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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.15 by root, Sat Aug 20 02:16:59 2011 UTC vs.
Revision 1.53 by root, Tue Mar 27 16:21:11 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 maximum	45	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("all");	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::ctx "")->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,
32		52	# regardless of (most) other settings
33	# disable logging for package "AnyEvent" and all packages below it	53	$AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
34	AnyEvent->AnyEvent::Log::ctx->level (0);	54	level => "critical",
35		55	log_to_syslog => "user",
36	# log everything below debug to a file, for the whole program	56	);
37	my $ctx = AnyEvent::Log::ctx;
38	$ctx->log_cb (sub { print FILE shift; 0 });
39	(AnyEvent::Log::ctx "")->add ($ctx);
40		57
41	=head1 DESCRIPTION	58	=head1 DESCRIPTION
42		59
43	This module implements a relatively simple "logging framework". It doesn't	60	This module implements a relatively simple "logging framework". It doesn't
44	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
45	AnyEvent - AnyEvent simply creates logging messages internally, and this	62	AnyEvent - AnyEvent simply creates logging messages internally, and this
46	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
47	using it from other modules as well.	64	using it from other modules as well.
48		65
49	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
50	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
51	starting your program, or change the logging level at runtime with	68	C<PERL_ANYEVENT_VERBOSE> to a higher number before starting your program
52	something like:	69	(C<AE_VERBOSE=5> is recommended during development), or change the logging
		70	level at runtime with something like:
53		71
54	use AnyEvent;	72	use AnyEvent::Log;
55	(AnyEvent::Log::ctx "")->level ("info");	73	$AnyEvent::Log::FILTER->level ("info");
56		74
57	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),
58	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
59	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
60	targets, or being able to log into a database.	78	targets, or being able to log into a database.
61		79
		80	The module is also usable before AnyEvent itself is initialised, in which
		81	case some of the functionality might be reduced.
		82
62	The amount of documentation might indicate otherwise, but the module is	83	The amount of documentation might indicate otherwise, but the runtime part
63	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.
64		127
65	=head1 LOGGING FUNCTIONS	128	=head1 LOGGING FUNCTIONS
66		129
67	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
68	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,
69	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>
70	loaded.	133	module is loaded.
71		134
72	=over 4	135	=over 4
73		136
74	=cut	137	=cut
75		138
76	package AnyEvent::Log;	139	package AnyEvent::Log;
77		140
78	use Carp ();	141	use Carp ();
79	use POSIX ();	142	use POSIX ();
80		143
		144	# layout of a context
		145	# 0 1 2 3 4, 5
		146	# [$title, $level, %$slaves, &$logcb, &$fmtcb, $cap]
		147
81	use AnyEvent (); BEGIN { AnyEvent::common_sense }	148	use AnyEvent (); BEGIN { AnyEvent::common_sense }
82	use AnyEvent::Util ();	149	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
83		150
84	our $VERSION = $AnyEvent::VERSION;	151	our $VERSION = $AnyEvent::VERSION;
		152
		153	our ($COLLECT, $FILTER, $LOG);
85		154
86	our ($now_int, $now_str1, $now_str2);	155	our ($now_int, $now_str1, $now_str2);
87		156
88	# Format Time, not public - yet?	157	# Format Time, not public - yet?
89	sub ft($) {	158	sub ft($) {
…		…
94	if $now_int != $i;	163	if $now_int != $i;
95		164
96	"$now_str1$f$now_str2"	165	"$now_str1$f$now_str2"
97	}	166	}
98		167
99	our %CTX; # all logging contexts	168	our %CTX; # all package contexts
100		169
101	# creates a default package context object for the given package	170	# creates a default package context object for the given package
102	sub _pkg_ctx($) {	171	sub _pkg_ctx($) {
103	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	172	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
104		173
105	# link "parent" package	174	# link "parent" package
106	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";	175	my $parent = $_[0] =~ /^(.+)::/
		176	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		177	: $COLLECT;
107		178
108	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
109	$ctx->[2]{$pkg+0} = $pkg;	179	$ctx->[2]{$parent+0} = $parent;
110		180
111	$ctx	181	$ctx
112	}	182	}
113		183
114	=item AnyEvent::Log::log $level, $msg[, @args]	184	=item AnyEvent::Log::log $level, $msg[, @args]
115		185
116	Requests logging of the given C<$msg> with the given log level (1..9).	186	Requests logging of the given C<$msg> with the given log level, and
117	You can also use the following strings as log level: C<fatal> (1),	187	returns true if the message was logged I<somewhere>.
118	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
119	C<info> (7), C<debug> (8), C<trace> (9).
120		188
121	For C<fatal> log levels, the program will abort.	189	For loglevel C<fatal>, the program will abort.
122		190
123	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	191	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
124	C<$msg> is interpreted as an sprintf format string.	192	C<$msg> is interpreted as an sprintf format string.
125		193
126	The C<$msg> should not end with C<\n>, but may if that is convenient for	194	The C<$msg> should not end with C<\n>, but may if that is convenient for
…		…
129	Last not least, C<$msg> might be a code reference, in which case it is	197	Last not least, C<$msg> might be a code reference, in which case it is
130	supposed to return the message. It will be called only then the message	198	supposed to return the message. It will be called only then the message
131	actually gets logged, which is useful if it is costly to create the	199	actually gets logged, which is useful if it is costly to create the
132	message in the first place.	200	message in the first place.
133		201
		202	This function takes care of saving and restoring C<$!> and C<$@>, so you
		203	don't have to.
		204
134	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
135	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.
136		210
137	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
138	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
139	need any additional functionality), as those functions will load the	213	need any additional functionality), as those functions will load the
140	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.
…		…
157		231
158	=cut	232	=cut
159		233
160	# also allow syslog equivalent names	234	# also allow syslog equivalent names
161	our %STR2LEVEL = (	235	our %STR2LEVEL = (
162	fatal => 1, emerg => 1,	236	fatal => 1, emerg => 1, exit => 1,
163	alert => 2,	237	alert => 2,
164	critical => 3, crit => 3,	238	critical => 3, crit => 3,
165	error => 4, err => 4,	239	error => 4, err => 4, die => 4,
166	warn => 5, warning => 5,	240	warn => 5, warning => 5,
167	note => 6, notice => 6,	241	note => 6, notice => 6,
168	info => 7,	242	info => 7,
169	debug => 8,	243	debug => 8,
170	trace => 9,	244	trace => 9,
171	);	245	);
172		246
173	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	}
174		259
175	AnyEvent::post_detect {	260	AnyEvent::post_detect {
176	*now = \&AE::now;	261	exact_time $TIME_EXACT;
177	};	262	};
178		263
179	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	264	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
180		265
181	# time, ctx, level, msg	266	# time, ctx, level, msg
…		…
191	}	276	}
192		277
193	join "", @res	278	join "", @res
194	}	279	}
195		280
		281	sub fatal_exit() {
		282	exit 1;
		283	}
		284
196	sub _log {	285	sub _log {
197	my ($ctx, $level, $format, @args) = @_;	286	my ($ctx, $level, $format, @args) = @_;
198		287
199	$level = $level > 0 && $level <= 9	288	$level = $level > 0 && $level <= 9
200	? $level+0	289	? $level+0
201	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	290	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
202		291
203	my $mask = 1 << $level;	292	my $mask = 1 << $level;
204		293
205	my (%seen, @ctx, $now, $fmt);	294	my ($success, %seen, @ctx, $now, @fmt);
206		295
207	do	296	do
208	{	297	{
209	# skip if masked	298	# if !ref, then it's a level number
		299	if (!ref $ctx) {
		300	$level = $ctx;
210	if ($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 = $ctx->[5];
		308	}
		309
		310	# log if log cb
211	if ($ctx->[3]) {	311	if ($ctx->[3]) {
212	# logging target found	312	# logging target found
		313
		314	local ($!, $@);
213		315
214	# now get raw message, unless we have it already	316	# now get raw message, unless we have it already
215	unless ($now) {	317	unless ($now) {
216	$format = $format->() if ref $format;	318	$format = $format->() if ref $format;
217	$format = sprintf $format, @args if @args;	319	$format = sprintf $format, @args if @args;
218	$format =~ s/\n$//;	320	$format =~ s/\n$//;
219	$now = AE::now;	321	$now = _ts;
220	};	322	};
221		323
222	# format msg	324	# format msg
223	my $str = $ctx->[4]	325	my $str = $ctx->[4]
224	? $ctx->[4]($now, $_[0], $level, $format)	326	? $ctx->[4]($now, $_[0], $level, $format)
225	: $fmt \|\|= _format $now, $_[0], $level, $format;	327	: ($fmt[$level] \|\|= _format $now, $_[0], $level, $format);
226		328
		329	$success = 1;
		330
227	$ctx->[3]($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
228	}	335	}
229
230	# not masked, not consumed - propagate to parent contexts
231	push @ctx, values %{ $ctx->[2] };
232	}	336	}
233	}	337	}
234	while $ctx = pop @ctx;	338	while $ctx = pop @ctx;
235		339
236	exit 1 if $level <= 1;	340	fatal_exit if $level <= 1;
		341
		342	$success
237	}	343	}
238		344
239	sub log($$;@) {	345	sub log($$;@) {
240	_log	346	_log
241	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	347	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
242	@_;	348	@_;
243	}	349	}
244		350
245	AnyEvent::log = AE::log = \&log;
246
247	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	351	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
248		352
249	Creates a code reference that, when called, acts as if the	353	Creates a code reference that, when called, acts as if the
250	C<AnyEvent::Log::log> function was called at this point with the givne	354	C<AnyEvent::Log::log> function was called at this point with the given
251	level. C<$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
252	the C<AnyEvent::Log::log> function:	356	the C<AnyEvent::Log::log> function:
253		357
254	my $debug_log = AnyEvent::Log::logger "debug";	358	my $debug_log = AnyEvent::Log::logger "debug";
255		359
…		…
280	# and later in your program	384	# and later in your program
281	$debug_log->("yo, stuff here") if $debug;	385	$debug_log->("yo, stuff here") if $debug;
282		386
283	$debug and $debug_log->("123");	387	$debug and $debug_log->("123");
284		388
285	Note: currently the enabled var is always true - that will be fixed in a
286	future version :)
287
288	=cut	389	=cut
289		390
290	our %LOGGER;	391	our %LOGGER;
291		392
292	# re-assess logging status for all loggers	393	# re-assess logging status for all loggers
293	sub _reassess {	394	sub _reassess {
		395	local $SIG{__DIE__};
		396	my $die = sub { die };
		397
294	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	398	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
295	my ($ctx, $level, $renabled) = @$_;	399	my ($ctx, $level, $renabled) = @$_;
296		400
297	# to detect whether a message would be logged, we # actually	401	# to detect whether a message would be logged, we actually
298	# try to log one and die. this isn't fast, but we can be	402	# try to log one and die. this isn't fast, but we can be
299	# sure that the logging decision is correct :)	403	# sure that the logging decision is correct :)
300		404
301	$$renabled = !eval {	405	$$renabled = !eval {
302	local $SIG{__DIE__};
303
304	_log $ctx, $level, sub { die };	406	_log $ctx, $level, $die;
305		407
306	1	408	1
307	};	409	};
308
309	$$renabled = 1; # TODO
310	}	410	}
311	}	411	}
312		412
313	sub _logger {	413	sub _logger {
314	my ($ctx, $level, $renabled) = @_;	414	my ($ctx, $level, $renabled) = @_;
…		…
319		419
320	$LOGGER{$logger+0} = $logger;	420	$LOGGER{$logger+0} = $logger;
321		421
322	_reassess $logger+0;	422	_reassess $logger+0;
323		423
		424	require AnyEvent::Util unless $AnyEvent::Util::VERSION;
324	my $guard = AnyEvent::Util::guard {	425	my $guard = AnyEvent::Util::guard (sub {
325	# "clean up"	426	# "clean up"
326	delete $LOGGER{$logger+0};	427	delete $LOGGER{$logger+0};
327	};	428	});
328		429
329	sub {	430	sub {
330	$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
331		432
332	_log $ctx, $level, @_	433	_log $ctx, $level, @_
…		…
337	sub logger($;$) {	438	sub logger($;$) {
338	_logger	439	_logger
339	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	440	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
340	@_	441	@_
341	}	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.
342		458
343	=back	459	=back
344		460
345	=head1 LOGGING CONTEXTS	461	=head1 LOGGING CONTEXTS
346		462
…		…
359	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
360	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
361	actually logging the formatted message and telling C<AnyEvent::Log>	477	actually logging the formatted message and telling C<AnyEvent::Log>
362	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).
363		479
364	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
365	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
366	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
367	contexts.	483	contexts.
368		484
369	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
370	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
371	message can arrive at the same context via multiple paths.	487	message can arrive at the same context via multiple paths.
…		…
375	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
376	disabled logging callback and the default formatting callback.	492	disabled logging callback and the default formatting callback.
377		493
378	Package contexts have the package name as logging title by default.	494	Package contexts have the package name as logging title by default.
379		495
380	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
381	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
382	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,	498	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
383	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the	499	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
384	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
385	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
386	C<AnyEvent::Log::Top>.	502	package context is C<$AnyEvent::Log::COLLECT>.
387		503
388	Since perl packages form only an approximate hierarchy, this parent	504	Since perl packages form only an approximate hierarchy, this slave
389	context can of course be removed.	505	context can of course be removed.
390		506
391	All other (anonymous) contexts have no parents and an empty title by	507	All other (anonymous) contexts have no slaves and an empty title by
392	default.	508	default.
393		509
394	When the module is loaded it creates the default context called	510	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
395	C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>),	511	context that simply logs everything via C<warn>, without propagating
396	which simply logs everything via C<warn> and doesn't propagate anything
397	anywhere by default. The purpose of the default context is to provide	512	anything anywhere by default. The purpose of this context is to provide
398	a convenient place to override the global logging target or to attach	513	a convenient place to override the global logging target or to attach
399	additional log targets. It's not meant for filtering.	514	additional log targets. It's not meant for filtering.
400		515
401	It then creates the root context called C<AnyEvent::Log::Root> (also	516	It then creates the C<$AnyEvent::Log::FILTER> context whose
402	stored in C<$AnyEvent::Log::Root>) and sets its log level set to all	517	purpose is to suppress all messages with priority higher
403	levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It	518	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
404	then attached the default logging context to it. The purpose of the root	519	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
405	context is to simply provide filtering according to some global log level.	520	is to simply provide filtering according to some global log level.
406		521
407	Finally it creates the top-level package context called	522	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
408	C<AnyEvent::Log::Top> (also stored in, you might have guessed,	523	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
409	C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
410	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
411	system-wide.	525	messages system-wide.
412		526
413	These three special contexts can also be referred to by the	527	The hierarchy is then:
414	package/context names C<AE::Log::Default>, C<AE::Log::Root> and
415	C<AE::Log::Top>.
416		528
		529	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		530
417	The effect of all this is that log messages, by default, wander up	531	The effect of all this is that log messages, by default, wander up to the
418	to the root context where log messages with lower priority then	532	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		533	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
419	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the	534	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
420	AnyEvent::Log::Default context to be passed to C<warn>.	535	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
421		536
422	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),
423	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
424	other contexts to log, for example, their debug and trace messages to the
425	default target despite the global logging level, or to attach additional	539	messages to the $LOG target despite the global logging level, or to attach
426	log targets that log messages, regardless of the global logging level.	540	additional log targets that log messages, regardless of the global logging
		541	level.
427		542
428	It also makes it easy to replace the default warn-logger by something that	543	It also makes it easy to modify the default warn-logger ($LOG) to
429	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.
430		546
431	=head2 CREATING/FINDING/DESTROYING CONTEXTS	547	=head2 CREATING/FINDING/DESTROYING CONTEXTS
432		548
433	=over 4	549	=over 4
434		550
…		…
456	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	572	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
457	}	573	}
458		574
459	=item AnyEvent::Log::reset	575	=item AnyEvent::Log::reset
460		576
461	Resets all package contexts contexts and recreates the default hierarchy	577	Resets all package contexts and recreates the default hierarchy if
462	if necessary, i.e. resets the logging subsystem to defaults.	578	necessary, i.e. resets the logging subsystem to defaults, as much as
		579	possible. This process keeps references to contexts held by other parts of
		580	the program intact.
463		581
464	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
465	configuration, reset all contexts.	583	configuration, reset all contexts.
466		584
467	Note that this currently destroys all logger callbacks - bug me if you
468	need this fixed :)
469
470	=cut	585	=cut
		586
		587	our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
		588	$AnyEvent::VERBOSE = 9;
471		589
472	sub reset {	590	sub reset {
473	# hard to kill complex data structures	591	# hard to kill complex data structures
474	# we recreate all package loggers and reset the hierarchy	592	# we "recreate" all package loggers and reset the hierarchy
475	while (my ($k, $v) = each %CTX) {	593	while (my ($k, $v) = each %CTX) {
476	@$v = ($k, (1 << 10) - 1 - 1, { });	594	@$v = ($k, (1 << 10) - 1 - 1, { });
477		595
478	my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top";	596	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
479	$v->attach ($CTX{$pkg});
480	}	597	}
481		598
482	$AnyEvent::Log::Default->parents;	599	@$_ = ($_->[0], (1 << 10) - 1 - 1)
483	$AnyEvent::Log::Default->title ("AnyEvent::Log::Default");	600	for $LOG, $FILTER, $COLLECT;
484	$AnyEvent::Log::Default->log_cb (sub {
485	warn shift;
486	0
487	});
488	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
489		601
490	$AnyEvent::Log::Root->parents ($AnyEvent::Log::Default);	602	#$LOG->slaves;
491	$AnyEvent::Log::Root->title ("AnyEvent::Log::Root");	603	$LOG->title ('$AnyEvent::Log::LOG');
492	$AnyEvent::Log::Root->level ($AnyEvent::VERBOSE);	604	$LOG->log_to_warn;
493	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
494		605
495	$AnyEvent::Log::Top->parents ($AnyEvent::Log::Root);	606	$FILTER->slaves ($LOG);
496	$AnyEvent::Log::Top->title ("AnyEvent::Log::Top");	607	$FILTER->title ('$AnyEvent::Log::FILTER');
497	$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');
498		612
499	_reassess;	613	_reassess;
500	}	614	}
501		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
502	# create the default logger contexts	624	# create the default logger contexts
503	$AnyEvent::Log::Default = ctx undef;	625	$LOG = ctx undef;
504	$AnyEvent::Log::Root = ctx undef;	626	$FILTER = ctx undef;
505	$AnyEvent::Log::Top = ctx undef;	627	$COLLECT = ctx undef;
506		628
507	AnyEvent::Log::reset;	629	AnyEvent::Log::reset;
508		630
509	# hello, CPAN, please catch me	631	# hello, CPAN, please catch me
510	package AnyEvent::Log::Default;
511	package AE::Log::Default;
512	package AnyEvent::Log::Root;
513	package AE::Log::Root;
514	package AnyEvent::Log::Top;	632	package AnyEvent::Log::LOG;
515	package AE::Log::Top;	633	package AE::Log::LOG;
		634	package AnyEvent::Log::FILTER;
		635	package AE::Log::FILTER;
		636	package AnyEvent::Log::COLLECT;
		637	package AE::Log::COLLECT;
516		638
517	package AnyEvent::Log::Ctx;	639	package AnyEvent::Log::Ctx;
518
519	# 0 1 2 3 4
520	# [$title, $level, %$parents, &$logcb, &$fmtcb]
521		640
522	=item $ctx = new AnyEvent::Log::Ctx methodname => param...	641	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
523		642
524	This is a convenience constructor that makes it simpler to construct	643	This is a convenience constructor that makes it simpler to construct
525	anonymous logging contexts.	644	anonymous logging contexts.
…		…
528	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
529	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
530	array. The methods are called in the same order as specified.	649	array. The methods are called in the same order as specified.
531		650
532	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
533	level, some parent contexts and a logging callback.	652	level, some slave contexts and a logging callback.
534		653
535	$ctx = new AnyEvent::Log::Ctx	654	$ctx = new AnyEvent::Log::Ctx
536	title => "dubious messages",	655	title => "dubious messages",
537	level => "error",	656	level => "error",
538	log_cb => sub { print STDOUT shift; 0 },	657	log_cb => sub { print STDOUT shift; 0 },
539	parents => [$ctx1, $ctx, $ctx2],	658	slaves => [$ctx1, $ctx, $ctx2],
540	;	659	;
541		660
542	=back	661	=back
543		662
544	=cut	663	=cut
…		…
612	Enables logging for the given levels, leaving all others unchanged.	731	Enables logging for the given levels, leaving all others unchanged.
613		732
614	=item $ctx->disable ($level[, $level...])	733	=item $ctx->disable ($level[, $level...])
615		734
616	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>.
617		758
618	=cut	759	=cut
619		760
620	sub _lvl_lst {	761	sub _lvl_lst {
621	map {	762	map {
…		…
623	: $_ eq "all" ? (1 .. 9)	764	: $_ eq "all" ? (1 .. 9)
624	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"	765	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
625	} @_	766	} @_
626	}	767	}
627		768
		769	sub _lvl {
		770	$_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1]
		771	}
		772
628	our $NOP_CB = sub { 0 };	773	our $NOP_CB = sub { 0 };
629		774
630	sub levels {	775	sub levels {
631	my $ctx = shift;	776	my $ctx = shift;
632	$ctx->[1] = 0;	777	$ctx->[1] = 0;
…		…
635	AnyEvent::Log::_reassess;	780	AnyEvent::Log::_reassess;
636	}	781	}
637		782
638	sub level {	783	sub level {
639	my $ctx = shift;	784	my $ctx = shift;
640	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
641
642	$ctx->[1] = ((1 << $lvl) - 1) << 1;	785	$ctx->[1] = ((1 << &_lvl) - 1) << 1;
643	AnyEvent::Log::_reassess;	786	AnyEvent::Log::_reassess;
644	}	787	}
645		788
646	sub enable {	789	sub enable {
647	my $ctx = shift;	790	my $ctx = shift;
…		…
655	$ctx->[1] &= ~(1 << $_)	798	$ctx->[1] &= ~(1 << $_)
656	for &_lvl_lst;	799	for &_lvl_lst;
657	AnyEvent::Log::_reassess;	800	AnyEvent::Log::_reassess;
658	}	801	}
659		802
		803	sub cap {
		804	my $ctx = shift;
		805	$ctx->[5] = &_lvl;
		806	}
		807
660	=back	808	=back
661		809
662	=head3 PARENT CONTEXTS	810	=head3 SLAVE CONTEXTS
663		811
664	The following methods attach and detach another logging context to a	812	The following methods attach and detach another logging context to a
665	logging context.	813	logging context.
666		814
667	Log messages are propagated to all parent contexts, unless the logging	815	Log messages are propagated to all slave contexts, unless the logging
668	callback consumes the message.	816	callback consumes the message.
669		817
670	=over 4	818	=over 4
671		819
672	=item $ctx->attach ($ctx2[, $ctx3...])	820	=item $ctx->attach ($ctx2[, $ctx3...])
673		821
674	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
675	to add a context twice (the second add will be ignored).	823	to add a context twice (the second add will be ignored).
676		824
677	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.
678		826
679	=item $ctx->detach ($ctx2[, $ctx3...])	827	=item $ctx->detach ($ctx2[, $ctx3...])
680		828
681	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
682	to remove a context that hasn't been added.	830	to remove a context that hasn't been added.
683		831
684	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.
685		833
686	=item $ctx->parents ($ctx2[, $ctx3...])	834	=item $ctx->slaves ($ctx2[, $ctx3...])
687		835
688	Replaces all parents attached to this context by the ones given.	836	Replaces all slaves attached to this context by the ones given.
689		837
690	=cut	838	=cut
691		839
692	sub attach {	840	sub attach {
693	my $ctx = shift;	841	my $ctx = shift;
…		…
701		849
702	delete $ctx->[2]{$_+0}	850	delete $ctx->[2]{$_+0}
703	for map { AnyEvent::Log::ctx $_ } @_;	851	for map { AnyEvent::Log::ctx $_ } @_;
704	}	852	}
705		853
706	sub parents {	854	sub slaves {
707	undef $_[0][2];	855	undef $_[0][2];
708	&attach;	856	&attach;
709	}	857	}
710		858
711	=back	859	=back
712		860
713	=head3 MESSAGE LOGGING	861	=head3 LOG TARGETS
714		862
715	The following methods configure how the logging context actually does	863	The following methods configure how the logging context actually does
716	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
717	whatever it wants to do with it) and also allows you to log messages	865	whatever it wants to do with it).
718	directly to a context, without going via your package context.
719		866
720	=over 4	867	=over 4
721		868
722	=item $ctx->log_cb ($cb->($str))	869	=item $ctx->log_cb ($cb->($str)
723		870
724	Replaces the logging callback on the context (C<undef> disables the	871	Replaces the logging callback on the context (C<undef> disables the
725	logging callback).	872	logging callback).
726		873
727	The logging callback is responsible for handling formatted log messages	874	The logging callback is responsible for handling formatted log messages
728	(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
729	newline (and are possibly multiline themselves).	876	newline (and are possibly multiline themselves).
730		877
731	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
732	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
733	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.
734		881
735	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
736	and do not consume it.	883	and do not consume it.
737		884
738	$ctx->log_cb (sub { print STDERR shift; 0 });	885	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
746	your program.	893	your program.
747		894
748	$ctx->levels ("debug", "trace");	895	$ctx->levels ("debug", "trace");
749	$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
750		897
751	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	898	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
752		899
753	Replaces the formatting callback on the context (C<undef> restores the	900	Replaces the formatting callback on the context (C<undef> restores the
754	default formatter).	901	default formatter).
755		902
756	The callback is passed the (possibly fractional) timestamp, the original	903	The callback is passed the (possibly fractional) timestamp, the original
757	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
758	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
759	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.
760		912
761	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
762	brackets.	914	brackets.
763		915
764	$ctx->fmt_cb (sub {	916	$ctx->fmt_cb (sub {
…		…
766		918
767	"<$lvl>$msg\n"	919	"<$lvl>$msg\n"
768	});	920	});
769		921
770	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
771	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.
772		924
773	$ctx->fmt_cb (sub { \@_ });	925	$ctx->fmt_cb (sub { \@_ });
774	$ctx->log_cb (sub {	926	$ctx->log_cb (sub {
775	my ($msg) = @_;	927	my ($msg) = @_;
776		928
…		…
781	"$msg->[3]";	933	"$msg->[3]";
782		934
783	0	935	0
784	});	936	});
785		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, $str] as input.
		966
786	=cut	967	=cut
787		968
788	sub log_cb {	969	sub log_cb {
789	my ($ctx, $cb) = @_;	970	my ($ctx, $cb) = @_;
790		971
…		…
795	my ($ctx, $cb) = @_;	976	my ($ctx, $cb) = @_;
796		977
797	$ctx->[4] = $cb;	978	$ctx->[4] = $cb;
798	}	979	}
799		980
800	=item $ctx->log ($level, $msg[, @params])	981	sub log_to_warn {
		982	my ($ctx, $path) = @_;
801		983
802	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	}
803		989
804	=item $logger = $ctx->logger ($level[, \$enabled])	990	sub log_to_file {
805		991	my ($ctx, $path) = @_;
806	Same as C<AnyEvent::Log::logger>, but uses the given context as log
807	context.
808
809	=cut
810
811	*log = \&AnyEvent::Log::_log;
812	*logger = \&AnyEvent::Log::_logger;
813
814	1;
815
816	=back
817
818	=head1 EXAMPLES
819
820	This section shows some common configurations.
821
822	=over 4
823
824	=item Setting the global logging level.
825
826	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
827	running your program, or modify the log level of the root context:
828
829	PERL_ANYEVENT_VERBOSE=5 ./myprog
830
831	$AnyEvent::Log::Root->level ("warn");
832
833	=item Append all messages to a file instead of sending them to STDERR.
834
835	This is affected by the global logging level.
836		992
837	open my $fh, ">>", $path	993	open my $fh, ">>", $path
838	or die "$path: $!";	994	or die "$path: $!";
839		995
840	$AnyEvent::Log::Default->log_cb (sub {	996	$ctx->log_cb (sub {
841	syswrite $fh, shift;	997	syswrite $fh, shift;
842	0	998	0
843	});	999	});
		1000	}
		1001
		1002	sub log_to_path {
		1003	my ($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	=head1 EXAMPLES
		1298
		1299	This section shows some common configurations, both as code, and as
		1300	C<PERL_ANYEVENT_LOG> string.
		1301
		1302	=over 4
		1303
		1304	=item Setting the global logging level.
		1305
		1306	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1307	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1308	the root context at runtime:
		1309
		1310	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1311
		1312	PERL_ANYEVENT_LOG=log=warn
		1313
		1314	$AnyEvent::Log::FILTER->level ("warn");
		1315
		1316	=item Append all messages to a file instead of sending them to STDERR.
		1317
		1318	This is affected by the global logging level.
		1319
		1320	$AnyEvent::Log::LOG->log_to_file ($path);
		1321
		1322	PERL_ANYEVENT_LOG=log=file=/some/path
844		1323
845	=item Write all messages with priority C<error> and higher to a file.	1324	=item Write all messages with priority C<error> and higher to a file.
846		1325
847	This writes them only when the global logging level allows it, because	1326	This writes them only when the global logging level allows it, because
848	it is attached to the default context which is invoked I<after> global	1327	it is attached to the default context which is invoked I<after> global
849	filtering.	1328	filtering.
850		1329
851	open my $fh, ">>", $path	1330	$AnyEvent::Log::FILTER->attach (
852	or die "$path: $!";	1331	new AnyEvent::Log::Ctx log_to_file => $path);
853		1332
854	$AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx	1333	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
855	log_cb => sub { syswrite $fh, shift; 0 });
856		1334
857	This writes them regardless of the global logging level, because it is	1335	This writes them regardless of the global logging level, because it is
858	attached to the toplevel context, which receives all messages I<before>	1336	attached to the toplevel context, which receives all messages I<before>
859	the global filtering.	1337	the global filtering.
860		1338
861	$AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx	1339	$AnyEvent::Log::COLLECT->attach (
862	log_cb => sub { syswrite $fh, shift; 0 });	1340	new AnyEvent::Log::Ctx log_to_file => $path);
863		1341
		1342	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1343
864	In both cases, messages are still written to STDOUT.	1344	In both cases, messages are still written to STDERR.
		1345
		1346	=item Additionally log all messages with C<warn> and higher priority to
		1347	C<syslog>, but cap at C<error>.
		1348
		1349	This logs all messages to the default log target, but also logs messages
		1350	with priority C<warn> or higher (and not filtered otherwise) to syslog
		1351	facility C<user>. Messages with priority higher than C<error> will be
		1352	logged with level C<error>.
		1353
		1354	$AnyEvent::Log::LOG->attach (
		1355	new AnyEvent::Log::Ctx
		1356	level => "warn",
		1357	cap => "error",
		1358	syslog => "user",
		1359	);
		1360
		1361	PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
865		1362
866	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).	1363	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
867		1364
868	Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug>	1365	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
869	context and increase the C<AnyEvent::Debug> logging level - this simply
870	circumvents the global filtering for trace messages.	1366	context - this simply circumvents the global filtering for trace messages.
871		1367
872	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;	1368	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
873	$debug->attach ($AnyEvent::Log::Default);	1369	$debug->attach ($AnyEvent::Log::LOG);
874	$debug->levels ("trace"); # not "level"!
875		1370
876	This of course works for any package.	1371	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1372
		1373	This of course works for any package, not just L<AnyEvent::Debug>, but
		1374	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1375	default.
877		1376
878	=back	1377	=back
879		1378
880	=head1 AUTHOR	1379	=head1 AUTHOR
881		1380
882	Marc Lehmann <schmorp@schmorp.de>	1381	Marc Lehmann <schmorp@schmorp.de>
883	http://home.schmorp.de/	1382	http://home.schmorp.de/
884		1383
885	=cut	1384	=cut
		1385
		1386	1
		1387

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.15 by root, Sat Aug 20 02:16:59 2011 UTC vs. Revision 1.53 by root, Tue Mar 27 16:21:11 2012 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.15 by root, Sat Aug 20 02:16:59 2011 UTC vs.
Revision 1.53 by root, Tue Mar 27 16:21:11 2012 UTC