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Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs.
Revision 1.30 by root, Thu Aug 25 00:24:47 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, 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
51before starting your program, or change the logging level at runtime wiht 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 amount of documentation might indicate otherwise, but the module is
62still just below 300 lines of code.
63
64=head1 LOGGING LEVELS
65
66Logging levels in this module range from C<1> (highest priority) to C<9>
67(lowest priority). Note that the lowest numerical value is the highest
68priority, so when this document says "higher priority" it means "lower
69numerical value".
70
71Instead of specifying levels by name you can also specify them by aliases:
72
73 LVL NAME SYSLOG PERL NOTE
74 1 fatal emerg exit aborts program!
75 2 alert
76 3 critical crit
77 4 error err die
78 5 warn warning
79 6 note notice
80 7 info
81 8 debug
82 9 trace
83
84As you can see, some logging levels have multiple aliases - the first one
85is the "official" name, the second one the "syslog" name (if it differs)
86and the third one the "perl" name, suggesting that you log C<die> messages
87at C<error> priority.
88
89You can normally only log a single message at highest priority level
90(C<1>, C<fatal>), because logging a fatal message will also quit the
91program - so use it sparingly :)
92
93Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
94or C<all> - these are only valid in the methods they are documented for.
95
62=head1 LOGGING FUNCTIONS 96=head1 LOGGING FUNCTIONS
63 97
64These functions allow you to log messages. They always use the caller's 98These functions allow you to log messages. They always use the caller's
65package as a "logging module/source". Also, the main logging function is 99package as a "logging context". Also, the main logging function C<log> is
66callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is 100callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
67loaded. 101loaded.
68 102
69=over 4 103=over 4
70 104
75use Carp (); 109use Carp ();
76use POSIX (); 110use POSIX ();
77 111
78use AnyEvent (); BEGIN { AnyEvent::common_sense } 112use AnyEvent (); BEGIN { AnyEvent::common_sense }
79use AnyEvent::Util (); 113use AnyEvent::Util ();
114
115our $VERSION = $AnyEvent::VERSION;
116
117our ($COLLECT, $FILTER, $LOG);
80 118
81our ($now_int, $now_str1, $now_str2); 119our ($now_int, $now_str1, $now_str2);
82 120
83# Format Time, not public - yet? 121# Format Time, not public - yet?
84sub ft($) { 122sub ft($) {
89 if $now_int != $i; 127 if $now_int != $i;
90 128
91 "$now_str1$f$now_str2" 129 "$now_str1$f$now_str2"
92} 130}
93 131
94our %CTX; # all logging contexts 132our %CTX; # all package contexts
95 133
96# creates a default package context object for the given package 134# creates a default package context object for the given package
97sub _pkg_ctx($) { 135sub _pkg_ctx($) {
98 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx"; 136 my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
99 137
100 # link "parent" package 138 # link "parent" package
101 my $pkg = $_[0] =~ /^(.+)::/ ? $1 : ""; 139 my $parent = $_[0] =~ /^(.+)::/
140 ? $CTX{$1} ||= &_pkg_ctx ("$1")
141 : $COLLECT;
102 142
103 $pkg = $CTX{$pkg} ||= &_pkg_ctx ($pkg);
104 $ctx->[2]{$pkg+0} = $pkg; 143 $ctx->[2]{$parent+0} = $parent;
105 144
106 $ctx 145 $ctx
107} 146}
108 147
109=item AnyEvent::Log::log $level, $msg[, @args] 148=item AnyEvent::Log::log $level, $msg[, @args]
110 149
111Requests logging of the given C<$msg> with the given log level (1..9). 150Requests logging of the given C<$msg> with the given log level, and
112You can also use the following strings as log level: C<fatal> (1), 151returns true if the message was logged I<somewhere>.
113C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114C<info> (7), C<debug> (8), C<trace> (9).
115 152
116For C<fatal> log levels, the program will abort. 153For C<fatal> log levels, the program will abort.
117 154
118If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the 155If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
119C<$msg> is interpreted as an sprintf format string. 156C<$msg> is interpreted as an sprintf format string.
125supposed to return the message. It will be called only then the message 162supposed to return the message. It will be called only then the message
126actually gets logged, which is useful if it is costly to create the 163actually gets logged, which is useful if it is costly to create the
127message in the first place. 164message in the first place.
128 165
129Whether the given message will be logged depends on the maximum log level 166Whether the given message will be logged depends on the maximum log level
130and the caller's package. 167and the caller's package. The return value can be used to ensure that
168messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
169runtime error it tries to log it at C<die> level, but if that message is
170lost it simply uses warn.
131 171
132Note that you can (and should) call this function as C<AnyEvent::log> or 172Note that you can (and should) call this function as C<AnyEvent::log> or
133C<AE::log>, without C<use>-ing this module if possible (i.e. you don't 173C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
134need any additional functionality), as those functions will load the 174need any additional functionality), as those functions will load the
135logging module on demand only. They are also much shorter to write. 175logging module on demand only. They are also much shorter to write.
136 176
137Also, if you otpionally generate a lot of debug messages (such as when 177Also, if you optionally generate a lot of debug messages (such as when
138tracing some code), you should look into using a logger callback and a 178tracing some code), you should look into using a logger callback and a
139boolean enabler (see C<logger>, below). 179boolean enabler (see C<logger>, below).
140 180
141Example: log something at error level. 181Example: log something at error level.
142 182
152 192
153=cut 193=cut
154 194
155# also allow syslog equivalent names 195# also allow syslog equivalent names
156our %STR2LEVEL = ( 196our %STR2LEVEL = (
157 fatal => 1, emerg => 1, 197 fatal => 1, emerg => 1, exit => 1,
158 alert => 2, 198 alert => 2,
159 critical => 3, crit => 3, 199 critical => 3, crit => 3,
160 error => 4, err => 4, 200 error => 4, err => 4, die => 4,
161 warn => 5, warning => 5, 201 warn => 5, warning => 5,
162 note => 6, notice => 6, 202 note => 6, notice => 6,
163 info => 7, 203 info => 7,
164 debug => 8, 204 debug => 8,
165 trace => 9, 205 trace => 9,
173 213
174our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace); 214our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
175 215
176# time, ctx, level, msg 216# time, ctx, level, msg
177sub _format($$$$) { 217sub _format($$$$) {
178 my $pfx = ft $_[0]; 218 my $ts = ft $_[0];
219 my $ct = " ";
220
179 my @res; 221 my @res;
180 222
181 for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) { 223 for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
182 push @res, "$pfx $_\n"; 224 push @res, "$ts$ct$_\n";
183 $pfx = "\t"; 225 $ct = " + ";
184 } 226 }
185 227
186 join "", @res 228 join "", @res
187} 229}
188 230
189sub _log { 231sub _log {
190 my ($ctx, $level, $format, @args) = @_; 232 my ($ctx, $level, $format, @args) = @_;
191 233
234 $level = $level > 0 && $level <= 9
235 ? $level+0
192 $level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 236 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
193 237
194 my $mask = 1 << $level; 238 my $mask = 1 << $level;
195 239
196 my (@ctx, $now, $fmt); 240 my ($success, %seen, @ctx, $now, $fmt);
197 241
198 do { 242 do
243 {
199 # skip if masked 244 # skip if masked
200 next unless $ctx->[1] & $mask; 245 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
201
202 if ($ctx->[3]) { 246 if ($ctx->[3]) {
203 # logging target found 247 # logging target found
204 248
205 # now get raw message, unless we have it already 249 # now get raw message, unless we have it already
206 unless ($now) { 250 unless ($now) {
207 $format = $format->() if ref $format; 251 $format = $format->() if ref $format;
208 $format = sprintf $format, @args if @args; 252 $format = sprintf $format, @args if @args;
209 $format =~ s/\n$//; 253 $format =~ s/\n$//;
210 $now = AE::now; 254 $now = AE::now;
255 };
256
257 # format msg
258 my $str = $ctx->[4]
259 ? $ctx->[4]($now, $_[0], $level, $format)
260 : ($fmt ||= _format $now, $_[0], $level, $format);
261
262 $success = 1;
263
264 $ctx->[3]($str)
265 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
266 } else {
267 push @ctx, values %{ $ctx->[2] }; # not masked - propagate
268 }
211 }; 269 }
212
213 # format msg
214 my $str = $ctx->[4]
215 ? $ctx->[4]($now, $_[0], $level, $format)
216 : $fmt ||= _format $now, $_[0], $level, $format;
217
218 $ctx->[3]($str)
219 and next;
220 } 270 }
221
222 # not masked, not consume - propagate to parent contexts
223 push @ctx, values %{ $ctx->[2] };
224 } while $ctx = pop @ctx; 271 while $ctx = pop @ctx;
225 272
226 exit 1 if $level <= 1; 273 exit 1 if $level <= 1;
274
275 $success
227} 276}
228 277
229sub log($$;@) { 278sub log($$;@) {
230 _log 279 _log
231 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 280 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
235*AnyEvent::log = *AE::log = \&log; 284*AnyEvent::log = *AE::log = \&log;
236 285
237=item $logger = AnyEvent::Log::logger $level[, \$enabled] 286=item $logger = AnyEvent::Log::logger $level[, \$enabled]
238 287
239Creates a code reference that, when called, acts as if the 288Creates a code reference that, when called, acts as if the
240C<AnyEvent::Log::log> function was called at this point with the givne 289C<AnyEvent::Log::log> function was called at this point with the given
241level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with 290level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
242the C<AnyEvent::Log::log> function: 291the C<AnyEvent::Log::log> function:
243 292
244 my $debug_log = AnyEvent::Log::logger "debug"; 293 my $debug_log = AnyEvent::Log::logger "debug";
245 294
270 # and later in your program 319 # and later in your program
271 $debug_log->("yo, stuff here") if $debug; 320 $debug_log->("yo, stuff here") if $debug;
272 321
273 $debug and $debug_log->("123"); 322 $debug and $debug_log->("123");
274 323
275Note: currently the enabled var is always true - that will be fixed in a
276future version :)
277
278=cut 324=cut
279 325
280our %LOGGER; 326our %LOGGER;
281 327
282# re-assess logging status for all loggers 328# re-assess logging status for all loggers
283sub _reassess { 329sub _reassess {
330 local $SIG{__DIE__};
331 my $die = sub { die };
332
284 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) { 333 for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
285 my ($ctx, $level, $renabled) = @$_; 334 my ($ctx, $level, $renabled) = @$_;
286 335
287 # to detetc whether a message would be logged, we # actually 336 # to detect whether a message would be logged, we actually
288 # try to log one and die. this isn't # fast, but we can be 337 # try to log one and die. this isn't fast, but we can be
289 # sure that the logging decision is correct :) 338 # sure that the logging decision is correct :)
290 339
291 $$renabled = !eval { 340 $$renabled = !eval {
292 local $SIG{__DIE__};
293
294 _log $ctx, $level, sub { die }; 341 _log $ctx, $level, $die;
295 342
296 1 343 1
297 }; 344 };
298
299 $$renabled = 1; # TODO
300 } 345 }
301} 346}
302 347
303sub _logger($;$) { 348sub _logger {
304 my ($ctx, $level, $renabled) = @_; 349 my ($ctx, $level, $renabled) = @_;
305
306 $renabled ||= \my $enabled;
307 350
308 $$renabled = 1; 351 $$renabled = 1;
309 352
310 my $logger = [$ctx, $level, $renabled]; 353 my $logger = [$ctx, $level, $renabled];
311 354
351timestamp, context, level and string message and formats it in the way 394timestamp, context, level and string message and formats it in the way
352it should be logged) and a logging callback (which is responsible for 395it should be logged) and a logging callback (which is responsible for
353actually logging the formatted message and telling C<AnyEvent::Log> 396actually logging the formatted message and telling C<AnyEvent::Log>
354whether it has consumed the message, or whether it should be propagated). 397whether it has consumed the message, or whether it should be propagated).
355 398
356For propagation, a context can have any number of attached I<parent 399For propagation, a context can have any number of attached I<slave
357contexts>. Any message that is neither masked by the logging mask nor 400contexts>. Any message that is neither masked by the logging mask nor
358masked by the logging callback returning true will be passed to all parent 401masked by the logging callback returning true will be passed to all slave
359contexts. 402contexts.
403
404Each call to a logging function will log the message at most once per
405context, so it does not matter (much) if there are cycles or if the
406message can arrive at the same context via multiple paths.
360 407
361=head2 DEFAULTS 408=head2 DEFAULTS
362 409
363By default, all logging contexts have an full set of log levels ("all"), a 410By default, all logging contexts have an full set of log levels ("all"), a
364disabled logging callback and the default formatting callback. 411disabled logging callback and the default formatting callback.
365 412
366Package contexts have the package name as logging title by default. 413Package contexts have the package name as logging title by default.
367 414
368They have exactly one parent - the context of the "parent" package. The 415They have exactly one slave - the context of the "parent" package. The
369parent package is simply defined to be the package name without the last 416parent package is simply defined to be the package name without the last
370component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>, 417component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371and C<AnyEvent> becomes the empty string. 418and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
419exception of the rule - just like the "parent" of any single-component
420package name in Perl is C<main>, the default slave of any top-level
421package context is C<$AnyEvent::Log::COLLECT>.
372 422
373Since perl packages form only an approximate hierarchy, this parent 423Since perl packages form only an approximate hierarchy, this slave
374context can of course be removed. 424context can of course be removed.
375 425
376All other (anonymous) contexts have no parents and an empty title by 426All other (anonymous) contexts have no slaves and an empty title by
377default. 427default.
378 428
379When the module is first loaded, it configures the root context (the one 429When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
380with the empty string) to simply dump all log messages to C<STDERR>, 430context that simply logs everything via C<warn>, without propagating
381and sets it's log level set to all levels up to the one specified by 431anything anywhere by default. The purpose of this context is to provide
382C<$ENV{PERL_ANYEVENT_VERBOSE}>. 432a convenient place to override the global logging target or to attach
433additional log targets. It's not meant for filtering.
434
435It then creates the C<$AnyEvent::Log::FILTER> context whose
436purpose is to suppress all messages with priority higher
437than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
438C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
439is to simply provide filtering according to some global log level.
440
441Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
442and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
443leaves it at default config. Its purpose is simply to collect all log
444messages system-wide.
445
446The hierarchy is then:
447
448 any package, eventually -> $COLLECT -> $FILTER -> $LOG
383 449
384The effect of all this is that log messages, by default, wander up to the 450The effect of all this is that log messages, by default, wander up to the
385root context and will be logged to STDERR if their log level is less than 451C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
386or equal to C<$ENV{PERL_ANYEVENT_VERBOSE}>. 452from there to C<$AnyEvent::Log::FILTER> where log messages with lower
453priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
454to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
387 455
456This makes it easy to set a global logging level (by modifying $FILTER),
457but still allow other contexts to send, for example, their debug and trace
458messages to the $LOG target despite the global logging level, or to attach
459additional log targets that log messages, regardless of the global logging
460level.
461
462It also makes it easy to modify the default warn-logger ($LOG) to
463something that logs to a file, or to attach additional logging targets
464(such as loggign to a file) by attaching it to $FILTER.
465
388=head2 CREATING/FINDING A CONTEXT 466=head2 CREATING/FINDING/DESTROYING CONTEXTS
389 467
390=over 4 468=over 4
391 469
392=item $ctx = AnyEvent::Log::ctx [$pkg] 470=item $ctx = AnyEvent::Log::ctx [$pkg]
393 471
411 : defined $pkg 489 : defined $pkg
412 ? $CTX{$pkg} ||= AnyEvent::Log::_pkg_ctx $pkg 490 ? $CTX{$pkg} ||= AnyEvent::Log::_pkg_ctx $pkg
413 : bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx" 491 : bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
414} 492}
415 493
416# create default root context 494=item AnyEvent::Log::reset
417{ 495
418 my $root = ctx undef; 496Resets all package contexts and recreates the default hierarchy if
419 $root->[0] = ""; 497necessary, i.e. resets the logging subsystem to defaults, as much as
420 $root->title ("default"); 498possible. This process keeps references to contexts held by other parts of
421 $root->level ($AnyEvent::VERBOSE); undef $AnyEvent::VERBOSE; 499the program intact.
422 $root->log_cb (sub { 500
423 print STDERR shift; 501This can be used to implement config-file (re-)loading: before loading a
424 0 502configuration, reset all contexts.
503
504=cut
505
506sub reset {
507 # hard to kill complex data structures
508 # we "recreate" all package loggers and reset the hierarchy
509 while (my ($k, $v) = each %CTX) {
510 @$v = ($k, (1 << 10) - 1 - 1, { });
511
512 $v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
425 }); 513 }
426 $CTX{""} = $root; 514
515 @$_ = ($_->[0], (1 << 10) - 1 - 1)
516 for $LOG, $FILTER, $COLLECT;
517
518 $LOG->slaves;
519 $LOG->title ('$AnyEvent::Log::LOG');
520 $LOG->log_to_warn;
521
522 $FILTER->slaves ($LOG);
523 $FILTER->title ('$AnyEvent::Log::FILTER');
524 $FILTER->level ($AnyEvent::VERBOSE);
525
526 $COLLECT->slaves ($FILTER);
527 $COLLECT->title ('$AnyEvent::Log::COLLECT');
528
529 _reassess;
427} 530}
531
532# create the default logger contexts
533$LOG = ctx undef;
534$FILTER = ctx undef;
535$COLLECT = ctx undef;
536
537AnyEvent::Log::reset;
538
539# hello, CPAN, please catch me
540package AnyEvent::Log::LOG;
541package AE::Log::LOG;
542package AnyEvent::Log::FILTER;
543package AE::Log::FILTER;
544package AnyEvent::Log::COLLECT;
545package AE::Log::COLLECT;
546
547package AnyEvent::Log::Ctx;
548
549# 0 1 2 3 4
550# [$title, $level, %$slaves, &$logcb, &$fmtcb]
551
552=item $ctx = new AnyEvent::Log::Ctx methodname => param...
553
554This is a convenience constructor that makes it simpler to construct
555anonymous logging contexts.
556
557Each key-value pair results in an invocation of the method of the same
558name as the key with the value as parameter, unless the value is an
559arrayref, in which case it calls the method with the contents of the
560array. The methods are called in the same order as specified.
561
562Example: create a new logging context and set both the default logging
563level, some slave contexts and a logging callback.
564
565 $ctx = new AnyEvent::Log::Ctx
566 title => "dubious messages",
567 level => "error",
568 log_cb => sub { print STDOUT shift; 0 },
569 slaves => [$ctx1, $ctx, $ctx2],
570 ;
428 571
429=back 572=back
430 573
431=cut 574=cut
432 575
433package AnyEvent::Log::Ctx; 576sub new {
577 my $class = shift;
434 578
435# 0 1 2 3 4 579 my $ctx = AnyEvent::Log::ctx undef;
436# [$title, $level, %$parents, &$logcb, &$fmtcb] 580
581 while (@_) {
582 my ($k, $v) = splice @_, 0, 2;
583 $ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
584 }
585
586 bless $ctx, $class # do we really support subclassing, hmm?
587}
588
437 589
438=head2 CONFIGURING A LOG CONTEXT 590=head2 CONFIGURING A LOG CONTEXT
439 591
440The following methods can be used to configure the logging context. 592The following methods can be used to configure the logging context.
441 593
535 AnyEvent::Log::_reassess; 687 AnyEvent::Log::_reassess;
536} 688}
537 689
538=back 690=back
539 691
540=head3 PARENT CONTEXTS 692=head3 SLAVE CONTEXTS
541 693
542The following methods attach and detach another logging context to a 694The following methods attach and detach another logging context to a
543logging context. 695logging context.
544 696
545Log messages are propagated to all parent contexts, unless the logging 697Log messages are propagated to all slave contexts, unless the logging
546callback consumes the message. 698callback consumes the message.
547 699
548=over 4 700=over 4
549 701
550=item $ctx->attach ($ctx2[, $ctx3...]) 702=item $ctx->attach ($ctx2[, $ctx3...])
551 703
552Attaches the given contexts as parents to this context. It is not an error 704Attaches the given contexts as slaves to this context. It is not an error
553to add a context twice (the second add will be ignored). 705to add a context twice (the second add will be ignored).
554 706
555A context can be specified either as package name or as a context object. 707A context can be specified either as package name or as a context object.
556 708
557=item $ctx->detach ($ctx2[, $ctx3...]) 709=item $ctx->detach ($ctx2[, $ctx3...])
558 710
559Removes the given parents from this context - it's not an error to attempt 711Removes the given slaves from this context - it's not an error to attempt
560to remove a context that hasn't been added. 712to remove a context that hasn't been added.
561 713
562A context can be specified either as package name or as a context object. 714A context can be specified either as package name or as a context object.
715
716=item $ctx->slaves ($ctx2[, $ctx3...])
717
718Replaces all slaves attached to this context by the ones given.
563 719
564=cut 720=cut
565 721
566sub attach { 722sub attach {
567 my $ctx = shift; 723 my $ctx = shift;
575 731
576 delete $ctx->[2]{$_+0} 732 delete $ctx->[2]{$_+0}
577 for map { AnyEvent::Log::ctx $_ } @_; 733 for map { AnyEvent::Log::ctx $_ } @_;
578} 734}
579 735
736sub slaves {
737 undef $_[0][2];
738 &attach;
739}
740
580=back 741=back
581 742
582=head3 MESSAGE LOGGING 743=head3 LOG TARGETS
583 744
584The following methods configure how the logging context actually does 745The following methods configure how the logging context actually does
585the logging (which consists of formatting the message and printing it or 746the logging (which consists of formatting the message and printing it or
586whatever it wants to do with it) and also allows you to log messages 747whatever it wants to do with it).
587directly to a context, without going via your package context.
588 748
589=over 4 749=over 4
590 750
591=item $ctx->log_cb ($cb->($str)) 751=item $ctx->log_cb ($cb->($str)
592 752
593Replaces the logging callback on the context (C<undef> disables the 753Replaces the logging callback on the context (C<undef> disables the
594logging callback). 754logging callback).
595 755
596The logging callback is responsible for handling formatted log messages 756The logging callback is responsible for handling formatted log messages
597(see C<fmt_cb> below) - normally simple text strings that end with a 757(see C<fmt_cb> below) - normally simple text strings that end with a
598newline (and are possibly multiline themselves). 758newline (and are possibly multiline themselves).
599 759
600It also has to return true iff it has consumed the log message, and false 760It also has to return true iff it has consumed the log message, and false
601if it hasn't. Consuming a message means that it will not be sent to any 761if it hasn't. Consuming a message means that it will not be sent to any
602parent context. When in doubt, return C<0> from your logging callback. 762slave context. When in doubt, return C<0> from your logging callback.
603 763
604Example: a very simple logging callback, simply dump the message to STDOUT 764Example: a very simple logging callback, simply dump the message to STDOUT
605and do not consume it. 765and do not consume it.
606 766
607 $ctx->log_cb (sub { print STDERR shift; 0 }); 767 $ctx->log_cb (sub { print STDERR shift; 0 });
615your program. 775your program.
616 776
617 $ctx->levels ("debug", "trace"); 777 $ctx->levels ("debug", "trace");
618 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages 778 $ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
619 779
620=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message)) 780=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
621 781
622Replaces the formatting callback on the context (C<undef> restores the 782Replaces the formatting callback on the context (C<undef> restores the
623default formatter). 783default formatter).
624 784
625The callback is passed the (possibly fractional) timestamp, the original 785The callback is passed the (possibly fractional) timestamp, the original
626logging context, the (numeric) logging level and the raw message string and needs to 786logging context, the (numeric) logging level and the raw message string
627return a formatted log message. In most cases this will be a string, but 787and needs to return a formatted log message. In most cases this will be a
628it could just as well be an array reference that just stores the values. 788string, but it could just as well be an array reference that just stores
789the values.
790
791If, for some reason, you want to use C<caller> to find out more baout the
792logger then you should walk up the call stack until you are no longer
793inside the C<AnyEvent::Log> package.
629 794
630Example: format just the raw message, with numeric log level in angle 795Example: format just the raw message, with numeric log level in angle
631brackets. 796brackets.
632 797
633 $ctx->fmt_cb (sub { 798 $ctx->fmt_cb (sub {
650 "$msg->[3]"; 815 "$msg->[3]";
651 816
652 0 817 0
653 }); 818 });
654 819
820=item $ctx->log_to_warn
821
822Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
823(usually this logs to STDERR).
824
825=item $ctx->log_to_file ($path)
826
827Sets the C<log_cb> to log to a file (by appending), unbuffered.
828
829=item $ctx->log_to_path ($path)
830
831Same as C<< ->log_to_file >>, but opens the file for each message. This
832is much slower, but allows you to change/move/rename/delete the file at
833basically any time.
834
835Needless(?) to say, if you do not want to be bitten by some evil person
836calling C<chdir>, the path should be absolute. Doesn't help with
837C<chroot>, but hey...
838
839=item $ctx->log_to_syslog ([$log_flags])
840
841Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
842the others in the obvious way. If specified, then the C<$log_flags> are
843simply or'ed onto the priority argument and can contain any C<LOG_xxx>
844flags valid for Sys::Syslog::syslog, except for the priority levels.
845
846Note that this function also sets a C<fmt_cb> - the logging part requires
847an array reference with [$level, $str] as input.
848
655=cut 849=cut
656 850
657sub log_cb { 851sub log_cb {
658 my ($ctx, $cb) = @_; 852 my ($ctx, $cb) = @_;
659 853
664 my ($ctx, $cb) = @_; 858 my ($ctx, $cb) = @_;
665 859
666 $ctx->[4] = $cb; 860 $ctx->[4] = $cb;
667} 861}
668 862
863sub log_to_warn {
864 my ($ctx, $path) = @_;
865
866 $ctx->log_cb (sub {
867 warn shift;
868 0
869 });
870}
871
872sub log_to_file {
873 my ($ctx, $path) = @_;
874
875 open my $fh, ">>", $path
876 or die "$path: $!";
877
878 $ctx->log_cb (sub {
879 syswrite $fh, shift;
880 0
881 });
882}
883
884sub log_to_path {
885 my ($ctx, $path) = @_;
886
887 $ctx->log_cb (sub {
888 open my $fh, ">>", $path
889 or die "$path: $!";
890
891 syswrite $fh, shift;
892 0
893 });
894}
895
896sub log_to_syslog {
897 my ($ctx, $flags) = @_;
898
899 require Sys::Syslog;
900
901 $ctx->fmt_cb (sub {
902 my $str = $_[3];
903 $str =~ s/\n(?=.)/\n+ /g;
904
905 [$_[2], "($_[1][0]) $str"]
906 });
907
908 $ctx->log_cb (sub {
909 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
910
911 Sys::Syslog::syslog ($flags | ($lvl - 1), $_)
912 for split /\n/, $_[0][1];
913
914 0
915 });
916}
917
918=back
919
920=head3 MESSAGE LOGGING
921
922These methods allow you to log messages directly to a context, without
923going via your package context.
924
925=over 4
926
669=item $ctx->log ($level, $msg[, @params]) 927=item $ctx->log ($level, $msg[, @params])
670 928
671Same as C<AnyEvent::Log::log>, but uses the given context as log context. 929Same as C<AnyEvent::Log::log>, but uses the given context as log context.
672 930
673=item $logger = $ctx->logger ($level[, \$enabled]) 931=item $logger = $ctx->logger ($level[, \$enabled])
678=cut 936=cut
679 937
680*log = \&AnyEvent::Log::_log; 938*log = \&AnyEvent::Log::_log;
681*logger = \&AnyEvent::Log::_logger; 939*logger = \&AnyEvent::Log::_logger;
682 940
941=back
942
943=cut
944
945package AnyEvent::Log;
946
947=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
948
949Logging can also be configured by setting the environment variable
950C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
951
952The value consists of one or more logging context specifications separated
953by C<:> or whitespace. Each logging specification in turn starts with a
954context name, followed by C<=>, followed by zero or more comma-separated
955configuration directives, here are some examples:
956
957 # set default logging level
958 filter=warn
959
960 # log to file instead of to stderr
961 log=file=/tmp/mylog
962
963 # log to file in addition to stderr
964 log=+%file:%file=file=/tmp/mylog
965
966 # enable debug log messages, log warnings and above to syslog
967 filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
968
969 # log trace messages (only) from AnyEvent::Debug to file
970 AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
971
972A context name in the log specification can be any of the following:
973
974=over 4
975
976=item C<collect>, C<filter>, C<log>
977
978Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
979C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
980
981=item C<%name>
982
983Context names starting with a C<%> are anonymous contexts created when the
984name is first mentioned. The difference to package contexts is that by
985default they have no attached slaves.
986
987=item a perl package name
988
989Any other string references the logging context associated with the given
990Perl C<package>. In the unlikely case where you want to specify a package
991context that matches on of the other context name forms, you can add a
992C<::> to the package name to force interpretation as a package.
993
994=back
995
996The configuration specifications can be any number of the following:
997
998=over 4
999
1000=item C<stderr>
1001
1002Configures the context to use Perl's C<warn> function (which typically
1003logs to C<STDERR>). Works like C<log_to_warn>.
1004
1005=item C<file=>I<path>
1006
1007Configures the context to log to a file with the given path. Works like
1008C<log_to_file>.
1009
1010=item C<path=>I<path>
1011
1012Configures the context to log to a file with the given path. Works like
1013C<log_to_path>.
1014
1015=item C<syslog> or C<syslog=>I<expr>
1016
1017Configured the context to log to syslog. If I<expr> is given, then it is
1018evaluated in the L<Sys::Syslog> package, so you could use:
1019
1020 log=syslog=LOG_LOCAL0
1021
1022=item C<nolog>
1023
1024Configures the context to not log anything by itself, which is the
1025default. Same as C<< $ctx->log_cb (undef) >>.
1026
1027=item C<0> or C<off>
1028
1029Sets the logging level of the context ot C<0>, i.e. all messages will be
1030filtered out.
1031
1032=item C<all>
1033
1034Enables all logging levels, i.e. filtering will effectively be switched
1035off (the default).
1036
1037=item C<only>
1038
1039Disables all logging levels, and changes the interpretation of following
1040level specifications to enable the specified level only.
1041
1042Example: only enable debug messages for a context.
1043
1044 context=only,debug
1045
1046=item C<except>
1047
1048Enables all logging levels, and changes the interpretation of following
1049level specifications to disable that level. Rarely used.
1050
1051Example: enable all logging levels except fatal and trace (this is rather
1052nonsensical).
1053
1054 filter=exept,fatal,trace
1055
1056=item C<level>
1057
1058Enables all logging levels, and changes the interpretation of following
1059level specifications to be "that level or any higher priority
1060message". This is the default.
1061
1062Example: log anything at or above warn level.
1063
1064 filter=warn
1065
1066 # or, more verbose
1067 filter=only,level,warn
1068
1069=item C<1>..C<9>, a logging level name (C<error>, C<debug> etc.)
1070
1071A numeric loglevel or the name of a loglevel will be interpreted according
1072to the most recent C<only>, C<except> or C<level> directive. By default,
1073specifying a logging level enables that and any higher priority messages.
1074
1075=item C<+>I<context>
1076
1077Adds/attaches the named context as slave to the context.
1078
1079=item C<+>
1080
1081A line C<+> clears the slave list form the context. Anonymous (C<%name>)
1082contexts have no slaves by default, but package contexts have the parent
1083context as slave by default.
1084
1085Example: log messages from My::Module to a file, do not send them to the
1086default log collector.
1087
1088 My::Module=+,file=/tmp/mymodulelog
1089
1090=back
1091
1092Any character can be escaped by prefixing it with a C<\> (backslash), as
1093usual, so to log to a file containing a comma, colon, backslash and space in the
1094filename, you would do this:
1095
1096 PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
1097
1098Since whitespace (which includes newlines) is allowed, it is fine to
1099specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
1100
1101 PERL_ANYEVENT_LOG="
1102 filter=warn
1103 AnyEvent::Debug=+%trace
1104 %trace=only,trace,+log
1105 " myprog
1106
1107Also, in the unlikely case when you want to concatenate specifications,
1108use whitespace as separator, as C<::> will be interpreted as part of a
1109module name, an empty spec with two separators:
1110
1111 PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
1112
1113=cut
1114
1115for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
1116 my %anon;
1117
1118 my $pkg = sub {
1119 $_[0] eq "log" ? $LOG
1120 : $_[0] eq "filter" ? $FILTER
1121 : $_[0] eq "collect" ? $COLLECT
1122 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef)
1123 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1124 : die # never reached?
1125 };
1126
1127 /\G[[:space:]]+/gc; # skip initial whitespace
1128
1129 while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
1130 my $ctx = $pkg->($1);
1131 my $level = "level";
1132
1133 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1134 for ("$1") {
1135 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1136 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1137 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1138 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
1139 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1140 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1141 } elsif ($_ eq "+" ) { $ctx->slaves;
1142 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1143 } elsif ($_ eq "all" ) { $ctx->level ("all");
1144 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1145 } elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
1146 } elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
1147 } elsif (/^\d$/ ) { $ctx->$level ($_);
1148 } elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
1149 } else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
1150 }
1151 }
1152
1153 /\G,/gc or last;
1154 }
1155
1156 /\G[:[:space:]]+/gc or last;
1157 }
1158
1159 /\G[[:space:]]+/gc; # skip trailing whitespace
1160
1161 if (/\G(.+)/g) {
1162 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1163 }
1164}
1165
6831; 11661;
1167
1168=head1 EXAMPLES
1169
1170This section shows some common configurations, both as code, and as
1171C<PERL_ANYEVENT_LOG> string.
1172
1173=over 4
1174
1175=item Setting the global logging level.
1176
1177Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
1178running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
1179the root context at runtime:
1180
1181 PERL_ANYEVENT_VERBOSE=5 ./myprog
1182
1183 PERL_ANYEVENT_LOG=log=warn
1184
1185 $AnyEvent::Log::FILTER->level ("warn");
1186
1187=item Append all messages to a file instead of sending them to STDERR.
1188
1189This is affected by the global logging level.
1190
1191 $AnyEvent::Log::LOG->log_to_file ($path);
1192
1193 PERL_ANYEVENT_LOG=log=file=/some/path
1194
1195=item Write all messages with priority C<error> and higher to a file.
1196
1197This writes them only when the global logging level allows it, because
1198it is attached to the default context which is invoked I<after> global
1199filtering.
1200
1201 $AnyEvent::Log::FILTER->attach
1202 new AnyEvent::Log::Ctx log_to_file => $path);
1203
1204 PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
1205
1206This writes them regardless of the global logging level, because it is
1207attached to the toplevel context, which receives all messages I<before>
1208the global filtering.
1209
1210 $AnyEvent::Log::COLLECT->attach (
1211 new AnyEvent::Log::Ctx log_to_file => $path);
1212
1213 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1214
1215In both cases, messages are still written to STDERR.
1216
1217=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
1218
1219Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
1220context - this simply circumvents the global filtering for trace messages.
1221
1222 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
1223 $debug->attach ($AnyEvent::Log::LOG);
1224
1225 PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
1226
1227This of course works for any package, not just L<AnyEvent::Debug>, but
1228assumes the log level for AnyEvent::Debug hasn't been changed from the
1229default.
684 1230
685=back 1231=back
686 1232
687=head1 AUTHOR 1233=head1 AUTHOR
688 1234
689 Marc Lehmann <schmorp@schmorp.de> 1235 Marc Lehmann <schmorp@schmorp.de>
690 http://home.schmorp.de/ 1236 http://home.schmorp.de/
691 1237
692=cut 1238=cut
1239

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