################################################################
=item my $logger = new Log::ErrLogger::File( [parameter-hash] );
Creates an error logging object that logs events to a file. In addition
to the parameters that the Log::ErrLogger constructor takes, it also
takes
=over 4
=item FILE
Name of the file that in which to log events. Defaults to /tmp/<program-base-name>.<pid>.err.
See the L<set_file> method, below, for details.
=back
=cut
package Log::ErrLogger::File;
use vars qw{ @ISA $VERSION };
@ISA = qw{ Log::ErrLogger };
$VERSION = $Log::ErrLogger::VERSION;
use IO::File;
# Prototypes don't do much for methods, but they make the code more readable.
sub new( $;% );
sub filename( $ );
sub set_file( $$ );
sub new( $;% ) {
my ($class, %options) = @_;
# Default file name
$0 =~ m:([^/]+)$:;
$options{FILE} ||= "/tmp/$1.$$.err";
my $self = Log::ErrLogger::new( $class, %options );
$self->set_file( $self->filename );
return $self;
}
###############################################################################
=pod
Log::ErrLogger::File objects also provides the following methods:
=over 4
=item my $filename = $filelogger->filename();
Returns the name of the file to which events are logger.
=cut
sub filename( $ ) {
my ($self) = @_;
return $self->{FILE};
}
###############################################################################
=item my $old_filename = $filelogger->set_file( $new_filename [, mode [, perms]])
Opens the given file for output and sets its FILEHANDLE to that file. An ERROR
event is generated if the file could not be opened.
Note that the file is opened by putting a ">" at the beginning and creating a
new IO::File object. This means that if the filename given already begins with
a ">", the file will be opened for appending.
If the file already exists, it is renamed by appending ".bak" to it. A WARNING
event is generated if the file could not be backed up.
Returns the old filename that errors used to be logged to.
=cut
sub set_file( $$ ) {
my ($self, $file) = @_;
my $oldfile = $self->filename;
# Try to create a backup file
if ( -f $file ) {
my $backup = $file . ".bak";
!-f $backup || unlink($backup) ||
Log::ErrLogger::log_error( &Log::ErrLogger::WARNING, "Could not remove old backup file %s: %s", $backup, $!);
rename( $file, $backup) ||
Log::ErrLogger::log_error( &Log::ErrLogger::WARNING, "Could not create backup file %s: %s", $backup, $!);
}
$self->{FILE} = $file;
$self->set_file_handle(new IO::File ">$file");
if (defined($self->file_handle)) {
$self->file_handle->autoflush(1);
} else {
Log::ErrLogger::log_error( &Log::ErrLogger::ERROR, "Could not open file %s: %s", $file, $! );
}
return $oldfile;
}
###############################################################################
=back
=item my $logger = new Log::ErrLogger::Mail( [parameter-hash] );
Log events by sending email to interested parties. In addition to the
parameters that the Log::ErrLogger constructor takes, it also takes
=over 4
=item HEADERS
A reference to a hash containing the headers of the e-mail, such as To and
Subject.
=back
If no sufficiently severe events occur, no email is sent. (In other words,
you will not get a blank e-mail.)
=cut
package Log::ErrLogger::Mail;
use vars qw{ @ISA $VERSION };
@ISA = qw{ Log::ErrLogger };
$VERSION = $Log::ErrLogger::VERSION;
use Mail::Mailer;
# Prototypes don't do much for methods, but they make the code more readable.
sub new( $;% );
sub log( $$$ );
sub new( $;% ) {
my ($class, %options) = @_;
return Log::ErrLogger::new( $class, %options );
}
##############################################################
# Log an error. This is where we set up the e-mail message. #
# If this is never called, mail is never sent. #
##############################################################
sub log( $$$ ) {
my ($self, $severity, $message) = @_;
if (!defined($self->file_handle)) {
$self->set_file_handle( new Mail::Mailer 'smtp', Server => "127.0.0.1" );
$self->file_handle->open( $self->{HEADERS} );
}
$self->SUPER::log($severity, $message);
}
###############################################################################
=item my $logger = new Log::ErrLogger::Sub( [parameter-hash] );
Calls a user specified subroutine every time a sufficiently severe events occurs.
In addition to the parameters that the Log::ErrLogger constructor takes, it also
takes
=over 4
=item SUB
A reference (regular or symbolic) to the subroutine to be called. The
subroutine will receive two parameters -- the event message and the
error severity. This parameter MUST be supplied to the constructor.
Note that, within this subroutine, STDERR is what you would want it to
be, even if the program has used tie to capture STDERR. Thus, the
subroutine does not have to worry that output to STDERR will cause
infinite recursion.
=cut
package Log::ErrLogger::Sub;
use vars qw{ @ISA $VERSION };
@ISA = qw{ Log::ErrLogger };
$VERSION = $Log::ErrLogger::VERSION;
# Prototypes don't do much for methods, but they make the code more readable.
sub new( $;% );
sub log( $$$ );
##########################################################################
# Create a new instance that causes errors to be logged via a subroutine #
##########################################################################
use Carp;
sub new( $;% ) {
my ($class, %options) = @_;
if (!exists($options{SUB})) {
croak __PACKAGE__ . " must have a SUB specified";
}
return Log::ErrLogger::new( $class, %options );
}
########################################################
# Log an error by calling a user specified subroutine. #
########################################################
sub log( $$$ ) {
my ($self, $severity, $message) = @_;
# Put back the old STDERR, if necessary
if ($stderr_handler) {
local($^W)=0; # Don't care that untie attempted
untie *STDERR;
open(STDERR, ">&Log::ErrLogger::OLD_STDERR");
}
if (ref($self->{SUB}) eq "CODE") {
&{$self->{SUB}}($message, $severity);
} else {
eval "$self->{SUB}(\$message, \$severity)";
}
if ($stderr_handler) {
$stderr_handler = tie *STDERR, ref($stderr_handler), $$stderr_handler;
}
}
1;
|
