[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 1.12 by root, Sat Aug 20 01:33:10 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 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);
25		40
26	=head1 DESCRIPTION	41	=head1 DESCRIPTION
27		42
28	This module implements a relatively simple "logging framework". It doesn't	43	This module implements a relatively simple "logging framework". It doesn't
29	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
30	AnyEvent - AnyEvent simply creates logging messages internally, and this	45	AnyEvent - AnyEvent simply creates logging messages internally, and this
31	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
32	using it from other modules as well.	47	using it from other modules as well.
33		48
34	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
35	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
36	before starting your program.#TODO	51	starting your program, or change the logging level at runtime with
		52	something like:
37		53
38	Possible future extensions are to allow custom log targets (where the	54	use AnyEvent;
39	level is an object), log filtering based on package, formatting, aliasing	55	(AnyEvent::Log::ctx "")->level ("info");
40	or package groups.
41		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
42	=head1 LOG FUNCTIONS	62	=head1 LOGGING FUNCTIONS
43		63
44	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
45	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
46	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
47	loaded.	67	loaded.
…		…
71	"$now_str1$f$now_str2"	91	"$now_str1$f$now_str2"
72	}	92	}
73		93
74	our %CTX; # all logging contexts	94	our %CTX; # all logging contexts
75		95
76	my $default_log_cb = sub { 0 };
77
78	# creates a default package context object for the given package	96	# creates a default package context object for the given package
79	sub _pkg_ctx($) {	97	sub _pkg_ctx($) {
80	my $ctx = bless [$_[0], 0, {}, $default_log_cb], "AnyEvent::Log::Ctx";	98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
81		99
82	# link "parent" package	100	# link "parent" package
83	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "";	101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";
84		102
85	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);	103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
86	$ctx->[2]{$pkg+0} = $pkg;	104	$ctx->[2]{$pkg+0} = $pkg;
87		105
88	$ctx	106	$ctx
…		…
114	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
115	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	133	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	134	need any additional functionality), as those functions will load the
117	logging module on demand only. They are also much shorter to write.	135	logging module on demand only. They are also much shorter to write.
118		136
119	Also, if you otpionally generate a lot of debug messages (such as when	137	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	138	tracing some code), you should look into using a logger callback and a
121	boolean enabler (see C<logger>, below).	139	boolean enabler (see C<logger>, below).
122		140
123	Example: log something at error level.	141	Example: log something at error level.
124		142
…		…
146	debug => 8,	164	debug => 8,
147	trace => 9,	165	trace => 9,
148	);	166	);
149		167
150	sub now () { time }	168	sub now () { time }
		169
151	AnyEvent::post_detect {	170	AnyEvent::post_detect {
152	*now = \&AE::now;	171	*now = \&AE::now;
153	};	172	};
154		173
155	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);
156		175
157	# time, ctx, level, msg	176	# time, ctx, level, msg
158	sub _format($$$$) {	177	sub _format($$$$) {
159	my $pfx = ft $_[0];	178	my $ts = ft $_[0];
		179	my $ct = " ";
160		180
161	join "",	181	my @res;
162	map "$pfx $_\n",	182
163	split /\n/,
164	sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]	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
165	}	189	}
166		190
167	sub _log {	191	sub _log {
168	my ($ctx, $level, $format, @args) = @_;	192	my ($ctx, $level, $format, @args) = @_;
169		193
		194	$level = $level > 0 && $level <= 9
		195	? $level+0
170	$level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	196	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
171		197
172	my $mask = 1 << $level;	198	my $mask = 1 << $level;
173	my $now = AE::now;
174		199
175	my (@ctx, $did_format, $fmt);	200	my (%seen, @ctx, $now, $fmt);
176		201
177	do {	202	do
178	if ($ctx->[1] & $mask) {	203	{
		204	# skip if masked
		205	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		206	if ($ctx->[3]) {
179	# logging target found	207	# logging target found
180		208
181	# get raw message	209	# now get raw message, unless we have it already
182	unless ($did_format) {	210	unless ($now) {
183	$format = $format->() if ref $format;	211	$format = $format->() if ref $format;
184	$format = sprintf $format, @args if @args;	212	$format = sprintf $format, @args if @args;
185	$format =~ s/\n$//;	213	$format =~ s/\n$//;
186	$did_format = 1;	214	$now = AE::now;
187	};	215	};
188		216
189	# format msg	217	# format msg
190	my $str = $ctx->[4]	218	my $str = $ctx->[4]
191	? $ctx->[4]($now, $_[0], $level, $format)	219	? $ctx->[4]($now, $_[0], $level, $format)
192	: $fmt \|\|= _format $now, $_[0], $level, $format;	220	: $fmt \|\|= _format $now, $_[0], $level, $format;
193		221
194	$ctx->[3]($str)	222	$ctx->[3]($str);
195	and next;	223	}
		224
		225	# not masked, not consumed - propagate to parent contexts
		226	push @ctx, values %{ $ctx->[2] };
		227	}
196	}	228	}
197
198	# not consume - push parent contexts
199	push @ctx, values %{ $ctx->[2] };
200	} while $ctx = pop @ctx;	229	while $ctx = pop @ctx;
201		230
202	exit 1 if $level <= 1;	231	exit 1 if $level <= 1;
203	}	232	}
204		233
205	sub log($$;@) {	234	sub log($$;@) {
…		…
258	# re-assess logging status for all loggers	287	# re-assess logging status for all loggers
259	sub _reassess {	288	sub _reassess {
260	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	289	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
261	my ($ctx, $level, $renabled) = @$_;	290	my ($ctx, $level, $renabled) = @$_;
262		291
263	# to detetc whether a message would be logged, we # actually	292	# to detect whether a message would be logged, we # actually
264	# try to log one and die. this isn't # fast, but we can be	293	# try to log one and die. this isn't fast, but we can be
265	# sure that the logging decision is correct :)	294	# sure that the logging decision is correct :)
266		295
267	$$renabled = !eval {	296	$$renabled = !eval {
268	local $SIG{__DIE__};	297	local $SIG{__DIE__};
269		298
…		…
306	_logger	335	_logger
307	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	336	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
308	@_	337	@_
309	}	338	}
310		339
311	#TODO
312
313	=back	340	=back
314		341
315	=head1 CONFIGURATION FUNCTIONALITY	342	=head1 LOGGING CONTEXTS
316		343
317	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
		345	context>, based on the package of the caller. Every perl package has its
		346	own logging context.
318		347
319	#TODO: wahst a context	348	A logging context has three major responsibilities: filtering, logging and
320	#TODO	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 top-level 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> (also stored in C<$AnyEvent::Log::Default>),
		393	which simply logs everything to STDERR and doesn't propagate anything
		394	anywhere by default. The purpose of the default context is to provide
		395	a convenient place to override the global logging target or to attach
		396	additional log targets. It's not meant for filtering.
		397
		398	It then creates the root context called C<AnyEvent::Log::Root> (also
		399	stored in C<$AnyEvent::Log::Root>) and sets its log level set to all
		400	levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It
		401	then attached the default logging context to it. The purpose of the root
		402	context is to simply provide filtering according to some global log level.
		403
		404	Finally it creates the top-level package context called
		405	C<AnyEvent::Log::Top> (also stored in, you might have guessed,
		406	C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
		407	it at default config. It's purpose is simply to collect all log messages
		408	system-wide.
		409
		410	These three special contexts can also be referred to by the
		411	package/context names C<AE::Log::Default>, C<AE::Log::Root> and
		412	C<AE::Log::Top>.
		413
		414	The effect of all this is that log messages, by default, wander up
		415	to the root context where log messages with lower priority then
		416	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the
		417	AnyEvent::Log::Default context to be logged to STDERR.
		418
		419	Splitting the top level context into three contexts makes it easy to set
		420	a global logging level (by modifying the root context), but still allow
		421	other contexts to log, for example, their debug and trace messages to the
		422	default target despite the global logging level, or to attach additional
		423	log targets that log messages, regardless of the global logging level.
		424
		425	It also makes it easy to replace the default STDERR-logger by something
		426	that logs to a file, or to attach additional logging targets.
		427
		428	=head2 CREATING/FINDING/DESTROYING CONTEXTS
321		429
322	=over 4	430	=over 4
323		431
324	=item $ctx = AnyEvent::Log::ctx [$pkg]	432	=item $ctx = AnyEvent::Log::ctx [$pkg]
325		433
326	Returns a I<config> object for the given package name.	434	This function creates or returns a logging context (which is an object).
327		435
328	If no package name is given, returns the context for the current perl	436	If a package name is given, then the context for that packlage is
		437	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).	438	callers package is returned (i.e. the same context as a C<AE::log> call
		439	would use).
330		440
331	If C<undef> is given, then it creates a new anonymous context that is not	441	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.	442	tied to any package and is destroyed when no longer referenced.
333		443
334	=cut	444	=cut
…		…
338		448
339	ref $pkg	449	ref $pkg
340	? $pkg	450	? $pkg
341	: defined $pkg	451	: defined $pkg
342	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg	452	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
343	: bless [undef, 0, undef, $default_log_cb], "AnyEvent::Log::Ctx"	453	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
344	}	454	}
345		455
346	# create default root context	456	=item AnyEvent::Log::reset
347	{	457
		458	Deletes all contexts and recreates the default hierarchy, i.e. resets the
		459	logging subsystem to defaults.
		460
		461	This can be used to implement config-file (re-)loading: before loading a
		462	configuration, reset all contexts.
		463
		464	=cut
		465
		466	sub reset {
		467	@$_ = () for values %CTX; # just to be sure - to kill circular logging dependencies
		468	%CTX = ();
		469
348	my $root = ctx undef;	470	my $default = ctx undef;
349	$root->[0] = "";	471	$default->title ("AnyEvent::Log::Default");
350	$root->title ("default");
351	$root->level ($AnyEvent::VERBOSE);
352	$root->log_cb (sub {	472	$default->log_cb (sub {
353	print STDERR shift;	473	print STDERR shift;
354	0	474	0
355	});	475	});
356	$CTX{""} = $root;	476	$AnyEvent::Log::Default = $CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $default;
		477
		478	my $root = ctx undef;
		479	$root->title ("AnyEvent::Log::Root");
		480	$root->level ($AnyEvent::VERBOSE);
		481	$root->attach ($default);
		482	$AnyEvent::Log::Root = $CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $root;
		483
		484	my $top = ctx undef;
		485	$top->title ("AnyEvent::Log::Top");
		486	$top->attach ($root);
		487	$AnyEvent::Log::Top = $CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $top;
357	}	488	}
		489
		490	AnyEvent::Log::reset;
		491
		492	# hello, CPAN, please catch me
		493	package AnyEvent::Log::Default;
		494	package AE::Log::Default;
		495	package AnyEvent::Log::Root;
		496	package AE::Log::Root;
		497	package AnyEvent::Log::Top;
		498	package AE::Log::Top;
358		499
359	package AnyEvent::Log::Ctx;	500	package AnyEvent::Log::Ctx;
360		501
361	# 0 1 2 3 4	502	# 0 1 2 3 4
362	# [$title, $level, %$parents, &$logcb, &$fmtcb]	503	# [$title, $level, %$parents, &$logcb, &$fmtcb]
		504
		505	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		506
		507	This is a convenience constructor that makes it simpler to construct
		508	anonymous logging contexts.
		509
		510	Each key-value pair results in an invocation of the method of the same
		511	name as the key with the value as parameter, unless the value is an
		512	arrayref, in which case it calls the method with the contents of the
		513	array. The methods are called in the same order as specified.
		514
		515	Example: create a new logging context and set both the default logging
		516	level, some parent contexts and a logging callback.
		517
		518	$ctx = new AnyEvent::Log::Ctx
		519	title => "dubious messages",
		520	level => "error",
		521	log_cb => sub { print STDOUT shift; 0 },
		522	parents => [$ctx1, $ctx, $ctx2],
		523	;
		524
		525	=back
		526
		527	=cut
		528
		529	sub new {
		530	my $class = shift;
		531
		532	my $ctx = AnyEvent::Log::ctx undef;
		533
		534	while (@_) {
		535	my ($k, $v) = splice @_, 0, 2;
		536	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		537	}
		538
		539	bless $ctx, $class # do we really support subclassing, hmm?
		540	}
		541
		542
		543	=head2 CONFIGURING A LOG CONTEXT
		544
		545	The following methods can be used to configure the logging context.
		546
		547	=over 4
363		548
364	=item $ctx->title ([$new_title])	549	=item $ctx->title ([$new_title])
365		550
366	Returns the title of the logging context - this is the package name, for	551	Returns the title of the logging context - this is the package name, for
367	package contexts, and a user defined string for all others.	552	package contexts, and a user defined string for all others.
…		…
373	sub title {	558	sub title {
374	$_[0][0] = $_[1] if @_ > 1;	559	$_[0][0] = $_[1] if @_ > 1;
375	$_[0][0]	560	$_[0][0]
376	}	561	}
377		562
		563	=back
		564
		565	=head3 LOGGING LEVELS
		566
		567	The following methods deal with the logging level set associated with the
		568	log context.
		569
		570	The most common method to use is probably C<< $ctx->level ($level) >>,
		571	which configures the specified and any higher priority levels.
		572
		573	All functions which accept a list of levels also accept the special string
		574	C<all> which expands to all logging levels.
		575
		576	=over 4
		577
378	=item $ctx->levels ($level[, $level...)	578	=item $ctx->levels ($level[, $level...)
379		579
380	Enables logging fot the given levels and disables it for all others.	580	Enables logging for the given levels and disables it for all others.
381		581
382	=item $ctx->level ($level)	582	=item $ctx->level ($level)
383		583
384	Enables logging for the given level and all lower level (higher priority)	584	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	585	ones. In addition to normal logging levels, specifying a level of C<0> or
386	level.	586	C<off> disables all logging for this level.
387		587
388	Example: log warnings, errors and higher priority messages.	588	Example: log warnings, errors and higher priority messages.
389		589
390	$ctx->level ("warn");	590	$ctx->level ("warn");
391	$ctx->level (5); # same thing, just numeric	591	$ctx->level (5); # same thing, just numeric
…		…
399	Disables logging for the given levels, leaving all others unchanged.	599	Disables logging for the given levels, leaving all others unchanged.
400		600
401	=cut	601	=cut
402		602
403	sub _lvl_lst {	603	sub _lvl_lst {
		604	map {
		605	$_ > 0 && $_ <= 9 ? $_+0
		606	: $_ eq "all" ? (1 .. 9)
404	map { $_ > 0 && $_ <= 9 ? $_+0 : $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught" }	607	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
405	@_	608	} @_
406	}	609	}
407		610
408	our $NOP_CB = sub { 0 };	611	our $NOP_CB = sub { 0 };
409		612
410	sub levels {	613	sub levels {
…		…
415	AnyEvent::Log::_reassess;	618	AnyEvent::Log::_reassess;
416	}	619	}
417		620
418	sub level {	621	sub level {
419	my $ctx = shift;	622	my $ctx = shift;
420	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[0];	623	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		624
421	$ctx->[1] = ((1 << $lvl) - 1) << 1;	625	$ctx->[1] = ((1 << $lvl) - 1) << 1;
422	AnyEvent::Log::_reassess;	626	AnyEvent::Log::_reassess;
423	}	627	}
424		628
425	sub enable {	629	sub enable {
…		…
434	$ctx->[1] &= ~(1 << $_)	638	$ctx->[1] &= ~(1 << $_)
435	for &_lvl_lst;	639	for &_lvl_lst;
436	AnyEvent::Log::_reassess;	640	AnyEvent::Log::_reassess;
437	}	641	}
438		642
		643	=back
		644
		645	=head3 PARENT CONTEXTS
		646
		647	The following methods attach and detach another logging context to a
		648	logging context.
		649
		650	Log messages are propagated to all parent contexts, unless the logging
		651	callback consumes the message.
		652
		653	=over 4
		654
439	=item $ctx->attach ($ctx2[, $ctx3...])	655	=item $ctx->attach ($ctx2[, $ctx3...])
440		656
441	Attaches the given contexts as parents to this context. It is not an error	657	Attaches the given contexts as parents to this context. It is not an error
442	to add a context twice (the second add will be ignored).	658	to add a context twice (the second add will be ignored).
443		659
…		…
448	Removes the given parents from this context - it's not an error to attempt	664	Removes the given parents from this context - it's not an error to attempt
449	to remove a context that hasn't been added.	665	to remove a context that hasn't been added.
450		666
451	A context can be specified either as package name or as a context object.	667	A context can be specified either as package name or as a context object.
452		668
		669	=item $ctx->parents ($ctx2[, $ctx3...])
		670
		671	Replaces all parents attached to this context by the ones given.
		672
453	=cut	673	=cut
454		674
455	sub attach {	675	sub attach {
456	my $ctx = shift;	676	my $ctx = shift;
457		677
…		…
463	my $ctx = shift;	683	my $ctx = shift;
464		684
465	delete $ctx->[2]{$_+0}	685	delete $ctx->[2]{$_+0}
466	for map { AnyEvent::Log::ctx $_ } @_;	686	for map { AnyEvent::Log::ctx $_ } @_;
467	}	687	}
		688
		689	sub parents {
		690	undef $_[0][2];
		691	&attach;
		692	}
		693
		694	=back
		695
		696	=head3 MESSAGE LOGGING
		697
		698	The following methods configure how the logging context actually does
		699	the logging (which consists of formatting the message and printing it or
		700	whatever it wants to do with it) and also allows you to log messages
		701	directly to a context, without going via your package context.
		702
		703	=over 4
468		704
469	=item $ctx->log_cb ($cb->($str))	705	=item $ctx->log_cb ($cb->($str))
470		706
471	Replaces the logging callback on the context (C<undef> disables the	707	Replaces the logging callback on the context (C<undef> disables the
472	logging callback).	708	logging callback).
…		…
482	Example: a very simple logging callback, simply dump the message to STDOUT	718	Example: a very simple logging callback, simply dump the message to STDOUT
483	and do not consume it.	719	and do not consume it.
484		720
485	$ctx->log_cb (sub { print STDERR shift; 0 });	721	$ctx->log_cb (sub { print STDERR shift; 0 });
486		722
		723	You can filter messages by having a log callback that simply returns C<1>
		724	and does not do anything with the message, but this counts as "message
		725	being logged" and might not be very efficient.
		726
		727	Example: propagate all messages except for log levels "debug" and
		728	"trace". The messages will still be generated, though, which can slow down
		729	your program.
		730
		731	$ctx->levels ("debug", "trace");
		732	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		733
487	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	734	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))
488		735
489	Replaces the fornatting callback on the cobntext (C<undef> restores the	736	Replaces the formatting callback on the context (C<undef> restores the
490	default formatter).	737	default formatter).
491		738
492	The callback is passed the (possibly fractional) timestamp, the original	739	The callback is passed the (possibly fractional) timestamp, the original
493	logging context, the (numeric) logging level and the raw message string and needs to	740	logging context, the (numeric) logging level and the raw message string and needs to
494	return a formatted log message. In most cases this will be a string, but	741	return a formatted log message. In most cases this will be a string, but
…		…
522	=cut	769	=cut
523		770
524	sub log_cb {	771	sub log_cb {
525	my ($ctx, $cb) = @_;	772	my ($ctx, $cb) = @_;
526		773
527	$ctx->[3] = $cb \|\| $default_log_cb;	774	$ctx->[3] = $cb;
528	}	775	}
529		776
530	sub fmt_cb {	777	sub fmt_cb {
531	my ($ctx, $cb) = @_;	778	my ($ctx, $cb) = @_;
532		779
…		…
549		796
550	1;	797	1;
551		798
552	=back	799	=back
553		800
		801	=head1 EXAMPLES
		802
		803	This section shows some common configurations.
		804
		805	=over 4
		806
		807	=item Setting the global logging level.
		808
		809	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		810	running your program, or modify the log level of the root context:
		811
		812	PERL_ANYEVENT_VERBOSE=5 ./myprog
		813
		814	$AnyEvent::Log::Root->level ("warn");
		815
		816	=item Append all messages to a file instead of sending them to STDERR.
		817
		818	This is affected by the global logging level.
		819
		820	open my $fh, ">>", $path
		821	or die "$path: $!";
		822
		823	$AnyEvent::Log::Default->log_cb (sub {
		824	syswrite $fh, shift;
		825	0
		826	});
		827
		828	=item Write all messages with priority C<error> and higher to a file.
		829
		830	This writes them only when the global logging level allows it, because
		831	it is attached to the default context which is invoked I<after> global
		832	filtering.
		833
		834	open my $fh, ">>", $path
		835	or die "$path: $!";
		836
		837	$AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx
		838	log_cb => sub { syswrite $fh, shift; 0 });
		839
		840	This writes them regardless of the global logging level, because it is
		841	attached to the toplevel context, which receives all messages I<before>
		842	the global filtering.
		843
		844	$AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx
		845	log_cb => sub { syswrite $fh, shift; 0 });
		846
		847	In both cases, messages are still written to STDOUT.
		848
		849	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		850
		851	Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug>
		852	context and increase the C<AnyEvent::Debug> logging level - this simply
		853	circumvents the global filtering for trace messages.
		854
		855	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		856	$debug->attach ($AnyEvent::Log::Default);
		857	$debug->levels ("trace"); # not "level"!
		858
		859	=back
		860
554	=head1 AUTHOR	861	=head1 AUTHOR
555		862
556	Marc Lehmann <schmorp@schmorp.de>	863	Marc Lehmann <schmorp@schmorp.de>
557	http://home.schmorp.de/	864	http://home.schmorp.de/
558		865

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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 1.12 by root, Sat Aug 20 01:33:10 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
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Revision 1.12 by root, Sat Aug 20 01:33:10 2011 UTC