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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.7 by root, Thu Aug 18 18:02:11 2011 UTC vs.
Revision 1.11 by root, Sat Aug 20 01:03:09 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 maximum
		26	AnyEvent::Log::ctx->level ("all");
		27
		28	# set logging globally to anything below debug
		29	(AnyEvent::Log::ctx "")->level ("notice");
		30
		31	# see also EXAMPLES, below
		32
		33	# disable logging for package "AnyEvent" and all packages below it
		34	AnyEvent->AnyEvent::Log::ctx->level (0);
		35
		36	# log everything below debug to a file, for the whole program
		37	my $ctx = AnyEvent::Log::ctx;
		38	$ctx->log_cb (sub { print FILE shift; 0 });
		39	(AnyEvent::Log::ctx "")->add ($ctx);
8		40
9	=head1 DESCRIPTION	41	=head1 DESCRIPTION
10		42
11	This module implements a relatively simple "logging framework". It doesn't	43	This module implements a relatively simple "logging framework". It doesn't
12	attempt to be "the" logging solution or even "a" logging solution for	44	attempt to be "the" logging solution or even "a" logging solution for
13	AnyEvent - AnyEvent simply creates logging messages internally, and this	45	AnyEvent - AnyEvent simply creates logging messages internally, and this
14	module more or less exposes the mechanism, with some extra spiff to allow	46	module more or less exposes the mechanism, with some extra spiff to allow
15	using it from other modules as well.	47	using it from other modules as well.
16		48
17	Remember that the default verbosity level is C<0>, so nothing will be	49	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	50	logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before
19	before starting your program.#TODO	51	starting your program, or change the logging level at runtime with
		52	something like:
20		53
21	Possible future extensions are to allow custom log targets (where the	54	use AnyEvent;
22	level is an object), log filtering based on package, formatting, aliasing	55	(AnyEvent::Log::ctx "")->level ("info");
23	or package groups.
24		56
		57	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
		59	extensive enough for the most common tasks, such as logging to multiple
		60	targets, or being able to log into a database.
		61
25	=head1 LOG FUNCTIONS	62	=head1 LOGGING FUNCTIONS
26		63
27	These functions allow you to log messages. They always use the caller's	64	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	65	package as a "logging module/source". Also, the main logging function is
29	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	66	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
30	loaded.	67	loaded.
…		…
54	"$now_str1$f$now_str2"	91	"$now_str1$f$now_str2"
55	}	92	}
56		93
57	our %CTX; # all logging contexts	94	our %CTX; # all logging contexts
58		95
		96	# creates a default package context object for the given package
		97	sub _pkg_ctx($) {
		98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
		99
		100	# link "parent" package
		101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";
		102
		103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
		104	$ctx->[2]{$pkg+0} = $pkg;
		105
		106	$ctx
		107	}
		108
59	=item AnyEvent::Log::log $level, $msg[, @args]	109	=item AnyEvent::Log::log $level, $msg[, @args]
60		110
61	Requests logging of the given C<$msg> with the given log level (1..9).	111	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),	112	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),	113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
…		…
78		128
79	Whether the given message will be logged depends on the maximum log level	129	Whether the given message will be logged depends on the maximum log level
80	and the caller's package.	130	and the caller's package.
81		131
82	Note that you can (and should) call this function as C<AnyEvent::log> or	132	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	133	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.	134	need any additional functionality), as those functions will load the
		135	logging module on demand only. They are also much shorter to write.
		136
		137	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
		139	boolean enabler (see C<logger>, below).
85		140
86	Example: log something at error level.	141	Example: log something at error level.
87		142
88	AE::log error => "something";	143	AE::log error => "something";
89		144
…		…
109	debug => 8,	164	debug => 8,
110	trace => 9,	165	trace => 9,
111	);	166	);
112		167
113	sub now () { time }	168	sub now () { time }
		169
114	AnyEvent::post_detect {	170	AnyEvent::post_detect {
115	*now = \&AE::now;	171	*now = \&AE::now;
116	};	172	};
117		173
118	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	174	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
119		175
		176	# time, ctx, level, msg
		177	sub _format($$$$) {
		178	my $ts = ft $_[0];
		179	my $ct = " ";
		180
		181	my @res;
		182
		183	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		184	push @res, "$ts$ct$_\n";
		185	$ct = " + ";
		186	}
		187
		188	join "", @res
		189	}
		190
120	sub _log {	191	sub _log {
121	my ($pkg, $targ, $msg, @args) = @_;	192	my ($ctx, $level, $format, @args) = @_;
122		193
123	my $level = ref $targ ? die "Can't use reference as logging level (yet)"	194	$level = $level > 0 && $level <= 9
124	: $targ > 0 && $targ <= 9 ? $targ+0	195	? $level+0
125	: $STR2LEVEL{$targ} \|\| Carp::croak "$targ: not a valid logging level, caught";	196	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
126		197
127	#TODO: find actual targets, see if we even have to log	198	my $mask = 1 << $level;
128		199
129	return unless $level <= $AnyEvent::VERBOSE;	200	my (%seen, @ctx, $now, $fmt);
130		201
131	$msg = $msg->() if ref $msg;	202	do
132	$msg = sprintf $msg, @args if @args;	203	{
133	$msg =~ s/\n$//;	204	# skip if masked
		205	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		206	if ($ctx->[3]) {
		207	# logging target found
134		208
135	# now we have a message, log it	209	# now get raw message, unless we have it already
		210	unless ($now) {
		211	$format = $format->() if ref $format;
		212	$format = sprintf $format, @args if @args;
		213	$format =~ s/\n$//;
		214	$now = AE::now;
		215	};
136		216
137	# TODO: writers/processors/filters/formatters?	217	# format msg
		218	my $str = $ctx->[4]
		219	? $ctx->[4]($now, $_[0], $level, $format)
		220	: $fmt \|\|= _format $now, $_[0], $level, $format;
138		221
139	$msg = sprintf "%-5s %s: %s", $LEVEL2STR[$level], $pkg, $msg;	222	$ctx->[3]($str);
140	my $pfx = ft now;	223	}
141		224
142	for (split /\n/, $msg) {	225	# not masked, not consumed - propagate to parent contexts
143	printf STDERR "$pfx $_\n";	226	push @ctx, values %{ $ctx->[2] };
144	$pfx = "\t";	227	}
145	}	228	}
		229	while $ctx = pop @ctx;
146		230
147	exit 1 if $level <= 1;	231	exit 1 if $level <= 1;
148	}	232	}
149		233
150	sub log($$;@) {	234	sub log($$;@) {
151	_log +(caller)[0], @_;	235	_log
		236	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		237	@_;
152	}	238	}
153		239
154	AnyEvent::log = AE::log = \&log;	240	AnyEvent::log = AE::log = \&log;
155		241
156	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	242	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
…		…
199	our %LOGGER;	285	our %LOGGER;
200		286
201	# re-assess logging status for all loggers	287	# re-assess logging status for all loggers
202	sub _reassess {	288	sub _reassess {
203	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	289	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
204	my ($pkg, $level, $renabled) = @$_;	290	my ($ctx, $level, $renabled) = @$_;
205		291
206	# to detetc whether a message would be logged, we # actually	292	# to detect whether a message would be logged, we # actually
207	# try to log one and die. this isn't # fast, but we can be	293	# try to log one and die. this isn't fast, but we can be
208	# sure that the logging decision is correct :)	294	# sure that the logging decision is correct :)
209		295
210	$$renabled = !eval {	296	$$renabled = !eval {
211	local $SIG{__DIE__};	297	local $SIG{__DIE__};
212		298
213	_log $pkg, $level, sub { die };	299	_log $ctx, $level, sub { die };
214		300
215	1	301	1
216	};	302	};
217		303
218	$$renabled = 1; # TODO	304	$$renabled = 1; # TODO
219	}	305	}
220	}	306	}
221		307
222	sub logger($;$) {	308	sub _logger($;$) {
223	my ($level, $renabled) = @_;	309	my ($ctx, $level, $renabled) = @_;
224		310
225	$renabled \|\|= \my $enabled;	311	$renabled \|\|= \my $enabled;
226	my $pkg = (caller)[0];
227		312
228	$$renabled = 1;	313	$$renabled = 1;
229		314
230	my $logger = [$pkg, $level, $renabled];	315	my $logger = [$ctx, $level, $renabled];
231		316
232	$LOGGER{$logger+0} = $logger;	317	$LOGGER{$logger+0} = $logger;
233		318
234	_reassess $logger+0;	319	_reassess $logger+0;
235		320
…		…
239	};	324	};
240		325
241	sub {	326	sub {
242	$guard if 0; # keep guard alive, but don't cause runtime overhead	327	$guard if 0; # keep guard alive, but don't cause runtime overhead
243		328
244	_log $pkg, $level, @_	329	_log $ctx, $level, @_
245	if $$renabled;	330	if $$renabled;
246	}	331	}
247	}	332	}
248		333
249	#TODO	334	sub logger($;$) {
		335	_logger
		336	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		337	@_
		338	}
250		339
251	=back	340	=back
252		341
253	=head1 CONFIGURATION FUNCTIONALITY	342	=head1 LOGGING CONTEXTS
254		343
255	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	344	This module associates every log message with a so-called I<logging
256	#TODO	345	context>, based on the package of the caller. Every perl package has its
		346	own logging context.
		347
		348	A logging context has three major responsibilities: filtering, logging and
		349	propagating the message.
		350
		351	For the first purpose, filtering, each context has a set of logging
		352	levels, called the log level mask. Messages not in the set will be ignored
		353	by this context (masked).
		354
		355	For logging, the context stores a formatting callback (which takes the
		356	timestamp, context, level and string message and formats it in the way
		357	it should be logged) and a logging callback (which is responsible for
		358	actually logging the formatted message and telling C<AnyEvent::Log>
		359	whether it has consumed the message, or whether it should be propagated).
		360
		361	For propagation, a context can have any number of attached I<parent
		362	contexts>. Any message that is neither masked by the logging mask nor
		363	masked by the logging callback returning true will be passed to all parent
		364	contexts.
		365
		366	Each call to a logging function will log the message at most once per
		367	context, so it does not matter (much) if there are cycles or if the
		368	message can arrive at the same context via multiple paths.
		369
		370	=head2 DEFAULTS
		371
		372	By default, all logging contexts have an full set of log levels ("all"), a
		373	disabled logging callback and the default formatting callback.
		374
		375	Package contexts have the package name as logging title by default.
		376
		377	They have exactly one parent - the context of the "parent" package. The
		378	parent package is simply defined to be the package name without the last
		379	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		380	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the
		381	exception of the rule - just like the parent of any package name in
		382	Perl is C<main>, the default parent of any toplevel package context is
		383	C<AnyEvent::Log::Top>.
		384
		385	Since perl packages form only an approximate hierarchy, this parent
		386	context can of course be removed.
		387
		388	All other (anonymous) contexts have no parents and an empty title by
		389	default.
		390
		391	When the module is loaded it creates the default context called
		392	C<AnyEvent::Log::Default>, which simply logs everything to STDERR and
		393	doesn't propagate anything anywhere by default. The purpose of the default
		394	context is to provide a convenient place to override the global logging
		395	target or to attach additional log targets. It's not meant for filtering.
		396
		397	It then creates the root context called C<AnyEvent::Log::Root> and
		398	sets its log level set to all levels up to the one specified by
		399	C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the default logging
		400	context to it. The purpose of the root context is to simply provide
		401	filtering according to some global log level.
		402
		403	Finally it creates the toplevel package context called
		404	C<AnyEvent::Log::Top> and attached the root context but otherwise leaves
		405	it at default config. It's purpose is simply to collect all log messages
		406	system-wide.
		407
		408	These three special contexts can also be referred to by the names
		409	C<AE::Log::Default>, C<AE::Log::Root> and C<AE::Log::Top>.
		410
		411	The effect of all this is that log messages, by default, wander up
		412	to the root context where log messages with lower priority then
		413	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the
		414	AnyEvent::Log::Default context to be logged to STDERR.
		415
		416	Splitting the top level context into three contexts makes it easy to set
		417	a global logging level (by modifying the root context), but still allow
		418	other contexts to log, for example, their debug and trace messages to the
		419	default target despite the global logging level, or to attach additional
		420	log targets that log messages, regardless of the global logging level.
		421
		422	It also makes it easy to replace the default STDERR-logger by something
		423	that logs to a file, or to attach additional logging targets.
		424
		425	=head2 CREATING/FINDING/DESTROYING CONTEXTS
257		426
258	=over 4	427	=over 4
259		428
260	=item $ctx = AnyEvent::Log::cfg [$pkg]	429	=item $ctx = AnyEvent::Log::ctx [$pkg]
261		430
262	Returns a I<config> object for the given package name (or previously	431	This function creates or returns a logging context (which is an object).
263	created package-less configuration). If no package name, or C<undef>, is	432
		433	If a package name is given, then the context for that packlage is
		434	returned. If it is called without any arguments, then the context for the
		435	callers package is returned (i.e. the same context as a C<AE::log> call
		436	would use).
		437
264	given, then it creates a new anonymous context that is not tied to any	438	If C<undef> is given, then it creates a new anonymous context that is not
265	package.	439	tied to any package and is destroyed when no longer referenced.
266		440
267	=cut	441	=cut
268		442
269	sub cfg(;$) {	443	sub ctx(;$) {
270	my $name = shift;	444	my $pkg = @_ ? shift : (caller)[0];
271		445
272	my $ctx = defined $name ? $CTX{$name} : undef;	446	ref $pkg
		447	? $pkg
		448	: defined $pkg
		449	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
		450	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
		451	}
273		452
274	unless ($ctx) {	453	=item AnyEvent::Log::reset
275	$ctx = bless {}, "AnyEvent::Log::Ctx";	454
276	$name = -$ctx unless defined $name;	455	Deletes all contexts and recreates the default hierarchy, i.e. resets the
277	$ctx->{name} = $name;	456	logging subsystem to defaults.
278	$CTX{$name} = $ctx;	457
		458	This can be used to implement config-file (re-)loading: before loading a
		459	configuration, reset all contexts.
		460
		461	=cut
		462
		463	sub reset {
		464	@$_ = () for values %CTX; # just to be sure - to kill circular logging dependencies
		465	%CTX = ();
		466
		467	my $default = ctx undef;
		468	$default->title ("AnyEvent::Log::Default");
		469	$default->log_cb (sub {
		470	print STDERR shift;
		471	0
279	}	472	});
		473	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $default;
280		474
281	$ctx	475	my $root = ctx undef;
		476	$root->title ("AnyEvent::Log::Root");
		477	$root->level ($AnyEvent::VERBOSE);
		478	$root->attach ($default);
		479	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $root;
		480
		481	my $top = ctx undef;
		482	$top->title ("AnyEvent::Log::Top");
		483	$top->attach ($root);
		484	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $top;
282	}	485	}
		486
		487	AnyEvent::Log::reset;
		488
		489	package AnyEvent::Log::Default;
		490	package AE::Log::Default;
		491	package AnyEvent::Log::Root;
		492	package AE::Log::Root;
		493	package AnyEvent::Log::Top;
		494	package AE::Log::Top;
		495
		496	=back
		497
		498	=cut
283		499
284	package AnyEvent::Log::Ctx;	500	package AnyEvent::Log::Ctx;
285		501
286	sub DESTROY {	502	# 0 1 2 3 4
287	# if only one member is remaining (name!) then delete this context	503	# [$title, $level, %$parents, &$logcb, &$fmtcb]
288	delete $CTX{$_[0]{name}}	504
289	if 1 == scalar keys %{ $_[0] };	505	=head2 CONFIGURING A LOG CONTEXT
		506
		507	The following methods can be used to configure the logging context.
		508
		509	=over 4
		510
		511	=item $ctx->title ([$new_title])
		512
		513	Returns the title of the logging context - this is the package name, for
		514	package contexts, and a user defined string for all others.
		515
		516	If C<$new_title> is given, then it replaces the package name or title.
		517
		518	=cut
		519
		520	sub title {
		521	$_[0][0] = $_[1] if @_ > 1;
		522	$_[0][0]
290	}	523	}
		524
		525	=back
		526
		527	=head3 LOGGING LEVELS
		528
		529	The following methods deal with the logging level set associated with the
		530	log context.
		531
		532	The most common method to use is probably C<< $ctx->level ($level) >>,
		533	which configures the specified and any higher priority levels.
		534
		535	All functions which accept a list of levels also accept the special string
		536	C<all> which expands to all logging levels.
		537
		538	=over 4
		539
		540	=item $ctx->levels ($level[, $level...)
		541
		542	Enables logging for the given levels and disables it for all others.
		543
		544	=item $ctx->level ($level)
		545
		546	Enables logging for the given level and all lower level (higher priority)
		547	ones. In addition to normal logging levels, specifying a level of C<0> or
		548	C<off> disables all logging for this level.
		549
		550	Example: log warnings, errors and higher priority messages.
		551
		552	$ctx->level ("warn");
		553	$ctx->level (5); # same thing, just numeric
		554
		555	=item $ctx->enable ($level[, $level...])
		556
		557	Enables logging for the given levels, leaving all others unchanged.
		558
		559	=item $ctx->disable ($level[, $level...])
		560
		561	Disables logging for the given levels, leaving all others unchanged.
		562
		563	=cut
		564
		565	sub _lvl_lst {
		566	map {
		567	$_ > 0 && $_ <= 9 ? $_+0
		568	: $_ eq "all" ? (1 .. 9)
		569	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
		570	} @_
		571	}
		572
		573	our $NOP_CB = sub { 0 };
		574
		575	sub levels {
		576	my $ctx = shift;
		577	$ctx->[1] = 0;
		578	$ctx->[1] \|= 1 << $_
		579	for &_lvl_lst;
		580	AnyEvent::Log::_reassess;
		581	}
		582
		583	sub level {
		584	my $ctx = shift;
		585	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		586
		587	$ctx->[1] = ((1 << $lvl) - 1) << 1;
		588	AnyEvent::Log::_reassess;
		589	}
		590
		591	sub enable {
		592	my $ctx = shift;
		593	$ctx->[1] \|= 1 << $_
		594	for &_lvl_lst;
		595	AnyEvent::Log::_reassess;
		596	}
		597
		598	sub disable {
		599	my $ctx = shift;
		600	$ctx->[1] &= ~(1 << $_)
		601	for &_lvl_lst;
		602	AnyEvent::Log::_reassess;
		603	}
		604
		605	=back
		606
		607	=head3 PARENT CONTEXTS
		608
		609	The following methods attach and detach another logging context to a
		610	logging context.
		611
		612	Log messages are propagated to all parent contexts, unless the logging
		613	callback consumes the message.
		614
		615	=over 4
		616
		617	=item $ctx->attach ($ctx2[, $ctx3...])
		618
		619	Attaches the given contexts as parents to this context. It is not an error
		620	to add a context twice (the second add will be ignored).
		621
		622	A context can be specified either as package name or as a context object.
		623
		624	=item $ctx->detach ($ctx2[, $ctx3...])
		625
		626	Removes the given parents from this context - it's not an error to attempt
		627	to remove a context that hasn't been added.
		628
		629	A context can be specified either as package name or as a context object.
		630
		631	=item $ctx->parents ($ctx2[, $ctx3...])
		632
		633	Replaces all parents attached to this context by the ones given.
		634
		635	=cut
		636
		637	sub attach {
		638	my $ctx = shift;
		639
		640	$ctx->[2]{$_+0} = $_
		641	for map { AnyEvent::Log::ctx $_ } @_;
		642	}
		643
		644	sub detach {
		645	my $ctx = shift;
		646
		647	delete $ctx->[2]{$_+0}
		648	for map { AnyEvent::Log::ctx $_ } @_;
		649	}
		650
		651	sub parents {
		652	undef $_[0][2];
		653	&attach;
		654	}
		655
		656	=back
		657
		658	=head3 MESSAGE LOGGING
		659
		660	The following methods configure how the logging context actually does
		661	the logging (which consists of formatting the message and printing it or
		662	whatever it wants to do with it) and also allows you to log messages
		663	directly to a context, without going via your package context.
		664
		665	=over 4
		666
		667	=item $ctx->log_cb ($cb->($str))
		668
		669	Replaces the logging callback on the context (C<undef> disables the
		670	logging callback).
		671
		672	The logging callback is responsible for handling formatted log messages
		673	(see C<fmt_cb> below) - normally simple text strings that end with a
		674	newline (and are possibly multiline themselves).
		675
		676	It also has to return true iff it has consumed the log message, and false
		677	if it hasn't. Consuming a message means that it will not be sent to any
		678	parent context. When in doubt, return C<0> from your logging callback.
		679
		680	Example: a very simple logging callback, simply dump the message to STDOUT
		681	and do not consume it.
		682
		683	$ctx->log_cb (sub { print STDERR shift; 0 });
		684
		685	You can filter messages by having a log callback that simply returns C<1>
		686	and does not do anything with the message, but this counts as "message
		687	being logged" and might not be very efficient.
		688
		689	Example: propagate all messages except for log levels "debug" and
		690	"trace". The messages will still be generated, though, which can slow down
		691	your program.
		692
		693	$ctx->levels ("debug", "trace");
		694	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		695
		696	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))
		697
		698	Replaces the formatting callback on the context (C<undef> restores the
		699	default formatter).
		700
		701	The callback is passed the (possibly fractional) timestamp, the original
		702	logging context, the (numeric) logging level and the raw message string and needs to
		703	return a formatted log message. In most cases this will be a string, but
		704	it could just as well be an array reference that just stores the values.
		705
		706	Example: format just the raw message, with numeric log level in angle
		707	brackets.
		708
		709	$ctx->fmt_cb (sub {
		710	my ($time, $ctx, $lvl, $msg) = @_;
		711
		712	"<$lvl>$msg\n"
		713	});
		714
		715	Example: return an array reference with just the log values, and use
		716	C<PApp::SQL::sql_exec> to store the emssage in a database.
		717
		718	$ctx->fmt_cb (sub { \@_ });
		719	$ctx->log_cb (sub {
		720	my ($msg) = @_;
		721
		722	sql_exec "insert into log (when, subsys, prio, msg) values (?, ?, ?, ?)",
		723	$msg->[0] + 0,
		724	"$msg->[1]",
		725	$msg->[2] + 0,
		726	"$msg->[3]";
		727
		728	0
		729	});
		730
		731	=cut
		732
		733	sub log_cb {
		734	my ($ctx, $cb) = @_;
		735
		736	$ctx->[3] = $cb;
		737	}
		738
		739	sub fmt_cb {
		740	my ($ctx, $cb) = @_;
		741
		742	$ctx->[4] = $cb;
		743	}
		744
		745	=item $ctx->log ($level, $msg[, @params])
		746
		747	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		748
		749	=item $logger = $ctx->logger ($level[, \$enabled])
		750
		751	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		752	context.
		753
		754	=cut
		755
		756	*log = \&AnyEvent::Log::_log;
		757	*logger = \&AnyEvent::Log::_logger;
291		758
292	1;	759	1;
293		760
294	=back	761	=back
295		762

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.7 by root, Thu Aug 18 18:02:11 2011 UTC vs. Revision 1.11 by root, Sat Aug 20 01:03:09 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.7 by root, Thu Aug 18 18:02:11 2011 UTC vs.
Revision 1.11 by root, Sat Aug 20 01:03:09 2011 UTC