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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.11 by root, Sat Aug 20 01:03:09 2011 UTC vs.
Revision 1.20 by root, Sat Aug 20 22:27:07 2011 UTC

…		…
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	# configuration	23	# configuration
24		24
25	# set logging for this package to maximum	25	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("all");	26	AnyEvent::Log::ctx->level ("error");
27		27
28	# set logging globally to anything below debug	28	# set logging globally to anything below debug
29	(AnyEvent::Log::ctx "")->level ("notice");	29	$AnyEvent::Log::FILTER->level ("notice");
30		30
31	# see also EXAMPLES, below	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);
40		32
41	=head1 DESCRIPTION	33	=head1 DESCRIPTION
42		34
43	This module implements a relatively simple "logging framework". It doesn't	35	This module implements a relatively simple "logging framework". It doesn't
44	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
45	AnyEvent - AnyEvent simply creates logging messages internally, and this	37	AnyEvent - AnyEvent simply creates logging messages internally, and this
46	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
47	using it from other modules as well.	39	using it from other modules as well.
48		40
49	Remember that the default verbosity level is C<0>, so nothing will be	41	Remember that the default verbosity level is C<0> (C<off>), so nothing
50	logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before	42	will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
51	starting your program, or change the logging level at runtime with	43	before starting your program, or change the logging level at runtime with
52	something like:	44	something like:
53		45
54	use AnyEvent;	46	use AnyEvent::Log;
55	(AnyEvent::Log::ctx "")->level ("info");	47	AnyEvent::Log::FILTER->level ("info");
56		48
57	The design goal behind this module was to keep it simple (and small),	49	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	50	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	51	extensive enough for the most common tasks, such as logging to multiple
60	targets, or being able to log into a database.	52	targets, or being able to log into a database.
61		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
62	=head1 LOGGING FUNCTIONS	89	=head1 LOGGING FUNCTIONS
63		90
64	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
65	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
66	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
67	loaded.	94	loaded.
68		95
69	=over 4	96	=over 4
70		97
…		…
75	use Carp ();	102	use Carp ();
76	use POSIX ();	103	use POSIX ();
77		104
78	use AnyEvent (); BEGIN { AnyEvent::common_sense }	105	use AnyEvent (); BEGIN { AnyEvent::common_sense }
79	use AnyEvent::Util ();	106	use AnyEvent::Util ();
		107
		108	our $VERSION = $AnyEvent::VERSION;
		109
		110	our ($COLLECT, $FILTER, $LOG);
80		111
81	our ($now_int, $now_str1, $now_str2);	112	our ($now_int, $now_str1, $now_str2);
82		113
83	# Format Time, not public - yet?	114	# Format Time, not public - yet?
84	sub ft($) {	115	sub ft($) {
…		…
89	if $now_int != $i;	120	if $now_int != $i;
90		121
91	"$now_str1$f$now_str2"	122	"$now_str1$f$now_str2"
92	}	123	}
93		124
94	our %CTX; # all logging contexts	125	our %CTX; # all package contexts
95		126
96	# creates a default package context object for the given package	127	# creates a default package context object for the given package
97	sub _pkg_ctx($) {	128	sub _pkg_ctx($) {
98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	129	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
99		130
100	# link "parent" package	131	# link "parent" package
101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";	132	my $parent = $_[0] =~ /^(.+)::/
		133	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		134	: $COLLECT;
102		135
103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
104	$ctx->[2]{$pkg+0} = $pkg;	136	$ctx->[2]{$parent+0} = $parent;
105		137
106	$ctx	138	$ctx
107	}	139	}
108		140
109	=item AnyEvent::Log::log $level, $msg[, @args]	141	=item AnyEvent::Log::log $level, $msg[, @args]
110		142
111	Requests logging of the given C<$msg> with the given log level (1..9).	143	Requests logging of the given C<$msg> with the given log level.
112	You can also use the following strings as log level: C<fatal> (1),
113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114	C<info> (7), C<debug> (8), C<trace> (9).
115		144
116	For C<fatal> log levels, the program will abort.	145	For C<fatal> log levels, the program will abort.
117		146
118	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	147	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
119	C<$msg> is interpreted as an sprintf format string.	148	C<$msg> is interpreted as an sprintf format string.
…		…
152		181
153	=cut	182	=cut
154		183
155	# also allow syslog equivalent names	184	# also allow syslog equivalent names
156	our %STR2LEVEL = (	185	our %STR2LEVEL = (
157	fatal => 1, emerg => 1,	186	fatal => 1, emerg => 1, exit => 1,
158	alert => 2,	187	alert => 2,
159	critical => 3, crit => 3,	188	critical => 3, crit => 3,
160	error => 4, err => 4,	189	error => 4, err => 4, die => 4,
161	warn => 5, warning => 5,	190	warn => 5, warning => 5,
162	note => 6, notice => 6,	191	note => 6, notice => 6,
163	info => 7,	192	info => 7,
164	debug => 8,	193	debug => 8,
165	trace => 9,	194	trace => 9,
…		…
215	};	244	};
216		245
217	# format msg	246	# format msg
218	my $str = $ctx->[4]	247	my $str = $ctx->[4]
219	? $ctx->[4]($now, $_[0], $level, $format)	248	? $ctx->[4]($now, $_[0], $level, $format)
220	: $fmt \|\|= _format $now, $_[0], $level, $format;	249	: ($fmt \|\|= _format $now, $_[0], $level, $format);
221		250
222	$ctx->[3]($str);	251	$ctx->[3]($str, $_[0], $level)
		252	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		253	} else {
		254	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
223	}	255	}
224
225	# not masked, not consumed - propagate to parent contexts
226	push @ctx, values %{ $ctx->[2] };
227	}	256	}
228	}	257	}
229	while $ctx = pop @ctx;	258	while $ctx = pop @ctx;
230		259
231	exit 1 if $level <= 1;	260	exit 1 if $level <= 1;
…		…
275	# and later in your program	304	# and later in your program
276	$debug_log->("yo, stuff here") if $debug;	305	$debug_log->("yo, stuff here") if $debug;
277		306
278	$debug and $debug_log->("123");	307	$debug and $debug_log->("123");
279		308
280	Note: currently the enabled var is always true - that will be fixed in a
281	future version :)
282
283	=cut	309	=cut
284		310
285	our %LOGGER;	311	our %LOGGER;
286		312
287	# re-assess logging status for all loggers	313	# re-assess logging status for all loggers
288	sub _reassess {	314	sub _reassess {
		315	local $SIG{__DIE__};
		316	my $die = sub { die };
		317
289	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	318	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
290	my ($ctx, $level, $renabled) = @$_;	319	my ($ctx, $level, $renabled) = @$_;
291		320
292	# to detect whether a message would be logged, we # actually	321	# to detect whether a message would be logged, we actually
293	# 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
294	# sure that the logging decision is correct :)	323	# sure that the logging decision is correct :)
295		324
296	$$renabled = !eval {	325	$$renabled = !eval {
297	local $SIG{__DIE__};
298
299	_log $ctx, $level, sub { die };	326	_log $ctx, $level, $die;
300		327
301	1	328	1
302	};	329	};
303
304	$$renabled = 1; # TODO
305	}	330	}
306	}	331	}
307		332
308	sub _logger($;$) {	333	sub _logger {
309	my ($ctx, $level, $renabled) = @_;	334	my ($ctx, $level, $renabled) = @_;
310
311	$renabled \|\|= \my $enabled;
312		335
313	$$renabled = 1;	336	$$renabled = 1;
314		337
315	my $logger = [$ctx, $level, $renabled];	338	my $logger = [$ctx, $level, $renabled];
316		339
…		…
356	timestamp, context, level and string message and formats it in the way	379	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	380	it should be logged) and a logging callback (which is responsible for
358	actually logging the formatted message and telling C<AnyEvent::Log>	381	actually logging the formatted message and telling C<AnyEvent::Log>
359	whether it has consumed the message, or whether it should be propagated).	382	whether it has consumed the message, or whether it should be propagated).
360		383
361	For propagation, a context can have any number of attached I<parent	384	For propagation, a context can have any number of attached I<slave
362	contexts>. Any message that is neither masked by the logging mask nor	385	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	386	masked by the logging callback returning true will be passed to all slave
364	contexts.	387	contexts.
365		388
366	Each call to a logging function will log the message at most once per	389	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	390	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.	391	message can arrive at the same context via multiple paths.
…		…
372	By default, all logging contexts have an full set of log levels ("all"), a	395	By default, all logging contexts have an full set of log levels ("all"), a
373	disabled logging callback and the default formatting callback.	396	disabled logging callback and the default formatting callback.
374		397
375	Package contexts have the package name as logging title by default.	398	Package contexts have the package name as logging title by default.
376		399
377	They have exactly one parent - the context of the "parent" package. The	400	They have exactly one slave - the context of the "parent" package. The
378	parent package is simply defined to be the package name without the last	401	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>,	402	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
380	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the	403	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
381	exception of the rule - just like the parent of any package name in	404	exception of the rule - just like the "parent" of any single-component
382	Perl is C<main>, the default parent of any toplevel package context is	405	package name in Perl is C<main>, the default slave of any top-level
383	C<AnyEvent::Log::Top>.	406	package context is C<$AnyEvent::Log::COLLECT>.
384		407
385	Since perl packages form only an approximate hierarchy, this parent	408	Since perl packages form only an approximate hierarchy, this slave
386	context can of course be removed.	409	context can of course be removed.
387		410
388	All other (anonymous) contexts have no parents and an empty title by	411	All other (anonymous) contexts have no slaves and an empty title by
389	default.	412	default.
390		413
391	When the module is loaded it creates the default context called	414	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
392	C<AnyEvent::Log::Default>, which simply logs everything to STDERR and	415	context that simply logs everything via C<warn>, without propagating
393	doesn't propagate anything anywhere by default. The purpose of the default	416	anything anywhere by default. The purpose of this context is to provide
394	context is to provide a convenient place to override the global logging	417	a convenient place to override the global logging target or to attach
395	target or to attach additional log targets. It's not meant for filtering.	418	additional log targets. It's not meant for filtering.
396		419
397	It then creates the root context called C<AnyEvent::Log::Root> and	420	It then creates the C<$AnyEvent::Log::FILTER> context whose
398	sets its log level set to all levels up to the one specified by	421	purpose is to suppress all messages with priority higher
399	C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the default logging	422	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
400	context to it. The purpose of the root context is to simply provide	423	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
401	filtering according to some global log level.	424	is to simply provide filtering according to some global log level.
402		425
403	Finally it creates the toplevel package context called	426	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
404	C<AnyEvent::Log::Top> and attached the root context but otherwise leaves	427	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
405	it at default config. It's purpose is simply to collect all log messages	428	leaves it at default config. Its purpose is simply to collect all log
406	system-wide.	429	messages system-wide.
407		430
408	These three special contexts can also be referred to by the names	431	The hierarchy is then:
409	C<AE::Log::Default>, C<AE::Log::Root> and C<AE::Log::Top>.
410		432
		433	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		434
411	The effect of all this is that log messages, by default, wander up	435	The effect of all this is that log messages, by default, wander up to the
412	to the root context where log messages with lower priority then	436	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		437	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
413	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the	438	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
414	AnyEvent::Log::Default context to be logged to STDERR.	439	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
415		440
416	Splitting the top level context into three contexts makes it easy to set	441	This makes it easy to set a global logging level (by modifying $FILTER),
417	a global logging level (by modifying the root context), but still allow	442	but still allow other contexts to send, for example, their debug and trace
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	443	messages to the $LOG target despite the global logging level, or to attach
420	log targets that log messages, regardless of the global logging level.	444	additional log targets that log messages, regardless of the global logging
		445	level.
421		446
422	It also makes it easy to replace the default STDERR-logger by something	447	It also makes it easy to modify the default warn-logger ($LOG) to
423	that logs to a file, or to attach additional logging targets.	448	something that logs to a file, or to attach additional logging targets
		449	(such as loggign to a file) by attaching it to $FILTER.
424		450
425	=head2 CREATING/FINDING/DESTROYING CONTEXTS	451	=head2 CREATING/FINDING/DESTROYING CONTEXTS
426		452
427	=over 4	453	=over 4
428		454
…		…
450	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	476	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
451	}	477	}
452		478
453	=item AnyEvent::Log::reset	479	=item AnyEvent::Log::reset
454		480
455	Deletes all contexts and recreates the default hierarchy, i.e. resets the	481	Resets all package contexts and recreates the default hierarchy if
456	logging subsystem to defaults.	482	necessary, i.e. resets the logging subsystem to defaults, as much as
		483	possible. This process keeps references to contexts held by other parts of
		484	the program intact.
457		485
458	This can be used to implement config-file (re-)loading: before loading a	486	This can be used to implement config-file (re-)loading: before loading a
459	configuration, reset all contexts.	487	configuration, reset all contexts.
460		488
461	=cut	489	=cut
462		490
463	sub reset {	491	sub reset {
464	@$_ = () for values %CTX; # just to be sure - to kill circular logging dependencies	492	# hard to kill complex data structures
465	%CTX = ();	493	# we "recreate" all package loggers and reset the hierarchy
		494	while (my ($k, $v) = each %CTX) {
		495	@$v = ($k, (1 << 10) - 1 - 1, { });
466		496
467	my $default = ctx undef;	497	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
468	$default->title ("AnyEvent::Log::Default");	498	}
		499
		500	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		501	for $LOG, $FILTER, $COLLECT;
		502
		503	$LOG->slaves;
		504	$LOG->title ('$AnyEvent::Log::LOG');
469	$default->log_cb (sub {	505	$LOG->log_cb (sub {
470	print STDERR shift;	506	warn shift;
471	0	507	0
472	});	508	});
473	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $default;
474		509
475	my $root = ctx undef;	510	$FILTER->slaves ($LOG);
476	$root->title ("AnyEvent::Log::Root");	511	$FILTER->title ('$AnyEvent::Log::FILTER');
477	$root->level ($AnyEvent::VERBOSE);	512	$FILTER->level ($AnyEvent::VERBOSE);
478	$root->attach ($default);
479	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $root;
480		513
481	my $top = ctx undef;	514	$COLLECT->slaves ($FILTER);
482	$top->title ("AnyEvent::Log::Top");	515	$COLLECT->title ('$AnyEvent::Log::COLLECT');
483	$top->attach ($root);	516
484	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $top;	517	_reassess;
485	}	518	}
		519
		520	# create the default logger contexts
		521	$LOG = ctx undef;
		522	$FILTER = ctx undef;
		523	$COLLECT = ctx undef;
486		524
487	AnyEvent::Log::reset;	525	AnyEvent::Log::reset;
488		526
		527	# hello, CPAN, please catch me
489	package AnyEvent::Log::Default;	528	package AnyEvent::Log::LOG;
490	package AE::Log::Default;	529	package AE::Log::LOG;
		530	package AnyEvent::Log::FILTER;
		531	package AE::Log::FILTER;
		532	package AnyEvent::Log::COLLECT;
		533	package AE::Log::COLLECT;
		534
491	package AnyEvent::Log::Root;	535	package AnyEvent::Log::Ctx;
492	package AE::Log::Root;	536
493	package AnyEvent::Log::Top;	537	# 0 1 2 3 4
494	package AE::Log::Top;	538	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		539
		540	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		541
		542	This is a convenience constructor that makes it simpler to construct
		543	anonymous logging contexts.
		544
		545	Each key-value pair results in an invocation of the method of the same
		546	name as the key with the value as parameter, unless the value is an
		547	arrayref, in which case it calls the method with the contents of the
		548	array. The methods are called in the same order as specified.
		549
		550	Example: create a new logging context and set both the default logging
		551	level, some slave contexts and a logging callback.
		552
		553	$ctx = new AnyEvent::Log::Ctx
		554	title => "dubious messages",
		555	level => "error",
		556	log_cb => sub { print STDOUT shift; 0 },
		557	slaves => [$ctx1, $ctx, $ctx2],
		558	;
495		559
496	=back	560	=back
497		561
498	=cut	562	=cut
499		563
500	package AnyEvent::Log::Ctx;	564	sub new {
		565	my $class = shift;
501		566
502	# 0 1 2 3 4	567	my $ctx = AnyEvent::Log::ctx undef;
503	# [$title, $level, %$parents, &$logcb, &$fmtcb]	568
		569	while (@_) {
		570	my ($k, $v) = splice @_, 0, 2;
		571	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		572	}
		573
		574	bless $ctx, $class # do we really support subclassing, hmm?
		575	}
		576
504		577
505	=head2 CONFIGURING A LOG CONTEXT	578	=head2 CONFIGURING A LOG CONTEXT
506		579
507	The following methods can be used to configure the logging context.	580	The following methods can be used to configure the logging context.
508		581
…		…
602	AnyEvent::Log::_reassess;	675	AnyEvent::Log::_reassess;
603	}	676	}
604		677
605	=back	678	=back
606		679
607	=head3 PARENT CONTEXTS	680	=head3 SLAVE CONTEXTS
608		681
609	The following methods attach and detach another logging context to a	682	The following methods attach and detach another logging context to a
610	logging context.	683	logging context.
611		684
612	Log messages are propagated to all parent contexts, unless the logging	685	Log messages are propagated to all slave contexts, unless the logging
613	callback consumes the message.	686	callback consumes the message.
614		687
615	=over 4	688	=over 4
616		689
617	=item $ctx->attach ($ctx2[, $ctx3...])	690	=item $ctx->attach ($ctx2[, $ctx3...])
618		691
619	Attaches the given contexts as parents to this context. It is not an error	692	Attaches the given contexts as slaves to this context. It is not an error
620	to add a context twice (the second add will be ignored).	693	to add a context twice (the second add will be ignored).
621		694
622	A context can be specified either as package name or as a context object.	695	A context can be specified either as package name or as a context object.
623		696
624	=item $ctx->detach ($ctx2[, $ctx3...])	697	=item $ctx->detach ($ctx2[, $ctx3...])
625		698
626	Removes the given parents from this context - it's not an error to attempt	699	Removes the given slaves from this context - it's not an error to attempt
627	to remove a context that hasn't been added.	700	to remove a context that hasn't been added.
628		701
629	A context can be specified either as package name or as a context object.	702	A context can be specified either as package name or as a context object.
630		703
631	=item $ctx->parents ($ctx2[, $ctx3...])	704	=item $ctx->slaves ($ctx2[, $ctx3...])
632		705
633	Replaces all parents attached to this context by the ones given.	706	Replaces all slaves attached to this context by the ones given.
634		707
635	=cut	708	=cut
636		709
637	sub attach {	710	sub attach {
638	my $ctx = shift;	711	my $ctx = shift;
…		…
646		719
647	delete $ctx->[2]{$_+0}	720	delete $ctx->[2]{$_+0}
648	for map { AnyEvent::Log::ctx $_ } @_;	721	for map { AnyEvent::Log::ctx $_ } @_;
649	}	722	}
650		723
651	sub parents {	724	sub slaves {
652	undef $_[0][2];	725	undef $_[0][2];
653	&attach;	726	&attach;
654	}	727	}
655		728
656	=back	729	=back
657		730
658	=head3 MESSAGE LOGGING	731	=head3 LOG TARGETS
659		732
660	The following methods configure how the logging context actually does	733	The following methods configure how the logging context actually does
661	the logging (which consists of formatting the message and printing it or	734	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	735	whatever it wants to do with it).
663	directly to a context, without going via your package context.
664		736
665	=over 4	737	=over 4
666		738
667	=item $ctx->log_cb ($cb->($str))	739	=item $ctx->log_cb ($cb->($str, $orig_ctx, $level))
668		740
669	Replaces the logging callback on the context (C<undef> disables the	741	Replaces the logging callback on the context (C<undef> disables the
670	logging callback).	742	logging callback).
671		743
672	The logging callback is responsible for handling formatted log messages	744	The logging callback is responsible for handling formatted log messages
673	(see C<fmt_cb> below) - normally simple text strings that end with a	745	(see C<fmt_cb> below) - normally simple text strings that end with a
674	newline (and are possibly multiline themselves).	746	newline (and are possibly multiline themselves). In addition to the
		747	message, which is often the only argument you need to look at, it is
		748	passed the numeric log level and originating context.
675		749
676	It also has to return true iff it has consumed the log message, and false	750	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	751	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.	752	slave context. When in doubt, return C<0> from your logging callback.
679		753
680	Example: a very simple logging callback, simply dump the message to STDOUT	754	Example: a very simple logging callback, simply dump the message to STDOUT
681	and do not consume it.	755	and do not consume it.
682		756
683	$ctx->log_cb (sub { print STDERR shift; 0 });	757	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
691	your program.	765	your program.
692		766
693	$ctx->levels ("debug", "trace");	767	$ctx->levels ("debug", "trace");
694	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	768	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
695		769
		770	=item $ctx->log_to_file ($path)
		771
		772	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		773
		774	=item $ctx->log_to_path ($path)
		775
		776	Same as C<< ->log_to_file >>, but opens the file for each message. This
		777	is much slower, but allows you to change/move/rename/delete the file at
		778	basically any time.
		779
		780	=item $ctx->log_to_syslog ([$log_flags])
		781
		782	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
		783	the others in the obvious way. If specified, then the C<$log_flags> are
		784	simply or'ed onto the priority argument and can contain any C<LOG_xxx>
		785	flags valid for Sys::Syslog::syslog, except for the priority levels.
		786
		787	Note that the default logging format includes a verbose timestamp, which
		788	is not so suited for syslog, so a simpler C<fmt_cb> might be useful:
		789
		790	$ctx->log_to_syslog;
		791	$ctx->fmt_cb (sub { "($_[1][0]) $_[3]" });
		792
696	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	793	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
697		794
698	Replaces the formatting callback on the context (C<undef> restores the	795	Replaces the formatting callback on the context (C<undef> restores the
699	default formatter).	796	default formatter).
700		797
701	The callback is passed the (possibly fractional) timestamp, the original	798	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	799	logging context, the (numeric) logging level and the raw message string
703	return a formatted log message. In most cases this will be a string, but	800	and needs to return a formatted log message. In most cases this will be a
704	it could just as well be an array reference that just stores the values.	801	string, but it could just as well be an array reference that just stores
		802	the values.
		803
		804	If, for some reaosn, you want to use C<caller> to find out more baout the
		805	logger then you should walk up the call stack until you are no longer
		806	inside the C<AnyEvent::Log> package.
705		807
706	Example: format just the raw message, with numeric log level in angle	808	Example: format just the raw message, with numeric log level in angle
707	brackets.	809	brackets.
708		810
709	$ctx->fmt_cb (sub {	811	$ctx->fmt_cb (sub {
…		…
740	my ($ctx, $cb) = @_;	842	my ($ctx, $cb) = @_;
741		843
742	$ctx->[4] = $cb;	844	$ctx->[4] = $cb;
743	}	845	}
744		846
		847	sub log_to_file {
		848	my ($ctx, $path) = @_;
		849
		850	open my $fh, ">>", $path
		851	or die "$path: $!";
		852
		853	$ctx->log_cb (sub {
		854	syswrite $fh, shift;
		855	0
		856	});
		857	}
		858
		859	sub log_to_file {
		860	my ($ctx, $path) = @_;
		861
		862	$ctx->log_cb (sub {
		863	open my $fh, ">>", $path
		864	or die "$path: $!";
		865
		866	syswrite $fh, shift;
		867	0
		868	});
		869	}
		870
		871	sub log_to_syslog {
		872	my ($ctx, $flags) = @_;
		873
		874	require Sys::Syslog;
		875
		876	$ctx->log_cb (sub {
		877	my $lvl = $_[2] < 9 ? $_[2] : 8;
		878
		879	Sys::Syslog::syslog ($flags \| ($lvl - 1), $_)
		880	for split /\n/, shift;
		881
		882	0
		883	});
		884	}
		885
		886	=back
		887
		888	=head3 MESSAGE LOGGING
		889
		890	These methods allow you to log messages directly to a context, without
		891	going via your package context.
		892
		893	=over 4
		894
745	=item $ctx->log ($level, $msg[, @params])	895	=item $ctx->log ($level, $msg[, @params])
746		896
747	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	897	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
748		898
749	=item $logger = $ctx->logger ($level[, \$enabled])	899	=item $logger = $ctx->logger ($level[, \$enabled])
…		…
758		908
759	1;	909	1;
760		910
761	=back	911	=back
762		912
		913	=head1 EXAMPLES
		914
		915	This section shows some common configurations.
		916
		917	=over 4
		918
		919	=item Setting the global logging level.
		920
		921	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		922	running your program, or modify the log level of the root context:
		923
		924	PERL_ANYEVENT_VERBOSE=5 ./myprog
		925
		926	$AnyEvent::Log::FILTER->level ("warn");
		927
		928	=item Append all messages to a file instead of sending them to STDERR.
		929
		930	This is affected by the global logging level.
		931
		932	$AnyEvent::Log::LOG->log_to_file ($path); (sub {
		933
		934	=item Write all messages with priority C<error> and higher to a file.
		935
		936	This writes them only when the global logging level allows it, because
		937	it is attached to the default context which is invoked I<after> global
		938	filtering.
		939
		940	$AnyEvent::Log::FILTER->attach
		941	new AnyEvent::Log::Ctx log_to_file => $path);
		942
		943	This writes them regardless of the global logging level, because it is
		944	attached to the toplevel context, which receives all messages I<before>
		945	the global filtering.
		946
		947	$AnyEvent::Log::COLLECT->attach (
		948	new AnyEvent::Log::Ctx log_to_file => $path);
		949
		950	In both cases, messages are still written to STDERR.
		951
		952	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		953
		954	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		955	context - this simply circumvents the global filtering for trace messages.
		956
		957	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		958	$debug->attach ($AnyEvent::Log::LOG);
		959
		960	This of course works for any package, not just L<AnyEvent::Debug>, but
		961	assumes the log level for AnyEvent::Debug hasn't been changed from the
		962	default.
		963
		964	=back
		965
763	=head1 AUTHOR	966	=head1 AUTHOR
764		967
765	Marc Lehmann <schmorp@schmorp.de>	968	Marc Lehmann <schmorp@schmorp.de>
766	http://home.schmorp.de/	969	http://home.schmorp.de/
767		970

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.11 by root, Sat Aug 20 01:03:09 2011 UTC vs. Revision 1.20 by root, Sat Aug 20 22:27:07 2011 UTC

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Revision 1.20 by root, Sat Aug 20 22:27:07 2011 UTC