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Revision 1.9 by root, Fri Aug 19 19:59:53 2011 UTC vs.
Revision 1.37 by root, Thu Aug 25 06:34:11 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 #TODO: config 25Configuration (also look at the EXAMPLES section):
24 #TODO: ctx () becomes caller[0]... 26
27 # set logging for the current package to errors and higher only
28 AnyEvent::Log::ctx->level ("error");
29
30 # set logging level to suppress anything below "notice"
31 $AnyEvent::Log::FILTER->level ("notice");
32
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 );
25 39
26=head1 DESCRIPTION 40=head1 DESCRIPTION
27 41
28This module implements a relatively simple "logging framework". It doesn't 42This module implements a relatively simple "logging framework". It doesn't
29attempt to be "the" logging solution or even "a" logging solution for 43attempt to be "the" logging solution or even "a" logging solution for
30AnyEvent - AnyEvent simply creates logging messages internally, and this 44AnyEvent - AnyEvent simply creates logging messages internally, and this
31module 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
32using it from other modules as well. 46using it from other modules as well.
33 47
34Remember 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
35logged, ever, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number 49will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
36before starting your program, or change the logging level at runtime wiht 50before starting your program, or change the logging level at runtime with
37something like: 51something like:
38 52
39 use AnyEvent; 53 use AnyEvent::Log;
40 (AnyEvent::Log::ctx "")->level ("info"); 54 $AnyEvent::Log::FILTER->level ("info");
55
56The design goal behind this module was to keep it simple (and small),
57but make it powerful enough to be potentially useful for any module, and
58extensive enough for the most common tasks, such as logging to multiple
59targets, or being able to log into a database.
60
61The module is also usable before AnyEvent itself is initialised, in which
62case some of the functionality might be reduced.
63
64The amount of documentation might indicate otherwise, but the runtime part
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.
41 98
42=head1 LOGGING FUNCTIONS 99=head1 LOGGING FUNCTIONS
43 100
44These 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
45package as a "logging module/source". Also, the main logging function is 102package as a "logging context". Also, the main logging function C<log> is
46callable 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
47loaded. 104loaded.
48 105
49=over 4 106=over 4
50 107
54 111
55use Carp (); 112use Carp ();
56use POSIX (); 113use POSIX ();
57 114
58use AnyEvent (); BEGIN { AnyEvent::common_sense } 115use AnyEvent (); BEGIN { AnyEvent::common_sense }
59use AnyEvent::Util (); 116#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
117
118our $VERSION = $AnyEvent::VERSION;
119
120our ($COLLECT, $FILTER, $LOG);
60 121
61our ($now_int, $now_str1, $now_str2); 122our ($now_int, $now_str1, $now_str2);
62 123
63# Format Time, not public - yet? 124# Format Time, not public - yet?
64sub ft($) { 125sub ft($) {
69 if $now_int != $i; 130 if $now_int != $i;
70 131
71 "$now_str1$f$now_str2" 132 "$now_str1$f$now_str2"
72} 133}
73 134
74our %CTX; # all logging contexts 135our %CTX; # all package contexts
75
76my $default_log_cb = sub { 0 };
77 136
78# creates a default package context object for the given package 137# creates a default package context object for the given package
79sub _pkg_ctx($) { 138sub _pkg_ctx($) {
80 my $ctx = bless [$_[0], 0, {}, $default_log_cb], "AnyEvent::Log::Ctx"; 139 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
81 140
82 # link "parent" package 141 # link "parent" package
83 my $pkg = $_[0] =~ /^(.+)::/ ? $1 : ""; 142 my $parent = $_[0] =~ /^(.+)::/
143 ? $CTX{$1} ||= &_pkg_ctx ("$1")
144 : $COLLECT;
84 145
85 $pkg = $CTX{$pkg} ||= &_pkg_ctx ($pkg);
86 $ctx->[2]{$pkg+0} = $pkg; 146 $ctx->[2]{$parent+0} = $parent;
87 147
88 $ctx 148 $ctx
89} 149}
90 150
91=item AnyEvent::Log::log $level, $msg[, @args] 151=item AnyEvent::Log::log $level, $msg[, @args]
92 152
93Requests logging of the given C<$msg> with the given log level (1..9). 153Requests logging of the given C<$msg> with the given log level, and
94You can also use the following strings as log level: C<fatal> (1), 154returns true if the message was logged I<somewhere>.
95C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
96C<info> (7), C<debug> (8), C<trace> (9).
97 155
98For C<fatal> log levels, the program will abort. 156For C<fatal> log levels, the program will abort.
99 157
100If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the 158If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
101C<$msg> is interpreted as an sprintf format string. 159C<$msg> is interpreted as an sprintf format string.
107supposed 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
108actually 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
109message in the first place. 167message in the first place.
110 168
111Whether 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
112and 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.
113 174
114Note 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
115C<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
116need any additional functionality), as those functions will load the 177need any additional functionality), as those functions will load the
117logging module on demand only. They are also much shorter to write. 178logging module on demand only. They are also much shorter to write.
118 179
119Also, if you otpionally generate a lot of debug messages (such as when 180Also, if you optionally generate a lot of debug messages (such as when
120tracing some code), you should look into using a logger callback and a 181tracing some code), you should look into using a logger callback and a
121boolean enabler (see C<logger>, below). 182boolean enabler (see C<logger>, below).
122 183
123Example: log something at error level. 184Example: log something at error level.
124 185
134 195
135=cut 196=cut
136 197
137# also allow syslog equivalent names 198# also allow syslog equivalent names
138our %STR2LEVEL = ( 199our %STR2LEVEL = (
139 fatal => 1, emerg => 1, 200 fatal => 1, emerg => 1, exit => 1,
140 alert => 2, 201 alert => 2,
141 critical => 3, crit => 3, 202 critical => 3, crit => 3,
142 error => 4, err => 4, 203 error => 4, err => 4, die => 4,
143 warn => 5, warning => 5, 204 warn => 5, warning => 5,
144 note => 6, notice => 6, 205 note => 6, notice => 6,
145 info => 7, 206 info => 7,
146 debug => 8, 207 debug => 8,
147 trace => 9, 208 trace => 9,
148); 209);
149 210
150sub now () { time } 211sub now () { time }
212
151AnyEvent::post_detect { 213AnyEvent::post_detect {
152 *now = \&AE::now; 214 *now = \&AE::now;
153}; 215};
154 216
155our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace); 217our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
156 218
157# time, ctx, level, msg 219# time, ctx, level, msg
158sub _format($$$$) { 220sub _format($$$$) {
159 my $pfx = ft $_[0]; 221 my $ts = ft $_[0];
222 my $ct = " ";
160 223
161 join "", 224 my @res;
162 map "$pfx $_\n", 225
163 split /\n/,
164 sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3] 226 for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
227 push @res, "$ts$ct$_\n";
228 $ct = " + ";
229 }
230
231 join "", @res
165} 232}
166 233
167sub _log { 234sub _log {
168 my ($ctx, $level, $format, @args) = @_; 235 my ($ctx, $level, $format, @args) = @_;
169 236
237 $level = $level > 0 && $level <= 9
238 ? $level+0
170 $level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 239 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
171 240
172 my $mask = 1 << $level; 241 my $mask = 1 << $level;
173 my $now = AE::now;
174 242
175 my (@ctx, $did_format, $fmt); 243 my ($success, %seen, @ctx, $now, $fmt);
176 244
177 do { 245 do
178 if ($ctx->[1] & $mask) { 246 {
247 # skip if masked
248 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
249 if ($ctx->[3]) {
179 # logging target found 250 # logging target found
180 251
181 # get raw message 252 # now get raw message, unless we have it already
182 unless ($did_format) { 253 unless ($now) {
183 $format = $format->() if ref $format; 254 $format = $format->() if ref $format;
184 $format = sprintf $format, @args if @args; 255 $format = sprintf $format, @args if @args;
185 $format =~ s/\n$//; 256 $format =~ s/\n$//;
186 $did_format = 1; 257 $now = now;
258 };
259
260 # format msg
261 my $str = $ctx->[4]
262 ? $ctx->[4]($now, $_[0], $level, $format)
263 : ($fmt ||= _format $now, $_[0], $level, $format);
264
265 $success = 1;
266
267 $ctx->[3]($str)
268 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
269 } else {
270 push @ctx, values %{ $ctx->[2] }; # not masked - propagate
271 }
187 }; 272 }
188
189 # format msg
190 my $str = $ctx->[4]
191 ? $ctx->[4]($now, $_[0], $level, $format)
192 : $fmt ||= _format $now, $_[0], $level, $format;
193
194 $ctx->[3]($str)
195 and next;
196 } 273 }
197
198 # not consume - push parent contexts
199 push @ctx, values %{ $ctx->[2] };
200 } while $ctx = pop @ctx; 274 while $ctx = pop @ctx;
201 275
202 exit 1 if $level <= 1; 276 exit 1 if $level <= 1;
277
278 $success
203} 279}
204 280
205sub log($$;@) { 281sub log($$;@) {
206 _log 282 _log
207 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 283 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
211*AnyEvent::log = *AE::log = \&log; 287*AnyEvent::log = *AE::log = \&log;
212 288
213=item $logger = AnyEvent::Log::logger $level[, \$enabled] 289=item $logger = AnyEvent::Log::logger $level[, \$enabled]
214 290
215Creates a code reference that, when called, acts as if the 291Creates a code reference that, when called, acts as if the
216C<AnyEvent::Log::log> function was called at this point with the givne 292C<AnyEvent::Log::log> function was called at this point with the given
217level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with 293level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
218the C<AnyEvent::Log::log> function: 294the C<AnyEvent::Log::log> function:
219 295
220 my $debug_log = AnyEvent::Log::logger "debug"; 296 my $debug_log = AnyEvent::Log::logger "debug";
221 297
246 # and later in your program 322 # and later in your program
247 $debug_log->("yo, stuff here") if $debug; 323 $debug_log->("yo, stuff here") if $debug;
248 324
249 $debug and $debug_log->("123"); 325 $debug and $debug_log->("123");
250 326
251Note: currently the enabled var is always true - that will be fixed in a
252future version :)
253
254=cut 327=cut
255 328
256our %LOGGER; 329our %LOGGER;
257 330
258# re-assess logging status for all loggers 331# re-assess logging status for all loggers
259sub _reassess { 332sub _reassess {
333 local $SIG{__DIE__};
334 my $die = sub { die };
335
260 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) { 336 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
261 my ($ctx, $level, $renabled) = @$_; 337 my ($ctx, $level, $renabled) = @$_;
262 338
263 # to detetc whether a message would be logged, we # actually 339 # to detect whether a message would be logged, we actually
264 # try to log one and die. this isn't # fast, but we can be 340 # try to log one and die. this isn't fast, but we can be
265 # sure that the logging decision is correct :) 341 # sure that the logging decision is correct :)
266 342
267 $$renabled = !eval { 343 $$renabled = !eval {
268 local $SIG{__DIE__};
269
270 _log $ctx, $level, sub { die }; 344 _log $ctx, $level, $die;
271 345
272 1 346 1
273 }; 347 };
274
275 $$renabled = 1; # TODO
276 } 348 }
277} 349}
278 350
279sub _logger($;$) { 351sub _logger {
280 my ($ctx, $level, $renabled) = @_; 352 my ($ctx, $level, $renabled) = @_;
281 353
282 $renabled ||= \my $enabled;
283
284 $$renabled = 1; 354 $$renabled = 1;
285 355
286 my $logger = [$ctx, $level, $renabled]; 356 my $logger = [$ctx, $level, $renabled];
287 357
288 $LOGGER{$logger+0} = $logger; 358 $LOGGER{$logger+0} = $logger;
289 359
290 _reassess $logger+0; 360 _reassess $logger+0;
291 361
362 require AnyEvent::Util;
292 my $guard = AnyEvent::Util::guard { 363 my $guard = AnyEvent::Util::guard (sub {
293 # "clean up" 364 # "clean up"
294 delete $LOGGER{$logger+0}; 365 delete $LOGGER{$logger+0};
295 }; 366 });
296 367
297 sub { 368 sub {
298 $guard if 0; # keep guard alive, but don't cause runtime overhead 369 $guard if 0; # keep guard alive, but don't cause runtime overhead
299 370
300 _log $ctx, $level, @_ 371 _log $ctx, $level, @_
306 _logger 377 _logger
307 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 378 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
308 @_ 379 @_
309} 380}
310 381
311#TODO
312
313=back 382=back
314 383
315=head1 LOGGING CONTEXTS 384=head1 LOGGING CONTEXTS
316 385
317This module associates every log message with a so-called I<logging 386This module associates every log message with a so-called I<logging
318context>, based on the package of the caller. Every perl package has its 387context>, based on the package of the caller. Every perl package has its
319own logging context. 388own logging context.
320 389
321A logging context has two major responsibilities: logging the message and 390A logging context has three major responsibilities: filtering, logging and
322propagating the message to other contexts. 391propagating the message.
323 392
324For logging, the context stores a set of logging levels that it 393For the first purpose, filtering, each context has a set of logging
325potentially wishes to log, a formatting callback that takes the timestamp, 394levels, called the log level mask. Messages not in the set will be ignored
395by this context (masked).
396
397For logging, the context stores a formatting callback (which takes the
326context, level and string emssage and formats it in the way it should be 398timestamp, context, level and string message and formats it in the way
327logged, and a logging callback, which is responsible for actually logging 399it should be logged) and a logging callback (which is responsible for
328the formatted message and telling C<AnyEvent::Log> whether it has consumed 400actually logging the formatted message and telling C<AnyEvent::Log>
329the message, or whether it should be propagated. 401whether it has consumed the message, or whether it should be propagated).
330 402
331For propagation, a context can have any number of attached I<parent 403For propagation, a context can have any number of attached I<slave
332contexts>. They will be ignored if the logging callback consumes the 404contexts>. Any message that is neither masked by the logging mask nor
333message, but in all other cases, the log message will be passed to all 405masked by the logging callback returning true will be passed to all slave
334parent contexts attached to a context. 406contexts.
407
408Each call to a logging function will log the message at most once per
409context, so it does not matter (much) if there are cycles or if the
410message can arrive at the same context via multiple paths.
335 411
336=head2 DEFAULTS 412=head2 DEFAULTS
337 413
338By default, all logging contexts have an empty set of log levels, a 414By default, all logging contexts have an full set of log levels ("all"), a
339disabled logging callback and the default formatting callback. 415disabled logging callback and the default formatting callback.
340 416
341Package contexts have the package name as logging title by default. 417Package contexts have the package name as logging title by default.
342 418
343They have exactly one parent - the context of the "parent" package. The 419They have exactly one slave - the context of the "parent" package. The
344parent package is simply defined to be the package name without the last 420parent package is simply defined to be the package name without the last
345component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>, 421component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
346and C<AnyEvent> becomes the empty string. 422and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
423exception of the rule - just like the "parent" of any single-component
424package name in Perl is C<main>, the default slave of any top-level
425package context is C<$AnyEvent::Log::COLLECT>.
347 426
348Since perl packages form only an approximate hierarchy, this parent 427Since perl packages form only an approximate hierarchy, this slave
349context can of course be removed. 428context can of course be removed.
350 429
351All other (anonymous) contexts have no parents and an empty title by 430All other (anonymous) contexts have no slaves and an empty title by
352default. 431default.
353 432
354When the module is first loaded, it configures the root context (the one 433When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
355with the empty string) to simply dump all log messages to C<STDERR>, 434context that simply logs everything via C<warn>, without propagating
356and sets it's log level set to all levels up to the one specified by 435anything anywhere by default. The purpose of this context is to provide
357C<$ENV{PERL_ANYEVENT_VERBOSE}>. 436a convenient place to override the global logging target or to attach
437additional log targets. It's not meant for filtering.
358 438
439It then creates the C<$AnyEvent::Log::FILTER> context whose
440purpose is to suppress all messages with priority higher
441than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
442C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
443is to simply provide filtering according to some global log level.
444
445Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
446and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
447leaves it at default config. Its purpose is simply to collect all log
448messages system-wide.
449
450The hierarchy is then:
451
452 any package, eventually -> $COLLECT -> $FILTER -> $LOG
453
359The effetc of all this is that log messages, by default, wander up to the 454The effect of all this is that log messages, by default, wander up to the
360root context and will be logged to STDERR if their log level is less than 455C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
361or equal to C<$ENV{PERL_ANYEVENT_VERBOSE}>. 456from there to C<$AnyEvent::Log::FILTER> where log messages with lower
457priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
458to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
362 459
460This makes it easy to set a global logging level (by modifying $FILTER),
461but still allow other contexts to send, for example, their debug and trace
462messages to the $LOG target despite the global logging level, or to attach
463additional log targets that log messages, regardless of the global logging
464level.
465
466It also makes it easy to modify the default warn-logger ($LOG) to
467something that logs to a file, or to attach additional logging targets
468(such as loggign to a file) by attaching it to $FILTER.
469
363=head2 CREATING/FINDING A CONTEXT 470=head2 CREATING/FINDING/DESTROYING CONTEXTS
364 471
365=over 4 472=over 4
366 473
367=item $ctx = AnyEvent::Log::ctx [$pkg] 474=item $ctx = AnyEvent::Log::ctx [$pkg]
368 475
383 490
384 ref $pkg 491 ref $pkg
385 ? $pkg 492 ? $pkg
386 : defined $pkg 493 : defined $pkg
387 ? $CTX{$pkg} ||= AnyEvent::Log::_pkg_ctx $pkg 494 ? $CTX{$pkg} ||= AnyEvent::Log::_pkg_ctx $pkg
388 : bless [undef, 0, undef, $default_log_cb], "AnyEvent::Log::Ctx" 495 : bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
389} 496}
390 497
391# create default root context 498=item AnyEvent::Log::reset
392{ 499
393 my $root = ctx undef; 500Resets all package contexts and recreates the default hierarchy if
394 $root->[0] = ""; 501necessary, i.e. resets the logging subsystem to defaults, as much as
395 $root->title ("default"); 502possible. This process keeps references to contexts held by other parts of
396 $root->level ($AnyEvent::VERBOSE); undef $AnyEvent::VERBOSE; 503the program intact.
397 $root->log_cb (sub { 504
398 print STDERR shift; 505This can be used to implement config-file (re-)loading: before loading a
399 0 506configuration, reset all contexts.
507
508=cut
509
510sub reset {
511 # hard to kill complex data structures
512 # we "recreate" all package loggers and reset the hierarchy
513 while (my ($k, $v) = each %CTX) {
514 @$v = ($k, (1 << 10) - 1 - 1, { });
515
516 $v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
400 }); 517 }
401 $CTX{""} = $root; 518
519 @$_ = ($_->[0], (1 << 10) - 1 - 1)
520 for $LOG, $FILTER, $COLLECT;
521
522 #$LOG->slaves;
523 $LOG->title ('$AnyEvent::Log::LOG');
524 $LOG->log_to_warn;
525
526 $FILTER->slaves ($LOG);
527 $FILTER->title ('$AnyEvent::Log::FILTER');
528 $FILTER->level ($AnyEvent::VERBOSE);
529
530 $COLLECT->slaves ($FILTER);
531 $COLLECT->title ('$AnyEvent::Log::COLLECT');
532
533 _reassess;
402} 534}
535
536# create the default logger contexts
537$LOG = ctx undef;
538$FILTER = ctx undef;
539$COLLECT = ctx undef;
540
541AnyEvent::Log::reset;
542
543# hello, CPAN, please catch me
544package AnyEvent::Log::LOG;
545package AE::Log::LOG;
546package AnyEvent::Log::FILTER;
547package AE::Log::FILTER;
548package AnyEvent::Log::COLLECT;
549package AE::Log::COLLECT;
550
551package AnyEvent::Log::Ctx;
552
553# 0 1 2 3 4
554# [$title, $level, %$slaves, &$logcb, &$fmtcb]
555
556=item $ctx = new AnyEvent::Log::Ctx methodname => param...
557
558This is a convenience constructor that makes it simpler to construct
559anonymous logging contexts.
560
561Each key-value pair results in an invocation of the method of the same
562name as the key with the value as parameter, unless the value is an
563arrayref, in which case it calls the method with the contents of the
564array. The methods are called in the same order as specified.
565
566Example: create a new logging context and set both the default logging
567level, some slave contexts and a logging callback.
568
569 $ctx = new AnyEvent::Log::Ctx
570 title => "dubious messages",
571 level => "error",
572 log_cb => sub { print STDOUT shift; 0 },
573 slaves => [$ctx1, $ctx, $ctx2],
574 ;
403 575
404=back 576=back
405 577
406=cut 578=cut
407 579
408package AnyEvent::Log::Ctx; 580sub new {
581 my $class = shift;
409 582
410# 0 1 2 3 4 583 my $ctx = AnyEvent::Log::ctx undef;
411# [$title, $level, %$parents, &$logcb, &$fmtcb] 584
585 while (@_) {
586 my ($k, $v) = splice @_, 0, 2;
587 $ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
588 }
589
590 bless $ctx, $class # do we really support subclassing, hmm?
591}
592
412 593
413=head2 CONFIGURING A LOG CONTEXT 594=head2 CONFIGURING A LOG CONTEXT
414 595
415The following methods can be used to configure the logging context. 596The following methods can be used to configure the logging context.
416 597
432 613
433=back 614=back
434 615
435=head3 LOGGING LEVELS 616=head3 LOGGING LEVELS
436 617
437The following methods deal with the logging level set associated wiht the log context. 618The following methods deal with the logging level set associated with the
619log context.
438 620
439The most common method to use is probably C<< $ctx->level ($level) >>, 621The most common method to use is probably C<< $ctx->level ($level) >>,
440which configures the specified and any higher priority levels. 622which configures the specified and any higher priority levels.
441 623
624All functions which accept a list of levels also accept the special string
625C<all> which expands to all logging levels.
626
442=over 4 627=over 4
443 628
444=item $ctx->levels ($level[, $level...) 629=item $ctx->levels ($level[, $level...)
445 630
446Enables logging fot the given levels and disables it for all others. 631Enables logging for the given levels and disables it for all others.
447 632
448=item $ctx->level ($level) 633=item $ctx->level ($level)
449 634
450Enables logging for the given level and all lower level (higher priority) 635Enables logging for the given level and all lower level (higher priority)
451ones. Specifying a level of C<0> or C<off> disables all logging for this 636ones. In addition to normal logging levels, specifying a level of C<0> or
452level. 637C<off> disables all logging for this level.
453 638
454Example: log warnings, errors and higher priority messages. 639Example: log warnings, errors and higher priority messages.
455 640
456 $ctx->level ("warn"); 641 $ctx->level ("warn");
457 $ctx->level (5); # same thing, just numeric 642 $ctx->level (5); # same thing, just numeric
465Disables logging for the given levels, leaving all others unchanged. 650Disables logging for the given levels, leaving all others unchanged.
466 651
467=cut 652=cut
468 653
469sub _lvl_lst { 654sub _lvl_lst {
655 map {
656 $_ > 0 && $_ <= 9 ? $_+0
657 : $_ eq "all" ? (1 .. 9)
470 map { $_ > 0 && $_ <= 9 ? $_+0 : $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught" } 658 : $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught"
471 @_ 659 } @_
472} 660}
473 661
474our $NOP_CB = sub { 0 }; 662our $NOP_CB = sub { 0 };
475 663
476sub levels { 664sub levels {
481 AnyEvent::Log::_reassess; 669 AnyEvent::Log::_reassess;
482} 670}
483 671
484sub level { 672sub level {
485 my $ctx = shift; 673 my $ctx = shift;
486 my $lvl = $_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[0]; 674 my $lvl = $_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
675
487 $ctx->[1] = ((1 << $lvl) - 1) << 1; 676 $ctx->[1] = ((1 << $lvl) - 1) << 1;
488 AnyEvent::Log::_reassess; 677 AnyEvent::Log::_reassess;
489} 678}
490 679
491sub enable { 680sub enable {
502 AnyEvent::Log::_reassess; 691 AnyEvent::Log::_reassess;
503} 692}
504 693
505=back 694=back
506 695
507=head3 PARENT CONTEXTS 696=head3 SLAVE CONTEXTS
508 697
509The following methods attach and detach another logging context to a 698The following methods attach and detach another logging context to a
510logging context. 699logging context.
511 700
512Log messages are propagated to all parent contexts, unless the logging 701Log messages are propagated to all slave contexts, unless the logging
513callback consumes the message. 702callback consumes the message.
514 703
515=over 4 704=over 4
516 705
517=item $ctx->attach ($ctx2[, $ctx3...]) 706=item $ctx->attach ($ctx2[, $ctx3...])
518 707
519Attaches the given contexts as parents to this context. It is not an error 708Attaches the given contexts as slaves to this context. It is not an error
520to add a context twice (the second add will be ignored). 709to add a context twice (the second add will be ignored).
521 710
522A context can be specified either as package name or as a context object. 711A context can be specified either as package name or as a context object.
523 712
524=item $ctx->detach ($ctx2[, $ctx3...]) 713=item $ctx->detach ($ctx2[, $ctx3...])
525 714
526Removes the given parents from this context - it's not an error to attempt 715Removes the given slaves from this context - it's not an error to attempt
527to remove a context that hasn't been added. 716to remove a context that hasn't been added.
528 717
529A context can be specified either as package name or as a context object. 718A context can be specified either as package name or as a context object.
719
720=item $ctx->slaves ($ctx2[, $ctx3...])
721
722Replaces all slaves attached to this context by the ones given.
530 723
531=cut 724=cut
532 725
533sub attach { 726sub attach {
534 my $ctx = shift; 727 my $ctx = shift;
542 735
543 delete $ctx->[2]{$_+0} 736 delete $ctx->[2]{$_+0}
544 for map { AnyEvent::Log::ctx $_ } @_; 737 for map { AnyEvent::Log::ctx $_ } @_;
545} 738}
546 739
740sub slaves {
741 undef $_[0][2];
742 &attach;
743}
744
547=back 745=back
548 746
549=head3 MESSAGE LOGGING 747=head3 LOG TARGETS
550 748
551The following methods configure how the logging context actually does 749The following methods configure how the logging context actually does
552the logging (which consists of foratting the message and printing it or 750the logging (which consists of formatting the message and printing it or
553whatever it wants to do with it) and also allows you to log messages 751whatever it wants to do with it).
554directly to a context, without going via your package context.
555 752
556=over 4 753=over 4
557 754
558=item $ctx->log_cb ($cb->($str)) 755=item $ctx->log_cb ($cb->($str)
559 756
560Replaces the logging callback on the context (C<undef> disables the 757Replaces the logging callback on the context (C<undef> disables the
561logging callback). 758logging callback).
562 759
563The logging callback is responsible for handling formatted log messages 760The logging callback is responsible for handling formatted log messages
564(see C<fmt_cb> below) - normally simple text strings that end with a 761(see C<fmt_cb> below) - normally simple text strings that end with a
565newline (and are possibly multiline themselves). 762newline (and are possibly multiline themselves).
566 763
567It also has to return true iff it has consumed the log message, and false 764It also has to return true iff it has consumed the log message, and false
568if it hasn't. Consuming a message means that it will not be sent to any 765if it hasn't. Consuming a message means that it will not be sent to any
569parent context. When in doubt, return C<0> from your logging callback. 766slave context. When in doubt, return C<0> from your logging callback.
570 767
571Example: a very simple logging callback, simply dump the message to STDOUT 768Example: a very simple logging callback, simply dump the message to STDOUT
572and do not consume it. 769and do not consume it.
573 770
574 $ctx->log_cb (sub { print STDERR shift; 0 }); 771 $ctx->log_cb (sub { print STDERR shift; 0 });
575 772
773You can filter messages by having a log callback that simply returns C<1>
774and does not do anything with the message, but this counts as "message
775being logged" and might not be very efficient.
776
777Example: propagate all messages except for log levels "debug" and
778"trace". The messages will still be generated, though, which can slow down
779your program.
780
781 $ctx->levels ("debug", "trace");
782 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
783
576=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message)) 784=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
577 785
578Replaces the fornatting callback on the cobntext (C<undef> restores the 786Replaces the formatting callback on the context (C<undef> restores the
579default formatter). 787default formatter).
580 788
581The callback is passed the (possibly fractional) timestamp, the original 789The callback is passed the (possibly fractional) timestamp, the original
582logging context, the (numeric) logging level and the raw message string and needs to 790logging context, the (numeric) logging level and the raw message string
583return a formatted log message. In most cases this will be a string, but 791and needs to return a formatted log message. In most cases this will be a
584it could just as well be an array reference that just stores the values. 792string, but it could just as well be an array reference that just stores
793the values.
794
795If, for some reason, you want to use C<caller> to find out more baout the
796logger then you should walk up the call stack until you are no longer
797inside the C<AnyEvent::Log> package.
585 798
586Example: format just the raw message, with numeric log level in angle 799Example: format just the raw message, with numeric log level in angle
587brackets. 800brackets.
588 801
589 $ctx->fmt_cb (sub { 802 $ctx->fmt_cb (sub {
606 "$msg->[3]"; 819 "$msg->[3]";
607 820
608 0 821 0
609 }); 822 });
610 823
824=item $ctx->log_to_warn
825
826Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
827(usually this logs to STDERR).
828
829=item $ctx->log_to_file ($path)
830
831Sets the C<log_cb> to log to a file (by appending), unbuffered.
832
833=item $ctx->log_to_path ($path)
834
835Same as C<< ->log_to_file >>, but opens the file for each message. This
836is much slower, but allows you to change/move/rename/delete the file at
837basically any time.
838
839Needless(?) to say, if you do not want to be bitten by some evil person
840calling C<chdir>, the path should be absolute. Doesn't help with
841C<chroot>, but hey...
842
843=item $ctx->log_to_syslog ([$log_flags])
844
845Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
846the others in the obvious way. If specified, then the C<$log_flags> are
847simply or'ed onto the priority argument and can contain any C<LOG_xxx>
848flags valid for Sys::Syslog::syslog, except for the priority levels.
849
850Note that this function also sets a C<fmt_cb> - the logging part requires
851an array reference with [$level, $str] as input.
852
611=cut 853=cut
612 854
613sub log_cb { 855sub log_cb {
614 my ($ctx, $cb) = @_; 856 my ($ctx, $cb) = @_;
615 857
616 $ctx->[3] = $cb || $default_log_cb; 858 $ctx->[3] = $cb;
617} 859}
618 860
619sub fmt_cb { 861sub fmt_cb {
620 my ($ctx, $cb) = @_; 862 my ($ctx, $cb) = @_;
621 863
622 $ctx->[4] = $cb; 864 $ctx->[4] = $cb;
623} 865}
624 866
867sub log_to_warn {
868 my ($ctx, $path) = @_;
869
870 $ctx->log_cb (sub {
871 warn shift;
872 0
873 });
874}
875
876sub log_to_file {
877 my ($ctx, $path) = @_;
878
879 open my $fh, ">>", $path
880 or die "$path: $!";
881
882 $ctx->log_cb (sub {
883 syswrite $fh, shift;
884 0
885 });
886}
887
888sub log_to_path {
889 my ($ctx, $path) = @_;
890
891 $ctx->log_cb (sub {
892 open my $fh, ">>", $path
893 or die "$path: $!";
894
895 syswrite $fh, shift;
896 0
897 });
898}
899
900sub log_to_syslog {
901 my ($ctx, $flags) = @_;
902
903 require Sys::Syslog;
904
905 $ctx->fmt_cb (sub {
906 my $str = $_[3];
907 $str =~ s/\n(?=.)/\n+ /g;
908
909 [$_[2], "($_[1][0]) $str"]
910 });
911
912 $ctx->log_cb (sub {
913 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
914
915 Sys::Syslog::syslog ($flags | ($lvl - 1), $_)
916 for split /\n/, $_[0][1];
917
918 0
919 });
920}
921
922=back
923
924=head3 MESSAGE LOGGING
925
926These methods allow you to log messages directly to a context, without
927going via your package context.
928
929=over 4
930
625=item $ctx->log ($level, $msg[, @params]) 931=item $ctx->log ($level, $msg[, @params])
626 932
627Same as C<AnyEvent::Log::log>, but uses the given context as log context. 933Same as C<AnyEvent::Log::log>, but uses the given context as log context.
628 934
629=item $logger = $ctx->logger ($level[, \$enabled]) 935=item $logger = $ctx->logger ($level[, \$enabled])
634=cut 940=cut
635 941
636*log = \&AnyEvent::Log::_log; 942*log = \&AnyEvent::Log::_log;
637*logger = \&AnyEvent::Log::_logger; 943*logger = \&AnyEvent::Log::_logger;
638 944
945=back
946
947=cut
948
949package AnyEvent::Log;
950
951=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
952
953Logging can also be configured by setting the environment variable
954C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
955
956The value consists of one or more logging context specifications separated
957by C<:> or whitespace. Each logging specification in turn starts with a
958context name, followed by C<=>, followed by zero or more comma-separated
959configuration directives, here are some examples:
960
961 # set default logging level
962 filter=warn
963
964 # log to file instead of to stderr
965 log=file=/tmp/mylog
966
967 # log to file in addition to stderr
968 log=+%file:%file=file=/tmp/mylog
969
970 # enable debug log messages, log warnings and above to syslog
971 filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
972
973 # log trace messages (only) from AnyEvent::Debug to file
974 AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
975
976A context name in the log specification can be any of the following:
977
978=over 4
979
980=item C<collect>, C<filter>, C<log>
981
982Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
983C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
984
985=item C<%name>
986
987Context names starting with a C<%> are anonymous contexts created when the
988name is first mentioned. The difference to package contexts is that by
989default they have no attached slaves.
990
991=item a perl package name
992
993Any other string references the logging context associated with the given
994Perl C<package>. In the unlikely case where you want to specify a package
995context that matches on of the other context name forms, you can add a
996C<::> to the package name to force interpretation as a package.
997
998=back
999
1000The configuration specifications can be any number of the following:
1001
1002=over 4
1003
1004=item C<stderr>
1005
1006Configures the context to use Perl's C<warn> function (which typically
1007logs to C<STDERR>). Works like C<log_to_warn>.
1008
1009=item C<file=>I<path>
1010
1011Configures the context to log to a file with the given path. Works like
1012C<log_to_file>.
1013
1014=item C<path=>I<path>
1015
1016Configures the context to log to a file with the given path. Works like
1017C<log_to_path>.
1018
1019=item C<syslog> or C<syslog=>I<expr>
1020
1021Configures the context to log to syslog. If I<expr> is given, then it is
1022evaluated in the L<Sys::Syslog> package, so you could use:
1023
1024 log=syslog=LOG_LOCAL0
1025
1026=item C<nolog>
1027
1028Configures the context to not log anything by itself, which is the
1029default. Same as C<< $ctx->log_cb (undef) >>.
1030
1031=item C<0> or C<off>
1032
1033Sets the logging level of the context ot C<0>, i.e. all messages will be
1034filtered out.
1035
1036=item C<all>
1037
1038Enables all logging levels, i.e. filtering will effectively be switched
1039off (the default).
1040
1041=item C<only>
1042
1043Disables all logging levels, and changes the interpretation of following
1044level specifications to enable the specified level only.
1045
1046Example: only enable debug messages for a context.
1047
1048 context=only,debug
1049
1050=item C<except>
1051
1052Enables all logging levels, and changes the interpretation of following
1053level specifications to disable that level. Rarely used.
1054
1055Example: enable all logging levels except fatal and trace (this is rather
1056nonsensical).
1057
1058 filter=exept,fatal,trace
1059
1060=item C<level>
1061
1062Enables all logging levels, and changes the interpretation of following
1063level specifications to be "that level or any higher priority
1064message". This is the default.
1065
1066Example: log anything at or above warn level.
1067
1068 filter=warn
1069
1070 # or, more verbose
1071 filter=only,level,warn
1072
1073=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
1074
1075A numeric loglevel or the name of a loglevel will be interpreted according
1076to the most recent C<only>, C<except> or C<level> directive. By default,
1077specifying a logging level enables that and any higher priority messages.
1078
1079=item C<+>I<context>
1080
1081Attaches the named context as slave to the context.
1082
1083=item C<+>
1084
1085A line C<+> detaches all contexts, i.e. clears the slave list from the
1086context. Anonymous (C<%name>) contexts have no attached slaves by default,
1087but package contexts have the parent context as slave by default.
1088
1089Example: log messages from My::Module to a file, do not send them to the
1090default log collector.
1091
1092 My::Module=+,file=/tmp/mymodulelog
1093
1094=back
1095
1096Any character can be escaped by prefixing it with a C<\> (backslash), as
1097usual, so to log to a file containing a comma, colon, backslash and some
1098spaces in the filename, you would do this:
1099
1100 PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
1101
1102Since whitespace (which includes newlines) is allowed, it is fine to
1103specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
1104
1105 PERL_ANYEVENT_LOG="
1106 filter=warn
1107 AnyEvent::Debug=+%trace
1108 %trace=only,trace,+log
1109 " myprog
1110
1111Also, in the unlikely case when you want to concatenate specifications,
1112use whitespace as separator, as C<::> will be interpreted as part of a
1113module name, an empty spec with two separators:
1114
1115 PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
1116
1117=cut
1118
1119for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
1120 my %anon;
1121
1122 my $pkg = sub {
1123 $_[0] eq "log" ? $LOG
1124 : $_[0] eq "filter" ? $FILTER
1125 : $_[0] eq "collect" ? $COLLECT
1126 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef)
1127 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1128 : die # never reached?
1129 };
1130
1131 /\G[[:space:]]+/gc; # skip initial whitespace
1132
1133 while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
1134 my $ctx = $pkg->($1);
1135 my $level = "level";
1136
1137 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1138 for ("$1") {
1139 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1140 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1141 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1142 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
1143 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1144 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1145 } elsif ($_ eq "+" ) { $ctx->slaves;
1146 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1147 } elsif ($_ eq "all" ) { $ctx->level ("all");
1148 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1149 } elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
1150 } elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
1151 } elsif (/^\d$/ ) { $ctx->$level ($_);
1152 } elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
1153 } else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
1154 }
1155 }
1156
1157 /\G,/gc or last;
1158 }
1159
1160 /\G[:[:space:]]+/gc or last;
1161 }
1162
1163 /\G[[:space:]]+/gc; # skip trailing whitespace
1164
1165 if (/\G(.+)/g) {
1166 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1167 }
1168}
1169
6391; 11701;
1171
1172=head1 EXAMPLES
1173
1174This section shows some common configurations, both as code, and as
1175C<PERL_ANYEVENT_LOG> string.
1176
1177=over 4
1178
1179=item Setting the global logging level.
1180
1181Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
1182running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
1183the root context at runtime:
1184
1185 PERL_ANYEVENT_VERBOSE=5 ./myprog
1186
1187 PERL_ANYEVENT_LOG=log=warn
1188
1189 $AnyEvent::Log::FILTER->level ("warn");
1190
1191=item Append all messages to a file instead of sending them to STDERR.
1192
1193This is affected by the global logging level.
1194
1195 $AnyEvent::Log::LOG->log_to_file ($path);
1196
1197 PERL_ANYEVENT_LOG=log=file=/some/path
1198
1199=item Write all messages with priority C<error> and higher to a file.
1200
1201This writes them only when the global logging level allows it, because
1202it is attached to the default context which is invoked I<after> global
1203filtering.
1204
1205 $AnyEvent::Log::FILTER->attach
1206 new AnyEvent::Log::Ctx log_to_file => $path);
1207
1208 PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
1209
1210This writes them regardless of the global logging level, because it is
1211attached to the toplevel context, which receives all messages I<before>
1212the global filtering.
1213
1214 $AnyEvent::Log::COLLECT->attach (
1215 new AnyEvent::Log::Ctx log_to_file => $path);
1216
1217 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1218
1219In both cases, messages are still written to STDERR.
1220
1221=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
1222
1223Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
1224context - this simply circumvents the global filtering for trace messages.
1225
1226 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
1227 $debug->attach ($AnyEvent::Log::LOG);
1228
1229 PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
1230
1231This of course works for any package, not just L<AnyEvent::Debug>, but
1232assumes the log level for AnyEvent::Debug hasn't been changed from the
1233default.
640 1234
641=back 1235=back
642 1236
643=head1 AUTHOR 1237=head1 AUTHOR
644 1238
645 Marc Lehmann <schmorp@schmorp.de> 1239 Marc Lehmann <schmorp@schmorp.de>
646 http://home.schmorp.de/ 1240 http://home.schmorp.de/
647 1241
648=cut 1242=cut
1243

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