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Revision 1.21 by root, Sat Aug 20 22:33:08 2011 UTC vs.
Revision 1.43 by root, Mon Sep 5 07:21:54 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 # available log levels in order:
17 # fatal alert critical error warn note info debug trace
18
19"Complex" uses (for speed sensitive code):
20
16 use AnyEvent::Log; 21 use AnyEvent::Log;
17 22
18 my $tracer = AnyEvent::Log::logger trace => \$my $trace; 23 my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19 24
20 $tracer->("i am here") if $trace; 25 $tracer->("i am here") if $trace;
21 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace; 26 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22 27
23 # configuration 28Configuration (also look at the EXAMPLES section):
24 29
25 # set logging for the current package to errors and higher only 30 # set logging for the current package to errors and higher only
26 AnyEvent::Log::ctx->level ("error"); 31 AnyEvent::Log::ctx->level ("error");
27 32
28 # set logging globally to anything below debug 33 # set logging level to suppress anything below "notice"
29 $AnyEvent::Log::FILTER->level ("notice"); 34 $AnyEvent::Log::FILTER->level ("notice");
30 35
31 # see also EXAMPLES, below 36 # send all critical and higher priority messages to syslog,
37 # regardless of (most) other settings
38 $AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
39 level => "critical",
40 log_to_syslog => "user",
41 );
32 42
33=head1 DESCRIPTION 43=head1 DESCRIPTION
34 44
35This module implements a relatively simple "logging framework". It doesn't 45This module implements a relatively simple "logging framework". It doesn't
36attempt to be "the" logging solution or even "a" logging solution for 46attempt to be "the" logging solution or even "a" logging solution for
42will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number 52will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
43before starting your program, or change the logging level at runtime with 53before starting your program, or change the logging level at runtime with
44something like: 54something like:
45 55
46 use AnyEvent::Log; 56 use AnyEvent::Log;
47 AnyEvent::Log::FILTER->level ("info"); 57 $AnyEvent::Log::FILTER->level ("info");
48 58
49The design goal behind this module was to keep it simple (and small), 59The design goal behind this module was to keep it simple (and small),
50but make it powerful enough to be potentially useful for any module, and 60but make it powerful enough to be potentially useful for any module, and
51extensive enough for the most common tasks, such as logging to multiple 61extensive enough for the most common tasks, such as logging to multiple
52targets, or being able to log into a database. 62targets, or being able to log into a database.
53 63
64The module is also usable before AnyEvent itself is initialised, in which
65case some of the functionality might be reduced.
66
54The amount of documentation might indicate otherwise, but the module is 67The amount of documentation might indicate otherwise, but the runtime part
55still just below 300 lines of code. 68of the module is still just below 300 lines of code.
56 69
57=head1 LOGGING LEVELS 70=head1 LOGGING LEVELS
58 71
59Logging levels in this module range from C<1> (highest priority) to C<9> 72Logging levels in this module range from C<1> (highest priority) to C<9>
60(lowest priority). Note that the lowest numerical value is the highest 73(lowest priority). Note that the lowest numerical value is the highest
62numerical value". 75numerical value".
63 76
64Instead of specifying levels by name you can also specify them by aliases: 77Instead of specifying levels by name you can also specify them by aliases:
65 78
66 LVL NAME SYSLOG PERL NOTE 79 LVL NAME SYSLOG PERL NOTE
67 1 fatal emerg exit aborts program! 80 1 fatal emerg exit system unusable, aborts program!
68 2 alert 81 2 alert failure in primary system
69 3 critical crit 82 3 critical crit failure in backup system
70 4 error err die 83 4 error err die non-urgent program errors, a bug
71 5 warn warning 84 5 warn warning possible problem, not necessarily error
72 6 note notice 85 6 note notice unusual conditions
73 7 info 86 7 info normal messages, no action required
74 8 debug 87 8 debug debugging messages for development
75 9 trace 88 9 trace copious tracing output
76 89
77As you can see, some logging levels have multiple aliases - the first one 90As you can see, some logging levels have multiple aliases - the first one
78is the "official" name, the second one the "syslog" name (if it differs) 91is the "official" name, the second one the "syslog" name (if it differs)
79and the third one the "perl" name, suggesting that you log C<die> messages 92and the third one the "perl" name, suggesting (only!) that you log C<die>
80at C<error> priority. 93messages at C<error> priority. The NOTE column tries to provide some
94rationale on how to chose a logging level.
95
96As a rough guideline, levels 1..3 are primarily meant for users of
97the program (admins, staff), and are the only logged to STDERR by
98default. Levels 4..6 are meant for users and developers alike, while
99levels 7..9 are usually meant for developers.
81 100
82You can normally only log a single message at highest priority level 101You can normally only log a single message at highest priority level
83(C<1>, C<fatal>), because logging a fatal message will also quit the 102(C<1>, C<fatal>), because logging a fatal message will also quit the
84program - so use it sparingly :) 103program - so use it sparingly :)
85 104
101 120
102use Carp (); 121use Carp ();
103use POSIX (); 122use POSIX ();
104 123
105use AnyEvent (); BEGIN { AnyEvent::common_sense } 124use AnyEvent (); BEGIN { AnyEvent::common_sense }
106use AnyEvent::Util (); 125#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
107 126
108our $VERSION = $AnyEvent::VERSION; 127our $VERSION = $AnyEvent::VERSION;
109 128
110our ($COLLECT, $FILTER, $LOG); 129our ($COLLECT, $FILTER, $LOG);
111 130
138 $ctx 157 $ctx
139} 158}
140 159
141=item AnyEvent::Log::log $level, $msg[, @args] 160=item AnyEvent::Log::log $level, $msg[, @args]
142 161
143Requests logging of the given C<$msg> with the given log level. 162Requests logging of the given C<$msg> with the given log level, and
163returns true if the message was logged I<somewhere>.
144 164
145For C<fatal> log levels, the program will abort. 165For loglevel C<fatal>, the program will abort.
146 166
147If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the 167If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
148C<$msg> is interpreted as an sprintf format string. 168C<$msg> is interpreted as an sprintf format string.
149 169
150The C<$msg> should not end with C<\n>, but may if that is convenient for 170The C<$msg> should not end with C<\n>, but may if that is convenient for
154supposed to return the message. It will be called only then the message 174supposed to return the message. It will be called only then the message
155actually gets logged, which is useful if it is costly to create the 175actually gets logged, which is useful if it is costly to create the
156message in the first place. 176message in the first place.
157 177
158Whether the given message will be logged depends on the maximum log level 178Whether the given message will be logged depends on the maximum log level
159and the caller's package. 179and the caller's package. The return value can be used to ensure that
180messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
181runtime error it tries to log it at C<die> level, but if that message is
182lost it simply uses warn.
160 183
161Note that you can (and should) call this function as C<AnyEvent::log> or 184Note that you can (and should) call this function as C<AnyEvent::log> or
162C<AE::log>, without C<use>-ing this module if possible (i.e. you don't 185C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
163need any additional functionality), as those functions will load the 186need any additional functionality), as those functions will load the
164logging module on demand only. They are also much shorter to write. 187logging module on demand only. They are also much shorter to write.
192 info => 7, 215 info => 7,
193 debug => 8, 216 debug => 8,
194 trace => 9, 217 trace => 9,
195); 218);
196 219
197sub now () { time } 220our $TIME_EXACT;
221
222sub exact_time($) {
223 $TIME_EXACT = shift;
224 *_ts = $AnyEvent::MODEL
225 ? $TIME_EXACT ? \&AE::now : \&AE::time
226 : sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
227}
228
229BEGIN {
230 exact_time 0;
231}
198 232
199AnyEvent::post_detect { 233AnyEvent::post_detect {
200 *now = \&AE::now; 234 exact_time $TIME_EXACT;
201}; 235};
202 236
203our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace); 237our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
204 238
205# time, ctx, level, msg 239# time, ctx, level, msg
215 } 249 }
216 250
217 join "", @res 251 join "", @res
218} 252}
219 253
254sub fatal_exit() {
255 exit 1;
256}
257
220sub _log { 258sub _log {
221 my ($ctx, $level, $format, @args) = @_; 259 my ($ctx, $level, $format, @args) = @_;
222 260
223 $level = $level > 0 && $level <= 9 261 $level = $level > 0 && $level <= 9
224 ? $level+0 262 ? $level+0
225 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 263 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
226 264
227 my $mask = 1 << $level; 265 my $mask = 1 << $level;
228 266
229 my (%seen, @ctx, $now, $fmt); 267 my ($success, %seen, @ctx, $now, $fmt);
230 268
231 do 269 do
232 { 270 {
233 # skip if masked 271 # skip if masked
234 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) { 272 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
238 # now get raw message, unless we have it already 276 # now get raw message, unless we have it already
239 unless ($now) { 277 unless ($now) {
240 $format = $format->() if ref $format; 278 $format = $format->() if ref $format;
241 $format = sprintf $format, @args if @args; 279 $format = sprintf $format, @args if @args;
242 $format =~ s/\n$//; 280 $format =~ s/\n$//;
243 $now = AE::now; 281 $now = _ts;
244 }; 282 };
245 283
246 # format msg 284 # format msg
247 my $str = $ctx->[4] 285 my $str = $ctx->[4]
248 ? $ctx->[4]($now, $_[0], $level, $format) 286 ? $ctx->[4]($now, $_[0], $level, $format)
249 : ($fmt ||= _format $now, $_[0], $level, $format); 287 : ($fmt ||= _format $now, $_[0], $level, $format);
288
289 $success = 1;
250 290
251 $ctx->[3]($str) 291 $ctx->[3]($str)
252 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate 292 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
253 } else { 293 } else {
254 push @ctx, values %{ $ctx->[2] }; # not masked - propagate 294 push @ctx, values %{ $ctx->[2] }; # not masked - propagate
255 } 295 }
256 } 296 }
257 } 297 }
258 while $ctx = pop @ctx; 298 while $ctx = pop @ctx;
259 299
260 exit 1 if $level <= 1; 300 fatal_exit if $level <= 1;
301
302 $success
261} 303}
262 304
263sub log($$;@) { 305sub log($$;@) {
264 _log 306 _log
265 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 307 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
266 @_; 308 @_;
267} 309}
268 310
269*AnyEvent::log = *AE::log = \&log;
270
271=item $logger = AnyEvent::Log::logger $level[, \$enabled] 311=item $logger = AnyEvent::Log::logger $level[, \$enabled]
272 312
273Creates a code reference that, when called, acts as if the 313Creates a code reference that, when called, acts as if the
274C<AnyEvent::Log::log> function was called at this point with the givne 314C<AnyEvent::Log::log> function was called at this point with the given
275level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with 315level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
276the C<AnyEvent::Log::log> function: 316the C<AnyEvent::Log::log> function:
277 317
278 my $debug_log = AnyEvent::Log::logger "debug"; 318 my $debug_log = AnyEvent::Log::logger "debug";
279 319
339 379
340 $LOGGER{$logger+0} = $logger; 380 $LOGGER{$logger+0} = $logger;
341 381
342 _reassess $logger+0; 382 _reassess $logger+0;
343 383
384 require AnyEvent::Util unless $AnyEvent::Util::VERSION;
344 my $guard = AnyEvent::Util::guard { 385 my $guard = AnyEvent::Util::guard (sub {
345 # "clean up" 386 # "clean up"
346 delete $LOGGER{$logger+0}; 387 delete $LOGGER{$logger+0};
347 }; 388 });
348 389
349 sub { 390 sub {
350 $guard if 0; # keep guard alive, but don't cause runtime overhead 391 $guard if 0; # keep guard alive, but don't cause runtime overhead
351 392
352 _log $ctx, $level, @_ 393 _log $ctx, $level, @_
357sub logger($;$) { 398sub logger($;$) {
358 _logger 399 _logger
359 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0], 400 $CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
360 @_ 401 @_
361} 402}
403
404=item AnyEvent::Log::exact_time $on
405
406By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
407eventloop time, for the log timestamps. After calling this function with a
408true value it will instead resort to C<AE::time>, i.e. fetch the current
409time on each log message. This only makes a difference for event loops
410that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
411
412This setting can be changed at any time by calling this function.
413
414Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
415initialised, this switch will also decide whether to use C<CORE::time> or
416C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
417available.
362 418
363=back 419=back
364 420
365=head1 LOGGING CONTEXTS 421=head1 LOGGING CONTEXTS
366 422
486This can be used to implement config-file (re-)loading: before loading a 542This can be used to implement config-file (re-)loading: before loading a
487configuration, reset all contexts. 543configuration, reset all contexts.
488 544
489=cut 545=cut
490 546
547our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
548$AnyEvent::VERBOSE = 9;
549
491sub reset { 550sub reset {
492 # hard to kill complex data structures 551 # hard to kill complex data structures
493 # we "recreate" all package loggers and reset the hierarchy 552 # we "recreate" all package loggers and reset the hierarchy
494 while (my ($k, $v) = each %CTX) { 553 while (my ($k, $v) = each %CTX) {
495 @$v = ($k, (1 << 10) - 1 - 1, { }); 554 @$v = ($k, (1 << 10) - 1 - 1, { });
498 } 557 }
499 558
500 @$_ = ($_->[0], (1 << 10) - 1 - 1) 559 @$_ = ($_->[0], (1 << 10) - 1 - 1)
501 for $LOG, $FILTER, $COLLECT; 560 for $LOG, $FILTER, $COLLECT;
502 561
503 $LOG->slaves; 562 #$LOG->slaves;
504 $LOG->title ('$AnyEvent::Log::LOG'); 563 $LOG->title ('$AnyEvent::Log::LOG');
505 $LOG->log_cb (sub { 564 $LOG->log_to_warn;
506 warn shift;
507 0
508 });
509 565
510 $FILTER->slaves ($LOG); 566 $FILTER->slaves ($LOG);
511 $FILTER->title ('$AnyEvent::Log::FILTER'); 567 $FILTER->title ('$AnyEvent::Log::FILTER');
512 $FILTER->level ($AnyEvent::VERBOSE); 568 $FILTER->level ($ORIG_VERBOSE);
513 569
514 $COLLECT->slaves ($FILTER); 570 $COLLECT->slaves ($FILTER);
515 $COLLECT->title ('$AnyEvent::Log::COLLECT'); 571 $COLLECT->title ('$AnyEvent::Log::COLLECT');
516 572
517 _reassess; 573 _reassess;
518} 574}
575
576# override AE::log/logger
577*AnyEvent::log = *AE::log = \&log;
578*AnyEvent::logger = *AE::logger = \&logger;
579
580# convert AnyEvent loggers to AnyEvent::Log loggers
581$_->[0] = ctx $_->[0] # convert "pkg" to "ctx"
582 for values %LOGGER;
519 583
520# create the default logger contexts 584# create the default logger contexts
521$LOG = ctx undef; 585$LOG = ctx undef;
522$FILTER = ctx undef; 586$FILTER = ctx undef;
523$COLLECT = ctx undef; 587$COLLECT = ctx undef;
774logging context, the (numeric) logging level and the raw message string 838logging context, the (numeric) logging level and the raw message string
775and needs to return a formatted log message. In most cases this will be a 839and needs to return a formatted log message. In most cases this will be a
776string, but it could just as well be an array reference that just stores 840string, but it could just as well be an array reference that just stores
777the values. 841the values.
778 842
779If, for some reaosn, you want to use C<caller> to find out more baout the 843If, for some reason, you want to use C<caller> to find out more baout the
780logger then you should walk up the call stack until you are no longer 844logger then you should walk up the call stack until you are no longer
781inside the C<AnyEvent::Log> package. 845inside the C<AnyEvent::Log> package.
782 846
783Example: format just the raw message, with numeric log level in angle 847Example: format just the raw message, with numeric log level in angle
784brackets. 848brackets.
803 "$msg->[3]"; 867 "$msg->[3]";
804 868
805 0 869 0
806 }); 870 });
807 871
872=item $ctx->log_to_warn
873
874Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
875(usually this logs to STDERR).
876
808=item $ctx->log_to_file ($path) 877=item $ctx->log_to_file ($path)
809 878
810Sets the C<log_cb> to log to a file (by appending), unbuffered. 879Sets the C<log_cb> to log to a file (by appending), unbuffered.
811 880
812=item $ctx->log_to_path ($path) 881=item $ctx->log_to_path ($path)
813 882
814Same as C<< ->log_to_file >>, but opens the file for each message. This 883Same as C<< ->log_to_file >>, but opens the file for each message. This
815is much slower, but allows you to change/move/rename/delete the file at 884is much slower, but allows you to change/move/rename/delete the file at
816basically any time. 885basically any time.
817 886
887Needless(?) to say, if you do not want to be bitten by some evil person
888calling C<chdir>, the path should be absolute. Doesn't help with
889C<chroot>, but hey...
890
818=item $ctx->log_to_syslog ([$log_flags]) 891=item $ctx->log_to_syslog ([$facility])
819 892
820Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all 893Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
821the others in the obvious way. If specified, then the C<$log_flags> are 894all the others in the obvious way. If specified, then the C<$facility> is
822simply or'ed onto the priority argument and can contain any C<LOG_xxx> 895used as the facility (C<user>, C<auth>, C<local0> and so on). The default
823flags valid for Sys::Syslog::syslog, except for the priority levels. 896facility is C<user>.
824 897
825Note that this function also sets a C<fmt_cb> - the logging part requires 898Note that this function also sets a C<fmt_cb> - the logging part requires
826an array reference with [$level, $str] as input. 899an array reference with [$level, $str] as input.
827 900
828=cut 901=cut
835 908
836sub fmt_cb { 909sub fmt_cb {
837 my ($ctx, $cb) = @_; 910 my ($ctx, $cb) = @_;
838 911
839 $ctx->[4] = $cb; 912 $ctx->[4] = $cb;
913}
914
915sub log_to_warn {
916 my ($ctx, $path) = @_;
917
918 $ctx->log_cb (sub {
919 warn shift;
920 0
921 });
840} 922}
841 923
842sub log_to_file { 924sub log_to_file {
843 my ($ctx, $path) = @_; 925 my ($ctx, $path) = @_;
844 926
849 syswrite $fh, shift; 931 syswrite $fh, shift;
850 0 932 0
851 }); 933 });
852} 934}
853 935
854sub log_to_file { 936sub log_to_path {
855 my ($ctx, $path) = @_; 937 my ($ctx, $path) = @_;
856 938
857 $ctx->log_cb (sub { 939 $ctx->log_cb (sub {
858 open my $fh, ">>", $path 940 open my $fh, ">>", $path
859 or die "$path: $!"; 941 or die "$path: $!";
862 0 944 0
863 }); 945 });
864} 946}
865 947
866sub log_to_syslog { 948sub log_to_syslog {
867 my ($ctx, $flags) = @_; 949 my ($ctx, $facility) = @_;
868 950
869 require Sys::Syslog; 951 require Sys::Syslog;
870 952
871 $ctx->fmt_cb (sub { 953 $ctx->fmt_cb (sub {
872 my $str = $_[3]; 954 my $str = $_[3];
873 $str =~ s/\n(?=.)/\n+ /g; 955 $str =~ s/\n(?=.)/\n+ /g;
874 956
875 [$_[2], "($_[1][0]) $str"] 957 [$_[2], "($_[1][0]) $str"]
876 }); 958 });
877 959
960 $facility ||= "user";
961
878 $ctx->log_cb (sub { 962 $ctx->log_cb (sub {
879 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8; 963 my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
880 964
881 Sys::Syslog::syslog ($flags | ($lvl - 1), $_) 965 Sys::Syslog::syslog ("$facility|" . ($lvl - 1), $_)
882 for split /\n/, $_[0][1]; 966 for split /\n/, $_[0][1];
883 967
884 0 968 0
885 }); 969 });
886} 970}
906=cut 990=cut
907 991
908*log = \&AnyEvent::Log::_log; 992*log = \&AnyEvent::Log::_log;
909*logger = \&AnyEvent::Log::_logger; 993*logger = \&AnyEvent::Log::_logger;
910 994
995=back
996
997=cut
998
999package AnyEvent::Log;
1000
1001=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
1002
1003Logging can also be configured by setting the environment variable
1004C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
1005
1006The value consists of one or more logging context specifications separated
1007by C<:> or whitespace. Each logging specification in turn starts with a
1008context name, followed by C<=>, followed by zero or more comma-separated
1009configuration directives, here are some examples:
1010
1011 # set default logging level
1012 filter=warn
1013
1014 # log to file instead of to stderr
1015 log=file=/tmp/mylog
1016
1017 # log to file in addition to stderr
1018 log=+%file:%file=file=/tmp/mylog
1019
1020 # enable debug log messages, log warnings and above to syslog
1021 filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
1022
1023 # log trace messages (only) from AnyEvent::Debug to file
1024 AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
1025
1026A context name in the log specification can be any of the following:
1027
1028=over 4
1029
1030=item C<collect>, C<filter>, C<log>
1031
1032Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
1033C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
1034
1035=item C<%name>
1036
1037Context names starting with a C<%> are anonymous contexts created when the
1038name is first mentioned. The difference to package contexts is that by
1039default they have no attached slaves.
1040
1041=item a perl package name
1042
1043Any other string references the logging context associated with the given
1044Perl C<package>. In the unlikely case where you want to specify a package
1045context that matches on of the other context name forms, you can add a
1046C<::> to the package name to force interpretation as a package.
1047
1048=back
1049
1050The configuration specifications can be any number of the following:
1051
1052=over 4
1053
1054=item C<stderr>
1055
1056Configures the context to use Perl's C<warn> function (which typically
1057logs to C<STDERR>). Works like C<log_to_warn>.
1058
1059=item C<file=>I<path>
1060
1061Configures the context to log to a file with the given path. Works like
1062C<log_to_file>.
1063
1064=item C<path=>I<path>
1065
1066Configures the context to log to a file with the given path. Works like
1067C<log_to_path>.
1068
1069=item C<syslog> or C<syslog=>I<expr>
1070
1071Configures the context to log to syslog. If I<expr> is given, then it is
1072evaluated in the L<Sys::Syslog> package, so you could use:
1073
1074 log=syslog=LOG_LOCAL0
1075
1076=item C<nolog>
1077
1078Configures the context to not log anything by itself, which is the
1079default. Same as C<< $ctx->log_cb (undef) >>.
1080
1081=item C<0> or C<off>
1082
1083Sets the logging level of the context ot C<0>, i.e. all messages will be
1084filtered out.
1085
1086=item C<all>
1087
1088Enables all logging levels, i.e. filtering will effectively be switched
1089off (the default).
1090
1091=item C<only>
1092
1093Disables all logging levels, and changes the interpretation of following
1094level specifications to enable the specified level only.
1095
1096Example: only enable debug messages for a context.
1097
1098 context=only,debug
1099
1100=item C<except>
1101
1102Enables all logging levels, and changes the interpretation of following
1103level specifications to disable that level. Rarely used.
1104
1105Example: enable all logging levels except fatal and trace (this is rather
1106nonsensical).
1107
1108 filter=exept,fatal,trace
1109
1110=item C<level>
1111
1112Enables all logging levels, and changes the interpretation of following
1113level specifications to be "that level or any higher priority
1114message". This is the default.
1115
1116Example: log anything at or above warn level.
1117
1118 filter=warn
1119
1120 # or, more verbose
1121 filter=only,level,warn
1122
1123=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
1124
1125A numeric loglevel or the name of a loglevel will be interpreted according
1126to the most recent C<only>, C<except> or C<level> directive. By default,
1127specifying a logging level enables that and any higher priority messages.
1128
1129=item C<+>I<context>
1130
1131Attaches the named context as slave to the context.
1132
1133=item C<+>
1134
1135A line C<+> detaches all contexts, i.e. clears the slave list from the
1136context. Anonymous (C<%name>) contexts have no attached slaves by default,
1137but package contexts have the parent context as slave by default.
1138
1139Example: log messages from My::Module to a file, do not send them to the
1140default log collector.
1141
1142 My::Module=+,file=/tmp/mymodulelog
1143
1144=back
1145
1146Any character can be escaped by prefixing it with a C<\> (backslash), as
1147usual, so to log to a file containing a comma, colon, backslash and some
1148spaces in the filename, you would do this:
1149
1150 PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
1151
1152Since whitespace (which includes newlines) is allowed, it is fine to
1153specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
1154
1155 PERL_ANYEVENT_LOG="
1156 filter=warn
1157 AnyEvent::Debug=+%trace
1158 %trace=only,trace,+log
1159 " myprog
1160
1161Also, in the unlikely case when you want to concatenate specifications,
1162use whitespace as separator, as C<::> will be interpreted as part of a
1163module name, an empty spec with two separators:
1164
1165 PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
1166
1167=cut
1168
1169for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
1170 my %anon;
1171
1172 my $pkg = sub {
1173 $_[0] eq "log" ? $LOG
1174 : $_[0] eq "filter" ? $FILTER
1175 : $_[0] eq "collect" ? $COLLECT
1176 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef)
1177 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1178 : die # never reached?
1179 };
1180
1181 /\G[[:space:]]+/gc; # skip initial whitespace
1182
1183 while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
1184 my $ctx = $pkg->($1);
1185 my $level = "level";
1186
1187 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1188 for ("$1") {
1189 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1190 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1191 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1192 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ($1);
1193 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1194 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1195 } elsif ($_ eq "+" ) { $ctx->slaves;
1196 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1197 } elsif ($_ eq "all" ) { $ctx->level ("all");
1198 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1199 } elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
1200 } elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
1201 } elsif (/^\d$/ ) { $ctx->$level ($_);
1202 } elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
1203 } else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
1204 }
1205 }
1206
1207 /\G,/gc or last;
1208 }
1209
1210 /\G[:[:space:]]+/gc or last;
1211 }
1212
1213 /\G[[:space:]]+/gc; # skip trailing whitespace
1214
1215 if (/\G(.+)/g) {
1216 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1217 }
1218}
1219
9111; 12201;
912 1221
913=back
914
915=head1 EXAMPLES 1222=head1 EXAMPLES
916 1223
917This section shows some common configurations. 1224This section shows some common configurations, both as code, and as
1225C<PERL_ANYEVENT_LOG> string.
918 1226
919=over 4 1227=over 4
920 1228
921=item Setting the global logging level. 1229=item Setting the global logging level.
922 1230
923Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before 1231Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
924running your program, or modify the log level of the root context: 1232running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
1233the root context at runtime:
925 1234
926 PERL_ANYEVENT_VERBOSE=5 ./myprog 1235 PERL_ANYEVENT_VERBOSE=5 ./myprog
927 1236
1237 PERL_ANYEVENT_LOG=log=warn
1238
928 $AnyEvent::Log::FILTER->level ("warn"); 1239 $AnyEvent::Log::FILTER->level ("warn");
929 1240
930=item Append all messages to a file instead of sending them to STDERR. 1241=item Append all messages to a file instead of sending them to STDERR.
931 1242
932This is affected by the global logging level. 1243This is affected by the global logging level.
933 1244
934 $AnyEvent::Log::LOG->log_to_file ($path); (sub { 1245 $AnyEvent::Log::LOG->log_to_file ($path);
1246
1247 PERL_ANYEVENT_LOG=log=file=/some/path
935 1248
936=item Write all messages with priority C<error> and higher to a file. 1249=item Write all messages with priority C<error> and higher to a file.
937 1250
938This writes them only when the global logging level allows it, because 1251This writes them only when the global logging level allows it, because
939it is attached to the default context which is invoked I<after> global 1252it is attached to the default context which is invoked I<after> global
940filtering. 1253filtering.
941 1254
942 $AnyEvent::Log::FILTER->attach 1255 $AnyEvent::Log::FILTER->attach (
943 new AnyEvent::Log::Ctx log_to_file => $path); 1256 new AnyEvent::Log::Ctx log_to_file => $path);
1257
1258 PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
944 1259
945This writes them regardless of the global logging level, because it is 1260This writes them regardless of the global logging level, because it is
946attached to the toplevel context, which receives all messages I<before> 1261attached to the toplevel context, which receives all messages I<before>
947the global filtering. 1262the global filtering.
948 1263
949 $AnyEvent::Log::COLLECT->attach ( 1264 $AnyEvent::Log::COLLECT->attach (
950 new AnyEvent::Log::Ctx log_to_file => $path); 1265 new AnyEvent::Log::Ctx log_to_file => $path);
951 1266
1267 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1268
952In both cases, messages are still written to STDERR. 1269In both cases, messages are still written to STDERR.
953 1270
954=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s). 1271=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
955 1272
956Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug> 1273Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
957context - this simply circumvents the global filtering for trace messages. 1274context - this simply circumvents the global filtering for trace messages.
958 1275
959 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx; 1276 my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
960 $debug->attach ($AnyEvent::Log::LOG); 1277 $debug->attach ($AnyEvent::Log::LOG);
1278
1279 PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
961 1280
962This of course works for any package, not just L<AnyEvent::Debug>, but 1281This of course works for any package, not just L<AnyEvent::Debug>, but
963assumes the log level for AnyEvent::Debug hasn't been changed from the 1282assumes the log level for AnyEvent::Debug hasn't been changed from the
964default. 1283default.
965 1284
969 1288
970 Marc Lehmann <schmorp@schmorp.de> 1289 Marc Lehmann <schmorp@schmorp.de>
971 http://home.schmorp.de/ 1290 http://home.schmorp.de/
972 1291
973=cut 1292=cut
1293

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