1 package Log::Contextual;
6 our $VERSION = '0.004100';
8 my @levels = qw(debug trace warn info error fatal);
10 use Exporter::Declare;
11 use Exporter::Declare::Export::Generator;
12 use Data::Dumper::Concise;
13 use Scalar::Util 'blessed';
15 my @dlog = ((map "Dlog_$_", @levels), (map "DlogS_$_", @levels));
17 my @log = ((map "log_$_", @levels), (map "logS_$_", @levels));
20 require Log::Log4perl;
21 die if $Log::Log4perl::VERSION < 1.29;
22 Log::Log4perl->wrapper_register(__PACKAGE__)
25 # ____ is because tags must have at least one export and we don't want to
26 # export anything but the levels selected
31 qw( set_logger with_logger )
34 export_tag dlog => ('____');
35 export_tag log => ('____');
36 import_arguments qw(logger package_logger default_logger);
39 my ($class, $importer, $spec) = @_;
41 die 'Log::Contextual does not have a default import list'
42 if $spec->config->{default};
44 my @levels = @{$class->arg_levels($spec->config->{levels})};
45 for my $level (@levels) {
46 if ($spec->config->{log}) {
47 $spec->add_export("&log_$level", sub (&@) {
48 _do_log( $level => _get_logger( caller ), shift @_, @_)
50 $spec->add_export("&logS_$level", sub (&@) {
51 _do_logS( $level => _get_logger( caller ), $_[0], $_[1])
54 if ($spec->config->{dlog}) {
55 $spec->add_export("&Dlog_$level", sub (&@) {
56 my ($code, @args) = @_;
57 return _do_log( $level => _get_logger( caller ), sub {
58 local $_ = (@args?Data::Dumper::Concise::Dumper @args:'()');
62 $spec->add_export("&DlogS_$level", sub (&$) {
63 my ($code, $ref) = @_;
64 _do_logS( $level => _get_logger( caller ), sub {
65 local $_ = Data::Dumper::Concise::Dumper $ref;
73 sub arg_logger { $_[1] }
74 sub arg_levels { $_[1] || [qw(debug trace warn info error fatal)] }
75 sub arg_package_logger { $_[1] }
76 sub arg_default_logger { $_[1] }
79 my ($class, $importer, $specs) = @_;
81 if (my $l = $class->arg_logger($specs->config->{logger})) {
85 if (my $l = $class->arg_package_logger($specs->config->{package_logger})) {
86 _set_package_logger_for($importer, $l)
89 if (my $l = $class->arg_default_logger($specs->config->{default_logger})) {
90 _set_default_logger_for($importer, $l)
98 sub _set_default_logger_for {
100 if(ref $logger ne 'CODE') {
101 die 'logger was not a CodeRef or a logger object. Please try again.'
102 unless blessed($logger);
103 $logger = do { my $l = $logger; sub { $l } }
105 $Default_Logger{$_[0]} = $logger
108 sub _set_package_logger_for {
110 if(ref $logger ne 'CODE') {
111 die 'logger was not a CodeRef or a logger object. Please try again.'
112 unless blessed($logger);
113 $logger = do { my $l = $logger; sub { $l } }
115 $Package_Logger{$_[0]} = $logger
121 $Package_Logger{$package} ||
123 $Default_Logger{$package} ||
124 die q( no logger set! you can't try to log something without a logger! )
130 if(ref $logger ne 'CODE') {
131 die 'logger was not a CodeRef or a logger object. Please try again.'
132 unless blessed($logger);
133 $logger = do { my $l = $logger; sub { $l } }
136 warn 'set_logger (or -logger) called more than once! This is a bad idea!'
138 $Get_Logger = $logger;
143 if(ref $logger ne 'CODE') {
144 die 'logger was not a CodeRef or a logger object. Please try again.'
145 unless blessed($logger);
146 $logger = do { my $l = $logger; sub { $l } }
148 local $Get_Logger = $logger;
158 $logger->$level($code->(@_))
159 if $logger->${\"is_$level"};
169 $logger->$level($code->($value))
170 if $logger->${\"is_$level"};
180 Log::Contextual - Simple logging interface with a contextual log
184 use Log::Contextual qw( :log :dlog set_logger with_logger );
185 use Log::Contextual::SimpleLogger;
186 use Log::Log4perl ':easy';
187 Log::Log4perl->easy_init($DEBUG);
190 my $logger = Log::Log4perl->get_logger;
194 log_debug { 'program started' };
198 my $minilogger = Log::Contextual::SimpleLogger->new({
199 levels => [qw( trace debug )]
202 with_logger $minilogger => sub {
203 log_trace { 'foo entered' };
204 my ($foo, $bar) = Dlog_trace { "params for foo: $_" } @_;
206 log_trace { 'foo left' };
212 Beginning with version 1.008 L<Log::Dispatchouli> also works out of the box
213 with C<Log::Contextual>:
215 use Log::Contextual qw( :log :dlog set_logger );
216 use Log::Dispatchouli;
217 my $ld = Log::Dispatchouli->new({
218 ident => 'slrtbrfst',
225 log_debug { 'program started' };
229 This module is a simple interface to extensible logging. It is bundled with a
230 really basic logger, L<Log::Contextual::SimpleLogger>, but in general you
231 should use a real logger instead of that. For something more serious but not
232 overly complicated, try L<Log::Dispatchouli> (see L</SYNOPSIS> for example.)
234 The reason for this module is to abstract your logging interface so that
235 logging is as painless as possible, while still allowing you to switch from one
238 =head1 A WORK IN PROGRESS
240 This module is certainly not complete, but we will not break the interface
241 lightly, so I would say it's safe to use in production code. The main result
242 from that at this point is that doing:
246 will die as we do not yet know what the defaults should be. If it turns out
247 that nearly everyone uses the C<:log> tag and C<:dlog> is really rare, we'll
248 probably make C<:log> the default. But only time and usage will tell.
250 =head1 IMPORT OPTIONS
252 See L</SETTING DEFAULT IMPORT OPTIONS> for information on setting these project
257 When you import this module you may use C<-logger> as a shortcut for
258 L<set_logger>, for example:
260 use Log::Contextual::SimpleLogger;
261 use Log::Contextual qw( :dlog ),
262 -logger => Log::Contextual::SimpleLogger->new({ levels => [qw( debug )] });
264 sometimes you might want to have the logger handy for other stuff, in which
265 case you might try something like the following:
268 BEGIN { $var_log = VarLogger->new }
269 use Log::Contextual qw( :dlog ), -logger => $var_log;
273 The C<-levels> import option allows you to define exactly which levels your
274 logger supports. So the default,
275 C<< [qw(debug trace warn info error fatal)] >>, works great for
276 L<Log::Log4perl>, but it doesn't support the levels for L<Log::Dispatch>. But
277 supporting those levels is as easy as doing
280 -levels => [qw( debug info notice warning error critical alert emergency )];
282 =head2 -package_logger
284 The C<-package_logger> import option is similar to the C<-logger> import option
285 except C<-package_logger> sets the the logger for the current package.
287 Unlike L</-default_logger>, C<-package_logger> cannot be overridden with
291 use Log::Contextual::SimpleLogger;
292 use Log::Contextual qw( :log ),
293 -package_logger => Log::Contextual::WarnLogger->new({
294 env_prefix => 'MY_PACKAGE'
297 If you are interested in using this package for a module you are putting on
298 CPAN we recommend L<Log::Contextual::WarnLogger> for your package logger.
300 =head2 -default_logger
302 The C<-default_logger> import option is similar to the C<-logger> import option
303 except C<-default_logger> sets the the B<default> logger for the current package.
305 Basically it sets the logger to be used if C<set_logger> is never called; so
308 use Log::Contextual::SimpleLogger;
309 use Log::Contextual qw( :log ),
310 -default_logger => Log::Contextual::WarnLogger->new({
311 env_prefix => 'MY_PACKAGE'
314 =head1 SETTING DEFAULT IMPORT OPTIONS
316 Eventually you will get tired of writing the following in every single one of
320 use Log::Log4perl ':easy';
321 BEGIN { Log::Log4perl->easy_init($DEBUG) }
323 use Log::Contextual -logger => Log::Log4perl->get_logger;
325 You can set any of the import options for your whole project if you define your
326 own C<Log::Contextual> subclass as follows:
328 package MyApp::Log::Contextual;
330 use base 'Log::Contextual';
332 use Log::Log4perl ':easy';
333 Log::Log4perl->easy_init($DEBUG)
335 sub arg_default_logger { $_[1] || Log::Log4perl->get_logger }
336 sub arg_levels { [qw(debug trace warn info error fatal custom_level)] }
338 # or maybe instead of default_logger
339 sub arg_package_logger { $_[1] }
341 # and almost definitely not this, which is only here for completeness
342 sub arg_logger { $_[1] }
344 Note the C<< $_[1] || >> in C<arg_default_logger>. All of these methods are
345 passed the values passed in from the arguments to the subclass, so you can
346 either throw them away, honor them, die on usage, or whatever. To be clear,
347 if you define your subclass, and someone uses it as follows:
349 use MyApp::Log::Contextual -default_logger => $foo,
350 -levels => [qw(bar baz biff)];
352 Your C<arg_default_logger> method will get C<$foo> and your C<arg_levels>
353 will get C<[qw(bar baz biff)]>;
359 my $logger = WarnLogger->new;
362 Arguments: C<Ref|CodeRef $returning_logger>
364 C<set_logger> will just set the current logger to whatever you pass it. It
365 expects a C<CodeRef>, but if you pass it something else it will wrap it in a
366 C<CodeRef> for you. C<set_logger> is really meant only to be called from a
367 top-level script. To avoid foot-shooting the function will warn if you call it
372 my $logger = WarnLogger->new;
373 with_logger $logger => sub {
375 log_fatal { 'Non Logical Universe Detected' };
377 log_info { 'All is good' };
381 Arguments: C<Ref|CodeRef $returning_logger, CodeRef $to_execute>
383 C<with_logger> sets the logger for the scope of the C<CodeRef> C<$to_execute>.
384 As with L</set_logger>, C<with_logger> will wrap C<$returning_logger> with a
385 C<CodeRef> if needed.
391 Arguments: C<CodeRef $returning_message, @args>
393 C<log_$level> functions all work the same except that a different method
394 is called on the underlying C<$logger> object. The basic pattern is:
396 sub log_$level (&@) {
397 if ($logger->is_$level) {
398 $logger->$level(shift->(@_));
403 Note that the function returns it's arguments. This can be used in a number of
404 ways, but often it's convenient just for partial inspection of passthrough data
406 my @friends = log_trace {
407 'friends list being generated, data from first friend: ' .
408 Dumper($_[0]->TO_JSON)
409 } generate_friend_list();
411 If you want complete inspection of passthrough data, take a look at the
412 L</Dlog_$level> functions.
414 Which functions are exported depends on what was passed to L</-levels>. The
415 default (no C<-levels> option passed) would export:
437 Arguments: C<CodeRef $returning_message, Item $arg>
439 This is really just a special case of the L</log_$level> functions. It forces
440 scalar context when that is what you need. Other than that it works exactly
443 my $friend = logS_trace {
444 'I only have one friend: ' . Dumper($_[0]->TO_JSON)
447 See also: L</DlogS_$level>.
453 Arguments: C<CodeRef $returning_message, @args>
455 All of the following six functions work the same as their L</log_$level>
456 brethren, except they return what is passed into them and put the stringified
457 (with L<Data::Dumper::Concise>) version of their args into C<$_>. This means
458 you can do cool things like the following:
460 my @nicks = Dlog_debug { "names: $_" } map $_->value, $frew->names->all;
462 and the output might look something like:
470 Which functions are exported depends on what was passed to L</-levels>. The
471 default (no C<-levels> option passed) would export:
493 Arguments: C<CodeRef $returning_message, Item $arg>
495 Like L</logS_$level>, these functions are a special case of L</Dlog_$level>.
496 They only take a single scalar after the C<$returning_message> instead of
497 slurping up (and also setting C<wantarray>) all the C<@args>
499 my $pals_rs = DlogS_debug { "pals resultset: $_" }
500 $schema->resultset('Pals')->search({ perlers => 1 });
502 =head1 LOGGER INTERFACE
504 Because this module is ultimately pretty looking glue (glittery?) with the
505 awesome benefit of the Contextual part, users will often want to make their
506 favorite logger work with it. The following are the methods that should be
507 implemented in the logger:
522 The first six merely need to return true if that level is enabled. The latter
523 six take the results of whatever the user returned from their coderef and log
524 them. For a basic example see L<Log::Contextual::SimpleLogger>.
528 frew - Arthur Axel "fREW" Schmidt <frioux@gmail.com>
532 mst - Matt S. Trout <mst@shadowcat.co.uk>
536 Copyright (c) 2010 the Log::Contextual L</AUTHOR> and L</DESIGNER> as listed
541 This library is free software and may be distributed under the same terms as