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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.5 by root, Wed Aug 17 22:03:03 2011 UTC vs.
Revision 1.16 by root, Sat Aug 20 02:19:18 2011 UTC

…		…
2		2
3	AnyEvent::Log - simple logging "framework"	3	AnyEvent::Log - simple logging "framework"
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
		7	# simple use
		8	use AnyEvent;
		9
		10	AE::log debug => "hit my knee";
		11	AE::log warn => "it's a bit too hot";
		12	AE::log error => "the flag was false!";
		13	AE::log fatal => "the bit toggled! run!";
		14
		15	# "complex" use
7	use AnyEvent::Log;	16	use AnyEvent::Log;
		17
		18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
		19
		20	$tracer->("i am here") if $trace;
		21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
		22
		23	# configuration
		24
		25	# set logging for this package to errors and higher only
		26	AnyEvent::Log::ctx->level ("error");
		27
		28	# set logging globally to anything below debug
		29	$AnyEvent::Log::Root->level ("notice");
		30
		31	# see also EXAMPLES, below
8		32
9	=head1 DESCRIPTION	33	=head1 DESCRIPTION
10		34
11	This module implements a relatively simple "logging framework". It doesn't	35	This module implements a relatively simple "logging framework". It doesn't
12	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
13	AnyEvent - AnyEvent simply creates logging messages internally, and this	37	AnyEvent - AnyEvent simply creates logging messages internally, and this
14	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
15	using it from other modules as well.	39	using it from other modules as well.
16		40
17	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
18	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
19	before starting your program.#TODO	43	starting your program, or change the logging level at runtime with
		44	something like:
20		45
21	Possible future extensions are to allow custom log targets (where the	46	use AnyEvent;
22	level is an object), log filtering based on package, formatting, aliasing	47	(AnyEvent::Log::ctx "")->level ("info");
23	or package groups.
24		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 240 lines or so.
		56
25	=head1 LOG FUNCTIONS	57	=head1 LOGGING FUNCTIONS
26		58
27	These functions allow you to log messages. They always use the caller's	59	These functions allow you to log messages. They always use the caller's
28	package as a "logging module/source". Also, The main logging function is	60	package as a "logging module/source". Also, the main logging function is
29	easily available as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent>	61	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
30	module is loaded.	62	loaded.
31		63
32	=over 4	64	=over 4
33		65
34	=cut	66	=cut
35		67
…		…
38	use Carp ();	70	use Carp ();
39	use POSIX ();	71	use POSIX ();
40		72
41	use AnyEvent (); BEGIN { AnyEvent::common_sense }	73	use AnyEvent (); BEGIN { AnyEvent::common_sense }
42	use AnyEvent::Util ();	74	use AnyEvent::Util ();
		75
		76	our $VERSION = $AnyEvent::VERSION;
43		77
44	our ($now_int, $now_str1, $now_str2);	78	our ($now_int, $now_str1, $now_str2);
45		79
46	# Format Time, not public - yet?	80	# Format Time, not public - yet?
47	sub ft($) {	81	sub ft($) {
…		…
54	"$now_str1$f$now_str2"	88	"$now_str1$f$now_str2"
55	}	89	}
56		90
57	our %CTX; # all logging contexts	91	our %CTX; # all logging contexts
58		92
		93	# creates a default package context object for the given package
		94	sub _pkg_ctx($) {
		95	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
		96
		97	# link "parent" package
		98	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";
		99
		100	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
		101	$ctx->[2]{$pkg+0} = $pkg;
		102
		103	$ctx
		104	}
		105
59	=item AnyEvent::Log::log $level, $msg[, @args]	106	=item AnyEvent::Log::log $level, $msg[, @args]
60		107
61	Requests logging of the given C<$msg> with the given log level (1..9).	108	Requests logging of the given C<$msg> with the given log level (1..9).
62	You can also use the following strings as log level: C<fatal> (1),	109	You can also use the following strings as log level: C<fatal> (1),
63	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),	110	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
…		…
78		125
79	Whether the given message will be logged depends on the maximum log level	126	Whether the given message will be logged depends on the maximum log level
80	and the caller's package.	127	and the caller's package.
81		128
82	Note that you can (and should) call this function as C<AnyEvent::log> or	129	Note that you can (and should) call this function as C<AnyEvent::log> or
83	C<AE::log>, without C<use>-ing this module if possible, as those functions	130	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
84	will laod the logging module on demand only.	131	need any additional functionality), as those functions will load the
		132	logging module on demand only. They are also much shorter to write.
		133
		134	Also, if you optionally generate a lot of debug messages (such as when
		135	tracing some code), you should look into using a logger callback and a
		136	boolean enabler (see C<logger>, below).
85		137
86	Example: log something at error level.	138	Example: log something at error level.
87		139
88	AE::log error => "something";	140	AE::log error => "something";
89		141
…		…
109	debug => 8,	161	debug => 8,
110	trace => 9,	162	trace => 9,
111	);	163	);
112		164
113	sub now () { time }	165	sub now () { time }
		166
114	AnyEvent::post_detect {	167	AnyEvent::post_detect {
115	*now = \&AE::now;	168	*now = \&AE::now;
116	};	169	};
117		170
118	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	171	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
119		172
		173	# time, ctx, level, msg
		174	sub _format($$$$) {
		175	my $ts = ft $_[0];
		176	my $ct = " ";
		177
		178	my @res;
		179
		180	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		181	push @res, "$ts$ct$_\n";
		182	$ct = " + ";
		183	}
		184
		185	join "", @res
		186	}
		187
120	sub _log {	188	sub _log {
121	my ($pkg, $targ, $msg, @args) = @_;	189	my ($ctx, $level, $format, @args) = @_;
122		190
123	my $level = ref $targ ? die "Can't use reference as logging level (yet)"	191	$level = $level > 0 && $level <= 9
124	: $targ > 0 && $targ <= 9 ? $targ+0	192	? $level+0
125	: $STR2LEVEL{$targ} \|\| Carp::croak "$targ: not a valid logging level, caught";	193	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
126		194
127	#TODO: find actual targets, see if we even have to log	195	my $mask = 1 << $level;
128		196
129	return unless $level <= $AnyEvent::VERBOSE;	197	my (%seen, @ctx, $now, $fmt);
130		198
131	$msg = $msg->() if ref $msg;	199	do
132	$msg = sprintf $msg, @args if @args;	200	{
133	$msg =~ s/\n$//;	201	# skip if masked
		202	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		203	if ($ctx->[3]) {
		204	# logging target found
134		205
135	# now we have a message, log it	206	# now get raw message, unless we have it already
		207	unless ($now) {
		208	$format = $format->() if ref $format;
		209	$format = sprintf $format, @args if @args;
		210	$format =~ s/\n$//;
		211	$now = AE::now;
		212	};
136		213
137	# TODO: writers/processors/filters/formatters?	214	# format msg
		215	my $str = $ctx->[4]
		216	? $ctx->[4]($now, $_[0], $level, $format)
		217	: $fmt \|\|= _format $now, $_[0], $level, $format;
138		218
139	$msg = sprintf "%-5s %s: %s", $LEVEL2STR[$level], $pkg, $msg;	219	$ctx->[3]($str);
140	my $pfx = ft now;	220	}
141		221
142	for (split /\n/, $msg) {	222	# not masked, not consumed - propagate to parent contexts
143	printf STDERR "$pfx $_\n";	223	push @ctx, values %{ $ctx->[2] };
144	$pfx = "\t";	224	}
145	}	225	}
		226	while $ctx = pop @ctx;
146		227
147	exit 1 if $level <= 1;	228	exit 1 if $level <= 1;
148	}	229	}
149		230
150	sub log($$;@) {	231	sub log($$;@) {
151	_log +(caller)[0], @_;	232	_log
		233	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		234	@_;
152	}	235	}
153		236
154	AnyEvent::log = AE::log = \&log;	237	AnyEvent::log = AE::log = \&log;
155		238
156	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	239	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
…		…
189	# and later in your program	272	# and later in your program
190	$debug_log->("yo, stuff here") if $debug;	273	$debug_log->("yo, stuff here") if $debug;
191		274
192	$debug and $debug_log->("123");	275	$debug and $debug_log->("123");
193		276
194	Note: currently the enabled var is always true - that will be fixed in a
195	future version :)
196
197	=cut	277	=cut
198		278
199	our %LOGGER;	279	our %LOGGER;
200		280
201	# re-assess logging status for all loggers	281	# re-assess logging status for all loggers
202	sub _reassess {	282	sub _reassess {
203	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	283	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
204	my ($pkg, $level, $renabled) = @$_;	284	my ($ctx, $level, $renabled) = @$_;
205		285
206	# to detetc whether a message would be logged, we # actually	286	# to detect whether a message would be logged, we # actually
207	# try to log one and die. this isn't # fast, but we can be	287	# try to log one and die. this isn't fast, but we can be
208	# sure that the logging decision is correct :)	288	# sure that the logging decision is correct :)
209		289
210	$$renabled = !eval {	290	$$renabled = !eval {
211	local $SIG{__DIE__};	291	local $SIG{__DIE__};
212		292
213	_log $pkg, $level, sub { die };	293	_log $ctx, $level, sub { die };
214		294
215	1	295	1
216	};	296	};
217		297
218	$$renabled = 1; # TODO	298	$$renabled = 1; # TODO
219	}	299	}
220	}	300	}
221		301
222	sub logger($;$) {	302	sub _logger {
223	my ($level, $renabled) = @_;	303	my ($ctx, $level, $renabled) = @_;
224
225	$renabled \|\|= \my $enabled;
226	my $pkg = (caller)[0];
227		304
228	$$renabled = 1;	305	$$renabled = 1;
229		306
230	my $logger = [$pkg, $level, $renabled];	307	my $logger = [$ctx, $level, $renabled];
231		308
232	$LOGGER{$logger+0} = $logger;	309	$LOGGER{$logger+0} = $logger;
233		310
234	_reassess $logger+0;	311	_reassess $logger+0;
235		312
…		…
239	};	316	};
240		317
241	sub {	318	sub {
242	$guard if 0; # keep guard alive, but don't cause runtime overhead	319	$guard if 0; # keep guard alive, but don't cause runtime overhead
243		320
244	_log $pkg, $level, @_	321	_log $ctx, $level, @_
245	if $$renabled;	322	if $$renabled;
246	}	323	}
247	}	324	}
248		325
249	#TODO	326	sub logger($;$) {
		327	_logger
		328	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		329	@_
		330	}
250		331
251	=back	332	=back
252		333
253	=head1 CONFIGURATION FUNCTIONALITY	334	=head1 LOGGING CONTEXTS
254		335
255	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	336	This module associates every log message with a so-called I<logging
		337	context>, based on the package of the caller. Every perl package has its
		338	own logging context.
		339
		340	A logging context has three major responsibilities: filtering, logging and
		341	propagating the message.
		342
		343	For the first purpose, filtering, each context has a set of logging
		344	levels, called the log level mask. Messages not in the set will be ignored
		345	by this context (masked).
		346
		347	For logging, the context stores a formatting callback (which takes the
		348	timestamp, context, level and string message and formats it in the way
		349	it should be logged) and a logging callback (which is responsible for
		350	actually logging the formatted message and telling C<AnyEvent::Log>
		351	whether it has consumed the message, or whether it should be propagated).
		352
		353	For propagation, a context can have any number of attached I<parent
		354	contexts>. Any message that is neither masked by the logging mask nor
		355	masked by the logging callback returning true will be passed to all parent
		356	contexts.
		357
		358	Each call to a logging function will log the message at most once per
		359	context, so it does not matter (much) if there are cycles or if the
		360	message can arrive at the same context via multiple paths.
		361
		362	=head2 DEFAULTS
		363
		364	By default, all logging contexts have an full set of log levels ("all"), a
		365	disabled logging callback and the default formatting callback.
		366
		367	Package contexts have the package name as logging title by default.
		368
		369	They have exactly one parent - the context of the "parent" package. The
		370	parent package is simply defined to be the package name without the last
		371	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		372	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the
		373	exception of the rule - just like the parent of any package name in
		374	Perl is C<main>, the default parent of any top-level package context is
		375	C<AnyEvent::Log::Top>.
		376
		377	Since perl packages form only an approximate hierarchy, this parent
		378	context can of course be removed.
		379
		380	All other (anonymous) contexts have no parents and an empty title by
		381	default.
		382
		383	When the module is loaded it creates the default context called
		384	C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>),
		385	which simply logs everything via C<warn> and doesn't propagate anything
		386	anywhere by default. The purpose of the default context is to provide
		387	a convenient place to override the global logging target or to attach
		388	additional log targets. It's not meant for filtering.
		389
		390	It then creates the root context called C<AnyEvent::Log::Root> (also
		391	stored in C<$AnyEvent::Log::Root>) and sets its log level set to all
		392	levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It
		393	then attached the default logging context to it. The purpose of the root
		394	context is to simply provide filtering according to some global log level.
		395
		396	Finally it creates the top-level package context called
		397	C<AnyEvent::Log::Top> (also stored in, you might have guessed,
		398	C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
		399	it at default config. It's purpose is simply to collect all log messages
		400	system-wide.
		401
		402	These three special contexts can also be referred to by the
		403	package/context names C<AE::Log::Default>, C<AE::Log::Root> and
		404	C<AE::Log::Top>.
		405
		406	The effect of all this is that log messages, by default, wander up
		407	to the root context where log messages with lower priority then
		408	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the
		409	AnyEvent::Log::Default context to be passed to C<warn>.
		410
		411	Splitting the top level context into three contexts makes it easy to set
		412	a global logging level (by modifying the root context), but still allow
		413	other contexts to log, for example, their debug and trace messages to the
		414	default target despite the global logging level, or to attach additional
		415	log targets that log messages, regardless of the global logging level.
		416
		417	It also makes it easy to replace the default warn-logger by something that
		418	logs to a file, or to attach additional logging targets.
		419
		420	=head2 CREATING/FINDING/DESTROYING CONTEXTS
256		421
257	=over 4	422	=over 4
258		423
259	=item $ctx = AnyEvent::Log::ctx [$pkg]	424	=item $ctx = AnyEvent::Log::ctx [$pkg]
260		425
261	Returns the I<context> object for the given package name (or previously	426	This function creates or returns a logging context (which is an object).
262	created package-less context). If no package name, or C<undef>, is given,	427
263	then it creates a new anonymous context that is not tied to any package.	428	If a package name is given, then the context for that packlage is
		429	returned. If it is called without any arguments, then the context for the
		430	callers package is returned (i.e. the same context as a C<AE::log> call
		431	would use).
		432
		433	If C<undef> is given, then it creates a new anonymous context that is not
		434	tied to any package and is destroyed when no longer referenced.
264		435
265	=cut	436	=cut
266		437
267	sub ctx(;$) {	438	sub ctx(;$) {
268	my $name = shift;	439	my $pkg = @_ ? shift : (caller)[0];
269		440
270	my $ctx = defined $name ? $CTX{$name} : undef;	441	ref $pkg
		442	? $pkg
		443	: defined $pkg
		444	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
		445	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
		446	}
271		447
272	unless ($ctx} {	448	=item AnyEvent::Log::reset
273	$ctx = bless {}, "AnyEvent::Log::Ctx";
274	$name = $ctx+0 unless defined $name;
275	$CTX{
276		449
277	if (defined $name) {	450	Resets all package contexts and recreates the default hierarchy if
278	my $ctx = {};	451	necessary, i.e. resets the logging subsystem to defaults, as much as
279	$CTX{$ctx+0} = $ctx;	452	possible. This process keeps references to contexts held by other parts of
280	} else {	453	the program intact.
281	$CTX{	454
		455	This can be used to implement config-file (re-)loading: before loading a
		456	configuration, reset all contexts.
		457
		458	=cut
		459
		460	sub reset {
		461	# hard to kill complex data structures
		462	# we recreate all package loggers and reset the hierarchy
		463	while (my ($k, $v) = each %CTX) {
		464	@$v = ($k, (1 << 10) - 1 - 1, { });
		465
		466	my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top";
		467	$v->attach ($CTX{$pkg});
282	}	468	}
		469
		470	$AnyEvent::Log::Default->parents;
		471	$AnyEvent::Log::Default->title ("AnyEvent::Log::Default");
		472	$AnyEvent::Log::Default->log_cb (sub {
		473	warn shift;
		474	0
		475	});
		476	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
		477
		478	$AnyEvent::Log::Root->parents ($AnyEvent::Log::Default);
		479	$AnyEvent::Log::Root->title ("AnyEvent::Log::Root");
		480	$AnyEvent::Log::Root->level ($AnyEvent::VERBOSE);
		481	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
		482
		483	$AnyEvent::Log::Top->parents ($AnyEvent::Log::Root);
		484	$AnyEvent::Log::Top->title ("AnyEvent::Log::Top");
		485	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $AnyEvent::Log::Top;
		486
		487	_reassess;
283	}	488	}
		489
		490	# create the default logger contexts
		491	$AnyEvent::Log::Default = ctx undef;
		492	$AnyEvent::Log::Root = ctx undef;
		493	$AnyEvent::Log::Top = ctx undef;
		494
		495	AnyEvent::Log::reset;
		496
		497	# hello, CPAN, please catch me
		498	package AnyEvent::Log::Default;
		499	package AE::Log::Default;
		500	package AnyEvent::Log::Root;
		501	package AE::Log::Root;
		502	package AnyEvent::Log::Top;
		503	package AE::Log::Top;
		504
		505	package AnyEvent::Log::Ctx;
		506
		507	# 0 1 2 3 4
		508	# [$title, $level, %$parents, &$logcb, &$fmtcb]
		509
		510	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		511
		512	This is a convenience constructor that makes it simpler to construct
		513	anonymous logging contexts.
		514
		515	Each key-value pair results in an invocation of the method of the same
		516	name as the key with the value as parameter, unless the value is an
		517	arrayref, in which case it calls the method with the contents of the
		518	array. The methods are called in the same order as specified.
		519
		520	Example: create a new logging context and set both the default logging
		521	level, some parent contexts and a logging callback.
		522
		523	$ctx = new AnyEvent::Log::Ctx
		524	title => "dubious messages",
		525	level => "error",
		526	log_cb => sub { print STDOUT shift; 0 },
		527	parents => [$ctx1, $ctx, $ctx2],
		528	;
		529
		530	=back
		531
		532	=cut
		533
		534	sub new {
		535	my $class = shift;
		536
		537	my $ctx = AnyEvent::Log::ctx undef;
		538
		539	while (@_) {
		540	my ($k, $v) = splice @_, 0, 2;
		541	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		542	}
		543
		544	bless $ctx, $class # do we really support subclassing, hmm?
		545	}
		546
		547
		548	=head2 CONFIGURING A LOG CONTEXT
		549
		550	The following methods can be used to configure the logging context.
		551
		552	=over 4
		553
		554	=item $ctx->title ([$new_title])
		555
		556	Returns the title of the logging context - this is the package name, for
		557	package contexts, and a user defined string for all others.
		558
		559	If C<$new_title> is given, then it replaces the package name or title.
		560
		561	=cut
		562
		563	sub title {
		564	$_[0][0] = $_[1] if @_ > 1;
		565	$_[0][0]
		566	}
		567
		568	=back
		569
		570	=head3 LOGGING LEVELS
		571
		572	The following methods deal with the logging level set associated with the
		573	log context.
		574
		575	The most common method to use is probably C<< $ctx->level ($level) >>,
		576	which configures the specified and any higher priority levels.
		577
		578	All functions which accept a list of levels also accept the special string
		579	C<all> which expands to all logging levels.
		580
		581	=over 4
		582
		583	=item $ctx->levels ($level[, $level...)
		584
		585	Enables logging for the given levels and disables it for all others.
		586
		587	=item $ctx->level ($level)
		588
		589	Enables logging for the given level and all lower level (higher priority)
		590	ones. In addition to normal logging levels, specifying a level of C<0> or
		591	C<off> disables all logging for this level.
		592
		593	Example: log warnings, errors and higher priority messages.
		594
		595	$ctx->level ("warn");
		596	$ctx->level (5); # same thing, just numeric
		597
		598	=item $ctx->enable ($level[, $level...])
		599
		600	Enables logging for the given levels, leaving all others unchanged.
		601
		602	=item $ctx->disable ($level[, $level...])
		603
		604	Disables logging for the given levels, leaving all others unchanged.
		605
		606	=cut
		607
		608	sub _lvl_lst {
		609	map {
		610	$_ > 0 && $_ <= 9 ? $_+0
		611	: $_ eq "all" ? (1 .. 9)
		612	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
		613	} @_
		614	}
		615
		616	our $NOP_CB = sub { 0 };
		617
		618	sub levels {
		619	my $ctx = shift;
		620	$ctx->[1] = 0;
		621	$ctx->[1] \|= 1 << $_
		622	for &_lvl_lst;
		623	AnyEvent::Log::_reassess;
		624	}
		625
		626	sub level {
		627	my $ctx = shift;
		628	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		629
		630	$ctx->[1] = ((1 << $lvl) - 1) << 1;
		631	AnyEvent::Log::_reassess;
		632	}
		633
		634	sub enable {
		635	my $ctx = shift;
		636	$ctx->[1] \|= 1 << $_
		637	for &_lvl_lst;
		638	AnyEvent::Log::_reassess;
		639	}
		640
		641	sub disable {
		642	my $ctx = shift;
		643	$ctx->[1] &= ~(1 << $_)
		644	for &_lvl_lst;
		645	AnyEvent::Log::_reassess;
		646	}
		647
		648	=back
		649
		650	=head3 PARENT CONTEXTS
		651
		652	The following methods attach and detach another logging context to a
		653	logging context.
		654
		655	Log messages are propagated to all parent contexts, unless the logging
		656	callback consumes the message.
		657
		658	=over 4
		659
		660	=item $ctx->attach ($ctx2[, $ctx3...])
		661
		662	Attaches the given contexts as parents to this context. It is not an error
		663	to add a context twice (the second add will be ignored).
		664
		665	A context can be specified either as package name or as a context object.
		666
		667	=item $ctx->detach ($ctx2[, $ctx3...])
		668
		669	Removes the given parents from this context - it's not an error to attempt
		670	to remove a context that hasn't been added.
		671
		672	A context can be specified either as package name or as a context object.
		673
		674	=item $ctx->parents ($ctx2[, $ctx3...])
		675
		676	Replaces all parents attached to this context by the ones given.
		677
		678	=cut
		679
		680	sub attach {
		681	my $ctx = shift;
		682
		683	$ctx->[2]{$_+0} = $_
		684	for map { AnyEvent::Log::ctx $_ } @_;
		685	}
		686
		687	sub detach {
		688	my $ctx = shift;
		689
		690	delete $ctx->[2]{$_+0}
		691	for map { AnyEvent::Log::ctx $_ } @_;
		692	}
		693
		694	sub parents {
		695	undef $_[0][2];
		696	&attach;
		697	}
		698
		699	=back
		700
		701	=head3 MESSAGE LOGGING
		702
		703	The following methods configure how the logging context actually does
		704	the logging (which consists of formatting the message and printing it or
		705	whatever it wants to do with it) and also allows you to log messages
		706	directly to a context, without going via your package context.
		707
		708	=over 4
		709
		710	=item $ctx->log_cb ($cb->($str))
		711
		712	Replaces the logging callback on the context (C<undef> disables the
		713	logging callback).
		714
		715	The logging callback is responsible for handling formatted log messages
		716	(see C<fmt_cb> below) - normally simple text strings that end with a
		717	newline (and are possibly multiline themselves).
		718
		719	It also has to return true iff it has consumed the log message, and false
		720	if it hasn't. Consuming a message means that it will not be sent to any
		721	parent context. When in doubt, return C<0> from your logging callback.
		722
		723	Example: a very simple logging callback, simply dump the message to STDOUT
		724	and do not consume it.
		725
		726	$ctx->log_cb (sub { print STDERR shift; 0 });
		727
		728	You can filter messages by having a log callback that simply returns C<1>
		729	and does not do anything with the message, but this counts as "message
		730	being logged" and might not be very efficient.
		731
		732	Example: propagate all messages except for log levels "debug" and
		733	"trace". The messages will still be generated, though, which can slow down
		734	your program.
		735
		736	$ctx->levels ("debug", "trace");
		737	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		738
		739	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))
		740
		741	Replaces the formatting callback on the context (C<undef> restores the
		742	default formatter).
		743
		744	The callback is passed the (possibly fractional) timestamp, the original
		745	logging context, the (numeric) logging level and the raw message string and needs to
		746	return a formatted log message. In most cases this will be a string, but
		747	it could just as well be an array reference that just stores the values.
		748
		749	Example: format just the raw message, with numeric log level in angle
		750	brackets.
		751
		752	$ctx->fmt_cb (sub {
		753	my ($time, $ctx, $lvl, $msg) = @_;
		754
		755	"<$lvl>$msg\n"
		756	});
		757
		758	Example: return an array reference with just the log values, and use
		759	C<PApp::SQL::sql_exec> to store the emssage in a database.
		760
		761	$ctx->fmt_cb (sub { \@_ });
		762	$ctx->log_cb (sub {
		763	my ($msg) = @_;
		764
		765	sql_exec "insert into log (when, subsys, prio, msg) values (?, ?, ?, ?)",
		766	$msg->[0] + 0,
		767	"$msg->[1]",
		768	$msg->[2] + 0,
		769	"$msg->[3]";
		770
		771	0
		772	});
		773
		774	=cut
		775
		776	sub log_cb {
		777	my ($ctx, $cb) = @_;
		778
		779	$ctx->[3] = $cb;
		780	}
		781
		782	sub fmt_cb {
		783	my ($ctx, $cb) = @_;
		784
		785	$ctx->[4] = $cb;
		786	}
		787
		788	=item $ctx->log ($level, $msg[, @params])
		789
		790	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		791
		792	=item $logger = $ctx->logger ($level[, \$enabled])
		793
		794	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		795	context.
		796
		797	=cut
		798
		799	*log = \&AnyEvent::Log::_log;
		800	*logger = \&AnyEvent::Log::_logger;
284		801
285	1;	802	1;
		803
		804	=back
		805
		806	=head1 EXAMPLES
		807
		808	This section shows some common configurations.
		809
		810	=over 4
		811
		812	=item Setting the global logging level.
		813
		814	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		815	running your program, or modify the log level of the root context:
		816
		817	PERL_ANYEVENT_VERBOSE=5 ./myprog
		818
		819	$AnyEvent::Log::Root->level ("warn");
		820
		821	=item Append all messages to a file instead of sending them to STDERR.
		822
		823	This is affected by the global logging level.
		824
		825	open my $fh, ">>", $path
		826	or die "$path: $!";
		827
		828	$AnyEvent::Log::Default->log_cb (sub {
		829	syswrite $fh, shift;
		830	0
		831	});
		832
		833	=item Write all messages with priority C<error> and higher to a file.
		834
		835	This writes them only when the global logging level allows it, because
		836	it is attached to the default context which is invoked I<after> global
		837	filtering.
		838
		839	open my $fh, ">>", $path
		840	or die "$path: $!";
		841
		842	$AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx
		843	log_cb => sub { syswrite $fh, shift; 0 });
		844
		845	This writes them regardless of the global logging level, because it is
		846	attached to the toplevel context, which receives all messages I<before>
		847	the global filtering.
		848
		849	$AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx
		850	log_cb => sub { syswrite $fh, shift; 0 });
		851
		852	In both cases, messages are still written to STDOUT.
		853
		854	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		855
		856	Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug>
		857	context and increase the C<AnyEvent::Debug> logging level - this simply
		858	circumvents the global filtering for trace messages.
		859
		860	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		861	$debug->attach ($AnyEvent::Log::Default);
		862	$debug->levels ("trace"); # not "level"!
		863
		864	This of course works for any package.
286		865
287	=back	866	=back
288		867
289	=head1 AUTHOR	868	=head1 AUTHOR
290		869

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.5 by root, Wed Aug 17 22:03:03 2011 UTC vs. Revision 1.16 by root, Sat Aug 20 02:19:18 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
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Revision 1.16 by root, Sat Aug 20 02:19:18 2011 UTC