[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 1.22 by root, Sun Aug 21 02:19:30 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<$msg> with the given log level, and
112	You can also use the following strings as log level: C<fatal> (1),	144	returns true if the message was logged I<somewhere>.
113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114	C<info> (7), C<debug> (8), C<trace> (9).
115		145
116	For C<fatal> log levels, the program will abort.	146	For C<fatal> log levels, the program will abort.
117		147
118	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	148	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.	149	C<$msg> is interpreted as an sprintf format string.
…		…
125	supposed to return the message. It will be called only then the message	155	supposed to return the message. It will be called only then the message
126	actually gets logged, which is useful if it is costly to create the	156	actually gets logged, which is useful if it is costly to create the
127	message in the first place.	157	message in the first place.
128		158
129	Whether the given message will be logged depends on the maximum log level	159	Whether the given message will be logged depends on the maximum log level
130	and the caller's package.	160	and the caller's package. The return value can be used to ensure that
		161	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		162	runtime error it tries to log it at C<die> level, but if that message is
		163	lost it simply uses warn.
131		164
132	Note that you can (and should) call this function as C<AnyEvent::log> or	165	Note that you can (and should) call this function as C<AnyEvent::log> or
133	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	166	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
134	need any additional functionality), as those functions will load the	167	need any additional functionality), as those functions will load the
135	logging module on demand only. They are also much shorter to write.	168	logging module on demand only. They are also much shorter to write.
…		…
152		185
153	=cut	186	=cut
154		187
155	# also allow syslog equivalent names	188	# also allow syslog equivalent names
156	our %STR2LEVEL = (	189	our %STR2LEVEL = (
157	fatal => 1, emerg => 1,	190	fatal => 1, emerg => 1, exit => 1,
158	alert => 2,	191	alert => 2,
159	critical => 3, crit => 3,	192	critical => 3, crit => 3,
160	error => 4, err => 4,	193	error => 4, err => 4, die => 4,
161	warn => 5, warning => 5,	194	warn => 5, warning => 5,
162	note => 6, notice => 6,	195	note => 6, notice => 6,
163	info => 7,	196	info => 7,
164	debug => 8,	197	debug => 8,
165	trace => 9,	198	trace => 9,
…		…
195	? $level+0	228	? $level+0
196	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	229	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
197		230
198	my $mask = 1 << $level;	231	my $mask = 1 << $level;
199		232
200	my (%seen, @ctx, $now, $fmt);	233	my ($success, %seen, @ctx, $now, $fmt);
201		234
202	do	235	do
203	{	236	{
204	# skip if masked	237	# skip if masked
205	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {	238	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
…		…
215	};	248	};
216		249
217	# format msg	250	# format msg
218	my $str = $ctx->[4]	251	my $str = $ctx->[4]
219	? $ctx->[4]($now, $_[0], $level, $format)	252	? $ctx->[4]($now, $_[0], $level, $format)
220	: $fmt \|\|= _format $now, $_[0], $level, $format;	253	: ($fmt \|\|= _format $now, $_[0], $level, $format);
221		254
		255	$success = 1;
		256
222	$ctx->[3]($str);	257	$ctx->[3]($str)
		258	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		259	} else {
		260	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
223	}	261	}
224
225	# not masked, not consumed - propagate to parent contexts
226	push @ctx, values %{ $ctx->[2] };
227	}	262	}
228	}	263	}
229	while $ctx = pop @ctx;	264	while $ctx = pop @ctx;
230		265
231	exit 1 if $level <= 1;	266	exit 1 if $level <= 1;
		267
		268	$success
232	}	269	}
233		270
234	sub log($$;@) {	271	sub log($$;@) {
235	_log	272	_log
236	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],	273	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
…		…
240	AnyEvent::log = AE::log = \&log;	277	AnyEvent::log = AE::log = \&log;
241		278
242	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	279	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
243		280
244	Creates a code reference that, when called, acts as if the	281	Creates a code reference that, when called, acts as if the
245	C<AnyEvent::Log::log> function was called at this point with the givne	282	C<AnyEvent::Log::log> function was called at this point with the given
246	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	283	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
247	the C<AnyEvent::Log::log> function:	284	the C<AnyEvent::Log::log> function:
248		285
249	my $debug_log = AnyEvent::Log::logger "debug";	286	my $debug_log = AnyEvent::Log::logger "debug";
250		287
…		…
275	# and later in your program	312	# and later in your program
276	$debug_log->("yo, stuff here") if $debug;	313	$debug_log->("yo, stuff here") if $debug;
277		314
278	$debug and $debug_log->("123");	315	$debug and $debug_log->("123");
279		316
280	Note: currently the enabled var is always true - that will be fixed in a
281	future version :)
282
283	=cut	317	=cut
284		318
285	our %LOGGER;	319	our %LOGGER;
286		320
287	# re-assess logging status for all loggers	321	# re-assess logging status for all loggers
288	sub _reassess {	322	sub _reassess {
		323	local $SIG{__DIE__};
		324	my $die = sub { die };
		325
289	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	326	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
290	my ($ctx, $level, $renabled) = @$_;	327	my ($ctx, $level, $renabled) = @$_;
291		328
292	# to detect whether a message would be logged, we # actually	329	# 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	330	# try to log one and die. this isn't fast, but we can be
294	# sure that the logging decision is correct :)	331	# sure that the logging decision is correct :)
295		332
296	$$renabled = !eval {	333	$$renabled = !eval {
297	local $SIG{__DIE__};
298
299	_log $ctx, $level, sub { die };	334	_log $ctx, $level, $die;
300		335
301	1	336	1
302	};	337	};
303
304	$$renabled = 1; # TODO
305	}	338	}
306	}	339	}
307		340
308	sub _logger($;$) {	341	sub _logger {
309	my ($ctx, $level, $renabled) = @_;	342	my ($ctx, $level, $renabled) = @_;
310
311	$renabled \|\|= \my $enabled;
312		343
313	$$renabled = 1;	344	$$renabled = 1;
314		345
315	my $logger = [$ctx, $level, $renabled];	346	my $logger = [$ctx, $level, $renabled];
316		347
…		…
356	timestamp, context, level and string message and formats it in the way	387	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	388	it should be logged) and a logging callback (which is responsible for
358	actually logging the formatted message and telling C<AnyEvent::Log>	389	actually logging the formatted message and telling C<AnyEvent::Log>
359	whether it has consumed the message, or whether it should be propagated).	390	whether it has consumed the message, or whether it should be propagated).
360		391
361	For propagation, a context can have any number of attached I<parent	392	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	393	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	394	masked by the logging callback returning true will be passed to all slave
364	contexts.	395	contexts.
365		396
366	Each call to a logging function will log the message at most once per	397	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	398	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.	399	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	403	By default, all logging contexts have an full set of log levels ("all"), a
373	disabled logging callback and the default formatting callback.	404	disabled logging callback and the default formatting callback.
374		405
375	Package contexts have the package name as logging title by default.	406	Package contexts have the package name as logging title by default.
376		407
377	They have exactly one parent - the context of the "parent" package. The	408	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	409	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>,	410	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
380	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the	411	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	412	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	413	package name in Perl is C<main>, the default slave of any top-level
383	C<AnyEvent::Log::Top>.	414	package context is C<$AnyEvent::Log::COLLECT>.
384		415
385	Since perl packages form only an approximate hierarchy, this parent	416	Since perl packages form only an approximate hierarchy, this slave
386	context can of course be removed.	417	context can of course be removed.
387		418
388	All other (anonymous) contexts have no parents and an empty title by	419	All other (anonymous) contexts have no slaves and an empty title by
389	default.	420	default.
390		421
391	When the module is loaded it creates the default context called	422	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
392	C<AnyEvent::Log::Default>, which simply logs everything to STDERR and	423	context that simply logs everything via C<warn>, without propagating
393	doesn't propagate anything anywhere by default. The purpose of the default	424	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	425	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.	426	additional log targets. It's not meant for filtering.
396		427
397	It then creates the root context called C<AnyEvent::Log::Root> and	428	It then creates the C<$AnyEvent::Log::FILTER> context whose
398	sets its log level set to all levels up to the one specified by	429	purpose is to suppress all messages with priority higher
399	C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the default logging	430	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
400	context to it. The purpose of the root context is to simply provide	431	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
401	filtering according to some global log level.	432	is to simply provide filtering according to some global log level.
402		433
403	Finally it creates the toplevel package context called	434	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
404	C<AnyEvent::Log::Top> and attached the root context but otherwise leaves	435	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
405	it at default config. It's purpose is simply to collect all log messages	436	leaves it at default config. Its purpose is simply to collect all log
406	system-wide.	437	messages system-wide.
407		438
408	These three special contexts can also be referred to by the names	439	The hierarchy is then:
409	C<AE::Log::Default>, C<AE::Log::Root> and C<AE::Log::Top>.
410		440
		441	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		442
411	The effect of all this is that log messages, by default, wander up	443	The effect of all this is that log messages, by default, wander up to the
412	to the root context where log messages with lower priority then	444	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		445	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	446	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
414	AnyEvent::Log::Default context to be logged to STDERR.	447	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
415		448
416	Splitting the top level context into three contexts makes it easy to set	449	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	450	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	451	messages to the $LOG target despite the global logging level, or to attach
420	log targets that log messages, regardless of the global logging level.	452	additional log targets that log messages, regardless of the global logging
		453	level.
421		454
422	It also makes it easy to replace the default STDERR-logger by something	455	It also makes it easy to modify the default warn-logger ($LOG) to
423	that logs to a file, or to attach additional logging targets.	456	something that logs to a file, or to attach additional logging targets
		457	(such as loggign to a file) by attaching it to $FILTER.
424		458
425	=head2 CREATING/FINDING/DESTROYING CONTEXTS	459	=head2 CREATING/FINDING/DESTROYING CONTEXTS
426		460
427	=over 4	461	=over 4
428		462
…		…
450	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	484	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
451	}	485	}
452		486
453	=item AnyEvent::Log::reset	487	=item AnyEvent::Log::reset
454		488
455	Deletes all contexts and recreates the default hierarchy, i.e. resets the	489	Resets all package contexts and recreates the default hierarchy if
456	logging subsystem to defaults.	490	necessary, i.e. resets the logging subsystem to defaults, as much as
		491	possible. This process keeps references to contexts held by other parts of
		492	the program intact.
457		493
458	This can be used to implement config-file (re-)loading: before loading a	494	This can be used to implement config-file (re-)loading: before loading a
459	configuration, reset all contexts.	495	configuration, reset all contexts.
460		496
461	=cut	497	=cut
462		498
463	sub reset {	499	sub reset {
464	@$_ = () for values %CTX; # just to be sure - to kill circular logging dependencies	500	# hard to kill complex data structures
465	%CTX = ();	501	# we "recreate" all package loggers and reset the hierarchy
		502	while (my ($k, $v) = each %CTX) {
		503	@$v = ($k, (1 << 10) - 1 - 1, { });
466		504
467	my $default = ctx undef;	505	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
468	$default->title ("AnyEvent::Log::Default");	506	}
		507
		508	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		509	for $LOG, $FILTER, $COLLECT;
		510
		511	$LOG->slaves;
		512	$LOG->title ('$AnyEvent::Log::LOG');
469	$default->log_cb (sub {	513	$LOG->log_cb (sub {
470	print STDERR shift;	514	warn shift;
471	0	515	0
472	});	516	});
473	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $default;
474		517
475	my $root = ctx undef;	518	$FILTER->slaves ($LOG);
476	$root->title ("AnyEvent::Log::Root");	519	$FILTER->title ('$AnyEvent::Log::FILTER');
477	$root->level ($AnyEvent::VERBOSE);	520	$FILTER->level ($AnyEvent::VERBOSE);
478	$root->attach ($default);
479	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $root;
480		521
481	my $top = ctx undef;	522	$COLLECT->slaves ($FILTER);
482	$top->title ("AnyEvent::Log::Top");	523	$COLLECT->title ('$AnyEvent::Log::COLLECT');
483	$top->attach ($root);	524
484	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $top;	525	_reassess;
485	}	526	}
		527
		528	# create the default logger contexts
		529	$LOG = ctx undef;
		530	$FILTER = ctx undef;
		531	$COLLECT = ctx undef;
486		532
487	AnyEvent::Log::reset;	533	AnyEvent::Log::reset;
488		534
		535	# hello, CPAN, please catch me
489	package AnyEvent::Log::Default;	536	package AnyEvent::Log::LOG;
490	package AE::Log::Default;	537	package AE::Log::LOG;
		538	package AnyEvent::Log::FILTER;
		539	package AE::Log::FILTER;
		540	package AnyEvent::Log::COLLECT;
		541	package AE::Log::COLLECT;
		542
491	package AnyEvent::Log::Root;	543	package AnyEvent::Log::Ctx;
492	package AE::Log::Root;	544
493	package AnyEvent::Log::Top;	545	# 0 1 2 3 4
494	package AE::Log::Top;	546	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		547
		548	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		549
		550	This is a convenience constructor that makes it simpler to construct
		551	anonymous logging contexts.
		552
		553	Each key-value pair results in an invocation of the method of the same
		554	name as the key with the value as parameter, unless the value is an
		555	arrayref, in which case it calls the method with the contents of the
		556	array. The methods are called in the same order as specified.
		557
		558	Example: create a new logging context and set both the default logging
		559	level, some slave contexts and a logging callback.
		560
		561	$ctx = new AnyEvent::Log::Ctx
		562	title => "dubious messages",
		563	level => "error",
		564	log_cb => sub { print STDOUT shift; 0 },
		565	slaves => [$ctx1, $ctx, $ctx2],
		566	;
495		567
496	=back	568	=back
497		569
498	=cut	570	=cut
499		571
500	package AnyEvent::Log::Ctx;	572	sub new {
		573	my $class = shift;
501		574
502	# 0 1 2 3 4	575	my $ctx = AnyEvent::Log::ctx undef;
503	# [$title, $level, %$parents, &$logcb, &$fmtcb]	576
		577	while (@_) {
		578	my ($k, $v) = splice @_, 0, 2;
		579	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		580	}
		581
		582	bless $ctx, $class # do we really support subclassing, hmm?
		583	}
		584
504		585
505	=head2 CONFIGURING A LOG CONTEXT	586	=head2 CONFIGURING A LOG CONTEXT
506		587
507	The following methods can be used to configure the logging context.	588	The following methods can be used to configure the logging context.
508		589
…		…
602	AnyEvent::Log::_reassess;	683	AnyEvent::Log::_reassess;
603	}	684	}
604		685
605	=back	686	=back
606		687
607	=head3 PARENT CONTEXTS	688	=head3 SLAVE CONTEXTS
608		689
609	The following methods attach and detach another logging context to a	690	The following methods attach and detach another logging context to a
610	logging context.	691	logging context.
611		692
612	Log messages are propagated to all parent contexts, unless the logging	693	Log messages are propagated to all slave contexts, unless the logging
613	callback consumes the message.	694	callback consumes the message.
614		695
615	=over 4	696	=over 4
616		697
617	=item $ctx->attach ($ctx2[, $ctx3...])	698	=item $ctx->attach ($ctx2[, $ctx3...])
618		699
619	Attaches the given contexts as parents to this context. It is not an error	700	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).	701	to add a context twice (the second add will be ignored).
621		702
622	A context can be specified either as package name or as a context object.	703	A context can be specified either as package name or as a context object.
623		704
624	=item $ctx->detach ($ctx2[, $ctx3...])	705	=item $ctx->detach ($ctx2[, $ctx3...])
625		706
626	Removes the given parents from this context - it's not an error to attempt	707	Removes the given slaves from this context - it's not an error to attempt
627	to remove a context that hasn't been added.	708	to remove a context that hasn't been added.
628		709
629	A context can be specified either as package name or as a context object.	710	A context can be specified either as package name or as a context object.
630		711
631	=item $ctx->parents ($ctx2[, $ctx3...])	712	=item $ctx->slaves ($ctx2[, $ctx3...])
632		713
633	Replaces all parents attached to this context by the ones given.	714	Replaces all slaves attached to this context by the ones given.
634		715
635	=cut	716	=cut
636		717
637	sub attach {	718	sub attach {
638	my $ctx = shift;	719	my $ctx = shift;
…		…
646		727
647	delete $ctx->[2]{$_+0}	728	delete $ctx->[2]{$_+0}
648	for map { AnyEvent::Log::ctx $_ } @_;	729	for map { AnyEvent::Log::ctx $_ } @_;
649	}	730	}
650		731
651	sub parents {	732	sub slaves {
652	undef $_[0][2];	733	undef $_[0][2];
653	&attach;	734	&attach;
654	}	735	}
655		736
656	=back	737	=back
657		738
658	=head3 MESSAGE LOGGING	739	=head3 LOG TARGETS
659		740
660	The following methods configure how the logging context actually does	741	The following methods configure how the logging context actually does
661	the logging (which consists of formatting the message and printing it or	742	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	743	whatever it wants to do with it).
663	directly to a context, without going via your package context.
664		744
665	=over 4	745	=over 4
666		746
667	=item $ctx->log_cb ($cb->($str))	747	=item $ctx->log_cb ($cb->($str)
668		748
669	Replaces the logging callback on the context (C<undef> disables the	749	Replaces the logging callback on the context (C<undef> disables the
670	logging callback).	750	logging callback).
671		751
672	The logging callback is responsible for handling formatted log messages	752	The logging callback is responsible for handling formatted log messages
673	(see C<fmt_cb> below) - normally simple text strings that end with a	753	(see C<fmt_cb> below) - normally simple text strings that end with a
674	newline (and are possibly multiline themselves).	754	newline (and are possibly multiline themselves).
675		755
676	It also has to return true iff it has consumed the log message, and false	756	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	757	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.	758	slave context. When in doubt, return C<0> from your logging callback.
679		759
680	Example: a very simple logging callback, simply dump the message to STDOUT	760	Example: a very simple logging callback, simply dump the message to STDOUT
681	and do not consume it.	761	and do not consume it.
682		762
683	$ctx->log_cb (sub { print STDERR shift; 0 });	763	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
691	your program.	771	your program.
692		772
693	$ctx->levels ("debug", "trace");	773	$ctx->levels ("debug", "trace");
694	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	774	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
695		775
696	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	776	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
697		777
698	Replaces the formatting callback on the context (C<undef> restores the	778	Replaces the formatting callback on the context (C<undef> restores the
699	default formatter).	779	default formatter).
700		780
701	The callback is passed the (possibly fractional) timestamp, the original	781	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	782	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	783	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.	784	string, but it could just as well be an array reference that just stores
		785	the values.
		786
		787	If, for some reaosn, you want to use C<caller> to find out more baout the
		788	logger then you should walk up the call stack until you are no longer
		789	inside the C<AnyEvent::Log> package.
705		790
706	Example: format just the raw message, with numeric log level in angle	791	Example: format just the raw message, with numeric log level in angle
707	brackets.	792	brackets.
708		793
709	$ctx->fmt_cb (sub {	794	$ctx->fmt_cb (sub {
…		…
726	"$msg->[3]";	811	"$msg->[3]";
727		812
728	0	813	0
729	});	814	});
730		815
		816	=item $ctx->log_to_file ($path)
		817
		818	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		819
		820	=item $ctx->log_to_path ($path)
		821
		822	Same as C<< ->log_to_file >>, but opens the file for each message. This
		823	is much slower, but allows you to change/move/rename/delete the file at
		824	basically any time.
		825
		826	=item $ctx->log_to_syslog ([$log_flags])
		827
		828	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
		829	the others in the obvious way. If specified, then the C<$log_flags> are
		830	simply or'ed onto the priority argument and can contain any C<LOG_xxx>
		831	flags valid for Sys::Syslog::syslog, except for the priority levels.
		832
		833	Note that this function also sets a C<fmt_cb> - the logging part requires
		834	an array reference with [$level, $str] as input.
		835
731	=cut	836	=cut
732		837
733	sub log_cb {	838	sub log_cb {
734	my ($ctx, $cb) = @_;	839	my ($ctx, $cb) = @_;
735		840
…		…
740	my ($ctx, $cb) = @_;	845	my ($ctx, $cb) = @_;
741		846
742	$ctx->[4] = $cb;	847	$ctx->[4] = $cb;
743	}	848	}
744		849
		850	sub log_to_file {
		851	my ($ctx, $path) = @_;
		852
		853	open my $fh, ">>", $path
		854	or die "$path: $!";
		855
		856	$ctx->log_cb (sub {
		857	syswrite $fh, shift;
		858	0
		859	});
		860	}
		861
		862	sub log_to_file {
		863	my ($ctx, $path) = @_;
		864
		865	$ctx->log_cb (sub {
		866	open my $fh, ">>", $path
		867	or die "$path: $!";
		868
		869	syswrite $fh, shift;
		870	0
		871	});
		872	}
		873
		874	sub log_to_syslog {
		875	my ($ctx, $flags) = @_;
		876
		877	require Sys::Syslog;
		878
		879	$ctx->fmt_cb (sub {
		880	my $str = $_[3];
		881	$str =~ s/\n(?=.)/\n+ /g;
		882
		883	[$_[2], "($_[1][0]) $str"]
		884	});
		885
		886	$ctx->log_cb (sub {
		887	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		888
		889	Sys::Syslog::syslog ($flags \| ($lvl - 1), $_)
		890	for split /\n/, $_[0][1];
		891
		892	0
		893	});
		894	}
		895
		896	=back
		897
		898	=head3 MESSAGE LOGGING
		899
		900	These methods allow you to log messages directly to a context, without
		901	going via your package context.
		902
		903	=over 4
		904
745	=item $ctx->log ($level, $msg[, @params])	905	=item $ctx->log ($level, $msg[, @params])
746		906
747	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	907	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
748		908
749	=item $logger = $ctx->logger ($level[, \$enabled])	909	=item $logger = $ctx->logger ($level[, \$enabled])
…		…
758		918
759	1;	919	1;
760		920
761	=back	921	=back
762		922
		923	=head1 EXAMPLES
		924
		925	This section shows some common configurations.
		926
		927	=over 4
		928
		929	=item Setting the global logging level.
		930
		931	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		932	running your program, or modify the log level of the root context:
		933
		934	PERL_ANYEVENT_VERBOSE=5 ./myprog
		935
		936	$AnyEvent::Log::FILTER->level ("warn");
		937
		938	=item Append all messages to a file instead of sending them to STDERR.
		939
		940	This is affected by the global logging level.
		941
		942	$AnyEvent::Log::LOG->log_to_file ($path); (sub {
		943
		944	=item Write all messages with priority C<error> and higher to a file.
		945
		946	This writes them only when the global logging level allows it, because
		947	it is attached to the default context which is invoked I<after> global
		948	filtering.
		949
		950	$AnyEvent::Log::FILTER->attach
		951	new AnyEvent::Log::Ctx log_to_file => $path);
		952
		953	This writes them regardless of the global logging level, because it is
		954	attached to the toplevel context, which receives all messages I<before>
		955	the global filtering.
		956
		957	$AnyEvent::Log::COLLECT->attach (
		958	new AnyEvent::Log::Ctx log_to_file => $path);
		959
		960	In both cases, messages are still written to STDERR.
		961
		962	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		963
		964	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		965	context - this simply circumvents the global filtering for trace messages.
		966
		967	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		968	$debug->attach ($AnyEvent::Log::LOG);
		969
		970	This of course works for any package, not just L<AnyEvent::Debug>, but
		971	assumes the log level for AnyEvent::Debug hasn't been changed from the
		972	default.
		973
		974	=back
		975
763	=head1 AUTHOR	976	=head1 AUTHOR
764		977
765	Marc Lehmann <schmorp@schmorp.de>	978	Marc Lehmann <schmorp@schmorp.de>
766	http://home.schmorp.de/	979	http://home.schmorp.de/
767		980

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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 1.22 by root, Sun Aug 21 02:19:30 2011 UTC

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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 1.22 by root, Sun Aug 21 02:19:30 2011 UTC