[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 1.52 by root, Thu Mar 22 19:27:30 2012 UTC

…		…
2		2
3	AnyEvent::Log - simple logging "framework"	3	AnyEvent::Log - simple logging "framework"
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	# simple use	7	Simple uses:
		8
8	use AnyEvent;	9	use AnyEvent;
9		10
10	AE::log debug => "hit my knee";	11	AE::log fatal => "no config found, cannot continue"; # never returns
11	AE::log warn => "it's a bit too hot";	12	AE::log alert => "the battery died";
12	AE::log error => "the flag was false!";	13	AE::log crit => "the battery temperature is too hot";
13	AE::log fatal => "the bit toggled! run!";	14	AE::log error => "division by zero attempted";
		15	AE::log warn => "couldn't delete the file";
		16	AE::log note => "wanted to create config, but config already exists";
		17	AE::log info => "file soandso successfully deleted";
		18	AE::log debug => "the function returned 3";
		19	AE::log trace => "going to call function abc";
14		20
15	# "complex" use	21	Log level overview:
		22
		23	LVL NAME SYSLOG PERL NOTE
		24	1 fatal emerg exit system unusable, aborts program!
		25	2 alert failure in primary system
		26	3 critical crit failure in backup system
		27	4 error err die non-urgent program errors, a bug
		28	5 warn warning possible problem, not necessarily error
		29	6 note notice unusual conditions
		30	7 info normal messages, no action required
		31	8 debug debugging messages for development
		32	9 trace copious tracing output
		33
		34	"Complex" uses (for speed sensitive code, e.g. trace/debug messages):
		35
16	use AnyEvent::Log;	36	use AnyEvent::Log;
17		37
18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;	38	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19		39
20	$tracer->("i am here") if $trace;	40	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	41	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		42
23	# configuration	43	Configuration (also look at the EXAMPLES section):
24		44
25	# set logging for this package to 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, ever, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number	67	errors and more important messages will be logged, unless you set
51	before starting your program, or change the logging level at runtime wiht	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
		83	The amount of documentation might indicate otherwise, but the runtime part
		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.
		127
62	=head1 LOGGING FUNCTIONS	128	=head1 LOGGING FUNCTIONS
63		129
64	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
65	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,
66	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>
67	loaded.	133	module is loaded.
68		134
69	=over 4	135	=over 4
70		136
71	=cut	137	=cut
72		138
73	package AnyEvent::Log;	139	package AnyEvent::Log;
74		140
75	use Carp ();	141	use Carp ();
76	use POSIX ();	142	use POSIX ();
77		143
		144	# layout of a context
		145	# 0 1 2 3 4, 5
		146	# [$title, $level, %$slaves, &$logcb, &$fmtcb, $cap]
		147
78	use AnyEvent (); BEGIN { AnyEvent::common_sense }	148	use AnyEvent (); BEGIN { AnyEvent::common_sense }
79	use AnyEvent::Util ();	149	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
		150
		151	our $VERSION = $AnyEvent::VERSION;
		152
		153	our ($COLLECT, $FILTER, $LOG);
80		154
81	our ($now_int, $now_str1, $now_str2);	155	our ($now_int, $now_str1, $now_str2);
82		156
83	# Format Time, not public - yet?	157	# Format Time, not public - yet?
84	sub ft($) {	158	sub ft($) {
…		…
89	if $now_int != $i;	163	if $now_int != $i;
90		164
91	"$now_str1$f$now_str2"	165	"$now_str1$f$now_str2"
92	}	166	}
93		167
94	our %CTX; # all logging contexts	168	our %CTX; # all package contexts
95		169
96	# creates a default package context object for the given package	170	# creates a default package context object for the given package
97	sub _pkg_ctx($) {	171	sub _pkg_ctx($) {
98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	172	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
99		173
100	# link "parent" package	174	# link "parent" package
101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "";	175	my $parent = $_[0] =~ /^(.+)::/
		176	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		177	: $COLLECT;
102		178
103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
104	$ctx->[2]{$pkg+0} = $pkg;	179	$ctx->[2]{$parent+0} = $parent;
105		180
106	$ctx	181	$ctx
107	}	182	}
108		183
109	=item AnyEvent::Log::log $level, $msg[, @args]	184	=item AnyEvent::Log::log $level, $msg[, @args]
110		185
111	Requests logging of the given C<$msg> with the given log level (1..9).	186	Requests logging of the given C<$msg> with the given log level, and
112	You can also use the following strings as log level: C<fatal> (1),	187	returns true if the message was logged I<somewhere>.
113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114	C<info> (7), C<debug> (8), C<trace> (9).
115		188
116	For C<fatal> log levels, the program will abort.	189	For loglevel C<fatal>, the program will abort.
117		190
118	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	191	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
119	C<$msg> is interpreted as an sprintf format string.	192	C<$msg> is interpreted as an sprintf format string.
120		193
121	The C<$msg> should not end with C<\n>, but may if that is convenient for	194	The C<$msg> should not end with C<\n>, but may if that is convenient for
…		…
124	Last not least, C<$msg> might be a code reference, in which case it is	197	Last not least, C<$msg> might be a code reference, in which case it is
125	supposed to return the message. It will be called only then the message	198	supposed to return the message. It will be called only then the message
126	actually gets logged, which is useful if it is costly to create the	199	actually gets logged, which is useful if it is costly to create the
127	message in the first place.	200	message in the first place.
128		201
		202	This function takes care of saving and restoring C<$!> and C<$@>, so you
		203	don't have to.
		204
129	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
130	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.
131		210
132	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
133	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
134	need any additional functionality), as those functions will load the	213	need any additional functionality), as those functions will load the
135	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.
136		215
137	Also, if you otpionally generate a lot of debug messages (such as when	216	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	217	tracing some code), you should look into using a logger callback and a
139	boolean enabler (see C<logger>, below).	218	boolean enabler (see C<logger>, below).
140		219
141	Example: log something at error level.	220	Example: log something at error level.
142		221
…		…
152		231
153	=cut	232	=cut
154		233
155	# also allow syslog equivalent names	234	# also allow syslog equivalent names
156	our %STR2LEVEL = (	235	our %STR2LEVEL = (
157	fatal => 1, emerg => 1,	236	fatal => 1, emerg => 1, exit => 1,
158	alert => 2,	237	alert => 2,
159	critical => 3, crit => 3,	238	critical => 3, crit => 3,
160	error => 4, err => 4,	239	error => 4, err => 4, die => 4,
161	warn => 5, warning => 5,	240	warn => 5, warning => 5,
162	note => 6, notice => 6,	241	note => 6, notice => 6,
163	info => 7,	242	info => 7,
164	debug => 8,	243	debug => 8,
165	trace => 9,	244	trace => 9,
166	);	245	);
167		246
168	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	}
169		259
170	AnyEvent::post_detect {	260	AnyEvent::post_detect {
171	*now = \&AE::now;	261	exact_time $TIME_EXACT;
172	};	262	};
173		263
174	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);
175		265
176	# time, ctx, level, msg	266	# time, ctx, level, msg
177	sub _format($$$$) {	267	sub _format($$$$) {
178	my $pfx = ft $_[0];	268	my $ts = ft $_[0];
		269	my $ct = " ";
		270
179	my @res;	271	my @res;
180		272
181	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {	273	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
182	push @res, "$pfx $_\n";	274	push @res, "$ts$ct$_\n";
183	$pfx = "\t";	275	$ct = " + ";
184	}	276	}
185		277
186	join "", @res	278	join "", @res
		279	}
		280
		281	sub fatal_exit() {
		282	exit 1;
187	}	283	}
188		284
189	sub _log {	285	sub _log {
190	my ($ctx, $level, $format, @args) = @_;	286	my ($ctx, $level, $format, @args) = @_;
191		287
		288	$level = $level > 0 && $level <= 9
		289	? $level+0
192	$level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	290	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
193		291
194	my $mask = 1 << $level;	292	my $mask = 1 << $level;
195		293
196	my (@ctx, $now, $fmt);	294	my ($success, %seen, @ctx, $now, @fmt);
197		295
198	do {	296	do
199	# skip if masked	297	{
200	next unless $ctx->[1] & $mask;	298	# if !ref, then it's a level number
		299	if (!ref $ctx) {
		300	$level = $ctx;
		301	} elsif ($ctx->[1] & $mask and !$seen{$ctx+0}++) {
		302	# logging/recursing into this context
201		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
202	if ($ctx->[3]) {	311	if ($ctx->[3]) {
203	# logging target found	312	# logging target found
204		313
		314	local ($!, $@);
		315
205	# now get raw message, unless we have it already	316	# now get raw message, unless we have it already
206	unless ($now) {	317	unless ($now) {
207	$format = $format->() if ref $format;	318	$format = $format->() if ref $format;
208	$format = sprintf $format, @args if @args;	319	$format = sprintf $format, @args if @args;
209	$format =~ s/\n$//;	320	$format =~ s/\n$//;
210	$now = AE::now;	321	$now = _ts;
		322	};
		323
		324	# format msg
		325	my $str = $ctx->[4]
		326	? $ctx->[4]($now, $_[0], $level, $format)
		327	: ($fmt[$level] \|\|= _format $now, $_[0], $level, $format);
		328
		329	$success = 1;
		330
		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
		335	}
211	};	336	}
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	}	337	}
221
222	# not masked, not consume - propagate to parent contexts
223	push @ctx, values %{ $ctx->[2] };
224	} while $ctx = pop @ctx;	338	while $ctx = pop @ctx;
225		339
226	exit 1 if $level <= 1;	340	fatal_exit if $level <= 1;
		341
		342	$success
227	}	343	}
228		344
229	sub log($$;@) {	345	sub log($$;@) {
230	_log	346	_log
231	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	347	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
232	@_;	348	@_;
233	}	349	}
234		350
235	AnyEvent::log = AE::log = \&log;
236
237	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	351	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
238		352
239	Creates a code reference that, when called, acts as if the	353	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	354	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	355	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
242	the C<AnyEvent::Log::log> function:	356	the C<AnyEvent::Log::log> function:
243		357
244	my $debug_log = AnyEvent::Log::logger "debug";	358	my $debug_log = AnyEvent::Log::logger "debug";
245		359
…		…
270	# and later in your program	384	# and later in your program
271	$debug_log->("yo, stuff here") if $debug;	385	$debug_log->("yo, stuff here") if $debug;
272		386
273	$debug and $debug_log->("123");	387	$debug and $debug_log->("123");
274		388
275	Note: currently the enabled var is always true - that will be fixed in a
276	future version :)
277
278	=cut	389	=cut
279		390
280	our %LOGGER;	391	our %LOGGER;
281		392
282	# re-assess logging status for all loggers	393	# re-assess logging status for all loggers
283	sub _reassess {	394	sub _reassess {
		395	local $SIG{__DIE__};
		396	my $die = sub { die };
		397
284	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	398	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
285	my ($ctx, $level, $renabled) = @$_;	399	my ($ctx, $level, $renabled) = @$_;
286		400
287	# to detetc whether a message would be logged, we # actually	401	# 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	402	# try to log one and die. this isn't fast, but we can be
289	# sure that the logging decision is correct :)	403	# sure that the logging decision is correct :)
290		404
291	$$renabled = !eval {	405	$$renabled = !eval {
292	local $SIG{__DIE__};
293
294	_log $ctx, $level, sub { die };	406	_log $ctx, $level, $die;
295		407
296	1	408	1
297	};	409	};
298
299	$$renabled = 1; # TODO
300	}	410	}
301	}	411	}
302		412
303	sub _logger($;$) {	413	sub _logger {
304	my ($ctx, $level, $renabled) = @_;	414	my ($ctx, $level, $renabled) = @_;
305		415
306	$renabled \|\|= \my $enabled;
307
308	$$renabled = 1;	416	$$renabled = 1;
309		417
310	my $logger = [$ctx, $level, $renabled];	418	my $logger = [$ctx, $level, $renabled];
311		419
312	$LOGGER{$logger+0} = $logger;	420	$LOGGER{$logger+0} = $logger;
313		421
314	_reassess $logger+0;	422	_reassess $logger+0;
315		423
		424	require AnyEvent::Util unless $AnyEvent::Util::VERSION;
316	my $guard = AnyEvent::Util::guard {	425	my $guard = AnyEvent::Util::guard (sub {
317	# "clean up"	426	# "clean up"
318	delete $LOGGER{$logger+0};	427	delete $LOGGER{$logger+0};
319	};	428	});
320		429
321	sub {	430	sub {
322	$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
323		432
324	_log $ctx, $level, @_	433	_log $ctx, $level, @_
…		…
329	sub logger($;$) {	438	sub logger($;$) {
330	_logger	439	_logger
331	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	440	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
332	@_	441	@_
333	}	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.
334		458
335	=back	459	=back
336		460
337	=head1 LOGGING CONTEXTS	461	=head1 LOGGING CONTEXTS
338		462
…		…
351	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
352	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
353	actually logging the formatted message and telling C<AnyEvent::Log>	477	actually logging the formatted message and telling C<AnyEvent::Log>
354	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).
355		479
356	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
357	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
358	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
359	contexts.	483	contexts.
		484
		485	Each call to a logging function will log the message at most once per
		486	context, so it does not matter (much) if there are cycles or if the
		487	message can arrive at the same context via multiple paths.
360		488
361	=head2 DEFAULTS	489	=head2 DEFAULTS
362		490
363	By default, all logging contexts have an full set of log levels ("all"), a	491	By default, all logging contexts have an full set of log levels ("all"), a
364	disabled logging callback and the default formatting callback.	492	disabled logging callback and the default formatting callback.
365		493
366	Package contexts have the package name as logging title by default.	494	Package contexts have the package name as logging title by default.
367		495
368	They have exactly one parent - the context of the "parent" package. The	496	They have exactly one slave - the context of the "parent" package. The
369	parent package is simply defined to be the package name without the last	497	parent package is simply defined to be the package name without the last
370	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,	498	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371	and C<AnyEvent> becomes the empty string.	499	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		500	exception of the rule - just like the "parent" of any single-component
		501	package name in Perl is C<main>, the default slave of any top-level
		502	package context is C<$AnyEvent::Log::COLLECT>.
372		503
373	Since perl packages form only an approximate hierarchy, this parent	504	Since perl packages form only an approximate hierarchy, this slave
374	context can of course be removed.	505	context can of course be removed.
375		506
376	All other (anonymous) contexts have no parents and an empty title by	507	All other (anonymous) contexts have no slaves and an empty title by
377	default.	508	default.
378		509
379	When the module is first loaded, it configures the root context (the one	510	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
380	with the empty string) to simply dump all log messages to C<STDERR>,	511	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	512	anything anywhere by default. The purpose of this context is to provide
382	C<$ENV{PERL_ANYEVENT_VERBOSE}>.	513	a convenient place to override the global logging target or to attach
		514	additional log targets. It's not meant for filtering.
		515
		516	It then creates the C<$AnyEvent::Log::FILTER> context whose
		517	purpose is to suppress all messages with priority higher
		518	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		519	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		520	is to simply provide filtering according to some global log level.
		521
		522	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		523	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		524	leaves it at default config. Its purpose is simply to collect all log
		525	messages system-wide.
		526
		527	The hierarchy is then:
		528
		529	any package, eventually -> $COLLECT -> $FILTER -> $LOG
383		530
384	The effect of all this is that log messages, by default, wander up to the	531	The effect of all this is that log messages, by default, wander up to the
385	root context and will be logged to STDERR if their log level is less than	532	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
386	or equal to C<$ENV{PERL_ANYEVENT_VERBOSE}>.	533	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		534	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		535	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
387		536
		537	This makes it easy to set a global logging level (by modifying $FILTER),
		538	but still allow other contexts to send, for example, their debug and trace
		539	messages to the $LOG target despite the global logging level, or to attach
		540	additional log targets that log messages, regardless of the global logging
		541	level.
		542
		543	It also makes it easy to modify the default warn-logger ($LOG) to
		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.
		546
388	=head2 CREATING/FINDING A CONTEXT	547	=head2 CREATING/FINDING/DESTROYING CONTEXTS
389		548
390	=over 4	549	=over 4
391		550
392	=item $ctx = AnyEvent::Log::ctx [$pkg]	551	=item $ctx = AnyEvent::Log::ctx [$pkg]
393		552
…		…
411	: defined $pkg	570	: defined $pkg
412	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg	571	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
413	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	572	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
414	}	573	}
415		574
416	# create default root context	575	=item AnyEvent::Log::reset
417	{	576
418	my $root = ctx undef;	577	Resets all package contexts and recreates the default hierarchy if
419	$root->[0] = "";	578	necessary, i.e. resets the logging subsystem to defaults, as much as
420	$root->title ("default");	579	possible. This process keeps references to contexts held by other parts of
421	$root->level ($AnyEvent::VERBOSE); undef $AnyEvent::VERBOSE;	580	the program intact.
422	$root->log_cb (sub {	581
423	print STDERR shift;	582	This can be used to implement config-file (re-)loading: before loading a
424	0	583	configuration, reset all contexts.
		584
		585	=cut
		586
		587	our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
		588	$AnyEvent::VERBOSE = 9;
		589
		590	sub reset {
		591	# hard to kill complex data structures
		592	# we "recreate" all package loggers and reset the hierarchy
		593	while (my ($k, $v) = each %CTX) {
		594	@$v = ($k, (1 << 10) - 1 - 1, { });
		595
		596	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
425	});	597	}
426	$CTX{""} = $root;	598
		599	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		600	for $LOG, $FILTER, $COLLECT;
		601
		602	#$LOG->slaves;
		603	$LOG->title ('$AnyEvent::Log::LOG');
		604	$LOG->log_to_warn;
		605
		606	$FILTER->slaves ($LOG);
		607	$FILTER->title ('$AnyEvent::Log::FILTER');
		608	$FILTER->level ($ORIG_VERBOSE);
		609
		610	$COLLECT->slaves ($FILTER);
		611	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		612
		613	_reassess;
427	}	614	}
		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
		624	# create the default logger contexts
		625	$LOG = ctx undef;
		626	$FILTER = ctx undef;
		627	$COLLECT = ctx undef;
		628
		629	AnyEvent::Log::reset;
		630
		631	# hello, CPAN, please catch me
		632	package AnyEvent::Log::LOG;
		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;
		638
		639	package AnyEvent::Log::Ctx;
		640
		641	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		642
		643	This is a convenience constructor that makes it simpler to construct
		644	anonymous logging contexts.
		645
		646	Each key-value pair results in an invocation of the method of the same
		647	name as the key with the value as parameter, unless the value is an
		648	arrayref, in which case it calls the method with the contents of the
		649	array. The methods are called in the same order as specified.
		650
		651	Example: create a new logging context and set both the default logging
		652	level, some slave contexts and a logging callback.
		653
		654	$ctx = new AnyEvent::Log::Ctx
		655	title => "dubious messages",
		656	level => "error",
		657	log_cb => sub { print STDOUT shift; 0 },
		658	slaves => [$ctx1, $ctx, $ctx2],
		659	;
428		660
429	=back	661	=back
430		662
431	=cut	663	=cut
432		664
433	package AnyEvent::Log::Ctx;	665	sub new {
		666	my $class = shift;
434		667
435	# 0 1 2 3 4	668	my $ctx = AnyEvent::Log::ctx undef;
436	# [$title, $level, %$parents, &$logcb, &$fmtcb]	669
		670	while (@_) {
		671	my ($k, $v) = splice @_, 0, 2;
		672	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		673	}
		674
		675	bless $ctx, $class # do we really support subclassing, hmm?
		676	}
		677
437		678
438	=head2 CONFIGURING A LOG CONTEXT	679	=head2 CONFIGURING A LOG CONTEXT
439		680
440	The following methods can be used to configure the logging context.	681	The following methods can be used to configure the logging context.
441		682
…		…
490	Enables logging for the given levels, leaving all others unchanged.	731	Enables logging for the given levels, leaving all others unchanged.
491		732
492	=item $ctx->disable ($level[, $level...])	733	=item $ctx->disable ($level[, $level...])
493		734
494	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>.
495		758
496	=cut	759	=cut
497		760
498	sub _lvl_lst {	761	sub _lvl_lst {
499	map {	762	map {
…		…
501	: $_ eq "all" ? (1 .. 9)	764	: $_ eq "all" ? (1 .. 9)
502	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"	765	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
503	} @_	766	} @_
504	}	767	}
505		768
		769	sub _lvl {
		770	$_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1]
		771	}
		772
506	our $NOP_CB = sub { 0 };	773	our $NOP_CB = sub { 0 };
507		774
508	sub levels {	775	sub levels {
509	my $ctx = shift;	776	my $ctx = shift;
510	$ctx->[1] = 0;	777	$ctx->[1] = 0;
…		…
513	AnyEvent::Log::_reassess;	780	AnyEvent::Log::_reassess;
514	}	781	}
515		782
516	sub level {	783	sub level {
517	my $ctx = shift;	784	my $ctx = shift;
518	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
519
520	$ctx->[1] = ((1 << $lvl) - 1) << 1;	785	$ctx->[1] = ((1 << &_lvl) - 1) << 1;
521	AnyEvent::Log::_reassess;	786	AnyEvent::Log::_reassess;
522	}	787	}
523		788
524	sub enable {	789	sub enable {
525	my $ctx = shift;	790	my $ctx = shift;
…		…
533	$ctx->[1] &= ~(1 << $_)	798	$ctx->[1] &= ~(1 << $_)
534	for &_lvl_lst;	799	for &_lvl_lst;
535	AnyEvent::Log::_reassess;	800	AnyEvent::Log::_reassess;
536	}	801	}
537		802
		803	sub cap {
		804	my $ctx = shift;
		805	$ctx->[5] = &_lvl;
		806	}
		807
538	=back	808	=back
539		809
540	=head3 PARENT CONTEXTS	810	=head3 SLAVE CONTEXTS
541		811
542	The following methods attach and detach another logging context to a	812	The following methods attach and detach another logging context to a
543	logging context.	813	logging context.
544		814
545	Log messages are propagated to all parent contexts, unless the logging	815	Log messages are propagated to all slave contexts, unless the logging
546	callback consumes the message.	816	callback consumes the message.
547		817
548	=over 4	818	=over 4
549		819
550	=item $ctx->attach ($ctx2[, $ctx3...])	820	=item $ctx->attach ($ctx2[, $ctx3...])
551		821
552	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
553	to add a context twice (the second add will be ignored).	823	to add a context twice (the second add will be ignored).
554		824
555	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.
556		826
557	=item $ctx->detach ($ctx2[, $ctx3...])	827	=item $ctx->detach ($ctx2[, $ctx3...])
558		828
559	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
560	to remove a context that hasn't been added.	830	to remove a context that hasn't been added.
561		831
562	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.
		833
		834	=item $ctx->slaves ($ctx2[, $ctx3...])
		835
		836	Replaces all slaves attached to this context by the ones given.
563		837
564	=cut	838	=cut
565		839
566	sub attach {	840	sub attach {
567	my $ctx = shift;	841	my $ctx = shift;
…		…
575		849
576	delete $ctx->[2]{$_+0}	850	delete $ctx->[2]{$_+0}
577	for map { AnyEvent::Log::ctx $_ } @_;	851	for map { AnyEvent::Log::ctx $_ } @_;
578	}	852	}
579		853
		854	sub slaves {
		855	undef $_[0][2];
		856	&attach;
		857	}
		858
580	=back	859	=back
581		860
582	=head3 MESSAGE LOGGING	861	=head3 LOG TARGETS
583		862
584	The following methods configure how the logging context actually does	863	The following methods configure how the logging context actually does
585	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
586	whatever it wants to do with it) and also allows you to log messages	865	whatever it wants to do with it).
587	directly to a context, without going via your package context.
588		866
589	=over 4	867	=over 4
590		868
591	=item $ctx->log_cb ($cb->($str))	869	=item $ctx->log_cb ($cb->($str)
592		870
593	Replaces the logging callback on the context (C<undef> disables the	871	Replaces the logging callback on the context (C<undef> disables the
594	logging callback).	872	logging callback).
595		873
596	The logging callback is responsible for handling formatted log messages	874	The logging callback is responsible for handling formatted log messages
597	(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
598	newline (and are possibly multiline themselves).	876	newline (and are possibly multiline themselves).
599		877
600	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
601	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
602	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.
603		881
604	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
605	and do not consume it.	883	and do not consume it.
606		884
607	$ctx->log_cb (sub { print STDERR shift; 0 });	885	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
615	your program.	893	your program.
616		894
617	$ctx->levels ("debug", "trace");	895	$ctx->levels ("debug", "trace");
618	$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
619		897
620	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	898	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
621		899
622	Replaces the formatting callback on the context (C<undef> restores the	900	Replaces the formatting callback on the context (C<undef> restores the
623	default formatter).	901	default formatter).
624		902
625	The callback is passed the (possibly fractional) timestamp, the original	903	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	904	logging context (object, not title), the (numeric) logging level and
627	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
628	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.
629		912
630	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
631	brackets.	914	brackets.
632		915
633	$ctx->fmt_cb (sub {	916	$ctx->fmt_cb (sub {
…		…
635		918
636	"<$lvl>$msg\n"	919	"<$lvl>$msg\n"
637	});	920	});
638		921
639	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
640	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.
641		924
642	$ctx->fmt_cb (sub { \@_ });	925	$ctx->fmt_cb (sub { \@_ });
643	$ctx->log_cb (sub {	926	$ctx->log_cb (sub {
644	my ($msg) = @_;	927	my ($msg) = @_;
645		928
…		…
650	"$msg->[3]";	933	"$msg->[3]";
651		934
652	0	935	0
653	});	936	});
654		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, $str] as input.
		966
655	=cut	967	=cut
656		968
657	sub log_cb {	969	sub log_cb {
658	my ($ctx, $cb) = @_;	970	my ($ctx, $cb) = @_;
659		971
…		…
664	my ($ctx, $cb) = @_;	976	my ($ctx, $cb) = @_;
665		977
666	$ctx->[4] = $cb;	978	$ctx->[4] = $cb;
667	}	979	}
668		980
		981	sub log_to_warn {
		982	my ($ctx, $path) = @_;
		983
		984	$ctx->log_cb (sub {
		985	warn shift;
		986	0
		987	});
		988	}
		989
		990	sub log_to_file {
		991	my ($ctx, $path) = @_;
		992
		993	open my $fh, ">>", $path
		994	or die "$path: $!";
		995
		996	$ctx->log_cb (sub {
		997	syswrite $fh, shift;
		998	0
		999	});
		1000	}
		1001
		1002	sub log_to_path {
		1003	my ($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
669	=item $ctx->log ($level, $msg[, @params])	1047	=item $ctx->log ($level, $msg[, @params])
670		1048
671	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	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");
672		1054
673	=item $logger = $ctx->logger ($level[, \$enabled])	1055	=item $logger = $ctx->logger ($level[, \$enabled])
674		1056
675	Same as C<AnyEvent::Log::logger>, but uses the given context as log	1057	Same as C<AnyEvent::Log::logger>, but uses the given context as log
676	context.	1058	context.
…		…
678	=cut	1060	=cut
679		1061
680	*log = \&AnyEvent::Log::_log;	1062	*log = \&AnyEvent::Log::_log;
681	*logger = \&AnyEvent::Log::_logger;	1063	*logger = \&AnyEvent::Log::_logger;
682		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
683	1;	1297	1;
		1298
		1299	=head1 EXAMPLES
		1300
		1301	This section shows some common configurations, both as code, and as
		1302	C<PERL_ANYEVENT_LOG> string.
		1303
		1304	=over 4
		1305
		1306	=item Setting the global logging level.
		1307
		1308	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1309	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1310	the root context at runtime:
		1311
		1312	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1313
		1314	PERL_ANYEVENT_LOG=log=warn
		1315
		1316	$AnyEvent::Log::FILTER->level ("warn");
		1317
		1318	=item Append all messages to a file instead of sending them to STDERR.
		1319
		1320	This is affected by the global logging level.
		1321
		1322	$AnyEvent::Log::LOG->log_to_file ($path);
		1323
		1324	PERL_ANYEVENT_LOG=log=file=/some/path
		1325
		1326	=item Write all messages with priority C<error> and higher to a file.
		1327
		1328	This writes them only when the global logging level allows it, because
		1329	it is attached to the default context which is invoked I<after> global
		1330	filtering.
		1331
		1332	$AnyEvent::Log::FILTER->attach (
		1333	new AnyEvent::Log::Ctx log_to_file => $path);
		1334
		1335	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1336
		1337	This writes them regardless of the global logging level, because it is
		1338	attached to the toplevel context, which receives all messages I<before>
		1339	the global filtering.
		1340
		1341	$AnyEvent::Log::COLLECT->attach (
		1342	new AnyEvent::Log::Ctx log_to_file => $path);
		1343
		1344	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1345
		1346	In both cases, messages are still written to STDERR.
		1347
		1348	=item Additionally log all messages with C<warn> and higher priority to
		1349	C<syslog>, but cap at C<error>.
		1350
		1351	This logs all messages to the default log target, but also logs messages
		1352	with priority C<warn> or higher (and not filtered otherwise) to syslog
		1353	facility C<user>. Messages with priority higher than C<error> will be
		1354	logged with level C<error>.
		1355
		1356	$AnyEvent::Log::LOG->attach (
		1357	new AnyEvent::Log::Ctx
		1358	level => "warn",
		1359	cap => "error",
		1360	syslog => "user",
		1361	);
		1362
		1363	PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
		1364
		1365	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1366
		1367	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1368	context - this simply circumvents the global filtering for trace messages.
		1369
		1370	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1371	$debug->attach ($AnyEvent::Log::LOG);
		1372
		1373	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1374
		1375	This of course works for any package, not just L<AnyEvent::Debug>, but
		1376	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1377	default.
684		1378
685	=back	1379	=back
686		1380
687	=head1 AUTHOR	1381	=head1 AUTHOR
688		1382
689	Marc Lehmann <schmorp@schmorp.de>	1383	Marc Lehmann <schmorp@schmorp.de>
690	http://home.schmorp.de/	1384	http://home.schmorp.de/
691		1385
692	=cut	1386	=cut
		1387

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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 1.52 by root, Thu Mar 22 19:27:30 2012 UTC

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Revision 1.52 by root, Thu Mar 22 19:27:30 2012 UTC