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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.4 by root, Wed Aug 17 02:50:35 2011 UTC vs.
Revision 1.31 by root, Thu Aug 25 03:08:48 2011 UTC

…		…
2		2
3	AnyEvent::Log - simple logging "framework"	3	AnyEvent::Log - simple logging "framework"
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
		7	Simple uses:
		8
		9	use AnyEvent;
		10
		11	AE::log debug => "hit my knee";
		12	AE::log warn => "it's a bit too hot";
		13	AE::log error => "the flag was false!";
		14	AE::log fatal => "the bit toggled! run!"; # never returns
		15
		16	"Complex" uses (for speed sensitive code):
		17
7	use AnyEvent::Log;	18	use AnyEvent::Log;
		19
		20	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
		21
		22	$tracer->("i am here") if $trace;
		23	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
		24
		25	Configuration (also look at the EXAMPLES section):
		26
		27	# set logging for the current package to errors and higher only
		28	AnyEvent::Log::ctx->level ("error");
		29
		30	# set logging level to suppress anything below "notice"
		31	$AnyEvent::Log::FILTER->level ("notice");
		32
		33	# send all critical and higher priority messages to syslog,
		34	# regardless of (most) other settings
		35	$AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
		36	level => "critical",
		37	log_to_syslog => 0,
		38	);
8		39
9	=head1 DESCRIPTION	40	=head1 DESCRIPTION
10		41
11	This module implements a relatively simple "logging framework". It doesn't	42	This module implements a relatively simple "logging framework". It doesn't
12	attempt to be "the" logging solution or even "a" logging solution for	43	attempt to be "the" logging solution or even "a" logging solution for
13	AnyEvent - AnyEvent simply creates logging messages internally, and this	44	AnyEvent - AnyEvent simply creates logging messages internally, and this
14	module more or less exposes the mechanism, with some extra spiff to allow	45	module more or less exposes the mechanism, with some extra spiff to allow
15	using it from other modules as well.	46	using it from other modules as well.
16		47
17	Remember that the default verbosity level is C<0>, so nothing	48	Remember that the default verbosity level is C<0> (C<off>), so nothing
18	will be logged, ever, unless you set C<$Anyvent::VERBOSE> or	49	will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
19	C<PERL_ANYEVENT_VERBOSE> to a higher number.	50	before starting your program, or change the logging level at runtime with
		51	something like:
20		52
21	Possible future extensions are to allow custom log targets (where the	53	use AnyEvent::Log;
22	level is an object), log filtering based on package, formatting, aliasing	54	AnyEvent::Log::FILTER->level ("info");
23	or package groups.
24		55
		56	The design goal behind this module was to keep it simple (and small),
		57	but make it powerful enough to be potentially useful for any module, and
		58	extensive enough for the most common tasks, such as logging to multiple
		59	targets, or being able to log into a database.
		60
		61	The amount of documentation might indicate otherwise, but the module is
		62	still just below 300 lines of code.
		63
		64	=head1 LOGGING LEVELS
		65
		66	Logging levels in this module range from C<1> (highest priority) to C<9>
		67	(lowest priority). Note that the lowest numerical value is the highest
		68	priority, so when this document says "higher priority" it means "lower
		69	numerical value".
		70
		71	Instead of specifying levels by name you can also specify them by aliases:
		72
		73	LVL NAME SYSLOG PERL NOTE
		74	1 fatal emerg exit aborts program!
		75	2 alert
		76	3 critical crit
		77	4 error err die
		78	5 warn warning
		79	6 note notice
		80	7 info
		81	8 debug
		82	9 trace
		83
		84	As you can see, some logging levels have multiple aliases - the first one
		85	is the "official" name, the second one the "syslog" name (if it differs)
		86	and the third one the "perl" name, suggesting that you log C<die> messages
		87	at C<error> priority.
		88
		89	You can normally only log a single message at highest priority level
		90	(C<1>, C<fatal>), because logging a fatal message will also quit the
		91	program - so use it sparingly :)
		92
		93	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		94	or C<all> - these are only valid in the methods they are documented for.
		95
25	=head1 LOG FUNCTIONS	96	=head1 LOGGING FUNCTIONS
26		97
27	These functions allow you to log messages. They always use the caller's	98	These functions allow you to log messages. They always use the caller's
28	package as a "logging module/source". Also, The main logging function is	99	package as a "logging context". Also, the main logging function C<log> is
29	easily available as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent>	100	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
30	module is loaded.	101	loaded.
31		102
32	=over 4	103	=over 4
33		104
34	=cut	105	=cut
35		106
…		…
38	use Carp ();	109	use Carp ();
39	use POSIX ();	110	use POSIX ();
40		111
41	use AnyEvent (); BEGIN { AnyEvent::common_sense }	112	use AnyEvent (); BEGIN { AnyEvent::common_sense }
42	use AnyEvent::Util ();	113	use AnyEvent::Util ();
		114
		115	our $VERSION = $AnyEvent::VERSION;
		116
		117	our ($COLLECT, $FILTER, $LOG);
43		118
44	our ($now_int, $now_str1, $now_str2);	119	our ($now_int, $now_str1, $now_str2);
45		120
46	# Format Time, not public - yet?	121	# Format Time, not public - yet?
47	sub ft($) {	122	sub ft($) {
…		…
52	if $now_int != $i;	127	if $now_int != $i;
53		128
54	"$now_str1$f$now_str2"	129	"$now_str1$f$now_str2"
55	}	130	}
56		131
57	our %CFG; #TODO	132	our %CTX; # all package contexts
		133
		134	# creates a default package context object for the given package
		135	sub _pkg_ctx($) {
		136	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
		137
		138	# link "parent" package
		139	my $parent = $_[0] =~ /^(.+)::/
		140	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		141	: $COLLECT;
		142
		143	$ctx->[2]{$parent+0} = $parent;
		144
		145	$ctx
		146	}
58		147
59	=item AnyEvent::Log::log $level, $msg[, @args]	148	=item AnyEvent::Log::log $level, $msg[, @args]
60		149
61	Requests logging of the given C<$msg> with the given log level (1..9).	150	Requests logging of the given C<$msg> with the given log level, and
62	You can also use the following strings as log level: C<fatal> (1),	151	returns true if the message was logged I<somewhere>.
63	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
64	C<info> (7), C<debug> (8), C<trace> (9).
65		152
66	For C<fatal> log levels, the program will abort.	153	For C<fatal> log levels, the program will abort.
67		154
68	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	155	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
69	C<$msg> is interpreted as an sprintf format string.	156	C<$msg> is interpreted as an sprintf format string.
…		…
75	supposed to return the message. It will be called only then the message	162	supposed to return the message. It will be called only then the message
76	actually gets logged, which is useful if it is costly to create the	163	actually gets logged, which is useful if it is costly to create the
77	message in the first place.	164	message in the first place.
78		165
79	Whether the given message will be logged depends on the maximum log level	166	Whether the given message will be logged depends on the maximum log level
80	and the caller's package.	167	and the caller's package. The return value can be used to ensure that
		168	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		169	runtime error it tries to log it at C<die> level, but if that message is
		170	lost it simply uses warn.
81		171
82	Note that you can (and should) call this function as C<AnyEvent::log> or	172	Note that you can (and should) call this function as C<AnyEvent::log> or
83	C<AE::log>, without C<use>-ing this module if possible, as those functions	173	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
84	will laod the logging module on demand only.	174	need any additional functionality), as those functions will load the
		175	logging module on demand only. They are also much shorter to write.
		176
		177	Also, if you optionally generate a lot of debug messages (such as when
		178	tracing some code), you should look into using a logger callback and a
		179	boolean enabler (see C<logger>, below).
85		180
86	Example: log something at error level.	181	Example: log something at error level.
87		182
88	AE::log error => "something";	183	AE::log error => "something";
89		184
…		…
97		192
98	=cut	193	=cut
99		194
100	# also allow syslog equivalent names	195	# also allow syslog equivalent names
101	our %STR2LEVEL = (	196	our %STR2LEVEL = (
102	fatal => 1, emerg => 1,	197	fatal => 1, emerg => 1, exit => 1,
103	alert => 2,	198	alert => 2,
104	critical => 3, crit => 3,	199	critical => 3, crit => 3,
105	error => 4, err => 4,	200	error => 4, err => 4, die => 4,
106	warn => 5, warning => 5,	201	warn => 5, warning => 5,
107	note => 6, notice => 6,	202	note => 6, notice => 6,
108	info => 7,	203	info => 7,
109	debug => 8,	204	debug => 8,
110	trace => 9,	205	trace => 9,
111	);	206	);
112		207
113	sub now () { time }	208	sub now () { time }
		209
114	AnyEvent::post_detect {	210	AnyEvent::post_detect {
115	*now = \&AE::now;	211	*now = \&AE::now;
116	};	212	};
117		213
118	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	214	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
119		215
		216	# time, ctx, level, msg
		217	sub _format($$$$) {
		218	my $ts = ft $_[0];
		219	my $ct = " ";
		220
		221	my @res;
		222
		223	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		224	push @res, "$ts$ct$_\n";
		225	$ct = " + ";
		226	}
		227
		228	join "", @res
		229	}
		230
120	sub _log {	231	sub _log {
121	my ($pkg, $targ, $msg, @args) = @_;	232	my ($ctx, $level, $format, @args) = @_;
122		233
123	my $level = ref $targ ? die "Can't use reference as logging level (yet)"	234	$level = $level > 0 && $level <= 9
124	: $targ > 0 && $targ <= 9 ? $targ+0	235	? $level+0
125	: $STR2LEVEL{$targ} \|\| Carp::croak "$targ: not a valid logging level, caught";	236	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
126		237
127	#TODO: find actual targets, see if we even have to log	238	my $mask = 1 << $level;
128		239
129	return unless $level <= $AnyEvent::VERBOSE;	240	my ($success, %seen, @ctx, $now, $fmt);
130		241
131	$msg = $msg->() if ref $msg;	242	do
132	$msg = sprintf $msg, @args if @args;	243	{
133	$msg =~ s/\n$//;	244	# skip if masked
		245	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		246	if ($ctx->[3]) {
		247	# logging target found
134		248
135	# now we have a message, log it	249	# now get raw message, unless we have it already
		250	unless ($now) {
		251	$format = $format->() if ref $format;
		252	$format = sprintf $format, @args if @args;
		253	$format =~ s/\n$//;
		254	$now = now;
		255	};
136		256
137	# TODO: writers/processors/filters/formatters?	257	# format msg
		258	my $str = $ctx->[4]
		259	? $ctx->[4]($now, $_[0], $level, $format)
		260	: ($fmt \|\|= _format $now, $_[0], $level, $format);
138		261
139	$msg = sprintf "%-5s %s: %s", $LEVEL2STR[$level], $pkg, $msg;	262	$success = 1;
140	my $pfx = ft now;
141		263
142	for (split /\n/, $msg) {	264	$ctx->[3]($str)
143	printf STDERR "$pfx $_\n";	265	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
144	$pfx = "\t";	266	} else {
145	}	267	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		268	}
		269	}
		270	}
		271	while $ctx = pop @ctx;
146		272
147	exit 1 if $level <= 1;	273	exit 1 if $level <= 1;
		274
		275	$success
148	}	276	}
149		277
150	sub log($$;@) {	278	sub log($$;@) {
151	_log +(caller)[0], @_;	279	_log
		280	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		281	@_;
152	}	282	}
153		283
154	AnyEvent::log = AE::log = \&log;	284	AnyEvent::log = AE::log = \&log;
155		285
156	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	286	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
157		287
158	Creates a code reference that, when called, acts as if the	288	Creates a code reference that, when called, acts as if the
159	C<AnyEvent::Log::log> function was called at this point with the givne	289	C<AnyEvent::Log::log> function was called at this point with the given
160	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	290	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
161	the C<AnyEvent::Log::log> function:	291	the C<AnyEvent::Log::log> function:
162		292
163	my $debug_log = AnyEvent::Log::logger "debug";	293	my $debug_log = AnyEvent::Log::logger "debug";
164		294
…		…
189	# and later in your program	319	# and later in your program
190	$debug_log->("yo, stuff here") if $debug;	320	$debug_log->("yo, stuff here") if $debug;
191		321
192	$debug and $debug_log->("123");	322	$debug and $debug_log->("123");
193		323
194	Note: currently the enabled var is always true - that will be fixed in a
195	future version :)
196
197	=cut	324	=cut
198		325
199	our %LOGGER;	326	our %LOGGER;
200		327
201	# re-assess logging status for all loggers	328	# re-assess logging status for all loggers
202	sub _reassess {	329	sub _reassess {
		330	local $SIG{__DIE__};
		331	my $die = sub { die };
		332
203	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	333	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
204	my ($pkg, $level, $renabled) = @$_;	334	my ($ctx, $level, $renabled) = @$_;
205		335
206	# to detetc whether a message would be logged, we # actually	336	# to detect whether a message would be logged, we actually
207	# try to log one and die. this isn't # fast, but we can be	337	# try to log one and die. this isn't fast, but we can be
208	# sure that the logging decision is correct :)	338	# sure that the logging decision is correct :)
209		339
210	$$renabled = !eval {	340	$$renabled = !eval {
211	local $SIG{__DIE__};
212
213	_log $pkg, $level, sub { die };	341	_log $ctx, $level, $die;
214		342
215	1	343	1
216	};	344	};
217
218	$$renabled = 1; # TODO
219	}	345	}
220	}	346	}
221		347
222	sub logger($;$) {	348	sub _logger {
223	my ($level, $renabled) = @_;	349	my ($ctx, $level, $renabled) = @_;
224
225	$renabled \|\|= \my $enabled;
226	my $pkg = (caller)[0];
227		350
228	$$renabled = 1;	351	$$renabled = 1;
229		352
230	my $logger = [$pkg, $level, $renabled];	353	my $logger = [$ctx, $level, $renabled];
231		354
232	$LOGGER{$logger+0} = $logger;	355	$LOGGER{$logger+0} = $logger;
233		356
234	_reassess $logger+0;	357	_reassess $logger+0;
235		358
…		…
239	};	362	};
240		363
241	sub {	364	sub {
242	$guard if 0; # keep guard alive, but don't cause runtime overhead	365	$guard if 0; # keep guard alive, but don't cause runtime overhead
243		366
244	_log $pkg, $level, @_	367	_log $ctx, $level, @_
245	if $$renabled;	368	if $$renabled;
246	}	369	}
247	}	370	}
248		371
249	#TODO	372	sub logger($;$) {
		373	_logger
		374	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		375	@_
		376	}
250		377
251	=back	378	=back
252		379
253	=head1 CONFIGURATION FUNCTIONALITY	380	=head1 LOGGING CONTEXTS
254		381
255	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	382	This module associates every log message with a so-called I<logging
		383	context>, based on the package of the caller. Every perl package has its
		384	own logging context.
		385
		386	A logging context has three major responsibilities: filtering, logging and
		387	propagating the message.
		388
		389	For the first purpose, filtering, each context has a set of logging
		390	levels, called the log level mask. Messages not in the set will be ignored
		391	by this context (masked).
		392
		393	For logging, the context stores a formatting callback (which takes the
		394	timestamp, context, level and string message and formats it in the way
		395	it should be logged) and a logging callback (which is responsible for
		396	actually logging the formatted message and telling C<AnyEvent::Log>
		397	whether it has consumed the message, or whether it should be propagated).
		398
		399	For propagation, a context can have any number of attached I<slave
		400	contexts>. Any message that is neither masked by the logging mask nor
		401	masked by the logging callback returning true will be passed to all slave
		402	contexts.
		403
		404	Each call to a logging function will log the message at most once per
		405	context, so it does not matter (much) if there are cycles or if the
		406	message can arrive at the same context via multiple paths.
		407
		408	=head2 DEFAULTS
		409
		410	By default, all logging contexts have an full set of log levels ("all"), a
		411	disabled logging callback and the default formatting callback.
		412
		413	Package contexts have the package name as logging title by default.
		414
		415	They have exactly one slave - the context of the "parent" package. The
		416	parent package is simply defined to be the package name without the last
		417	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		418	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		419	exception of the rule - just like the "parent" of any single-component
		420	package name in Perl is C<main>, the default slave of any top-level
		421	package context is C<$AnyEvent::Log::COLLECT>.
		422
		423	Since perl packages form only an approximate hierarchy, this slave
		424	context can of course be removed.
		425
		426	All other (anonymous) contexts have no slaves and an empty title by
		427	default.
		428
		429	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
		430	context that simply logs everything via C<warn>, without propagating
		431	anything anywhere by default. The purpose of this context is to provide
		432	a convenient place to override the global logging target or to attach
		433	additional log targets. It's not meant for filtering.
		434
		435	It then creates the C<$AnyEvent::Log::FILTER> context whose
		436	purpose is to suppress all messages with priority higher
		437	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		438	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		439	is to simply provide filtering according to some global log level.
		440
		441	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		442	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		443	leaves it at default config. Its purpose is simply to collect all log
		444	messages system-wide.
		445
		446	The hierarchy is then:
		447
		448	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		449
		450	The effect of all this is that log messages, by default, wander up to the
		451	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		452	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		453	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		454	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
		455
		456	This makes it easy to set a global logging level (by modifying $FILTER),
		457	but still allow other contexts to send, for example, their debug and trace
		458	messages to the $LOG target despite the global logging level, or to attach
		459	additional log targets that log messages, regardless of the global logging
		460	level.
		461
		462	It also makes it easy to modify the default warn-logger ($LOG) to
		463	something that logs to a file, or to attach additional logging targets
		464	(such as loggign to a file) by attaching it to $FILTER.
		465
		466	=head2 CREATING/FINDING/DESTROYING CONTEXTS
256		467
257	=over 4	468	=over 4
258		469
		470	=item $ctx = AnyEvent::Log::ctx [$pkg]
		471
		472	This function creates or returns a logging context (which is an object).
		473
		474	If a package name is given, then the context for that packlage is
		475	returned. If it is called without any arguments, then the context for the
		476	callers package is returned (i.e. the same context as a C<AE::log> call
		477	would use).
		478
		479	If C<undef> is given, then it creates a new anonymous context that is not
		480	tied to any package and is destroyed when no longer referenced.
		481
259	=cut	482	=cut
		483
		484	sub ctx(;$) {
		485	my $pkg = @_ ? shift : (caller)[0];
		486
		487	ref $pkg
		488	? $pkg
		489	: defined $pkg
		490	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
		491	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
		492	}
		493
		494	=item AnyEvent::Log::reset
		495
		496	Resets all package contexts and recreates the default hierarchy if
		497	necessary, i.e. resets the logging subsystem to defaults, as much as
		498	possible. This process keeps references to contexts held by other parts of
		499	the program intact.
		500
		501	This can be used to implement config-file (re-)loading: before loading a
		502	configuration, reset all contexts.
		503
		504	=cut
		505
		506	sub reset {
		507	# hard to kill complex data structures
		508	# we "recreate" all package loggers and reset the hierarchy
		509	while (my ($k, $v) = each %CTX) {
		510	@$v = ($k, (1 << 10) - 1 - 1, { });
		511
		512	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
		513	}
		514
		515	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		516	for $LOG, $FILTER, $COLLECT;
		517
		518	$LOG->slaves;
		519	$LOG->title ('$AnyEvent::Log::LOG');
		520	$LOG->log_to_warn;
		521
		522	$FILTER->slaves ($LOG);
		523	$FILTER->title ('$AnyEvent::Log::FILTER');
		524	$FILTER->level ($AnyEvent::VERBOSE);
		525
		526	$COLLECT->slaves ($FILTER);
		527	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		528
		529	_reassess;
		530	}
		531
		532	# create the default logger contexts
		533	$LOG = ctx undef;
		534	$FILTER = ctx undef;
		535	$COLLECT = ctx undef;
		536
		537	AnyEvent::Log::reset;
		538
		539	# hello, CPAN, please catch me
		540	package AnyEvent::Log::LOG;
		541	package AE::Log::LOG;
		542	package AnyEvent::Log::FILTER;
		543	package AE::Log::FILTER;
		544	package AnyEvent::Log::COLLECT;
		545	package AE::Log::COLLECT;
		546
		547	package AnyEvent::Log::Ctx;
		548
		549	# 0 1 2 3 4
		550	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		551
		552	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		553
		554	This is a convenience constructor that makes it simpler to construct
		555	anonymous logging contexts.
		556
		557	Each key-value pair results in an invocation of the method of the same
		558	name as the key with the value as parameter, unless the value is an
		559	arrayref, in which case it calls the method with the contents of the
		560	array. The methods are called in the same order as specified.
		561
		562	Example: create a new logging context and set both the default logging
		563	level, some slave contexts and a logging callback.
		564
		565	$ctx = new AnyEvent::Log::Ctx
		566	title => "dubious messages",
		567	level => "error",
		568	log_cb => sub { print STDOUT shift; 0 },
		569	slaves => [$ctx1, $ctx, $ctx2],
		570	;
		571
		572	=back
		573
		574	=cut
		575
		576	sub new {
		577	my $class = shift;
		578
		579	my $ctx = AnyEvent::Log::ctx undef;
		580
		581	while (@_) {
		582	my ($k, $v) = splice @_, 0, 2;
		583	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		584	}
		585
		586	bless $ctx, $class # do we really support subclassing, hmm?
		587	}
		588
		589
		590	=head2 CONFIGURING A LOG CONTEXT
		591
		592	The following methods can be used to configure the logging context.
		593
		594	=over 4
		595
		596	=item $ctx->title ([$new_title])
		597
		598	Returns the title of the logging context - this is the package name, for
		599	package contexts, and a user defined string for all others.
		600
		601	If C<$new_title> is given, then it replaces the package name or title.
		602
		603	=cut
		604
		605	sub title {
		606	$_[0][0] = $_[1] if @_ > 1;
		607	$_[0][0]
		608	}
		609
		610	=back
		611
		612	=head3 LOGGING LEVELS
		613
		614	The following methods deal with the logging level set associated with the
		615	log context.
		616
		617	The most common method to use is probably C<< $ctx->level ($level) >>,
		618	which configures the specified and any higher priority levels.
		619
		620	All functions which accept a list of levels also accept the special string
		621	C<all> which expands to all logging levels.
		622
		623	=over 4
		624
		625	=item $ctx->levels ($level[, $level...)
		626
		627	Enables logging for the given levels and disables it for all others.
		628
		629	=item $ctx->level ($level)
		630
		631	Enables logging for the given level and all lower level (higher priority)
		632	ones. In addition to normal logging levels, specifying a level of C<0> or
		633	C<off> disables all logging for this level.
		634
		635	Example: log warnings, errors and higher priority messages.
		636
		637	$ctx->level ("warn");
		638	$ctx->level (5); # same thing, just numeric
		639
		640	=item $ctx->enable ($level[, $level...])
		641
		642	Enables logging for the given levels, leaving all others unchanged.
		643
		644	=item $ctx->disable ($level[, $level...])
		645
		646	Disables logging for the given levels, leaving all others unchanged.
		647
		648	=cut
		649
		650	sub _lvl_lst {
		651	map {
		652	$_ > 0 && $_ <= 9 ? $_+0
		653	: $_ eq "all" ? (1 .. 9)
		654	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
		655	} @_
		656	}
		657
		658	our $NOP_CB = sub { 0 };
		659
		660	sub levels {
		661	my $ctx = shift;
		662	$ctx->[1] = 0;
		663	$ctx->[1] \|= 1 << $_
		664	for &_lvl_lst;
		665	AnyEvent::Log::_reassess;
		666	}
		667
		668	sub level {
		669	my $ctx = shift;
		670	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		671
		672	$ctx->[1] = ((1 << $lvl) - 1) << 1;
		673	AnyEvent::Log::_reassess;
		674	}
		675
		676	sub enable {
		677	my $ctx = shift;
		678	$ctx->[1] \|= 1 << $_
		679	for &_lvl_lst;
		680	AnyEvent::Log::_reassess;
		681	}
		682
		683	sub disable {
		684	my $ctx = shift;
		685	$ctx->[1] &= ~(1 << $_)
		686	for &_lvl_lst;
		687	AnyEvent::Log::_reassess;
		688	}
		689
		690	=back
		691
		692	=head3 SLAVE CONTEXTS
		693
		694	The following methods attach and detach another logging context to a
		695	logging context.
		696
		697	Log messages are propagated to all slave contexts, unless the logging
		698	callback consumes the message.
		699
		700	=over 4
		701
		702	=item $ctx->attach ($ctx2[, $ctx3...])
		703
		704	Attaches the given contexts as slaves to this context. It is not an error
		705	to add a context twice (the second add will be ignored).
		706
		707	A context can be specified either as package name or as a context object.
		708
		709	=item $ctx->detach ($ctx2[, $ctx3...])
		710
		711	Removes the given slaves from this context - it's not an error to attempt
		712	to remove a context that hasn't been added.
		713
		714	A context can be specified either as package name or as a context object.
		715
		716	=item $ctx->slaves ($ctx2[, $ctx3...])
		717
		718	Replaces all slaves attached to this context by the ones given.
		719
		720	=cut
		721
		722	sub attach {
		723	my $ctx = shift;
		724
		725	$ctx->[2]{$_+0} = $_
		726	for map { AnyEvent::Log::ctx $_ } @_;
		727	}
		728
		729	sub detach {
		730	my $ctx = shift;
		731
		732	delete $ctx->[2]{$_+0}
		733	for map { AnyEvent::Log::ctx $_ } @_;
		734	}
		735
		736	sub slaves {
		737	undef $_[0][2];
		738	&attach;
		739	}
		740
		741	=back
		742
		743	=head3 LOG TARGETS
		744
		745	The following methods configure how the logging context actually does
		746	the logging (which consists of formatting the message and printing it or
		747	whatever it wants to do with it).
		748
		749	=over 4
		750
		751	=item $ctx->log_cb ($cb->($str)
		752
		753	Replaces the logging callback on the context (C<undef> disables the
		754	logging callback).
		755
		756	The logging callback is responsible for handling formatted log messages
		757	(see C<fmt_cb> below) - normally simple text strings that end with a
		758	newline (and are possibly multiline themselves).
		759
		760	It also has to return true iff it has consumed the log message, and false
		761	if it hasn't. Consuming a message means that it will not be sent to any
		762	slave context. When in doubt, return C<0> from your logging callback.
		763
		764	Example: a very simple logging callback, simply dump the message to STDOUT
		765	and do not consume it.
		766
		767	$ctx->log_cb (sub { print STDERR shift; 0 });
		768
		769	You can filter messages by having a log callback that simply returns C<1>
		770	and does not do anything with the message, but this counts as "message
		771	being logged" and might not be very efficient.
		772
		773	Example: propagate all messages except for log levels "debug" and
		774	"trace". The messages will still be generated, though, which can slow down
		775	your program.
		776
		777	$ctx->levels ("debug", "trace");
		778	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		779
		780	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
		781
		782	Replaces the formatting callback on the context (C<undef> restores the
		783	default formatter).
		784
		785	The callback is passed the (possibly fractional) timestamp, the original
		786	logging context, the (numeric) logging level and the raw message string
		787	and needs to return a formatted log message. In most cases this will be a
		788	string, but it could just as well be an array reference that just stores
		789	the values.
		790
		791	If, for some reason, you want to use C<caller> to find out more baout the
		792	logger then you should walk up the call stack until you are no longer
		793	inside the C<AnyEvent::Log> package.
		794
		795	Example: format just the raw message, with numeric log level in angle
		796	brackets.
		797
		798	$ctx->fmt_cb (sub {
		799	my ($time, $ctx, $lvl, $msg) = @_;
		800
		801	"<$lvl>$msg\n"
		802	});
		803
		804	Example: return an array reference with just the log values, and use
		805	C<PApp::SQL::sql_exec> to store the emssage in a database.
		806
		807	$ctx->fmt_cb (sub { \@_ });
		808	$ctx->log_cb (sub {
		809	my ($msg) = @_;
		810
		811	sql_exec "insert into log (when, subsys, prio, msg) values (?, ?, ?, ?)",
		812	$msg->[0] + 0,
		813	"$msg->[1]",
		814	$msg->[2] + 0,
		815	"$msg->[3]";
		816
		817	0
		818	});
		819
		820	=item $ctx->log_to_warn
		821
		822	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		823	(usually this logs to STDERR).
		824
		825	=item $ctx->log_to_file ($path)
		826
		827	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		828
		829	=item $ctx->log_to_path ($path)
		830
		831	Same as C<< ->log_to_file >>, but opens the file for each message. This
		832	is much slower, but allows you to change/move/rename/delete the file at
		833	basically any time.
		834
		835	Needless(?) to say, if you do not want to be bitten by some evil person
		836	calling C<chdir>, the path should be absolute. Doesn't help with
		837	C<chroot>, but hey...
		838
		839	=item $ctx->log_to_syslog ([$log_flags])
		840
		841	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
		842	the others in the obvious way. If specified, then the C<$log_flags> are
		843	simply or'ed onto the priority argument and can contain any C<LOG_xxx>
		844	flags valid for Sys::Syslog::syslog, except for the priority levels.
		845
		846	Note that this function also sets a C<fmt_cb> - the logging part requires
		847	an array reference with [$level, $str] as input.
		848
		849	=cut
		850
		851	sub log_cb {
		852	my ($ctx, $cb) = @_;
		853
		854	$ctx->[3] = $cb;
		855	}
		856
		857	sub fmt_cb {
		858	my ($ctx, $cb) = @_;
		859
		860	$ctx->[4] = $cb;
		861	}
		862
		863	sub log_to_warn {
		864	my ($ctx, $path) = @_;
		865
		866	$ctx->log_cb (sub {
		867	warn shift;
		868	0
		869	});
		870	}
		871
		872	sub log_to_file {
		873	my ($ctx, $path) = @_;
		874
		875	open my $fh, ">>", $path
		876	or die "$path: $!";
		877
		878	$ctx->log_cb (sub {
		879	syswrite $fh, shift;
		880	0
		881	});
		882	}
		883
		884	sub log_to_path {
		885	my ($ctx, $path) = @_;
		886
		887	$ctx->log_cb (sub {
		888	open my $fh, ">>", $path
		889	or die "$path: $!";
		890
		891	syswrite $fh, shift;
		892	0
		893	});
		894	}
		895
		896	sub log_to_syslog {
		897	my ($ctx, $flags) = @_;
		898
		899	require Sys::Syslog;
		900
		901	$ctx->fmt_cb (sub {
		902	my $str = $_[3];
		903	$str =~ s/\n(?=.)/\n+ /g;
		904
		905	[$_[2], "($_[1][0]) $str"]
		906	});
		907
		908	$ctx->log_cb (sub {
		909	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		910
		911	Sys::Syslog::syslog ($flags \| ($lvl - 1), $_)
		912	for split /\n/, $_[0][1];
		913
		914	0
		915	});
		916	}
		917
		918	=back
		919
		920	=head3 MESSAGE LOGGING
		921
		922	These methods allow you to log messages directly to a context, without
		923	going via your package context.
		924
		925	=over 4
		926
		927	=item $ctx->log ($level, $msg[, @params])
		928
		929	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		930
		931	=item $logger = $ctx->logger ($level[, \$enabled])
		932
		933	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		934	context.
		935
		936	=cut
		937
		938	*log = \&AnyEvent::Log::_log;
		939	*logger = \&AnyEvent::Log::_logger;
		940
		941	=back
		942
		943	=cut
		944
		945	package AnyEvent::Log;
		946
		947	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		948
		949	Logging can also be configured by setting the environment variable
		950	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		951
		952	The value consists of one or more logging context specifications separated
		953	by C<:> or whitespace. Each logging specification in turn starts with a
		954	context name, followed by C<=>, followed by zero or more comma-separated
		955	configuration directives, here are some examples:
		956
		957	# set default logging level
		958	filter=warn
		959
		960	# log to file instead of to stderr
		961	log=file=/tmp/mylog
		962
		963	# log to file in addition to stderr
		964	log=+%file:%file=file=/tmp/mylog
		965
		966	# enable debug log messages, log warnings and above to syslog
		967	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		968
		969	# log trace messages (only) from AnyEvent::Debug to file
		970	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		971
		972	A context name in the log specification can be any of the following:
		973
		974	=over 4
		975
		976	=item C<collect>, C<filter>, C<log>
		977
		978	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		979	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		980
		981	=item C<%name>
		982
		983	Context names starting with a C<%> are anonymous contexts created when the
		984	name is first mentioned. The difference to package contexts is that by
		985	default they have no attached slaves.
		986
		987	=item a perl package name
		988
		989	Any other string references the logging context associated with the given
		990	Perl C<package>. In the unlikely case where you want to specify a package
		991	context that matches on of the other context name forms, you can add a
		992	C<::> to the package name to force interpretation as a package.
		993
		994	=back
		995
		996	The configuration specifications can be any number of the following:
		997
		998	=over 4
		999
		1000	=item C<stderr>
		1001
		1002	Configures the context to use Perl's C<warn> function (which typically
		1003	logs to C<STDERR>). Works like C<log_to_warn>.
		1004
		1005	=item C<file=>I<path>
		1006
		1007	Configures the context to log to a file with the given path. Works like
		1008	C<log_to_file>.
		1009
		1010	=item C<path=>I<path>
		1011
		1012	Configures the context to log to a file with the given path. Works like
		1013	C<log_to_path>.
		1014
		1015	=item C<syslog> or C<syslog=>I<expr>
		1016
		1017	Configured the context to log to syslog. If I<expr> is given, then it is
		1018	evaluated in the L<Sys::Syslog> package, so you could use:
		1019
		1020	log=syslog=LOG_LOCAL0
		1021
		1022	=item C<nolog>
		1023
		1024	Configures the context to not log anything by itself, which is the
		1025	default. Same as C<< $ctx->log_cb (undef) >>.
		1026
		1027	=item C<0> or C<off>
		1028
		1029	Sets the logging level of the context ot C<0>, i.e. all messages will be
		1030	filtered out.
		1031
		1032	=item C<all>
		1033
		1034	Enables all logging levels, i.e. filtering will effectively be switched
		1035	off (the default).
		1036
		1037	=item C<only>
		1038
		1039	Disables all logging levels, and changes the interpretation of following
		1040	level specifications to enable the specified level only.
		1041
		1042	Example: only enable debug messages for a context.
		1043
		1044	context=only,debug
		1045
		1046	=item C<except>
		1047
		1048	Enables all logging levels, and changes the interpretation of following
		1049	level specifications to disable that level. Rarely used.
		1050
		1051	Example: enable all logging levels except fatal and trace (this is rather
		1052	nonsensical).
		1053
		1054	filter=exept,fatal,trace
		1055
		1056	=item C<level>
		1057
		1058	Enables all logging levels, and changes the interpretation of following
		1059	level specifications to be "that level or any higher priority
		1060	message". This is the default.
		1061
		1062	Example: log anything at or above warn level.
		1063
		1064	filter=warn
		1065
		1066	# or, more verbose
		1067	filter=only,level,warn
		1068
		1069	=item C<1>..C<9>, a logging level name (C<error>, C<debug> etc.)
		1070
		1071	A numeric loglevel or the name of a loglevel will be interpreted according
		1072	to the most recent C<only>, C<except> or C<level> directive. By default,
		1073	specifying a logging level enables that and any higher priority messages.
		1074
		1075	=item C<+>I<context>
		1076
		1077	Adds/attaches the named context as slave to the context.
		1078
		1079	=item C<+>
		1080
		1081	A line C<+> clears the slave list form the context. Anonymous (C<%name>)
		1082	contexts have no slaves by default, but package contexts have the parent
		1083	context as slave by default.
		1084
		1085	Example: log messages from My::Module to a file, do not send them to the
		1086	default log collector.
		1087
		1088	My::Module=+,file=/tmp/mymodulelog
		1089
		1090	=back
		1091
		1092	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1093	usual, so to log to a file containing a comma, colon, backslash and space in the
		1094	filename, you would do this:
		1095
		1096	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1097
		1098	Since whitespace (which includes newlines) is allowed, it is fine to
		1099	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1100
		1101	PERL_ANYEVENT_LOG="
		1102	filter=warn
		1103	AnyEvent::Debug=+%trace
		1104	%trace=only,trace,+log
		1105	" myprog
		1106
		1107	Also, in the unlikely case when you want to concatenate specifications,
		1108	use whitespace as separator, as C<::> will be interpreted as part of a
		1109	module name, an empty spec with two separators:
		1110
		1111	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1112
		1113	=cut
		1114
		1115	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1116	my %anon;
		1117
		1118	my $pkg = sub {
		1119	$_[0] eq "log" ? $LOG
		1120	: $_[0] eq "filter" ? $FILTER
		1121	: $_[0] eq "collect" ? $COLLECT
		1122	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= ctx undef)
		1123	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1124	: die # never reached?
		1125	};
		1126
		1127	/\G[[:space:]]+/gc; # skip initial whitespace
		1128
		1129	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1130	my $ctx = $pkg->($1);
		1131	my $level = "level";
		1132
		1133	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1134	for ("$1") {
		1135	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1136	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1137	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1138	} elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
		1139	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1140	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1141	} elsif ($_ eq "+" ) { $ctx->slaves;
		1142	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1143	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1144	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1145	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1146	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1147	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1148	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1149	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1150	}
		1151	}
		1152
		1153	/\G,/gc or last;
		1154	}
		1155
		1156	/\G[:[:space:]]+/gc or last;
		1157	}
		1158
		1159	/\G[[:space:]]+/gc; # skip trailing whitespace
		1160
		1161	if (/\G(.+)/g) {
		1162	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1163	}
		1164	}
260		1165
261	1;	1166	1;
		1167
		1168	=head1 EXAMPLES
		1169
		1170	This section shows some common configurations, both as code, and as
		1171	C<PERL_ANYEVENT_LOG> string.
		1172
		1173	=over 4
		1174
		1175	=item Setting the global logging level.
		1176
		1177	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1178	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1179	the root context at runtime:
		1180
		1181	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1182
		1183	PERL_ANYEVENT_LOG=log=warn
		1184
		1185	$AnyEvent::Log::FILTER->level ("warn");
		1186
		1187	=item Append all messages to a file instead of sending them to STDERR.
		1188
		1189	This is affected by the global logging level.
		1190
		1191	$AnyEvent::Log::LOG->log_to_file ($path);
		1192
		1193	PERL_ANYEVENT_LOG=log=file=/some/path
		1194
		1195	=item Write all messages with priority C<error> and higher to a file.
		1196
		1197	This writes them only when the global logging level allows it, because
		1198	it is attached to the default context which is invoked I<after> global
		1199	filtering.
		1200
		1201	$AnyEvent::Log::FILTER->attach
		1202	new AnyEvent::Log::Ctx log_to_file => $path);
		1203
		1204	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1205
		1206	This writes them regardless of the global logging level, because it is
		1207	attached to the toplevel context, which receives all messages I<before>
		1208	the global filtering.
		1209
		1210	$AnyEvent::Log::COLLECT->attach (
		1211	new AnyEvent::Log::Ctx log_to_file => $path);
		1212
		1213	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1214
		1215	In both cases, messages are still written to STDERR.
		1216
		1217	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1218
		1219	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1220	context - this simply circumvents the global filtering for trace messages.
		1221
		1222	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1223	$debug->attach ($AnyEvent::Log::LOG);
		1224
		1225	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1226
		1227	This of course works for any package, not just L<AnyEvent::Debug>, but
		1228	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1229	default.
262		1230
263	=back	1231	=back
264		1232
265	=head1 AUTHOR	1233	=head1 AUTHOR
266		1234
267	Marc Lehmann <schmorp@schmorp.de>	1235	Marc Lehmann <schmorp@schmorp.de>
268	http://home.schmorp.de/	1236	http://home.schmorp.de/
269		1237
270	=cut	1238	=cut
		1239

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.4 by root, Wed Aug 17 02:50:35 2011 UTC vs. Revision 1.31 by root, Thu Aug 25 03:08:48 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.4 by root, Wed Aug 17 02:50:35 2011 UTC vs.
Revision 1.31 by root, Thu Aug 25 03:08:48 2011 UTC