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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.15 by root, Sat Aug 20 02:16:59 2011 UTC vs.
Revision 1.62 by root, Sat Sep 28 11:12:56 2013 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 use	7	Simple uses:
		8
8	use AnyEvent;	9	use AnyEvent;
9		10
10	AE::log debug => "hit my knee";	11	AE::log fatal => "No config found, cannot continue!"; # never returns
11	AE::log warn => "it's a bit too hot";	12	AE::log alert => "The battery died!";
12	AE::log error => "the flag was false!";	13	AE::log crit => "The battery temperature is too hot!";
13	AE::log fatal => "the bit toggled! run!";	14	AE::log error => "Division by zero attempted.";
		15	AE::log warn => "Couldn't delete the file.";
		16	AE::log note => "Wanted to create config, but config already exists.";
		17	AE::log info => "File soandso successfully deleted.";
		18	AE::log debug => "the function returned 3";
		19	AE::log trace => "going to call function abc";
14		20
15	# "complex" use	21	Log level overview:
		22
		23	LVL NAME SYSLOG PERL NOTE
		24	1 fatal emerg exit system unusable, aborts program!
		25	2 alert failure in primary system
		26	3 critical crit failure in backup system
		27	4 error err die non-urgent program errors, a bug
		28	5 warn warning possible problem, not necessarily error
		29	6 note notice unusual conditions
		30	7 info normal messages, no action required
		31	8 debug debugging messages for development
		32	9 trace copious tracing output
		33
		34	"Complex" uses (for speed sensitive code, e.g. trace/debug messages):
		35
16	use AnyEvent::Log;	36	use AnyEvent::Log;
17		37
18	my $tracer = AnyEvent::Log::logger trace => \$my $trace;	38	my $tracer = AnyEvent::Log::logger trace => \$my $trace;
19		39
20	$tracer->("i am here") if $trace;	40	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	41	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		42
23	# configuration	43	Configuration (also look at the EXAMPLES section):
24		44
25	# set logging for this package to maximum	45	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("all");	46	AnyEvent::Log::ctx->level ("error");
27		47
28	# set logging globally to anything below debug	48	# set logging level to suppress anything below "notice"
29	(AnyEvent::Log::ctx "")->level ("notice");	49	$AnyEvent::Log::FILTER->level ("notice");
30		50
31	# see also EXAMPLES, below	51	# send all critical and higher priority messages to syslog,
32		52	# regardless of (most) other settings
33	# disable logging for package "AnyEvent" and all packages below it	53	$AnyEvent::Log::COLLECT->attach (new AnyEvent::Log::Ctx
34	AnyEvent->AnyEvent::Log::ctx->level (0);	54	level => "critical",
35		55	log_to_syslog => "user",
36	# log everything below debug to a file, for the whole program	56	);
37	my $ctx = AnyEvent::Log::ctx;
38	$ctx->log_cb (sub { print FILE shift; 0 });
39	(AnyEvent::Log::ctx "")->add ($ctx);
40		57
41	=head1 DESCRIPTION	58	=head1 DESCRIPTION
42		59
43	This module implements a relatively simple "logging framework". It doesn't	60	This module implements a relatively simple "logging framework". It doesn't
44	attempt to be "the" logging solution or even "a" logging solution for	61	attempt to be "the" logging solution or even "a" logging solution for
45	AnyEvent - AnyEvent simply creates logging messages internally, and this	62	AnyEvent - AnyEvent simply creates logging messages internally, and this
46	module more or less exposes the mechanism, with some extra spiff to allow	63	module more or less exposes the mechanism, with some extra spiff to allow
47	using it from other modules as well.	64	using it from other modules as well.
48		65
49	Remember that the default verbosity level is C<0>, so nothing will be	66	Remember that the default verbosity level is C<4> (C<error>), so only
50	logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number before	67	errors and more important messages will be logged, unless you set
51	starting your program, or change the logging level at runtime with	68	C<PERL_ANYEVENT_VERBOSE> to a higher number before starting your program
52	something like:	69	(C<AE_VERBOSE=5> is recommended during development), or change the logging
		70	level at runtime with something like:
53		71
54	use AnyEvent;	72	use AnyEvent::Log;
55	(AnyEvent::Log::ctx "")->level ("info");	73	$AnyEvent::Log::FILTER->level ("info");
56		74
57	The design goal behind this module was to keep it simple (and small),	75	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	76	but make it powerful enough to be potentially useful for any module,
59	extensive enough for the most common tasks, such as logging to multiple	77	and extensive enough for the most common tasks, such as logging to
60	targets, or being able to log into a database.	78	multiple targets, or being able to log into a database.
61		79
		80	The module is also usable before AnyEvent itself is initialised, in which
		81	case some of the functionality might be reduced.
		82
62	The amount of documentation might indicate otherwise, but the module is	83	The amount of documentation might indicate otherwise, but the runtime part
63	still just 240 lines or so.	84	of the module is still just below 300 lines of code.
		85
		86	=head1 LOGGING LEVELS
		87
		88	Logging levels in this module range from C<1> (highest priority) to C<9>
		89	(lowest priority). Note that the lowest numerical value is the highest
		90	priority, so when this document says "higher priority" it means "lower
		91	numerical value".
		92
		93	Instead of specifying levels by name you can also specify them by aliases:
		94
		95	LVL NAME SYSLOG PERL NOTE
		96	1 fatal emerg exit system unusable, aborts program!
		97	2 alert failure in primary system
		98	3 critical crit failure in backup system
		99	4 error err die non-urgent program errors, a bug
		100	5 warn warning possible problem, not necessarily error
		101	6 note notice unusual conditions
		102	7 info normal messages, no action required
		103	8 debug debugging messages for development
		104	9 trace copious tracing output
		105
		106	As you can see, some logging levels have multiple aliases - the first one
		107	is the "official" name, the second one the "syslog" name (if it differs)
		108	and the third one the "perl" name, suggesting (only!) that you log C<die>
		109	messages at C<error> priority. The NOTE column tries to provide some
		110	rationale on how to chose a logging level.
		111
		112	As a rough guideline, levels 1..3 are primarily meant for users of the
		113	program (admins, staff), and are the only ones logged to STDERR by
		114	default. Levels 4..6 are meant for users and developers alike, while
		115	levels 7..9 are usually meant for developers.
		116
		117	You can normally only log a message once at highest priority level (C<1>,
		118	C<fatal>), because logging a fatal message will also quit the program - so
		119	use it sparingly :)
		120
		121	For example, a program that finds an unknown switch on the commandline
		122	might well use a fatal logging level to tell users about it - the "system"
		123	in this case would be the program, or module.
		124
		125	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		126	or C<all> - these are only valid for the methods that documented them.
64		127
65	=head1 LOGGING FUNCTIONS	128	=head1 LOGGING FUNCTIONS
66		129
67	These functions allow you to log messages. They always use the caller's	130	The following functions allow you to log messages. They always use the
68	package as a "logging module/source". Also, the main logging function is	131	caller's package as a "logging context". Also, the main logging function,
69	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	132	C<log>, is aliased to C<AnyEvent::log> and C<AE::log> when the C<AnyEvent>
70	loaded.	133	module is loaded.
71		134
72	=over 4	135	=over 4
73		136
74	=cut	137	=cut
75		138
76	package AnyEvent::Log;	139	package AnyEvent::Log;
77		140
78	use Carp ();	141	use Carp ();
79	use POSIX ();	142	use POSIX ();
80		143
		144	# layout of a context
		145	# 0 1 2 3 4, 5
		146	# [$title, $level, %$slaves, &$logcb, &$fmtcb, $cap]
		147
81	use AnyEvent (); BEGIN { AnyEvent::common_sense }	148	use AnyEvent (); BEGIN { AnyEvent::common_sense }
82	use AnyEvent::Util ();	149	#use AnyEvent::Util (); need to load this in a delayed fashion, as it uses AE::log
83		150
84	our $VERSION = $AnyEvent::VERSION;	151	our $VERSION = $AnyEvent::VERSION;
85		152
		153	our ($COLLECT, $FILTER, $LOG);
		154
86	our ($now_int, $now_str1, $now_str2);	155	our ($now_int, $now_str1, $now_str2);
87		156
88	# Format Time, not public - yet?	157	# Format Time, not public - yet?
89	sub ft($) {	158	sub format_time($) {
90	my $i = int $_[0];	159	my $i = int $_[0];
91	my $f = sprintf "%06d", 1e6 * ($_[0] - $i);	160	my $f = sprintf "%06d", 1e6 * ($_[0] - $i);
92		161
93	($now_int, $now_str1, $now_str2) = ($i, split /\x01/, POSIX::strftime "%Y-%m-%d %H:%M:%S.\x01 %z", localtime $i)	162	($now_int, $now_str1, $now_str2) = ($i, split /\x01/, POSIX::strftime "%Y-%m-%d %H:%M:%S.\x01 %z", localtime $i)
94	if $now_int != $i;	163	if $now_int != $i;
95		164
96	"$now_str1$f$now_str2"	165	"$now_str1$f$now_str2"
97	}	166	}
98		167
99	our %CTX; # all logging contexts	168	our %CTX; # all package contexts
100		169
101	# creates a default package context object for the given package	170	# creates a default package context object for the given package
102	sub _pkg_ctx($) {	171	sub _pkg_ctx($) {
103	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	172	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
104		173
105	# link "parent" package	174	# link "parent" package
106	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "AE::Log::Top";	175	my $parent = $_[0] =~ /^(.+)::/
		176	? $CTX{$1} ||= &_pkg_ctx ("$1")
		177	: $COLLECT;
107		178
108	$pkg = $CTX{$pkg} ||= &_pkg_ctx ($pkg);
109	$ctx->[2]{$pkg+0} = $pkg;	179	$ctx->[2]{$parent+0} = $parent;
110		180
111	$ctx	181	$ctx
112	}	182	}
113		183
114	=item AnyEvent::Log::log $level, $msg[, @args]	184	=item AnyEvent::Log::log $level, $msg[, @args]
115		185
116	Requests logging of the given C<$msg> with the given log level (1..9).	186	Requests logging of the given C<$msg> with the given log level, and
117	You can also use the following strings as log level: C<fatal> (1),	187	returns true if the message was logged I<somewhere>.
118	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
119	C<info> (7), C<debug> (8), C<trace> (9).
120		188
121	For C<fatal> log levels, the program will abort.	189	For loglevel C<fatal>, the program will abort.
122		190
123	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	191	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
124	C<$msg> is interpreted as an sprintf format string.	192	C<$msg> is interpreted as an sprintf format string.
125		193
126	The C<$msg> should not end with C<\n>, but may if that is convenient for	194	The C<$msg> should not end with C<\n>, but may if that is convenient for
…		…
129	Last not least, C<$msg> might be a code reference, in which case it is	197	Last not least, C<$msg> might be a code reference, in which case it is
130	supposed to return the message. It will be called only then the message	198	supposed to return the message. It will be called only then the message
131	actually gets logged, which is useful if it is costly to create the	199	actually gets logged, which is useful if it is costly to create the
132	message in the first place.	200	message in the first place.
133		201
		202	This function takes care of saving and restoring C<$!> and C<$@>, so you
		203	don't have to.
		204
134	Whether the given message will be logged depends on the maximum log level	205	Whether the given message will be logged depends on the maximum log level
135	and the caller's package.	206	and the caller's package. The return value can be used to ensure that
		207	messages or not "lost" - for example, when L<AnyEvent::Debug> detects a
		208	runtime error it tries to log it at C<die> level, but if that message is
		209	lost it simply uses warn.
136		210
137	Note that you can (and should) call this function as C<AnyEvent::log> or	211	Note that you can (and should) call this function as C<AnyEvent::log> or
138	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	212	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
139	need any additional functionality), as those functions will load the	213	need any additional functionality), as those functions will load the
140	logging module on demand only. They are also much shorter to write.	214	logging module on demand only. They are also much shorter to write.
…		…
157		231
158	=cut	232	=cut
159		233
160	# also allow syslog equivalent names	234	# also allow syslog equivalent names
161	our %STR2LEVEL = (	235	our %STR2LEVEL = (
162	fatal => 1, emerg => 1,	236	fatal => 1, emerg => 1, exit => 1,
163	alert => 2,	237	alert => 2,
164	critical => 3, crit => 3,	238	critical => 3, crit => 3,
165	error => 4, err => 4,	239	error => 4, err => 4, die => 4,
166	warn => 5, warning => 5,	240	warn => 5, warning => 5,
167	note => 6, notice => 6,	241	note => 6, notice => 6,
168	info => 7,	242	info => 7,
169	debug => 8,	243	debug => 8,
170	trace => 9,	244	trace => 9,
171	);	245	);
172		246
173	sub now () { time }	247	our $TIME_EXACT;
		248
		249	sub exact_time($) {
		250	$TIME_EXACT = shift;
		251	*_ts = $AnyEvent::MODEL
		252	? $TIME_EXACT ? \&AE::now : \&AE::time
		253	: sub () { $TIME_EXACT ? do { require Time::HiRes; Time::HiRes::time () } : time };
		254	}
		255
		256	BEGIN {
		257	exact_time 0;
		258	}
174		259
175	AnyEvent::post_detect {	260	AnyEvent::post_detect {
176	*now = \&AE::now;	261	exact_time $TIME_EXACT;
177	};	262	};
178		263
179	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	264	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
180		265
181	# time, ctx, level, msg	266	# time, ctx, level, msg
182	sub _format($$$$) {	267	sub default_format($$$$) {
183	my $ts = ft $_[0];	268	my $ts = format_time $_[0];
184	my $ct = " ";	269	my $ct = " ";
185		270
186	my @res;	271	my @res;
187		272
188	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {	273	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
…		…
191	}	276	}
192		277
193	join "", @res	278	join "", @res
194	}	279	}
195		280
		281	sub fatal_exit() {
		282	exit 1;
		283	}
		284
196	sub _log {	285	sub _log {
197	my ($ctx, $level, $format, @args) = @_;	286	my ($ctx, $level, $format, @args) = @_;
198		287
199	$level = $level > 0 && $level <= 9	288	$level = $level > 0 && $level <= 9
200	? $level+0	289	? $level+0
201	: $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";	290	: $STR2LEVEL{$level} || Carp::croak "$level: not a valid logging level, caught";
202		291
203	my $mask = 1 << $level;	292	my $mask = 1 << $level;
204		293
205	my (%seen, @ctx, $now, $fmt);	294	my ($success, %seen, @ctx, $now, @fmt);
206		295
207	do	296	do
208	{	297	{
209	# skip if masked	298	# if !ref, then it's a level number
		299	if (!ref $ctx) {
		300	$level = $ctx;
210	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {	301	} elsif ($ctx->[1] & $mask and !$seen{$ctx+0}++) {
		302	# logging/recursing into this context
		303
		304	# level cap
		305	if ($ctx->[5] > $level) {
		306	push @ctx, $level; # restore level when going up in tree
		307	$level = $ctx->[5];
		308	}
		309
		310	# log if log cb
211	if ($ctx->[3]) {	311	if ($ctx->[3]) {
212	# logging target found	312	# logging target found
		313
		314	local ($!, $@);
213		315
214	# now get raw message, unless we have it already	316	# now get raw message, unless we have it already
215	unless ($now) {	317	unless ($now) {
216	$format = $format->() if ref $format;	318	$format = $format->() if ref $format;
217	$format = sprintf $format, @args if @args;	319	$format = sprintf $format, @args if @args;
218	$format =~ s/\n$//;	320	$format =~ s/\n$//;
219	$now = AE::now;	321	$now = _ts;
220	};	322	};
221		323
222	# format msg	324	# format msg
223	my $str = $ctx->[4]	325	my $str = $ctx->[4]
224	? $ctx->[4]($now, $_[0], $level, $format)	326	? $ctx->[4]($now, $_[0], $level, $format)
225	: $fmt ||= _format $now, $_[0], $level, $format;	327	: ($fmt[$level] ||= default_format $now, $_[0], $level, $format);
226		328
		329	$success = 1;
		330
227	$ctx->[3]($str);	331	$ctx->[3]($str)
		332	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		333	} else {
		334	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
228	}	335	}
229
230	# not masked, not consumed - propagate to parent contexts
231	push @ctx, values %{ $ctx->[2] };
232	}	336	}
233	}	337	}
234	while $ctx = pop @ctx;	338	while $ctx = pop @ctx;
235		339
236	exit 1 if $level <= 1;	340	fatal_exit if $level <= 1;
		341
		342	$success
237	}	343	}
238		344
239	sub log($$;@) {	345	sub log($$;@) {
240	_log	346	_log
241	$CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],	347	$CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
242	@_;	348	@_;
243	}	349	}
244		350
245	*AnyEvent::log = *AE::log = \&log;
246
247	=item $logger = AnyEvent::Log::logger $level[, \$enabled]	351	=item $logger = AnyEvent::Log::logger $level[, \$enabled]
248		352
249	Creates a code reference that, when called, acts as if the	353	Creates a code reference that, when called, acts as if the
250	C<AnyEvent::Log::log> function was called at this point with the givne	354	C<AnyEvent::Log::log> function was called at this point with the given
251	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with	355	level. C<$logger> is passed a C<$msg> and optional C<@args>, just as with
252	the C<AnyEvent::Log::log> function:	356	the C<AnyEvent::Log::log> function:
253		357
254	my $debug_log = AnyEvent::Log::logger "debug";	358	my $debug_log = AnyEvent::Log::logger "debug";
255		359
…		…
280	# and later in your program	384	# and later in your program
281	$debug_log->("yo, stuff here") if $debug;	385	$debug_log->("yo, stuff here") if $debug;
282		386
283	$debug and $debug_log->("123");	387	$debug and $debug_log->("123");
284		388
285	Note: currently the enabled var is always true - that will be fixed in a
286	future version :)
287
288	=cut	389	=cut
289		390
290	our %LOGGER;	391	our %LOGGER;
291		392
292	# re-assess logging status for all loggers	393	# re-assess logging status for all loggers
293	sub _reassess {	394	sub _reassess {
		395	local $SIG{__DIE__};
		396	my $die = sub { die };
		397
294	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	398	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
295	my ($ctx, $level, $renabled) = @$_;	399	my ($ctx, $level, $renabled) = @$_;
296		400
297	# to detect whether a message would be logged, we # actually	401	# to detect whether a message would be logged, we actually
298	# try to log one and die. this isn't fast, but we can be	402	# try to log one and die. this isn't fast, but we can be
299	# sure that the logging decision is correct :)	403	# sure that the logging decision is correct :)
300		404
301	$$renabled = !eval {	405	$$renabled = !eval {
302	local $SIG{__DIE__};
303
304	_log $ctx, $level, sub { die };	406	_log $ctx, $level, $die;
305		407
306	1	408	1
307	};	409	};
308
309	$$renabled = 1; # TODO
310	}	410	}
311	}	411	}
312		412
313	sub _logger {	413	sub _logger {
314	my ($ctx, $level, $renabled) = @_;	414	my ($ctx, $level, $renabled) = @_;
…		…
319		419
320	$LOGGER{$logger+0} = $logger;	420	$LOGGER{$logger+0} = $logger;
321		421
322	_reassess $logger+0;	422	_reassess $logger+0;
323		423
		424	require AnyEvent::Util unless $AnyEvent::Util::VERSION;
324	my $guard = AnyEvent::Util::guard {	425	my $guard = AnyEvent::Util::guard (sub {
325	# "clean up"	426	# "clean up"
326	delete $LOGGER{$logger+0};	427	delete $LOGGER{$logger+0};
327	};	428	});
328		429
329	sub {	430	sub {
330	$guard if 0; # keep guard alive, but don't cause runtime overhead	431	$guard if 0; # keep guard alive, but don't cause runtime overhead
331		432
332	_log $ctx, $level, @_	433	_log $ctx, $level, @_
…		…
337	sub logger($;$) {	438	sub logger($;$) {
338	_logger	439	_logger
339	$CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],	440	$CTX{ (caller)[0] } ||= _pkg_ctx +(caller)[0],
340	@_	441	@_
341	}	442	}
		443
		444	=item AnyEvent::Log::exact_time $on
		445
		446	By default, C<AnyEvent::Log> will use C<AE::now>, i.e. the cached
		447	eventloop time, for the log timestamps. After calling this function with a
		448	true value it will instead resort to C<AE::time>, i.e. fetch the current
		449	time on each log message. This only makes a difference for event loops
		450	that actually cache the time (such as L<EV> or L<AnyEvent::Loop>).
		451
		452	This setting can be changed at any time by calling this function.
		453
		454	Since C<AnyEvent::Log> has to work even before the L<AnyEvent> has been
		455	initialised, this switch will also decide whether to use C<CORE::time> or
		456	C<Time::HiRes::time> when logging a message before L<AnyEvent> becomes
		457	available.
		458
		459	=item AnyEvent::Log::format_time $timestamp
		460
		461	Formats a timestamp as returned by C<< AnyEvent->now >> or C<<
		462	AnyEvent->time >> or many other functions in the same way as
		463	C<AnyEvent::Log> does.
		464
		465	In your main program (as opposed to in your module) you can override
		466	the default timestamp display format by loading this module and then
		467	redefining this function.
		468
		469	Most commonly, this function can be used in formatting callbacks.
		470
		471	=item AnyEvent::Log::default_format $time, $ctx, $level, $msg
		472
		473	Format a log message using the given timestamp, logging context, log level
		474	and log message.
		475
		476	This is the formatting function used to format messages when no custom
		477	function is provided.
		478
		479	In your main program (as opposed to in your module) you can override the
		480	default message format by loading this module and then redefining this
		481	function.
		482
		483	=item AnyEvent::Log::fatal_exit
		484
		485	This is the function that is called after logging a C<fatal> log
		486	message. It must not return.
		487
		488	The default implementation simpl calls C<exit 1>.
		489
		490	In your main program (as opposed to in your module) you can override
		491	the fatal exit function by loading this module and then redefining this
		492	function. Make sure you don't return.
342		493
343	=back	494	=back
344		495
345	=head1 LOGGING CONTEXTS	496	=head1 LOGGING CONTEXTS
346		497
…		…
359	timestamp, context, level and string message and formats it in the way	510	timestamp, context, level and string message and formats it in the way
360	it should be logged) and a logging callback (which is responsible for	511	it should be logged) and a logging callback (which is responsible for
361	actually logging the formatted message and telling C<AnyEvent::Log>	512	actually logging the formatted message and telling C<AnyEvent::Log>
362	whether it has consumed the message, or whether it should be propagated).	513	whether it has consumed the message, or whether it should be propagated).
363		514
364	For propagation, a context can have any number of attached I<parent	515	For propagation, a context can have any number of attached I<slave
365	contexts>. Any message that is neither masked by the logging mask nor	516	contexts>. Any message that is neither masked by the logging mask nor
366	masked by the logging callback returning true will be passed to all parent	517	masked by the logging callback returning true will be passed to all slave
367	contexts.	518	contexts.
368		519
369	Each call to a logging function will log the message at most once per	520	Each call to a logging function will log the message at most once per
370	context, so it does not matter (much) if there are cycles or if the	521	context, so it does not matter (much) if there are cycles or if the
371	message can arrive at the same context via multiple paths.	522	message can arrive at the same context via multiple paths.
…		…
375	By default, all logging contexts have an full set of log levels ("all"), a	526	By default, all logging contexts have an full set of log levels ("all"), a
376	disabled logging callback and the default formatting callback.	527	disabled logging callback and the default formatting callback.
377		528
378	Package contexts have the package name as logging title by default.	529	Package contexts have the package name as logging title by default.
379		530
380	They have exactly one parent - the context of the "parent" package. The	531	They have exactly one slave - the context of the "parent" package. The
381	parent package is simply defined to be the package name without the last	532	parent package is simply defined to be the package name without the last
382	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,	533	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
383	and C<AnyEvent> becomes ... C<AnyEvent::Log::Top> which is the	534	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
384	exception of the rule - just like the parent of any package name in	535	exception of the rule - just like the "parent" of any single-component
385	Perl is C<main>, the default parent of any top-level package context is	536	package name in Perl is C<main>, the default slave of any top-level
386	C<AnyEvent::Log::Top>.	537	package context is C<$AnyEvent::Log::COLLECT>.
387		538
388	Since perl packages form only an approximate hierarchy, this parent	539	Since perl packages form only an approximate hierarchy, this slave
389	context can of course be removed.	540	context can of course be removed.
390		541
391	All other (anonymous) contexts have no parents and an empty title by	542	All other (anonymous) contexts have no slaves and an empty title by
392	default.	543	default.
393		544
394	When the module is loaded it creates the default context called	545	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
395	C<AnyEvent::Log::Default> (also stored in C<$AnyEvent::Log::Default>),	546	context that simply logs everything via C<warn>, without propagating
396	which simply logs everything via C<warn> and doesn't propagate anything
397	anywhere by default. The purpose of the default context is to provide	547	anything anywhere by default. The purpose of this context is to provide
398	a convenient place to override the global logging target or to attach	548	a convenient place to override the global logging target or to attach
399	additional log targets. It's not meant for filtering.	549	additional log targets. It's not meant for filtering.
400		550
401	It then creates the root context called C<AnyEvent::Log::Root> (also	551	It then creates the C<$AnyEvent::Log::FILTER> context whose
402	stored in C<$AnyEvent::Log::Root>) and sets its log level set to all	552	purpose is to suppress all messages with priority higher
403	levels up to the one specified by C<$ENV{PERL_ANYEVENT_VERBOSE}>. It	553	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
404	then attached the default logging context to it. The purpose of the root	554	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
405	context is to simply provide filtering according to some global log level.	555	is to simply provide filtering according to some global log level.
406		556
407	Finally it creates the top-level package context called	557	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
408	C<AnyEvent::Log::Top> (also stored in, you might have guessed,	558	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
409	C<$AnyEvent::Log::Top>) and attached the root context but otherwise leaves
410	it at default config. It's purpose is simply to collect all log messages	559	leaves it at default config. Its purpose is simply to collect all log
411	system-wide.	560	messages system-wide.
412		561
413	These three special contexts can also be referred to by the	562	The hierarchy is then:
414	package/context names C<AE::Log::Default>, C<AE::Log::Root> and
415	C<AE::Log::Top>.
416		563
		564	any package, eventually -> $COLLECT -> $FILTER -> $LOG
		565
417	The effect of all this is that log messages, by default, wander up	566	The effect of all this is that log messages, by default, wander up to the
418	to the root context where log messages with lower priority then	567	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
		568	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
419	C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered away and then to the	569	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
420	AnyEvent::Log::Default context to be passed to C<warn>.	570	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
421		571
422	Splitting the top level context into three contexts makes it easy to set	572	This makes it easy to set a global logging level (by modifying $FILTER),
423	a global logging level (by modifying the root context), but still allow	573	but still allow other contexts to send, for example, their debug and trace
424	other contexts to log, for example, their debug and trace messages to the
425	default target despite the global logging level, or to attach additional	574	messages to the $LOG target despite the global logging level, or to attach
426	log targets that log messages, regardless of the global logging level.	575	additional log targets that log messages, regardless of the global logging
		576	level.
427		577
428	It also makes it easy to replace the default warn-logger by something that	578	It also makes it easy to modify the default warn-logger ($LOG) to
429	logs to a file, or to attach additional logging targets.	579	something that logs to a file, or to attach additional logging targets
		580	(such as loggign to a file) by attaching it to $FILTER.
430		581
431	=head2 CREATING/FINDING/DESTROYING CONTEXTS	582	=head2 CREATING/FINDING/DESTROYING CONTEXTS
432		583
433	=over 4	584	=over 4
434		585
…		…
456	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	607	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
457	}	608	}
458		609
459	=item AnyEvent::Log::reset	610	=item AnyEvent::Log::reset
460		611
461	Resets all package contexts contexts and recreates the default hierarchy	612	Resets all package contexts and recreates the default hierarchy if
462	if necessary, i.e. resets the logging subsystem to defaults.	613	necessary, i.e. resets the logging subsystem to defaults, as much as
		614	possible. This process keeps references to contexts held by other parts of
		615	the program intact.
463		616
464	This can be used to implement config-file (re-)loading: before loading a	617	This can be used to implement config-file (re-)loading: before loading a
465	configuration, reset all contexts.	618	configuration, reset all contexts.
466		619
467	Note that this currently destroys all logger callbacks - bug me if you
468	need this fixed :)
469
470	=cut	620	=cut
		621
		622	our $ORIG_VERBOSE = $AnyEvent::VERBOSE;
		623	$AnyEvent::VERBOSE = 9;
471		624
472	sub reset {	625	sub reset {
473	# hard to kill complex data structures	626	# hard to kill complex data structures
474	# we recreate all package loggers and reset the hierarchy	627	# we "recreate" all package loggers and reset the hierarchy
475	while (my ($k, $v) = each %CTX) {	628	while (my ($k, $v) = each %CTX) {
476	@$v = ($k, (1 << 10) - 1 - 1, { });	629	@$v = ($k, (1 << 10) - 1 - 1, { });
477		630
478	my $pkg = $k =~ /^(.+)::/ ? $1 : "AE::Log::Top";	631	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
479	$v->attach ($CTX{$pkg});
480	}	632	}
481		633
482	$AnyEvent::Log::Default->parents;	634	@$_ = ($_->[0], (1 << 10) - 1 - 1)
483	$AnyEvent::Log::Default->title ("AnyEvent::Log::Default");	635	for $LOG, $FILTER, $COLLECT;
484	$AnyEvent::Log::Default->log_cb (sub {
485	warn shift;
486	0
487	});
488	$CTX{"AnyEvent::Log::Default"} = $CTX{"AE::Log::Default"} = $AnyEvent::Log::Default;
489		636
490	$AnyEvent::Log::Root->parents ($AnyEvent::Log::Default);	637	#$LOG->slaves;
491	$AnyEvent::Log::Root->title ("AnyEvent::Log::Root");	638	$LOG->title ('$AnyEvent::Log::LOG');
492	$AnyEvent::Log::Root->level ($AnyEvent::VERBOSE);	639	$LOG->log_to_warn;
493	$CTX{"AnyEvent::Log::Root"} = $CTX{"AE::Log::Root"} = $AnyEvent::Log::Root;
494		640
495	$AnyEvent::Log::Top->parents ($AnyEvent::Log::Root);	641	$FILTER->slaves ($LOG);
496	$AnyEvent::Log::Top->title ("AnyEvent::Log::Top");	642	$FILTER->title ('$AnyEvent::Log::FILTER');
497	$CTX{"AnyEvent::Log::Top"} = $CTX{"AE::Log::Top"} = $AnyEvent::Log::Top;	643	$FILTER->level ($ORIG_VERBOSE);
		644
		645	$COLLECT->slaves ($FILTER);
		646	$COLLECT->title ('$AnyEvent::Log::COLLECT');
498		647
499	_reassess;	648	_reassess;
500	}	649	}
501		650
		651	# override AE::log/logger
		652	*AnyEvent::log = *AE::log = \&log;
		653	*AnyEvent::logger = *AE::logger = \&logger;
		654
		655	# convert AnyEvent loggers to AnyEvent::Log loggers
		656	$_->[0] = ctx $_->[0] # convert "pkg" to "ctx"
		657	for values %LOGGER;
		658
502	# create the default logger contexts	659	# create the default logger contexts
503	$AnyEvent::Log::Default = ctx undef;	660	$LOG = ctx undef;
504	$AnyEvent::Log::Root = ctx undef;	661	$FILTER = ctx undef;
505	$AnyEvent::Log::Top = ctx undef;	662	$COLLECT = ctx undef;
506		663
507	AnyEvent::Log::reset;	664	AnyEvent::Log::reset;
508		665
509	# hello, CPAN, please catch me	666	# hello, CPAN, please catch me
510	package AnyEvent::Log::Default;
511	package AE::Log::Default;
512	package AnyEvent::Log::Root;
513	package AE::Log::Root;
514	package AnyEvent::Log::Top;	667	package AnyEvent::Log::LOG;
515	package AE::Log::Top;	668	package AE::Log::LOG;
		669	package AnyEvent::Log::FILTER;
		670	package AE::Log::FILTER;
		671	package AnyEvent::Log::COLLECT;
		672	package AE::Log::COLLECT;
516		673
517	package AnyEvent::Log::Ctx;	674	package AnyEvent::Log::Ctx;
518
519	# 0 1 2 3 4
520	# [$title, $level, %$parents, &$logcb, &$fmtcb]
521		675
522	=item $ctx = new AnyEvent::Log::Ctx methodname => param...	676	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
523		677
524	This is a convenience constructor that makes it simpler to construct	678	This is a convenience constructor that makes it simpler to construct
525	anonymous logging contexts.	679	anonymous logging contexts.
…		…
528	name as the key with the value as parameter, unless the value is an	682	name as the key with the value as parameter, unless the value is an
529	arrayref, in which case it calls the method with the contents of the	683	arrayref, in which case it calls the method with the contents of the
530	array. The methods are called in the same order as specified.	684	array. The methods are called in the same order as specified.
531		685
532	Example: create a new logging context and set both the default logging	686	Example: create a new logging context and set both the default logging
533	level, some parent contexts and a logging callback.	687	level, some slave contexts and a logging callback.
534		688
535	$ctx = new AnyEvent::Log::Ctx	689	$ctx = new AnyEvent::Log::Ctx
536	title => "dubious messages",	690	title => "dubious messages",
537	level => "error",	691	level => "error",
538	log_cb => sub { print STDOUT shift; 0 },	692	log_cb => sub { print STDOUT shift; 0 },
539	parents => [$ctx1, $ctx, $ctx2],	693	slaves => [$ctx1, $ctx, $ctx2],
540	;	694	;
541		695
542	=back	696	=back
543		697
544	=cut	698	=cut
…		…
612	Enables logging for the given levels, leaving all others unchanged.	766	Enables logging for the given levels, leaving all others unchanged.
613		767
614	=item $ctx->disable ($level[, $level...])	768	=item $ctx->disable ($level[, $level...])
615		769
616	Disables logging for the given levels, leaving all others unchanged.	770	Disables logging for the given levels, leaving all others unchanged.
		771
		772	=item $ctx->cap ($level)
		773
		774	Caps the maximum priority to the given level, for all messages logged
		775	to, or passing through, this context. That is, while this doesn't affect
		776	whether a message is logged or passed on, the maximum priority of messages
		777	will be limited to the specified level - messages with a higher priority
		778	will be set to the specified priority.
		779
		780	Another way to view this is that C<< ->level >> filters out messages with
		781	a too low priority, while C<< ->cap >> modifies messages with a too high
		782	priority.
		783
		784	This is useful when different log targets have different interpretations
		785	of priority. For example, for a specific command line program, a wrong
		786	command line switch might well result in a C<fatal> log message, while the
		787	same message, logged to syslog, is likely I<not> fatal to the system or
		788	syslog facility as a whole, but more likely a mere C<error>.
		789
		790	This can be modeled by having a stderr logger that logs messages "as-is"
		791	and a syslog logger that logs messages with a level cap of, say, C<error>,
		792	or, for truly system-critical components, actually C<critical>.
617		793
618	=cut	794	=cut
619		795
620	sub _lvl_lst {	796	sub _lvl_lst {
621	map {	797	map {
…		…
623	: $_ eq "all" ? (1 .. 9)	799	: $_ eq "all" ? (1 .. 9)
624	: $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught"	800	: $STR2LEVEL{$_} || Carp::croak "$_: not a valid logging level, caught"
625	} @_	801	} @_
626	}	802	}
627		803
		804	sub _lvl {
		805	$_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[-1]
		806	}
		807
628	our $NOP_CB = sub { 0 };	808	our $NOP_CB = sub { 0 };
629		809
630	sub levels {	810	sub levels {
631	my $ctx = shift;	811	my $ctx = shift;
632	$ctx->[1] = 0;	812	$ctx->[1] = 0;
…		…
635	AnyEvent::Log::_reassess;	815	AnyEvent::Log::_reassess;
636	}	816	}
637		817
638	sub level {	818	sub level {
639	my $ctx = shift;	819	my $ctx = shift;
640	my $lvl = $_[0] =~ /^(?:0|off|none)$/ ? 0 : (_lvl_lst $_[0])[-1];
641
642	$ctx->[1] = ((1 << $lvl) - 1) << 1;	820	$ctx->[1] = ((1 << &_lvl) - 1) << 1;
643	AnyEvent::Log::_reassess;	821	AnyEvent::Log::_reassess;
644	}	822	}
645		823
646	sub enable {	824	sub enable {
647	my $ctx = shift;	825	my $ctx = shift;
…		…
655	$ctx->[1] &= ~(1 << $_)	833	$ctx->[1] &= ~(1 << $_)
656	for &_lvl_lst;	834	for &_lvl_lst;
657	AnyEvent::Log::_reassess;	835	AnyEvent::Log::_reassess;
658	}	836	}
659		837
		838	sub cap {
		839	my $ctx = shift;
		840	$ctx->[5] = &_lvl;
		841	}
		842
660	=back	843	=back
661		844
662	=head3 PARENT CONTEXTS	845	=head3 SLAVE CONTEXTS
663		846
664	The following methods attach and detach another logging context to a	847	The following methods attach and detach another logging context to a
665	logging context.	848	logging context.
666		849
667	Log messages are propagated to all parent contexts, unless the logging	850	Log messages are propagated to all slave contexts, unless the logging
668	callback consumes the message.	851	callback consumes the message.
669		852
670	=over 4	853	=over 4
671		854
672	=item $ctx->attach ($ctx2[, $ctx3...])	855	=item $ctx->attach ($ctx2[, $ctx3...])
673		856
674	Attaches the given contexts as parents to this context. It is not an error	857	Attaches the given contexts as slaves to this context. It is not an error
675	to add a context twice (the second add will be ignored).	858	to add a context twice (the second add will be ignored).
676		859
677	A context can be specified either as package name or as a context object.	860	A context can be specified either as package name or as a context object.
678		861
679	=item $ctx->detach ($ctx2[, $ctx3...])	862	=item $ctx->detach ($ctx2[, $ctx3...])
680		863
681	Removes the given parents from this context - it's not an error to attempt	864	Removes the given slaves from this context - it's not an error to attempt
682	to remove a context that hasn't been added.	865	to remove a context that hasn't been added.
683		866
684	A context can be specified either as package name or as a context object.	867	A context can be specified either as package name or as a context object.
685		868
686	=item $ctx->parents ($ctx2[, $ctx3...])	869	=item $ctx->slaves ($ctx2[, $ctx3...])
687		870
688	Replaces all parents attached to this context by the ones given.	871	Replaces all slaves attached to this context by the ones given.
689		872
690	=cut	873	=cut
691		874
692	sub attach {	875	sub attach {
693	my $ctx = shift;	876	my $ctx = shift;
…		…
701		884
702	delete $ctx->[2]{$_+0}	885	delete $ctx->[2]{$_+0}
703	for map { AnyEvent::Log::ctx $_ } @_;	886	for map { AnyEvent::Log::ctx $_ } @_;
704	}	887	}
705		888
706	sub parents {	889	sub slaves {
707	undef $_[0][2];	890	undef $_[0][2];
708	&attach;	891	&attach;
709	}	892	}
710		893
711	=back	894	=back
712		895
713	=head3 MESSAGE LOGGING	896	=head3 LOG TARGETS
714		897
715	The following methods configure how the logging context actually does	898	The following methods configure how the logging context actually does
716	the logging (which consists of formatting the message and printing it or	899	the logging (which consists of formatting the message and printing it or
717	whatever it wants to do with it) and also allows you to log messages	900	whatever it wants to do with it).
718	directly to a context, without going via your package context.
719		901
720	=over 4	902	=over 4
721		903
722	=item $ctx->log_cb ($cb->($str))	904	=item $ctx->log_cb ($cb->($str))
723		905
…		…
728	(see C<fmt_cb> below) - normally simple text strings that end with a	910	(see C<fmt_cb> below) - normally simple text strings that end with a
729	newline (and are possibly multiline themselves).	911	newline (and are possibly multiline themselves).
730		912
731	It also has to return true iff it has consumed the log message, and false	913	It also has to return true iff it has consumed the log message, and false
732	if it hasn't. Consuming a message means that it will not be sent to any	914	if it hasn't. Consuming a message means that it will not be sent to any
733	parent context. When in doubt, return C<0> from your logging callback.	915	slave context. When in doubt, return C<0> from your logging callback.
734		916
735	Example: a very simple logging callback, simply dump the message to STDOUT	917	Example: a very simple logging callback, simply dump the message to STDOUT
736	and do not consume it.	918	and do not consume it.
737		919
738	$ctx->log_cb (sub { print STDERR shift; 0 });	920	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
746	your program.	928	your program.
747		929
748	$ctx->levels ("debug", "trace");	930	$ctx->levels ("debug", "trace");
749	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	931	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
750		932
751	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	933	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
752		934
753	Replaces the formatting callback on the context (C<undef> restores the	935	Replaces the formatting callback on the context (C<undef> restores the
754	default formatter).	936	default formatter).
755		937
756	The callback is passed the (possibly fractional) timestamp, the original	938	The callback is passed the (possibly fractional) timestamp, the original
757	logging context, the (numeric) logging level and the raw message string and needs to	939	logging context (object, not title), the (numeric) logging level and
758	return a formatted log message. In most cases this will be a string, but	940	the raw message string and needs to return a formatted log message. In
759	it could just as well be an array reference that just stores the values.	941	most cases this will be a string, but it could just as well be an array
		942	reference that just stores the values.
		943
		944	If, for some reason, you want to use C<caller> to find out more about the
		945	logger then you should walk up the call stack until you are no longer
		946	inside the C<AnyEvent::Log> package.
		947
		948	To implement your own logging callback, you might find the
		949	C<AnyEvent::Log::format_time> and C<AnyEvent::Log::default_format>
		950	functions useful.
		951
		952	Example: format the message just as AnyEvent::Log would, by letting
		953	AnyEvent::Log do the work. This is a good basis to design a formatting
		954	callback that only changes minor aspects of the formatting.
		955
		956	$ctx->fmt_cb (sub {
		957	my ($time, $ctx, $lvl, $msg) = @_;
		958
		959	AnyEvent::Log::default_format $time, $ctx, $lvl, $msg
		960	});
760		961
761	Example: format just the raw message, with numeric log level in angle	962	Example: format just the raw message, with numeric log level in angle
762	brackets.	963	brackets.
763		964
764	$ctx->fmt_cb (sub {	965	$ctx->fmt_cb (sub {
…		…
766		967
767	"<$lvl>$msg\n"	968	"<$lvl>$msg\n"
768	});	969	});
769		970
770	Example: return an array reference with just the log values, and use	971	Example: return an array reference with just the log values, and use
771	C<PApp::SQL::sql_exec> to store the emssage in a database.	972	C<PApp::SQL::sql_exec> to store the message in a database.
772		973
773	$ctx->fmt_cb (sub { \@_ });	974	$ctx->fmt_cb (sub { \@_ });
774	$ctx->log_cb (sub {	975	$ctx->log_cb (sub {
775	my ($msg) = @_;	976	my ($msg) = @_;
776		977
…		…
781	"$msg->[3]";	982	"$msg->[3]";
782		983
783	0	984	0
784	});	985	});
785		986
		987	=item $ctx->log_to_warn
		988
		989	Sets the C<log_cb> to simply use C<CORE::warn> to report any messages
		990	(usually this logs to STDERR).
		991
		992	=item $ctx->log_to_file ($path)
		993
		994	Sets the C<log_cb> to log to a file (by appending), unbuffered. The
		995	function might return before the log file has been opened or created.
		996
		997	=item $ctx->log_to_path ($path)
		998
		999	Same as C<< ->log_to_file >>, but opens the file for each message. This
		1000	is much slower, but allows you to change/move/rename/delete the file at
		1001	basically any time.
		1002
		1003	Needless(?) to say, if you do not want to be bitten by some evil person
		1004	calling C<chdir>, the path should be absolute. Doesn't help with
		1005	C<chroot>, but hey...
		1006
		1007	=item $ctx->log_to_syslog ([$facility])
		1008
		1009	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and
		1010	all the others in the obvious way. If specified, then the C<$facility> is
		1011	used as the facility (C<user>, C<auth>, C<local0> and so on). The default
		1012	facility is C<user>.
		1013
		1014	Note that this function also sets a C<fmt_cb> - the logging part requires
		1015	an array reference with [$level, $str] as input.
		1016
786	=cut	1017	=cut
787		1018
788	sub log_cb {	1019	sub log_cb {
789	my ($ctx, $cb) = @_;	1020	my ($ctx, $cb) = @_;
790		1021
…		…
795	my ($ctx, $cb) = @_;	1026	my ($ctx, $cb) = @_;
796		1027
797	$ctx->[4] = $cb;	1028	$ctx->[4] = $cb;
798	}	1029	}
799		1030
		1031	sub log_to_warn {
		1032	my ($ctx, $path) = @_;
		1033
		1034	$ctx->log_cb (sub {
		1035	warn shift;
		1036	0
		1037	});
		1038	}
		1039
		1040	# this function is a good example of why threads are a must,
		1041	# simply for priority inversion.
		1042	sub _log_to_disk {
		1043	# eval'uating this at runtime saves 220kb rss - perl has become
		1044	# an insane memory waster.
		1045	eval q{ # poor man's autoloading {}
		1046	sub _log_to_disk {
		1047	my ($ctx, $path, $keepopen) = @_;
		1048
		1049	my $fh;
		1050	my @queue;
		1051	my $delay;
		1052	my $disable;
		1053
		1054	use AnyEvent::IO ();
		1055
		1056	my $kick = sub {
		1057	undef $delay;
		1058	return unless @queue;
		1059	$delay = 1;
		1060
		1061	# we pass $kick to $kick, so $kick itself doesn't keep a reference to $kick.
		1062	my $kick = shift;
		1063
		1064	# write one or more messages
		1065	my $write = sub {
		1066	# we write as many messages as have been queued
		1067	my $data = join "", @queue;
		1068	@queue = ();
		1069
		1070	AnyEvent::IO::aio_write $fh, $data, sub {
		1071	$disable = 1;
		1072	@_
		1073	? ($_[0] == length $data or AE::log 4 => "unable to write to logfile '$path': short write")
		1074	: AE::log 4 => "unable to write to logfile '$path': $!";
		1075	undef $disable;
		1076
		1077	if ($keepopen) {
		1078	$kick->($kick);
		1079	} else {
		1080	AnyEvent::IO::aio_close ($fh, sub {
		1081	undef $fh;
		1082	$kick->($kick);
		1083	});
		1084	}
		1085	};
		1086	};
		1087
		1088	if ($fh) {
		1089	$write->();
		1090	} else {
		1091	AnyEvent::IO::aio_open
		1092	$path,
		1093	AnyEvent::IO::O_CREAT | AnyEvent::IO::O_WRONLY | AnyEvent::IO::O_APPEND,
		1094	0666,
		1095	sub {
		1096	$fh = shift
		1097	or do {
		1098	$disable = 1;
		1099	AE::log 4 => "unable to open logfile '$path': $!";
		1100	undef $disable;
		1101	return;
		1102	};
		1103
		1104	$write->();
		1105	}
		1106	;
		1107	}
		1108	};
		1109
		1110	$ctx->log_cb (sub {
		1111	return if $disable;
		1112	push @queue, shift;
		1113	$kick->($kick) unless $delay;
		1114	0
		1115	});
		1116
		1117	$kick->($kick) if $keepopen; # initial open
		1118	};
		1119	};
		1120	die if $@;
		1121	&_log_to_disk
		1122	}
		1123
		1124	sub log_to_file {
		1125	my ($ctx, $path) = @_;
		1126
		1127	_log_to_disk $ctx, $path, 1;
		1128	}
		1129
		1130	sub log_to_path {
		1131	my ($ctx, $path) = @_;
		1132
		1133	_log_to_disk $ctx, $path, 0;
		1134	}
		1135
		1136	sub log_to_syslog {
		1137	my ($ctx, $facility) = @_;
		1138
		1139	require Sys::Syslog;
		1140
		1141	$ctx->fmt_cb (sub {
		1142	my $str = $_[3];
		1143	$str =~ s/\n(?=.)/\n+ /g;
		1144
		1145	[$_[2], "($_[1][0]) $str"]
		1146	});
		1147
		1148	$facility ||= "user";
		1149
		1150	$ctx->log_cb (sub {
		1151	my $lvl = $_[0][0] < 9 ? $_[0][0] : 8;
		1152
		1153	Sys::Syslog::syslog ("$facility|" . ($lvl - 1), $_)
		1154	for split /\n/, $_[0][1];
		1155
		1156	0
		1157	});
		1158	}
		1159
		1160	=back
		1161
		1162	=head3 MESSAGE LOGGING
		1163
		1164	These methods allow you to log messages directly to a context, without
		1165	going via your package context.
		1166
		1167	=over 4
		1168
800	=item $ctx->log ($level, $msg[, @params])	1169	=item $ctx->log ($level, $msg[, @params])
801		1170
802	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	1171	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
		1172
		1173	Example: log a message in the context of another package.
		1174
		1175	(AnyEvent::Log::ctx "Other::Package")->log (warn => "heely bo");
803		1176
804	=item $logger = $ctx->logger ($level[, \$enabled])	1177	=item $logger = $ctx->logger ($level[, \$enabled])
805		1178
806	Same as C<AnyEvent::Log::logger>, but uses the given context as log	1179	Same as C<AnyEvent::Log::logger>, but uses the given context as log
807	context.	1180	context.
…		…
809	=cut	1182	=cut
810		1183
811	*log = \&AnyEvent::Log::_log;	1184	*log = \&AnyEvent::Log::_log;
812	*logger = \&AnyEvent::Log::_logger;	1185	*logger = \&AnyEvent::Log::_logger;
813		1186
814	1;
815
816	=back	1187	=back
817		1188
		1189	=cut
		1190
		1191	package AnyEvent::Log;
		1192
		1193	=head1 CONFIGURATION VIA $ENV{PERL_ANYEVENT_LOG}
		1194
		1195	Logging can also be configured by setting the environment variable
		1196	C<PERL_ANYEVENT_LOG> (or C<AE_LOG>).
		1197
		1198	The value consists of one or more logging context specifications separated
		1199	by C<:> or whitespace. Each logging specification in turn starts with a
		1200	context name, followed by C<=>, followed by zero or more comma-separated
		1201	configuration directives, here are some examples:
		1202
		1203	# set default logging level
		1204	filter=warn
		1205
		1206	# log to file instead of to stderr
		1207	log=file=/tmp/mylog
		1208
		1209	# log to file in addition to stderr
		1210	log=+%file:%file=file=/tmp/mylog
		1211
		1212	# enable debug log messages, log warnings and above to syslog
		1213	filter=debug:log=+%warnings:%warnings=warn,syslog=LOG_LOCAL0
		1214
		1215	# log trace messages (only) from AnyEvent::Debug to file
		1216	AnyEvent::Debug=+%trace:%trace=only,trace,file=/tmp/tracelog
		1217
		1218	A context name in the log specification can be any of the following:
		1219
		1220	=over 4
		1221
		1222	=item C<collect>, C<filter>, C<log>
		1223
		1224	Correspond to the three predefined C<$AnyEvent::Log::COLLECT>,
		1225	C<AnyEvent::Log::FILTER> and C<$AnyEvent::Log::LOG> contexts.
		1226
		1227	=item C<%name>
		1228
		1229	Context names starting with a C<%> are anonymous contexts created when the
		1230	name is first mentioned. The difference to package contexts is that by
		1231	default they have no attached slaves.
		1232
		1233	=item a perl package name
		1234
		1235	Any other string references the logging context associated with the given
		1236	Perl C<package>. In the unlikely case where you want to specify a package
		1237	context that matches on of the other context name forms, you can add a
		1238	C<::> to the package name to force interpretation as a package.
		1239
		1240	=back
		1241
		1242	The configuration specifications can be any number of the following:
		1243
		1244	=over 4
		1245
		1246	=item C<stderr>
		1247
		1248	Configures the context to use Perl's C<warn> function (which typically
		1249	logs to C<STDERR>). Works like C<log_to_warn>.
		1250
		1251	=item C<file=>I<path>
		1252
		1253	Configures the context to log to a file with the given path. Works like
		1254	C<log_to_file>.
		1255
		1256	=item C<path=>I<path>
		1257
		1258	Configures the context to log to a file with the given path. Works like
		1259	C<log_to_path>.
		1260
		1261	=item C<syslog> or C<syslog=>I<expr>
		1262
		1263	Configures the context to log to syslog. If I<expr> is given, then it is
		1264	evaluated in the L<Sys::Syslog> package, so you could use:
		1265
		1266	log=syslog=LOG_LOCAL0
		1267
		1268	=item C<nolog>
		1269
		1270	Configures the context to not log anything by itself, which is the
		1271	default. Same as C<< $ctx->log_cb (undef) >>.
		1272
		1273	=item C<cap=>I<level>
		1274
		1275	Caps logging messages entering this context at the given level, i.e.
		1276	reduces the priority of messages with higher priority than this level. The
		1277	default is C<0> (or C<off>), meaning the priority will not be touched.
		1278
		1279	=item C<0> or C<off>
		1280
		1281	Sets the logging level of the context to C<0>, i.e. all messages will be
		1282	filtered out.
		1283
		1284	=item C<all>
		1285
		1286	Enables all logging levels, i.e. filtering will effectively be switched
		1287	off (the default).
		1288
		1289	=item C<only>
		1290
		1291	Disables all logging levels, and changes the interpretation of following
		1292	level specifications to enable the specified level only.
		1293
		1294	Example: only enable debug messages for a context.
		1295
		1296	context=only,debug
		1297
		1298	=item C<except>
		1299
		1300	Enables all logging levels, and changes the interpretation of following
		1301	level specifications to disable that level. Rarely used.
		1302
		1303	Example: enable all logging levels except fatal and trace (this is rather
		1304	nonsensical).
		1305
		1306	filter=exept,fatal,trace
		1307
		1308	=item C<level>
		1309
		1310	Enables all logging levels, and changes the interpretation of following
		1311	level specifications to be "that level or any higher priority
		1312	message". This is the default.
		1313
		1314	Example: log anything at or above warn level.
		1315
		1316	filter=warn
		1317
		1318	# or, more verbose
		1319	filter=only,level,warn
		1320
		1321	=item C<1>..C<9> or a logging level name (C<error>, C<debug> etc.)
		1322
		1323	A numeric loglevel or the name of a loglevel will be interpreted according
		1324	to the most recent C<only>, C<except> or C<level> directive. By default,
		1325	specifying a logging level enables that and any higher priority messages.
		1326
		1327	=item C<+>I<context>
		1328
		1329	Attaches the named context as slave to the context.
		1330
		1331	=item C<+>
		1332
		1333	A lone C<+> detaches all contexts, i.e. clears the slave list from the
		1334	context. Anonymous (C<%name>) contexts have no attached slaves by default,
		1335	but package contexts have the parent context as slave by default.
		1336
		1337	Example: log messages from My::Module to a file, do not send them to the
		1338	default log collector.
		1339
		1340	My::Module=+,file=/tmp/mymodulelog
		1341
		1342	=back
		1343
		1344	Any character can be escaped by prefixing it with a C<\> (backslash), as
		1345	usual, so to log to a file containing a comma, colon, backslash and some
		1346	spaces in the filename, you would do this:
		1347
		1348	PERL_ANYEVENT_LOG='log=file=/some\ \:file\ with\,\ \\-escapes'
		1349
		1350	Since whitespace (which includes newlines) is allowed, it is fine to
		1351	specify multiple lines in C<PERL_ANYEVENT_LOG>, e.g.:
		1352
		1353	PERL_ANYEVENT_LOG="
		1354	filter=warn
		1355	AnyEvent::Debug=+%trace
		1356	%trace=only,trace,+log
		1357	" myprog
		1358
		1359	Also, in the unlikely case when you want to concatenate specifications,
		1360	use whitespace as separator, as C<::> will be interpreted as part of a
		1361	module name, an empty spec with two separators:
		1362
		1363	PERL_ANYEVENT_LOG="$PERL_ANYEVENT_LOG MyMod=debug"
		1364
		1365	=cut
		1366
		1367	for (my $spec = $ENV{PERL_ANYEVENT_LOG}) {
		1368	my %anon;
		1369
		1370	my $pkg = sub {
		1371	$_[0] eq "log" ? $LOG
		1372	: $_[0] eq "filter" ? $FILTER
		1373	: $_[0] eq "collect" ? $COLLECT
		1374	: $_[0] =~ /^%(.+)$/ ? ($anon{$1} ||= do { my $ctx = ctx undef; $ctx->[0] = $_[0]; $ctx })
		1375	: $_[0] =~ /^(.*?)(?:::)?$/ ? ctx "$1" # egad :/
		1376	: die # never reached?
		1377	};
		1378
		1379	/\G[[:space:]]+/gc; # skip initial whitespace
		1380
		1381	while (/\G((?:[^:=[:space:]]+|::|\\.)+)=/gc) {
		1382	my $ctx = $pkg->($1);
		1383	my $level = "level";
		1384
		1385	while (/\G((?:[^,:[:space:]]+|::|\\.)+)/gc) {
		1386	for ("$1") {
		1387	if ($_ eq "stderr" ) { $ctx->log_to_warn;
		1388	} elsif (/^file=(.+)/ ) { $ctx->log_to_file ("$1");
		1389	} elsif (/^path=(.+)/ ) { $ctx->log_to_path ("$1");
		1390	} elsif (/^syslog(?:=(.*))?/ ) { require Sys::Syslog; $ctx->log_to_syslog ("$1");
		1391	} elsif ($_ eq "nolog" ) { $ctx->log_cb (undef);
		1392	} elsif (/^cap=(.+)/ ) { $ctx->cap ("$1");
		1393	} elsif (/^\+(.+)$/ ) { $ctx->attach ($pkg->("$1"));
		1394	} elsif ($_ eq "+" ) { $ctx->slaves;
		1395	} elsif ($_ eq "off" or $_ eq "0") { $ctx->level (0);
		1396	} elsif ($_ eq "all" ) { $ctx->level ("all");
		1397	} elsif ($_ eq "level" ) { $ctx->level ("all"); $level = "level";
		1398	} elsif ($_ eq "only" ) { $ctx->level ("off"); $level = "enable";
		1399	} elsif ($_ eq "except" ) { $ctx->level ("all"); $level = "disable";
		1400	} elsif (/^\d$/ ) { $ctx->$level ($_);
		1401	} elsif (exists $STR2LEVEL{$_} ) { $ctx->$level ($_);
		1402	} else { die "PERL_ANYEVENT_LOG ($spec): parse error at '$_'\n";
		1403	}
		1404	}
		1405
		1406	/\G,/gc or last;
		1407	}
		1408
		1409	/\G[:[:space:]]+/gc or last;
		1410	}
		1411
		1412	/\G[[:space:]]+/gc; # skip trailing whitespace
		1413
		1414	if (/\G(.+)/g) {
		1415	die "PERL_ANYEVENT_LOG ($spec): parse error at '$1'\n";
		1416	}
		1417	}
		1418
818	=head1 EXAMPLES	1419	=head1 EXAMPLES
819		1420
820	This section shows some common configurations.	1421	This section shows some common configurations, both as code, and as
		1422	C<PERL_ANYEVENT_LOG> string.
821		1423
822	=over 4	1424	=over 4
823		1425
824	=item Setting the global logging level.	1426	=item Setting the global logging level.
825		1427
826	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before	1428	Either put C<PERL_ANYEVENT_VERBOSE=><number> into your environment before
827	running your program, or modify the log level of the root context:	1429	running your program, use C<PERL_ANYEVENT_LOG> or modify the log level of
		1430	the root context at runtime:
828		1431
829	PERL_ANYEVENT_VERBOSE=5 ./myprog	1432	PERL_ANYEVENT_VERBOSE=5 ./myprog
830		1433
		1434	PERL_ANYEVENT_LOG=log=warn
		1435
831	$AnyEvent::Log::Root->level ("warn");	1436	$AnyEvent::Log::FILTER->level ("warn");
832		1437
833	=item Append all messages to a file instead of sending them to STDERR.	1438	=item Append all messages to a file instead of sending them to STDERR.
834		1439
835	This is affected by the global logging level.	1440	This is affected by the global logging level.
836		1441
837	open my $fh, ">>", $path	1442	$AnyEvent::Log::LOG->log_to_file ($path);
838	or die "$path: $!";
839		1443
840	$AnyEvent::Log::Default->log_cb (sub {	1444	PERL_ANYEVENT_LOG=log=file=/some/path
841	syswrite $fh, shift;
842	0
843	});
844		1445
845	=item Write all messages with priority C<error> and higher to a file.	1446	=item Write all messages with priority C<error> and higher to a file.
846		1447
847	This writes them only when the global logging level allows it, because	1448	This writes them only when the global logging level allows it, because
848	it is attached to the default context which is invoked I<after> global	1449	it is attached to the default context which is invoked I<after> global
849	filtering.	1450	filtering.
850		1451
851	open my $fh, ">>", $path	1452	$AnyEvent::Log::FILTER->attach (
852	or die "$path: $!";	1453	new AnyEvent::Log::Ctx log_to_file => $path);
853		1454
854	$AnyEvent::Log::Default->attach (new AnyEvent::Log::Ctx	1455	PERL_ANYEVENT_LOG=filter=+%filelogger:%filelogger=file=/some/path
855	log_cb => sub { syswrite $fh, shift; 0 });
856		1456
857	This writes them regardless of the global logging level, because it is	1457	This writes them regardless of the global logging level, because it is
858	attached to the toplevel context, which receives all messages I<before>	1458	attached to the toplevel context, which receives all messages I<before>
859	the global filtering.	1459	the global filtering.
860		1460
861	$AnyEvent::Log::Top->attach (new AnyEvent::Log::Ctx	1461	$AnyEvent::Log::COLLECT->attach (
862	log_cb => sub { syswrite $fh, shift; 0 });	1462	new AnyEvent::Log::Ctx log_to_file => $path);
863		1463
		1464	PERL_ANYEVENT_LOG=%filelogger=file=/some/path:collect=+%filelogger
		1465
864	In both cases, messages are still written to STDOUT.	1466	In both cases, messages are still written to STDERR.
		1467
		1468	=item Additionally log all messages with C<warn> and higher priority to
		1469	C<syslog>, but cap at C<error>.
		1470
		1471	This logs all messages to the default log target, but also logs messages
		1472	with priority C<warn> or higher (and not filtered otherwise) to syslog
		1473	facility C<user>. Messages with priority higher than C<error> will be
		1474	logged with level C<error>.
		1475
		1476	$AnyEvent::Log::LOG->attach (
		1477	new AnyEvent::Log::Ctx
		1478	level => "warn",
		1479	cap => "error",
		1480	syslog => "user",
		1481	);
		1482
		1483	PERL_ANYEVENT_LOG=log=+%syslog:%syslog=warn,cap=error,syslog
865		1484
866	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).	1485	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
867		1486
868	Attach the CyAnyEvent::Log::Default> context to the C<AnyEvent::Debug>	1487	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
869	context and increase the C<AnyEvent::Debug> logging level - this simply
870	circumvents the global filtering for trace messages.	1488	context - this simply circumvents the global filtering for trace messages.
871		1489
872	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;	1490	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
873	$debug->attach ($AnyEvent::Log::Default);	1491	$debug->attach ($AnyEvent::Log::LOG);
874	$debug->levels ("trace"); # not "level"!
875		1492
876	This of course works for any package.	1493	PERL_ANYEVENT_LOG=AnyEvent::Debug=+log
		1494
		1495	This of course works for any package, not just L<AnyEvent::Debug>, but
		1496	assumes the log level for AnyEvent::Debug hasn't been changed from the
		1497	default.
877		1498
878	=back	1499	=back
879		1500
		1501	=head1 ASYNCHRONOUS DISK I/O
		1502
		1503	This module uses L<AnyEvent::IO> to actually write log messages (in
		1504	C<log_to_file> and C<log_to_path>), so it doesn't block your program when
		1505	the disk is busy and a non-blocking L<AnyEvent::IO> backend is available.
		1506
880	=head1 AUTHOR	1507	=head1 AUTHOR
881		1508
882	Marc Lehmann <schmorp@schmorp.de>	1509	Marc Lehmann <schmorp@schmorp.de>
883	http://home.schmorp.de/	1510	http://anyevent.schmorp.de
884		1511
885	=cut	1512	=cut
		1513
		1514	1
		1515

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