[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent/Log.pm

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs.
Revision 1.44 by root, Mon Sep 26 11:32:19 2011 UTC

…		…
2		2
3	AnyEvent::Log - simple logging "framework"	3	AnyEvent::Log - simple logging "framework"
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
		7	Simple uses:
		8
		9	use AnyEvent;
		10
		11	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
		21	Log level overview:
		22
		23	LVL NAME SYSLOG PERL NOTE
		24	1 fatal emerg exit system unusable, aborts program!
		25	2 alert failure in primary system
		26	3 critical crit failure in backup system
		27	4 error err die non-urgent program errors, a bug
		28	5 warn warning possible problem, not necessarily error
		29	6 note notice unusual conditions
		30	7 info normal messages, no action required
		31	8 debug debugging messages for development
		32	9 trace copious tracing output
		33
		34	"Complex" uses (for speed sensitive code, e.g. trace/debug messages):
		35
7	use AnyEvent::Log;	36	use AnyEvent::Log;
		37
		38	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
		39
		40	$tracer->("i am here") if $trace;
		41	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
		42
		43	Configuration (also look at the EXAMPLES section):
		44
		45	# set logging for the current package to errors and higher only
		46	AnyEvent::Log::ctx->level ("error");
		47
		48	# set logging level to suppress anything below "notice"
		49	$AnyEvent::Log::FILTER->level ("notice");
		50
		51	# send all critical and higher priority messages to syslog,
		52	# regardless of (most) other settings
		53	$AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
		54	level => "critical",
		55	log_to_syslog => "user",
		56	);
8		57
9	=head1 DESCRIPTION	58	=head1 DESCRIPTION
10		59
11	This module implements a relatively simple "logging framework". It doesn't	60	This module implements a relatively simple "logging framework". It doesn't
12	attempt to be "the" logging solution or even "a" logging solution for	61	attempt to be "the" logging solution or even "a" logging solution for
13	AnyEvent - AnyEvent simply creates logging messages internally, and this	62	AnyEvent - AnyEvent simply creates logging messages internally, and this
14	module more or less exposes the mechanism, with some extra spiff to allow	63	module more or less exposes the mechanism, with some extra spiff to allow
15	using it from other modules as well.	64	using it from other modules as well.
16		65
17	Remember that the default verbosity level is C<0>, so nothing	66	Remember that the default verbosity level is C<0> (C<off>), so nothing
18	will be logged, ever, unless you set C<$Anyvent::VERBOSE> or	67	will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
19	C<PERL_ANYEVENT_VERBOSE> to a higher number.	68	before starting your program, or change the logging level at runtime with
		69	something like:
20		70
21	Possible future extensions are to allow custom log targets (where the	71	use AnyEvent::Log;
22	level is an object), log filtering based on package, formatting, aliasing	72	$AnyEvent::Log::FILTER->level ("info");
23	or package groups.
24		73
		74	The design goal behind this module was to keep it simple (and small),
		75	but make it powerful enough to be potentially useful for any module, and
		76	extensive enough for the most common tasks, such as logging to multiple
		77	targets, or being able to log into a database.
		78
		79	The module is also usable before AnyEvent itself is initialised, in which
		80	case some of the functionality might be reduced.
		81
		82	The amount of documentation might indicate otherwise, but the runtime part
		83	of the module is still just below 300 lines of code.
		84
		85	=head1 LOGGING LEVELS
		86
		87	Logging levels in this module range from C<1> (highest priority) to C<9>
		88	(lowest priority). Note that the lowest numerical value is the highest
		89	priority, so when this document says "higher priority" it means "lower
		90	numerical value".
		91
		92	Instead of specifying levels by name you can also specify them by aliases:
		93
		94	LVL NAME SYSLOG PERL NOTE
		95	1 fatal emerg exit system unusable, aborts program!
		96	2 alert failure in primary system
		97	3 critical crit failure in backup system
		98	4 error err die non-urgent program errors, a bug
		99	5 warn warning possible problem, not necessarily error
		100	6 note notice unusual conditions
		101	7 info normal messages, no action required
		102	8 debug debugging messages for development
		103	9 trace copious tracing output
		104
		105	As you can see, some logging levels have multiple aliases - the first one
		106	is the "official" name, the second one the "syslog" name (if it differs)
		107	and the third one the "perl" name, suggesting (only!) that you log C<die>
		108	messages at C<error> priority. The NOTE column tries to provide some
		109	rationale on how to chose a logging level.
		110
		111	As a rough guideline, levels 1..3 are primarily meant for users of
		112	the program (admins, staff), and are the only logged to STDERR by
		113	default. Levels 4..6 are meant for users and developers alike, while
		114	levels 7..9 are usually meant for developers.
		115
		116	You can normally only log a single message at highest priority level
		117	(C<1>, C<fatal>), because logging a fatal message will also quit the
		118	program - so use it sparingly :)
		119
		120	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		121	or C<all> - these are only valid in the methods they are documented for.
		122
25	=head1 LOG FUNCTIONS	123	=head1 LOGGING FUNCTIONS
26		124
27	These functions allow you to log messages. They always use the caller's	125	These functions allow you to log messages. They always use the caller's
28	package as a "logging module/source". Also, The main logging function is	126	package as a "logging context". Also, the main logging function C<log> is
29	easily available as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent>	127	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
30	module is loaded.	128	loaded.
31		129
32	=over 4	130	=over 4
33		131
34	=cut	132	=cut
35		133
…		…
37		135
38	use Carp ();	136	use Carp ();
39	use POSIX ();	137	use POSIX ();
40		138
41	use AnyEvent (); BEGIN { AnyEvent::common_sense }	139	use AnyEvent (); BEGIN { AnyEvent::common_sense }
42	use AnyEvent::Util ();	140	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
		141
		142	our $VERSION = $AnyEvent::VERSION;
		143
		144	our ($COLLECT, $FILTER, $LOG);
43		145
44	our ($now_int, $now_str1, $now_str2);	146	our ($now_int, $now_str1, $now_str2);
45		147
46	# Format Time, not public - yet?	148	# Format Time, not public - yet?
47	sub ft($) {	149	sub ft($) {
…		…
52	if $now_int != $i;	154	if $now_int != $i;
53		155
54	"$now_str1$f$now_str2"	156	"$now_str1$f$now_str2"
55	}	157	}
56		158
57	our %CFG; #TODO	159	our %CTX; # all package contexts
		160
		161	# creates a default package context object for the given package
		162	sub _pkg_ctx($) {
		163	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
		164
		165	# link "parent" package
		166	my $parent = $_[0] =~ /^(.+)::/
		167	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		168	: $COLLECT;
		169
		170	$ctx->[2]{$parent+0} = $parent;
		171
		172	$ctx
		173	}
58		174
59	=item AnyEvent::Log::log $level, $msg[, @args]	175	=item AnyEvent::Log::log $level, $msg[, @args]
60		176
61	Requests logging of the given C<$msg> with the given log level (1..9).	177	Requests logging of the given C<$msg> with the given log level, and
62	You can also use the following strings as log level: C<fatal> (1),	178	returns true if the message was logged I<somewhere>.
63	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
64	C<info> (7), C<debug> (8), C<trace> (9).
65		179
66	For C<fatal> log levels, the program will abort.	180	For loglevel C<fatal>, the program will abort.
67		181
68	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	182	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
69	C<$msg> is interpreted as an sprintf format string.	183	C<$msg> is interpreted as an sprintf format string.
70		184
71	The C<$msg> should not end with C<\n>, but may if that is convenient for	185	The C<$msg> should not end with C<\n>, but may if that is convenient for
…		…
75	supposed to return the message. It will be called only then the message	189	supposed to return the message. It will be called only then the message
76	actually gets logged, which is useful if it is costly to create the	190	actually gets logged, which is useful if it is costly to create the
77	message in the first place.	191	message in the first place.
78		192
79	Whether the given message will be logged depends on the maximum log level	193	Whether the given message will be logged depends on the maximum log level
80	and the caller's package.	194	and the caller's package. The return value can be used to ensure that
		195	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		196	runtime error it tries to log it at C<die> level, but if that message is
		197	lost it simply uses warn.
81		198
82	Note that you can (and should) call this function as C<AnyEvent::log> or	199	Note that you can (and should) call this function as C<AnyEvent::log> or
83	C<AE::log>, without C<use>-ing this module if possible, as those functions	200	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
84	will laod the logging module on demand only.	201	need any additional functionality), as those functions will load the
		202	logging module on demand only. They are also much shorter to write.
		203
		204	Also, if you optionally generate a lot of debug messages (such as when
		205	tracing some code), you should look into using a logger callback and a
		206	boolean enabler (see C<logger>, below).
85		207
86	Example: log something at error level.	208	Example: log something at error level.
87		209
88	AE::log error => "something";	210	AE::log error => "something";
89		211
…		…
97		219
98	=cut	220	=cut
99		221
100	# also allow syslog equivalent names	222	# also allow syslog equivalent names
101	our %STR2LEVEL = (	223	our %STR2LEVEL = (
102	fatal => 1, emerg => 1,	224	fatal => 1, emerg => 1, exit => 1,
103	alert => 2,	225	alert => 2,
104	critical => 3, crit => 3,	226	critical => 3, crit => 3,
105	error => 4, err => 4,	227	error => 4, err => 4, die => 4,
106	warn => 5, warning => 5,	228	warn => 5, warning => 5,
107	note => 6, notice => 6,	229	note => 6, notice => 6,
108	info => 7,	230	info => 7,
109	debug => 8,	231	debug => 8,
110	trace => 9,	232	trace => 9,
111	);	233	);
112		234
		235	our $TIME_EXACT;
		236
		237	sub exact_time($) {
		238	$TIME_EXACT = shift;
		239	*_ts = $AnyEvent::MODEL
		240	? $TIME_EXACT ? \&AE::now : \&AE::time
		241	: sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
		242	}
		243
		244	BEGIN {
		245	exact_time 0;
		246	}
		247
		248	AnyEvent::post_detect {
		249	exact_time $TIME_EXACT;
		250	};
		251
113	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	252	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
114		253
		254	# time, ctx, level, msg
		255	sub _format($$$$) {
		256	my $ts = ft $_[0];
		257	my $ct = " ";
		258
		259	my @res;
		260
		261	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		262	push @res, "$ts$ct$_\n";
		263	$ct = " + ";
		264	}
		265
		266	join "", @res
		267	}
		268
		269	sub fatal_exit() {
		270	exit 1;
		271	}
		272
115	sub _log {	273	sub _log {
116	my ($pkg, $targ, $msg, @args) = @_;	274	my ($ctx, $level, $format, @args) = @_;
117		275
118	my $level = ref $targ ? die "Can't use reference as logging level (yet)"	276	$level = $level > 0 && $level <= 9
119	: $targ > 0 && $targ <= 9 ? $targ+0	277	? $level+0
120	: $STR2LEVEL{$targ} \|\| Carp::croak "$targ: not a valid logging level, caught";	278	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
121		279
122	return if $level > $AnyEvent::VERBOSE;	280	my $mask = 1 << $level;
123		281
124	$msg = $msg->() if ref $msg;	282	my ($success, %seen, @ctx, $now, $fmt);
125	$msg = sprintf $msg, @args if @args;
126	$msg =~ s/\n$//;
127		283
128	# now we have a message, log it	284	do
129	#TODO: could do LOTS of stuff here, and should, at least in some later version	285	{
		286	# skip if masked
		287	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		288	if ($ctx->[3]) {
		289	# logging target found
130		290
131	$msg = sprintf "%5s %s: %s", $LEVEL2STR[$level], $pkg, $msg;	291	# now get raw message, unless we have it already
132	my $pfx = ft AE::now;	292	unless ($now) {
		293	$format = $format->() if ref $format;
		294	$format = sprintf $format, @args if @args;
		295	$format =~ s/\n$//;
		296	$now = _ts;
		297	};
133		298
134	for (split /\n/, $msg) {	299	# format msg
135	printf STDERR "$pfx $_\n";	300	my $str = $ctx->[4]
136	$pfx = "\t";	301	? $ctx->[4]($now, $_[0], $level, $format)
137	}	302	: ($fmt \|\|= _format $now, $_[0], $level, $format);
138		303
		304	$success = 1;
		305
		306	$ctx->[3]($str)
		307	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		308	} else {
		309	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		310	}
		311	}
		312	}
		313	while $ctx = pop @ctx;
		314
139	exit 1 if $level <= 1;	315	fatal_exit if $level <= 1;
		316
		317	$success
140	}	318	}
141		319
142	sub log($$;@) {	320	sub log($$;@) {
143	_log +(caller)[0], @_;	321	_log
		322	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		323	@_;
144	}	324	}
145
146	AnyEvent::log = AE::log = \&log;
147		325
148	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	326	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
149		327
150	Creates a code reference that, when called, acts as if the	328	Creates a code reference that, when called, acts as if the
151	C<AnyEvent::Log::log> function was called at this point with the givne	329	C<AnyEvent::Log::log> function was called at this point with the given
152	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	330	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
153	the C<AnyEvent::Log::log> function:	331	the C<AnyEvent::Log::log> function:
154		332
155	my $debug_log = AnyEvent::Log::logger "debug";	333	my $debug_log = AnyEvent::Log::logger "debug";
156		334
…		…
181	# and later in your program	359	# and later in your program
182	$debug_log->("yo, stuff here") if $debug;	360	$debug_log->("yo, stuff here") if $debug;
183		361
184	$debug and $debug_log->("123");	362	$debug and $debug_log->("123");
185		363
186	Note: currently the enabled var is always true - that will be fixed in a
187	future version :)
188
189	=cut	364	=cut
190		365
191	our %LOGGER;	366	our %LOGGER;
192		367
193	# re-assess logging status for all loggers	368	# re-assess logging status for all loggers
194	sub _reassess {	369	sub _reassess {
		370	local $SIG{__DIE__};
		371	my $die = sub { die };
		372
195	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	373	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
196	my ($pkg, $level, $renabled) = @$_;	374	my ($ctx, $level, $renabled) = @$_;
197		375
198	# to detetc whether a message would be logged, we # actually	376	# to detect whether a message would be logged, we actually
199	# try to log one and die. this isn't # fast, but we can be	377	# try to log one and die. this isn't fast, but we can be
200	# sure that the logging decision is correct :)	378	# sure that the logging decision is correct :)
201		379
202	$$renabled = !eval {	380	$$renabled = !eval {
203	local $SIG{__DIE__};
204
205	_log $pkg, $level, sub { die };	381	_log $ctx, $level, $die;
206		382
207	1	383	1
208	};	384	};
209
210	$$renabled = 1; # TODO
211	}	385	}
212	}	386	}
213		387
214	sub logger($;$) {	388	sub _logger {
215	my ($level, $renabled) = @_;	389	my ($ctx, $level, $renabled) = @_;
216
217	$renabled \|\|= \my $enabled;
218	my $pkg = (caller)[0];
219		390
220	$$renabled = 1;	391	$$renabled = 1;
221		392
222	my $logger = [$pkg, $level, $renabled];	393	my $logger = [$ctx, $level, $renabled];
223		394
224	$LOGGER{$logger+0} = $logger;	395	$LOGGER{$logger+0} = $logger;
225		396
226	_reassess $logger+0;	397	_reassess $logger+0;
227		398
		399	require AnyEvent::Util unless $AnyEvent::Util::VERSION;
228	my $guard = AnyEvent::Util::guard {	400	my $guard = AnyEvent::Util::guard (sub {
229	# "clean up"	401	# "clean up"
230	delete $LOGGER{$logger+0};	402	delete $LOGGER{$logger+0};
231	};	403	});
232		404
233	sub {	405	sub {
234	$guard if 0; # keep guard alive, but don't cause runtime overhead	406	$guard if 0; # keep guard alive, but don't cause runtime overhead
235		407
236	_log $pkg, $level, @_	408	_log $ctx, $level, @_
237	if $$renabled;	409	if $$renabled;
238	}	410	}
239	}	411	}
240		412
241	#TODO	413	sub logger($;$) {
		414	_logger
		415	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		416	@_
		417	}
		418
		419	=item AnyEvent::Log::exact_time $on
		420
		421	By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
		422	eventloop time, for the log timestamps. After calling this function with a
		423	true value it will instead resort to C<AE::time>, i.e. fetch the current
		424	time on each log message. This only makes a difference for event loops
		425	that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
		426
		427	This setting can be changed at any time by calling this function.
		428
		429	Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
		430	initialised, this switch will also decide whether to use C<CORE::time> or
		431	C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
		432	available.
242		433
243	=back	434	=back
244		435
245	=head1 CONFIGURATION FUNCTIONALITY	436	=head1 LOGGING CONTEXTS
246		437
247	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	438	This module associates every log message with a so-called I<logging
		439	context>, based on the package of the caller. Every perl package has its
		440	own logging context.
		441
		442	A logging context has three major responsibilities: filtering, logging and
		443	propagating the message.
		444
		445	For the first purpose, filtering, each context has a set of logging
		446	levels, called the log level mask. Messages not in the set will be ignored
		447	by this context (masked).
		448
		449	For logging, the context stores a formatting callback (which takes the
		450	timestamp, context, level and string message and formats it in the way
		451	it should be logged) and a logging callback (which is responsible for
		452	actually logging the formatted message and telling C<AnyEvent::Log>
		453	whether it has consumed the message, or whether it should be propagated).
		454
		455	For propagation, a context can have any number of attached I<slave
		456	contexts>. Any message that is neither masked by the logging mask nor
		457	masked by the logging callback returning true will be passed to all slave
		458	contexts.
		459
		460	Each call to a logging function will log the message at most once per
		461	context, so it does not matter (much) if there are cycles or if the
		462	message can arrive at the same context via multiple paths.
		463
		464	=head2 DEFAULTS
		465
		466	By default, all logging contexts have an full set of log levels ("all"), a
		467	disabled logging callback and the default formatting callback.
		468
		469	Package contexts have the package name as logging title by default.
		470
		471	They have exactly one slave - the context of the "parent" package. The
		472	parent package is simply defined to be the package name without the last
		473	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		474	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		475	exception of the rule - just like the "parent" of any single-component
		476	package name in Perl is C<main>, the default slave of any top-level
		477	package context is C<$AnyEvent::Log::COLLECT>.
		478
		479	Since perl packages form only an approximate hierarchy, this slave
		480	context can of course be removed.
		481
		482	All other (anonymous) contexts have no slaves and an empty title by
		483	default.
		484
		485	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
		486	context that simply logs everything via C<warn>, without propagating
		487	anything anywhere by default. The purpose of this context is to provide
		488	a convenient place to override the global logging target or to attach
		489	additional log targets. It's not meant for filtering.
		490
		491	It then creates the C<$AnyEvent::Log::FILTER> context whose
		492	purpose is to suppress all messages with priority higher
		493	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		494	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		495	is to simply provide filtering according to some global log level.
		496
		497	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		498	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		499	leaves it at default config. Its purpose is simply to collect all log
		500	messages system-wide.
		501
		502	The hierarchy is then:
		503
		504	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		505
		506	The effect of all this is that log messages, by default, wander up to the
		507	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		508	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		509	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		510	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
		511
		512	This makes it easy to set a global logging level (by modifying $FILTER),
		513	but still allow other contexts to send, for example, their debug and trace
		514	messages to the $LOG target despite the global logging level, or to attach
		515	additional log targets that log messages, regardless of the global logging
		516	level.
		517
		518	It also makes it easy to modify the default warn-logger ($LOG) to
		519	something that logs to a file, or to attach additional logging targets
		520	(such as loggign to a file) by attaching it to $FILTER.
		521
		522	=head2 CREATING/FINDING/DESTROYING CONTEXTS
248		523
249	=over 4	524	=over 4
250		525
		526	=item $ctx = AnyEvent::Log::ctx [$pkg]
		527
		528	This function creates or returns a logging context (which is an object).
		529
		530	If a package name is given, then the context for that packlage is
		531	returned. If it is called without any arguments, then the context for the
		532	callers package is returned (i.e. the same context as a C<AE::log> call
		533	would use).
		534
		535	If C<undef> is given, then it creates a new anonymous context that is not
		536	tied to any package and is destroyed when no longer referenced.
		537
251	=cut	538	=cut
252		539
		540	sub ctx(;$) {
		541	my $pkg = @_ ? shift : (caller)[0];
		542
		543	ref $pkg
		544	? $pkg
		545	: defined $pkg
		546	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
		547	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
		548	}
		549
		550	=item AnyEvent::Log::reset
		551
		552	Resets all package contexts and recreates the default hierarchy if
		553	necessary, i.e. resets the logging subsystem to defaults, as much as
		554	possible. This process keeps references to contexts held by other parts of
		555	the program intact.
		556
		557	This can be used to implement config-file (re-)loading: before loading a
		558	configuration, reset all contexts.
		559
		560	=cut
		561
		562	our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
		563	$AnyEvent::VERBOSE = 9;
		564
		565	sub reset {
		566	# hard to kill complex data structures
		567	# we "recreate" all package loggers and reset the hierarchy
		568	while (my ($k, $v) = each %CTX) {
		569	@$v = ($k, (1 << 10) - 1 - 1, { });
		570
		571	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
		572	}
		573
		574	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		575	for $LOG, $FILTER, $COLLECT;
		576
		577	#$LOG->slaves;
		578	$LOG->title ('$AnyEvent::Log::LOG');
		579	$LOG->log_to_warn;
		580
		581	$FILTER->slaves ($LOG);
		582	$FILTER->title ('$AnyEvent::Log::FILTER');
		583	$FILTER->level ($ORIG_VERBOSE);
		584
		585	$COLLECT->slaves ($FILTER);
		586	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		587
		588	_reassess;
		589	}
		590
		591	# override AE::log/logger
		592	AnyEvent::log = AE::log = \&log;
		593	AnyEvent::logger = AE::logger = \&logger;
		594
		595	# convert AnyEvent loggers to AnyEvent::Log loggers
		596	$_->[0] = ctx $_->[0] # convert "pkg" to "ctx"
		597	for values %LOGGER;
		598
		599	# create the default logger contexts
		600	$LOG = ctx undef;
		601	$FILTER = ctx undef;
		602	$COLLECT = ctx undef;
		603
		604	AnyEvent::Log::reset;
		605
		606	# hello, CPAN, please catch me
		607	package AnyEvent::Log::LOG;
		608	package AE::Log::LOG;
		609	package AnyEvent::Log::FILTER;
		610	package AE::Log::FILTER;
		611	package AnyEvent::Log::COLLECT;
		612	package AE::Log::COLLECT;
		613
		614	package AnyEvent::Log::Ctx;
		615
		616	# 0 1 2 3 4
		617	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		618
		619	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		620
		621	This is a convenience constructor that makes it simpler to construct
		622	anonymous logging contexts.
		623
		624	Each key-value pair results in an invocation of the method of the same
		625	name as the key with the value as parameter, unless the value is an
		626	arrayref, in which case it calls the method with the contents of the
		627	array. The methods are called in the same order as specified.
		628
		629	Example: create a new logging context and set both the default logging
		630	level, some slave contexts and a logging callback.
		631
		632	$ctx = new AnyEvent::Log::Ctx
		633	title => "dubious messages",
		634	level => "error",
		635	log_cb => sub { print STDOUT shift; 0 },
		636	slaves => [$ctx1, $ctx, $ctx2],
		637	;
		638
		639	=back
		640
		641	=cut
		642
		643	sub new {
		644	my $class = shift;
		645
		646	my $ctx = AnyEvent::Log::ctx undef;
		647
		648	while (@_) {
		649	my ($k, $v) = splice @_, 0, 2;
		650	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		651	}
		652
		653	bless $ctx, $class # do we really support subclassing, hmm?
		654	}
		655
		656
		657	=head2 CONFIGURING A LOG CONTEXT
		658
		659	The following methods can be used to configure the logging context.
		660
		661	=over 4
		662
		663	=item $ctx->title ([$new_title])
		664
		665	Returns the title of the logging context - this is the package name, for
		666	package contexts, and a user defined string for all others.
		667
		668	If C<$new_title> is given, then it replaces the package name or title.
		669
		670	=cut
		671
		672	sub title {
		673	$_[0][0] = $_[1] if @_ > 1;
		674	$_[0][0]
		675	}
		676
		677	=back
		678
		679	=head3 LOGGING LEVELS
		680
		681	The following methods deal with the logging level set associated with the
		682	log context.
		683
		684	The most common method to use is probably C<< $ctx->level ($level) >>,
		685	which configures the specified and any higher priority levels.
		686
		687	All functions which accept a list of levels also accept the special string
		688	C<all> which expands to all logging levels.
		689
		690	=over 4
		691
		692	=item $ctx->levels ($level[, $level...)
		693
		694	Enables logging for the given levels and disables it for all others.
		695
		696	=item $ctx->level ($level)
		697
		698	Enables logging for the given level and all lower level (higher priority)
		699	ones. In addition to normal logging levels, specifying a level of C<0> or
		700	C<off> disables all logging for this level.
		701
		702	Example: log warnings, errors and higher priority messages.
		703
		704	$ctx->level ("warn");
		705	$ctx->level (5); # same thing, just numeric
		706
		707	=item $ctx->enable ($level[, $level...])
		708
		709	Enables logging for the given levels, leaving all others unchanged.
		710
		711	=item $ctx->disable ($level[, $level...])
		712
		713	Disables logging for the given levels, leaving all others unchanged.
		714
		715	=cut
		716
		717	sub _lvl_lst {
		718	map {
		719	$_ > 0 && $_ <= 9 ? $_+0
		720	: $_ eq "all" ? (1 .. 9)
		721	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
		722	} @_
		723	}
		724
		725	our $NOP_CB = sub { 0 };
		726
		727	sub levels {
		728	my $ctx = shift;
		729	$ctx->[1] = 0;
		730	$ctx->[1] \|= 1 << $_
		731	for &_lvl_lst;
		732	AnyEvent::Log::_reassess;
		733	}
		734
		735	sub level {
		736	my $ctx = shift;
		737	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		738
		739	$ctx->[1] = ((1 << $lvl) - 1) << 1;
		740	AnyEvent::Log::_reassess;
		741	}
		742
		743	sub enable {
		744	my $ctx = shift;
		745	$ctx->[1] \|= 1 << $_
		746	for &_lvl_lst;
		747	AnyEvent::Log::_reassess;
		748	}
		749
		750	sub disable {
		751	my $ctx = shift;
		752	$ctx->[1] &= ~(1 << $_)
		753	for &_lvl_lst;
		754	AnyEvent::Log::_reassess;
		755	}
		756
		757	=back
		758
		759	=head3 SLAVE CONTEXTS
		760
		761	The following methods attach and detach another logging context to a
		762	logging context.
		763
		764	Log messages are propagated to all slave contexts, unless the logging
		765	callback consumes the message.
		766
		767	=over 4
		768
		769	=item $ctx->attach ($ctx2[, $ctx3...])
		770
		771	Attaches the given contexts as slaves to this context. It is not an error
		772	to add a context twice (the second add will be ignored).
		773
		774	A context can be specified either as package name or as a context object.
		775
		776	=item $ctx->detach ($ctx2[, $ctx3...])
		777
		778	Removes the given slaves from this context - it's not an error to attempt
		779	to remove a context that hasn't been added.
		780
		781	A context can be specified either as package name or as a context object.
		782
		783	=item $ctx->slaves ($ctx2[, $ctx3...])
		784
		785	Replaces all slaves attached to this context by the ones given.
		786
		787	=cut
		788
		789	sub attach {
		790	my $ctx = shift;
		791
		792	$ctx->[2]{$_+0} = $_
		793	for map { AnyEvent::Log::ctx $_ } @_;
		794	}
		795
		796	sub detach {
		797	my $ctx = shift;
		798
		799	delete $ctx->[2]{$_+0}
		800	for map { AnyEvent::Log::ctx $_ } @_;
		801	}
		802
		803	sub slaves {
		804	undef $_[0][2];
		805	&attach;
		806	}
		807
		808	=back
		809
		810	=head3 LOG TARGETS
		811
		812	The following methods configure how the logging context actually does
		813	the logging (which consists of formatting the message and printing it or
		814	whatever it wants to do with it).
		815
		816	=over 4
		817
		818	=item $ctx->log_cb ($cb->($str)
		819
		820	Replaces the logging callback on the context (C<undef> disables the
		821	logging callback).
		822
		823	The logging callback is responsible for handling formatted log messages
		824	(see C<fmt_cb> below) - normally simple text strings that end with a
		825	newline (and are possibly multiline themselves).
		826
		827	It also has to return true iff it has consumed the log message, and false
		828	if it hasn't. Consuming a message means that it will not be sent to any
		829	slave context. When in doubt, return C<0> from your logging callback.
		830
		831	Example: a very simple logging callback, simply dump the message to STDOUT
		832	and do not consume it.
		833
		834	$ctx->log_cb (sub { print STDERR shift; 0 });
		835
		836	You can filter messages by having a log callback that simply returns C<1>
		837	and does not do anything with the message, but this counts as "message
		838	being logged" and might not be very efficient.
		839
		840	Example: propagate all messages except for log levels "debug" and
		841	"trace". The messages will still be generated, though, which can slow down
		842	your program.
		843
		844	$ctx->levels ("debug", "trace");
		845	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		846
		847	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
		848
		849	Replaces the formatting callback on the context (C<undef> restores the
		850	default formatter).
		851
		852	The callback is passed the (possibly fractional) timestamp, the original
		853	logging context, the (numeric) logging level and the raw message string
		854	and needs to return a formatted log message. In most cases this will be a
		855	string, but it could just as well be an array reference that just stores
		856	the values.
		857
		858	If, for some reason, you want to use C<caller> to find out more baout the
		859	logger then you should walk up the call stack until you are no longer
		860	inside the C<AnyEvent::Log> package.
		861
		862	Example: format just the raw message, with numeric log level in angle
		863	brackets.
		864
		865	$ctx->fmt_cb (sub {
		866	my ($time, $ctx, $lvl, $msg) = @_;
		867
		868	"<$lvl>$msg\n"
		869	});
		870
		871	Example: return an array reference with just the log values, and use
		872	C<PApp::SQL::sql_exec> to store the emssage in a database.
		873
		874	$ctx->fmt_cb (sub { \@_ });
		875	$ctx->log_cb (sub {
		876	my ($msg) = @_;
		877
		878	sql_exec "insert into log (when, subsys, prio, msg) values (?, ?, ?, ?)",
		879	$msg->[0] + 0,
		880	"$msg->[1]",
		881	$msg->[2] + 0,
		882	"$msg->[3]";
		883
		884	0
		885	});
		886
		887	=item $ctx->log_to_warn
		888
		889	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		890	(usually this logs to STDERR).
		891
		892	=item $ctx->log_to_file ($path)
		893
		894	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		895
		896	=item $ctx->log_to_path ($path)
		897
		898	Same as C<< ->log_to_file >>, but opens the file for each message. This
		899	is much slower, but allows you to change/move/rename/delete the file at
		900	basically any time.
		901
		902	Needless(?) to say, if you do not want to be bitten by some evil person
		903	calling C<chdir>, the path should be absolute. Doesn't help with
		904	C<chroot>, but hey...
		905
		906	=item $ctx->log_to_syslog ([$facility])
		907
		908	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
		909	all the others in the obvious way. If specified, then the C<$facility> is
		910	used as the facility (C<user>, C<auth>, C<local0> and so on). The default
		911	facility is C<user>.
		912
		913	Note that this function also sets a C<fmt_cb> - the logging part requires
		914	an array reference with [$level, $str] as input.
		915
		916	=cut
		917
		918	sub log_cb {
		919	my ($ctx, $cb) = @_;
		920
		921	$ctx->[3] = $cb;
		922	}
		923
		924	sub fmt_cb {
		925	my ($ctx, $cb) = @_;
		926
		927	$ctx->[4] = $cb;
		928	}
		929
		930	sub log_to_warn {
		931	my ($ctx, $path) = @_;
		932
		933	$ctx->log_cb (sub {
		934	warn shift;
		935	0
		936	});
		937	}
		938
		939	sub log_to_file {
		940	my ($ctx, $path) = @_;
		941
		942	open my $fh, ">>", $path
		943	or die "$path: $!";
		944
		945	$ctx->log_cb (sub {
		946	syswrite $fh, shift;
		947	0
		948	});
		949	}
		950
		951	sub log_to_path {
		952	my ($ctx, $path) = @_;
		953
		954	$ctx->log_cb (sub {
		955	open my $fh, ">>", $path
		956	or die "$path: $!";
		957
		958	syswrite $fh, shift;
		959	0
		960	});
		961	}
		962
		963	sub log_to_syslog {
		964	my ($ctx, $facility) = @_;
		965
		966	require Sys::Syslog;
		967
		968	$ctx->fmt_cb (sub {
		969	my $str = $_[3];
		970	$str =~ s/\n(?=.)/\n+ /g;
		971
		972	[$_[2], "($_[1][0]) $str"]
		973	});
		974
		975	$facility \|\|= "user";
		976
		977	$ctx->log_cb (sub {
		978	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		979
		980	Sys::Syslog::syslog ("$facility\|" . ($lvl - 1), $_)
		981	for split /\n/, $_[0][1];
		982
		983	0
		984	});
		985	}
		986
		987	=back
		988
		989	=head3 MESSAGE LOGGING
		990
		991	These methods allow you to log messages directly to a context, without
		992	going via your package context.
		993
		994	=over 4
		995
		996	=item $ctx->log ($level, $msg[, @params])
		997
		998	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		999
		1000	=item $logger = $ctx->logger ($level[, \$enabled])
		1001
		1002	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		1003	context.
		1004
		1005	=cut
		1006
		1007	*log = \&AnyEvent::Log::_log;
		1008	*logger = \&AnyEvent::Log::_logger;
		1009
		1010	=back
		1011
		1012	=cut
		1013
		1014	package AnyEvent::Log;
		1015
		1016	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		1017
		1018	Logging can also be configured by setting the environment variable
		1019	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		1020
		1021	The value consists of one or more logging context specifications separated
		1022	by C<:> or whitespace. Each logging specification in turn starts with a
		1023	context name, followed by C<=>, followed by zero or more comma-separated
		1024	configuration directives, here are some examples:
		1025
		1026	# set default logging level
		1027	filter=warn
		1028
		1029	# log to file instead of to stderr
		1030	log=file=/tmp/mylog
		1031
		1032	# log to file in addition to stderr
		1033	log=+%file:%file=file=/tmp/mylog
		1034
		1035	# enable debug log messages, log warnings and above to syslog
		1036	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		1037
		1038	# log trace messages (only) from AnyEvent::Debug to file
		1039	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		1040
		1041	A context name in the log specification can be any of the following:
		1042
		1043	=over 4
		1044
		1045	=item C<collect>, C<filter>, C<log>
		1046
		1047	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		1048	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		1049
		1050	=item C<%name>
		1051
		1052	Context names starting with a C<%> are anonymous contexts created when the
		1053	name is first mentioned. The difference to package contexts is that by
		1054	default they have no attached slaves.
		1055
		1056	=item a perl package name
		1057
		1058	Any other string references the logging context associated with the given
		1059	Perl C<package>. In the unlikely case where you want to specify a package
		1060	context that matches on of the other context name forms, you can add a
		1061	C<::> to the package name to force interpretation as a package.
		1062
		1063	=back
		1064
		1065	The configuration specifications can be any number of the following:
		1066
		1067	=over 4
		1068
		1069	=item C<stderr>
		1070
		1071	Configures the context to use Perl's C<warn> function (which typically
		1072	logs to C<STDERR>). Works like C<log_to_warn>.
		1073
		1074	=item C<file=>I<path>
		1075
		1076	Configures the context to log to a file with the given path. Works like
		1077	C<log_to_file>.
		1078
		1079	=item C<path=>I<path>
		1080
		1081	Configures the context to log to a file with the given path. Works like
		1082	C<log_to_path>.
		1083
		1084	=item C<syslog> or C<syslog=>I<expr>
		1085
		1086	Configures the context to log to syslog. If I<expr> is given, then it is
		1087	evaluated in the L<Sys::Syslog> package, so you could use:
		1088
		1089	log=syslog=LOG_LOCAL0
		1090
		1091	=item C<nolog>
		1092
		1093	Configures the context to not log anything by itself, which is the
		1094	default. Same as C<< $ctx->log_cb (undef) >>.
		1095
		1096	=item C<0> or C<off>
		1097
		1098	Sets the logging level of the context ot C<0>, i.e. all messages will be
		1099	filtered out.
		1100
		1101	=item C<all>
		1102
		1103	Enables all logging levels, i.e. filtering will effectively be switched
		1104	off (the default).
		1105
		1106	=item C<only>
		1107
		1108	Disables all logging levels, and changes the interpretation of following
		1109	level specifications to enable the specified level only.
		1110
		1111	Example: only enable debug messages for a context.
		1112
		1113	context=only,debug
		1114
		1115	=item C<except>
		1116
		1117	Enables all logging levels, and changes the interpretation of following
		1118	level specifications to disable that level. Rarely used.
		1119
		1120	Example: enable all logging levels except fatal and trace (this is rather
		1121	nonsensical).
		1122
		1123	filter=exept,fatal,trace
		1124
		1125	=item C<level>
		1126
		1127	Enables all logging levels, and changes the interpretation of following
		1128	level specifications to be "that level or any higher priority
		1129	message". This is the default.
		1130
		1131	Example: log anything at or above warn level.
		1132
		1133	filter=warn
		1134
		1135	# or, more verbose
		1136	filter=only,level,warn
		1137
		1138	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1139
		1140	A numeric loglevel or the name of a loglevel will be interpreted according
		1141	to the most recent C<only>, C<except> or C<level> directive. By default,
		1142	specifying a logging level enables that and any higher priority messages.
		1143
		1144	=item C<+>I<context>
		1145
		1146	Attaches the named context as slave to the context.
		1147
		1148	=item C<+>
		1149
		1150	A line C<+> detaches all contexts, i.e. clears the slave list from the
		1151	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1152	but package contexts have the parent context as slave by default.
		1153
		1154	Example: log messages from My::Module to a file, do not send them to the
		1155	default log collector.
		1156
		1157	My::Module=+,file=/tmp/mymodulelog
		1158
		1159	=back
		1160
		1161	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1162	usual, so to log to a file containing a comma, colon, backslash and some
		1163	spaces in the filename, you would do this:
		1164
		1165	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1166
		1167	Since whitespace (which includes newlines) is allowed, it is fine to
		1168	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1169
		1170	PERL_ANYEVENT_LOG="
		1171	filter=warn
		1172	AnyEvent::Debug=+%trace
		1173	%trace=only,trace,+log
		1174	" myprog
		1175
		1176	Also, in the unlikely case when you want to concatenate specifications,
		1177	use whitespace as separator, as C<::> will be interpreted as part of a
		1178	module name, an empty spec with two separators:
		1179
		1180	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1181
		1182	=cut
		1183
		1184	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1185	my %anon;
		1186
		1187	my $pkg = sub {
		1188	$_[0] eq "log" ? $LOG
		1189	: $_[0] eq "filter" ? $FILTER
		1190	: $_[0] eq "collect" ? $COLLECT
		1191	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= ctx undef)
		1192	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1193	: die # never reached?
		1194	};
		1195
		1196	/\G[[:space:]]+/gc; # skip initial whitespace
		1197
		1198	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1199	my $ctx = $pkg->($1);
		1200	my $level = "level";
		1201
		1202	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1203	for ("$1") {
		1204	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1205	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1206	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1207	} elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ($1);
		1208	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1209	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1210	} elsif ($_ eq "+" ) { $ctx->slaves;
		1211	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1212	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1213	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1214	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1215	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1216	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1217	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1218	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1219	}
		1220	}
		1221
		1222	/\G,/gc or last;
		1223	}
		1224
		1225	/\G[:[:space:]]+/gc or last;
		1226	}
		1227
		1228	/\G[[:space:]]+/gc; # skip trailing whitespace
		1229
		1230	if (/\G(.+)/g) {
		1231	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1232	}
		1233	}
		1234
253	1;	1235	1;
		1236
		1237	=head1 EXAMPLES
		1238
		1239	This section shows some common configurations, both as code, and as
		1240	C<PERL_ANYEVENT_LOG> string.
		1241
		1242	=over 4
		1243
		1244	=item Setting the global logging level.
		1245
		1246	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1247	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1248	the root context at runtime:
		1249
		1250	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1251
		1252	PERL_ANYEVENT_LOG=log=warn
		1253
		1254	$AnyEvent::Log::FILTER->level ("warn");
		1255
		1256	=item Append all messages to a file instead of sending them to STDERR.
		1257
		1258	This is affected by the global logging level.
		1259
		1260	$AnyEvent::Log::LOG->log_to_file ($path);
		1261
		1262	PERL_ANYEVENT_LOG=log=file=/some/path
		1263
		1264	=item Write all messages with priority C<error> and higher to a file.
		1265
		1266	This writes them only when the global logging level allows it, because
		1267	it is attached to the default context which is invoked I<after> global
		1268	filtering.
		1269
		1270	$AnyEvent::Log::FILTER->attach (
		1271	new AnyEvent::Log::Ctx log_to_file => $path);
		1272
		1273	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1274
		1275	This writes them regardless of the global logging level, because it is
		1276	attached to the toplevel context, which receives all messages I<before>
		1277	the global filtering.
		1278
		1279	$AnyEvent::Log::COLLECT->attach (
		1280	new AnyEvent::Log::Ctx log_to_file => $path);
		1281
		1282	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1283
		1284	In both cases, messages are still written to STDERR.
		1285
		1286	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1287
		1288	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1289	context - this simply circumvents the global filtering for trace messages.
		1290
		1291	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1292	$debug->attach ($AnyEvent::Log::LOG);
		1293
		1294	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1295
		1296	This of course works for any package, not just L<AnyEvent::Debug>, but
		1297	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1298	default.
254		1299
255	=back	1300	=back
256		1301
257	=head1 AUTHOR	1302	=head1 AUTHOR
258		1303
259	Marc Lehmann <schmorp@schmorp.de>	1304	Marc Lehmann <schmorp@schmorp.de>
260	http://home.schmorp.de/	1305	http://home.schmorp.de/
261		1306
262	=cut	1307	=cut
		1308

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs. Revision 1.44 by root, Mon Sep 26 11:32:19 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs.
Revision 1.44 by root, Mon Sep 26 11:32:19 2011 UTC