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Revision 1.17 by root, Sat Aug 20 02:21:53 2011 UTC vs.
Revision 1.31 by root, Thu Aug 25 03:08:48 2011 UTC

2 2
3AnyEvent::Log - simple logging "framework" 3AnyEvent::Log - simple logging "framework"
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 # simple use 7Simple uses:
8
8 use AnyEvent; 9 use AnyEvent;
9 10
10 AE::log debug => "hit my knee"; 11 AE::log debug => "hit my knee";
11 AE::log warn => "it's a bit too hot"; 12 AE::log warn => "it's a bit too hot";
12 AE::log error => "the flag was false!"; 13 AE::log error => "the flag was false!";
13 AE::log fatal => "the bit toggled! run!"; 14 AE::log fatal => "the bit toggled! run!"; # never returns
14 15
15 # "complex" use 16"Complex" uses (for speed sensitive code):
17
16 use AnyEvent::Log; 18 use AnyEvent::Log;
17 19
18 my $tracer = AnyEvent::Log::logger trace => \$my $trace; 20 my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19 21
20 $tracer->("i am here") if $trace; 22 $tracer->("i am here") if $trace;
21 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace; 23 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22 24
23 # configuration 25Configuration (also look at the EXAMPLES section):
24 26
25 # set logging for this package to errors and higher only 27 # set logging for the current package to errors and higher only
26 AnyEvent::Log::ctx->level ("error"); 28 AnyEvent::Log::ctx->level ("error");
27 29
28 # set logging globally to anything below debug 30 # set logging level to suppress anything below "notice"
29 $AnyEvent::Log::Root->level ("notice"); 31 $AnyEvent::Log::FILTER->level ("notice");
30 32
31 # see also EXAMPLES, below 33 # send all critical and higher priority messages to syslog,
34 # regardless of (most) other settings
35 $AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
36 level => "critical",
37 log_to_syslog => 0,
38 );
32 39
33=head1 DESCRIPTION 40=head1 DESCRIPTION
34 41
35This module implements a relatively simple "logging framework". It doesn't 42This module implements a relatively simple "logging framework". It doesn't
36attempt to be "the" logging solution or even "a" logging solution for 43attempt to be "the" logging solution or even "a" logging solution for
37AnyEvent - AnyEvent simply creates logging messages internally, and this 44AnyEvent - AnyEvent simply creates logging messages internally, and this
38module more or less exposes the mechanism, with some extra spiff to allow 45module more or less exposes the mechanism, with some extra spiff to allow
39using it from other modules as well. 46using it from other modules as well.
40 47
41Remember that the default verbosity level is C<0>, so nothing will be 48Remember that the default verbosity level is C<0> (C<off>), so nothing
42logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before 49will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
43starting your program, or change the logging level at runtime with 50before starting your program, or change the logging level at runtime with
44something like: 51something like:
45 52
46 use AnyEvent; 53 use AnyEvent::Log;
47 (AnyEvent::Log::ctx "")->level ("info"); 54 AnyEvent::Log::FILTER->level ("info");
48 55
49The design goal behind this module was to keep it simple (and small), 56The design goal behind this module was to keep it simple (and small),
50but make it powerful enough to be potentially useful for any module, and 57but make it powerful enough to be potentially useful for any module, and
51extensive enough for the most common tasks, such as logging to multiple 58extensive enough for the most common tasks, such as logging to multiple
52targets, or being able to log into a database. 59targets, or being able to log into a database.
53 60
54The amount of documentation might indicate otherwise, but the module is 61The amount of documentation might indicate otherwise, but the module is
55still just 240 lines or so. 62still just below 300 lines of code.
63
64=head1 LOGGING LEVELS
65
66Logging levels in this module range from C<1> (highest priority) to C<9>
67(lowest priority). Note that the lowest numerical value is the highest
68priority, so when this document says "higher priority" it means "lower
69numerical value".
70
71Instead of specifying levels by name you can also specify them by aliases:
72
73 LVL NAME SYSLOG PERL NOTE
74 1 fatal emerg exit aborts program!
75 2 alert
76 3 critical crit
77 4 error err die
78 5 warn warning
79 6 note notice
80 7 info
81 8 debug
82 9 trace
83
84As you can see, some logging levels have multiple aliases - the first one
85is the "official" name, the second one the "syslog" name (if it differs)
86and the third one the "perl" name, suggesting that you log C<die> messages
87at C<error> priority.
88
89You can normally only log a single message at highest priority level
90(C<1>, C<fatal>), because logging a fatal message will also quit the
91program - so use it sparingly :)
92
93Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
94or C<all> - these are only valid in the methods they are documented for.
56 95
57=head1 LOGGING FUNCTIONS 96=head1 LOGGING FUNCTIONS
58 97
59These functions allow you to log messages. They always use the caller's 98These functions allow you to log messages. They always use the caller's
60package as a "logging module/source". Also, the main logging function is 99package as a "logging context". Also, the main logging function C<log> is
61callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is 100callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
62loaded. 101loaded.
63 102
64=over 4 103=over 4
65 104
72 111
73use AnyEvent (); BEGIN { AnyEvent::common_sense } 112use AnyEvent (); BEGIN { AnyEvent::common_sense }
74use AnyEvent::Util (); 113use AnyEvent::Util ();
75 114
76our $VERSION = $AnyEvent::VERSION; 115our $VERSION = $AnyEvent::VERSION;
116
117our ($COLLECT, $FILTER, $LOG);
77 118
78our ($now_int, $now_str1, $now_str2); 119our ($now_int, $now_str1, $now_str2);
79 120
80# Format Time, not public - yet? 121# Format Time, not public - yet?
81sub ft($) { 122sub ft($) {
86 if $now_int != $i; 127 if $now_int != $i;
87 128
88 "$now_str1$f$now_str2" 129 "$now_str1$f$now_str2"
89} 130}
90 131
91our %CTX; # all logging contexts 132our %CTX; # all package contexts
92 133
93# creates a default package context object for the given package 134# creates a default package context object for the given package
94sub _pkg_ctx($) { 135sub _pkg_ctx($) {
95 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx"; 136 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
96 137
97 # link "parent" package 138 # link "parent" package
98 my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top"; 139 my $parent = $_[0] =~ /^(.+)::/
140 ? $CTX{$1} ||= &_pkg_ctx ("$1")
141 : $COLLECT;
99 142
100 $pkg = $CTX{$pkg} ||= &_pkg_ctx ($pkg);
101 $ctx->[2]{$pkg+0} = $pkg; 143 $ctx->[2]{$parent+0} = $parent;
102 144
103 $ctx 145 $ctx
104} 146}
105 147
106=item AnyEvent::Log::log $level, $msg[, @args] 148=item AnyEvent::Log::log $level, $msg[, @args]
107 149
108Requests logging of the given C<$msg> with the given log level (1..9). 150Requests logging of the given C<$msg> with the given log level, and
109You can also use the following strings as log level: C<fatal> (1), 151returns true if the message was logged I<somewhere>.
110C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
111C<info> (7), C<debug> (8), C<trace> (9).
112 152
113For C<fatal> log levels, the program will abort. 153For C<fatal> log levels, the program will abort.
114 154
115If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the 155If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
116C<$msg> is interpreted as an sprintf format string. 156C<$msg> is interpreted as an sprintf format string.
122supposed to return the message. It will be called only then the message 162supposed to return the message. It will be called only then the message
123actually gets logged, which is useful if it is costly to create the 163actually gets logged, which is useful if it is costly to create the
124message in the first place. 164message in the first place.
125 165
126Whether the given message will be logged depends on the maximum log level 166Whether the given message will be logged depends on the maximum log level
127and the caller's package. 167and the caller's package. The return value can be used to ensure that
168messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
169runtime error it tries to log it at C<die> level, but if that message is
170lost it simply uses warn.
128 171
129Note that you can (and should) call this function as C<AnyEvent::log> or 172Note that you can (and should) call this function as C<AnyEvent::log> or
130C<AE::log>, without C<use>-ing this module if possible (i.e. you don't 173C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
131need any additional functionality), as those functions will load the 174need any additional functionality), as those functions will load the
132logging module on demand only. They are also much shorter to write. 175logging module on demand only. They are also much shorter to write.
149 192
150=cut 193=cut
151 194
152# also allow syslog equivalent names 195# also allow syslog equivalent names
153our %STR2LEVEL = ( 196our %STR2LEVEL = (
154 fatal => 1, emerg => 1, 197 fatal => 1, emerg => 1, exit => 1,
155 alert => 2, 198 alert => 2,
156 critical => 3, crit => 3, 199 critical => 3, crit => 3,
157 error => 4, err => 4, 200 error => 4, err => 4, die => 4,
158 warn => 5, warning => 5, 201 warn => 5, warning => 5,
159 note => 6, notice => 6, 202 note => 6, notice => 6,
160 info => 7, 203 info => 7,
161 debug => 8, 204 debug => 8,
162 trace => 9, 205 trace => 9,
192 ? $level+0 235 ? $level+0
193 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 236 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
194 237
195 my $mask = 1 << $level; 238 my $mask = 1 << $level;
196 239
197 my (%seen, @ctx, $now, $fmt); 240 my ($success, %seen, @ctx, $now, $fmt);
198 241
199 do 242 do
200 { 243 {
201 # skip if masked 244 # skip if masked
202 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) { 245 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
206 # now get raw message, unless we have it already 249 # now get raw message, unless we have it already
207 unless ($now) { 250 unless ($now) {
208 $format = $format->() if ref $format; 251 $format = $format->() if ref $format;
209 $format = sprintf $format, @args if @args; 252 $format = sprintf $format, @args if @args;
210 $format =~ s/\n$//; 253 $format =~ s/\n$//;
211 $now = AE::now; 254 $now = now;
212 }; 255 };
213 256
214 # format msg 257 # format msg
215 my $str = $ctx->[4] 258 my $str = $ctx->[4]
216 ? $ctx->[4]($now, $_[0], $level, $format) 259 ? $ctx->[4]($now, $_[0], $level, $format)
217 : $fmt ||= _format $now, $_[0], $level, $format; 260 : ($fmt ||= _format $now, $_[0], $level, $format);
218 261
262 $success = 1;
263
219 $ctx->[3]($str); 264 $ctx->[3]($str)
265 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
266 } else {
267 push @ctx, values %{ $ctx->[2] }; # not masked - propagate
220 } 268 }
221
222 # not masked, not consumed - propagate to parent contexts
223 push @ctx, values %{ $ctx->[2] };
224 } 269 }
225 } 270 }
226 while $ctx = pop @ctx; 271 while $ctx = pop @ctx;
227 272
228 exit 1 if $level <= 1; 273 exit 1 if $level <= 1;
274
275 $success
229} 276}
230 277
231sub log($$;@) { 278sub log($$;@) {
232 _log 279 _log
233 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 280 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
237*AnyEvent::log = *AE::log = \&log; 284*AnyEvent::log = *AE::log = \&log;
238 285
239=item $logger = AnyEvent::Log::logger $level[, \$enabled] 286=item $logger = AnyEvent::Log::logger $level[, \$enabled]
240 287
241Creates a code reference that, when called, acts as if the 288Creates a code reference that, when called, acts as if the
242C<AnyEvent::Log::log> function was called at this point with the givne 289C<AnyEvent::Log::log> function was called at this point with the given
243level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with 290level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
244the C<AnyEvent::Log::log> function: 291the C<AnyEvent::Log::log> function:
245 292
246 my $debug_log = AnyEvent::Log::logger "debug"; 293 my $debug_log = AnyEvent::Log::logger "debug";
247 294
347timestamp, context, level and string message and formats it in the way 394timestamp, context, level and string message and formats it in the way
348it should be logged) and a logging callback (which is responsible for 395it should be logged) and a logging callback (which is responsible for
349actually logging the formatted message and telling C<AnyEvent::Log> 396actually logging the formatted message and telling C<AnyEvent::Log>
350whether it has consumed the message, or whether it should be propagated). 397whether it has consumed the message, or whether it should be propagated).
351 398
352For propagation, a context can have any number of attached I<parent 399For propagation, a context can have any number of attached I<slave
353contexts>. Any message that is neither masked by the logging mask nor 400contexts>. Any message that is neither masked by the logging mask nor
354masked by the logging callback returning true will be passed to all parent 401masked by the logging callback returning true will be passed to all slave
355contexts. 402contexts.
356 403
357Each call to a logging function will log the message at most once per 404Each call to a logging function will log the message at most once per
358context, so it does not matter (much) if there are cycles or if the 405context, so it does not matter (much) if there are cycles or if the
359message can arrive at the same context via multiple paths. 406message can arrive at the same context via multiple paths.
363By default, all logging contexts have an full set of log levels ("all"), a 410By default, all logging contexts have an full set of log levels ("all"), a
364disabled logging callback and the default formatting callback. 411disabled logging callback and the default formatting callback.
365 412
366Package contexts have the package name as logging title by default. 413Package contexts have the package name as logging title by default.
367 414
368They have exactly one parent - the context of the "parent" package. The 415They have exactly one slave - the context of the "parent" package. The
369parent package is simply defined to be the package name without the last 416parent package is simply defined to be the package name without the last
370component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>, 417component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the 418and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
372exception of the rule - just like the parent of any package name in 419exception of the rule - just like the "parent" of any single-component
373Perl is C<main>, the default parent of any top-level package context is 420package name in Perl is C<main>, the default slave of any top-level
374C<AnyEvent::Log::Top>. 421package context is C<$AnyEvent::Log::COLLECT>.
375 422
376Since perl packages form only an approximate hierarchy, this parent 423Since perl packages form only an approximate hierarchy, this slave
377context can of course be removed. 424context can of course be removed.
378 425
379All other (anonymous) contexts have no parents and an empty title by 426All other (anonymous) contexts have no slaves and an empty title by
380default. 427default.
381 428
382When the module is loaded it creates the default context called 429When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
383C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>), 430context that simply logs everything via C<warn>, without propagating
384which simply logs everything via C<warn> and doesn't propagate anything
385anywhere by default. The purpose of the default context is to provide 431anything anywhere by default. The purpose of this context is to provide
386a convenient place to override the global logging target or to attach 432a convenient place to override the global logging target or to attach
387additional log targets. It's not meant for filtering. 433additional log targets. It's not meant for filtering.
388 434
389It then creates the root context called C<AnyEvent::Log::Root> (also 435It then creates the C<$AnyEvent::Log::FILTER> context whose
390stored in C<$AnyEvent::Log::Root>) and sets its log level set to all 436purpose is to suppress all messages with priority higher
391levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It 437than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
392then attached the default logging context to it. The purpose of the root 438C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
393context is to simply provide filtering according to some global log level. 439is to simply provide filtering according to some global log level.
394 440
395Finally it creates the top-level package context called 441Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
396C<AnyEvent::Log::Top> (also stored in, you might have guessed, 442and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
397C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
398it at default config. It's purpose is simply to collect all log messages 443leaves it at default config. Its purpose is simply to collect all log
399system-wide. 444messages system-wide.
400 445
401These three special contexts can also be referred to by the 446The hierarchy is then:
402package/context names C<AE::Log::Default>, C<AE::Log::Root> and
403C<AE::Log::Top>.
404 447
448 any package, eventually -> $COLLECT -> $FILTER -> $LOG
449
405The effect of all this is that log messages, by default, wander up 450The effect of all this is that log messages, by default, wander up to the
406to the root context where log messages with lower priority then 451C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
452from there to C<$AnyEvent::Log::FILTER> where log messages with lower
407C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the 453priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
408AnyEvent::Log::Default context to be passed to C<warn>. 454to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
409 455
410Splitting the top level context into three contexts makes it easy to set 456This makes it easy to set a global logging level (by modifying $FILTER),
411a global logging level (by modifying the root context), but still allow 457but still allow other contexts to send, for example, their debug and trace
412other contexts to log, for example, their debug and trace messages to the
413default target despite the global logging level, or to attach additional 458messages to the $LOG target despite the global logging level, or to attach
414log targets that log messages, regardless of the global logging level. 459additional log targets that log messages, regardless of the global logging
460level.
415 461
416It also makes it easy to replace the default warn-logger by something that 462It also makes it easy to modify the default warn-logger ($LOG) to
417logs to a file, or to attach additional logging targets. 463something that logs to a file, or to attach additional logging targets
464(such as loggign to a file) by attaching it to $FILTER.
418 465
419=head2 CREATING/FINDING/DESTROYING CONTEXTS 466=head2 CREATING/FINDING/DESTROYING CONTEXTS
420 467
421=over 4 468=over 4
422 469
456 503
457=cut 504=cut
458 505
459sub reset { 506sub reset {
460 # hard to kill complex data structures 507 # hard to kill complex data structures
461 # we recreate all package loggers and reset the hierarchy 508 # we "recreate" all package loggers and reset the hierarchy
462 while (my ($k, $v) = each %CTX) { 509 while (my ($k, $v) = each %CTX) {
463 @$v = ($k, (1 << 10) - 1 - 1, { }); 510 @$v = ($k, (1 << 10) - 1 - 1, { });
464 511
465 my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top"; 512 $v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
466 $v->attach ($CTX{$pkg});
467 } 513 }
468 514
469 $AnyEvent::Log::Default->parents; 515 @$_ = ($_->[0], (1 << 10) - 1 - 1)
470 $AnyEvent::Log::Default->title ("AnyEvent::Log::Default"); 516 for $LOG, $FILTER, $COLLECT;
471 $AnyEvent::Log::Default->log_cb (sub {
472 warn shift;
473 0
474 });
475 $CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
476 517
477 $AnyEvent::Log::Root->parents ($AnyEvent::Log::Default); 518 $LOG->slaves;
478 $AnyEvent::Log::Root->title ("AnyEvent::Log::Root"); 519 $LOG->title ('$AnyEvent::Log::LOG');
520 $LOG->log_to_warn;
521
522 $FILTER->slaves ($LOG);
523 $FILTER->title ('$AnyEvent::Log::FILTER');
479 $AnyEvent::Log::Root->level ($AnyEvent::VERBOSE); 524 $FILTER->level ($AnyEvent::VERBOSE);
480 $CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
481 525
482 $AnyEvent::Log::Top->parents ($AnyEvent::Log::Root); 526 $COLLECT->slaves ($FILTER);
483 $AnyEvent::Log::Top->title ("AnyEvent::Log::Top"); 527 $COLLECT->title ('$AnyEvent::Log::COLLECT');
484 $CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $AnyEvent::Log::Top;
485 528
486 _reassess; 529 _reassess;
487} 530}
488 531
489# create the default logger contexts 532# create the default logger contexts
490$AnyEvent::Log::Default = ctx undef; 533$LOG = ctx undef;
491$AnyEvent::Log::Root = ctx undef; 534$FILTER = ctx undef;
492$AnyEvent::Log::Top = ctx undef; 535$COLLECT = ctx undef;
493 536
494AnyEvent::Log::reset; 537AnyEvent::Log::reset;
495 538
496# hello, CPAN, please catch me 539# hello, CPAN, please catch me
497package AnyEvent::Log::Default;
498package AE::Log::Default;
499package AnyEvent::Log::Root;
500package AE::Log::Root;
501package AnyEvent::Log::Top; 540package AnyEvent::Log::LOG;
502package AE::Log::Top; 541package AE::Log::LOG;
542package AnyEvent::Log::FILTER;
543package AE::Log::FILTER;
544package AnyEvent::Log::COLLECT;
545package AE::Log::COLLECT;
503 546
504package AnyEvent::Log::Ctx; 547package AnyEvent::Log::Ctx;
505 548
506# 0 1 2 3 4 549# 0 1 2 3 4
507# [$title, $level, %$parents, &$logcb, &$fmtcb] 550# [$title, $level, %$slaves, &$logcb, &$fmtcb]
508 551
509=item $ctx = new AnyEvent::Log::Ctx methodname => param... 552=item $ctx = new AnyEvent::Log::Ctx methodname => param...
510 553
511This is a convenience constructor that makes it simpler to construct 554This is a convenience constructor that makes it simpler to construct
512anonymous logging contexts. 555anonymous logging contexts.
515name as the key with the value as parameter, unless the value is an 558name as the key with the value as parameter, unless the value is an
516arrayref, in which case it calls the method with the contents of the 559arrayref, in which case it calls the method with the contents of the
517array. The methods are called in the same order as specified. 560array. The methods are called in the same order as specified.
518 561
519Example: create a new logging context and set both the default logging 562Example: create a new logging context and set both the default logging
520level, some parent contexts and a logging callback. 563level, some slave contexts and a logging callback.
521 564
522 $ctx = new AnyEvent::Log::Ctx 565 $ctx = new AnyEvent::Log::Ctx
523 title => "dubious messages", 566 title => "dubious messages",
524 level => "error", 567 level => "error",
525 log_cb => sub { print STDOUT shift; 0 }, 568 log_cb => sub { print STDOUT shift; 0 },
526 parents => [$ctx1, $ctx, $ctx2], 569 slaves => [$ctx1, $ctx, $ctx2],
527 ; 570 ;
528 571
529=back 572=back
530 573
531=cut 574=cut
644 AnyEvent::Log::_reassess; 687 AnyEvent::Log::_reassess;
645} 688}
646 689
647=back 690=back
648 691
649=head3 PARENT CONTEXTS 692=head3 SLAVE CONTEXTS
650 693
651The following methods attach and detach another logging context to a 694The following methods attach and detach another logging context to a
652logging context. 695logging context.
653 696
654Log messages are propagated to all parent contexts, unless the logging 697Log messages are propagated to all slave contexts, unless the logging
655callback consumes the message. 698callback consumes the message.
656 699
657=over 4 700=over 4
658 701
659=item $ctx->attach ($ctx2[, $ctx3...]) 702=item $ctx->attach ($ctx2[, $ctx3...])
660 703
661Attaches the given contexts as parents to this context. It is not an error 704Attaches the given contexts as slaves to this context. It is not an error
662to add a context twice (the second add will be ignored). 705to add a context twice (the second add will be ignored).
663 706
664A context can be specified either as package name or as a context object. 707A context can be specified either as package name or as a context object.
665 708
666=item $ctx->detach ($ctx2[, $ctx3...]) 709=item $ctx->detach ($ctx2[, $ctx3...])
667 710
668Removes the given parents from this context - it's not an error to attempt 711Removes the given slaves from this context - it's not an error to attempt
669to remove a context that hasn't been added. 712to remove a context that hasn't been added.
670 713
671A context can be specified either as package name or as a context object. 714A context can be specified either as package name or as a context object.
672 715
673=item $ctx->parents ($ctx2[, $ctx3...]) 716=item $ctx->slaves ($ctx2[, $ctx3...])
674 717
675Replaces all parents attached to this context by the ones given. 718Replaces all slaves attached to this context by the ones given.
676 719
677=cut 720=cut
678 721
679sub attach { 722sub attach {
680 my $ctx = shift; 723 my $ctx = shift;
688 731
689 delete $ctx->[2]{$_+0} 732 delete $ctx->[2]{$_+0}
690 for map { AnyEvent::Log::ctx $_ } @_; 733 for map { AnyEvent::Log::ctx $_ } @_;
691} 734}
692 735
693sub parents { 736sub slaves {
694 undef $_[0][2]; 737 undef $_[0][2];
695 &attach; 738 &attach;
696} 739}
697 740
698=back 741=back
699 742
700=head3 MESSAGE LOGGING 743=head3 LOG TARGETS
701 744
702The following methods configure how the logging context actually does 745The following methods configure how the logging context actually does
703the logging (which consists of formatting the message and printing it or 746the logging (which consists of formatting the message and printing it or
704whatever it wants to do with it) and also allows you to log messages 747whatever it wants to do with it).
705directly to a context, without going via your package context.
706 748
707=over 4 749=over 4
708 750
709=item $ctx->log_cb ($cb->($str)) 751=item $ctx->log_cb ($cb->($str)
710 752
711Replaces the logging callback on the context (C<undef> disables the 753Replaces the logging callback on the context (C<undef> disables the
712logging callback). 754logging callback).
713 755
714The logging callback is responsible for handling formatted log messages 756The logging callback is responsible for handling formatted log messages
715(see C<fmt_cb> below) - normally simple text strings that end with a 757(see C<fmt_cb> below) - normally simple text strings that end with a
716newline (and are possibly multiline themselves). 758newline (and are possibly multiline themselves).
717 759
718It also has to return true iff it has consumed the log message, and false 760It also has to return true iff it has consumed the log message, and false
719if it hasn't. Consuming a message means that it will not be sent to any 761if it hasn't. Consuming a message means that it will not be sent to any
720parent context. When in doubt, return C<0> from your logging callback. 762slave context. When in doubt, return C<0> from your logging callback.
721 763
722Example: a very simple logging callback, simply dump the message to STDOUT 764Example: a very simple logging callback, simply dump the message to STDOUT
723and do not consume it. 765and do not consume it.
724 766
725 $ctx->log_cb (sub { print STDERR shift; 0 }); 767 $ctx->log_cb (sub { print STDERR shift; 0 });
733your program. 775your program.
734 776
735 $ctx->levels ("debug", "trace"); 777 $ctx->levels ("debug", "trace");
736 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages 778 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
737 779
738=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message)) 780=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
739 781
740Replaces the formatting callback on the context (C<undef> restores the 782Replaces the formatting callback on the context (C<undef> restores the
741default formatter). 783default formatter).
742 784
743The callback is passed the (possibly fractional) timestamp, the original 785The callback is passed the (possibly fractional) timestamp, the original
744logging context, the (numeric) logging level and the raw message string and needs to 786logging context, the (numeric) logging level and the raw message string
745return a formatted log message. In most cases this will be a string, but 787and needs to return a formatted log message. In most cases this will be a
746it could just as well be an array reference that just stores the values. 788string, but it could just as well be an array reference that just stores
789the values.
790
791If, for some reason, you want to use C<caller> to find out more baout the
792logger then you should walk up the call stack until you are no longer
793inside the C<AnyEvent::Log> package.
747 794
748Example: format just the raw message, with numeric log level in angle 795Example: format just the raw message, with numeric log level in angle
749brackets. 796brackets.
750 797
751 $ctx->fmt_cb (sub { 798 $ctx->fmt_cb (sub {
768 "$msg->[3]"; 815 "$msg->[3]";
769 816
770 0 817 0
771 }); 818 });
772 819
820=item $ctx->log_to_warn
821
822Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
823(usually this logs to STDERR).
824
825=item $ctx->log_to_file ($path)
826
827Sets the C<log_cb> to log to a file (by appending), unbuffered.
828
829=item $ctx->log_to_path ($path)
830
831Same as C<< ->log_to_file >>, but opens the file for each message. This
832is much slower, but allows you to change/move/rename/delete the file at
833basically any time.
834
835Needless(?) to say, if you do not want to be bitten by some evil person
836calling C<chdir>, the path should be absolute. Doesn't help with
837C<chroot>, but hey...
838
839=item $ctx->log_to_syslog ([$log_flags])
840
841Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
842the others in the obvious way. If specified, then the C<$log_flags> are
843simply or'ed onto the priority argument and can contain any C<LOG_xxx>
844flags valid for Sys::Syslog::syslog, except for the priority levels.
845
846Note that this function also sets a C<fmt_cb> - the logging part requires
847an array reference with [$level, $str] as input.
848
773=cut 849=cut
774 850
775sub log_cb { 851sub log_cb {
776 my ($ctx, $cb) = @_; 852 my ($ctx, $cb) = @_;
777 853
782 my ($ctx, $cb) = @_; 858 my ($ctx, $cb) = @_;
783 859
784 $ctx->[4] = $cb; 860 $ctx->[4] = $cb;
785} 861}
786 862
787=item $ctx->log ($level, $msg[, @params]) 863sub log_to_warn {
864 my ($ctx, $path) = @_;
788 865
789Same as C<AnyEvent::Log::log>, but uses the given context as log context. 866 $ctx->log_cb (sub {
867 warn shift;
868 0
869 });
870}
790 871
791=item $logger = $ctx->logger ($level[, \$enabled]) 872sub log_to_file {
792 873 my ($ctx, $path) = @_;
793Same as C<AnyEvent::Log::logger>, but uses the given context as log
794context.
795
796=cut
797
798*log = \&AnyEvent::Log::_log;
799*logger = \&AnyEvent::Log::_logger;
800
8011;
802
803=back
804
805=head1 EXAMPLES
806
807This section shows some common configurations.
808
809=over 4
810
811=item Setting the global logging level.
812
813Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
814running your program, or modify the log level of the root context:
815
816 PERL_ANYEVENT_VERBOSE=5 ./myprog
817
818 $AnyEvent::Log::Root->level ("warn");
819
820=item Append all messages to a file instead of sending them to STDERR.
821
822This is affected by the global logging level.
823 874
824 open my $fh, ">>", $path 875 open my $fh, ">>", $path
825 or die "$path: $!"; 876 or die "$path: $!";
826 877
827 $AnyEvent::Log::Default->log_cb (sub { 878 $ctx->log_cb (sub {
828 syswrite $fh, shift; 879 syswrite $fh, shift;
829 0 880 0
830 }); 881 });
882}
883
884sub log_to_path {
885 my ($ctx, $path) = @_;
886
887 $ctx->log_cb (sub {
888 open my $fh, ">>", $path
889 or die "$path: $!";
890
891 syswrite $fh, shift;
892 0
893 });
894}
895
896sub log_to_syslog {
897 my ($ctx, $flags) = @_;
898
899 require Sys::Syslog;
900
901 $ctx->fmt_cb (sub {
902 my $str = $_[3];
903 $str =~ s/\n(?=.)/\n+ /g;
904
905 [$_[2], "($_[1][0]) $str"]
906 });
907
908 $ctx->log_cb (sub {
909 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
910
911 Sys::Syslog::syslog ($flags | ($lvl - 1), $_)
912 for split /\n/, $_[0][1];
913
914 0
915 });
916}
917
918=back
919
920=head3 MESSAGE LOGGING
921
922These methods allow you to log messages directly to a context, without
923going via your package context.
924
925=over 4
926
927=item $ctx->log ($level, $msg[, @params])
928
929Same as C<AnyEvent::Log::log>, but uses the given context as log context.
930
931=item $logger = $ctx->logger ($level[, \$enabled])
932
933Same as C<AnyEvent::Log::logger>, but uses the given context as log
934context.
935
936=cut
937
938*log = \&AnyEvent::Log::_log;
939*logger = \&AnyEvent::Log::_logger;
940
941=back
942
943=cut
944
945package AnyEvent::Log;
946
947=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
948
949Logging can also be configured by setting the environment variable
950C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
951
952The value consists of one or more logging context specifications separated
953by C<:> or whitespace. Each logging specification in turn starts with a
954context name, followed by C<=>, followed by zero or more comma-separated
955configuration directives, here are some examples:
956
957 # set default logging level
958 filter=warn
959
960 # log to file instead of to stderr
961 log=file=/tmp/mylog
962
963 # log to file in addition to stderr
964 log=+%file:%file=file=/tmp/mylog
965
966 # enable debug log messages, log warnings and above to syslog
967 filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
968
969 # log trace messages (only) from AnyEvent::Debug to file
970 AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
971
972A context name in the log specification can be any of the following:
973
974=over 4
975
976=item C<collect>, C<filter>, C<log>
977
978Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
979C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
980
981=item C<%name>
982
983Context names starting with a C<%> are anonymous contexts created when the
984name is first mentioned. The difference to package contexts is that by
985default they have no attached slaves.
986
987=item a perl package name
988
989Any other string references the logging context associated with the given
990Perl C<package>. In the unlikely case where you want to specify a package
991context that matches on of the other context name forms, you can add a
992C<::> to the package name to force interpretation as a package.
993
994=back
995
996The configuration specifications can be any number of the following:
997
998=over 4
999
1000=item C<stderr>
1001
1002Configures the context to use Perl's C<warn> function (which typically
1003logs to C<STDERR>). Works like C<log_to_warn>.
1004
1005=item C<file=>I<path>
1006
1007Configures the context to log to a file with the given path. Works like
1008C<log_to_file>.
1009
1010=item C<path=>I<path>
1011
1012Configures the context to log to a file with the given path. Works like
1013C<log_to_path>.
1014
1015=item C<syslog> or C<syslog=>I<expr>
1016
1017Configured the context to log to syslog. If I<expr> is given, then it is
1018evaluated in the L<Sys::Syslog> package, so you could use:
1019
1020 log=syslog=LOG_LOCAL0
1021
1022=item C<nolog>
1023
1024Configures the context to not log anything by itself, which is the
1025default. Same as C<< $ctx->log_cb (undef) >>.
1026
1027=item C<0> or C<off>
1028
1029Sets the logging level of the context ot C<0>, i.e. all messages will be
1030filtered out.
1031
1032=item C<all>
1033
1034Enables all logging levels, i.e. filtering will effectively be switched
1035off (the default).
1036
1037=item C<only>
1038
1039Disables all logging levels, and changes the interpretation of following
1040level specifications to enable the specified level only.
1041
1042Example: only enable debug messages for a context.
1043
1044 context=only,debug
1045
1046=item C<except>
1047
1048Enables all logging levels, and changes the interpretation of following
1049level specifications to disable that level. Rarely used.
1050
1051Example: enable all logging levels except fatal and trace (this is rather
1052nonsensical).
1053
1054 filter=exept,fatal,trace
1055
1056=item C<level>
1057
1058Enables all logging levels, and changes the interpretation of following
1059level specifications to be "that level or any higher priority
1060message". This is the default.
1061
1062Example: log anything at or above warn level.
1063
1064 filter=warn
1065
1066 # or, more verbose
1067 filter=only,level,warn
1068
1069=item C<1>..C<9>, a logging level name (C<error>, C<debug> etc.)
1070
1071A numeric loglevel or the name of a loglevel will be interpreted according
1072to the most recent C<only>, C<except> or C<level> directive. By default,
1073specifying a logging level enables that and any higher priority messages.
1074
1075=item C<+>I<context>
1076
1077Adds/attaches the named context as slave to the context.
1078
1079=item C<+>
1080
1081A line C<+> clears the slave list form the context. Anonymous (C<%name>)
1082contexts have no slaves by default, but package contexts have the parent
1083context as slave by default.
1084
1085Example: log messages from My::Module to a file, do not send them to the
1086default log collector.
1087
1088 My::Module=+,file=/tmp/mymodulelog
1089
1090=back
1091
1092Any character can be escaped by prefixing it with a C<\> (backslash), as
1093usual, so to log to a file containing a comma, colon, backslash and space in the
1094filename, you would do this:
1095
1096 PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
1097
1098Since whitespace (which includes newlines) is allowed, it is fine to
1099specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
1100
1101 PERL_ANYEVENT_LOG="
1102 filter=warn
1103 AnyEvent::Debug=+%trace
1104 %trace=only,trace,+log
1105 " myprog
1106
1107Also, in the unlikely case when you want to concatenate specifications,
1108use whitespace as separator, as C<::> will be interpreted as part of a
1109module name, an empty spec with two separators:
1110
1111 PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
1112
1113=cut
1114
1115for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
1116 my %anon;
1117
1118 my $pkg = sub {
1119 $_[0] eq "log" ? $LOG
1120 : $_[0] eq "filter" ? $FILTER
1121 : $_[0] eq "collect" ? $COLLECT
1122 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef)
1123 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1124 : die # never reached?
1125 };
1126
1127 /\G[[:space:]]+/gc; # skip initial whitespace
1128
1129 while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
1130 my $ctx = $pkg->($1);
1131 my $level = "level";
1132
1133 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1134 for ("$1") {
1135 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1136 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1137 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1138 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
1139 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1140 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1141 } elsif ($_ eq "+" ) { $ctx->slaves;
1142 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1143 } elsif ($_ eq "all" ) { $ctx->level ("all");
1144 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1145 } elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
1146 } elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
1147 } elsif (/^\d$/ ) { $ctx->$level ($_);
1148 } elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
1149 } else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
1150 }
1151 }
1152
1153 /\G,/gc or last;
1154 }
1155
1156 /\G[:[:space:]]+/gc or last;
1157 }
1158
1159 /\G[[:space:]]+/gc; # skip trailing whitespace
1160
1161 if (/\G(.+)/g) {
1162 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1163 }
1164}
1165
11661;
1167
1168=head1 EXAMPLES
1169
1170This section shows some common configurations, both as code, and as
1171C<PERL_ANYEVENT_LOG> string.
1172
1173=over 4
1174
1175=item Setting the global logging level.
1176
1177Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
1178running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
1179the root context at runtime:
1180
1181 PERL_ANYEVENT_VERBOSE=5 ./myprog
1182
1183 PERL_ANYEVENT_LOG=log=warn
1184
1185 $AnyEvent::Log::FILTER->level ("warn");
1186
1187=item Append all messages to a file instead of sending them to STDERR.
1188
1189This is affected by the global logging level.
1190
1191 $AnyEvent::Log::LOG->log_to_file ($path);
1192
1193 PERL_ANYEVENT_LOG=log=file=/some/path
831 1194
832=item Write all messages with priority C<error> and higher to a file. 1195=item Write all messages with priority C<error> and higher to a file.
833 1196
834This writes them only when the global logging level allows it, because 1197This writes them only when the global logging level allows it, because
835it is attached to the default context which is invoked I<after> global 1198it is attached to the default context which is invoked I<after> global
836filtering. 1199filtering.
837 1200
838 open my $fh, ">>", $path 1201 $AnyEvent::Log::FILTER->attach
839 or die "$path: $!"; 1202 new AnyEvent::Log::Ctx log_to_file => $path);
840 1203
841 $AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx 1204 PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
842 log_cb => sub { syswrite $fh, shift; 0 });
843 1205
844This writes them regardless of the global logging level, because it is 1206This writes them regardless of the global logging level, because it is
845attached to the toplevel context, which receives all messages I<before> 1207attached to the toplevel context, which receives all messages I<before>
846the global filtering. 1208the global filtering.
847 1209
848 $AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx 1210 $AnyEvent::Log::COLLECT->attach (
849 log_cb => sub { syswrite $fh, shift; 0 }); 1211 new AnyEvent::Log::Ctx log_to_file => $path);
850 1212
1213 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1214
851In both cases, messages are still written to STDOUT. 1215In both cases, messages are still written to STDERR.
852 1216
853=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s). 1217=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
854 1218
855Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug> 1219Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
856context and increase the C<AnyEvent::Debug> logging level - this simply
857circumvents the global filtering for trace messages. 1220context - this simply circumvents the global filtering for trace messages.
858 1221
859 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx; 1222 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
860 $debug->attach ($AnyEvent::Log::Default); 1223 $debug->attach ($AnyEvent::Log::LOG);
861 $debug->levels ("trace"); # not "level"!
862 1224
863This of course works for any package. 1225 PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
1226
1227This of course works for any package, not just L<AnyEvent::Debug>, but
1228assumes the log level for AnyEvent::Debug hasn't been changed from the
1229default.
864 1230
865=back 1231=back
866 1232
867=head1 AUTHOR 1233=head1 AUTHOR
868 1234
869 Marc Lehmann <schmorp@schmorp.de> 1235 Marc Lehmann <schmorp@schmorp.de>
870 http://home.schmorp.de/ 1236 http://home.schmorp.de/
871 1237
872=cut 1238=cut
1239

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