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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs.
Revision 1.40 by root, Fri Aug 26 16:18:01 2011 UTC

…		…
2		2
3	AnyEvent::Log - simple logging "framework"	3	AnyEvent::Log - simple logging "framework"
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	# simple use	7	Simple uses:
		8
8	use AnyEvent;	9	use AnyEvent;
9		10
10	AE::log debug => "hit my knee";	11	AE::log debug => "hit my knee";
11	AE::log warn => "it's a bit too hot";	12	AE::log warn => "it's a bit too hot";
12	AE::log error => "the flag was false!";	13	AE::log error => "the flag was false!";
13	AE::log fatal => "the bit toggled! run!";	14	AE::log fatal => "the bit toggled! run!"; # never returns
14		15
15	# "complex" use	16	"Complex" uses (for speed sensitive code):
		17
16	use AnyEvent::Log;	18	use AnyEvent::Log;
17		19
18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;	20	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19		21
20	$tracer->("i am here") if $trace;	22	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	23	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		24
23	# configuration	25	Configuration (also look at the EXAMPLES section):
24		26
25	# set logging for this package to maximum	27	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("all");	28	AnyEvent::Log::ctx->level ("error");
27		29
28	# set logging globally to anything below debug	30	# set logging level to suppress anything below "notice"
29	(AnyEvent::Log::ctx "")->level ("notice");	31	$AnyEvent::Log::FILTER->level ("notice");
30		32
31	# see also EXAMPLES, below	33	# send all critical and higher priority messages to syslog,
32		34	# regardless of (most) other settings
33	# disable logging for package "AnyEvent" and all packages below it	35	$AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
34	AnyEvent->AnyEvent::Log::ctx->level (0);	36	level => "critical",
35		37	log_to_syslog => "user",
36	# log everything below debug to a file, for the whole program	38	);
37	my $ctx = AnyEvent::Log::ctx;
38	$ctx->log_cb (sub { print FILE shift; 0 });
39	(AnyEvent::Log::ctx "")->add ($ctx);
40		39
41	=head1 DESCRIPTION	40	=head1 DESCRIPTION
42		41
43	This module implements a relatively simple "logging framework". It doesn't	42	This module implements a relatively simple "logging framework". It doesn't
44	attempt to be "the" logging solution or even "a" logging solution for	43	attempt to be "the" logging solution or even "a" logging solution for
45	AnyEvent - AnyEvent simply creates logging messages internally, and this	44	AnyEvent - AnyEvent simply creates logging messages internally, and this
46	module more or less exposes the mechanism, with some extra spiff to allow	45	module more or less exposes the mechanism, with some extra spiff to allow
47	using it from other modules as well.	46	using it from other modules as well.
48		47
49	Remember that the default verbosity level is C<0>, so nothing will be	48	Remember that the default verbosity level is C<0> (C<off>), so nothing
50	logged, ever, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number	49	will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
51	before starting your program, or change the logging level at runtime wiht	50	before starting your program, or change the logging level at runtime with
52	something like:	51	something like:
53		52
54	use AnyEvent;	53	use AnyEvent::Log;
55	(AnyEvent::Log::ctx "")->level ("info");	54	$AnyEvent::Log::FILTER->level ("info");
56		55
57	The design goal behind this module was to keep it simple (and small),	56	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	57	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	58	extensive enough for the most common tasks, such as logging to multiple
60	targets, or being able to log into a database.	59	targets, or being able to log into a database.
61		60
		61	The module is also usable before AnyEvent itself is initialised, in which
		62	case some of the functionality might be reduced.
		63
		64	The amount of documentation might indicate otherwise, but the runtime part
		65	of the module is still just below 300 lines of code.
		66
		67	=head1 LOGGING LEVELS
		68
		69	Logging levels in this module range from C<1> (highest priority) to C<9>
		70	(lowest priority). Note that the lowest numerical value is the highest
		71	priority, so when this document says "higher priority" it means "lower
		72	numerical value".
		73
		74	Instead of specifying levels by name you can also specify them by aliases:
		75
		76	LVL NAME SYSLOG PERL NOTE
		77	1 fatal emerg exit aborts program!
		78	2 alert
		79	3 critical crit
		80	4 error err die
		81	5 warn warning
		82	6 note notice
		83	7 info
		84	8 debug
		85	9 trace
		86
		87	As you can see, some logging levels have multiple aliases - the first one
		88	is the "official" name, the second one the "syslog" name (if it differs)
		89	and the third one the "perl" name, suggesting that you log C<die> messages
		90	at C<error> priority.
		91
		92	You can normally only log a single message at highest priority level
		93	(C<1>, C<fatal>), because logging a fatal message will also quit the
		94	program - so use it sparingly :)
		95
		96	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		97	or C<all> - these are only valid in the methods they are documented for.
		98
62	=head1 LOGGING FUNCTIONS	99	=head1 LOGGING FUNCTIONS
63		100
64	These functions allow you to log messages. They always use the caller's	101	These functions allow you to log messages. They always use the caller's
65	package as a "logging module/source". Also, the main logging function is	102	package as a "logging context". Also, the main logging function C<log> is
66	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	103	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
67	loaded.	104	loaded.
68		105
69	=over 4	106	=over 4
70		107
…		…
74		111
75	use Carp ();	112	use Carp ();
76	use POSIX ();	113	use POSIX ();
77		114
78	use AnyEvent (); BEGIN { AnyEvent::common_sense }	115	use AnyEvent (); BEGIN { AnyEvent::common_sense }
79	use AnyEvent::Util ();	116	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
		117
		118	our $VERSION = $AnyEvent::VERSION;
		119
		120	our ($COLLECT, $FILTER, $LOG);
80		121
81	our ($now_int, $now_str1, $now_str2);	122	our ($now_int, $now_str1, $now_str2);
82		123
83	# Format Time, not public - yet?	124	# Format Time, not public - yet?
84	sub ft($) {	125	sub ft($) {
…		…
89	if $now_int != $i;	130	if $now_int != $i;
90		131
91	"$now_str1$f$now_str2"	132	"$now_str1$f$now_str2"
92	}	133	}
93		134
94	our %CTX; # all logging contexts	135	our %CTX; # all package contexts
95		136
96	# creates a default package context object for the given package	137	# creates a default package context object for the given package
97	sub _pkg_ctx($) {	138	sub _pkg_ctx($) {
98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	139	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
99		140
100	# link "parent" package	141	# link "parent" package
101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "";	142	my $parent = $_[0] =~ /^(.+)::/
		143	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		144	: $COLLECT;
102		145
103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
104	$ctx->[2]{$pkg+0} = $pkg;	146	$ctx->[2]{$parent+0} = $parent;
105		147
106	$ctx	148	$ctx
107	}	149	}
108		150
109	=item AnyEvent::Log::log $level, $msg[, @args]	151	=item AnyEvent::Log::log $level, $msg[, @args]
110		152
111	Requests logging of the given C<$msg> with the given log level (1..9).	153	Requests logging of the given C<$msg> with the given log level, and
112	You can also use the following strings as log level: C<fatal> (1),	154	returns true if the message was logged I<somewhere>.
113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114	C<info> (7), C<debug> (8), C<trace> (9).
115		155
116	For C<fatal> log levels, the program will abort.	156	For C<fatal> log levels, the program will abort.
117		157
118	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	158	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
119	C<$msg> is interpreted as an sprintf format string.	159	C<$msg> is interpreted as an sprintf format string.
…		…
125	supposed to return the message. It will be called only then the message	165	supposed to return the message. It will be called only then the message
126	actually gets logged, which is useful if it is costly to create the	166	actually gets logged, which is useful if it is costly to create the
127	message in the first place.	167	message in the first place.
128		168
129	Whether the given message will be logged depends on the maximum log level	169	Whether the given message will be logged depends on the maximum log level
130	and the caller's package.	170	and the caller's package. The return value can be used to ensure that
		171	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		172	runtime error it tries to log it at C<die> level, but if that message is
		173	lost it simply uses warn.
131		174
132	Note that you can (and should) call this function as C<AnyEvent::log> or	175	Note that you can (and should) call this function as C<AnyEvent::log> or
133	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	176	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
134	need any additional functionality), as those functions will load the	177	need any additional functionality), as those functions will load the
135	logging module on demand only. They are also much shorter to write.	178	logging module on demand only. They are also much shorter to write.
136		179
137	Also, if you otpionally generate a lot of debug messages (such as when	180	Also, if you optionally generate a lot of debug messages (such as when
138	tracing some code), you should look into using a logger callback and a	181	tracing some code), you should look into using a logger callback and a
139	boolean enabler (see C<logger>, below).	182	boolean enabler (see C<logger>, below).
140		183
141	Example: log something at error level.	184	Example: log something at error level.
142		185
…		…
152		195
153	=cut	196	=cut
154		197
155	# also allow syslog equivalent names	198	# also allow syslog equivalent names
156	our %STR2LEVEL = (	199	our %STR2LEVEL = (
157	fatal => 1, emerg => 1,	200	fatal => 1, emerg => 1, exit => 1,
158	alert => 2,	201	alert => 2,
159	critical => 3, crit => 3,	202	critical => 3, crit => 3,
160	error => 4, err => 4,	203	error => 4, err => 4, die => 4,
161	warn => 5, warning => 5,	204	warn => 5, warning => 5,
162	note => 6, notice => 6,	205	note => 6, notice => 6,
163	info => 7,	206	info => 7,
164	debug => 8,	207	debug => 8,
165	trace => 9,	208	trace => 9,
166	);	209	);
167		210
168	sub now () { time }	211	our $TIME_EXACT;
		212
		213	sub exact_time($) {
		214	$TIME_EXACT = shift;
		215	*_ts = $AnyEvent::MODEL
		216	? $TIME_EXACT ? \&AE::now : \&AE::time
		217	: sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
		218	}
		219
		220	BEGIN {
		221	exact_time 0;
		222	}
169		223
170	AnyEvent::post_detect {	224	AnyEvent::post_detect {
171	*now = \&AE::now;	225	exact_time $TIME_EXACT;
172	};	226	};
173		227
174	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	228	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
175		229
176	# time, ctx, level, msg	230	# time, ctx, level, msg
177	sub _format($$$$) {	231	sub _format($$$$) {
178	my $pfx = ft $_[0];	232	my $ts = ft $_[0];
		233	my $ct = " ";
		234
179	my @res;	235	my @res;
180		236
181	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {	237	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
182	push @res, "$pfx $_\n";	238	push @res, "$ts$ct$_\n";
183	$pfx = "\t";	239	$ct = " + ";
184	}	240	}
185		241
186	join "", @res	242	join "", @res
187	}	243	}
188		244
189	sub _log {	245	sub _log {
190	my ($ctx, $level, $format, @args) = @_;	246	my ($ctx, $level, $format, @args) = @_;
191		247
		248	$level = $level > 0 && $level <= 9
		249	? $level+0
192	$level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	250	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
193		251
194	my $mask = 1 << $level;	252	my $mask = 1 << $level;
195		253
196	my (@ctx, $now, $fmt);	254	my ($success, %seen, @ctx, $now, $fmt);
197		255
198	do {	256	do
		257	{
199	# skip if masked	258	# skip if masked
200	next unless $ctx->[1] & $mask;	259	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
201
202	if ($ctx->[3]) {	260	if ($ctx->[3]) {
203	# logging target found	261	# logging target found
204		262
205	# now get raw message, unless we have it already	263	# now get raw message, unless we have it already
206	unless ($now) {	264	unless ($now) {
207	$format = $format->() if ref $format;	265	$format = $format->() if ref $format;
208	$format = sprintf $format, @args if @args;	266	$format = sprintf $format, @args if @args;
209	$format =~ s/\n$//;	267	$format =~ s/\n$//;
210	$now = AE::now;	268	$now = _ts;
		269	};
		270
		271	# format msg
		272	my $str = $ctx->[4]
		273	? $ctx->[4]($now, $_[0], $level, $format)
		274	: ($fmt \|\|= _format $now, $_[0], $level, $format);
		275
		276	$success = 1;
		277
		278	$ctx->[3]($str)
		279	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		280	} else {
		281	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		282	}
211	};	283	}
212
213	# format msg
214	my $str = $ctx->[4]
215	? $ctx->[4]($now, $_[0], $level, $format)
216	: $fmt \|\|= _format $now, $_[0], $level, $format;
217
218	$ctx->[3]($str)
219	and next;
220	}	284	}
221
222	# not masked, not consume - propagate to parent contexts
223	push @ctx, values %{ $ctx->[2] };
224	} while $ctx = pop @ctx;	285	while $ctx = pop @ctx;
225		286
226	exit 1 if $level <= 1;	287	exit 1 if $level <= 1;
		288
		289	$success
227	}	290	}
228		291
229	sub log($$;@) {	292	sub log($$;@) {
230	_log	293	_log
231	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	294	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
…		…
235	AnyEvent::log = AE::log = \&log;	298	AnyEvent::log = AE::log = \&log;
236		299
237	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	300	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
238		301
239	Creates a code reference that, when called, acts as if the	302	Creates a code reference that, when called, acts as if the
240	C<AnyEvent::Log::log> function was called at this point with the givne	303	C<AnyEvent::Log::log> function was called at this point with the given
241	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	304	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
242	the C<AnyEvent::Log::log> function:	305	the C<AnyEvent::Log::log> function:
243		306
244	my $debug_log = AnyEvent::Log::logger "debug";	307	my $debug_log = AnyEvent::Log::logger "debug";
245		308
…		…
270	# and later in your program	333	# and later in your program
271	$debug_log->("yo, stuff here") if $debug;	334	$debug_log->("yo, stuff here") if $debug;
272		335
273	$debug and $debug_log->("123");	336	$debug and $debug_log->("123");
274		337
275	Note: currently the enabled var is always true - that will be fixed in a
276	future version :)
277
278	=cut	338	=cut
279		339
280	our %LOGGER;	340	our %LOGGER;
281		341
282	# re-assess logging status for all loggers	342	# re-assess logging status for all loggers
283	sub _reassess {	343	sub _reassess {
		344	local $SIG{__DIE__};
		345	my $die = sub { die };
		346
284	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	347	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
285	my ($ctx, $level, $renabled) = @$_;	348	my ($ctx, $level, $renabled) = @$_;
286		349
287	# to detetc whether a message would be logged, we # actually	350	# to detect whether a message would be logged, we actually
288	# try to log one and die. this isn't # fast, but we can be	351	# try to log one and die. this isn't fast, but we can be
289	# sure that the logging decision is correct :)	352	# sure that the logging decision is correct :)
290		353
291	$$renabled = !eval {	354	$$renabled = !eval {
292	local $SIG{__DIE__};
293
294	_log $ctx, $level, sub { die };	355	_log $ctx, $level, $die;
295		356
296	1	357	1
297	};	358	};
298
299	$$renabled = 1; # TODO
300	}	359	}
301	}	360	}
302		361
303	sub _logger($;$) {	362	sub _logger {
304	my ($ctx, $level, $renabled) = @_;	363	my ($ctx, $level, $renabled) = @_;
305		364
306	$renabled \|\|= \my $enabled;
307
308	$$renabled = 1;	365	$$renabled = 1;
309		366
310	my $logger = [$ctx, $level, $renabled];	367	my $logger = [$ctx, $level, $renabled];
311		368
312	$LOGGER{$logger+0} = $logger;	369	$LOGGER{$logger+0} = $logger;
313		370
314	_reassess $logger+0;	371	_reassess $logger+0;
315		372
		373	require AnyEvent::Util;
316	my $guard = AnyEvent::Util::guard {	374	my $guard = AnyEvent::Util::guard (sub {
317	# "clean up"	375	# "clean up"
318	delete $LOGGER{$logger+0};	376	delete $LOGGER{$logger+0};
319	};	377	});
320		378
321	sub {	379	sub {
322	$guard if 0; # keep guard alive, but don't cause runtime overhead	380	$guard if 0; # keep guard alive, but don't cause runtime overhead
323		381
324	_log $ctx, $level, @_	382	_log $ctx, $level, @_
…		…
329	sub logger($;$) {	387	sub logger($;$) {
330	_logger	388	_logger
331	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	389	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
332	@_	390	@_
333	}	391	}
		392
		393	=item AnyEvent::Log::exact_time $on
		394
		395	By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
		396	eventloop time, for the log timestamps. After calling this function with a
		397	true value it will instead resort to C<AE::time>, i.e. fetch the current
		398	time on each log message. This only makes a difference for event loops
		399	that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
		400
		401	This setting can be changed at any time by calling this function.
		402
		403	Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
		404	initialised, this switch will also decide whether to use C<CORE::time> or
		405	C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
		406	available.
334		407
335	=back	408	=back
336		409
337	=head1 LOGGING CONTEXTS	410	=head1 LOGGING CONTEXTS
338		411
…		…
351	timestamp, context, level and string message and formats it in the way	424	timestamp, context, level and string message and formats it in the way
352	it should be logged) and a logging callback (which is responsible for	425	it should be logged) and a logging callback (which is responsible for
353	actually logging the formatted message and telling C<AnyEvent::Log>	426	actually logging the formatted message and telling C<AnyEvent::Log>
354	whether it has consumed the message, or whether it should be propagated).	427	whether it has consumed the message, or whether it should be propagated).
355		428
356	For propagation, a context can have any number of attached I<parent	429	For propagation, a context can have any number of attached I<slave
357	contexts>. Any message that is neither masked by the logging mask nor	430	contexts>. Any message that is neither masked by the logging mask nor
358	masked by the logging callback returning true will be passed to all parent	431	masked by the logging callback returning true will be passed to all slave
359	contexts.	432	contexts.
		433
		434	Each call to a logging function will log the message at most once per
		435	context, so it does not matter (much) if there are cycles or if the
		436	message can arrive at the same context via multiple paths.
360		437
361	=head2 DEFAULTS	438	=head2 DEFAULTS
362		439
363	By default, all logging contexts have an full set of log levels ("all"), a	440	By default, all logging contexts have an full set of log levels ("all"), a
364	disabled logging callback and the default formatting callback.	441	disabled logging callback and the default formatting callback.
365		442
366	Package contexts have the package name as logging title by default.	443	Package contexts have the package name as logging title by default.
367		444
368	They have exactly one parent - the context of the "parent" package. The	445	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	446	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>,	447	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371	and C<AnyEvent> becomes the empty string.	448	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		449	exception of the rule - just like the "parent" of any single-component
		450	package name in Perl is C<main>, the default slave of any top-level
		451	package context is C<$AnyEvent::Log::COLLECT>.
372		452
373	Since perl packages form only an approximate hierarchy, this parent	453	Since perl packages form only an approximate hierarchy, this slave
374	context can of course be removed.	454	context can of course be removed.
375		455
376	All other (anonymous) contexts have no parents and an empty title by	456	All other (anonymous) contexts have no slaves and an empty title by
377	default.	457	default.
378		458
379	When the module is first loaded, it configures the root context (the one	459	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
380	with the empty string) to simply dump all log messages to C<STDERR>,	460	context that simply logs everything via C<warn>, without propagating
381	and sets it's log level set to all levels up to the one specified by	461	anything anywhere by default. The purpose of this context is to provide
382	C<$ENV{PERL_ANYEVENT_VERBOSE}>.	462	a convenient place to override the global logging target or to attach
		463	additional log targets. It's not meant for filtering.
		464
		465	It then creates the C<$AnyEvent::Log::FILTER> context whose
		466	purpose is to suppress all messages with priority higher
		467	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		468	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		469	is to simply provide filtering according to some global log level.
		470
		471	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		472	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		473	leaves it at default config. Its purpose is simply to collect all log
		474	messages system-wide.
		475
		476	The hierarchy is then:
		477
		478	any package, eventually -> $COLLECT -> $FILTER -> $LOG
383		479
384	The effect of all this is that log messages, by default, wander up to the	480	The effect of all this is that log messages, by default, wander up to the
385	root context and will be logged to STDERR if their log level is less than	481	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
386	or equal to C<$ENV{PERL_ANYEVENT_VERBOSE}>.	482	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		483	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		484	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
387		485
		486	This makes it easy to set a global logging level (by modifying $FILTER),
		487	but still allow other contexts to send, for example, their debug and trace
		488	messages to the $LOG target despite the global logging level, or to attach
		489	additional log targets that log messages, regardless of the global logging
		490	level.
		491
		492	It also makes it easy to modify the default warn-logger ($LOG) to
		493	something that logs to a file, or to attach additional logging targets
		494	(such as loggign to a file) by attaching it to $FILTER.
		495
388	=head2 CREATING/FINDING A CONTEXT	496	=head2 CREATING/FINDING/DESTROYING CONTEXTS
389		497
390	=over 4	498	=over 4
391		499
392	=item $ctx = AnyEvent::Log::ctx [$pkg]	500	=item $ctx = AnyEvent::Log::ctx [$pkg]
393		501
…		…
411	: defined $pkg	519	: defined $pkg
412	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg	520	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
413	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	521	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
414	}	522	}
415		523
416	# create default root context	524	=item AnyEvent::Log::reset
417	{	525
418	my $root = ctx undef;	526	Resets all package contexts and recreates the default hierarchy if
419	$root->[0] = "";	527	necessary, i.e. resets the logging subsystem to defaults, as much as
420	$root->title ("default");	528	possible. This process keeps references to contexts held by other parts of
421	$root->level ($AnyEvent::VERBOSE); undef $AnyEvent::VERBOSE;	529	the program intact.
422	$root->log_cb (sub {	530
423	print STDERR shift;	531	This can be used to implement config-file (re-)loading: before loading a
424	0	532	configuration, reset all contexts.
		533
		534	=cut
		535
		536	sub reset {
		537	# hard to kill complex data structures
		538	# we "recreate" all package loggers and reset the hierarchy
		539	while (my ($k, $v) = each %CTX) {
		540	@$v = ($k, (1 << 10) - 1 - 1, { });
		541
		542	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
425	});	543	}
426	$CTX{""} = $root;	544
		545	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		546	for $LOG, $FILTER, $COLLECT;
		547
		548	#$LOG->slaves;
		549	$LOG->title ('$AnyEvent::Log::LOG');
		550	$LOG->log_to_warn;
		551
		552	$FILTER->slaves ($LOG);
		553	$FILTER->title ('$AnyEvent::Log::FILTER');
		554	$FILTER->level ($AnyEvent::VERBOSE);
		555
		556	$COLLECT->slaves ($FILTER);
		557	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		558
		559	_reassess;
427	}	560	}
		561
		562	# create the default logger contexts
		563	$LOG = ctx undef;
		564	$FILTER = ctx undef;
		565	$COLLECT = ctx undef;
		566
		567	AnyEvent::Log::reset;
		568
		569	# hello, CPAN, please catch me
		570	package AnyEvent::Log::LOG;
		571	package AE::Log::LOG;
		572	package AnyEvent::Log::FILTER;
		573	package AE::Log::FILTER;
		574	package AnyEvent::Log::COLLECT;
		575	package AE::Log::COLLECT;
		576
		577	package AnyEvent::Log::Ctx;
		578
		579	# 0 1 2 3 4
		580	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		581
		582	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		583
		584	This is a convenience constructor that makes it simpler to construct
		585	anonymous logging contexts.
		586
		587	Each key-value pair results in an invocation of the method of the same
		588	name as the key with the value as parameter, unless the value is an
		589	arrayref, in which case it calls the method with the contents of the
		590	array. The methods are called in the same order as specified.
		591
		592	Example: create a new logging context and set both the default logging
		593	level, some slave contexts and a logging callback.
		594
		595	$ctx = new AnyEvent::Log::Ctx
		596	title => "dubious messages",
		597	level => "error",
		598	log_cb => sub { print STDOUT shift; 0 },
		599	slaves => [$ctx1, $ctx, $ctx2],
		600	;
428		601
429	=back	602	=back
430		603
431	=cut	604	=cut
432		605
433	package AnyEvent::Log::Ctx;	606	sub new {
		607	my $class = shift;
434		608
435	# 0 1 2 3 4	609	my $ctx = AnyEvent::Log::ctx undef;
436	# [$title, $level, %$parents, &$logcb, &$fmtcb]	610
		611	while (@_) {
		612	my ($k, $v) = splice @_, 0, 2;
		613	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		614	}
		615
		616	bless $ctx, $class # do we really support subclassing, hmm?
		617	}
		618
437		619
438	=head2 CONFIGURING A LOG CONTEXT	620	=head2 CONFIGURING A LOG CONTEXT
439		621
440	The following methods can be used to configure the logging context.	622	The following methods can be used to configure the logging context.
441		623
…		…
535	AnyEvent::Log::_reassess;	717	AnyEvent::Log::_reassess;
536	}	718	}
537		719
538	=back	720	=back
539		721
540	=head3 PARENT CONTEXTS	722	=head3 SLAVE CONTEXTS
541		723
542	The following methods attach and detach another logging context to a	724	The following methods attach and detach another logging context to a
543	logging context.	725	logging context.
544		726
545	Log messages are propagated to all parent contexts, unless the logging	727	Log messages are propagated to all slave contexts, unless the logging
546	callback consumes the message.	728	callback consumes the message.
547		729
548	=over 4	730	=over 4
549		731
550	=item $ctx->attach ($ctx2[, $ctx3...])	732	=item $ctx->attach ($ctx2[, $ctx3...])
551		733
552	Attaches the given contexts as parents to this context. It is not an error	734	Attaches the given contexts as slaves to this context. It is not an error
553	to add a context twice (the second add will be ignored).	735	to add a context twice (the second add will be ignored).
554		736
555	A context can be specified either as package name or as a context object.	737	A context can be specified either as package name or as a context object.
556		738
557	=item $ctx->detach ($ctx2[, $ctx3...])	739	=item $ctx->detach ($ctx2[, $ctx3...])
558		740
559	Removes the given parents from this context - it's not an error to attempt	741	Removes the given slaves from this context - it's not an error to attempt
560	to remove a context that hasn't been added.	742	to remove a context that hasn't been added.
561		743
562	A context can be specified either as package name or as a context object.	744	A context can be specified either as package name or as a context object.
		745
		746	=item $ctx->slaves ($ctx2[, $ctx3...])
		747
		748	Replaces all slaves attached to this context by the ones given.
563		749
564	=cut	750	=cut
565		751
566	sub attach {	752	sub attach {
567	my $ctx = shift;	753	my $ctx = shift;
…		…
575		761
576	delete $ctx->[2]{$_+0}	762	delete $ctx->[2]{$_+0}
577	for map { AnyEvent::Log::ctx $_ } @_;	763	for map { AnyEvent::Log::ctx $_ } @_;
578	}	764	}
579		765
		766	sub slaves {
		767	undef $_[0][2];
		768	&attach;
		769	}
		770
580	=back	771	=back
581		772
582	=head3 MESSAGE LOGGING	773	=head3 LOG TARGETS
583		774
584	The following methods configure how the logging context actually does	775	The following methods configure how the logging context actually does
585	the logging (which consists of formatting the message and printing it or	776	the logging (which consists of formatting the message and printing it or
586	whatever it wants to do with it) and also allows you to log messages	777	whatever it wants to do with it).
587	directly to a context, without going via your package context.
588		778
589	=over 4	779	=over 4
590		780
591	=item $ctx->log_cb ($cb->($str))	781	=item $ctx->log_cb ($cb->($str)
592		782
593	Replaces the logging callback on the context (C<undef> disables the	783	Replaces the logging callback on the context (C<undef> disables the
594	logging callback).	784	logging callback).
595		785
596	The logging callback is responsible for handling formatted log messages	786	The logging callback is responsible for handling formatted log messages
597	(see C<fmt_cb> below) - normally simple text strings that end with a	787	(see C<fmt_cb> below) - normally simple text strings that end with a
598	newline (and are possibly multiline themselves).	788	newline (and are possibly multiline themselves).
599		789
600	It also has to return true iff it has consumed the log message, and false	790	It also has to return true iff it has consumed the log message, and false
601	if it hasn't. Consuming a message means that it will not be sent to any	791	if it hasn't. Consuming a message means that it will not be sent to any
602	parent context. When in doubt, return C<0> from your logging callback.	792	slave context. When in doubt, return C<0> from your logging callback.
603		793
604	Example: a very simple logging callback, simply dump the message to STDOUT	794	Example: a very simple logging callback, simply dump the message to STDOUT
605	and do not consume it.	795	and do not consume it.
606		796
607	$ctx->log_cb (sub { print STDERR shift; 0 });	797	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
615	your program.	805	your program.
616		806
617	$ctx->levels ("debug", "trace");	807	$ctx->levels ("debug", "trace");
618	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	808	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
619		809
620	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	810	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
621		811
622	Replaces the formatting callback on the context (C<undef> restores the	812	Replaces the formatting callback on the context (C<undef> restores the
623	default formatter).	813	default formatter).
624		814
625	The callback is passed the (possibly fractional) timestamp, the original	815	The callback is passed the (possibly fractional) timestamp, the original
626	logging context, the (numeric) logging level and the raw message string and needs to	816	logging context, the (numeric) logging level and the raw message string
627	return a formatted log message. In most cases this will be a string, but	817	and needs to return a formatted log message. In most cases this will be a
628	it could just as well be an array reference that just stores the values.	818	string, but it could just as well be an array reference that just stores
		819	the values.
		820
		821	If, for some reason, you want to use C<caller> to find out more baout the
		822	logger then you should walk up the call stack until you are no longer
		823	inside the C<AnyEvent::Log> package.
629		824
630	Example: format just the raw message, with numeric log level in angle	825	Example: format just the raw message, with numeric log level in angle
631	brackets.	826	brackets.
632		827
633	$ctx->fmt_cb (sub {	828	$ctx->fmt_cb (sub {
…		…
650	"$msg->[3]";	845	"$msg->[3]";
651		846
652	0	847	0
653	});	848	});
654		849
		850	=item $ctx->log_to_warn
		851
		852	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		853	(usually this logs to STDERR).
		854
		855	=item $ctx->log_to_file ($path)
		856
		857	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		858
		859	=item $ctx->log_to_path ($path)
		860
		861	Same as C<< ->log_to_file >>, but opens the file for each message. This
		862	is much slower, but allows you to change/move/rename/delete the file at
		863	basically any time.
		864
		865	Needless(?) to say, if you do not want to be bitten by some evil person
		866	calling C<chdir>, the path should be absolute. Doesn't help with
		867	C<chroot>, but hey...
		868
		869	=item $ctx->log_to_syslog ([$facility])
		870
		871	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
		872	all the others in the obvious way. If specified, then the C<$facility> is
		873	used as the facility (C<user>, C<auth>, C<local0> and so on). The default
		874	facility is C<user>.
		875
		876	Note that this function also sets a C<fmt_cb> - the logging part requires
		877	an array reference with [$level, $str] as input.
		878
655	=cut	879	=cut
656		880
657	sub log_cb {	881	sub log_cb {
658	my ($ctx, $cb) = @_;	882	my ($ctx, $cb) = @_;
659		883
…		…
664	my ($ctx, $cb) = @_;	888	my ($ctx, $cb) = @_;
665		889
666	$ctx->[4] = $cb;	890	$ctx->[4] = $cb;
667	}	891	}
668		892
		893	sub log_to_warn {
		894	my ($ctx, $path) = @_;
		895
		896	$ctx->log_cb (sub {
		897	warn shift;
		898	0
		899	});
		900	}
		901
		902	sub log_to_file {
		903	my ($ctx, $path) = @_;
		904
		905	open my $fh, ">>", $path
		906	or die "$path: $!";
		907
		908	$ctx->log_cb (sub {
		909	syswrite $fh, shift;
		910	0
		911	});
		912	}
		913
		914	sub log_to_path {
		915	my ($ctx, $path) = @_;
		916
		917	$ctx->log_cb (sub {
		918	open my $fh, ">>", $path
		919	or die "$path: $!";
		920
		921	syswrite $fh, shift;
		922	0
		923	});
		924	}
		925
		926	sub log_to_syslog {
		927	my ($ctx, $facility) = @_;
		928
		929	require Sys::Syslog;
		930
		931	$ctx->fmt_cb (sub {
		932	my $str = $_[3];
		933	$str =~ s/\n(?=.)/\n+ /g;
		934
		935	[$_[2], "($_[1][0]) $str"]
		936	});
		937
		938	$facility \|\|= "user";
		939
		940	$ctx->log_cb (sub {
		941	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		942
		943	Sys::Syslog::syslog ("$facility\|" . ($lvl - 1), $_)
		944	for split /\n/, $_[0][1];
		945
		946	0
		947	});
		948	}
		949
		950	=back
		951
		952	=head3 MESSAGE LOGGING
		953
		954	These methods allow you to log messages directly to a context, without
		955	going via your package context.
		956
		957	=over 4
		958
669	=item $ctx->log ($level, $msg[, @params])	959	=item $ctx->log ($level, $msg[, @params])
670		960
671	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	961	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
672		962
673	=item $logger = $ctx->logger ($level[, \$enabled])	963	=item $logger = $ctx->logger ($level[, \$enabled])
…		…
678	=cut	968	=cut
679		969
680	*log = \&AnyEvent::Log::_log;	970	*log = \&AnyEvent::Log::_log;
681	*logger = \&AnyEvent::Log::_logger;	971	*logger = \&AnyEvent::Log::_logger;
682		972
		973	=back
		974
		975	=cut
		976
		977	package AnyEvent::Log;
		978
		979	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		980
		981	Logging can also be configured by setting the environment variable
		982	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		983
		984	The value consists of one or more logging context specifications separated
		985	by C<:> or whitespace. Each logging specification in turn starts with a
		986	context name, followed by C<=>, followed by zero or more comma-separated
		987	configuration directives, here are some examples:
		988
		989	# set default logging level
		990	filter=warn
		991
		992	# log to file instead of to stderr
		993	log=file=/tmp/mylog
		994
		995	# log to file in addition to stderr
		996	log=+%file:%file=file=/tmp/mylog
		997
		998	# enable debug log messages, log warnings and above to syslog
		999	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		1000
		1001	# log trace messages (only) from AnyEvent::Debug to file
		1002	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		1003
		1004	A context name in the log specification can be any of the following:
		1005
		1006	=over 4
		1007
		1008	=item C<collect>, C<filter>, C<log>
		1009
		1010	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		1011	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		1012
		1013	=item C<%name>
		1014
		1015	Context names starting with a C<%> are anonymous contexts created when the
		1016	name is first mentioned. The difference to package contexts is that by
		1017	default they have no attached slaves.
		1018
		1019	=item a perl package name
		1020
		1021	Any other string references the logging context associated with the given
		1022	Perl C<package>. In the unlikely case where you want to specify a package
		1023	context that matches on of the other context name forms, you can add a
		1024	C<::> to the package name to force interpretation as a package.
		1025
		1026	=back
		1027
		1028	The configuration specifications can be any number of the following:
		1029
		1030	=over 4
		1031
		1032	=item C<stderr>
		1033
		1034	Configures the context to use Perl's C<warn> function (which typically
		1035	logs to C<STDERR>). Works like C<log_to_warn>.
		1036
		1037	=item C<file=>I<path>
		1038
		1039	Configures the context to log to a file with the given path. Works like
		1040	C<log_to_file>.
		1041
		1042	=item C<path=>I<path>
		1043
		1044	Configures the context to log to a file with the given path. Works like
		1045	C<log_to_path>.
		1046
		1047	=item C<syslog> or C<syslog=>I<expr>
		1048
		1049	Configures the context to log to syslog. If I<expr> is given, then it is
		1050	evaluated in the L<Sys::Syslog> package, so you could use:
		1051
		1052	log=syslog=LOG_LOCAL0
		1053
		1054	=item C<nolog>
		1055
		1056	Configures the context to not log anything by itself, which is the
		1057	default. Same as C<< $ctx->log_cb (undef) >>.
		1058
		1059	=item C<0> or C<off>
		1060
		1061	Sets the logging level of the context ot C<0>, i.e. all messages will be
		1062	filtered out.
		1063
		1064	=item C<all>
		1065
		1066	Enables all logging levels, i.e. filtering will effectively be switched
		1067	off (the default).
		1068
		1069	=item C<only>
		1070
		1071	Disables all logging levels, and changes the interpretation of following
		1072	level specifications to enable the specified level only.
		1073
		1074	Example: only enable debug messages for a context.
		1075
		1076	context=only,debug
		1077
		1078	=item C<except>
		1079
		1080	Enables all logging levels, and changes the interpretation of following
		1081	level specifications to disable that level. Rarely used.
		1082
		1083	Example: enable all logging levels except fatal and trace (this is rather
		1084	nonsensical).
		1085
		1086	filter=exept,fatal,trace
		1087
		1088	=item C<level>
		1089
		1090	Enables all logging levels, and changes the interpretation of following
		1091	level specifications to be "that level or any higher priority
		1092	message". This is the default.
		1093
		1094	Example: log anything at or above warn level.
		1095
		1096	filter=warn
		1097
		1098	# or, more verbose
		1099	filter=only,level,warn
		1100
		1101	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1102
		1103	A numeric loglevel or the name of a loglevel will be interpreted according
		1104	to the most recent C<only>, C<except> or C<level> directive. By default,
		1105	specifying a logging level enables that and any higher priority messages.
		1106
		1107	=item C<+>I<context>
		1108
		1109	Attaches the named context as slave to the context.
		1110
		1111	=item C<+>
		1112
		1113	A line C<+> detaches all contexts, i.e. clears the slave list from the
		1114	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1115	but package contexts have the parent context as slave by default.
		1116
		1117	Example: log messages from My::Module to a file, do not send them to the
		1118	default log collector.
		1119
		1120	My::Module=+,file=/tmp/mymodulelog
		1121
		1122	=back
		1123
		1124	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1125	usual, so to log to a file containing a comma, colon, backslash and some
		1126	spaces in the filename, you would do this:
		1127
		1128	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1129
		1130	Since whitespace (which includes newlines) is allowed, it is fine to
		1131	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1132
		1133	PERL_ANYEVENT_LOG="
		1134	filter=warn
		1135	AnyEvent::Debug=+%trace
		1136	%trace=only,trace,+log
		1137	" myprog
		1138
		1139	Also, in the unlikely case when you want to concatenate specifications,
		1140	use whitespace as separator, as C<::> will be interpreted as part of a
		1141	module name, an empty spec with two separators:
		1142
		1143	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1144
		1145	=cut
		1146
		1147	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1148	my %anon;
		1149
		1150	my $pkg = sub {
		1151	$_[0] eq "log" ? $LOG
		1152	: $_[0] eq "filter" ? $FILTER
		1153	: $_[0] eq "collect" ? $COLLECT
		1154	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= ctx undef)
		1155	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1156	: die # never reached?
		1157	};
		1158
		1159	/\G[[:space:]]+/gc; # skip initial whitespace
		1160
		1161	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1162	my $ctx = $pkg->($1);
		1163	my $level = "level";
		1164
		1165	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1166	for ("$1") {
		1167	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1168	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1169	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1170	} elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ($1);
		1171	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1172	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1173	} elsif ($_ eq "+" ) { $ctx->slaves;
		1174	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1175	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1176	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1177	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1178	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1179	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1180	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1181	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1182	}
		1183	}
		1184
		1185	/\G,/gc or last;
		1186	}
		1187
		1188	/\G[:[:space:]]+/gc or last;
		1189	}
		1190
		1191	/\G[[:space:]]+/gc; # skip trailing whitespace
		1192
		1193	if (/\G(.+)/g) {
		1194	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1195	}
		1196	}
		1197
683	1;	1198	1;
		1199
		1200	=head1 EXAMPLES
		1201
		1202	This section shows some common configurations, both as code, and as
		1203	C<PERL_ANYEVENT_LOG> string.
		1204
		1205	=over 4
		1206
		1207	=item Setting the global logging level.
		1208
		1209	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1210	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1211	the root context at runtime:
		1212
		1213	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1214
		1215	PERL_ANYEVENT_LOG=log=warn
		1216
		1217	$AnyEvent::Log::FILTER->level ("warn");
		1218
		1219	=item Append all messages to a file instead of sending them to STDERR.
		1220
		1221	This is affected by the global logging level.
		1222
		1223	$AnyEvent::Log::LOG->log_to_file ($path);
		1224
		1225	PERL_ANYEVENT_LOG=log=file=/some/path
		1226
		1227	=item Write all messages with priority C<error> and higher to a file.
		1228
		1229	This writes them only when the global logging level allows it, because
		1230	it is attached to the default context which is invoked I<after> global
		1231	filtering.
		1232
		1233	$AnyEvent::Log::FILTER->attach
		1234	new AnyEvent::Log::Ctx log_to_file => $path);
		1235
		1236	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1237
		1238	This writes them regardless of the global logging level, because it is
		1239	attached to the toplevel context, which receives all messages I<before>
		1240	the global filtering.
		1241
		1242	$AnyEvent::Log::COLLECT->attach (
		1243	new AnyEvent::Log::Ctx log_to_file => $path);
		1244
		1245	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1246
		1247	In both cases, messages are still written to STDERR.
		1248
		1249	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1250
		1251	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1252	context - this simply circumvents the global filtering for trace messages.
		1253
		1254	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1255	$debug->attach ($AnyEvent::Log::LOG);
		1256
		1257	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1258
		1259	This of course works for any package, not just L<AnyEvent::Debug>, but
		1260	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1261	default.
684		1262
685	=back	1263	=back
686		1264
687	=head1 AUTHOR	1265	=head1 AUTHOR
688		1266
689	Marc Lehmann <schmorp@schmorp.de>	1267	Marc Lehmann <schmorp@schmorp.de>
690	http://home.schmorp.de/	1268	http://home.schmorp.de/
691		1269
692	=cut	1270	=cut
		1271

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs. Revision 1.40 by root, Fri Aug 26 16:18:01 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs.
Revision 1.40 by root, Fri Aug 26 16:18:01 2011 UTC