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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.44 by root, Mon Sep 26 11:32:19 2011 UTC vs.
Revision 1.73 by root, Sun Apr 24 21:22:38 2022 UTC

6 6
7Simple uses: 7Simple uses:
8 8
9 use AnyEvent; 9 use AnyEvent;
10 10
11 AE::log fatal => "No config found, cannot continue!"; # never returns
12 AE::log alert => "The battery died!";
13 AE::log crit => "The battery is too hot!";
14 AE::log error => "Division by zero attempted.";
15 AE::log warn => "Couldn't delete the file.";
16 AE::log note => "Attempted to create config, but config already exists.";
17 AE::log info => "File soandso successfully deleted.";
18 AE::log debug => "the function returned 3";
11 AE::log trace => "going to call function abc"; 19 AE::log trace => "going to call function abc";
12 AE::log debug => "the function returned 3";
13 AE::log info => "file soandso successfully deleted";
14 AE::log note => "wanted to create config, but config was alraedy created";
15 AE::log warn => "couldn't delete the file";
16 AE::log error => "failed to retrieve data";
17 AE::log crit => "the battery temperature is too hot";
18 AE::log alert => "the battery died";
19 AE::log fatal => "no config found, cannot continue"; # never returns
20 20
21Log level overview: 21Log level overview:
22 22
23 LVL NAME SYSLOG PERL NOTE 23 LVL NAME SYSLOG PERL NOTE
24 1 fatal emerg exit system unusable, aborts program! 24 1 fatal emerg exit system unusable, aborts program!
33 33
34"Complex" uses (for speed sensitive code, e.g. trace/debug messages): 34"Complex" uses (for speed sensitive code, e.g. trace/debug messages):
35 35
36 use AnyEvent::Log; 36 use AnyEvent::Log;
37 37
38 my $tracer = AnyEvent::Log::logger trace => \$my $trace; 38 my $tracer = AnyEvent::Log::logger trace => \my $trace;
39 39
40 $tracer->("i am here") if $trace; 40 $tracer->("i am here") if $trace;
41 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace; 41 $tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
42 42
43Configuration (also look at the EXAMPLES section): 43Configuration (also look at the EXAMPLES section):
44 44
45 # set default logging level to suppress anything below "notice"
46 # i.e. enable logging at "notice" or above - the default is to
47 # to not log anything at all.
48 $AnyEvent::Log::FILTER->level ("notice");
49
45 # set logging for the current package to errors and higher only 50 # set logging for the current package to errors and higher only
46 AnyEvent::Log::ctx->level ("error"); 51 AnyEvent::Log::ctx->level ("error");
47 52
48 # set logging level to suppress anything below "notice" 53 # enable logging for the current package, regardless of global logging level
49 $AnyEvent::Log::FILTER->level ("notice"); 54 AnyEvent::Log::ctx->attach ($AnyEvent::Log::LOG);
55
56 # enable debug logging for module some::mod and enable logging by default
57 (AnyEvent::Log::ctx "some::mod")->level ("debug");
58 (AnyEvent::Log::ctx "some::mod")->attach ($AnyEvent::Log::LOG);
50 59
51 # send all critical and higher priority messages to syslog, 60 # send all critical and higher priority messages to syslog,
52 # regardless of (most) other settings 61 # regardless of (most) other settings
53 $AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx 62 $AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
54 level => "critical", 63 level => "critical",
61attempt to be "the" logging solution or even "a" logging solution for 70attempt to be "the" logging solution or even "a" logging solution for
62AnyEvent - AnyEvent simply creates logging messages internally, and this 71AnyEvent - AnyEvent simply creates logging messages internally, and this
63module more or less exposes the mechanism, with some extra spiff to allow 72module more or less exposes the mechanism, with some extra spiff to allow
64using it from other modules as well. 73using it from other modules as well.
65 74
66Remember that the default verbosity level is C<0> (C<off>), so nothing 75Remember that the default verbosity level is C<4> (C<error>), so only
67will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number 76errors and more important messages will be logged, unless you set
68before starting your program, or change the logging level at runtime with 77C<PERL_ANYEVENT_VERBOSE> to a higher number before starting your program
69something like: 78(C<AE_VERBOSE=5> is recommended during development), or change the logging
79level at runtime with something like:
70 80
71 use AnyEvent::Log; 81 use AnyEvent::Log;
72 $AnyEvent::Log::FILTER->level ("info"); 82 $AnyEvent::Log::FILTER->level ("info");
73 83
74The design goal behind this module was to keep it simple (and small), 84The design goal behind this module was to keep it simple (and small),
75but make it powerful enough to be potentially useful for any module, and 85but make it powerful enough to be potentially useful for any module,
76extensive enough for the most common tasks, such as logging to multiple 86and extensive enough for the most common tasks, such as logging to
77targets, or being able to log into a database. 87multiple targets, or being able to log into a database.
78 88
79The module is also usable before AnyEvent itself is initialised, in which 89The module is also usable before AnyEvent itself is initialised, in which
80case some of the functionality might be reduced. 90case some of the functionality might be reduced.
81 91
82The amount of documentation might indicate otherwise, but the runtime part 92The amount of documentation might indicate otherwise, but the runtime part
106is the "official" name, the second one the "syslog" name (if it differs) 116is the "official" name, the second one the "syslog" name (if it differs)
107and the third one the "perl" name, suggesting (only!) that you log C<die> 117and the third one the "perl" name, suggesting (only!) that you log C<die>
108messages at C<error> priority. The NOTE column tries to provide some 118messages at C<error> priority. The NOTE column tries to provide some
109rationale on how to chose a logging level. 119rationale on how to chose a logging level.
110 120
111As a rough guideline, levels 1..3 are primarily meant for users of 121As a rough guideline, levels 1..3 are primarily meant for users of the
112the program (admins, staff), and are the only logged to STDERR by 122program (admins, staff), and are the only ones logged to STDERR by
113default. Levels 4..6 are meant for users and developers alike, while 123default. Levels 4..6 are meant for users and developers alike, while
114levels 7..9 are usually meant for developers. 124levels 7..9 are usually meant for developers.
115 125
116You can normally only log a single message at highest priority level 126You can normally only log a message once at highest priority level (C<1>,
117(C<1>, C<fatal>), because logging a fatal message will also quit the 127C<fatal>), because logging a fatal message will also quit the program - so
118program - so use it sparingly :) 128use it sparingly :)
129
130For example, a program that finds an unknown switch on the commandline
131might well use a fatal logging level to tell users about it - the "system"
132in this case would be the program, or module.
119 133
120Some methods also offer some extra levels, such as C<0>, C<off>, C<none> 134Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
121or C<all> - these are only valid in the methods they are documented for. 135or C<all> - these are only valid for the methods that document them.
122 136
123=head1 LOGGING FUNCTIONS 137=head1 LOGGING FUNCTIONS
124 138
125These functions allow you to log messages. They always use the caller's 139The following functions allow you to log messages. They always use the
126package as a "logging context". Also, the main logging function C<log> is 140caller's package as a "logging context". Also, the main logging function,
127callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is 141C<log>, is aliased to C<AnyEvent::log> and C<AE::log> when the C<AnyEvent>
128loaded. 142module is loaded.
129 143
130=over 4 144=over 4
131 145
132=cut 146=cut
133 147
134package AnyEvent::Log; 148package AnyEvent::Log;
135 149
136use Carp (); 150use Carp ();
137use POSIX (); 151use POSIX ();
138 152
153# layout of a context
154# 0 1 2 3 4, 5
155# [$title, $level, %$slaves, &$logcb, &$fmtcb, $cap]
156
139use AnyEvent (); BEGIN { AnyEvent::common_sense } 157use AnyEvent (); BEGIN { AnyEvent::common_sense }
140#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log 158#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
141 159
142our $VERSION = $AnyEvent::VERSION; 160our $VERSION = $AnyEvent::VERSION;
143 161
144our ($COLLECT, $FILTER, $LOG); 162our ($COLLECT, $FILTER, $LOG);
145 163
146our ($now_int, $now_str1, $now_str2); 164our ($now_int, $now_str1, $now_str2);
147 165
148# Format Time, not public - yet? 166# Format Time, not public - yet?
149sub ft($) { 167sub format_time($) {
150 my $i = int $_[0]; 168 my $i = int $_[0];
151 my $f = sprintf "%06d", 1e6 * ($_[0] - $i); 169 my $f = sprintf "%06d", 1e6 * ($_[0] - $i);
152 170
153 ($now_int, $now_str1, $now_str2) = ($i, split /\x01/, POSIX::strftime "%Y-%m-%d %H:%M:%S.\x01 %z", localtime $i) 171 ($now_int, $now_str1, $now_str2) = ($i, split /\x01/, POSIX::strftime "%Y-%m-%d %H:%M:%S.\x01 %z", localtime $i)
154 if $now_int != $i; 172 if $now_int != $i;
187 205
188Last not least, C<$msg> might be a code reference, in which case it is 206Last not least, C<$msg> might be a code reference, in which case it is
189supposed to return the message. It will be called only then the message 207supposed to return the message. It will be called only then the message
190actually gets logged, which is useful if it is costly to create the 208actually gets logged, which is useful if it is costly to create the
191message in the first place. 209message in the first place.
210
211This function takes care of saving and restoring C<$!> and C<$@>, so you
212don't have to.
192 213
193Whether the given message will be logged depends on the maximum log level 214Whether the given message will be logged depends on the maximum log level
194and the caller's package. The return value can be used to ensure that 215and the caller's package. The return value can be used to ensure that
195messages or not "lost" - for example, when L<AnyEvent::Debug> detects a 216messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
196runtime error it tries to log it at C<die> level, but if that message is 217runtime error it tries to log it at C<die> level, but if that message is
250}; 271};
251 272
252our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace); 273our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
253 274
254# time, ctx, level, msg 275# time, ctx, level, msg
255sub _format($$$$) { 276sub default_format($$$$) {
256 my $ts = ft $_[0]; 277 my $ts = format_time $_[0];
257 my $ct = " "; 278 my $ct = " ";
258 279
259 my @res; 280 my @res;
260 281
261 for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) { 282 for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
277 ? $level+0 298 ? $level+0
278 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught"; 299 : $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
279 300
280 my $mask = 1 << $level; 301 my $mask = 1 << $level;
281 302
282 my ($success, %seen, @ctx, $now, $fmt); 303 my ($success, %seen, @ctx, $now, @fmt);
283 304
284 do 305 do
285 { 306 {
286 # skip if masked 307 # if !ref, then it's a level number
308 if (!ref $ctx) {
309 $level = $ctx;
287 if ($ctx->[1] & $mask && !$seen{$ctx+0}++) { 310 } elsif ($ctx->[1] & $mask and !$seen{$ctx+0}++) {
311 # logging/recursing into this context
312
313 # level cap
314 if ($ctx->[5] > $level) {
315 push @ctx, $level; # restore level when going up in tree
316 $level = $ctx->[5];
317 }
318
319 # log if log cb
288 if ($ctx->[3]) { 320 if ($ctx->[3]) {
289 # logging target found 321 # logging target found
322
323 local ($!, $@);
290 324
291 # now get raw message, unless we have it already 325 # now get raw message, unless we have it already
292 unless ($now) { 326 unless ($now) {
293 $format = $format->() if ref $format; 327 $format = $format->() if ref $format;
294 $format = sprintf $format, @args if @args; 328 $format = sprintf $format, @args if @args;
297 }; 331 };
298 332
299 # format msg 333 # format msg
300 my $str = $ctx->[4] 334 my $str = $ctx->[4]
301 ? $ctx->[4]($now, $_[0], $level, $format) 335 ? $ctx->[4]($now, $_[0], $level, $format)
302 : ($fmt ||= _format $now, $_[0], $level, $format); 336 : ($fmt[$level] ||= default_format $now, $_[0], $level, $format);
303 337
304 $success = 1; 338 $success = 1;
305 339
306 $ctx->[3]($str) 340 $ctx->[3]($str)
307 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate 341 or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
424time on each log message. This only makes a difference for event loops 458time on each log message. This only makes a difference for event loops
425that actually cache the time (such as L<EV> or L<AnyEvent::Loop>). 459that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
426 460
427This setting can be changed at any time by calling this function. 461This setting can be changed at any time by calling this function.
428 462
429Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been 463Since C<AnyEvent::Log> has to work even before L<AnyEvent> has been
430initialised, this switch will also decide whether to use C<CORE::time> or 464initialised, this switch will also decide whether to use C<CORE::time> or
431C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes 465C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
432available. 466available.
467
468=item AnyEvent::Log::format_time $timestamp
469
470Formats a timestamp as returned by C<< AnyEvent->now >> or C<<
471AnyEvent->time >> or many other functions in the same way as
472C<AnyEvent::Log> does.
473
474In your main program (as opposed to in your module) you can override
475the default timestamp display format by loading this module and then
476redefining this function.
477
478Most commonly, this function can be used in formatting callbacks.
479
480=item AnyEvent::Log::default_format $time, $ctx, $level, $msg
481
482Format a log message using the given timestamp, logging context, log level
483and log message.
484
485This is the formatting function used to format messages when no custom
486function is provided.
487
488In your main program (as opposed to in your module) you can override the
489default message format by loading this module and then redefining this
490function.
491
492=item AnyEvent::Log::fatal_exit()
493
494This is the function that is called after logging a C<fatal> log
495message. It must not return.
496
497The default implementation simply calls C<exit 1>.
498
499In your main program (as opposed to in your module) you can override
500the fatal exit function by loading this module and then redefining this
501function. Make sure you don't return.
433 502
434=back 503=back
435 504
436=head1 LOGGING CONTEXTS 505=head1 LOGGING CONTEXTS
437 506
461context, so it does not matter (much) if there are cycles or if the 530context, so it does not matter (much) if there are cycles or if the
462message can arrive at the same context via multiple paths. 531message can arrive at the same context via multiple paths.
463 532
464=head2 DEFAULTS 533=head2 DEFAULTS
465 534
466By default, all logging contexts have an full set of log levels ("all"), a 535By default, all logging contexts have a full set of log levels ("all"), a
467disabled logging callback and the default formatting callback. 536disabled logging callback and the default formatting callback.
468 537
469Package contexts have the package name as logging title by default. 538Package contexts have the package name as logging title by default.
470 539
471They have exactly one slave - the context of the "parent" package. The 540They have exactly one slave - the context of the "parent" package. The
525 594
526=item $ctx = AnyEvent::Log::ctx [$pkg] 595=item $ctx = AnyEvent::Log::ctx [$pkg]
527 596
528This function creates or returns a logging context (which is an object). 597This function creates or returns a logging context (which is an object).
529 598
530If a package name is given, then the context for that packlage is 599If a package name is given, then the context for that package is
531returned. If it is called without any arguments, then the context for the 600returned. If it is called without any arguments, then the context for the
532callers package is returned (i.e. the same context as a C<AE::log> call 601callers package is returned (i.e. the same context as a C<AE::log> call
533would use). 602would use).
534 603
535If C<undef> is given, then it creates a new anonymous context that is not 604If C<undef> is given, then it creates a new anonymous context that is not
611package AnyEvent::Log::COLLECT; 680package AnyEvent::Log::COLLECT;
612package AE::Log::COLLECT; 681package AE::Log::COLLECT;
613 682
614package AnyEvent::Log::Ctx; 683package AnyEvent::Log::Ctx;
615 684
616# 0 1 2 3 4
617# [$title, $level, %$slaves, &$logcb, &$fmtcb]
618
619=item $ctx = new AnyEvent::Log::Ctx methodname => param... 685=item $ctx = new AnyEvent::Log::Ctx methodname => param...
620 686
621This is a convenience constructor that makes it simpler to construct 687This is a convenience constructor that makes it simpler to construct
622anonymous logging contexts. 688anonymous logging contexts.
623 689
710 776
711=item $ctx->disable ($level[, $level...]) 777=item $ctx->disable ($level[, $level...])
712 778
713Disables logging for the given levels, leaving all others unchanged. 779Disables logging for the given levels, leaving all others unchanged.
714 780
781=item $ctx->cap ($level)
782
783Caps the maximum priority to the given level, for all messages logged
784to, or passing through, this context. That is, while this doesn't affect
785whether a message is logged or passed on, the maximum priority of messages
786will be limited to the specified level - messages with a higher priority
787will be set to the specified priority.
788
789Another way to view this is that C<< ->level >> filters out messages with
790a too low priority, while C<< ->cap >> modifies messages with a too high
791priority.
792
793This is useful when different log targets have different interpretations
794of priority. For example, for a specific command line program, a wrong
795command line switch might well result in a C<fatal> log message, while the
796same message, logged to syslog, is likely I<not> fatal to the system or
797syslog facility as a whole, but more likely a mere C<error>.
798
799This can be modeled by having a stderr logger that logs messages "as-is"
800and a syslog logger that logs messages with a level cap of, say, C<error>,
801or, for truly system-critical components, actually C<critical>.
802
715=cut 803=cut
716 804
717sub _lvl_lst { 805sub _lvl_lst {
718 map { 806 map {
719 $_ > 0 && $_ <= 9 ? $_+0 807 $_ > 0 && $_ <= 9 ? $_+0
720 : $_ eq "all" ? (1 .. 9) 808 : $_ eq "all" ? (1 .. 9)
721 : $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught" 809 : $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught"
722 } @_ 810 } @_
723} 811}
724 812
813sub _lvl {
814 $_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[-1]
815}
816
725our $NOP_CB = sub { 0 }; 817our $NOP_CB = sub { 0 };
726 818
727sub levels { 819sub levels {
728 my $ctx = shift; 820 my $ctx = shift;
729 $ctx->[1] = 0; 821 $ctx->[1] = 0;
732 AnyEvent::Log::_reassess; 824 AnyEvent::Log::_reassess;
733} 825}
734 826
735sub level { 827sub level {
736 my $ctx = shift; 828 my $ctx = shift;
737 my $lvl = $_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
738
739 $ctx->[1] = ((1 << $lvl) - 1) << 1; 829 $ctx->[1] = ((1 << &_lvl) - 1) << 1;
740 AnyEvent::Log::_reassess; 830 AnyEvent::Log::_reassess;
741} 831}
742 832
743sub enable { 833sub enable {
744 my $ctx = shift; 834 my $ctx = shift;
752 $ctx->[1] &= ~(1 << $_) 842 $ctx->[1] &= ~(1 << $_)
753 for &_lvl_lst; 843 for &_lvl_lst;
754 AnyEvent::Log::_reassess; 844 AnyEvent::Log::_reassess;
755} 845}
756 846
847sub cap {
848 my $ctx = shift;
849 $ctx->[5] = &_lvl;
850}
851
757=back 852=back
758 853
759=head3 SLAVE CONTEXTS 854=head3 SLAVE CONTEXTS
760 855
761The following methods attach and detach another logging context to a 856The following methods attach and detach another logging context to a
789sub attach { 884sub attach {
790 my $ctx = shift; 885 my $ctx = shift;
791 886
792 $ctx->[2]{$_+0} = $_ 887 $ctx->[2]{$_+0} = $_
793 for map { AnyEvent::Log::ctx $_ } @_; 888 for map { AnyEvent::Log::ctx $_ } @_;
889 AnyEvent::Log::_reassess;
794} 890}
795 891
796sub detach { 892sub detach {
797 my $ctx = shift; 893 my $ctx = shift;
798 894
799 delete $ctx->[2]{$_+0} 895 delete $ctx->[2]{$_+0}
800 for map { AnyEvent::Log::ctx $_ } @_; 896 for map { AnyEvent::Log::ctx $_ } @_;
897 AnyEvent::Log::_reassess;
801} 898}
802 899
803sub slaves { 900sub slaves {
804 undef $_[0][2]; 901 undef $_[0][2];
805 &attach; 902 &attach;
903 AnyEvent::Log::_reassess;
806} 904}
807 905
808=back 906=back
809 907
810=head3 LOG TARGETS 908=head3 LOG TARGETS
813the logging (which consists of formatting the message and printing it or 911the logging (which consists of formatting the message and printing it or
814whatever it wants to do with it). 912whatever it wants to do with it).
815 913
816=over 4 914=over 4
817 915
818=item $ctx->log_cb ($cb->($str) 916=item $ctx->log_cb ($cb->($str))
819 917
820Replaces the logging callback on the context (C<undef> disables the 918Replaces the logging callback on the context (C<undef> disables the
821logging callback). 919logging callback).
822 920
823The logging callback is responsible for handling formatted log messages 921The logging callback is responsible for handling formatted log messages
848 946
849Replaces the formatting callback on the context (C<undef> restores the 947Replaces the formatting callback on the context (C<undef> restores the
850default formatter). 948default formatter).
851 949
852The callback is passed the (possibly fractional) timestamp, the original 950The callback is passed the (possibly fractional) timestamp, the original
853logging context, the (numeric) logging level and the raw message string 951logging context (object, not title), the (numeric) logging level and
854and needs to return a formatted log message. In most cases this will be a 952the raw message string and needs to return a formatted log message. In
855string, but it could just as well be an array reference that just stores 953most cases this will be a string, but it could just as well be an array
856the values. 954reference that just stores the values.
857 955
858If, for some reason, you want to use C<caller> to find out more baout the 956If, for some reason, you want to use C<caller> to find out more about the
859logger then you should walk up the call stack until you are no longer 957logger then you should walk up the call stack until you are no longer
860inside the C<AnyEvent::Log> package. 958inside the C<AnyEvent::Log> package.
861 959
960To implement your own logging callback, you might find the
961C<AnyEvent::Log::format_time> and C<AnyEvent::Log::default_format>
962functions useful.
963
964Example: format the message just as AnyEvent::Log would, by letting
965AnyEvent::Log do the work. This is a good basis to design a formatting
966callback that only changes minor aspects of the formatting.
967
968 $ctx->fmt_cb (sub {
969 my ($time, $ctx, $lvl, $msg) = @_;
970
971 AnyEvent::Log::default_format $time, $ctx, $lvl, $msg
972 });
973
862Example: format just the raw message, with numeric log level in angle 974Example: format just the raw message, with numeric log level in angle
863brackets. 975brackets.
864 976
865 $ctx->fmt_cb (sub { 977 $ctx->fmt_cb (sub {
866 my ($time, $ctx, $lvl, $msg) = @_; 978 my ($time, $ctx, $lvl, $msg) = @_;
867 979
868 "<$lvl>$msg\n" 980 "<$lvl>$msg\n"
869 }); 981 });
870 982
871Example: return an array reference with just the log values, and use 983Example: return an array reference with just the log values, and use
872C<PApp::SQL::sql_exec> to store the emssage in a database. 984C<PApp::SQL::sql_exec> to store the message in a database.
873 985
874 $ctx->fmt_cb (sub { \@_ }); 986 $ctx->fmt_cb (sub { \@_ });
875 $ctx->log_cb (sub { 987 $ctx->log_cb (sub {
876 my ($msg) = @_; 988 my ($msg) = @_;
877 989
889Sets the C<log_cb> to simply use C<CORE::warn> to report any messages 1001Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
890(usually this logs to STDERR). 1002(usually this logs to STDERR).
891 1003
892=item $ctx->log_to_file ($path) 1004=item $ctx->log_to_file ($path)
893 1005
894Sets the C<log_cb> to log to a file (by appending), unbuffered. 1006Sets the C<log_cb> to log to a file (by appending), unbuffered. The
1007function might return before the log file has been opened or created.
895 1008
896=item $ctx->log_to_path ($path) 1009=item $ctx->log_to_path ($path)
897 1010
898Same as C<< ->log_to_file >>, but opens the file for each message. This 1011Same as C<< ->log_to_file >>, but opens the file for each message. This
899is much slower, but allows you to change/move/rename/delete the file at 1012is much slower, but allows you to change/move/rename/delete the file at
934 warn shift; 1047 warn shift;
935 0 1048 0
936 }); 1049 });
937} 1050}
938 1051
1052# this function is a good example of why threads are a must,
1053# simply for priority inversion.
1054sub _log_to_disk {
1055 # eval'uating this at runtime saves 220kb rss - perl has become
1056 # an insane memory waster.
1057 eval q{ # poor man's autoloading {}
1058 sub _log_to_disk {
1059 my ($ctx, $path, $keepopen) = @_;
1060
1061 my $fh;
1062 my @queue;
1063 my $delay;
1064 my $disable;
1065
1066 use AnyEvent::IO ();
1067
1068 my $kick = sub {
1069 undef $delay;
1070 return unless @queue;
1071 $delay = 1;
1072
1073 # we pass $kick to $kick, so $kick itself doesn't keep a reference to $kick.
1074 my $kick = shift;
1075
1076 # write one or more messages
1077 my $write = sub {
1078 # we write as many messages as have been queued
1079 my $data = join "", @queue;
1080 @queue = ();
1081
1082 AnyEvent::IO::aio_write $fh, $data, sub {
1083 $disable = 1;
1084 @_
1085 ? ($_[0] == length $data or AE::log 4 => "unable to write to logfile '$path': short write")
1086 : AE::log 4 => "unable to write to logfile '$path': $!";
1087 undef $disable;
1088
1089 if ($keepopen) {
1090 $kick->($kick);
1091 } else {
1092 AnyEvent::IO::aio_close ($fh, sub {
1093 undef $fh;
1094 $kick->($kick);
1095 });
1096 }
1097 };
1098 };
1099
1100 if ($fh) {
1101 $write->();
1102 } else {
1103 AnyEvent::IO::aio_open
1104 $path,
1105 AnyEvent::IO::O_CREAT | AnyEvent::IO::O_WRONLY | AnyEvent::IO::O_APPEND,
1106 0666,
1107 sub {
1108 $fh = shift
1109 or do {
1110 $disable = 1;
1111 AE::log 4 => "unable to open logfile '$path': $!";
1112 undef $disable;
1113 return;
1114 };
1115
1116 $write->();
1117 }
1118 ;
1119 }
1120 };
1121
1122 $ctx->log_cb (sub {
1123 return if $disable;
1124 push @queue, shift;
1125 $kick->($kick) unless $delay;
1126 0
1127 });
1128
1129 $kick->($kick) if $keepopen; # initial open
1130 };
1131 };
1132 die if $@;
1133 &_log_to_disk
1134}
1135
939sub log_to_file { 1136sub log_to_file {
940 my ($ctx, $path) = @_; 1137 my ($ctx, $path) = @_;
941 1138
942 open my $fh, ">>", $path 1139 _log_to_disk $ctx, $path, 1;
943 or die "$path: $!";
944
945 $ctx->log_cb (sub {
946 syswrite $fh, shift;
947 0
948 });
949} 1140}
950 1141
951sub log_to_path { 1142sub log_to_path {
952 my ($ctx, $path) = @_; 1143 my ($ctx, $path) = @_;
953 1144
954 $ctx->log_cb (sub { 1145 _log_to_disk $ctx, $path, 0;
955 open my $fh, ">>", $path
956 or die "$path: $!";
957
958 syswrite $fh, shift;
959 0
960 });
961} 1146}
962 1147
963sub log_to_syslog { 1148sub log_to_syslog {
964 my ($ctx, $facility) = @_; 1149 my ($ctx, $facility) = @_;
965 1150
994=over 4 1179=over 4
995 1180
996=item $ctx->log ($level, $msg[, @params]) 1181=item $ctx->log ($level, $msg[, @params])
997 1182
998Same as C<AnyEvent::Log::log>, but uses the given context as log context. 1183Same as C<AnyEvent::Log::log>, but uses the given context as log context.
1184
1185Example: log a message in the context of another package.
1186
1187 (AnyEvent::Log::ctx "Other::Package")->log (warn => "heely bo");
999 1188
1000=item $logger = $ctx->logger ($level[, \$enabled]) 1189=item $logger = $ctx->logger ($level[, \$enabled])
1001 1190
1002Same as C<AnyEvent::Log::logger>, but uses the given context as log 1191Same as C<AnyEvent::Log::logger>, but uses the given context as log
1003context. 1192context.
1051 1240
1052Context names starting with a C<%> are anonymous contexts created when the 1241Context names starting with a C<%> are anonymous contexts created when the
1053name is first mentioned. The difference to package contexts is that by 1242name is first mentioned. The difference to package contexts is that by
1054default they have no attached slaves. 1243default they have no attached slaves.
1055 1244
1245This makes it possible to create new log contexts that can be refered to
1246multiple times by name within the same log specification.
1247
1056=item a perl package name 1248=item a perl package name
1057 1249
1058Any other string references the logging context associated with the given 1250Any other string references the logging context associated with the given
1059Perl C<package>. In the unlikely case where you want to specify a package 1251Perl C<package>. In the unlikely case where you want to specify a package
1060context that matches on of the other context name forms, you can add a 1252context that matches on of the other context name forms, you can add a
1091=item C<nolog> 1283=item C<nolog>
1092 1284
1093Configures the context to not log anything by itself, which is the 1285Configures the context to not log anything by itself, which is the
1094default. Same as C<< $ctx->log_cb (undef) >>. 1286default. Same as C<< $ctx->log_cb (undef) >>.
1095 1287
1288=item C<cap=>I<level>
1289
1290Caps logging messages entering this context at the given level, i.e.
1291reduces the priority of messages with higher priority than this level. The
1292default is C<0> (or C<off>), meaning the priority will not be touched.
1293
1096=item C<0> or C<off> 1294=item C<0> or C<off>
1097 1295
1098Sets the logging level of the context ot C<0>, i.e. all messages will be 1296Sets the logging level of the context to C<0>, i.e. all messages will be
1099filtered out. 1297filtered out.
1100 1298
1101=item C<all> 1299=item C<all>
1102 1300
1103Enables all logging levels, i.e. filtering will effectively be switched 1301Enables all logging levels, i.e. filtering will effectively be switched
1145 1343
1146Attaches the named context as slave to the context. 1344Attaches the named context as slave to the context.
1147 1345
1148=item C<+> 1346=item C<+>
1149 1347
1150A line C<+> detaches all contexts, i.e. clears the slave list from the 1348A lone C<+> detaches all contexts, i.e. clears the slave list from the
1151context. Anonymous (C<%name>) contexts have no attached slaves by default, 1349context. Anonymous (C<%name>) contexts have no attached slaves by default,
1152but package contexts have the parent context as slave by default. 1350but package contexts have the parent context as slave by default.
1153 1351
1154Example: log messages from My::Module to a file, do not send them to the 1352Example: log messages from My::Module to a file, do not send them to the
1155default log collector. 1353default log collector.
1186 1384
1187 my $pkg = sub { 1385 my $pkg = sub {
1188 $_[0] eq "log" ? $LOG 1386 $_[0] eq "log" ? $LOG
1189 : $_[0] eq "filter" ? $FILTER 1387 : $_[0] eq "filter" ? $FILTER
1190 : $_[0] eq "collect" ? $COLLECT 1388 : $_[0] eq "collect" ? $COLLECT
1191 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= ctx undef) 1389 : $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= do { my $ctx = ctx undef; $ctx->[0] = $_[0]; $ctx })
1192 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/ 1390 : $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
1193 : die # never reached? 1391 : die # never reached?
1194 }; 1392 };
1195 1393
1196 /\G[[:space:]]+/gc; # skip initial whitespace 1394 /\G[[:space:]]+/gc; # skip initial whitespace
1202 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) { 1400 while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
1203 for ("$1") { 1401 for ("$1") {
1204 if ($_ eq "stderr" ) { $ctx->log_to_warn; 1402 if ($_ eq "stderr" ) { $ctx->log_to_warn;
1205 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1"); 1403 } elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
1206 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1"); 1404 } elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
1207 } elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ($1); 1405 } elsif (/^syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ("$1");
1208 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef); 1406 } elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
1407 } elsif (/^cap=(.+)/ ) { $ctx->cap ("$1");
1209 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1")); 1408 } elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
1210 } elsif ($_ eq "+" ) { $ctx->slaves; 1409 } elsif ($_ eq "+" ) { $ctx->slaves;
1211 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0); 1410 } elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
1212 } elsif ($_ eq "all" ) { $ctx->level ("all"); 1411 } elsif ($_ eq "all" ) { $ctx->level ("all");
1213 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level"; 1412 } elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
1230 if (/\G(.+)/g) { 1429 if (/\G(.+)/g) {
1231 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n"; 1430 die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
1232 } 1431 }
1233} 1432}
1234 1433
12351;
1236
1237=head1 EXAMPLES 1434=head1 EXAMPLES
1238 1435
1239This section shows some common configurations, both as code, and as 1436This section shows some common configurations, both as code, and as
1240C<PERL_ANYEVENT_LOG> string. 1437C<PERL_ANYEVENT_LOG> string.
1241 1438
1281 1478
1282 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger 1479 PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
1283 1480
1284In both cases, messages are still written to STDERR. 1481In both cases, messages are still written to STDERR.
1285 1482
1483=item Additionally log all messages with C<warn> and higher priority to
1484C<syslog>, but cap at C<error>.
1485
1486This logs all messages to the default log target, but also logs messages
1487with priority C<warn> or higher (and not filtered otherwise) to syslog
1488facility C<user>. Messages with priority higher than C<error> will be
1489logged with level C<error>.
1490
1491 $AnyEvent::Log::LOG->attach (
1492 new AnyEvent::Log::Ctx
1493 level => "warn",
1494 cap => "error",
1495 syslog => "user",
1496 );
1497
1498 PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
1499
1286=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s). 1500=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
1287 1501
1288Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug> 1502Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
1289context - this simply circumvents the global filtering for trace messages. 1503context - this simply circumvents the global filtering for trace messages.
1290 1504
1297assumes the log level for AnyEvent::Debug hasn't been changed from the 1511assumes the log level for AnyEvent::Debug hasn't been changed from the
1298default. 1512default.
1299 1513
1300=back 1514=back
1301 1515
1516=head1 ASYNCHRONOUS DISK I/O
1517
1518This module uses L<AnyEvent::IO> to actually write log messages (in
1519C<log_to_file> and C<log_to_path>), so it doesn't block your program when
1520the disk is busy and a non-blocking L<AnyEvent::IO> backend is available.
1521
1302=head1 AUTHOR 1522=head1 AUTHOR
1303 1523
1304 Marc Lehmann <schmorp@schmorp.de> 1524 Marc Lehmann <schmorp@schmorp.de>
1305 http://home.schmorp.de/ 1525 http://anyevent.schmorp.de
1306 1526
1307=cut 1527=cut
1308 1528
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