[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 1.55 by root, Fri Mar 30 21:31:52 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
…		…
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. The
		946	function might return before the log file has been opened or created.
		947
		948	=item $ctx->log_to_path ($path)
		949
		950	Same as C<< ->log_to_file >>, but opens the file for each message. This
		951	is much slower, but allows you to change/move/rename/delete the file at
		952	basically any time.
		953
		954	Needless(?) to say, if you do not want to be bitten by some evil person
		955	calling C<chdir>, the path should be absolute. Doesn't help with
		956	C<chroot>, but hey...
		957
		958	=item $ctx->log_to_syslog ([$facility])
		959
		960	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
		961	all the others in the obvious way. If specified, then the C<$facility> is
		962	used as the facility (C<user>, C<auth>, C<local0> and so on). The default
		963	facility is C<user>.
		964
		965	Note that this function also sets a C<fmt_cb> - the logging part requires
		966	an array reference with [$level, $str] as input.
		967
655	=cut	968	=cut
656		969
657	sub log_cb {	970	sub log_cb {
658	my ($ctx, $cb) = @_;	971	my ($ctx, $cb) = @_;
659		972
…		…
664	my ($ctx, $cb) = @_;	977	my ($ctx, $cb) = @_;
665		978
666	$ctx->[4] = $cb;	979	$ctx->[4] = $cb;
667	}	980	}
668		981
		982	sub log_to_warn {
		983	my ($ctx, $path) = @_;
		984
		985	$ctx->log_cb (sub {
		986	warn shift;
		987	0
		988	});
		989	}
		990
		991	# this function is a good example of why threads are a must,
		992	# simply for priority inversion.
		993	sub _log_to_disk {
		994	# eval'uating this at runtime saves 220kb rss - perl has become
		995	# an insane memory waster.
		996	eval q{ # poor man's autoloading {}
		997	sub _log_to_disk {
		998	my ($ctx, $path, $keepopen) = @_;
		999
		1000	my $fh;
		1001	my @queue;
		1002	my $delay;
		1003	my $disable;
		1004
		1005	use AnyEvent::IO ();
		1006
		1007	my $kick = sub {
		1008	undef $delay;
		1009	return unless @queue;
		1010	$delay = 1;
		1011
		1012	# we pass $kick to $kick, so $kick itself doesn't keep a reference to $kick.
		1013	my $kick = shift;
		1014
		1015	# write one or more messages
		1016	my $write = sub {
		1017	# we write as many messages as have been queued
		1018	my $data = join "", @queue;
		1019	@queue = ();
		1020
		1021	AnyEvent::IO::ae_write $fh, $data, sub {
		1022	$disable = 1;
		1023	@_
		1024	? ($_[0] == length $data or AE::log 4 => "unable to write to logfile '$path': short write")
		1025	: AE::log 4 => "unable to write to logfile '$path': $!";
		1026	undef $disable;
		1027
		1028	if ($keepopen) {
		1029	$kick->($kick);
		1030	} else {
		1031	AnyEvent::IO::ae_close ($fh, sub {
		1032	undef $fh;
		1033	$kick->($kick);
		1034	});
		1035	}
		1036	};
		1037	};
		1038
		1039	if ($fh) {
		1040	$write->();
		1041	} else {
		1042	AnyEvent::IO::ae_open
		1043	$path,
		1044	AnyEvent::IO::O_CREAT \| AnyEvent::IO::O_WRONLY \| AnyEvent::IO::O_APPEND,
		1045	0666,
		1046	sub {
		1047	$fh = shift
		1048	or do {
		1049	$disable = 1;
		1050	AE::log 4 => "unable to open logfile '$path': $!";
		1051	undef $disable;
		1052	return;
		1053	};
		1054
		1055	$write->();
		1056	}
		1057	;
		1058	}
		1059	};
		1060
		1061	$ctx->log_cb (sub {
		1062	return if $disable;
		1063	push @queue, shift;
		1064	$kick->($kick) unless $delay;
		1065	0
		1066	});
		1067
		1068	$kick->($kick) if $keepopen; # initial open
		1069	};
		1070	};
		1071	die if $@;
		1072	&_log_to_disk
		1073	}
		1074
		1075	sub log_to_file {
		1076	my ($ctx, $path) = @_;
		1077
		1078	_log_to_disk $ctx, $path, 1;
		1079	}
		1080
		1081	sub log_to_path {
		1082	my ($ctx, $path) = @_;
		1083
		1084	_log_to_disk $ctx, $path, 0;
		1085	}
		1086
		1087	sub log_to_syslog {
		1088	my ($ctx, $facility) = @_;
		1089
		1090	require Sys::Syslog;
		1091
		1092	$ctx->fmt_cb (sub {
		1093	my $str = $_[3];
		1094	$str =~ s/\n(?=.)/\n+ /g;
		1095
		1096	[$_[2], "($_[1][0]) $str"]
		1097	});
		1098
		1099	$facility \|\|= "user";
		1100
		1101	$ctx->log_cb (sub {
		1102	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		1103
		1104	Sys::Syslog::syslog ("$facility\|" . ($lvl - 1), $_)
		1105	for split /\n/, $_[0][1];
		1106
		1107	0
		1108	});
		1109	}
		1110
		1111	=back
		1112
		1113	=head3 MESSAGE LOGGING
		1114
		1115	These methods allow you to log messages directly to a context, without
		1116	going via your package context.
		1117
		1118	=over 4
		1119
669	=item $ctx->log ($level, $msg[, @params])	1120	=item $ctx->log ($level, $msg[, @params])
670		1121
671	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	1122	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		1123
		1124	Example: log a message in the context of another package.
		1125
		1126	(AnyEvent::Log::ctx "Other::Package")->log (warn => "heely bo");
672		1127
673	=item $logger = $ctx->logger ($level[, \$enabled])	1128	=item $logger = $ctx->logger ($level[, \$enabled])
674		1129
675	Same as C<AnyEvent::Log::logger>, but uses the given context as log	1130	Same as C<AnyEvent::Log::logger>, but uses the given context as log
676	context.	1131	context.
…		…
678	=cut	1133	=cut
679		1134
680	*log = \&AnyEvent::Log::_log;	1135	*log = \&AnyEvent::Log::_log;
681	*logger = \&AnyEvent::Log::_logger;	1136	*logger = \&AnyEvent::Log::_logger;
682		1137
683	1;	1138	=back
		1139
		1140	=cut
		1141
		1142	package AnyEvent::Log;
		1143
		1144	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		1145
		1146	Logging can also be configured by setting the environment variable
		1147	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		1148
		1149	The value consists of one or more logging context specifications separated
		1150	by C<:> or whitespace. Each logging specification in turn starts with a
		1151	context name, followed by C<=>, followed by zero or more comma-separated
		1152	configuration directives, here are some examples:
		1153
		1154	# set default logging level
		1155	filter=warn
		1156
		1157	# log to file instead of to stderr
		1158	log=file=/tmp/mylog
		1159
		1160	# log to file in addition to stderr
		1161	log=+%file:%file=file=/tmp/mylog
		1162
		1163	# enable debug log messages, log warnings and above to syslog
		1164	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		1165
		1166	# log trace messages (only) from AnyEvent::Debug to file
		1167	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		1168
		1169	A context name in the log specification can be any of the following:
		1170
		1171	=over 4
		1172
		1173	=item C<collect>, C<filter>, C<log>
		1174
		1175	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		1176	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		1177
		1178	=item C<%name>
		1179
		1180	Context names starting with a C<%> are anonymous contexts created when the
		1181	name is first mentioned. The difference to package contexts is that by
		1182	default they have no attached slaves.
		1183
		1184	=item a perl package name
		1185
		1186	Any other string references the logging context associated with the given
		1187	Perl C<package>. In the unlikely case where you want to specify a package
		1188	context that matches on of the other context name forms, you can add a
		1189	C<::> to the package name to force interpretation as a package.
		1190
		1191	=back
		1192
		1193	The configuration specifications can be any number of the following:
		1194
		1195	=over 4
		1196
		1197	=item C<stderr>
		1198
		1199	Configures the context to use Perl's C<warn> function (which typically
		1200	logs to C<STDERR>). Works like C<log_to_warn>.
		1201
		1202	=item C<file=>I<path>
		1203
		1204	Configures the context to log to a file with the given path. Works like
		1205	C<log_to_file>.
		1206
		1207	=item C<path=>I<path>
		1208
		1209	Configures the context to log to a file with the given path. Works like
		1210	C<log_to_path>.
		1211
		1212	=item C<syslog> or C<syslog=>I<expr>
		1213
		1214	Configures the context to log to syslog. If I<expr> is given, then it is
		1215	evaluated in the L<Sys::Syslog> package, so you could use:
		1216
		1217	log=syslog=LOG_LOCAL0
		1218
		1219	=item C<nolog>
		1220
		1221	Configures the context to not log anything by itself, which is the
		1222	default. Same as C<< $ctx->log_cb (undef) >>.
		1223
		1224	=item C<cap=>I<level>
		1225
		1226	Caps logging messages entering this context at the given level, i.e.
		1227	reduces the priority of messages with higher priority than this level. The
		1228	default is C<0> (or C<off>), meaning the priority will not be touched.
		1229
		1230	=item C<0> or C<off>
		1231
		1232	Sets the logging level of the context to C<0>, i.e. all messages will be
		1233	filtered out.
		1234
		1235	=item C<all>
		1236
		1237	Enables all logging levels, i.e. filtering will effectively be switched
		1238	off (the default).
		1239
		1240	=item C<only>
		1241
		1242	Disables all logging levels, and changes the interpretation of following
		1243	level specifications to enable the specified level only.
		1244
		1245	Example: only enable debug messages for a context.
		1246
		1247	context=only,debug
		1248
		1249	=item C<except>
		1250
		1251	Enables all logging levels, and changes the interpretation of following
		1252	level specifications to disable that level. Rarely used.
		1253
		1254	Example: enable all logging levels except fatal and trace (this is rather
		1255	nonsensical).
		1256
		1257	filter=exept,fatal,trace
		1258
		1259	=item C<level>
		1260
		1261	Enables all logging levels, and changes the interpretation of following
		1262	level specifications to be "that level or any higher priority
		1263	message". This is the default.
		1264
		1265	Example: log anything at or above warn level.
		1266
		1267	filter=warn
		1268
		1269	# or, more verbose
		1270	filter=only,level,warn
		1271
		1272	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1273
		1274	A numeric loglevel or the name of a loglevel will be interpreted according
		1275	to the most recent C<only>, C<except> or C<level> directive. By default,
		1276	specifying a logging level enables that and any higher priority messages.
		1277
		1278	=item C<+>I<context>
		1279
		1280	Attaches the named context as slave to the context.
		1281
		1282	=item C<+>
		1283
		1284	A lone C<+> detaches all contexts, i.e. clears the slave list from the
		1285	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1286	but package contexts have the parent context as slave by default.
		1287
		1288	Example: log messages from My::Module to a file, do not send them to the
		1289	default log collector.
		1290
		1291	My::Module=+,file=/tmp/mymodulelog
		1292
		1293	=back
		1294
		1295	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1296	usual, so to log to a file containing a comma, colon, backslash and some
		1297	spaces in the filename, you would do this:
		1298
		1299	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1300
		1301	Since whitespace (which includes newlines) is allowed, it is fine to
		1302	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1303
		1304	PERL_ANYEVENT_LOG="
		1305	filter=warn
		1306	AnyEvent::Debug=+%trace
		1307	%trace=only,trace,+log
		1308	" myprog
		1309
		1310	Also, in the unlikely case when you want to concatenate specifications,
		1311	use whitespace as separator, as C<::> will be interpreted as part of a
		1312	module name, an empty spec with two separators:
		1313
		1314	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1315
		1316	=cut
		1317
		1318	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1319	my %anon;
		1320
		1321	my $pkg = sub {
		1322	$_[0] eq "log" ? $LOG
		1323	: $_[0] eq "filter" ? $FILTER
		1324	: $_[0] eq "collect" ? $COLLECT
		1325	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= do { my $ctx = ctx undef; $ctx->[0] = $_[0]; $ctx })
		1326	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1327	: die # never reached?
		1328	};
		1329
		1330	/\G[[:space:]]+/gc; # skip initial whitespace
		1331
		1332	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1333	my $ctx = $pkg->($1);
		1334	my $level = "level";
		1335
		1336	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1337	for ("$1") {
		1338	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1339	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1340	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1341	} elsif (/^syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ("$1");
		1342	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1343	} elsif (/^cap=(.+)/ ) { $ctx->cap ("$1");
		1344	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1345	} elsif ($_ eq "+" ) { $ctx->slaves;
		1346	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1347	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1348	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1349	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1350	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1351	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1352	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1353	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1354	}
		1355	}
		1356
		1357	/\G,/gc or last;
		1358	}
		1359
		1360	/\G[:[:space:]]+/gc or last;
		1361	}
		1362
		1363	/\G[[:space:]]+/gc; # skip trailing whitespace
		1364
		1365	if (/\G(.+)/g) {
		1366	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1367	}
		1368	}
		1369
		1370	=head1 EXAMPLES
		1371
		1372	This section shows some common configurations, both as code, and as
		1373	C<PERL_ANYEVENT_LOG> string.
		1374
		1375	=over 4
		1376
		1377	=item Setting the global logging level.
		1378
		1379	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1380	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1381	the root context at runtime:
		1382
		1383	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1384
		1385	PERL_ANYEVENT_LOG=log=warn
		1386
		1387	$AnyEvent::Log::FILTER->level ("warn");
		1388
		1389	=item Append all messages to a file instead of sending them to STDERR.
		1390
		1391	This is affected by the global logging level.
		1392
		1393	$AnyEvent::Log::LOG->log_to_file ($path);
		1394
		1395	PERL_ANYEVENT_LOG=log=file=/some/path
		1396
		1397	=item Write all messages with priority C<error> and higher to a file.
		1398
		1399	This writes them only when the global logging level allows it, because
		1400	it is attached to the default context which is invoked I<after> global
		1401	filtering.
		1402
		1403	$AnyEvent::Log::FILTER->attach (
		1404	new AnyEvent::Log::Ctx log_to_file => $path);
		1405
		1406	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1407
		1408	This writes them regardless of the global logging level, because it is
		1409	attached to the toplevel context, which receives all messages I<before>
		1410	the global filtering.
		1411
		1412	$AnyEvent::Log::COLLECT->attach (
		1413	new AnyEvent::Log::Ctx log_to_file => $path);
		1414
		1415	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1416
		1417	In both cases, messages are still written to STDERR.
		1418
		1419	=item Additionally log all messages with C<warn> and higher priority to
		1420	C<syslog>, but cap at C<error>.
		1421
		1422	This logs all messages to the default log target, but also logs messages
		1423	with priority C<warn> or higher (and not filtered otherwise) to syslog
		1424	facility C<user>. Messages with priority higher than C<error> will be
		1425	logged with level C<error>.
		1426
		1427	$AnyEvent::Log::LOG->attach (
		1428	new AnyEvent::Log::Ctx
		1429	level => "warn",
		1430	cap => "error",
		1431	syslog => "user",
		1432	);
		1433
		1434	PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
		1435
		1436	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1437
		1438	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1439	context - this simply circumvents the global filtering for trace messages.
		1440
		1441	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1442	$debug->attach ($AnyEvent::Log::LOG);
		1443
		1444	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1445
		1446	This of course works for any package, not just L<AnyEvent::Debug>, but
		1447	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1448	default.
684		1449
685	=back	1450	=back
686		1451
687	=head1 AUTHOR	1452	=head1 AUTHOR
688		1453
689	Marc Lehmann <schmorp@schmorp.de>	1454	Marc Lehmann <schmorp@schmorp.de>
690	http://home.schmorp.de/	1455	http://home.schmorp.de/
691		1456
692	=cut	1457	=cut
		1458
		1459	1
		1460

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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 1.55 by root, Fri Mar 30 21:31:52 2012 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 1.55 by root, Fri Mar 30 21:31:52 2012 UTC