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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.17 by root, Sat Aug 20 02:21:53 2011 UTC vs.
Revision 1.52 by root, Thu Mar 22 19:27:30 2012 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 use	7	Simple uses:
		8
8	use AnyEvent;	9	use AnyEvent;
9		10
10	AE::log debug => "hit my knee";	11	AE::log fatal => "no config found, cannot continue"; # never returns
11	AE::log warn => "it's a bit too hot";	12	AE::log alert => "the battery died";
12	AE::log error => "the flag was false!";	13	AE::log crit => "the battery temperature is too hot";
13	AE::log fatal => "the bit toggled! run!";	14	AE::log error => "division by zero attempted";
		15	AE::log warn => "couldn't delete the file";
		16	AE::log note => "wanted to create config, but config already exists";
		17	AE::log info => "file soandso successfully deleted";
		18	AE::log debug => "the function returned 3";
		19	AE::log trace => "going to call function abc";
14		20
15	# "complex" use	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
16	use AnyEvent::Log;	36	use AnyEvent::Log;
17		37
18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;	38	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19		39
20	$tracer->("i am here") if $trace;	40	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	41	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		42
23	# configuration	43	Configuration (also look at the EXAMPLES section):
24		44
25	# set logging for this package to errors and higher only	45	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("error");	46	AnyEvent::Log::ctx->level ("error");
27		47
28	# set logging globally to anything below debug	48	# set logging level to suppress anything below "notice"
29	$AnyEvent::Log::Root->level ("notice");	49	$AnyEvent::Log::FILTER->level ("notice");
30		50
31	# see also EXAMPLES, below	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	);
32		57
33	=head1 DESCRIPTION	58	=head1 DESCRIPTION
34		59
35	This module implements a relatively simple "logging framework". It doesn't	60	This module implements a relatively simple "logging framework". It doesn't
36	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
37	AnyEvent - AnyEvent simply creates logging messages internally, and this	62	AnyEvent - AnyEvent simply creates logging messages internally, and this
38	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
39	using it from other modules as well.	64	using it from other modules as well.
40		65
41	Remember that the default verbosity level is C<0>, so nothing will be	66	Remember that the default verbosity level is C<4> (C<error>), so only
42	logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before	67	errors and more important messages will be logged, unless you set
43	starting your program, or change the logging level at runtime with	68	C<PERL_ANYEVENT_VERBOSE> to a higher number before starting your program
44	something like:	69	(C<AE_VERBOSE=5> is recommended during development), or change the logging
		70	level at runtime with something like:
45		71
46	use AnyEvent;	72	use AnyEvent::Log;
47	(AnyEvent::Log::ctx "")->level ("info");	73	$AnyEvent::Log::FILTER->level ("info");
48		74
49	The design goal behind this module was to keep it simple (and small),	75	The design goal behind this module was to keep it simple (and small),
50	but make it powerful enough to be potentially useful for any module, and	76	but make it powerful enough to be potentially useful for any module, and
51	extensive enough for the most common tasks, such as logging to multiple	77	extensive enough for the most common tasks, such as logging to multiple
52	targets, or being able to log into a database.	78	targets, or being able to log into a database.
53		79
		80	The module is also usable before AnyEvent itself is initialised, in which
		81	case some of the functionality might be reduced.
		82
54	The amount of documentation might indicate otherwise, but the module is	83	The amount of documentation might indicate otherwise, but the runtime part
55	still just 240 lines or so.	84	of the module is still just below 300 lines of code.
		85
		86	=head1 LOGGING LEVELS
		87
		88	Logging levels in this module range from C<1> (highest priority) to C<9>
		89	(lowest priority). Note that the lowest numerical value is the highest
		90	priority, so when this document says "higher priority" it means "lower
		91	numerical value".
		92
		93	Instead of specifying levels by name you can also specify them by aliases:
		94
		95	LVL NAME SYSLOG PERL NOTE
		96	1 fatal emerg exit system unusable, aborts program!
		97	2 alert failure in primary system
		98	3 critical crit failure in backup system
		99	4 error err die non-urgent program errors, a bug
		100	5 warn warning possible problem, not necessarily error
		101	6 note notice unusual conditions
		102	7 info normal messages, no action required
		103	8 debug debugging messages for development
		104	9 trace copious tracing output
		105
		106	As you can see, some logging levels have multiple aliases - the first one
		107	is the "official" name, the second one the "syslog" name (if it differs)
		108	and the third one the "perl" name, suggesting (only!) that you log C<die>
		109	messages at C<error> priority. The NOTE column tries to provide some
		110	rationale on how to chose a logging level.
		111
		112	As a rough guideline, levels 1..3 are primarily meant for users of the
		113	program (admins, staff), and are the only ones logged to STDERR by
		114	default. Levels 4..6 are meant for users and developers alike, while
		115	levels 7..9 are usually meant for developers.
		116
		117	You can normally only log a message once at highest priority level (C<1>,
		118	C<fatal>), because logging a fatal message will also quit the program - so
		119	use it sparingly :)
		120
		121	For example, a program that finds an unknown switch on the commandline
		122	might well use a fatal logging level to tell users about it - the "system"
		123	in this case would be the program, or module.
		124
		125	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		126	or C<all> - these are only valid for the methods that documented them.
56		127
57	=head1 LOGGING FUNCTIONS	128	=head1 LOGGING FUNCTIONS
58		129
59	These functions allow you to log messages. They always use the caller's	130	The following functions allow you to log messages. They always use the
60	package as a "logging module/source". Also, the main logging function is	131	caller's package as a "logging context". Also, the main logging function,
61	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	132	C<log>, is aliased to C<AnyEvent::log> and C<AE::log> when the C<AnyEvent>
62	loaded.	133	module is loaded.
63		134
64	=over 4	135	=over 4
65		136
66	=cut	137	=cut
67		138
68	package AnyEvent::Log;	139	package AnyEvent::Log;
69		140
70	use Carp ();	141	use Carp ();
71	use POSIX ();	142	use POSIX ();
72		143
		144	# layout of a context
		145	# 0 1 2 3 4, 5
		146	# [$title, $level, %$slaves, &$logcb, &$fmtcb, $cap]
		147
73	use AnyEvent (); BEGIN { AnyEvent::common_sense }	148	use AnyEvent (); BEGIN { AnyEvent::common_sense }
74	use AnyEvent::Util ();	149	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
75		150
76	our $VERSION = $AnyEvent::VERSION;	151	our $VERSION = $AnyEvent::VERSION;
		152
		153	our ($COLLECT, $FILTER, $LOG);
77		154
78	our ($now_int, $now_str1, $now_str2);	155	our ($now_int, $now_str1, $now_str2);
79		156
80	# Format Time, not public - yet?	157	# Format Time, not public - yet?
81	sub ft($) {	158	sub ft($) {
…		…
86	if $now_int != $i;	163	if $now_int != $i;
87		164
88	"$now_str1$f$now_str2"	165	"$now_str1$f$now_str2"
89	}	166	}
90		167
91	our %CTX; # all logging contexts	168	our %CTX; # all package contexts
92		169
93	# creates a default package context object for the given package	170	# creates a default package context object for the given package
94	sub _pkg_ctx($) {	171	sub _pkg_ctx($) {
95	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	172	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
96		173
97	# link "parent" package	174	# link "parent" package
98	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";	175	my $parent = $_[0] =~ /^(.+)::/
		176	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		177	: $COLLECT;
99		178
100	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
101	$ctx->[2]{$pkg+0} = $pkg;	179	$ctx->[2]{$parent+0} = $parent;
102		180
103	$ctx	181	$ctx
104	}	182	}
105		183
106	=item AnyEvent::Log::log $level, $msg[, @args]	184	=item AnyEvent::Log::log $level, $msg[, @args]
107		185
108	Requests logging of the given C<$msg> with the given log level (1..9).	186	Requests logging of the given C<$msg> with the given log level, and
109	You can also use the following strings as log level: C<fatal> (1),	187	returns true if the message was logged I<somewhere>.
110	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
111	C<info> (7), C<debug> (8), C<trace> (9).
112		188
113	For C<fatal> log levels, the program will abort.	189	For loglevel C<fatal>, the program will abort.
114		190
115	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	191	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
116	C<$msg> is interpreted as an sprintf format string.	192	C<$msg> is interpreted as an sprintf format string.
117		193
118	The C<$msg> should not end with C<\n>, but may if that is convenient for	194	The C<$msg> should not end with C<\n>, but may if that is convenient for
…		…
121	Last not least, C<$msg> might be a code reference, in which case it is	197	Last not least, C<$msg> might be a code reference, in which case it is
122	supposed to return the message. It will be called only then the message	198	supposed to return the message. It will be called only then the message
123	actually gets logged, which is useful if it is costly to create the	199	actually gets logged, which is useful if it is costly to create the
124	message in the first place.	200	message in the first place.
125		201
		202	This function takes care of saving and restoring C<$!> and C<$@>, so you
		203	don't have to.
		204
126	Whether the given message will be logged depends on the maximum log level	205	Whether the given message will be logged depends on the maximum log level
127	and the caller's package.	206	and the caller's package. The return value can be used to ensure that
		207	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		208	runtime error it tries to log it at C<die> level, but if that message is
		209	lost it simply uses warn.
128		210
129	Note that you can (and should) call this function as C<AnyEvent::log> or	211	Note that you can (and should) call this function as C<AnyEvent::log> or
130	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	212	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
131	need any additional functionality), as those functions will load the	213	need any additional functionality), as those functions will load the
132	logging module on demand only. They are also much shorter to write.	214	logging module on demand only. They are also much shorter to write.
…		…
149		231
150	=cut	232	=cut
151		233
152	# also allow syslog equivalent names	234	# also allow syslog equivalent names
153	our %STR2LEVEL = (	235	our %STR2LEVEL = (
154	fatal => 1, emerg => 1,	236	fatal => 1, emerg => 1, exit => 1,
155	alert => 2,	237	alert => 2,
156	critical => 3, crit => 3,	238	critical => 3, crit => 3,
157	error => 4, err => 4,	239	error => 4, err => 4, die => 4,
158	warn => 5, warning => 5,	240	warn => 5, warning => 5,
159	note => 6, notice => 6,	241	note => 6, notice => 6,
160	info => 7,	242	info => 7,
161	debug => 8,	243	debug => 8,
162	trace => 9,	244	trace => 9,
163	);	245	);
164		246
165	sub now () { time }	247	our $TIME_EXACT;
		248
		249	sub exact_time($) {
		250	$TIME_EXACT = shift;
		251	*_ts = $AnyEvent::MODEL
		252	? $TIME_EXACT ? \&AE::now : \&AE::time
		253	: sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
		254	}
		255
		256	BEGIN {
		257	exact_time 0;
		258	}
166		259
167	AnyEvent::post_detect {	260	AnyEvent::post_detect {
168	*now = \&AE::now;	261	exact_time $TIME_EXACT;
169	};	262	};
170		263
171	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	264	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
172		265
173	# time, ctx, level, msg	266	# time, ctx, level, msg
…		…
183	}	276	}
184		277
185	join "", @res	278	join "", @res
186	}	279	}
187		280
		281	sub fatal_exit() {
		282	exit 1;
		283	}
		284
188	sub _log {	285	sub _log {
189	my ($ctx, $level, $format, @args) = @_;	286	my ($ctx, $level, $format, @args) = @_;
190		287
191	$level = $level > 0 && $level <= 9	288	$level = $level > 0 && $level <= 9
192	? $level+0	289	? $level+0
193	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	290	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
194		291
195	my $mask = 1 << $level;	292	my $mask = 1 << $level;
196		293
197	my (%seen, @ctx, $now, $fmt);	294	my ($success, %seen, @ctx, $now, @fmt);
198		295
199	do	296	do
200	{	297	{
201	# skip if masked	298	# if !ref, then it's a level number
		299	if (!ref $ctx) {
		300	$level = $ctx;
202	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {	301	} elsif ($ctx->[1] & $mask and !$seen{$ctx+0}++) {
		302	# logging/recursing into this context
		303
		304	# level cap
		305	if ($ctx->[5] > $level) {
		306	push @ctx, $level; # restore level when going up in tree
		307	$level = $ctx->[5];
		308	}
		309
		310	# log if log cb
203	if ($ctx->[3]) {	311	if ($ctx->[3]) {
204	# logging target found	312	# logging target found
		313
		314	local ($!, $@);
205		315
206	# now get raw message, unless we have it already	316	# now get raw message, unless we have it already
207	unless ($now) {	317	unless ($now) {
208	$format = $format->() if ref $format;	318	$format = $format->() if ref $format;
209	$format = sprintf $format, @args if @args;	319	$format = sprintf $format, @args if @args;
210	$format =~ s/\n$//;	320	$format =~ s/\n$//;
211	$now = AE::now;	321	$now = _ts;
212	};	322	};
213		323
214	# format msg	324	# format msg
215	my $str = $ctx->[4]	325	my $str = $ctx->[4]
216	? $ctx->[4]($now, $_[0], $level, $format)	326	? $ctx->[4]($now, $_[0], $level, $format)
217	: $fmt \|\|= _format $now, $_[0], $level, $format;	327	: ($fmt[$level] \|\|= _format $now, $_[0], $level, $format);
218		328
		329	$success = 1;
		330
219	$ctx->[3]($str);	331	$ctx->[3]($str)
		332	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		333	} else {
		334	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
220	}	335	}
221
222	# not masked, not consumed - propagate to parent contexts
223	push @ctx, values %{ $ctx->[2] };
224	}	336	}
225	}	337	}
226	while $ctx = pop @ctx;	338	while $ctx = pop @ctx;
227		339
228	exit 1 if $level <= 1;	340	fatal_exit if $level <= 1;
		341
		342	$success
229	}	343	}
230		344
231	sub log($$;@) {	345	sub log($$;@) {
232	_log	346	_log
233	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	347	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
234	@_;	348	@_;
235	}	349	}
236		350
237	AnyEvent::log = AE::log = \&log;
238
239	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	351	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
240		352
241	Creates a code reference that, when called, acts as if the	353	Creates a code reference that, when called, acts as if the
242	C<AnyEvent::Log::log> function was called at this point with the givne	354	C<AnyEvent::Log::log> function was called at this point with the given
243	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	355	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
244	the C<AnyEvent::Log::log> function:	356	the C<AnyEvent::Log::log> function:
245		357
246	my $debug_log = AnyEvent::Log::logger "debug";	358	my $debug_log = AnyEvent::Log::logger "debug";
247		359
…		…
307		419
308	$LOGGER{$logger+0} = $logger;	420	$LOGGER{$logger+0} = $logger;
309		421
310	_reassess $logger+0;	422	_reassess $logger+0;
311		423
		424	require AnyEvent::Util unless $AnyEvent::Util::VERSION;
312	my $guard = AnyEvent::Util::guard {	425	my $guard = AnyEvent::Util::guard (sub {
313	# "clean up"	426	# "clean up"
314	delete $LOGGER{$logger+0};	427	delete $LOGGER{$logger+0};
315	};	428	});
316		429
317	sub {	430	sub {
318	$guard if 0; # keep guard alive, but don't cause runtime overhead	431	$guard if 0; # keep guard alive, but don't cause runtime overhead
319		432
320	_log $ctx, $level, @_	433	_log $ctx, $level, @_
…		…
325	sub logger($;$) {	438	sub logger($;$) {
326	_logger	439	_logger
327	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	440	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
328	@_	441	@_
329	}	442	}
		443
		444	=item AnyEvent::Log::exact_time $on
		445
		446	By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
		447	eventloop time, for the log timestamps. After calling this function with a
		448	true value it will instead resort to C<AE::time>, i.e. fetch the current
		449	time on each log message. This only makes a difference for event loops
		450	that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
		451
		452	This setting can be changed at any time by calling this function.
		453
		454	Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
		455	initialised, this switch will also decide whether to use C<CORE::time> or
		456	C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
		457	available.
330		458
331	=back	459	=back
332		460
333	=head1 LOGGING CONTEXTS	461	=head1 LOGGING CONTEXTS
334		462
…		…
347	timestamp, context, level and string message and formats it in the way	475	timestamp, context, level and string message and formats it in the way
348	it should be logged) and a logging callback (which is responsible for	476	it should be logged) and a logging callback (which is responsible for
349	actually logging the formatted message and telling C<AnyEvent::Log>	477	actually logging the formatted message and telling C<AnyEvent::Log>
350	whether it has consumed the message, or whether it should be propagated).	478	whether it has consumed the message, or whether it should be propagated).
351		479
352	For propagation, a context can have any number of attached I<parent	480	For propagation, a context can have any number of attached I<slave
353	contexts>. Any message that is neither masked by the logging mask nor	481	contexts>. Any message that is neither masked by the logging mask nor
354	masked by the logging callback returning true will be passed to all parent	482	masked by the logging callback returning true will be passed to all slave
355	contexts.	483	contexts.
356		484
357	Each call to a logging function will log the message at most once per	485	Each call to a logging function will log the message at most once per
358	context, so it does not matter (much) if there are cycles or if the	486	context, so it does not matter (much) if there are cycles or if the
359	message can arrive at the same context via multiple paths.	487	message can arrive at the same context via multiple paths.
…		…
363	By default, all logging contexts have an full set of log levels ("all"), a	491	By default, all logging contexts have an full set of log levels ("all"), a
364	disabled logging callback and the default formatting callback.	492	disabled logging callback and the default formatting callback.
365		493
366	Package contexts have the package name as logging title by default.	494	Package contexts have the package name as logging title by default.
367		495
368	They have exactly one parent - the context of the "parent" package. The	496	They have exactly one slave - the context of the "parent" package. The
369	parent package is simply defined to be the package name without the last	497	parent package is simply defined to be the package name without the last
370	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,	498	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the	499	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
372	exception of the rule - just like the parent of any package name in	500	exception of the rule - just like the "parent" of any single-component
373	Perl is C<main>, the default parent of any top-level package context is	501	package name in Perl is C<main>, the default slave of any top-level
374	C<AnyEvent::Log::Top>.	502	package context is C<$AnyEvent::Log::COLLECT>.
375		503
376	Since perl packages form only an approximate hierarchy, this parent	504	Since perl packages form only an approximate hierarchy, this slave
377	context can of course be removed.	505	context can of course be removed.
378		506
379	All other (anonymous) contexts have no parents and an empty title by	507	All other (anonymous) contexts have no slaves and an empty title by
380	default.	508	default.
381		509
382	When the module is loaded it creates the default context called	510	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
383	C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>),	511	context that simply logs everything via C<warn>, without propagating
384	which simply logs everything via C<warn> and doesn't propagate anything
385	anywhere by default. The purpose of the default context is to provide	512	anything anywhere by default. The purpose of this context is to provide
386	a convenient place to override the global logging target or to attach	513	a convenient place to override the global logging target or to attach
387	additional log targets. It's not meant for filtering.	514	additional log targets. It's not meant for filtering.
388		515
389	It then creates the root context called C<AnyEvent::Log::Root> (also	516	It then creates the C<$AnyEvent::Log::FILTER> context whose
390	stored in C<$AnyEvent::Log::Root>) and sets its log level set to all	517	purpose is to suppress all messages with priority higher
391	levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It	518	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
392	then attached the default logging context to it. The purpose of the root	519	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
393	context is to simply provide filtering according to some global log level.	520	is to simply provide filtering according to some global log level.
394		521
395	Finally it creates the top-level package context called	522	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
396	C<AnyEvent::Log::Top> (also stored in, you might have guessed,	523	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
397	C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
398	it at default config. It's purpose is simply to collect all log messages	524	leaves it at default config. Its purpose is simply to collect all log
399	system-wide.	525	messages system-wide.
400		526
401	These three special contexts can also be referred to by the	527	The hierarchy is then:
402	package/context names C<AE::Log::Default>, C<AE::Log::Root> and
403	C<AE::Log::Top>.
404		528
		529	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		530
405	The effect of all this is that log messages, by default, wander up	531	The effect of all this is that log messages, by default, wander up to the
406	to the root context where log messages with lower priority then	532	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		533	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
407	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the	534	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
408	AnyEvent::Log::Default context to be passed to C<warn>.	535	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
409		536
410	Splitting the top level context into three contexts makes it easy to set	537	This makes it easy to set a global logging level (by modifying $FILTER),
411	a global logging level (by modifying the root context), but still allow	538	but still allow other contexts to send, for example, their debug and trace
412	other contexts to log, for example, their debug and trace messages to the
413	default target despite the global logging level, or to attach additional	539	messages to the $LOG target despite the global logging level, or to attach
414	log targets that log messages, regardless of the global logging level.	540	additional log targets that log messages, regardless of the global logging
		541	level.
415		542
416	It also makes it easy to replace the default warn-logger by something that	543	It also makes it easy to modify the default warn-logger ($LOG) to
417	logs to a file, or to attach additional logging targets.	544	something that logs to a file, or to attach additional logging targets
		545	(such as loggign to a file) by attaching it to $FILTER.
418		546
419	=head2 CREATING/FINDING/DESTROYING CONTEXTS	547	=head2 CREATING/FINDING/DESTROYING CONTEXTS
420		548
421	=over 4	549	=over 4
422		550
…		…
454	This can be used to implement config-file (re-)loading: before loading a	582	This can be used to implement config-file (re-)loading: before loading a
455	configuration, reset all contexts.	583	configuration, reset all contexts.
456		584
457	=cut	585	=cut
458		586
		587	our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
		588	$AnyEvent::VERBOSE = 9;
		589
459	sub reset {	590	sub reset {
460	# hard to kill complex data structures	591	# hard to kill complex data structures
461	# we recreate all package loggers and reset the hierarchy	592	# we "recreate" all package loggers and reset the hierarchy
462	while (my ($k, $v) = each %CTX) {	593	while (my ($k, $v) = each %CTX) {
463	@$v = ($k, (1 << 10) - 1 - 1, { });	594	@$v = ($k, (1 << 10) - 1 - 1, { });
464		595
465	my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top";	596	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
466	$v->attach ($CTX{$pkg});
467	}	597	}
468		598
469	$AnyEvent::Log::Default->parents;	599	@$_ = ($_->[0], (1 << 10) - 1 - 1)
470	$AnyEvent::Log::Default->title ("AnyEvent::Log::Default");	600	for $LOG, $FILTER, $COLLECT;
471	$AnyEvent::Log::Default->log_cb (sub {
472	warn shift;
473	0
474	});
475	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
476		601
477	$AnyEvent::Log::Root->parents ($AnyEvent::Log::Default);	602	#$LOG->slaves;
478	$AnyEvent::Log::Root->title ("AnyEvent::Log::Root");	603	$LOG->title ('$AnyEvent::Log::LOG');
479	$AnyEvent::Log::Root->level ($AnyEvent::VERBOSE);	604	$LOG->log_to_warn;
480	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
481		605
482	$AnyEvent::Log::Top->parents ($AnyEvent::Log::Root);	606	$FILTER->slaves ($LOG);
483	$AnyEvent::Log::Top->title ("AnyEvent::Log::Top");	607	$FILTER->title ('$AnyEvent::Log::FILTER');
484	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $AnyEvent::Log::Top;	608	$FILTER->level ($ORIG_VERBOSE);
		609
		610	$COLLECT->slaves ($FILTER);
		611	$COLLECT->title ('$AnyEvent::Log::COLLECT');
485		612
486	_reassess;	613	_reassess;
487	}	614	}
488		615
		616	# override AE::log/logger
		617	AnyEvent::log = AE::log = \&log;
		618	AnyEvent::logger = AE::logger = \&logger;
		619
		620	# convert AnyEvent loggers to AnyEvent::Log loggers
		621	$_->[0] = ctx $_->[0] # convert "pkg" to "ctx"
		622	for values %LOGGER;
		623
489	# create the default logger contexts	624	# create the default logger contexts
490	$AnyEvent::Log::Default = ctx undef;	625	$LOG = ctx undef;
491	$AnyEvent::Log::Root = ctx undef;	626	$FILTER = ctx undef;
492	$AnyEvent::Log::Top = ctx undef;	627	$COLLECT = ctx undef;
493		628
494	AnyEvent::Log::reset;	629	AnyEvent::Log::reset;
495		630
496	# hello, CPAN, please catch me	631	# hello, CPAN, please catch me
497	package AnyEvent::Log::Default;
498	package AE::Log::Default;
499	package AnyEvent::Log::Root;
500	package AE::Log::Root;
501	package AnyEvent::Log::Top;	632	package AnyEvent::Log::LOG;
502	package AE::Log::Top;	633	package AE::Log::LOG;
		634	package AnyEvent::Log::FILTER;
		635	package AE::Log::FILTER;
		636	package AnyEvent::Log::COLLECT;
		637	package AE::Log::COLLECT;
503		638
504	package AnyEvent::Log::Ctx;	639	package AnyEvent::Log::Ctx;
505
506	# 0 1 2 3 4
507	# [$title, $level, %$parents, &$logcb, &$fmtcb]
508		640
509	=item $ctx = new AnyEvent::Log::Ctx methodname => param...	641	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
510		642
511	This is a convenience constructor that makes it simpler to construct	643	This is a convenience constructor that makes it simpler to construct
512	anonymous logging contexts.	644	anonymous logging contexts.
…		…
515	name as the key with the value as parameter, unless the value is an	647	name as the key with the value as parameter, unless the value is an
516	arrayref, in which case it calls the method with the contents of the	648	arrayref, in which case it calls the method with the contents of the
517	array. The methods are called in the same order as specified.	649	array. The methods are called in the same order as specified.
518		650
519	Example: create a new logging context and set both the default logging	651	Example: create a new logging context and set both the default logging
520	level, some parent contexts and a logging callback.	652	level, some slave contexts and a logging callback.
521		653
522	$ctx = new AnyEvent::Log::Ctx	654	$ctx = new AnyEvent::Log::Ctx
523	title => "dubious messages",	655	title => "dubious messages",
524	level => "error",	656	level => "error",
525	log_cb => sub { print STDOUT shift; 0 },	657	log_cb => sub { print STDOUT shift; 0 },
526	parents => [$ctx1, $ctx, $ctx2],	658	slaves => [$ctx1, $ctx, $ctx2],
527	;	659	;
528		660
529	=back	661	=back
530		662
531	=cut	663	=cut
…		…
599	Enables logging for the given levels, leaving all others unchanged.	731	Enables logging for the given levels, leaving all others unchanged.
600		732
601	=item $ctx->disable ($level[, $level...])	733	=item $ctx->disable ($level[, $level...])
602		734
603	Disables logging for the given levels, leaving all others unchanged.	735	Disables logging for the given levels, leaving all others unchanged.
		736
		737	=item $ctx->cap ($level)
		738
		739	Caps the maximum priority to the given level, for all messages logged
		740	to, or passing through, this context. That is, while this doesn't affect
		741	whether a message is logged or passed on, the maximum priority of messages
		742	will be limited to the specified level - messages with a higher priority
		743	will be set to the specified priority.
		744
		745	Another way to view this is that C<< ->level >> filters out messages with
		746	a too low priority, while C<< ->cap >> modifies messages with a too high
		747	priority.
		748
		749	This is useful when different log targets have different interpretations
		750	of priority. For example, for a specific command line program, a wrong
		751	command line switch might well result in a C<fatal> log message, while the
		752	same message, logged to syslog, is likely I<not> fatal to the system or
		753	syslog facility as a whole, but more likely a mere C<error>.
		754
		755	This can be modeled by having a stderr logger that logs messages "as-is"
		756	and a syslog logger that logs messages with a level cap of, say, C<error>,
		757	or, for truly system-critical components, actually C<critical>.
604		758
605	=cut	759	=cut
606		760
607	sub _lvl_lst {	761	sub _lvl_lst {
608	map {	762	map {
…		…
610	: $_ eq "all" ? (1 .. 9)	764	: $_ eq "all" ? (1 .. 9)
611	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"	765	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
612	} @_	766	} @_
613	}	767	}
614		768
		769	sub _lvl {
		770	$_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1]
		771	}
		772
615	our $NOP_CB = sub { 0 };	773	our $NOP_CB = sub { 0 };
616		774
617	sub levels {	775	sub levels {
618	my $ctx = shift;	776	my $ctx = shift;
619	$ctx->[1] = 0;	777	$ctx->[1] = 0;
…		…
622	AnyEvent::Log::_reassess;	780	AnyEvent::Log::_reassess;
623	}	781	}
624		782
625	sub level {	783	sub level {
626	my $ctx = shift;	784	my $ctx = shift;
627	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
628
629	$ctx->[1] = ((1 << $lvl) - 1) << 1;	785	$ctx->[1] = ((1 << &_lvl) - 1) << 1;
630	AnyEvent::Log::_reassess;	786	AnyEvent::Log::_reassess;
631	}	787	}
632		788
633	sub enable {	789	sub enable {
634	my $ctx = shift;	790	my $ctx = shift;
…		…
642	$ctx->[1] &= ~(1 << $_)	798	$ctx->[1] &= ~(1 << $_)
643	for &_lvl_lst;	799	for &_lvl_lst;
644	AnyEvent::Log::_reassess;	800	AnyEvent::Log::_reassess;
645	}	801	}
646		802
		803	sub cap {
		804	my $ctx = shift;
		805	$ctx->[5] = &_lvl;
		806	}
		807
647	=back	808	=back
648		809
649	=head3 PARENT CONTEXTS	810	=head3 SLAVE CONTEXTS
650		811
651	The following methods attach and detach another logging context to a	812	The following methods attach and detach another logging context to a
652	logging context.	813	logging context.
653		814
654	Log messages are propagated to all parent contexts, unless the logging	815	Log messages are propagated to all slave contexts, unless the logging
655	callback consumes the message.	816	callback consumes the message.
656		817
657	=over 4	818	=over 4
658		819
659	=item $ctx->attach ($ctx2[, $ctx3...])	820	=item $ctx->attach ($ctx2[, $ctx3...])
660		821
661	Attaches the given contexts as parents to this context. It is not an error	822	Attaches the given contexts as slaves to this context. It is not an error
662	to add a context twice (the second add will be ignored).	823	to add a context twice (the second add will be ignored).
663		824
664	A context can be specified either as package name or as a context object.	825	A context can be specified either as package name or as a context object.
665		826
666	=item $ctx->detach ($ctx2[, $ctx3...])	827	=item $ctx->detach ($ctx2[, $ctx3...])
667		828
668	Removes the given parents from this context - it's not an error to attempt	829	Removes the given slaves from this context - it's not an error to attempt
669	to remove a context that hasn't been added.	830	to remove a context that hasn't been added.
670		831
671	A context can be specified either as package name or as a context object.	832	A context can be specified either as package name or as a context object.
672		833
673	=item $ctx->parents ($ctx2[, $ctx3...])	834	=item $ctx->slaves ($ctx2[, $ctx3...])
674		835
675	Replaces all parents attached to this context by the ones given.	836	Replaces all slaves attached to this context by the ones given.
676		837
677	=cut	838	=cut
678		839
679	sub attach {	840	sub attach {
680	my $ctx = shift;	841	my $ctx = shift;
…		…
688		849
689	delete $ctx->[2]{$_+0}	850	delete $ctx->[2]{$_+0}
690	for map { AnyEvent::Log::ctx $_ } @_;	851	for map { AnyEvent::Log::ctx $_ } @_;
691	}	852	}
692		853
693	sub parents {	854	sub slaves {
694	undef $_[0][2];	855	undef $_[0][2];
695	&attach;	856	&attach;
696	}	857	}
697		858
698	=back	859	=back
699		860
700	=head3 MESSAGE LOGGING	861	=head3 LOG TARGETS
701		862
702	The following methods configure how the logging context actually does	863	The following methods configure how the logging context actually does
703	the logging (which consists of formatting the message and printing it or	864	the logging (which consists of formatting the message and printing it or
704	whatever it wants to do with it) and also allows you to log messages	865	whatever it wants to do with it).
705	directly to a context, without going via your package context.
706		866
707	=over 4	867	=over 4
708		868
709	=item $ctx->log_cb ($cb->($str))	869	=item $ctx->log_cb ($cb->($str)
710		870
711	Replaces the logging callback on the context (C<undef> disables the	871	Replaces the logging callback on the context (C<undef> disables the
712	logging callback).	872	logging callback).
713		873
714	The logging callback is responsible for handling formatted log messages	874	The logging callback is responsible for handling formatted log messages
715	(see C<fmt_cb> below) - normally simple text strings that end with a	875	(see C<fmt_cb> below) - normally simple text strings that end with a
716	newline (and are possibly multiline themselves).	876	newline (and are possibly multiline themselves).
717		877
718	It also has to return true iff it has consumed the log message, and false	878	It also has to return true iff it has consumed the log message, and false
719	if it hasn't. Consuming a message means that it will not be sent to any	879	if it hasn't. Consuming a message means that it will not be sent to any
720	parent context. When in doubt, return C<0> from your logging callback.	880	slave context. When in doubt, return C<0> from your logging callback.
721		881
722	Example: a very simple logging callback, simply dump the message to STDOUT	882	Example: a very simple logging callback, simply dump the message to STDOUT
723	and do not consume it.	883	and do not consume it.
724		884
725	$ctx->log_cb (sub { print STDERR shift; 0 });	885	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
733	your program.	893	your program.
734		894
735	$ctx->levels ("debug", "trace");	895	$ctx->levels ("debug", "trace");
736	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	896	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
737		897
738	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	898	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
739		899
740	Replaces the formatting callback on the context (C<undef> restores the	900	Replaces the formatting callback on the context (C<undef> restores the
741	default formatter).	901	default formatter).
742		902
743	The callback is passed the (possibly fractional) timestamp, the original	903	The callback is passed the (possibly fractional) timestamp, the original
744	logging context, the (numeric) logging level and the raw message string and needs to	904	logging context (object, not title), the (numeric) logging level and
745	return a formatted log message. In most cases this will be a string, but	905	the raw message string and needs to return a formatted log message. In
746	it could just as well be an array reference that just stores the values.	906	most cases this will be a string, but it could just as well be an array
		907	reference that just stores the values.
		908
		909	If, for some reason, you want to use C<caller> to find out more about the
		910	logger then you should walk up the call stack until you are no longer
		911	inside the C<AnyEvent::Log> package.
747		912
748	Example: format just the raw message, with numeric log level in angle	913	Example: format just the raw message, with numeric log level in angle
749	brackets.	914	brackets.
750		915
751	$ctx->fmt_cb (sub {	916	$ctx->fmt_cb (sub {
…		…
753		918
754	"<$lvl>$msg\n"	919	"<$lvl>$msg\n"
755	});	920	});
756		921
757	Example: return an array reference with just the log values, and use	922	Example: return an array reference with just the log values, and use
758	C<PApp::SQL::sql_exec> to store the emssage in a database.	923	C<PApp::SQL::sql_exec> to store the message in a database.
759		924
760	$ctx->fmt_cb (sub { \@_ });	925	$ctx->fmt_cb (sub { \@_ });
761	$ctx->log_cb (sub {	926	$ctx->log_cb (sub {
762	my ($msg) = @_;	927	my ($msg) = @_;
763		928
…		…
768	"$msg->[3]";	933	"$msg->[3]";
769		934
770	0	935	0
771	});	936	});
772		937
		938	=item $ctx->log_to_warn
		939
		940	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		941	(usually this logs to STDERR).
		942
		943	=item $ctx->log_to_file ($path)
		944
		945	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		946
		947	=item $ctx->log_to_path ($path)
		948
		949	Same as C<< ->log_to_file >>, but opens the file for each message. This
		950	is much slower, but allows you to change/move/rename/delete the file at
		951	basically any time.
		952
		953	Needless(?) to say, if you do not want to be bitten by some evil person
		954	calling C<chdir>, the path should be absolute. Doesn't help with
		955	C<chroot>, but hey...
		956
		957	=item $ctx->log_to_syslog ([$facility])
		958
		959	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
		960	all the others in the obvious way. If specified, then the C<$facility> is
		961	used as the facility (C<user>, C<auth>, C<local0> and so on). The default
		962	facility is C<user>.
		963
		964	Note that this function also sets a C<fmt_cb> - the logging part requires
		965	an array reference with [$level, $str] as input.
		966
773	=cut	967	=cut
774		968
775	sub log_cb {	969	sub log_cb {
776	my ($ctx, $cb) = @_;	970	my ($ctx, $cb) = @_;
777		971
…		…
782	my ($ctx, $cb) = @_;	976	my ($ctx, $cb) = @_;
783		977
784	$ctx->[4] = $cb;	978	$ctx->[4] = $cb;
785	}	979	}
786		980
787	=item $ctx->log ($level, $msg[, @params])	981	sub log_to_warn {
		982	my ($ctx, $path) = @_;
788		983
789	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	984	$ctx->log_cb (sub {
		985	warn shift;
		986	0
		987	});
		988	}
790		989
791	=item $logger = $ctx->logger ($level[, \$enabled])	990	sub log_to_file {
792		991	my ($ctx, $path) = @_;
793	Same as C<AnyEvent::Log::logger>, but uses the given context as log
794	context.
795
796	=cut
797
798	*log = \&AnyEvent::Log::_log;
799	*logger = \&AnyEvent::Log::_logger;
800
801	1;
802
803	=back
804
805	=head1 EXAMPLES
806
807	This section shows some common configurations.
808
809	=over 4
810
811	=item Setting the global logging level.
812
813	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
814	running your program, or modify the log level of the root context:
815
816	PERL_ANYEVENT_VERBOSE=5 ./myprog
817
818	$AnyEvent::Log::Root->level ("warn");
819
820	=item Append all messages to a file instead of sending them to STDERR.
821
822	This is affected by the global logging level.
823		992
824	open my $fh, ">>", $path	993	open my $fh, ">>", $path
825	or die "$path: $!";	994	or die "$path: $!";
826		995
827	$AnyEvent::Log::Default->log_cb (sub {	996	$ctx->log_cb (sub {
828	syswrite $fh, shift;	997	syswrite $fh, shift;
829	0	998	0
830	});	999	});
		1000	}
		1001
		1002	sub log_to_path {
		1003	my ($ctx, $path) = @_;
		1004
		1005	$ctx->log_cb (sub {
		1006	open my $fh, ">>", $path
		1007	or die "$path: $!";
		1008
		1009	syswrite $fh, shift;
		1010	0
		1011	});
		1012	}
		1013
		1014	sub log_to_syslog {
		1015	my ($ctx, $facility) = @_;
		1016
		1017	require Sys::Syslog;
		1018
		1019	$ctx->fmt_cb (sub {
		1020	my $str = $_[3];
		1021	$str =~ s/\n(?=.)/\n+ /g;
		1022
		1023	[$_[2], "($_[1][0]) $str"]
		1024	});
		1025
		1026	$facility \|\|= "user";
		1027
		1028	$ctx->log_cb (sub {
		1029	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		1030
		1031	Sys::Syslog::syslog ("$facility\|" . ($lvl - 1), $_)
		1032	for split /\n/, $_[0][1];
		1033
		1034	0
		1035	});
		1036	}
		1037
		1038	=back
		1039
		1040	=head3 MESSAGE LOGGING
		1041
		1042	These methods allow you to log messages directly to a context, without
		1043	going via your package context.
		1044
		1045	=over 4
		1046
		1047	=item $ctx->log ($level, $msg[, @params])
		1048
		1049	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		1050
		1051	Example: log a message in the context of another package.
		1052
		1053	(AnyEvent::Log::ctx "Other::Package")->log (warn => "heely bo");
		1054
		1055	=item $logger = $ctx->logger ($level[, \$enabled])
		1056
		1057	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		1058	context.
		1059
		1060	=cut
		1061
		1062	*log = \&AnyEvent::Log::_log;
		1063	*logger = \&AnyEvent::Log::_logger;
		1064
		1065	=back
		1066
		1067	=cut
		1068
		1069	package AnyEvent::Log;
		1070
		1071	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		1072
		1073	Logging can also be configured by setting the environment variable
		1074	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		1075
		1076	The value consists of one or more logging context specifications separated
		1077	by C<:> or whitespace. Each logging specification in turn starts with a
		1078	context name, followed by C<=>, followed by zero or more comma-separated
		1079	configuration directives, here are some examples:
		1080
		1081	# set default logging level
		1082	filter=warn
		1083
		1084	# log to file instead of to stderr
		1085	log=file=/tmp/mylog
		1086
		1087	# log to file in addition to stderr
		1088	log=+%file:%file=file=/tmp/mylog
		1089
		1090	# enable debug log messages, log warnings and above to syslog
		1091	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		1092
		1093	# log trace messages (only) from AnyEvent::Debug to file
		1094	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		1095
		1096	A context name in the log specification can be any of the following:
		1097
		1098	=over 4
		1099
		1100	=item C<collect>, C<filter>, C<log>
		1101
		1102	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		1103	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		1104
		1105	=item C<%name>
		1106
		1107	Context names starting with a C<%> are anonymous contexts created when the
		1108	name is first mentioned. The difference to package contexts is that by
		1109	default they have no attached slaves.
		1110
		1111	=item a perl package name
		1112
		1113	Any other string references the logging context associated with the given
		1114	Perl C<package>. In the unlikely case where you want to specify a package
		1115	context that matches on of the other context name forms, you can add a
		1116	C<::> to the package name to force interpretation as a package.
		1117
		1118	=back
		1119
		1120	The configuration specifications can be any number of the following:
		1121
		1122	=over 4
		1123
		1124	=item C<stderr>
		1125
		1126	Configures the context to use Perl's C<warn> function (which typically
		1127	logs to C<STDERR>). Works like C<log_to_warn>.
		1128
		1129	=item C<file=>I<path>
		1130
		1131	Configures the context to log to a file with the given path. Works like
		1132	C<log_to_file>.
		1133
		1134	=item C<path=>I<path>
		1135
		1136	Configures the context to log to a file with the given path. Works like
		1137	C<log_to_path>.
		1138
		1139	=item C<syslog> or C<syslog=>I<expr>
		1140
		1141	Configures the context to log to syslog. If I<expr> is given, then it is
		1142	evaluated in the L<Sys::Syslog> package, so you could use:
		1143
		1144	log=syslog=LOG_LOCAL0
		1145
		1146	=item C<nolog>
		1147
		1148	Configures the context to not log anything by itself, which is the
		1149	default. Same as C<< $ctx->log_cb (undef) >>.
		1150
		1151	=item C<cap=>I<level>
		1152
		1153	Caps logging messages entering this context at the given level, i.e.
		1154	reduces the priority of messages with higher priority than this level. The
		1155	default is C<0> (or C<off>), meaning the priority will not be touched.
		1156
		1157	=item C<0> or C<off>
		1158
		1159	Sets the logging level of the context to C<0>, i.e. all messages will be
		1160	filtered out.
		1161
		1162	=item C<all>
		1163
		1164	Enables all logging levels, i.e. filtering will effectively be switched
		1165	off (the default).
		1166
		1167	=item C<only>
		1168
		1169	Disables all logging levels, and changes the interpretation of following
		1170	level specifications to enable the specified level only.
		1171
		1172	Example: only enable debug messages for a context.
		1173
		1174	context=only,debug
		1175
		1176	=item C<except>
		1177
		1178	Enables all logging levels, and changes the interpretation of following
		1179	level specifications to disable that level. Rarely used.
		1180
		1181	Example: enable all logging levels except fatal and trace (this is rather
		1182	nonsensical).
		1183
		1184	filter=exept,fatal,trace
		1185
		1186	=item C<level>
		1187
		1188	Enables all logging levels, and changes the interpretation of following
		1189	level specifications to be "that level or any higher priority
		1190	message". This is the default.
		1191
		1192	Example: log anything at or above warn level.
		1193
		1194	filter=warn
		1195
		1196	# or, more verbose
		1197	filter=only,level,warn
		1198
		1199	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1200
		1201	A numeric loglevel or the name of a loglevel will be interpreted according
		1202	to the most recent C<only>, C<except> or C<level> directive. By default,
		1203	specifying a logging level enables that and any higher priority messages.
		1204
		1205	=item C<+>I<context>
		1206
		1207	Attaches the named context as slave to the context.
		1208
		1209	=item C<+>
		1210
		1211	A lone C<+> detaches all contexts, i.e. clears the slave list from the
		1212	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1213	but package contexts have the parent context as slave by default.
		1214
		1215	Example: log messages from My::Module to a file, do not send them to the
		1216	default log collector.
		1217
		1218	My::Module=+,file=/tmp/mymodulelog
		1219
		1220	=back
		1221
		1222	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1223	usual, so to log to a file containing a comma, colon, backslash and some
		1224	spaces in the filename, you would do this:
		1225
		1226	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1227
		1228	Since whitespace (which includes newlines) is allowed, it is fine to
		1229	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1230
		1231	PERL_ANYEVENT_LOG="
		1232	filter=warn
		1233	AnyEvent::Debug=+%trace
		1234	%trace=only,trace,+log
		1235	" myprog
		1236
		1237	Also, in the unlikely case when you want to concatenate specifications,
		1238	use whitespace as separator, as C<::> will be interpreted as part of a
		1239	module name, an empty spec with two separators:
		1240
		1241	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1242
		1243	=cut
		1244
		1245	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1246	my %anon;
		1247
		1248	my $pkg = sub {
		1249	$_[0] eq "log" ? $LOG
		1250	: $_[0] eq "filter" ? $FILTER
		1251	: $_[0] eq "collect" ? $COLLECT
		1252	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= do { my $ctx = ctx undef; $ctx->[0] = $_[0]; $ctx })
		1253	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1254	: die # never reached?
		1255	};
		1256
		1257	/\G[[:space:]]+/gc; # skip initial whitespace
		1258
		1259	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1260	my $ctx = $pkg->($1);
		1261	my $level = "level";
		1262
		1263	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1264	for ("$1") {
		1265	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1266	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1267	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1268	} elsif (/^syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ("$1");
		1269	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1270	} elsif (/^cap=(.+)/ ) { $ctx->cap ("$1");
		1271	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1272	} elsif ($_ eq "+" ) { $ctx->slaves;
		1273	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1274	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1275	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1276	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1277	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1278	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1279	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1280	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1281	}
		1282	}
		1283
		1284	/\G,/gc or last;
		1285	}
		1286
		1287	/\G[:[:space:]]+/gc or last;
		1288	}
		1289
		1290	/\G[[:space:]]+/gc; # skip trailing whitespace
		1291
		1292	if (/\G(.+)/g) {
		1293	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1294	}
		1295	}
		1296
		1297	1;
		1298
		1299	=head1 EXAMPLES
		1300
		1301	This section shows some common configurations, both as code, and as
		1302	C<PERL_ANYEVENT_LOG> string.
		1303
		1304	=over 4
		1305
		1306	=item Setting the global logging level.
		1307
		1308	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1309	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1310	the root context at runtime:
		1311
		1312	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1313
		1314	PERL_ANYEVENT_LOG=log=warn
		1315
		1316	$AnyEvent::Log::FILTER->level ("warn");
		1317
		1318	=item Append all messages to a file instead of sending them to STDERR.
		1319
		1320	This is affected by the global logging level.
		1321
		1322	$AnyEvent::Log::LOG->log_to_file ($path);
		1323
		1324	PERL_ANYEVENT_LOG=log=file=/some/path
831		1325
832	=item Write all messages with priority C<error> and higher to a file.	1326	=item Write all messages with priority C<error> and higher to a file.
833		1327
834	This writes them only when the global logging level allows it, because	1328	This writes them only when the global logging level allows it, because
835	it is attached to the default context which is invoked I<after> global	1329	it is attached to the default context which is invoked I<after> global
836	filtering.	1330	filtering.
837		1331
838	open my $fh, ">>", $path	1332	$AnyEvent::Log::FILTER->attach (
839	or die "$path: $!";	1333	new AnyEvent::Log::Ctx log_to_file => $path);
840		1334
841	$AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx	1335	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
842	log_cb => sub { syswrite $fh, shift; 0 });
843		1336
844	This writes them regardless of the global logging level, because it is	1337	This writes them regardless of the global logging level, because it is
845	attached to the toplevel context, which receives all messages I<before>	1338	attached to the toplevel context, which receives all messages I<before>
846	the global filtering.	1339	the global filtering.
847		1340
848	$AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx	1341	$AnyEvent::Log::COLLECT->attach (
849	log_cb => sub { syswrite $fh, shift; 0 });	1342	new AnyEvent::Log::Ctx log_to_file => $path);
850		1343
		1344	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1345
851	In both cases, messages are still written to STDOUT.	1346	In both cases, messages are still written to STDERR.
		1347
		1348	=item Additionally log all messages with C<warn> and higher priority to
		1349	C<syslog>, but cap at C<error>.
		1350
		1351	This logs all messages to the default log target, but also logs messages
		1352	with priority C<warn> or higher (and not filtered otherwise) to syslog
		1353	facility C<user>. Messages with priority higher than C<error> will be
		1354	logged with level C<error>.
		1355
		1356	$AnyEvent::Log::LOG->attach (
		1357	new AnyEvent::Log::Ctx
		1358	level => "warn",
		1359	cap => "error",
		1360	syslog => "user",
		1361	);
		1362
		1363	PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
852		1364
853	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).	1365	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
854		1366
855	Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug>	1367	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
856	context and increase the C<AnyEvent::Debug> logging level - this simply
857	circumvents the global filtering for trace messages.	1368	context - this simply circumvents the global filtering for trace messages.
858		1369
859	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;	1370	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
860	$debug->attach ($AnyEvent::Log::Default);	1371	$debug->attach ($AnyEvent::Log::LOG);
861	$debug->levels ("trace"); # not "level"!
862		1372
863	This of course works for any package.	1373	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1374
		1375	This of course works for any package, not just L<AnyEvent::Debug>, but
		1376	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1377	default.
864		1378
865	=back	1379	=back
866		1380
867	=head1 AUTHOR	1381	=head1 AUTHOR
868		1382
869	Marc Lehmann <schmorp@schmorp.de>	1383	Marc Lehmann <schmorp@schmorp.de>
870	http://home.schmorp.de/	1384	http://home.schmorp.de/
871		1385
872	=cut	1386	=cut
		1387

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.17 by root, Sat Aug 20 02:21:53 2011 UTC vs. Revision 1.52 by root, Thu Mar 22 19:27:30 2012 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.17 by root, Sat Aug 20 02:21:53 2011 UTC vs.
Revision 1.52 by root, Thu Mar 22 19:27:30 2012 UTC