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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs.
Revision 1.36 by root, Thu Aug 25 05:39:47 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 module is also usable before AnyEvent itself is initialised, in which
		62	case some of the functionality might be reduced.
		63
		64	The amount of documentation might indicate otherwise, but the runtime part
		65	of the module is still just below 300 lines of code.
		66
		67	=head1 LOGGING LEVELS
		68
		69	Logging levels in this module range from C<1> (highest priority) to C<9>
		70	(lowest priority). Note that the lowest numerical value is the highest
		71	priority, so when this document says "higher priority" it means "lower
		72	numerical value".
		73
		74	Instead of specifying levels by name you can also specify them by aliases:
		75
		76	LVL NAME SYSLOG PERL NOTE
		77	1 fatal emerg exit aborts program!
		78	2 alert
		79	3 critical crit
		80	4 error err die
		81	5 warn warning
		82	6 note notice
		83	7 info
		84	8 debug
		85	9 trace
		86
		87	As you can see, some logging levels have multiple aliases - the first one
		88	is the "official" name, the second one the "syslog" name (if it differs)
		89	and the third one the "perl" name, suggesting that you log C<die> messages
		90	at C<error> priority.
		91
		92	You can normally only log a single message at highest priority level
		93	(C<1>, C<fatal>), because logging a fatal message will also quit the
		94	program - so use it sparingly :)
		95
		96	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		97	or C<all> - these are only valid in the methods they are documented for.
		98
25	=head1 LOG FUNCTIONS	99	=head1 LOGGING FUNCTIONS
26		100
27	These functions allow you to log messages. They always use the caller's	101	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	102	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>	103	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
30	module is loaded.	104	loaded.
31		105
32	=over 4	106	=over 4
33		107
34	=cut	108	=cut
35		109
…		…
38	use Carp ();	112	use Carp ();
39	use POSIX ();	113	use POSIX ();
40		114
41	use AnyEvent (); BEGIN { AnyEvent::common_sense }	115	use AnyEvent (); BEGIN { AnyEvent::common_sense }
42	use AnyEvent::Util ();	116	use AnyEvent::Util ();
		117
		118	our $VERSION = $AnyEvent::VERSION;
		119
		120	our ($COLLECT, $FILTER, $LOG);
43		121
44	our ($now_int, $now_str1, $now_str2);	122	our ($now_int, $now_str1, $now_str2);
45		123
46	# Format Time, not public - yet?	124	# Format Time, not public - yet?
47	sub ft($) {	125	sub ft($) {
…		…
52	if $now_int != $i;	130	if $now_int != $i;
53		131
54	"$now_str1$f$now_str2"	132	"$now_str1$f$now_str2"
55	}	133	}
56		134
57	our %CFG; #TODO	135	our %CTX; # all package contexts
		136
		137	# creates a default package context object for the given package
		138	sub _pkg_ctx($) {
		139	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
		140
		141	# link "parent" package
		142	my $parent = $_[0] =~ /^(.+)::/
		143	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		144	: $COLLECT;
		145
		146	$ctx->[2]{$parent+0} = $parent;
		147
		148	$ctx
		149	}
58		150
59	=item AnyEvent::Log::log $level, $msg[, @args]	151	=item AnyEvent::Log::log $level, $msg[, @args]
60		152
61	Requests logging of the given C<$msg> with the given log level (1..9).	153	Requests logging of the given C<$msg> with the given log level, and
62	You can also use the following strings as log level: C<fatal> (1),	154	returns true if the message was logged I<somewhere>.
63	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
64	C<info> (7), C<debug> (8), C<trace> (9).
65		155
66	For C<fatal> log levels, the program will abort.	156	For C<fatal> log levels, the program will abort.
67		157
68	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	158	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.	159	C<$msg> is interpreted as an sprintf format string.
…		…
75	supposed to return the message. It will be called only then the message	165	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	166	actually gets logged, which is useful if it is costly to create the
77	message in the first place.	167	message in the first place.
78		168
79	Whether the given message will be logged depends on the maximum log level	169	Whether the given message will be logged depends on the maximum log level
80	and the caller's package.	170	and the caller's package. The return value can be used to ensure that
		171	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		172	runtime error it tries to log it at C<die> level, but if that message is
		173	lost it simply uses warn.
81		174
82	Note that you can (and should) call this function as C<AnyEvent::log> or	175	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	176	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.	177	need any additional functionality), as those functions will load the
		178	logging module on demand only. They are also much shorter to write.
		179
		180	Also, if you optionally generate a lot of debug messages (such as when
		181	tracing some code), you should look into using a logger callback and a
		182	boolean enabler (see C<logger>, below).
85		183
86	Example: log something at error level.	184	Example: log something at error level.
87		185
88	AE::log error => "something";	186	AE::log error => "something";
89		187
…		…
97		195
98	=cut	196	=cut
99		197
100	# also allow syslog equivalent names	198	# also allow syslog equivalent names
101	our %STR2LEVEL = (	199	our %STR2LEVEL = (
102	fatal => 1, emerg => 1,	200	fatal => 1, emerg => 1, exit => 1,
103	alert => 2,	201	alert => 2,
104	critical => 3, crit => 3,	202	critical => 3, crit => 3,
105	error => 4, err => 4,	203	error => 4, err => 4, die => 4,
106	warn => 5, warning => 5,	204	warn => 5, warning => 5,
107	note => 6, notice => 6,	205	note => 6, notice => 6,
108	info => 7,	206	info => 7,
109	debug => 8,	207	debug => 8,
110	trace => 9,	208	trace => 9,
111	);	209	);
112		210
		211	sub now () { time }
		212
		213	AnyEvent::post_detect {
		214	*now = \&AE::now;
		215	};
		216
113	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	217	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
114		218
		219	# time, ctx, level, msg
		220	sub _format($$$$) {
		221	my $ts = ft $_[0];
		222	my $ct = " ";
		223
		224	my @res;
		225
		226	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
		227	push @res, "$ts$ct$_\n";
		228	$ct = " + ";
		229	}
		230
		231	join "", @res
		232	}
		233
115	sub _log {	234	sub _log {
116	my ($pkg, $targ, $msg, @args) = @_;	235	my ($ctx, $level, $format, @args) = @_;
117		236
118	my $level = ref $targ ? die "Can't use reference as logging level (yet)"	237	$level = $level > 0 && $level <= 9
119	: $targ > 0 && $targ <= 9 ? $targ+0	238	? $level+0
120	: $STR2LEVEL{$targ} \|\| Carp::croak "$targ: not a valid logging level, caught";	239	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
121		240
122	return if $level > $AnyEvent::VERBOSE;	241	my $mask = 1 << $level;
123		242
124	$msg = $msg->() if ref $msg;	243	my ($success, %seen, @ctx, $now, $fmt);
125	$msg = sprintf $msg, @args if @args;
126	$msg =~ s/\n$//;
127		244
128	# now we have a message, log it	245	do
129	#TODO: could do LOTS of stuff here, and should, at least in some later version	246	{
		247	# skip if masked
		248	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
		249	if ($ctx->[3]) {
		250	# logging target found
130		251
131	$msg = sprintf "%5s %s: %s", $LEVEL2STR[$level], $pkg, $msg;	252	# now get raw message, unless we have it already
132	my $pfx = ft AE::now;	253	unless ($now) {
		254	$format = $format->() if ref $format;
		255	$format = sprintf $format, @args if @args;
		256	$format =~ s/\n$//;
		257	$now = now;
		258	};
133		259
134	for (split /\n/, $msg) {	260	# format msg
135	printf STDERR "$pfx $_\n";	261	my $str = $ctx->[4]
136	$pfx = "\t";	262	? $ctx->[4]($now, $_[0], $level, $format)
137	}	263	: ($fmt \|\|= _format $now, $_[0], $level, $format);
		264
		265	$success = 1;
		266
		267	$ctx->[3]($str)
		268	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		269	} else {
		270	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		271	}
		272	}
		273	}
		274	while $ctx = pop @ctx;
138		275
139	exit 1 if $level <= 1;	276	exit 1 if $level <= 1;
		277
		278	$success
140	}	279	}
141		280
142	sub log($$;@) {	281	sub log($$;@) {
143	_log +(caller)[0], @_;	282	_log
		283	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		284	@_;
144	}	285	}
145		286
146	AnyEvent::log = AE::log = \&log;	287	AnyEvent::log = AE::log = \&log;
147		288
148	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	289	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
149		290
150	Creates a code reference that, when called, acts as if the	291	Creates a code reference that, when called, acts as if the
151	C<AnyEvent::Log::log> function was called at this point with the givne	292	C<AnyEvent::Log::log> function was called at this point with the given
152	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	293	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
153	the C<AnyEvent::Log::log> function:	294	the C<AnyEvent::Log::log> function:
154		295
155	my $debug_log = AnyEvent::Log::logger "debug";	296	my $debug_log = AnyEvent::Log::logger "debug";
156		297
…		…
181	# and later in your program	322	# and later in your program
182	$debug_log->("yo, stuff here") if $debug;	323	$debug_log->("yo, stuff here") if $debug;
183		324
184	$debug and $debug_log->("123");	325	$debug and $debug_log->("123");
185		326
186	Note: currently the enabled var is always true - that will be fixed in a
187	future version :)
188
189	=cut	327	=cut
190		328
191	our %LOGGER;	329	our %LOGGER;
192		330
193	# re-assess logging status for all loggers	331	# re-assess logging status for all loggers
194	sub _reassess {	332	sub _reassess {
		333	local $SIG{__DIE__};
		334	my $die = sub { die };
		335
195	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	336	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
196	my ($pkg, $level, $renabled) = @$_;	337	my ($ctx, $level, $renabled) = @$_;
197		338
198	# to detetc whether a message would be logged, we # actually	339	# to detect whether a message would be logged, we actually
199	# try to log one and die. this isn't # fast, but we can be	340	# try to log one and die. this isn't fast, but we can be
200	# sure that the logging decision is correct :)	341	# sure that the logging decision is correct :)
201		342
202	$$renabled = !eval {	343	$$renabled = !eval {
203	local $SIG{__DIE__};
204
205	_log $pkg, $level, sub { die };	344	_log $ctx, $level, $die;
206		345
207	1	346	1
208	};	347	};
209
210	$$renabled = 1; # TODO
211	}	348	}
212	}	349	}
213		350
214	sub logger($;$) {	351	sub _logger {
215	my ($level, $renabled) = @_;	352	my ($ctx, $level, $renabled) = @_;
216
217	$renabled \|\|= \my $enabled;
218	my $pkg = (caller)[0];
219		353
220	$$renabled = 1;	354	$$renabled = 1;
221		355
222	my $logger = [$pkg, $level, $renabled];	356	my $logger = [$ctx, $level, $renabled];
223		357
224	$LOGGER{$logger+0} = $logger;	358	$LOGGER{$logger+0} = $logger;
225		359
226	_reassess $logger+0;	360	_reassess $logger+0;
227		361
…		…
231	};	365	};
232		366
233	sub {	367	sub {
234	$guard if 0; # keep guard alive, but don't cause runtime overhead	368	$guard if 0; # keep guard alive, but don't cause runtime overhead
235		369
236	_log $pkg, $level, @_	370	_log $ctx, $level, @_
237	if $$renabled;	371	if $$renabled;
238	}	372	}
239	}	373	}
240		374
241	#TODO	375	sub logger($;$) {
		376	_logger
		377	$CTX{ (caller)[0] } \|\|= _pkg_ctx +(caller)[0],
		378	@_
		379	}
242		380
243	=back	381	=back
244		382
245	=head1 CONFIGURATION FUNCTIONALITY	383	=head1 LOGGING CONTEXTS
246		384
247	None, yet, except for C<PERL_ANYEVENT_VERBOSE>, described in the L<AnyEvent> manpage.	385	This module associates every log message with a so-called I<logging
		386	context>, based on the package of the caller. Every perl package has its
		387	own logging context.
		388
		389	A logging context has three major responsibilities: filtering, logging and
		390	propagating the message.
		391
		392	For the first purpose, filtering, each context has a set of logging
		393	levels, called the log level mask. Messages not in the set will be ignored
		394	by this context (masked).
		395
		396	For logging, the context stores a formatting callback (which takes the
		397	timestamp, context, level and string message and formats it in the way
		398	it should be logged) and a logging callback (which is responsible for
		399	actually logging the formatted message and telling C<AnyEvent::Log>
		400	whether it has consumed the message, or whether it should be propagated).
		401
		402	For propagation, a context can have any number of attached I<slave
		403	contexts>. Any message that is neither masked by the logging mask nor
		404	masked by the logging callback returning true will be passed to all slave
		405	contexts.
		406
		407	Each call to a logging function will log the message at most once per
		408	context, so it does not matter (much) if there are cycles or if the
		409	message can arrive at the same context via multiple paths.
		410
		411	=head2 DEFAULTS
		412
		413	By default, all logging contexts have an full set of log levels ("all"), a
		414	disabled logging callback and the default formatting callback.
		415
		416	Package contexts have the package name as logging title by default.
		417
		418	They have exactly one slave - the context of the "parent" package. The
		419	parent package is simply defined to be the package name without the last
		420	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
		421	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		422	exception of the rule - just like the "parent" of any single-component
		423	package name in Perl is C<main>, the default slave of any top-level
		424	package context is C<$AnyEvent::Log::COLLECT>.
		425
		426	Since perl packages form only an approximate hierarchy, this slave
		427	context can of course be removed.
		428
		429	All other (anonymous) contexts have no slaves and an empty title by
		430	default.
		431
		432	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
		433	context that simply logs everything via C<warn>, without propagating
		434	anything anywhere by default. The purpose of this context is to provide
		435	a convenient place to override the global logging target or to attach
		436	additional log targets. It's not meant for filtering.
		437
		438	It then creates the C<$AnyEvent::Log::FILTER> context whose
		439	purpose is to suppress all messages with priority higher
		440	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		441	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		442	is to simply provide filtering according to some global log level.
		443
		444	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		445	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		446	leaves it at default config. Its purpose is simply to collect all log
		447	messages system-wide.
		448
		449	The hierarchy is then:
		450
		451	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		452
		453	The effect of all this is that log messages, by default, wander up to the
		454	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		455	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		456	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		457	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
		458
		459	This makes it easy to set a global logging level (by modifying $FILTER),
		460	but still allow other contexts to send, for example, their debug and trace
		461	messages to the $LOG target despite the global logging level, or to attach
		462	additional log targets that log messages, regardless of the global logging
		463	level.
		464
		465	It also makes it easy to modify the default warn-logger ($LOG) to
		466	something that logs to a file, or to attach additional logging targets
		467	(such as loggign to a file) by attaching it to $FILTER.
		468
		469	=head2 CREATING/FINDING/DESTROYING CONTEXTS
248		470
249	=over 4	471	=over 4
250		472
		473	=item $ctx = AnyEvent::Log::ctx [$pkg]
		474
		475	This function creates or returns a logging context (which is an object).
		476
		477	If a package name is given, then the context for that packlage is
		478	returned. If it is called without any arguments, then the context for the
		479	callers package is returned (i.e. the same context as a C<AE::log> call
		480	would use).
		481
		482	If C<undef> is given, then it creates a new anonymous context that is not
		483	tied to any package and is destroyed when no longer referenced.
		484
251	=cut	485	=cut
		486
		487	sub ctx(;$) {
		488	my $pkg = @_ ? shift : (caller)[0];
		489
		490	ref $pkg
		491	? $pkg
		492	: defined $pkg
		493	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
		494	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
		495	}
		496
		497	=item AnyEvent::Log::reset
		498
		499	Resets all package contexts and recreates the default hierarchy if
		500	necessary, i.e. resets the logging subsystem to defaults, as much as
		501	possible. This process keeps references to contexts held by other parts of
		502	the program intact.
		503
		504	This can be used to implement config-file (re-)loading: before loading a
		505	configuration, reset all contexts.
		506
		507	=cut
		508
		509	sub reset {
		510	# hard to kill complex data structures
		511	# we "recreate" all package loggers and reset the hierarchy
		512	while (my ($k, $v) = each %CTX) {
		513	@$v = ($k, (1 << 10) - 1 - 1, { });
		514
		515	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
		516	}
		517
		518	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		519	for $LOG, $FILTER, $COLLECT;
		520
		521	#$LOG->slaves;
		522	$LOG->title ('$AnyEvent::Log::LOG');
		523	$LOG->log_to_warn;
		524
		525	$FILTER->slaves ($LOG);
		526	$FILTER->title ('$AnyEvent::Log::FILTER');
		527	$FILTER->level ($AnyEvent::VERBOSE);
		528
		529	$COLLECT->slaves ($FILTER);
		530	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		531
		532	_reassess;
		533	}
		534
		535	# create the default logger contexts
		536	$LOG = ctx undef;
		537	$FILTER = ctx undef;
		538	$COLLECT = ctx undef;
		539
		540	AnyEvent::Log::reset;
		541
		542	# hello, CPAN, please catch me
		543	package AnyEvent::Log::LOG;
		544	package AE::Log::LOG;
		545	package AnyEvent::Log::FILTER;
		546	package AE::Log::FILTER;
		547	package AnyEvent::Log::COLLECT;
		548	package AE::Log::COLLECT;
		549
		550	package AnyEvent::Log::Ctx;
		551
		552	# 0 1 2 3 4
		553	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		554
		555	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		556
		557	This is a convenience constructor that makes it simpler to construct
		558	anonymous logging contexts.
		559
		560	Each key-value pair results in an invocation of the method of the same
		561	name as the key with the value as parameter, unless the value is an
		562	arrayref, in which case it calls the method with the contents of the
		563	array. The methods are called in the same order as specified.
		564
		565	Example: create a new logging context and set both the default logging
		566	level, some slave contexts and a logging callback.
		567
		568	$ctx = new AnyEvent::Log::Ctx
		569	title => "dubious messages",
		570	level => "error",
		571	log_cb => sub { print STDOUT shift; 0 },
		572	slaves => [$ctx1, $ctx, $ctx2],
		573	;
		574
		575	=back
		576
		577	=cut
		578
		579	sub new {
		580	my $class = shift;
		581
		582	my $ctx = AnyEvent::Log::ctx undef;
		583
		584	while (@_) {
		585	my ($k, $v) = splice @_, 0, 2;
		586	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		587	}
		588
		589	bless $ctx, $class # do we really support subclassing, hmm?
		590	}
		591
		592
		593	=head2 CONFIGURING A LOG CONTEXT
		594
		595	The following methods can be used to configure the logging context.
		596
		597	=over 4
		598
		599	=item $ctx->title ([$new_title])
		600
		601	Returns the title of the logging context - this is the package name, for
		602	package contexts, and a user defined string for all others.
		603
		604	If C<$new_title> is given, then it replaces the package name or title.
		605
		606	=cut
		607
		608	sub title {
		609	$_[0][0] = $_[1] if @_ > 1;
		610	$_[0][0]
		611	}
		612
		613	=back
		614
		615	=head3 LOGGING LEVELS
		616
		617	The following methods deal with the logging level set associated with the
		618	log context.
		619
		620	The most common method to use is probably C<< $ctx->level ($level) >>,
		621	which configures the specified and any higher priority levels.
		622
		623	All functions which accept a list of levels also accept the special string
		624	C<all> which expands to all logging levels.
		625
		626	=over 4
		627
		628	=item $ctx->levels ($level[, $level...)
		629
		630	Enables logging for the given levels and disables it for all others.
		631
		632	=item $ctx->level ($level)
		633
		634	Enables logging for the given level and all lower level (higher priority)
		635	ones. In addition to normal logging levels, specifying a level of C<0> or
		636	C<off> disables all logging for this level.
		637
		638	Example: log warnings, errors and higher priority messages.
		639
		640	$ctx->level ("warn");
		641	$ctx->level (5); # same thing, just numeric
		642
		643	=item $ctx->enable ($level[, $level...])
		644
		645	Enables logging for the given levels, leaving all others unchanged.
		646
		647	=item $ctx->disable ($level[, $level...])
		648
		649	Disables logging for the given levels, leaving all others unchanged.
		650
		651	=cut
		652
		653	sub _lvl_lst {
		654	map {
		655	$_ > 0 && $_ <= 9 ? $_+0
		656	: $_ eq "all" ? (1 .. 9)
		657	: $STR2LEVEL{$_} \|\| Carp::croak "$_: not a valid logging level, caught"
		658	} @_
		659	}
		660
		661	our $NOP_CB = sub { 0 };
		662
		663	sub levels {
		664	my $ctx = shift;
		665	$ctx->[1] = 0;
		666	$ctx->[1] \|= 1 << $_
		667	for &_lvl_lst;
		668	AnyEvent::Log::_reassess;
		669	}
		670
		671	sub level {
		672	my $ctx = shift;
		673	my $lvl = $_[0] =~ /^(?:0\|off\|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
		674
		675	$ctx->[1] = ((1 << $lvl) - 1) << 1;
		676	AnyEvent::Log::_reassess;
		677	}
		678
		679	sub enable {
		680	my $ctx = shift;
		681	$ctx->[1] \|= 1 << $_
		682	for &_lvl_lst;
		683	AnyEvent::Log::_reassess;
		684	}
		685
		686	sub disable {
		687	my $ctx = shift;
		688	$ctx->[1] &= ~(1 << $_)
		689	for &_lvl_lst;
		690	AnyEvent::Log::_reassess;
		691	}
		692
		693	=back
		694
		695	=head3 SLAVE CONTEXTS
		696
		697	The following methods attach and detach another logging context to a
		698	logging context.
		699
		700	Log messages are propagated to all slave contexts, unless the logging
		701	callback consumes the message.
		702
		703	=over 4
		704
		705	=item $ctx->attach ($ctx2[, $ctx3...])
		706
		707	Attaches the given contexts as slaves to this context. It is not an error
		708	to add a context twice (the second add will be ignored).
		709
		710	A context can be specified either as package name or as a context object.
		711
		712	=item $ctx->detach ($ctx2[, $ctx3...])
		713
		714	Removes the given slaves from this context - it's not an error to attempt
		715	to remove a context that hasn't been added.
		716
		717	A context can be specified either as package name or as a context object.
		718
		719	=item $ctx->slaves ($ctx2[, $ctx3...])
		720
		721	Replaces all slaves attached to this context by the ones given.
		722
		723	=cut
		724
		725	sub attach {
		726	my $ctx = shift;
		727
		728	$ctx->[2]{$_+0} = $_
		729	for map { AnyEvent::Log::ctx $_ } @_;
		730	}
		731
		732	sub detach {
		733	my $ctx = shift;
		734
		735	delete $ctx->[2]{$_+0}
		736	for map { AnyEvent::Log::ctx $_ } @_;
		737	}
		738
		739	sub slaves {
		740	undef $_[0][2];
		741	&attach;
		742	}
		743
		744	=back
		745
		746	=head3 LOG TARGETS
		747
		748	The following methods configure how the logging context actually does
		749	the logging (which consists of formatting the message and printing it or
		750	whatever it wants to do with it).
		751
		752	=over 4
		753
		754	=item $ctx->log_cb ($cb->($str)
		755
		756	Replaces the logging callback on the context (C<undef> disables the
		757	logging callback).
		758
		759	The logging callback is responsible for handling formatted log messages
		760	(see C<fmt_cb> below) - normally simple text strings that end with a
		761	newline (and are possibly multiline themselves).
		762
		763	It also has to return true iff it has consumed the log message, and false
		764	if it hasn't. Consuming a message means that it will not be sent to any
		765	slave context. When in doubt, return C<0> from your logging callback.
		766
		767	Example: a very simple logging callback, simply dump the message to STDOUT
		768	and do not consume it.
		769
		770	$ctx->log_cb (sub { print STDERR shift; 0 });
		771
		772	You can filter messages by having a log callback that simply returns C<1>
		773	and does not do anything with the message, but this counts as "message
		774	being logged" and might not be very efficient.
		775
		776	Example: propagate all messages except for log levels "debug" and
		777	"trace". The messages will still be generated, though, which can slow down
		778	your program.
		779
		780	$ctx->levels ("debug", "trace");
		781	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
		782
		783	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
		784
		785	Replaces the formatting callback on the context (C<undef> restores the
		786	default formatter).
		787
		788	The callback is passed the (possibly fractional) timestamp, the original
		789	logging context, the (numeric) logging level and the raw message string
		790	and needs to return a formatted log message. In most cases this will be a
		791	string, but it could just as well be an array reference that just stores
		792	the values.
		793
		794	If, for some reason, you want to use C<caller> to find out more baout the
		795	logger then you should walk up the call stack until you are no longer
		796	inside the C<AnyEvent::Log> package.
		797
		798	Example: format just the raw message, with numeric log level in angle
		799	brackets.
		800
		801	$ctx->fmt_cb (sub {
		802	my ($time, $ctx, $lvl, $msg) = @_;
		803
		804	"<$lvl>$msg\n"
		805	});
		806
		807	Example: return an array reference with just the log values, and use
		808	C<PApp::SQL::sql_exec> to store the emssage in a database.
		809
		810	$ctx->fmt_cb (sub { \@_ });
		811	$ctx->log_cb (sub {
		812	my ($msg) = @_;
		813
		814	sql_exec "insert into log (when, subsys, prio, msg) values (?, ?, ?, ?)",
		815	$msg->[0] + 0,
		816	"$msg->[1]",
		817	$msg->[2] + 0,
		818	"$msg->[3]";
		819
		820	0
		821	});
		822
		823	=item $ctx->log_to_warn
		824
		825	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		826	(usually this logs to STDERR).
		827
		828	=item $ctx->log_to_file ($path)
		829
		830	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		831
		832	=item $ctx->log_to_path ($path)
		833
		834	Same as C<< ->log_to_file >>, but opens the file for each message. This
		835	is much slower, but allows you to change/move/rename/delete the file at
		836	basically any time.
		837
		838	Needless(?) to say, if you do not want to be bitten by some evil person
		839	calling C<chdir>, the path should be absolute. Doesn't help with
		840	C<chroot>, but hey...
		841
		842	=item $ctx->log_to_syslog ([$log_flags])
		843
		844	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
		845	the others in the obvious way. If specified, then the C<$log_flags> are
		846	simply or'ed onto the priority argument and can contain any C<LOG_xxx>
		847	flags valid for Sys::Syslog::syslog, except for the priority levels.
		848
		849	Note that this function also sets a C<fmt_cb> - the logging part requires
		850	an array reference with [$level, $str] as input.
		851
		852	=cut
		853
		854	sub log_cb {
		855	my ($ctx, $cb) = @_;
		856
		857	$ctx->[3] = $cb;
		858	}
		859
		860	sub fmt_cb {
		861	my ($ctx, $cb) = @_;
		862
		863	$ctx->[4] = $cb;
		864	}
		865
		866	sub log_to_warn {
		867	my ($ctx, $path) = @_;
		868
		869	$ctx->log_cb (sub {
		870	warn shift;
		871	0
		872	});
		873	}
		874
		875	sub log_to_file {
		876	my ($ctx, $path) = @_;
		877
		878	open my $fh, ">>", $path
		879	or die "$path: $!";
		880
		881	$ctx->log_cb (sub {
		882	syswrite $fh, shift;
		883	0
		884	});
		885	}
		886
		887	sub log_to_path {
		888	my ($ctx, $path) = @_;
		889
		890	$ctx->log_cb (sub {
		891	open my $fh, ">>", $path
		892	or die "$path: $!";
		893
		894	syswrite $fh, shift;
		895	0
		896	});
		897	}
		898
		899	sub log_to_syslog {
		900	my ($ctx, $flags) = @_;
		901
		902	require Sys::Syslog;
		903
		904	$ctx->fmt_cb (sub {
		905	my $str = $_[3];
		906	$str =~ s/\n(?=.)/\n+ /g;
		907
		908	[$_[2], "($_[1][0]) $str"]
		909	});
		910
		911	$ctx->log_cb (sub {
		912	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		913
		914	Sys::Syslog::syslog ($flags \| ($lvl - 1), $_)
		915	for split /\n/, $_[0][1];
		916
		917	0
		918	});
		919	}
		920
		921	=back
		922
		923	=head3 MESSAGE LOGGING
		924
		925	These methods allow you to log messages directly to a context, without
		926	going via your package context.
		927
		928	=over 4
		929
		930	=item $ctx->log ($level, $msg[, @params])
		931
		932	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		933
		934	=item $logger = $ctx->logger ($level[, \$enabled])
		935
		936	Same as C<AnyEvent::Log::logger>, but uses the given context as log
		937	context.
		938
		939	=cut
		940
		941	*log = \&AnyEvent::Log::_log;
		942	*logger = \&AnyEvent::Log::_logger;
		943
		944	=back
		945
		946	=cut
		947
		948	package AnyEvent::Log;
		949
		950	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		951
		952	Logging can also be configured by setting the environment variable
		953	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		954
		955	The value consists of one or more logging context specifications separated
		956	by C<:> or whitespace. Each logging specification in turn starts with a
		957	context name, followed by C<=>, followed by zero or more comma-separated
		958	configuration directives, here are some examples:
		959
		960	# set default logging level
		961	filter=warn
		962
		963	# log to file instead of to stderr
		964	log=file=/tmp/mylog
		965
		966	# log to file in addition to stderr
		967	log=+%file:%file=file=/tmp/mylog
		968
		969	# enable debug log messages, log warnings and above to syslog
		970	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		971
		972	# log trace messages (only) from AnyEvent::Debug to file
		973	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		974
		975	A context name in the log specification can be any of the following:
		976
		977	=over 4
		978
		979	=item C<collect>, C<filter>, C<log>
		980
		981	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		982	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		983
		984	=item C<%name>
		985
		986	Context names starting with a C<%> are anonymous contexts created when the
		987	name is first mentioned. The difference to package contexts is that by
		988	default they have no attached slaves.
		989
		990	=item a perl package name
		991
		992	Any other string references the logging context associated with the given
		993	Perl C<package>. In the unlikely case where you want to specify a package
		994	context that matches on of the other context name forms, you can add a
		995	C<::> to the package name to force interpretation as a package.
		996
		997	=back
		998
		999	The configuration specifications can be any number of the following:
		1000
		1001	=over 4
		1002
		1003	=item C<stderr>
		1004
		1005	Configures the context to use Perl's C<warn> function (which typically
		1006	logs to C<STDERR>). Works like C<log_to_warn>.
		1007
		1008	=item C<file=>I<path>
		1009
		1010	Configures the context to log to a file with the given path. Works like
		1011	C<log_to_file>.
		1012
		1013	=item C<path=>I<path>
		1014
		1015	Configures the context to log to a file with the given path. Works like
		1016	C<log_to_path>.
		1017
		1018	=item C<syslog> or C<syslog=>I<expr>
		1019
		1020	Configures the context to log to syslog. If I<expr> is given, then it is
		1021	evaluated in the L<Sys::Syslog> package, so you could use:
		1022
		1023	log=syslog=LOG_LOCAL0
		1024
		1025	=item C<nolog>
		1026
		1027	Configures the context to not log anything by itself, which is the
		1028	default. Same as C<< $ctx->log_cb (undef) >>.
		1029
		1030	=item C<0> or C<off>
		1031
		1032	Sets the logging level of the context ot C<0>, i.e. all messages will be
		1033	filtered out.
		1034
		1035	=item C<all>
		1036
		1037	Enables all logging levels, i.e. filtering will effectively be switched
		1038	off (the default).
		1039
		1040	=item C<only>
		1041
		1042	Disables all logging levels, and changes the interpretation of following
		1043	level specifications to enable the specified level only.
		1044
		1045	Example: only enable debug messages for a context.
		1046
		1047	context=only,debug
		1048
		1049	=item C<except>
		1050
		1051	Enables all logging levels, and changes the interpretation of following
		1052	level specifications to disable that level. Rarely used.
		1053
		1054	Example: enable all logging levels except fatal and trace (this is rather
		1055	nonsensical).
		1056
		1057	filter=exept,fatal,trace
		1058
		1059	=item C<level>
		1060
		1061	Enables all logging levels, and changes the interpretation of following
		1062	level specifications to be "that level or any higher priority
		1063	message". This is the default.
		1064
		1065	Example: log anything at or above warn level.
		1066
		1067	filter=warn
		1068
		1069	# or, more verbose
		1070	filter=only,level,warn
		1071
		1072	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1073
		1074	A numeric loglevel or the name of a loglevel will be interpreted according
		1075	to the most recent C<only>, C<except> or C<level> directive. By default,
		1076	specifying a logging level enables that and any higher priority messages.
		1077
		1078	=item C<+>I<context>
		1079
		1080	Attaches the named context as slave to the context.
		1081
		1082	=item C<+>
		1083
		1084	A line C<+> detaches all contexts, i.e. clears the slave list from the
		1085	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1086	but package contexts have the parent context as slave by default.
		1087
		1088	Example: log messages from My::Module to a file, do not send them to the
		1089	default log collector.
		1090
		1091	My::Module=+,file=/tmp/mymodulelog
		1092
		1093	=back
		1094
		1095	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1096	usual, so to log to a file containing a comma, colon, backslash and some
		1097	spaces in the filename, you would do this:
		1098
		1099	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1100
		1101	Since whitespace (which includes newlines) is allowed, it is fine to
		1102	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1103
		1104	PERL_ANYEVENT_LOG="
		1105	filter=warn
		1106	AnyEvent::Debug=+%trace
		1107	%trace=only,trace,+log
		1108	" myprog
		1109
		1110	Also, in the unlikely case when you want to concatenate specifications,
		1111	use whitespace as separator, as C<::> will be interpreted as part of a
		1112	module name, an empty spec with two separators:
		1113
		1114	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1115
		1116	=cut
		1117
		1118	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1119	my %anon;
		1120
		1121	my $pkg = sub {
		1122	$_[0] eq "log" ? $LOG
		1123	: $_[0] eq "filter" ? $FILTER
		1124	: $_[0] eq "collect" ? $COLLECT
		1125	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} \|\|= ctx undef)
		1126	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1127	: die # never reached?
		1128	};
		1129
		1130	/\G[[:space:]]+/gc; # skip initial whitespace
		1131
		1132	while (/\G((?:[^:=[:space:]]+\|::\|\\.)+)=/gc) {
		1133	my $ctx = $pkg->($1);
		1134	my $level = "level";
		1135
		1136	while (/\G((?:[^,:[:space:]]+\|::\|\\.)+)/gc) {
		1137	for ("$1") {
		1138	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1139	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1140	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1141	} elsif (/syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog (eval "package Sys::Syslog; $1");
		1142	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1143	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1144	} elsif ($_ eq "+" ) { $ctx->slaves;
		1145	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1146	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1147	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1148	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1149	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1150	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1151	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1152	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1153	}
		1154	}
		1155
		1156	/\G,/gc or last;
		1157	}
		1158
		1159	/\G[:[:space:]]+/gc or last;
		1160	}
		1161
		1162	/\G[[:space:]]+/gc; # skip trailing whitespace
		1163
		1164	if (/\G(.+)/g) {
		1165	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1166	}
		1167	}
252		1168
253	1;	1169	1;
		1170
		1171	=head1 EXAMPLES
		1172
		1173	This section shows some common configurations, both as code, and as
		1174	C<PERL_ANYEVENT_LOG> string.
		1175
		1176	=over 4
		1177
		1178	=item Setting the global logging level.
		1179
		1180	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
		1181	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1182	the root context at runtime:
		1183
		1184	PERL_ANYEVENT_VERBOSE=5 ./myprog
		1185
		1186	PERL_ANYEVENT_LOG=log=warn
		1187
		1188	$AnyEvent::Log::FILTER->level ("warn");
		1189
		1190	=item Append all messages to a file instead of sending them to STDERR.
		1191
		1192	This is affected by the global logging level.
		1193
		1194	$AnyEvent::Log::LOG->log_to_file ($path);
		1195
		1196	PERL_ANYEVENT_LOG=log=file=/some/path
		1197
		1198	=item Write all messages with priority C<error> and higher to a file.
		1199
		1200	This writes them only when the global logging level allows it, because
		1201	it is attached to the default context which is invoked I<after> global
		1202	filtering.
		1203
		1204	$AnyEvent::Log::FILTER->attach
		1205	new AnyEvent::Log::Ctx log_to_file => $path);
		1206
		1207	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
		1208
		1209	This writes them regardless of the global logging level, because it is
		1210	attached to the toplevel context, which receives all messages I<before>
		1211	the global filtering.
		1212
		1213	$AnyEvent::Log::COLLECT->attach (
		1214	new AnyEvent::Log::Ctx log_to_file => $path);
		1215
		1216	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1217
		1218	In both cases, messages are still written to STDERR.
		1219
		1220	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		1221
		1222	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		1223	context - this simply circumvents the global filtering for trace messages.
		1224
		1225	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		1226	$debug->attach ($AnyEvent::Log::LOG);
		1227
		1228	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1229
		1230	This of course works for any package, not just L<AnyEvent::Debug>, but
		1231	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1232	default.
254		1233
255	=back	1234	=back
256		1235
257	=head1 AUTHOR	1236	=head1 AUTHOR
258		1237
259	Marc Lehmann <schmorp@schmorp.de>	1238	Marc Lehmann <schmorp@schmorp.de>
260	http://home.schmorp.de/	1239	http://home.schmorp.de/
261		1240
262	=cut	1241	=cut
		1242

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs. Revision 1.36 by root, Thu Aug 25 05:39:47 2011 UTC

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.3 by root, Wed Aug 17 02:02:38 2011 UTC vs.
Revision 1.36 by root, Thu Aug 25 05:39:47 2011 UTC