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Revision 1.15 by root, Sat Aug 20 02:16:59 2011 UTC vs.
Revision 1.38 by root, Fri Aug 26 00:32:45 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 maximum 27 # set logging for the current package to errors and higher only
26 AnyEvent::Log::ctx->level ("all"); 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::ctx "")->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,
32 34 # regardless of (most) other settings
33 # disable logging for package "AnyEvent" and all packages below it 35 $AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
34 AnyEvent->AnyEvent::Log::ctx->level (0); 36 level => "critical",
35 37 log_to_syslog => 0,
36 # log everything below debug to a file, for the whole program 38 );
37 my $ctx = AnyEvent::Log::ctx;
38 $ctx->log_cb (sub { print FILE shift; 0 });
39 (AnyEvent::Log::ctx "")->add ($ctx);
40 39
41=head1 DESCRIPTION 40=head1 DESCRIPTION
42 41
43This module implements a relatively simple "logging framework". It doesn't 42This module implements a relatively simple "logging framework". It doesn't
44attempt to be "the" logging solution or even "a" logging solution for 43attempt to be "the" logging solution or even "a" logging solution for
45AnyEvent - AnyEvent simply creates logging messages internally, and this 44AnyEvent - AnyEvent simply creates logging messages internally, and this
46module 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
47using it from other modules as well. 46using it from other modules as well.
48 47
49Remember 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
50logged, 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
51starting your program, or change the logging level at runtime with 50before starting your program, or change the logging level at runtime with
52something like: 51something like:
53 52
54 use AnyEvent; 53 use AnyEvent::Log;
55 (AnyEvent::Log::ctx "")->level ("info"); 54 $AnyEvent::Log::FILTER->level ("info");
56 55
57The 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),
58but 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
59extensive enough for the most common tasks, such as logging to multiple 58extensive enough for the most common tasks, such as logging to multiple
60targets, or being able to log into a database. 59targets, or being able to log into a database.
61 60
61The module is also usable before AnyEvent itself is initialised, in which
62case some of the functionality might be reduced.
63
62The amount of documentation might indicate otherwise, but the module is 64The amount of documentation might indicate otherwise, but the runtime part
63still just 240 lines or so. 65of the module is still just below 300 lines of code.
66
67=head1 LOGGING LEVELS
68
69Logging levels in this module range from C<1> (highest priority) to C<9>
70(lowest priority). Note that the lowest numerical value is the highest
71priority, so when this document says "higher priority" it means "lower
72numerical value".
73
74Instead of specifying levels by name you can also specify them by aliases:
75
76 LVL NAME SYSLOG PERL NOTE
77 1 fatal emerg exit aborts program!
78 2 alert
79 3 critical crit
80 4 error err die
81 5 warn warning
82 6 note notice
83 7 info
84 8 debug
85 9 trace
86
87As you can see, some logging levels have multiple aliases - the first one
88is the "official" name, the second one the "syslog" name (if it differs)
89and the third one the "perl" name, suggesting that you log C<die> messages
90at C<error> priority.
91
92You can normally only log a single message at highest priority level
93(C<1>, C<fatal>), because logging a fatal message will also quit the
94program - so use it sparingly :)
95
96Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
97or C<all> - these are only valid in the methods they are documented for.
64 98
65=head1 LOGGING FUNCTIONS 99=head1 LOGGING FUNCTIONS
66 100
67These functions allow you to log messages. They always use the caller's 101These functions allow you to log messages. They always use the caller's
68package as a "logging module/source". Also, the main logging function is 102package as a "logging context". Also, the main logging function C<log> is
69callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is 103callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
70loaded. 104loaded.
71 105
72=over 4 106=over 4
73 107
77 111
78use Carp (); 112use Carp ();
79use POSIX (); 113use POSIX ();
80 114
81use AnyEvent (); BEGIN { AnyEvent::common_sense } 115use AnyEvent (); BEGIN { AnyEvent::common_sense }
82use AnyEvent::Util (); 116#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
83 117
84our $VERSION = $AnyEvent::VERSION; 118our $VERSION = $AnyEvent::VERSION;
119
120our ($COLLECT, $FILTER, $LOG);
85 121
86our ($now_int, $now_str1, $now_str2); 122our ($now_int, $now_str1, $now_str2);
87 123
88# Format Time, not public - yet? 124# Format Time, not public - yet?
89sub ft($) { 125sub ft($) {
94 if $now_int != $i; 130 if $now_int != $i;
95 131
96 "$now_str1$f$now_str2" 132 "$now_str1$f$now_str2"
97} 133}
98 134
99our %CTX; # all logging contexts 135our %CTX; # all package contexts
100 136
101# creates a default package context object for the given package 137# creates a default package context object for the given package
102sub _pkg_ctx($) { 138sub _pkg_ctx($) {
103 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx"; 139 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
104 140
105 # link "parent" package 141 # link "parent" package
106 my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top"; 142 my $parent = $_[0] =~ /^(.+)::/
143 ? $CTX{$1} ||= &_pkg_ctx ("$1")
144 : $COLLECT;
107 145
108 $pkg = $CTX{$pkg} ||= &_pkg_ctx ($pkg);
109 $ctx->[2]{$pkg+0} = $pkg; 146 $ctx->[2]{$parent+0} = $parent;
110 147
111 $ctx 148 $ctx
112} 149}
113 150
114=item AnyEvent::Log::log $level, $msg[, @args] 151=item AnyEvent::Log::log $level, $msg[, @args]
115 152
116Requests logging of the given C<$msg> with the given log level (1..9). 153Requests logging of the given C<$msg> with the given log level, and
117You can also use the following strings as log level: C<fatal> (1), 154returns true if the message was logged I<somewhere>.
118C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
119C<info> (7), C<debug> (8), C<trace> (9).
120 155
121For C<fatal> log levels, the program will abort. 156For C<fatal> log levels, the program will abort.
122 157
123If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the 158If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
124C<$msg> is interpreted as an sprintf format string. 159C<$msg> is interpreted as an sprintf format string.
130supposed to return the message. It will be called only then the message 165supposed to return the message. It will be called only then the message
131actually gets logged, which is useful if it is costly to create the 166actually gets logged, which is useful if it is costly to create the
132message in the first place. 167message in the first place.
133 168
134Whether the given message will be logged depends on the maximum log level 169Whether the given message will be logged depends on the maximum log level
135and the caller's package. 170and the caller's package. The return value can be used to ensure that
171messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
172runtime error it tries to log it at C<die> level, but if that message is
173lost it simply uses warn.
136 174
137Note that you can (and should) call this function as C<AnyEvent::log> or 175Note that you can (and should) call this function as C<AnyEvent::log> or
138C<AE::log>, without C<use>-ing this module if possible (i.e. you don't 176C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
139need any additional functionality), as those functions will load the 177need any additional functionality), as those functions will load the
140logging module on demand only. They are also much shorter to write. 178logging module on demand only. They are also much shorter to write.
157 195
158=cut 196=cut
159 197
160# also allow syslog equivalent names 198# also allow syslog equivalent names
161our %STR2LEVEL = ( 199our %STR2LEVEL = (
162 fatal => 1, emerg => 1, 200 fatal => 1, emerg => 1, exit => 1,
163 alert => 2, 201 alert => 2,
164 critical => 3, crit => 3, 202 critical => 3, crit => 3,
165 error => 4, err => 4, 203 error => 4, err => 4, die => 4,
166 warn => 5, warning => 5, 204 warn => 5, warning => 5,
167 note => 6, notice => 6, 205 note => 6, notice => 6,
168 info => 7, 206 info => 7,
169 debug => 8, 207 debug => 8,
170 trace => 9, 208 trace => 9,
171); 209);
172 210
173sub now () { time } 211our $TIME_EXACT;
212
213sub exact_time($) {
214 $TIME_EXACT = shift;
215 *_ts = $AnyEvent::MODEL
216 ? $TIME_EXACT ? \&AE::now : \&AE::time
217 : sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
218}
219
220BEGIN {
221 exact_time 0;
222}
174 223
175AnyEvent::post_detect { 224AnyEvent::post_detect {
176 *now = \&AE::now; 225 exact_time $TIME_EXACT;
177}; 226};
178 227
179our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace); 228our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
180 229
181# time, ctx, level, msg 230# time, ctx, level, msg
200 ? $level+0 249 ? $level+0
201 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 250 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
202 251
203 my $mask = 1 << $level; 252 my $mask = 1 << $level;
204 253
205 my (%seen, @ctx, $now, $fmt); 254 my ($success, %seen, @ctx, $now, $fmt);
206 255
207 do 256 do
208 { 257 {
209 # skip if masked 258 # skip if masked
210 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) { 259 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
214 # now get raw message, unless we have it already 263 # now get raw message, unless we have it already
215 unless ($now) { 264 unless ($now) {
216 $format = $format->() if ref $format; 265 $format = $format->() if ref $format;
217 $format = sprintf $format, @args if @args; 266 $format = sprintf $format, @args if @args;
218 $format =~ s/\n$//; 267 $format =~ s/\n$//;
219 $now = AE::now; 268 $now = _ts;
220 }; 269 };
221 270
222 # format msg 271 # format msg
223 my $str = $ctx->[4] 272 my $str = $ctx->[4]
224 ? $ctx->[4]($now, $_[0], $level, $format) 273 ? $ctx->[4]($now, $_[0], $level, $format)
225 : $fmt ||= _format $now, $_[0], $level, $format; 274 : ($fmt ||= _format $now, $_[0], $level, $format);
226 275
276 $success = 1;
277
227 $ctx->[3]($str); 278 $ctx->[3]($str)
279 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
280 } else {
281 push @ctx, values %{ $ctx->[2] }; # not masked - propagate
228 } 282 }
229
230 # not masked, not consumed - propagate to parent contexts
231 push @ctx, values %{ $ctx->[2] };
232 } 283 }
233 } 284 }
234 while $ctx = pop @ctx; 285 while $ctx = pop @ctx;
235 286
236 exit 1 if $level <= 1; 287 exit 1 if $level <= 1;
288
289 $success
237} 290}
238 291
239sub log($$;@) { 292sub log($$;@) {
240 _log 293 _log
241 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 294 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
245*AnyEvent::log = *AE::log = \&log; 298*AnyEvent::log = *AE::log = \&log;
246 299
247=item $logger = AnyEvent::Log::logger $level[, \$enabled] 300=item $logger = AnyEvent::Log::logger $level[, \$enabled]
248 301
249Creates a code reference that, when called, acts as if the 302Creates a code reference that, when called, acts as if the
250C<AnyEvent::Log::log> function was called at this point with the givne 303C<AnyEvent::Log::log> function was called at this point with the given
251level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with 304level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
252the C<AnyEvent::Log::log> function: 305the C<AnyEvent::Log::log> function:
253 306
254 my $debug_log = AnyEvent::Log::logger "debug"; 307 my $debug_log = AnyEvent::Log::logger "debug";
255 308
280 # and later in your program 333 # and later in your program
281 $debug_log->("yo, stuff here") if $debug; 334 $debug_log->("yo, stuff here") if $debug;
282 335
283 $debug and $debug_log->("123"); 336 $debug and $debug_log->("123");
284 337
285Note: currently the enabled var is always true - that will be fixed in a
286future version :)
287
288=cut 338=cut
289 339
290our %LOGGER; 340our %LOGGER;
291 341
292# re-assess logging status for all loggers 342# re-assess logging status for all loggers
293sub _reassess { 343sub _reassess {
344 local $SIG{__DIE__};
345 my $die = sub { die };
346
294 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) { 347 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
295 my ($ctx, $level, $renabled) = @$_; 348 my ($ctx, $level, $renabled) = @$_;
296 349
297 # to detect whether a message would be logged, we # actually 350 # to detect whether a message would be logged, we actually
298 # try to log one and die. this isn't fast, but we can be 351 # try to log one and die. this isn't fast, but we can be
299 # sure that the logging decision is correct :) 352 # sure that the logging decision is correct :)
300 353
301 $$renabled = !eval { 354 $$renabled = !eval {
302 local $SIG{__DIE__};
303
304 _log $ctx, $level, sub { die }; 355 _log $ctx, $level, $die;
305 356
306 1 357 1
307 }; 358 };
308
309 $$renabled = 1; # TODO
310 } 359 }
311} 360}
312 361
313sub _logger { 362sub _logger {
314 my ($ctx, $level, $renabled) = @_; 363 my ($ctx, $level, $renabled) = @_;
319 368
320 $LOGGER{$logger+0} = $logger; 369 $LOGGER{$logger+0} = $logger;
321 370
322 _reassess $logger+0; 371 _reassess $logger+0;
323 372
373 require AnyEvent::Util;
324 my $guard = AnyEvent::Util::guard { 374 my $guard = AnyEvent::Util::guard (sub {
325 # "clean up" 375 # "clean up"
326 delete $LOGGER{$logger+0}; 376 delete $LOGGER{$logger+0};
327 }; 377 });
328 378
329 sub { 379 sub {
330 $guard if 0; # keep guard alive, but don't cause runtime overhead 380 $guard if 0; # keep guard alive, but don't cause runtime overhead
331 381
332 _log $ctx, $level, @_ 382 _log $ctx, $level, @_
337sub logger($;$) { 387sub logger($;$) {
338 _logger 388 _logger
339 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 389 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
340 @_ 390 @_
341} 391}
392
393=item AnyEvent::Log::exact_time $on
394
395By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
396eventloop time, for the log timestamps. After calling this function with a
397true value it will instead resort to C<AE::time>, i.e. fetch the current
398time on each log message. This only makes a difference for event loops
399that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
400
401Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
402initialised, this switch will also decide whether to use C<CORE::time> or
403C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
404available.
342 405
343=back 406=back
344 407
345=head1 LOGGING CONTEXTS 408=head1 LOGGING CONTEXTS
346 409
359timestamp, context, level and string message and formats it in the way 422timestamp, context, level and string message and formats it in the way
360it should be logged) and a logging callback (which is responsible for 423it should be logged) and a logging callback (which is responsible for
361actually logging the formatted message and telling C<AnyEvent::Log> 424actually logging the formatted message and telling C<AnyEvent::Log>
362whether it has consumed the message, or whether it should be propagated). 425whether it has consumed the message, or whether it should be propagated).
363 426
364For propagation, a context can have any number of attached I<parent 427For propagation, a context can have any number of attached I<slave
365contexts>. Any message that is neither masked by the logging mask nor 428contexts>. Any message that is neither masked by the logging mask nor
366masked by the logging callback returning true will be passed to all parent 429masked by the logging callback returning true will be passed to all slave
367contexts. 430contexts.
368 431
369Each call to a logging function will log the message at most once per 432Each call to a logging function will log the message at most once per
370context, so it does not matter (much) if there are cycles or if the 433context, so it does not matter (much) if there are cycles or if the
371message can arrive at the same context via multiple paths. 434message can arrive at the same context via multiple paths.
375By default, all logging contexts have an full set of log levels ("all"), a 438By default, all logging contexts have an full set of log levels ("all"), a
376disabled logging callback and the default formatting callback. 439disabled logging callback and the default formatting callback.
377 440
378Package contexts have the package name as logging title by default. 441Package contexts have the package name as logging title by default.
379 442
380They have exactly one parent - the context of the "parent" package. The 443They have exactly one slave - the context of the "parent" package. The
381parent package is simply defined to be the package name without the last 444parent package is simply defined to be the package name without the last
382component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>, 445component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
383and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the 446and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
384exception of the rule - just like the parent of any package name in 447exception of the rule - just like the "parent" of any single-component
385Perl is C<main>, the default parent of any top-level package context is 448package name in Perl is C<main>, the default slave of any top-level
386C<AnyEvent::Log::Top>. 449package context is C<$AnyEvent::Log::COLLECT>.
387 450
388Since perl packages form only an approximate hierarchy, this parent 451Since perl packages form only an approximate hierarchy, this slave
389context can of course be removed. 452context can of course be removed.
390 453
391All other (anonymous) contexts have no parents and an empty title by 454All other (anonymous) contexts have no slaves and an empty title by
392default. 455default.
393 456
394When the module is loaded it creates the default context called 457When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
395C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>), 458context that simply logs everything via C<warn>, without propagating
396which simply logs everything via C<warn> and doesn't propagate anything
397anywhere by default. The purpose of the default context is to provide 459anything anywhere by default. The purpose of this context is to provide
398a convenient place to override the global logging target or to attach 460a convenient place to override the global logging target or to attach
399additional log targets. It's not meant for filtering. 461additional log targets. It's not meant for filtering.
400 462
401It then creates the root context called C<AnyEvent::Log::Root> (also 463It then creates the C<$AnyEvent::Log::FILTER> context whose
402stored in C<$AnyEvent::Log::Root>) and sets its log level set to all 464purpose is to suppress all messages with priority higher
403levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It 465than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
404then attached the default logging context to it. The purpose of the root 466C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
405context is to simply provide filtering according to some global log level. 467is to simply provide filtering according to some global log level.
406 468
407Finally it creates the top-level package context called 469Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
408C<AnyEvent::Log::Top> (also stored in, you might have guessed, 470and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
409C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
410it at default config. It's purpose is simply to collect all log messages 471leaves it at default config. Its purpose is simply to collect all log
411system-wide. 472messages system-wide.
412 473
413These three special contexts can also be referred to by the 474The hierarchy is then:
414package/context names C<AE::Log::Default>, C<AE::Log::Root> and
415C<AE::Log::Top>.
416 475
476 any package, eventually -> $COLLECT -> $FILTER -> $LOG
477
417The effect of all this is that log messages, by default, wander up 478The effect of all this is that log messages, by default, wander up to the
418to the root context where log messages with lower priority then 479C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
480from there to C<$AnyEvent::Log::FILTER> where log messages with lower
419C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the 481priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
420AnyEvent::Log::Default context to be passed to C<warn>. 482to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
421 483
422Splitting the top level context into three contexts makes it easy to set 484This makes it easy to set a global logging level (by modifying $FILTER),
423a global logging level (by modifying the root context), but still allow 485but still allow other contexts to send, for example, their debug and trace
424other contexts to log, for example, their debug and trace messages to the
425default target despite the global logging level, or to attach additional 486messages to the $LOG target despite the global logging level, or to attach
426log targets that log messages, regardless of the global logging level. 487additional log targets that log messages, regardless of the global logging
488level.
427 489
428It also makes it easy to replace the default warn-logger by something that 490It also makes it easy to modify the default warn-logger ($LOG) to
429logs to a file, or to attach additional logging targets. 491something that logs to a file, or to attach additional logging targets
492(such as loggign to a file) by attaching it to $FILTER.
430 493
431=head2 CREATING/FINDING/DESTROYING CONTEXTS 494=head2 CREATING/FINDING/DESTROYING CONTEXTS
432 495
433=over 4 496=over 4
434 497
456 : bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx" 519 : bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
457} 520}
458 521
459=item AnyEvent::Log::reset 522=item AnyEvent::Log::reset
460 523
461Resets all package contexts contexts and recreates the default hierarchy 524Resets all package contexts and recreates the default hierarchy if
462if necessary, i.e. resets the logging subsystem to defaults. 525necessary, i.e. resets the logging subsystem to defaults, as much as
526possible. This process keeps references to contexts held by other parts of
527the program intact.
463 528
464This can be used to implement config-file (re-)loading: before loading a 529This can be used to implement config-file (re-)loading: before loading a
465configuration, reset all contexts. 530configuration, reset all contexts.
466 531
467Note that this currently destroys all logger callbacks - bug me if you
468need this fixed :)
469
470=cut 532=cut
471 533
472sub reset { 534sub reset {
473 # hard to kill complex data structures 535 # hard to kill complex data structures
474 # we recreate all package loggers and reset the hierarchy 536 # we "recreate" all package loggers and reset the hierarchy
475 while (my ($k, $v) = each %CTX) { 537 while (my ($k, $v) = each %CTX) {
476 @$v = ($k, (1 << 10) - 1 - 1, { }); 538 @$v = ($k, (1 << 10) - 1 - 1, { });
477 539
478 my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top"; 540 $v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
479 $v->attach ($CTX{$pkg});
480 } 541 }
481 542
482 $AnyEvent::Log::Default->parents; 543 @$_ = ($_->[0], (1 << 10) - 1 - 1)
483 $AnyEvent::Log::Default->title ("AnyEvent::Log::Default"); 544 for $LOG, $FILTER, $COLLECT;
484 $AnyEvent::Log::Default->log_cb (sub {
485 warn shift;
486 0
487 });
488 $CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
489 545
490 $AnyEvent::Log::Root->parents ($AnyEvent::Log::Default); 546 #$LOG->slaves;
491 $AnyEvent::Log::Root->title ("AnyEvent::Log::Root"); 547 $LOG->title ('$AnyEvent::Log::LOG');
548 $LOG->log_to_warn;
549
550 $FILTER->slaves ($LOG);
551 $FILTER->title ('$AnyEvent::Log::FILTER');
492 $AnyEvent::Log::Root->level ($AnyEvent::VERBOSE); 552 $FILTER->level ($AnyEvent::VERBOSE);
493 $CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
494 553
495 $AnyEvent::Log::Top->parents ($AnyEvent::Log::Root); 554 $COLLECT->slaves ($FILTER);
496 $AnyEvent::Log::Top->title ("AnyEvent::Log::Top"); 555 $COLLECT->title ('$AnyEvent::Log::COLLECT');
497 $CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $AnyEvent::Log::Top;
498 556
499 _reassess; 557 _reassess;
500} 558}
501 559
502# create the default logger contexts 560# create the default logger contexts
503$AnyEvent::Log::Default = ctx undef; 561$LOG = ctx undef;
504$AnyEvent::Log::Root = ctx undef; 562$FILTER = ctx undef;
505$AnyEvent::Log::Top = ctx undef; 563$COLLECT = ctx undef;
506 564
507AnyEvent::Log::reset; 565AnyEvent::Log::reset;
508 566
509# hello, CPAN, please catch me 567# hello, CPAN, please catch me
510package AnyEvent::Log::Default;
511package AE::Log::Default;
512package AnyEvent::Log::Root;
513package AE::Log::Root;
514package AnyEvent::Log::Top; 568package AnyEvent::Log::LOG;
515package AE::Log::Top; 569package AE::Log::LOG;
570package AnyEvent::Log::FILTER;
571package AE::Log::FILTER;
572package AnyEvent::Log::COLLECT;
573package AE::Log::COLLECT;
516 574
517package AnyEvent::Log::Ctx; 575package AnyEvent::Log::Ctx;
518 576
519# 0 1 2 3 4 577# 0 1 2 3 4
520# [$title, $level, %$parents, &$logcb, &$fmtcb] 578# [$title, $level, %$slaves, &$logcb, &$fmtcb]
521 579
522=item $ctx = new AnyEvent::Log::Ctx methodname => param... 580=item $ctx = new AnyEvent::Log::Ctx methodname => param...
523 581
524This is a convenience constructor that makes it simpler to construct 582This is a convenience constructor that makes it simpler to construct
525anonymous logging contexts. 583anonymous logging contexts.
528name as the key with the value as parameter, unless the value is an 586name as the key with the value as parameter, unless the value is an
529arrayref, in which case it calls the method with the contents of the 587arrayref, in which case it calls the method with the contents of the
530array. The methods are called in the same order as specified. 588array. The methods are called in the same order as specified.
531 589
532Example: create a new logging context and set both the default logging 590Example: create a new logging context and set both the default logging
533level, some parent contexts and a logging callback. 591level, some slave contexts and a logging callback.
534 592
535 $ctx = new AnyEvent::Log::Ctx 593 $ctx = new AnyEvent::Log::Ctx
536 title => "dubious messages", 594 title => "dubious messages",
537 level => "error", 595 level => "error",
538 log_cb => sub { print STDOUT shift; 0 }, 596 log_cb => sub { print STDOUT shift; 0 },
539 parents => [$ctx1, $ctx, $ctx2], 597 slaves => [$ctx1, $ctx, $ctx2],
540 ; 598 ;
541 599
542=back 600=back
543 601
544=cut 602=cut
657 AnyEvent::Log::_reassess; 715 AnyEvent::Log::_reassess;
658} 716}
659 717
660=back 718=back
661 719
662=head3 PARENT CONTEXTS 720=head3 SLAVE CONTEXTS
663 721
664The following methods attach and detach another logging context to a 722The following methods attach and detach another logging context to a
665logging context. 723logging context.
666 724
667Log messages are propagated to all parent contexts, unless the logging 725Log messages are propagated to all slave contexts, unless the logging
668callback consumes the message. 726callback consumes the message.
669 727
670=over 4 728=over 4
671 729
672=item $ctx->attach ($ctx2[, $ctx3...]) 730=item $ctx->attach ($ctx2[, $ctx3...])
673 731
674Attaches the given contexts as parents to this context. It is not an error 732Attaches the given contexts as slaves to this context. It is not an error
675to add a context twice (the second add will be ignored). 733to add a context twice (the second add will be ignored).
676 734
677A context can be specified either as package name or as a context object. 735A context can be specified either as package name or as a context object.
678 736
679=item $ctx->detach ($ctx2[, $ctx3...]) 737=item $ctx->detach ($ctx2[, $ctx3...])
680 738
681Removes the given parents from this context - it's not an error to attempt 739Removes the given slaves from this context - it's not an error to attempt
682to remove a context that hasn't been added. 740to remove a context that hasn't been added.
683 741
684A context can be specified either as package name or as a context object. 742A context can be specified either as package name or as a context object.
685 743
686=item $ctx->parents ($ctx2[, $ctx3...]) 744=item $ctx->slaves ($ctx2[, $ctx3...])
687 745
688Replaces all parents attached to this context by the ones given. 746Replaces all slaves attached to this context by the ones given.
689 747
690=cut 748=cut
691 749
692sub attach { 750sub attach {
693 my $ctx = shift; 751 my $ctx = shift;
701 759
702 delete $ctx->[2]{$_+0} 760 delete $ctx->[2]{$_+0}
703 for map { AnyEvent::Log::ctx $_ } @_; 761 for map { AnyEvent::Log::ctx $_ } @_;
704} 762}
705 763
706sub parents { 764sub slaves {
707 undef $_[0][2]; 765 undef $_[0][2];
708 &attach; 766 &attach;
709} 767}
710 768
711=back 769=back
712 770
713=head3 MESSAGE LOGGING 771=head3 LOG TARGETS
714 772
715The following methods configure how the logging context actually does 773The following methods configure how the logging context actually does
716the logging (which consists of formatting the message and printing it or 774the logging (which consists of formatting the message and printing it or
717whatever it wants to do with it) and also allows you to log messages 775whatever it wants to do with it).
718directly to a context, without going via your package context.
719 776
720=over 4 777=over 4
721 778
722=item $ctx->log_cb ($cb->($str)) 779=item $ctx->log_cb ($cb->($str)
723 780
724Replaces the logging callback on the context (C<undef> disables the 781Replaces the logging callback on the context (C<undef> disables the
725logging callback). 782logging callback).
726 783
727The logging callback is responsible for handling formatted log messages 784The logging callback is responsible for handling formatted log messages
728(see C<fmt_cb> below) - normally simple text strings that end with a 785(see C<fmt_cb> below) - normally simple text strings that end with a
729newline (and are possibly multiline themselves). 786newline (and are possibly multiline themselves).
730 787
731It also has to return true iff it has consumed the log message, and false 788It also has to return true iff it has consumed the log message, and false
732if it hasn't. Consuming a message means that it will not be sent to any 789if it hasn't. Consuming a message means that it will not be sent to any
733parent context. When in doubt, return C<0> from your logging callback. 790slave context. When in doubt, return C<0> from your logging callback.
734 791
735Example: a very simple logging callback, simply dump the message to STDOUT 792Example: a very simple logging callback, simply dump the message to STDOUT
736and do not consume it. 793and do not consume it.
737 794
738 $ctx->log_cb (sub { print STDERR shift; 0 }); 795 $ctx->log_cb (sub { print STDERR shift; 0 });
746your program. 803your program.
747 804
748 $ctx->levels ("debug", "trace"); 805 $ctx->levels ("debug", "trace");
749 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages 806 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
750 807
751=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message)) 808=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
752 809
753Replaces the formatting callback on the context (C<undef> restores the 810Replaces the formatting callback on the context (C<undef> restores the
754default formatter). 811default formatter).
755 812
756The callback is passed the (possibly fractional) timestamp, the original 813The callback is passed the (possibly fractional) timestamp, the original
757logging context, the (numeric) logging level and the raw message string and needs to 814logging context, the (numeric) logging level and the raw message string
758return a formatted log message. In most cases this will be a string, but 815and needs to return a formatted log message. In most cases this will be a
759it could just as well be an array reference that just stores the values. 816string, but it could just as well be an array reference that just stores
817the values.
818
819If, for some reason, you want to use C<caller> to find out more baout the
820logger then you should walk up the call stack until you are no longer
821inside the C<AnyEvent::Log> package.
760 822
761Example: format just the raw message, with numeric log level in angle 823Example: format just the raw message, with numeric log level in angle
762brackets. 824brackets.
763 825
764 $ctx->fmt_cb (sub { 826 $ctx->fmt_cb (sub {
781 "$msg->[3]"; 843 "$msg->[3]";
782 844
783 0 845 0
784 }); 846 });
785 847
848=item $ctx->log_to_warn
849
850Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
851(usually this logs to STDERR).
852
853=item $ctx->log_to_file ($path)
854
855Sets the C<log_cb> to log to a file (by appending), unbuffered.
856
857=item $ctx->log_to_path ($path)
858
859Same as C<< ->log_to_file >>, but opens the file for each message. This
860is much slower, but allows you to change/move/rename/delete the file at
861basically any time.
862
863Needless(?) to say, if you do not want to be bitten by some evil person
864calling C<chdir>, the path should be absolute. Doesn't help with
865C<chroot>, but hey...
866
867=item $ctx->log_to_syslog ([$log_flags])
868
869Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
870the others in the obvious way. If specified, then the C<$log_flags> are
871simply or'ed onto the priority argument and can contain any C<LOG_xxx>
872flags valid for Sys::Syslog::syslog, except for the priority levels.
873
874Note that this function also sets a C<fmt_cb> - the logging part requires
875an array reference with [$level, $str] as input.
876
786=cut 877=cut
787 878
788sub log_cb { 879sub log_cb {
789 my ($ctx, $cb) = @_; 880 my ($ctx, $cb) = @_;
790 881
795 my ($ctx, $cb) = @_; 886 my ($ctx, $cb) = @_;
796 887
797 $ctx->[4] = $cb; 888 $ctx->[4] = $cb;
798} 889}
799 890
800=item $ctx->log ($level, $msg[, @params]) 891sub log_to_warn {
892 my ($ctx, $path) = @_;
801 893
802Same as C<AnyEvent::Log::log>, but uses the given context as log context. 894 $ctx->log_cb (sub {
895 warn shift;
896 0
897 });
898}
803 899
804=item $logger = $ctx->logger ($level[, \$enabled]) 900sub log_to_file {
805 901 my ($ctx, $path) = @_;
806Same as C<AnyEvent::Log::logger>, but uses the given context as log
807context.
808
809=cut
810
811*log = \&AnyEvent::Log::_log;
812*logger = \&AnyEvent::Log::_logger;
813
8141;
815
816=back
817
818=head1 EXAMPLES
819
820This section shows some common configurations.
821
822=over 4
823
824=item Setting the global logging level.
825
826Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
827running your program, or modify the log level of the root context:
828
829 PERL_ANYEVENT_VERBOSE=5 ./myprog
830
831 $AnyEvent::Log::Root->level ("warn");
832
833=item Append all messages to a file instead of sending them to STDERR.
834
835This is affected by the global logging level.
836 902
837 open my $fh, ">>", $path 903 open my $fh, ">>", $path
838 or die "$path: $!"; 904 or die "$path: $!";
839 905
840 $AnyEvent::Log::Default->log_cb (sub { 906 $ctx->log_cb (sub {
841 syswrite $fh, shift; 907 syswrite $fh, shift;
842 0 908 0
843 }); 909 });
910}
911
912sub log_to_path {
913 my ($ctx, $path) = @_;
914
915 $ctx->log_cb (sub {
916 open my $fh, ">>", $path
917 or die "$path: $!";
918
919 syswrite $fh, shift;
920 0
921 });
922}
923
924sub log_to_syslog {
925 my ($ctx, $flags) = @_;
926
927 require Sys::Syslog;
928
929 $ctx->fmt_cb (sub {
930 my $str = $_[3];
931 $str =~ s/\n(?=.)/\n+ /g;
932
933 [$_[2], "($_[1][0]) $str"]
934 });
935
936 $ctx->log_cb (sub {
937 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
938
939 Sys::Syslog::syslog ($flags | ($lvl - 1), $_)
940 for split /\n/, $_[0][1];
941
942 0
943 });
944}
945
946=back
947
948=head3 MESSAGE LOGGING
949
950These methods allow you to log messages directly to a context, without
951going via your package context.
952
953=over 4
954
955=item $ctx->log ($level, $msg[, @params])
956
957Same as C<AnyEvent::Log::log>, but uses the given context as log context.
958
959=item $logger = $ctx->logger ($level[, \$enabled])
960
961Same as C<AnyEvent::Log::logger>, but uses the given context as log
962context.
963
964=cut
965
966*log = \&AnyEvent::Log::_log;
967*logger = \&AnyEvent::Log::_logger;
968
969=back
970
971=cut
972
973package AnyEvent::Log;
974
975=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
976
977Logging can also be configured by setting the environment variable
978C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
979
980The value consists of one or more logging context specifications separated
981by C<:> or whitespace. Each logging specification in turn starts with a
982context name, followed by C<=>, followed by zero or more comma-separated
983configuration directives, here are some examples:
984
985 # set default logging level
986 filter=warn
987
988 # log to file instead of to stderr
989 log=file=/tmp/mylog
990
991 # log to file in addition to stderr
992 log=+%file:%file=file=/tmp/mylog
993
994 # enable debug log messages, log warnings and above to syslog
995 filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
996
997 # log trace messages (only) from AnyEvent::Debug to file
998 AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
999
1000A context name in the log specification can be any of the following:
1001
1002=over 4
1003
1004=item C<collect>, C<filter>, C<log>
1005
1006Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
1007C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
1008
1009=item C<%name>
1010
1011Context names starting with a C<%> are anonymous contexts created when the
1012name is first mentioned. The difference to package contexts is that by
1013default they have no attached slaves.
1014
1015=item a perl package name
1016
1017Any other string references the logging context associated with the given
1018Perl C<package>. In the unlikely case where you want to specify a package
1019context that matches on of the other context name forms, you can add a
1020C<::> to the package name to force interpretation as a package.
1021
1022=back
1023
1024The configuration specifications can be any number of the following:
1025
1026=over 4
1027
1028=item C<stderr>
1029
1030Configures the context to use Perl's C<warn> function (which typically
1031logs to C<STDERR>). Works like C<log_to_warn>.
1032
1033=item C<file=>I<path>
1034
1035Configures the context to log to a file with the given path. Works like
1036C<log_to_file>.
1037
1038=item C<path=>I<path>
1039
1040Configures the context to log to a file with the given path. Works like
1041C<log_to_path>.
1042
1043=item C<syslog> or C<syslog=>I<expr>
1044
1045Configures the context to log to syslog. If I<expr> is given, then it is
1046evaluated in the L<Sys::Syslog> package, so you could use:
1047
1048 log=syslog=LOG_LOCAL0
1049
1050=item C<nolog>
1051
1052Configures the context to not log anything by itself, which is the
1053default. Same as C<< $ctx->log_cb (undef) >>.
1054
1055=item C<0> or C<off>
1056
1057Sets the logging level of the context ot C<0>, i.e. all messages will be
1058filtered out.
1059
1060=item C<all>
1061
1062Enables all logging levels, i.e. filtering will effectively be switched
1063off (the default).
1064
1065=item C<only>
1066
1067Disables all logging levels, and changes the interpretation of following
1068level specifications to enable the specified level only.
1069
1070Example: only enable debug messages for a context.
1071
1072 context=only,debug
1073
1074=item C<except>
1075
1076Enables all logging levels, and changes the interpretation of following
1077level specifications to disable that level. Rarely used.
1078
1079Example: enable all logging levels except fatal and trace (this is rather
1080nonsensical).
1081
1082 filter=exept,fatal,trace
1083
1084=item C<level>
1085
1086Enables all logging levels, and changes the interpretation of following
1087level specifications to be "that level or any higher priority
1088message". This is the default.
1089
1090Example: log anything at or above warn level.
1091
1092 filter=warn
1093
1094 # or, more verbose
1095 filter=only,level,warn
1096
1097=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
1098
1099A numeric loglevel or the name of a loglevel will be interpreted according
1100to the most recent C<only>, C<except> or C<level> directive. By default,
1101specifying a logging level enables that and any higher priority messages.
1102
1103=item C<+>I<context>
1104
1105Attaches the named context as slave to the context.
1106
1107=item C<+>
1108
1109A line C<+> detaches all contexts, i.e. clears the slave list from the
1110context. Anonymous (C<%name>) contexts have no attached slaves by default,
1111but package contexts have the parent context as slave by default.
1112
1113Example: log messages from My::Module to a file, do not send them to the
1114default log collector.
1115
1116 My::Module=+,file=/tmp/mymodulelog
1117
1118=back
1119
1120Any character can be escaped by prefixing it with a C<\> (backslash), as
1121usual, so to log to a file containing a comma, colon, backslash and some
1122spaces in the filename, you would do this:
1123
1124 PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
1125
1126Since whitespace (which includes newlines) is allowed, it is fine to
1127specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
1128
1129 PERL_ANYEVENT_LOG="
1130 filter=warn
1131 AnyEvent::Debug=+%trace
1132 %trace=only,trace,+log
1133 " myprog
1134
1135Also, in the unlikely case when you want to concatenate specifications,
1136use whitespace as separator, as C<::> will be interpreted as part of a
1137module name, an empty spec with two separators:
1138
1139 PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
1140
1141=cut
1142
1143for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
1144 my %anon;
1145
1146 my $pkg = sub {
1147 $_[0] eq "log" ? $LOG
1148 : $_[0] eq "filter" ? $FILTER
1149 : $_[0] eq "collect" ? $COLLECT
1150 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef)
1151 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1152 : die # never reached?
1153 };
1154
1155 /\G[[:space:]]+/gc; # skip initial whitespace
1156
1157 while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
1158 my $ctx = $pkg->($1);
1159 my $level = "level";
1160
1161 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1162 for ("$1") {
1163 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1164 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1165 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1166 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
1167 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1168 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1169 } elsif ($_ eq "+" ) { $ctx->slaves;
1170 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1171 } elsif ($_ eq "all" ) { $ctx->level ("all");
1172 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1173 } elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
1174 } elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
1175 } elsif (/^\d$/ ) { $ctx->$level ($_);
1176 } elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
1177 } else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
1178 }
1179 }
1180
1181 /\G,/gc or last;
1182 }
1183
1184 /\G[:[:space:]]+/gc or last;
1185 }
1186
1187 /\G[[:space:]]+/gc; # skip trailing whitespace
1188
1189 if (/\G(.+)/g) {
1190 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1191 }
1192}
1193
11941;
1195
1196=head1 EXAMPLES
1197
1198This section shows some common configurations, both as code, and as
1199C<PERL_ANYEVENT_LOG> string.
1200
1201=over 4
1202
1203=item Setting the global logging level.
1204
1205Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
1206running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
1207the root context at runtime:
1208
1209 PERL_ANYEVENT_VERBOSE=5 ./myprog
1210
1211 PERL_ANYEVENT_LOG=log=warn
1212
1213 $AnyEvent::Log::FILTER->level ("warn");
1214
1215=item Append all messages to a file instead of sending them to STDERR.
1216
1217This is affected by the global logging level.
1218
1219 $AnyEvent::Log::LOG->log_to_file ($path);
1220
1221 PERL_ANYEVENT_LOG=log=file=/some/path
844 1222
845=item Write all messages with priority C<error> and higher to a file. 1223=item Write all messages with priority C<error> and higher to a file.
846 1224
847This writes them only when the global logging level allows it, because 1225This writes them only when the global logging level allows it, because
848it is attached to the default context which is invoked I<after> global 1226it is attached to the default context which is invoked I<after> global
849filtering. 1227filtering.
850 1228
851 open my $fh, ">>", $path 1229 $AnyEvent::Log::FILTER->attach
852 or die "$path: $!"; 1230 new AnyEvent::Log::Ctx log_to_file => $path);
853 1231
854 $AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx 1232 PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
855 log_cb => sub { syswrite $fh, shift; 0 });
856 1233
857This writes them regardless of the global logging level, because it is 1234This writes them regardless of the global logging level, because it is
858attached to the toplevel context, which receives all messages I<before> 1235attached to the toplevel context, which receives all messages I<before>
859the global filtering. 1236the global filtering.
860 1237
861 $AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx 1238 $AnyEvent::Log::COLLECT->attach (
862 log_cb => sub { syswrite $fh, shift; 0 }); 1239 new AnyEvent::Log::Ctx log_to_file => $path);
863 1240
1241 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1242
864In both cases, messages are still written to STDOUT. 1243In both cases, messages are still written to STDERR.
865 1244
866=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s). 1245=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
867 1246
868Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug> 1247Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
869context and increase the C<AnyEvent::Debug> logging level - this simply
870circumvents the global filtering for trace messages. 1248context - this simply circumvents the global filtering for trace messages.
871 1249
872 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx; 1250 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
873 $debug->attach ($AnyEvent::Log::Default); 1251 $debug->attach ($AnyEvent::Log::LOG);
874 $debug->levels ("trace"); # not "level"!
875 1252
876This of course works for any package. 1253 PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
1254
1255This of course works for any package, not just L<AnyEvent::Debug>, but
1256assumes the log level for AnyEvent::Debug hasn't been changed from the
1257default.
877 1258
878=back 1259=back
879 1260
880=head1 AUTHOR 1261=head1 AUTHOR
881 1262
882 Marc Lehmann <schmorp@schmorp.de> 1263 Marc Lehmann <schmorp@schmorp.de>
883 http://home.schmorp.de/ 1264 http://home.schmorp.de/
884 1265
885=cut 1266=cut
1267

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