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

Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents):
Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs.
Revision 1.20 by root, Sat Aug 20 22:27:07 2011 UTC

…		…
20	$tracer->("i am here") if $trace;	20	$tracer->("i am here") if $trace;
21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;	21	$tracer->(sub { "lots of data: " . Dumper $self }) if $trace;
22		22
23	# configuration	23	# configuration
24		24
25	# set logging for this package to maximum	25	# set logging for the current package to errors and higher only
26	AnyEvent::Log::ctx->level ("all");	26	AnyEvent::Log::ctx->level ("error");
27		27
28	# set logging globally to anything below debug	28	# set logging globally to anything below debug
29	(AnyEvent::Log::ctx "")->level ("notice");	29	$AnyEvent::Log::FILTER->level ("notice");
30		30
31	# see also EXAMPLES, below	31	# see also EXAMPLES, below
32
33	# disable logging for package "AnyEvent" and all packages below it
34	AnyEvent->AnyEvent::Log::ctx->level (0);
35
36	# log everything below debug to a file, for the whole program
37	my $ctx = AnyEvent::Log::ctx;
38	$ctx->log_cb (sub { print FILE shift; 0 });
39	(AnyEvent::Log::ctx "")->add ($ctx);
40		32
41	=head1 DESCRIPTION	33	=head1 DESCRIPTION
42		34
43	This module implements a relatively simple "logging framework". It doesn't	35	This module implements a relatively simple "logging framework". It doesn't
44	attempt to be "the" logging solution or even "a" logging solution for	36	attempt to be "the" logging solution or even "a" logging solution for
45	AnyEvent - AnyEvent simply creates logging messages internally, and this	37	AnyEvent - AnyEvent simply creates logging messages internally, and this
46	module more or less exposes the mechanism, with some extra spiff to allow	38	module more or less exposes the mechanism, with some extra spiff to allow
47	using it from other modules as well.	39	using it from other modules as well.
48		40
49	Remember that the default verbosity level is C<0>, so nothing will be	41	Remember that the default verbosity level is C<0> (C<off>), so nothing
50	logged, ever, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number	42	will be logged, unless you set C<PERL_ANYEVENT_VERBOSE> to a higher number
51	before starting your program, or change the logging level at runtime wiht	43	before starting your program, or change the logging level at runtime with
52	something like:	44	something like:
53		45
54	use AnyEvent;	46	use AnyEvent::Log;
55	(AnyEvent::Log::ctx "")->level ("info");	47	AnyEvent::Log::FILTER->level ("info");
56		48
57	The design goal behind this module was to keep it simple (and small),	49	The design goal behind this module was to keep it simple (and small),
58	but make it powerful enough to be potentially useful for any module, and	50	but make it powerful enough to be potentially useful for any module, and
59	extensive enough for the most common tasks, such as logging to multiple	51	extensive enough for the most common tasks, such as logging to multiple
60	targets, or being able to log into a database.	52	targets, or being able to log into a database.
61		53
		54	The amount of documentation might indicate otherwise, but the module is
		55	still just below 300 lines of code.
		56
		57	=head1 LOGGING LEVELS
		58
		59	Logging levels in this module range from C<1> (highest priority) to C<9>
		60	(lowest priority). Note that the lowest numerical value is the highest
		61	priority, so when this document says "higher priority" it means "lower
		62	numerical value".
		63
		64	Instead of specifying levels by name you can also specify them by aliases:
		65
		66	LVL NAME SYSLOG PERL NOTE
		67	1 fatal emerg exit aborts program!
		68	2 alert
		69	3 critical crit
		70	4 error err die
		71	5 warn warning
		72	6 note notice
		73	7 info
		74	8 debug
		75	9 trace
		76
		77	As you can see, some logging levels have multiple aliases - the first one
		78	is the "official" name, the second one the "syslog" name (if it differs)
		79	and the third one the "perl" name, suggesting that you log C<die> messages
		80	at C<error> priority.
		81
		82	You can normally only log a single message at highest priority level
		83	(C<1>, C<fatal>), because logging a fatal message will also quit the
		84	program - so use it sparingly :)
		85
		86	Some methods also offer some extra levels, such as C<0>, C<off>, C<none>
		87	or C<all> - these are only valid in the methods they are documented for.
		88
62	=head1 LOGGING FUNCTIONS	89	=head1 LOGGING FUNCTIONS
63		90
64	These functions allow you to log messages. They always use the caller's	91	These functions allow you to log messages. They always use the caller's
65	package as a "logging module/source". Also, the main logging function is	92	package as a "logging context". Also, the main logging function C<log> is
66	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is	93	callable as C<AnyEvent::log> or C<AE::log> when the C<AnyEvent> module is
67	loaded.	94	loaded.
68		95
69	=over 4	96	=over 4
70		97
…		…
75	use Carp ();	102	use Carp ();
76	use POSIX ();	103	use POSIX ();
77		104
78	use AnyEvent (); BEGIN { AnyEvent::common_sense }	105	use AnyEvent (); BEGIN { AnyEvent::common_sense }
79	use AnyEvent::Util ();	106	use AnyEvent::Util ();
		107
		108	our $VERSION = $AnyEvent::VERSION;
		109
		110	our ($COLLECT, $FILTER, $LOG);
80		111
81	our ($now_int, $now_str1, $now_str2);	112	our ($now_int, $now_str1, $now_str2);
82		113
83	# Format Time, not public - yet?	114	# Format Time, not public - yet?
84	sub ft($) {	115	sub ft($) {
…		…
89	if $now_int != $i;	120	if $now_int != $i;
90		121
91	"$now_str1$f$now_str2"	122	"$now_str1$f$now_str2"
92	}	123	}
93		124
94	our %CTX; # all logging contexts	125	our %CTX; # all package contexts
95		126
96	# creates a default package context object for the given package	127	# creates a default package context object for the given package
97	sub _pkg_ctx($) {	128	sub _pkg_ctx($) {
98	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";	129	my $ctx = bless [$_[0], (1 << 10) - 1 - 1, {}], "AnyEvent::Log::Ctx";
99		130
100	# link "parent" package	131	# link "parent" package
101	my $pkg = $_[0] =~ /^(.+)::/ ? $1 : "";	132	my $parent = $_[0] =~ /^(.+)::/
		133	? $CTX{$1} \|\|= &_pkg_ctx ("$1")
		134	: $COLLECT;
102		135
103	$pkg = $CTX{$pkg} \|\|= &_pkg_ctx ($pkg);
104	$ctx->[2]{$pkg+0} = $pkg;	136	$ctx->[2]{$parent+0} = $parent;
105		137
106	$ctx	138	$ctx
107	}	139	}
108		140
109	=item AnyEvent::Log::log $level, $msg[, @args]	141	=item AnyEvent::Log::log $level, $msg[, @args]
110		142
111	Requests logging of the given C<$msg> with the given log level (1..9).	143	Requests logging of the given C<$msg> with the given log level.
112	You can also use the following strings as log level: C<fatal> (1),
113	C<alert> (2), C<critical> (3), C<error> (4), C<warn> (5), C<note> (6),
114	C<info> (7), C<debug> (8), C<trace> (9).
115		144
116	For C<fatal> log levels, the program will abort.	145	For C<fatal> log levels, the program will abort.
117		146
118	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the	147	If only a C<$msg> is given, it is logged as-is. With extra C<@args>, the
119	C<$msg> is interpreted as an sprintf format string.	148	C<$msg> is interpreted as an sprintf format string.
…		…
132	Note that you can (and should) call this function as C<AnyEvent::log> or	161	Note that you can (and should) call this function as C<AnyEvent::log> or
133	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't	162	C<AE::log>, without C<use>-ing this module if possible (i.e. you don't
134	need any additional functionality), as those functions will load the	163	need any additional functionality), as those functions will load the
135	logging module on demand only. They are also much shorter to write.	164	logging module on demand only. They are also much shorter to write.
136		165
137	Also, if you otpionally generate a lot of debug messages (such as when	166	Also, if you optionally generate a lot of debug messages (such as when
138	tracing some code), you should look into using a logger callback and a	167	tracing some code), you should look into using a logger callback and a
139	boolean enabler (see C<logger>, below).	168	boolean enabler (see C<logger>, below).
140		169
141	Example: log something at error level.	170	Example: log something at error level.
142		171
…		…
152		181
153	=cut	182	=cut
154		183
155	# also allow syslog equivalent names	184	# also allow syslog equivalent names
156	our %STR2LEVEL = (	185	our %STR2LEVEL = (
157	fatal => 1, emerg => 1,	186	fatal => 1, emerg => 1, exit => 1,
158	alert => 2,	187	alert => 2,
159	critical => 3, crit => 3,	188	critical => 3, crit => 3,
160	error => 4, err => 4,	189	error => 4, err => 4, die => 4,
161	warn => 5, warning => 5,	190	warn => 5, warning => 5,
162	note => 6, notice => 6,	191	note => 6, notice => 6,
163	info => 7,	192	info => 7,
164	debug => 8,	193	debug => 8,
165	trace => 9,	194	trace => 9,
…		…
173		202
174	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);	203	our @LEVEL2STR = qw(0 fatal alert crit error warn note info debug trace);
175		204
176	# time, ctx, level, msg	205	# time, ctx, level, msg
177	sub _format($$$$) {	206	sub _format($$$$) {
178	my $pfx = ft $_[0];	207	my $ts = ft $_[0];
		208	my $ct = " ";
		209
179	my @res;	210	my @res;
180		211
181	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {	212	for (split /\n/, sprintf "%-5s %s: %s", $LEVEL2STR[$_[2]], $_[1][0], $_[3]) {
182	push @res, "$pfx $_\n";	213	push @res, "$ts$ct$_\n";
183	$pfx = "\t";	214	$ct = " + ";
184	}	215	}
185		216
186	join "", @res	217	join "", @res
187	}	218	}
188		219
189	sub _log {	220	sub _log {
190	my ($ctx, $level, $format, @args) = @_;	221	my ($ctx, $level, $format, @args) = @_;
191		222
		223	$level = $level > 0 && $level <= 9
		224	? $level+0
192	$level = $level > 0 && $level <= 9 ? $level+0 : $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";	225	: $STR2LEVEL{$level} \|\| Carp::croak "$level: not a valid logging level, caught";
193		226
194	my $mask = 1 << $level;	227	my $mask = 1 << $level;
195		228
196	my (@ctx, $now, $fmt);	229	my (%seen, @ctx, $now, $fmt);
197		230
198	do {	231	do
		232	{
199	# skip if masked	233	# skip if masked
200	next unless $ctx->[1] & $mask;	234	if ($ctx->[1] & $mask && !$seen{$ctx+0}++) {
201
202	if ($ctx->[3]) {	235	if ($ctx->[3]) {
203	# logging target found	236	# logging target found
204		237
205	# now get raw message, unless we have it already	238	# now get raw message, unless we have it already
206	unless ($now) {	239	unless ($now) {
207	$format = $format->() if ref $format;	240	$format = $format->() if ref $format;
208	$format = sprintf $format, @args if @args;	241	$format = sprintf $format, @args if @args;
209	$format =~ s/\n$//;	242	$format =~ s/\n$//;
210	$now = AE::now;	243	$now = AE::now;
		244	};
		245
		246	# format msg
		247	my $str = $ctx->[4]
		248	? $ctx->[4]($now, $_[0], $level, $format)
		249	: ($fmt \|\|= _format $now, $_[0], $level, $format);
		250
		251	$ctx->[3]($str, $_[0], $level)
		252	or push @ctx, values %{ $ctx->[2] }; # not consumed - propagate
		253	} else {
		254	push @ctx, values %{ $ctx->[2] }; # not masked - propagate
		255	}
211	};	256	}
212
213	# format msg
214	my $str = $ctx->[4]
215	? $ctx->[4]($now, $_[0], $level, $format)
216	: $fmt \|\|= _format $now, $_[0], $level, $format;
217
218	$ctx->[3]($str)
219	and next;
220	}	257	}
221
222	# not masked, not consume - propagate to parent contexts
223	push @ctx, values %{ $ctx->[2] };
224	} while $ctx = pop @ctx;	258	while $ctx = pop @ctx;
225		259
226	exit 1 if $level <= 1;	260	exit 1 if $level <= 1;
227	}	261	}
228		262
229	sub log($$;@) {	263	sub log($$;@) {
…		…
270	# and later in your program	304	# and later in your program
271	$debug_log->("yo, stuff here") if $debug;	305	$debug_log->("yo, stuff here") if $debug;
272		306
273	$debug and $debug_log->("123");	307	$debug and $debug_log->("123");
274		308
275	Note: currently the enabled var is always true - that will be fixed in a
276	future version :)
277
278	=cut	309	=cut
279		310
280	our %LOGGER;	311	our %LOGGER;
281		312
282	# re-assess logging status for all loggers	313	# re-assess logging status for all loggers
283	sub _reassess {	314	sub _reassess {
		315	local $SIG{__DIE__};
		316	my $die = sub { die };
		317
284	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {	318	for (@_ ? $LOGGER{$_[0]} : values %LOGGER) {
285	my ($ctx, $level, $renabled) = @$_;	319	my ($ctx, $level, $renabled) = @$_;
286		320
287	# to detetc whether a message would be logged, we # actually	321	# to detect whether a message would be logged, we actually
288	# try to log one and die. this isn't # fast, but we can be	322	# try to log one and die. this isn't fast, but we can be
289	# sure that the logging decision is correct :)	323	# sure that the logging decision is correct :)
290		324
291	$$renabled = !eval {	325	$$renabled = !eval {
292	local $SIG{__DIE__};
293
294	_log $ctx, $level, sub { die };	326	_log $ctx, $level, $die;
295		327
296	1	328	1
297	};	329	};
298
299	$$renabled = 1; # TODO
300	}	330	}
301	}	331	}
302		332
303	sub _logger($;$) {	333	sub _logger {
304	my ($ctx, $level, $renabled) = @_;	334	my ($ctx, $level, $renabled) = @_;
305
306	$renabled \|\|= \my $enabled;
307		335
308	$$renabled = 1;	336	$$renabled = 1;
309		337
310	my $logger = [$ctx, $level, $renabled];	338	my $logger = [$ctx, $level, $renabled];
311		339
…		…
351	timestamp, context, level and string message and formats it in the way	379	timestamp, context, level and string message and formats it in the way
352	it should be logged) and a logging callback (which is responsible for	380	it should be logged) and a logging callback (which is responsible for
353	actually logging the formatted message and telling C<AnyEvent::Log>	381	actually logging the formatted message and telling C<AnyEvent::Log>
354	whether it has consumed the message, or whether it should be propagated).	382	whether it has consumed the message, or whether it should be propagated).
355		383
356	For propagation, a context can have any number of attached I<parent	384	For propagation, a context can have any number of attached I<slave
357	contexts>. Any message that is neither masked by the logging mask nor	385	contexts>. Any message that is neither masked by the logging mask nor
358	masked by the logging callback returning true will be passed to all parent	386	masked by the logging callback returning true will be passed to all slave
359	contexts.	387	contexts.
		388
		389	Each call to a logging function will log the message at most once per
		390	context, so it does not matter (much) if there are cycles or if the
		391	message can arrive at the same context via multiple paths.
360		392
361	=head2 DEFAULTS	393	=head2 DEFAULTS
362		394
363	By default, all logging contexts have an full set of log levels ("all"), a	395	By default, all logging contexts have an full set of log levels ("all"), a
364	disabled logging callback and the default formatting callback.	396	disabled logging callback and the default formatting callback.
365		397
366	Package contexts have the package name as logging title by default.	398	Package contexts have the package name as logging title by default.
367		399
368	They have exactly one parent - the context of the "parent" package. The	400	They have exactly one slave - the context of the "parent" package. The
369	parent package is simply defined to be the package name without the last	401	parent package is simply defined to be the package name without the last
370	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,	402	component, i.e. C<AnyEvent::Debug::Wrapped> becomes C<AnyEvent::Debug>,
371	and C<AnyEvent> becomes the empty string.	403	and C<AnyEvent> becomes ... C<$AnyEvent::Log::COLLECT> which is the
		404	exception of the rule - just like the "parent" of any single-component
		405	package name in Perl is C<main>, the default slave of any top-level
		406	package context is C<$AnyEvent::Log::COLLECT>.
372		407
373	Since perl packages form only an approximate hierarchy, this parent	408	Since perl packages form only an approximate hierarchy, this slave
374	context can of course be removed.	409	context can of course be removed.
375		410
376	All other (anonymous) contexts have no parents and an empty title by	411	All other (anonymous) contexts have no slaves and an empty title by
377	default.	412	default.
378		413
379	When the module is first loaded, it configures the root context (the one	414	When the module is loaded it creates the C<$AnyEvent::Log::LOG> logging
380	with the empty string) to simply dump all log messages to C<STDERR>,	415	context that simply logs everything via C<warn>, without propagating
381	and sets it's log level set to all levels up to the one specified by	416	anything anywhere by default. The purpose of this context is to provide
382	C<$ENV{PERL_ANYEVENT_VERBOSE}>.	417	a convenient place to override the global logging target or to attach
		418	additional log targets. It's not meant for filtering.
		419
		420	It then creates the C<$AnyEvent::Log::FILTER> context whose
		421	purpose is to suppress all messages with priority higher
		422	than C<$ENV{PERL_ANYEVENT_VERBOSE}>. It then attached the
		423	C<$AnyEvent::Log::LOG> context to it. The purpose of the filter context
		424	is to simply provide filtering according to some global log level.
		425
		426	Finally it creates the top-level package context C<$AnyEvent::Log::COLLECT>
		427	and attaches the C<$AnyEvent::Log::FILTER> context to it, but otherwise
		428	leaves it at default config. Its purpose is simply to collect all log
		429	messages system-wide.
		430
		431	The hierarchy is then:
		432
		433	any package, eventually -> $COLLECT -> $FILTER -> $LOG
383		434
384	The effect of all this is that log messages, by default, wander up to the	435	The effect of all this is that log messages, by default, wander up to the
385	root context and will be logged to STDERR if their log level is less than	436	C<$AnyEvent::Log::COLLECT> context where all messages normally end up,
386	or equal to C<$ENV{PERL_ANYEVENT_VERBOSE}>.	437	from there to C<$AnyEvent::Log::FILTER> where log messages with lower
		438	priority then C<$ENV{PERL_ANYEVENT_VERBOSE}> will be filtered out and then
		439	to the C<$AnyEvent::Log::LOG> context to be passed to C<warn>.
387		440
		441	This makes it easy to set a global logging level (by modifying $FILTER),
		442	but still allow other contexts to send, for example, their debug and trace
		443	messages to the $LOG target despite the global logging level, or to attach
		444	additional log targets that log messages, regardless of the global logging
		445	level.
		446
		447	It also makes it easy to modify the default warn-logger ($LOG) to
		448	something that logs to a file, or to attach additional logging targets
		449	(such as loggign to a file) by attaching it to $FILTER.
		450
388	=head2 CREATING/FINDING A CONTEXT	451	=head2 CREATING/FINDING/DESTROYING CONTEXTS
389		452
390	=over 4	453	=over 4
391		454
392	=item $ctx = AnyEvent::Log::ctx [$pkg]	455	=item $ctx = AnyEvent::Log::ctx [$pkg]
393		456
…		…
411	: defined $pkg	474	: defined $pkg
412	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg	475	? $CTX{$pkg} \|\|= AnyEvent::Log::_pkg_ctx $pkg
413	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"	476	: bless [undef, (1 << 10) - 1 - 1], "AnyEvent::Log::Ctx"
414	}	477	}
415		478
416	# create default root context	479	=item AnyEvent::Log::reset
417	{	480
418	my $root = ctx undef;	481	Resets all package contexts and recreates the default hierarchy if
419	$root->[0] = "";	482	necessary, i.e. resets the logging subsystem to defaults, as much as
420	$root->title ("default");	483	possible. This process keeps references to contexts held by other parts of
421	$root->level ($AnyEvent::VERBOSE); undef $AnyEvent::VERBOSE;	484	the program intact.
		485
		486	This can be used to implement config-file (re-)loading: before loading a
		487	configuration, reset all contexts.
		488
		489	=cut
		490
		491	sub reset {
		492	# hard to kill complex data structures
		493	# we "recreate" all package loggers and reset the hierarchy
		494	while (my ($k, $v) = each %CTX) {
		495	@$v = ($k, (1 << 10) - 1 - 1, { });
		496
		497	$v->attach ($k =~ /^(.+)::/ ? $CTX{$1} : $AnyEvent::Log::COLLECT);
		498	}
		499
		500	@$_ = ($_->[0], (1 << 10) - 1 - 1)
		501	for $LOG, $FILTER, $COLLECT;
		502
		503	$LOG->slaves;
		504	$LOG->title ('$AnyEvent::Log::LOG');
422	$root->log_cb (sub {	505	$LOG->log_cb (sub {
423	print STDERR shift;	506	warn shift;
424	0	507	0
425	});	508	});
426	$CTX{""} = $root;	509
		510	$FILTER->slaves ($LOG);
		511	$FILTER->title ('$AnyEvent::Log::FILTER');
		512	$FILTER->level ($AnyEvent::VERBOSE);
		513
		514	$COLLECT->slaves ($FILTER);
		515	$COLLECT->title ('$AnyEvent::Log::COLLECT');
		516
		517	_reassess;
427	}	518	}
		519
		520	# create the default logger contexts
		521	$LOG = ctx undef;
		522	$FILTER = ctx undef;
		523	$COLLECT = ctx undef;
		524
		525	AnyEvent::Log::reset;
		526
		527	# hello, CPAN, please catch me
		528	package AnyEvent::Log::LOG;
		529	package AE::Log::LOG;
		530	package AnyEvent::Log::FILTER;
		531	package AE::Log::FILTER;
		532	package AnyEvent::Log::COLLECT;
		533	package AE::Log::COLLECT;
		534
		535	package AnyEvent::Log::Ctx;
		536
		537	# 0 1 2 3 4
		538	# [$title, $level, %$slaves, &$logcb, &$fmtcb]
		539
		540	=item $ctx = new AnyEvent::Log::Ctx methodname => param...
		541
		542	This is a convenience constructor that makes it simpler to construct
		543	anonymous logging contexts.
		544
		545	Each key-value pair results in an invocation of the method of the same
		546	name as the key with the value as parameter, unless the value is an
		547	arrayref, in which case it calls the method with the contents of the
		548	array. The methods are called in the same order as specified.
		549
		550	Example: create a new logging context and set both the default logging
		551	level, some slave contexts and a logging callback.
		552
		553	$ctx = new AnyEvent::Log::Ctx
		554	title => "dubious messages",
		555	level => "error",
		556	log_cb => sub { print STDOUT shift; 0 },
		557	slaves => [$ctx1, $ctx, $ctx2],
		558	;
428		559
429	=back	560	=back
430		561
431	=cut	562	=cut
432		563
433	package AnyEvent::Log::Ctx;	564	sub new {
		565	my $class = shift;
434		566
435	# 0 1 2 3 4	567	my $ctx = AnyEvent::Log::ctx undef;
436	# [$title, $level, %$parents, &$logcb, &$fmtcb]	568
		569	while (@_) {
		570	my ($k, $v) = splice @_, 0, 2;
		571	$ctx->$k (ref $v eq "ARRAY" ? @$v : $v);
		572	}
		573
		574	bless $ctx, $class # do we really support subclassing, hmm?
		575	}
		576
437		577
438	=head2 CONFIGURING A LOG CONTEXT	578	=head2 CONFIGURING A LOG CONTEXT
439		579
440	The following methods can be used to configure the logging context.	580	The following methods can be used to configure the logging context.
441		581
…		…
535	AnyEvent::Log::_reassess;	675	AnyEvent::Log::_reassess;
536	}	676	}
537		677
538	=back	678	=back
539		679
540	=head3 PARENT CONTEXTS	680	=head3 SLAVE CONTEXTS
541		681
542	The following methods attach and detach another logging context to a	682	The following methods attach and detach another logging context to a
543	logging context.	683	logging context.
544		684
545	Log messages are propagated to all parent contexts, unless the logging	685	Log messages are propagated to all slave contexts, unless the logging
546	callback consumes the message.	686	callback consumes the message.
547		687
548	=over 4	688	=over 4
549		689
550	=item $ctx->attach ($ctx2[, $ctx3...])	690	=item $ctx->attach ($ctx2[, $ctx3...])
551		691
552	Attaches the given contexts as parents to this context. It is not an error	692	Attaches the given contexts as slaves to this context. It is not an error
553	to add a context twice (the second add will be ignored).	693	to add a context twice (the second add will be ignored).
554		694
555	A context can be specified either as package name or as a context object.	695	A context can be specified either as package name or as a context object.
556		696
557	=item $ctx->detach ($ctx2[, $ctx3...])	697	=item $ctx->detach ($ctx2[, $ctx3...])
558		698
559	Removes the given parents from this context - it's not an error to attempt	699	Removes the given slaves from this context - it's not an error to attempt
560	to remove a context that hasn't been added.	700	to remove a context that hasn't been added.
561		701
562	A context can be specified either as package name or as a context object.	702	A context can be specified either as package name or as a context object.
		703
		704	=item $ctx->slaves ($ctx2[, $ctx3...])
		705
		706	Replaces all slaves attached to this context by the ones given.
563		707
564	=cut	708	=cut
565		709
566	sub attach {	710	sub attach {
567	my $ctx = shift;	711	my $ctx = shift;
…		…
575		719
576	delete $ctx->[2]{$_+0}	720	delete $ctx->[2]{$_+0}
577	for map { AnyEvent::Log::ctx $_ } @_;	721	for map { AnyEvent::Log::ctx $_ } @_;
578	}	722	}
579		723
		724	sub slaves {
		725	undef $_[0][2];
		726	&attach;
		727	}
		728
580	=back	729	=back
581		730
582	=head3 MESSAGE LOGGING	731	=head3 LOG TARGETS
583		732
584	The following methods configure how the logging context actually does	733	The following methods configure how the logging context actually does
585	the logging (which consists of formatting the message and printing it or	734	the logging (which consists of formatting the message and printing it or
586	whatever it wants to do with it) and also allows you to log messages	735	whatever it wants to do with it).
587	directly to a context, without going via your package context.
588		736
589	=over 4	737	=over 4
590		738
591	=item $ctx->log_cb ($cb->($str))	739	=item $ctx->log_cb ($cb->($str, $orig_ctx, $level))
592		740
593	Replaces the logging callback on the context (C<undef> disables the	741	Replaces the logging callback on the context (C<undef> disables the
594	logging callback).	742	logging callback).
595		743
596	The logging callback is responsible for handling formatted log messages	744	The logging callback is responsible for handling formatted log messages
597	(see C<fmt_cb> below) - normally simple text strings that end with a	745	(see C<fmt_cb> below) - normally simple text strings that end with a
598	newline (and are possibly multiline themselves).	746	newline (and are possibly multiline themselves). In addition to the
		747	message, which is often the only argument you need to look at, it is
		748	passed the numeric log level and originating context.
599		749
600	It also has to return true iff it has consumed the log message, and false	750	It also has to return true iff it has consumed the log message, and false
601	if it hasn't. Consuming a message means that it will not be sent to any	751	if it hasn't. Consuming a message means that it will not be sent to any
602	parent context. When in doubt, return C<0> from your logging callback.	752	slave context. When in doubt, return C<0> from your logging callback.
603		753
604	Example: a very simple logging callback, simply dump the message to STDOUT	754	Example: a very simple logging callback, simply dump the message to STDOUT
605	and do not consume it.	755	and do not consume it.
606		756
607	$ctx->log_cb (sub { print STDERR shift; 0 });	757	$ctx->log_cb (sub { print STDERR shift; 0 });
…		…
615	your program.	765	your program.
616		766
617	$ctx->levels ("debug", "trace");	767	$ctx->levels ("debug", "trace");
618	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages	768	$ctx->log_cb (sub { 1 }); # do not log, but eat debug and trace messages
619		769
		770	=item $ctx->log_to_file ($path)
		771
		772	Sets the C<log_cb> to log to a file (by appending), unbuffered.
		773
		774	=item $ctx->log_to_path ($path)
		775
		776	Same as C<< ->log_to_file >>, but opens the file for each message. This
		777	is much slower, but allows you to change/move/rename/delete the file at
		778	basically any time.
		779
		780	=item $ctx->log_to_syslog ([$log_flags])
		781
		782	Logs all messages via L<Sys::Syslog>, mapping C<trace> to C<debug> and all
		783	the others in the obvious way. If specified, then the C<$log_flags> are
		784	simply or'ed onto the priority argument and can contain any C<LOG_xxx>
		785	flags valid for Sys::Syslog::syslog, except for the priority levels.
		786
		787	Note that the default logging format includes a verbose timestamp, which
		788	is not so suited for syslog, so a simpler C<fmt_cb> might be useful:
		789
		790	$ctx->log_to_syslog;
		791	$ctx->fmt_cb (sub { "($_[1][0]) $_[3]" });
		792
620	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $ctx, $level, $message))	793	=item $ctx->fmt_cb ($fmt_cb->($timestamp, $orig_ctx, $level, $message))
621		794
622	Replaces the formatting callback on the context (C<undef> restores the	795	Replaces the formatting callback on the context (C<undef> restores the
623	default formatter).	796	default formatter).
624		797
625	The callback is passed the (possibly fractional) timestamp, the original	798	The callback is passed the (possibly fractional) timestamp, the original
626	logging context, the (numeric) logging level and the raw message string and needs to	799	logging context, the (numeric) logging level and the raw message string
627	return a formatted log message. In most cases this will be a string, but	800	and needs to return a formatted log message. In most cases this will be a
628	it could just as well be an array reference that just stores the values.	801	string, but it could just as well be an array reference that just stores
		802	the values.
		803
		804	If, for some reaosn, you want to use C<caller> to find out more baout the
		805	logger then you should walk up the call stack until you are no longer
		806	inside the C<AnyEvent::Log> package.
629		807
630	Example: format just the raw message, with numeric log level in angle	808	Example: format just the raw message, with numeric log level in angle
631	brackets.	809	brackets.
632		810
633	$ctx->fmt_cb (sub {	811	$ctx->fmt_cb (sub {
…		…
664	my ($ctx, $cb) = @_;	842	my ($ctx, $cb) = @_;
665		843
666	$ctx->[4] = $cb;	844	$ctx->[4] = $cb;
667	}	845	}
668		846
		847	sub log_to_file {
		848	my ($ctx, $path) = @_;
		849
		850	open my $fh, ">>", $path
		851	or die "$path: $!";
		852
		853	$ctx->log_cb (sub {
		854	syswrite $fh, shift;
		855	0
		856	});
		857	}
		858
		859	sub log_to_file {
		860	my ($ctx, $path) = @_;
		861
		862	$ctx->log_cb (sub {
		863	open my $fh, ">>", $path
		864	or die "$path: $!";
		865
		866	syswrite $fh, shift;
		867	0
		868	});
		869	}
		870
		871	sub log_to_syslog {
		872	my ($ctx, $flags) = @_;
		873
		874	require Sys::Syslog;
		875
		876	$ctx->log_cb (sub {
		877	my $lvl = $_[2] < 9 ? $_[2] : 8;
		878
		879	Sys::Syslog::syslog ($flags \| ($lvl - 1), $_)
		880	for split /\n/, shift;
		881
		882	0
		883	});
		884	}
		885
		886	=back
		887
		888	=head3 MESSAGE LOGGING
		889
		890	These methods allow you to log messages directly to a context, without
		891	going via your package context.
		892
		893	=over 4
		894
669	=item $ctx->log ($level, $msg[, @params])	895	=item $ctx->log ($level, $msg[, @params])
670		896
671	Same as C<AnyEvent::Log::log>, but uses the given context as log context.	897	Same as C<AnyEvent::Log::log>, but uses the given context as log context.
672		898
673	=item $logger = $ctx->logger ($level[, \$enabled])	899	=item $logger = $ctx->logger ($level[, \$enabled])
…		…
682		908
683	1;	909	1;
684		910
685	=back	911	=back
686		912
		913	=head1 EXAMPLES
		914
		915	This section shows some common configurations.
		916
		917	=over 4
		918
		919	=item Setting the global logging level.
		920
		921	Either put PERL_ANYEVENT_VERBOSE=<number> into your environment before
		922	running your program, or modify the log level of the root context:
		923
		924	PERL_ANYEVENT_VERBOSE=5 ./myprog
		925
		926	$AnyEvent::Log::FILTER->level ("warn");
		927
		928	=item Append all messages to a file instead of sending them to STDERR.
		929
		930	This is affected by the global logging level.
		931
		932	$AnyEvent::Log::LOG->log_to_file ($path); (sub {
		933
		934	=item Write all messages with priority C<error> and higher to a file.
		935
		936	This writes them only when the global logging level allows it, because
		937	it is attached to the default context which is invoked I<after> global
		938	filtering.
		939
		940	$AnyEvent::Log::FILTER->attach
		941	new AnyEvent::Log::Ctx log_to_file => $path);
		942
		943	This writes them regardless of the global logging level, because it is
		944	attached to the toplevel context, which receives all messages I<before>
		945	the global filtering.
		946
		947	$AnyEvent::Log::COLLECT->attach (
		948	new AnyEvent::Log::Ctx log_to_file => $path);
		949
		950	In both cases, messages are still written to STDERR.
		951
		952	=item Write trace messages (only) from L<AnyEvent::Debug> to the default logging target(s).
		953
		954	Attach the C<$AnyEvent::Log::LOG> context to the C<AnyEvent::Debug>
		955	context - this simply circumvents the global filtering for trace messages.
		956
		957	my $debug = AnyEvent::Debug->AnyEvent::Log::ctx;
		958	$debug->attach ($AnyEvent::Log::LOG);
		959
		960	This of course works for any package, not just L<AnyEvent::Debug>, but
		961	assumes the log level for AnyEvent::Debug hasn't been changed from the
		962	default.
		963
		964	=back
		965
687	=head1 AUTHOR	966	=head1 AUTHOR
688		967
689	Marc Lehmann <schmorp@schmorp.de>	968	Marc Lehmann <schmorp@schmorp.de>
690	http://home.schmorp.de/	969	http://home.schmorp.de/
691		970

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Comparing AnyEvent/lib/AnyEvent/Log.pm (file contents): Revision 1.10 by root, Fri Aug 19 21:17:08 2011 UTC vs. Revision 1.20 by root, Sat Aug 20 22:27:07 2011 UTC

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