1Log::Dispatchouli(3) User Contributed Perl Documentation Log::Dispatchouli(3)
2
6 Log::Dispatchouli - a simple wrapper around Log::Dispatch
7
9 version 2.016
10
12 my $logger = Log::Dispatchouli->new({
13 ident => 'stuff-purger',
14 facility => 'daemon',
15 to_stdout => $opt->{print},
16 debug => $opt->{verbose}
17 });
18 $logger->log([ "There are %s items left to purge...", $stuff_left ]);
20 $logger->log_debug("this is extra often-ignored debugging log");
22 $logger->log_fatal("Now we will die!!");
24
26 Log::Dispatchouli is a thin layer above Log::Dispatch and meant to make
27 it dead simple to add logging to a program without having to think much
28 about categories, facilities, levels, or things like that. It is meant
29 to make logging just configurable enough that you can find the logs you
30 want and just easy enough that you will actually log things.
31 Log::Dispatchouli can log to syslog (if you specify a facility),
33 standard error or standard output, to a file, or to an array in memory.
34 That last one is mostly useful for testing.
35 In addition to providing as simple a way to get a handle for logging
37 operations, Log::Dispatchouli uses String::Flogger to process the
38 things to be logged, meaning you can easily log data structures.
39 Basically: strings are logged as is, arrayrefs are taken as (sprintf
40 format, args), and subroutines are called only if needed. For more
41 information read the String::Flogger docs.
42
44 new
45 my $logger = Log::Dispatchouli->new(\%arg);
46 This returns a new logger, a Log::Dispatchouli object.
48 Valid arguments are:
50 ident - the name of the thing logging (mandatory)
52 to_self - log to the logger object for testing; default: false
53 to_stdout - log to STDOUT; default: false
54 to_stderr - log to STDERR; default: false
55 facility - to which syslog facility to send logs; default: none
56 to_file - log to PROGRAM_NAME.YYYYMMDD in the log path; default: false
58 log_file - a leaf name for the file to log to with to_file
59 log_path - path in which to log to file; defaults to DISPATCHOULI_PATH
60 environment variable or, failing that, to your system's tmpdir
61 file_format - this optional coderef is passed the message to be logged
63 and returns the text to write out
64 log_pid - if true, prefix all log entries with the pid; default: true
66 fail_fatal - a boolean; if true, failure to log is fatal; default: true
67 muted - a boolean; if true, only fatals are logged; default: false
68 debug - a boolean; if true, log_debug method is not a no-op
69 defaults to the truth of the DISPATCHOULI_DEBUG env var
70 quiet_fatal - 'stderr' or 'stdout' or an arrayref of zero, one, or both
71 fatal log messages will not be logged to these
72 (default: stderr)
73 config_id - a name for this logger's config; rarely needed!
74 The log path is either /tmp or the value of the DISPATCHOULI_PATH env
76 var.
77 If the DISPATCHOULI_NOSYSLOG env var is true, we don't log to syslog.
79 log
81 $logger->log(@messages);
82 $logger->log(\%arg, @messages);
84 This method uses String::Flogger on the input, then unconditionally
86 logs the result. Each message is flogged individually, then joined
87 with spaces.
88 If the first argument is a hashref, it will be used as extra arguments
90 to logging. It may include a "prefix" entry to preprocess the message
91 by prepending a string (if the prefix is a string) or calling a
92 subroutine to generate a new message (if the prefix is a coderef).
93 log_fatal
95 This behaves like the "log" method, but will throw the logged string as
96 an exception after logging.
97 This method can also be called as "fatal", to match other popular
99 logging interfaces. If you want to override this method, you must
100 override "log_fatal" and not "fatal".
101 log_debug
103 This behaves like the "log" method, but will only log (at the debug
104 level) if the logger object has its debug property set to true.
105 This method can also be called as "debug", to match other popular
107 logging interfaces. If you want to override this method, you must
108 override "log_debug" and not "debug".
109 set_debug
111 $logger->set_debug($bool);
112 This sets the logger's debug property, which affects the behavior of
114 "log_debug".
115 get_debug
117 This gets the logger's debug property, which affects the behavior of
118 "log_debug".
119 clear_debug
121 This method does nothing, and is only useful for
122 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
123 below.
124 set_muted
126 $logger->set_muted($bool);
127 This sets the logger's muted property, which affects the behavior of
129 "log".
130 get_muted
132 This gets the logger's muted property, which affects the behavior of
133 "log".
134 clear_muted
136 This method does nothing, and is only useful for
137 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
138 below.
139 get_prefix
141 my $prefix = $logger->get_prefix;
142 This method returns the currently-set prefix for the logger, which may
144 be a string or code reference or undef. See Logger Prefix.
145 set_prefix
147 $logger->set_prefix( $new_prefix );
148 This method changes the prefix. See Logger Prefix.
150 clear_prefix
152 This method clears any set logger prefix. (It can also be called as
153 "unset_prefix", but this is deprecated. See Logger Prefix.
154 ident
156 This method returns the logger's ident.
157 config_id
159 This method returns the logger's configuration id, which defaults to
160 its ident. This can be used to make two loggers equivalent in
161 Log::Dispatchouli::Global so that trying to reinitialize with a new
162 logger with the same "config_id" as the current logger will not throw
163 an exception, and will simply do no thing.
164 dispatcher
166 This returns the underlying Log::Dispatch object. This is not the
167 method you're looking for. Move along.
168
170 Log messages may be prepended with information to set context. This
171 can be set at a logger level or per log item. The simplest example is:
172 my $logger = Log::Dispatchouli->new( ... );
174 $logger->set_prefix("Batch 123: ");
176 $logger->log("begun processing");
178 # ...
180 $logger->log("finished processing");
182 The above will log something like:
184 Batch 123: begun processing
186 Batch 123: finished processing
187 To pass a prefix per-message:
189 $logger->log({ prefix => 'Sub-Item 234: ' }, 'error!')
191 # Logs: Batch 123: Sub-Item 234: error!
193 If the prefix is a string, it is prepended to each line of the message.
195 If it is a coderef, it is called and passed the message to be logged.
196 The return value is logged instead.
197 Proxy loggers also have their own prefix settings, which accumulate.
199 So:
200 my $proxy = $logger->proxy({ proxy_prefix => 'Subsystem 12: ' });
202 $proxy->set_prefix('Page 9: ');
204 $proxy->log({ prefix => 'Paragraph 6: ' }, 'Done.');
206 ...will log...
208 Batch 123: Subsystem 12: Page 9: Paragraph 6: Done.
210
212 string_flogger
213 This method returns the thing on which flog will be called to format
214 log messages. By default, it just returns "String::Flogger"
215 env_prefix
217 This method should return a string used as a prefix to find environment
218 variables that affect the logger's behavior. For example, if this
219 method returns "XYZZY" then when checking the environment for a default
220 value for the "debug" parameter, Log::Dispatchouli will first check
221 "XYZZY_DEBUG", then "DISPATCHOULI_DEBUG".
222 By default, this method returns "()", which means no extra environment
224 variable is checked.
225 env_value
227 my $value = $logger->env_value('DEBUG');
228 This method returns the value for the environment variable suffix
230 given. For example, the example given, calling with "DEBUG" will check
231 "DISPATCHOULI_DEBUG".
232
234 new_tester
235 my $logger = Log::Dispatchouli->new_tester( \%arg );
236 This returns a new logger that logs only "to_self". It's useful in
238 testing. If no "ident" arg is provided, one will be generated.
239 "log_pid" is off by default, but can be overridden.
240 "\%arg" is optional.
242 events
244 This method returns the arrayref of events logged to an array in memory
245 (in the logger). If the logger is not logging "to_self" this raises an
246 exception.
247 clear_events
249 This method empties the current sequence of events logged into an array
250 in memory. If the logger is not logging "to_self" this raises an
251 exception.
252
254 proxy
255 my $proxy_logger = $logger->proxy( \%arg );
256 This method returns a new proxy logger -- an instance of
258 Log::Dispatchouli::Proxy -- which will log through the given logger,
259 but which may have some settings localized.
260 %arg is optional. It may contain the following entries:
262 proxy_prefix
264 This is a prefix that will be applied to anything the proxy logger
265 logs, and cannot be changed.
266 debug
268 This can be set to true or false to change the proxy's "am I in
269 debug mode?" setting. It can be changed or cleared later on the
270 proxy.
271 parent
273 logger
274 These methods return the logger itself. (They're more useful when
275 called on proxy loggers.)
276
278 To provide compatibility with some other loggers, most specifically
279 Log::Contextual, the following methods are provided. You should not
280 use these methods without a good reason, and you should never subclass
281 them. Instead, subclass the methods they call.
282 is_debug
284 This method calls "get_debug".
285 is_info
287 is_fatal
288 These methods return true.
289 info
291 fatal
292 debug
293 These methods redispatch to "log", "log_fatal", and "log_debug"
294 respectively.
295
297 · Log::Dispatch
298 · String::Flogger
300
302 Ricardo SIGNES <rjbs@cpan.org>
303
305 · Christopher J. Madsen <perl@cjmweb.net>
306 · Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
308 · Dan Book <grinnz@gmail.com>
310 · George Hartzell <hartzell@alerce.com>
312 · Matt Phillips <mattp@cpan.org>
314 · Olivier Mengué <dolmen@cpan.org>
316 · Randy Stauner <randy@magnificent-tears.com>
318 · Sawyer X <xsawyerx@cpan.org>
320
322 This software is copyright (c) 2018 by Ricardo SIGNES.
323 This is free software; you can redistribute it and/or modify it under
325 the same terms as the Perl 5 programming language system itself.
326perl v5.28.0 2018-02-21 Log::Dispatchouli(3)