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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.8 by root, Fri Aug 19 19:20:36 2011 UTC vs.
Revision 1.18 by root, Sat Aug 20 15:57:35 2011 UTC

…		…
10	AE::log debug => "hit my knee";	10	AE::log debug => "hit my knee";
11	AE::log warn => "it's a bit too hot";	11	AE::log warn => "it's a bit too hot";
12	AE::log error => "the flag was false!";	12	AE::log error => "the flag was false!";
13	AE::log fatal => "the bit toggled! run!";	13	AE::log fatal => "the bit toggled! run!";
14		14
15	# complex use	15	# "complex" use
16	use AnyEvent::Log;	16	use AnyEvent::Log;
17		17
18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;	18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19		19
20	$tracer->("i am here") if $trace;	20	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		22
23	#TODO: config	23	# configuration
24	#TODO: ctx () becomes caller[0]...	24
		25	# set logging for the current package to errors and higher only
		26	AnyEvent::Log::ctx->level ("error");
		27
		28	# set logging globally to anything below debug
		29	$AnyEvent::Log::FILTER->level ("notice");
		30
		31	# see also EXAMPLES, below
25		32
26	=head1 DESCRIPTION	33	=head1 DESCRIPTION
27		34
28	This module implements a relatively simple "logging framework". It doesn't	35	This module implements a relatively simple "logging framework". It doesn't
29	attempt to be "the" logging solution or even "a" logging solution for	36	attempt to be "the" logging solution or even "a" logging solution for
30	AnyEvent - AnyEvent simply creates logging messages internally, and this	37	AnyEvent - AnyEvent simply creates logging messages internally, and this
31	module more or less exposes the mechanism, with some extra spiff to allow	38	module more or less exposes the mechanism, with some extra spiff to allow
32	using it from other modules as well.	39	using it from other modules as well.
33		40
34	Remember that the default verbosity level is C<0>, so nothing will be	41	Remember that the default verbosity level is C<0>, so nothing will be
35	logged, ever, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number	42	logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before
36	before starting your program.#TODO	43	starting your program, or change the logging level at runtime with
		44	something like:
37		45
38	Possible future extensions are to allow custom log targets (where the	46	use AnyEvent::Log;
39	level is an object), log filtering based on package, formatting, aliasing	47	AnyEvent::Log::FILTER->level ("info");
40	or package groups.
41		48
		49	The design goal behind this module was to keep it simple (and small),
		50	but make it powerful enough to be potentially useful for any module, and
		51	extensive enough for the most common tasks, such as logging to multiple
		52	targets, or being able to log into a database.
		53
		54	The amount of documentation might indicate otherwise, but the module is
		55	still just below 300 lines of code.
		56
		57	=head1 LOGGING LEVELS
		58
		59	Logging levels in this module range from C<1> (highest priority) to C<9>
		60	(lowest priority). Note that the lowest numerical value is the highest
		61	priority, so when this document says "higher priority" it means "lower
		62	numerical value".
		63
		64	Instead of specifying levels by name you can also specify them by aliases:
		65
		66	LVL NAME SYSLOG PERL NOTE
		67	1 fatal emerg exit aborts program!
		68	2 alert
		69	3 critical crit
		70	4 error err die
		71	5 warn warning
		72	6 note notice
		73	7 info
		74	8 debug
		75	9 trace
		76
		77	As you can see, some logging levels have multiple aliases - the first one
		78	is the "official" name, the second one the "syslog" name (if it differs)
		79	and the third one the "perl" name, suggesting that you log C<die> messages
		80	at C<error> priority.
		81
		82	You can normally only log a single message at highest priority level
		83	(C<1>, C<fatal>), because logging a fatal message will also quit the
		84	program - so use it sparingly :)
		85
		86	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		87	or C<all> - these are only valid in the methods they are documented for.
		88
42	=head1 LOG FUNCTIONS	89	=head1 LOGGING FUNCTIONS
43		90
44	These functions allow you to log messages. They always use the caller's	91	These functions allow you to log messages. They always use the caller's
45	package as a "logging module/source". Also, the main logging function is	92	package as a "logging context". Also, the main logging function C<log> is
46	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	93	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
47	loaded.	94	loaded.
48		95
49	=over 4	96	=over 4
50		97
…		…
55	use Carp ();	102	use Carp ();
56	use POSIX ();	103	use POSIX ();
57		104
58	use AnyEvent (); BEGIN { AnyEvent::common_sense }	105	use AnyEvent (); BEGIN { AnyEvent::common_sense }
59	use AnyEvent::Util ();	106	use AnyEvent::Util ();
		107
		108	our $VERSION = $AnyEvent::VERSION;
		109
		110	our ($COLLECT, $FILTER, $LOG);
60		111
61	our ($now_int, $now_str1, $now_str2);	112	our ($now_int, $now_str1, $now_str2);
62		113
63	# Format Time, not public - yet?	114	# Format Time, not public - yet?
64	sub ft($) {	115	sub ft($) {
…		…
69	if $now_int != $i;	120	if $now_int != $i;
70		121
71	"$now_str1$f$now_str2"	122	"$now_str1$f$now_str2"
72	}	123	}
73		124
74	our %CTX; # all logging contexts	125	our %CTX; # all package contexts
75
76	my $default_log_cb = sub { 0 };
77		126
78	# creates a default package context object for the given package	127	# creates a default package context object for the given package
79	sub _pkg_ctx($) {	128	sub _pkg_ctx($) {
80	my $ctx = bless [$_[0], 0, {}, $default_log_cb], "AnyEvent::Log::Ctx";	129	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
81		130
82	# link "parent" package	131	# link "parent" package
83	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "";	132	my $parent = $_[0] =~ /^(.+)::/
		133	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		134	: $COLLECT;
84		135
85	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
86	$ctx->[2]{$pkg+0} = $pkg;	136	$ctx->[2]{$parent+0} = $parent;
87		137
88	$ctx	138	$ctx
89	}	139	}
90		140
91	=item AnyEvent::Log::log $level, $msg[, @args]	141	=item AnyEvent::Log::log $level, $msg[, @args]
92		142
93	Requests logging of the given C<$msg> with the given log level (1..9).	143	Requests logging of the given C<$msg> with the given log level.
94	You can also use the following strings as log level: C<fatal> (1),
95	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
96	C<info> (7), C<debug> (8), C<trace> (9).
97		144
98	For C<fatal> log levels, the program will abort.	145	For C<fatal> log levels, the program will abort.
99		146
100	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	147	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
101	C<$msg> is interpreted as an sprintf format string.	148	C<$msg> is interpreted as an sprintf format string.
…		…
114	Note that you can (and should) call this function as C<AnyEvent::log> or	161	Note that you can (and should) call this function as C<AnyEvent::log> or
115	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	162	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
116	need any additional functionality), as those functions will load the	163	need any additional functionality), as those functions will load the
117	logging module on demand only. They are also much shorter to write.	164	logging module on demand only. They are also much shorter to write.
118		165
119	Also, if you otpionally generate a lot of debug messages (such as when	166	Also, if you optionally generate a lot of debug messages (such as when
120	tracing some code), you should look into using a logger callback and a	167	tracing some code), you should look into using a logger callback and a
121	boolean enabler (see C<logger>, below).	168	boolean enabler (see C<logger>, below).
122		169
123	Example: log something at error level.	170	Example: log something at error level.
124		171
…		…
134		181
135	=cut	182	=cut
136		183
137	# also allow syslog equivalent names	184	# also allow syslog equivalent names
138	our %STR2LEVEL = (	185	our %STR2LEVEL = (
139	fatal => 1, emerg => 1,	186	fatal => 1, emerg => 1, exit => 1,
140	alert => 2,	187	alert => 2,
141	critical => 3, crit => 3,	188	critical => 3, crit => 3,
142	error => 4, err => 4,	189	error => 4, err => 4, die => 4,
143	warn => 5, warning => 5,	190	warn => 5, warning => 5,
144	note => 6, notice => 6,	191	note => 6, notice => 6,
145	info => 7,	192	info => 7,
146	debug => 8,	193	debug => 8,
147	trace => 9,	194	trace => 9,
148	);	195	);
149		196
150	sub now () { time }	197	sub now () { time }
		198
151	AnyEvent::post_detect {	199	AnyEvent::post_detect {
152	*now = \&AE::now;	200	*now = \&AE::now;
153	};	201	};
154		202
155	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	203	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
156		204
157	# time, ctx, level, msg	205	# time, ctx, level, msg
158	sub _format($$$$) {	206	sub _format($$$$) {
159	my $pfx = ft $_[0];	207	my $ts = ft $_[0];
		208	my $ct = " ";
160		209
161	join "",	210	my @res;
162	map "$pfx $_\n",	211
163	split /\n/,
164	sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]	212	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		213	push @res, "$ts$ct$_\n";
		214	$ct = " + ";
		215	}
		216
		217	join "", @res
165	}	218	}
166		219
167	sub _log {	220	sub _log {
168	my ($ctx, $level, $format, @args) = @_;	221	my ($ctx, $level, $format, @args) = @_;
169		222
		223	$level = $level > 0 && $level <= 9
		224	? $level+0
170	$level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	225	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
171		226
172	my $mask = 1 << $level;	227	my $mask = 1 << $level;
173	my $now = AE::now;
174		228
175	my (@ctx, $did_format, $fmt);	229	my (%seen, @ctx, $now, $fmt);
176		230
177	do {	231	do
178	if ($ctx->[1] & $mask) {	232	{
		233	# skip if masked
		234	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		235	if ($ctx->[3]) {
179	# logging target found	236	# logging target found
180		237
181	# get raw message	238	# now get raw message, unless we have it already
182	unless ($did_format) {	239	unless ($now) {
183	$format = $format->() if ref $format;	240	$format = $format->() if ref $format;
184	$format = sprintf $format, @args if @args;	241	$format = sprintf $format, @args if @args;
185	$format =~ s/\n$//;	242	$format =~ s/\n$//;
186	$did_format = 1;	243	$now = AE::now;
187	};	244	};
188		245
189	# format msg	246	# format msg
190	my $str = $ctx->[4]	247	my $str = $ctx->[4]
191	? $ctx->[4]($now, $_[0], $level, $format)	248	? $ctx->[4]($now, $_[0], $level, $format)
192	: $fmt \|\|= _format $now, $_[0], $level, $format;	249	: $fmt \|\|= _format $now, $_[0], $level, $format;
193		250
194	$ctx->[3]($str)	251	$ctx->[3]($str)
195	and next;	252	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		253	} else {
		254	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		255	}
		256	}
196	}	257	}
197
198	# not consume - push parent contexts
199	push @ctx, values %{ $ctx->[2] };
200	} while $ctx = pop @ctx;	258	while $ctx = pop @ctx;
201		259
202	exit 1 if $level <= 1;	260	exit 1 if $level <= 1;
203	}	261	}
204		262
205	sub log($$;@) {	263	sub log($$;@) {
…		…
246	# and later in your program	304	# and later in your program
247	$debug_log->("yo, stuff here") if $debug;	305	$debug_log->("yo, stuff here") if $debug;
248		306
249	$debug and $debug_log->("123");	307	$debug and $debug_log->("123");
250		308
251	Note: currently the enabled var is always true - that will be fixed in a
252	future version :)
253
254	=cut	309	=cut
255		310
256	our %LOGGER;	311	our %LOGGER;
257		312
258	# re-assess logging status for all loggers	313	# re-assess logging status for all loggers
259	sub _reassess {	314	sub _reassess {
		315	local $SIG{__DIE__};
		316	my $die = sub { die };
		317
260	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	318	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
261	my ($ctx, $level, $renabled) = @$_;	319	my ($ctx, $level, $renabled) = @$_;
262		320
263	# to detetc whether a message would be logged, we # actually	321	# to detect whether a message would be logged, we actually
264	# try to log one and die. this isn't # fast, but we can be	322	# try to log one and die. this isn't fast, but we can be
265	# sure that the logging decision is correct :)	323	# sure that the logging decision is correct :)
266		324
267	$$renabled = !eval {	325	$$renabled = !eval {
268	local $SIG{__DIE__};
269
270	_log $ctx, $level, sub { die };	326	_log $ctx, $level, $die;
271		327
272	1	328	1
273	};	329	};
274
275	$$renabled = 1; # TODO
276	}	330	}
277	}	331	}
278		332
279	sub _logger($;$) {	333	sub _logger {
280	my ($ctx, $level, $renabled) = @_;	334	my ($ctx, $level, $renabled) = @_;
281
282	$renabled \|\|= \my $enabled;
283		335
284	$$renabled = 1;	336	$$renabled = 1;
285		337
286	my $logger = [$ctx, $level, $renabled];	338	my $logger = [$ctx, $level, $renabled];
287		339
…		…
306	_logger	358	_logger
307	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	359	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
308	@_	360	@_
309	}	361	}
310		362
311	#TODO
312
313	=back	363	=back
314		364
315	=head1 CONFIGURATION FUNCTIONALITY	365	=head1 LOGGING CONTEXTS
316		366
317	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	367	This module associates every log message with a so-called I<logging
		368	context>, based on the package of the caller. Every perl package has its
		369	own logging context.
318		370
319	#TODO: wahst a context	371	A logging context has three major responsibilities: filtering, logging and
320	#TODO	372	propagating the message.
		373
		374	For the first purpose, filtering, each context has a set of logging
		375	levels, called the log level mask. Messages not in the set will be ignored
		376	by this context (masked).
		377
		378	For logging, the context stores a formatting callback (which takes the
		379	timestamp, context, level and string message and formats it in the way
		380	it should be logged) and a logging callback (which is responsible for
		381	actually logging the formatted message and telling C<AnyEvent::Log>
		382	whether it has consumed the message, or whether it should be propagated).
		383
		384	For propagation, a context can have any number of attached I<slave
		385	contexts>. Any message that is neither masked by the logging mask nor
		386	masked by the logging callback returning true will be passed to all slave
		387	contexts.
		388
		389	Each call to a logging function will log the message at most once per
		390	context, so it does not matter (much) if there are cycles or if the
		391	message can arrive at the same context via multiple paths.
		392
		393	=head2 DEFAULTS
		394
		395	By default, all logging contexts have an full set of log levels ("all"), a
		396	disabled logging callback and the default formatting callback.
		397
		398	Package contexts have the package name as logging title by default.
		399
		400	They have exactly one slave - the context of the "parent" package. The
		401	parent package is simply defined to be the package name without the last
		402	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		403	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		404	exception of the rule - just like the "parent" of any single-component
		405	package name in Perl is C<main>, the default slave of any top-level
		406	package context is C<$AnyEvent::Log::COLLECT>.
		407
		408	Since perl packages form only an approximate hierarchy, this slave
		409	context can of course be removed.
		410
		411	All other (anonymous) contexts have no slaves and an empty title by
		412	default.
		413
		414	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
		415	context that simply logs everything via C<warn>, without propagating
		416	anything anywhere by default. The purpose of this context is to provide
		417	a convenient place to override the global logging target or to attach
		418	additional log targets. It's not meant for filtering.
		419
		420	It then creates the C<$AnyEvent::Log::FILTER> context whose
		421	purpose is to suppress all messages with priority higher
		422	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		423	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		424	is to simply provide filtering according to some global log level.
		425
		426	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		427	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		428	leaves it at default config. Its purpose is simply to collect all log
		429	messages system-wide.
		430
		431	The hierarchy is then:
		432
		433	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		434
		435	The effect of all this is that log messages, by default, wander up to the
		436	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		437	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		438	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		439	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
		440
		441	This makes it easy to set a global logging level (by modifying $FILTER),
		442	but still allow other contexts to send, for example, their debug and trace
		443	messages to the $LOG target despite the global logging level, or to attach
		444	additional log targets that log messages, regardless of the global logging
		445	level.
		446
		447	It also makes it easy to modify the default warn-logger ($LOG) to
		448	something that logs to a file, or to attach additional logging targets
		449	(such as loggign to a file) by attaching it to $FILTER.
		450
		451	=head2 CREATING/FINDING/DESTROYING CONTEXTS
321		452
322	=over 4	453	=over 4
323		454
324	=item $ctx = AnyEvent::Log::ctx [$pkg]	455	=item $ctx = AnyEvent::Log::ctx [$pkg]
325		456
326	Returns a I<config> object for the given package name.	457	This function creates or returns a logging context (which is an object).
327		458
328	If no package name is given, returns the context for the current perl	459	If a package name is given, then the context for that packlage is
		460	returned. If it is called without any arguments, then the context for the
329	package (i.e. the same context as a C<AE::log> call would use).	461	callers package is returned (i.e. the same context as a C<AE::log> call
		462	would use).
330		463
331	If C<undef> is given, then it creates a new anonymous context that is not	464	If C<undef> is given, then it creates a new anonymous context that is not
332	tied to any package and is destroyed when no longer referenced.	465	tied to any package and is destroyed when no longer referenced.
333		466
334	=cut	467	=cut
…		…
338		471
339	ref $pkg	472	ref $pkg
340	? $pkg	473	? $pkg
341	: defined $pkg	474	: defined $pkg
342	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg	475	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
343	: bless [undef, 0, undef, $default_log_cb], "AnyEvent::Log::Ctx"	476	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
344	}	477	}
345		478
346	# create default root context	479	=item AnyEvent::Log::reset
347	{	480
348	my $root = ctx undef;	481	Resets all package contexts and recreates the default hierarchy if
349	$root->[0] = "";	482	necessary, i.e. resets the logging subsystem to defaults, as much as
350	$root->title ("default");	483	possible. This process keeps references to contexts held by other parts of
351	$root->level ($AnyEvent::VERBOSE);	484	the program intact.
		485
		486	This can be used to implement config-file (re-)loading: before loading a
		487	configuration, reset all contexts.
		488
		489	=cut
		490
		491	sub reset {
		492	# hard to kill complex data structures
		493	# we recreate all package loggers and reset the hierarchy
		494	while (my ($k, $v) = each %CTX) {
		495	@$v = ($k, (1 << 10) - 1 - 1, { });
		496
		497	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log);
		498	}
		499
		500	$LOG->slaves;
		501	$LOG->title ('$AnyEvent::Log::LOG');
352	$root->log_cb (sub {	502	$LOG->log_cb (sub {
353	print STDERR shift;	503	warn shift;
354	0	504	0
355	});	505	});
356	$CTX{""} = $root;	506
		507	$FILTER->slaves ($LOG);
		508	$FILTER->title ('$AnyEvent::Log::FILTER');
		509	$FILTER->level ($AnyEvent::VERBOSE);
		510
		511	$COLLECT->slaves ($FILTER);
		512	$COLLECT->title ('$AnyEvent::Log::FILTER');
		513
		514	_reassess;
357	}	515	}
		516
		517	# create the default logger contexts
		518	$LOG = ctx undef;
		519	$FILTER = ctx undef;
		520	$COLLECT = ctx undef;
		521
		522	AnyEvent::Log::reset;
		523
		524	# hello, CPAN, please catch me
		525	package AnyEvent::Log::LOG;
		526	package AE::Log::LOG;
		527	package AnyEvent::Log::FILTER;
		528	package AE::Log::FILTER;
		529	package AnyEvent::Log::COLLECT;
		530	package AE::Log::COLLECT;
358		531
359	package AnyEvent::Log::Ctx;	532	package AnyEvent::Log::Ctx;
360		533
361	# 0 1 2 3 4	534	# 0 1 2 3 4
362	# [$title, $level, %$parents, &$logcb, &$fmtcb]	535	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		536
		537	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		538
		539	This is a convenience constructor that makes it simpler to construct
		540	anonymous logging contexts.
		541
		542	Each key-value pair results in an invocation of the method of the same
		543	name as the key with the value as parameter, unless the value is an
		544	arrayref, in which case it calls the method with the contents of the
		545	array. The methods are called in the same order as specified.
		546
		547	Example: create a new logging context and set both the default logging
		548	level, some slave contexts and a logging callback.
		549
		550	$ctx = new AnyEvent::Log::Ctx
		551	title => "dubious messages",
		552	level => "error",
		553	log_cb => sub { print STDOUT shift; 0 },
		554	slaves => [$ctx1, $ctx, $ctx2],
		555	;
		556
		557	=back
		558
		559	=cut
		560
		561	sub new {
		562	my $class = shift;
		563
		564	my $ctx = AnyEvent::Log::ctx undef;
		565
		566	while (@_) {
		567	my ($k, $v) = splice @_, 0, 2;
		568	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		569	}
		570
		571	bless $ctx, $class # do we really support subclassing, hmm?
		572	}
		573
		574
		575	=head2 CONFIGURING A LOG CONTEXT
		576
		577	The following methods can be used to configure the logging context.
		578
		579	=over 4
363		580
364	=item $ctx->title ([$new_title])	581	=item $ctx->title ([$new_title])
365		582
366	Returns the title of the logging context - this is the package name, for	583	Returns the title of the logging context - this is the package name, for
367	package contexts, and a user defined string for all others.	584	package contexts, and a user defined string for all others.
…		…
373	sub title {	590	sub title {
374	$_[0][0] = $_[1] if @_ > 1;	591	$_[0][0] = $_[1] if @_ > 1;
375	$_[0][0]	592	$_[0][0]
376	}	593	}
377		594
		595	=back
		596
		597	=head3 LOGGING LEVELS
		598
		599	The following methods deal with the logging level set associated with the
		600	log context.
		601
		602	The most common method to use is probably C<< $ctx->level ($level) >>,
		603	which configures the specified and any higher priority levels.
		604
		605	All functions which accept a list of levels also accept the special string
		606	C<all> which expands to all logging levels.
		607
		608	=over 4
		609
378	=item $ctx->levels ($level[, $level...)	610	=item $ctx->levels ($level[, $level...)
379		611
380	Enables logging fot the given levels and disables it for all others.	612	Enables logging for the given levels and disables it for all others.
381		613
382	=item $ctx->level ($level)	614	=item $ctx->level ($level)
383		615
384	Enables logging for the given level and all lower level (higher priority)	616	Enables logging for the given level and all lower level (higher priority)
385	ones. Specifying a level of C<0> or C<off> disables all logging for this	617	ones. In addition to normal logging levels, specifying a level of C<0> or
386	level.	618	C<off> disables all logging for this level.
387		619
388	Example: log warnings, errors and higher priority messages.	620	Example: log warnings, errors and higher priority messages.
389		621
390	$ctx->level ("warn");	622	$ctx->level ("warn");
391	$ctx->level (5); # same thing, just numeric	623	$ctx->level (5); # same thing, just numeric
…		…
399	Disables logging for the given levels, leaving all others unchanged.	631	Disables logging for the given levels, leaving all others unchanged.
400		632
401	=cut	633	=cut
402		634
403	sub _lvl_lst {	635	sub _lvl_lst {
		636	map {
		637	$_ > 0 && $_ <= 9 ? $_+0
		638	: $_ eq "all" ? (1 .. 9)
404	map { $_ > 0 && $_ <= 9 ? $_+0 : $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught" }	639	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
405	@_	640	} @_
406	}	641	}
407		642
408	our $NOP_CB = sub { 0 };	643	our $NOP_CB = sub { 0 };
409		644
410	sub levels {	645	sub levels {
…		…
415	AnyEvent::Log::_reassess;	650	AnyEvent::Log::_reassess;
416	}	651	}
417		652
418	sub level {	653	sub level {
419	my $ctx = shift;	654	my $ctx = shift;
420	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[0];	655	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		656
421	$ctx->[1] = ((1 << $lvl) - 1) << 1;	657	$ctx->[1] = ((1 << $lvl) - 1) << 1;
422	AnyEvent::Log::_reassess;	658	AnyEvent::Log::_reassess;
423	}	659	}
424		660
425	sub enable {	661	sub enable {
…		…
434	$ctx->[1] &= ~(1 << $_)	670	$ctx->[1] &= ~(1 << $_)
435	for &_lvl_lst;	671	for &_lvl_lst;
436	AnyEvent::Log::_reassess;	672	AnyEvent::Log::_reassess;
437	}	673	}
438		674
		675	=back
		676
		677	=head3 SLAVE CONTEXTS
		678
		679	The following methods attach and detach another logging context to a
		680	logging context.
		681
		682	Log messages are propagated to all slave contexts, unless the logging
		683	callback consumes the message.
		684
		685	=over 4
		686
439	=item $ctx->attach ($ctx2[, $ctx3...])	687	=item $ctx->attach ($ctx2[, $ctx3...])
440		688
441	Attaches the given contexts as parents to this context. It is not an error	689	Attaches the given contexts as slaves to this context. It is not an error
442	to add a context twice (the second add will be ignored).	690	to add a context twice (the second add will be ignored).
443		691
444	A context can be specified either as package name or as a context object.	692	A context can be specified either as package name or as a context object.
445		693
446	=item $ctx->detach ($ctx2[, $ctx3...])	694	=item $ctx->detach ($ctx2[, $ctx3...])
447		695
448	Removes the given parents from this context - it's not an error to attempt	696	Removes the given slaves from this context - it's not an error to attempt
449	to remove a context that hasn't been added.	697	to remove a context that hasn't been added.
450		698
451	A context can be specified either as package name or as a context object.	699	A context can be specified either as package name or as a context object.
		700
		701	=item $ctx->slaves ($ctx2[, $ctx3...])
		702
		703	Replaces all slaves attached to this context by the ones given.
452		704
453	=cut	705	=cut
454		706
455	sub attach {	707	sub attach {
456	my $ctx = shift;	708	my $ctx = shift;
…		…
463	my $ctx = shift;	715	my $ctx = shift;
464		716
465	delete $ctx->[2]{$_+0}	717	delete $ctx->[2]{$_+0}
466	for map { AnyEvent::Log::ctx $_ } @_;	718	for map { AnyEvent::Log::ctx $_ } @_;
467	}	719	}
		720
		721	sub slaves {
		722	undef $_[0][2];
		723	&attach;
		724	}
		725
		726	=back
		727
		728	=head3 LOG TARGETS
		729
		730	The following methods configure how the logging context actually does
		731	the logging (which consists of formatting the message and printing it or
		732	whatever it wants to do with it).
		733
		734	=over 4
468		735
469	=item $ctx->log_cb ($cb->($str))	736	=item $ctx->log_cb ($cb->($str))
470		737
471	Replaces the logging callback on the context (C<undef> disables the	738	Replaces the logging callback on the context (C<undef> disables the
472	logging callback).	739	logging callback).
…		…
475	(see C<fmt_cb> below) - normally simple text strings that end with a	742	(see C<fmt_cb> below) - normally simple text strings that end with a
476	newline (and are possibly multiline themselves).	743	newline (and are possibly multiline themselves).
477		744
478	It also has to return true iff it has consumed the log message, and false	745	It also has to return true iff it has consumed the log message, and false
479	if it hasn't. Consuming a message means that it will not be sent to any	746	if it hasn't. Consuming a message means that it will not be sent to any
480	parent context. When in doubt, return C<0> from your logging callback.	747	slave context. When in doubt, return C<0> from your logging callback.
481		748
482	Example: a very simple logging callback, simply dump the message to STDOUT	749	Example: a very simple logging callback, simply dump the message to STDOUT
483	and do not consume it.	750	and do not consume it.
484		751
485	$ctx->log_cb (sub { print STDERR shift; 0 });	752	$ctx->log_cb (sub { print STDERR shift; 0 });
486		753
		754	You can filter messages by having a log callback that simply returns C<1>
		755	and does not do anything with the message, but this counts as "message
		756	being logged" and might not be very efficient.
		757
		758	Example: propagate all messages except for log levels "debug" and
		759	"trace". The messages will still be generated, though, which can slow down
		760	your program.
		761
		762	$ctx->levels ("debug", "trace");
		763	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		764
		765	=item $ctx->log_to_file ($path)
		766
		767	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		768
		769	=item $ctx->log_to_path ($path)
		770
		771	Same as C<< ->log_to_file >>, but opens the file for each message. This
		772	is much slower, but allows you to change/move/rename/delete the file at
		773	basically any time.
		774
487	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	775	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))
488		776
489	Replaces the fornatting callback on the cobntext (C<undef> restores the	777	Replaces the formatting callback on the context (C<undef> restores the
490	default formatter).	778	default formatter).
491		779
492	The callback is passed the (possibly fractional) timestamp, the original	780	The callback is passed the (possibly fractional) timestamp, the original
493	logging context, the (numeric) logging level and the raw message string and needs to	781	logging context, the (numeric) logging level and the raw message string
494	return a formatted log message. In most cases this will be a string, but	782	and needs to return a formatted log message. In most cases this will be a
495	it could just as well be an array reference that just stores the values.	783	string, but it could just as well be an array reference that just stores
		784	the values.
		785
		786	If, for some reaosn, you want to use C<caller> to find out more baout the
		787	logger then you should walk up the call stack until you are no longer
		788	inside the C<AnyEvent::Log> package.
496		789
497	Example: format just the raw message, with numeric log level in angle	790	Example: format just the raw message, with numeric log level in angle
498	brackets.	791	brackets.
499		792
500	$ctx->fmt_cb (sub {	793	$ctx->fmt_cb (sub {
…		…
522	=cut	815	=cut
523		816
524	sub log_cb {	817	sub log_cb {
525	my ($ctx, $cb) = @_;	818	my ($ctx, $cb) = @_;
526		819
527	$ctx->[3] = $cb \|\| $default_log_cb;	820	$ctx->[3] = $cb;
528	}	821	}
529		822
530	sub fmt_cb {	823	sub fmt_cb {
531	my ($ctx, $cb) = @_;	824	my ($ctx, $cb) = @_;
532		825
533	$ctx->[4] = $cb;	826	$ctx->[4] = $cb;
534	}	827	}
535		828
		829	sub log_to_file {
		830	my ($ctx, $path) = @_;
		831
		832	open my $fh, ">>", $path
		833	or die "$path: $!";
		834
		835	$ctx->log_cb (sub {
		836	syswrite $fh, shift;
		837	0
		838	});
		839	}
		840
		841	sub log_to_file {
		842	my ($ctx, $path) = @_;
		843
		844	$ctx->log_cb (sub {
		845	open my $fh, ">>", $path
		846	or die "$path: $!";
		847
		848	syswrite $fh, shift;
		849	0
		850	});
		851	}
		852
		853	=back
		854
		855	=head3 MESSAGE LOGGING
		856
		857	These methods allow you to log messages directly to a context, without
		858	going via your package context.
		859
		860	=over 4
		861
536	=item $ctx->log ($level, $msg[, @params])	862	=item $ctx->log ($level, $msg[, @params])
537		863
538	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	864	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
539		865
540	=item $logger = $ctx->logger ($level[, \$enabled])	866	=item $logger = $ctx->logger ($level[, \$enabled])
…		…
549		875
550	1;	876	1;
551		877
552	=back	878	=back
553		879
		880	=head1 EXAMPLES
		881
		882	This section shows some common configurations.
		883
		884	=over 4
		885
		886	=item Setting the global logging level.
		887
		888	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		889	running your program, or modify the log level of the root context:
		890
		891	PERL_ANYEVENT_VERBOSE=5 ./myprog
		892
		893	$AnyEvent::Log::FILTER->level ("warn");
		894
		895	=item Append all messages to a file instead of sending them to STDERR.
		896
		897	This is affected by the global logging level.
		898
		899	$AnyEvent::Log::LOG->log_to_file ($path); (sub {
		900
		901	=item Write all messages with priority C<error> and higher to a file.
		902
		903	This writes them only when the global logging level allows it, because
		904	it is attached to the default context which is invoked I<after> global
		905	filtering.
		906
		907	$AnyEvent::Log::FILTER->attach
		908	new AnyEvent::Log::Ctx log_to_file => $path);
		909
		910	This writes them regardless of the global logging level, because it is
		911	attached to the toplevel context, which receives all messages I<before>
		912	the global filtering.
		913
		914	$AnyEvent::Log::COLLECT->attach (
		915	new AnyEvent::Log::Ctx log_to_file => $path);
		916
		917	In both cases, messages are still written to STDERR.
		918
		919	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		920
		921	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		922	context - this simply circumvents the global filtering for trace messages.
		923
		924	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		925	$debug->attach ($AnyEvent::Log::LOG);
		926
		927	This of course works for any package, not just L<AnyEvent::Debug>, but
		928	assumes the log level for AnyEvent::Debug hasn't been changed from the
		929	default.
		930
		931	=back
		932
554	=head1 AUTHOR	933	=head1 AUTHOR
555		934
556	Marc Lehmann <schmorp@schmorp.de>	935	Marc Lehmann <schmorp@schmorp.de>
557	http://home.schmorp.de/	936	http://home.schmorp.de/
558		937

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.8 by root, Fri Aug 19 19:20:36 2011 UTC vs. Revision 1.18 by root, Sat Aug 20 15:57:35 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
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Revision 1.18 by root, Sat Aug 20 15:57:35 2011 UTC