1Log::Dispatchouli(3) User Contributed Perl Documentation Log::Dispatchouli(3)
2
6 Log::Dispatchouli - a simple wrapper around Log::Dispatch
7
9 version 2.022
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 syslog_socket - a value for Sys::Syslog's "socket" arg; default: "native"
75 The log path is either /tmp or the value of the DISPATCHOULI_PATH env
77 var.
78 If the DISPATCHOULI_NOSYSLOG env var is true, we don't log to syslog.
80 log
82 $logger->log(@messages);
83 $logger->log(\%arg, @messages);
85 This method uses String::Flogger on the input, then unconditionally
87 logs the result. Each message is flogged individually, then joined
88 with spaces.
89 If the first argument is a hashref, it will be used as extra arguments
91 to logging. It may include a "prefix" entry to preprocess the message
92 by prepending a string (if the prefix is a string) or calling a
93 subroutine to generate a new message (if the prefix is a coderef).
94 log_fatal
96 This behaves like the "log" method, but will throw the logged string as
97 an exception after logging.
98 This method can also be called as "fatal", to match other popular
100 logging interfaces. If you want to override this method, you must
101 override "log_fatal" and not "fatal".
102 log_debug
104 This behaves like the "log" method, but will only log (at the debug
105 level) if the logger object has its debug property set to true.
106 This method can also be called as "debug", to match other popular
108 logging interfaces. If you want to override this method, you must
109 override "log_debug" and not "debug".
110 set_debug
112 $logger->set_debug($bool);
113 This sets the logger's debug property, which affects the behavior of
115 "log_debug".
116 get_debug
118 This gets the logger's debug property, which affects the behavior of
119 "log_debug".
120 clear_debug
122 This method does nothing, and is only useful for
123 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
124 below.
125 set_muted
127 $logger->set_muted($bool);
128 This sets the logger's muted property, which affects the behavior of
130 "log".
131 get_muted
133 This gets the logger's muted property, which affects the behavior of
134 "log".
135 clear_muted
137 This method does nothing, and is only useful for
138 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
139 below.
140 get_prefix
142 my $prefix = $logger->get_prefix;
143 This method returns the currently-set prefix for the logger, which may
145 be a string or code reference or undef. See Logger Prefix.
146 set_prefix
148 $logger->set_prefix( $new_prefix );
149 This method changes the prefix. See Logger Prefix.
151 clear_prefix
153 This method clears any set logger prefix. (It can also be called as
154 "unset_prefix", but this is deprecated. See Logger Prefix.
155 ident
157 This method returns the logger's ident.
158 config_id
160 This method returns the logger's configuration id, which defaults to
161 its ident. This can be used to make two loggers equivalent in
162 Log::Dispatchouli::Global so that trying to reinitialize with a new
163 logger with the same "config_id" as the current logger will not throw
164 an exception, and will simply do no thing.
165 dispatcher
167 This returns the underlying Log::Dispatch object. This is not the
168 method you're looking for. Move along.
169 stdio_dispatcher_class
171 This method is an experimental feature to allow you to pick an
172 alternate dispatch class for stderr and stdio. By default,
173 Log::Dispatch::Screen is used. This feature may go away at any time.
174
176 Log messages may be prepended with information to set context. This
177 can be set at a logger level or per log item. The simplest example is:
178 my $logger = Log::Dispatchouli->new( ... );
180 $logger->set_prefix("Batch 123: ");
182 $logger->log("begun processing");
184 # ...
186 $logger->log("finished processing");
188 The above will log something like:
190 Batch 123: begun processing
192 Batch 123: finished processing
193 To pass a prefix per-message:
195 $logger->log({ prefix => 'Sub-Item 234: ' }, 'error!')
197 # Logs: Batch 123: Sub-Item 234: error!
199 If the prefix is a string, it is prepended to each line of the message.
201 If it is a coderef, it is called and passed the message to be logged.
202 The return value is logged instead.
203 Proxy loggers also have their own prefix settings, which accumulate.
205 So:
206 my $proxy = $logger->proxy({ proxy_prefix => 'Subsystem 12: ' });
208 $proxy->set_prefix('Page 9: ');
210 $proxy->log({ prefix => 'Paragraph 6: ' }, 'Done.');
212 ...will log...
214 Batch 123: Subsystem 12: Page 9: Paragraph 6: Done.
216
218 string_flogger
219 This method returns the thing on which flog will be called to format
220 log messages. By default, it just returns "String::Flogger"
221 env_prefix
223 This method should return a string used as a prefix to find environment
224 variables that affect the logger's behavior. For example, if this
225 method returns "XYZZY" then when checking the environment for a default
226 value for the "debug" parameter, Log::Dispatchouli will first check
227 "XYZZY_DEBUG", then "DISPATCHOULI_DEBUG".
228 By default, this method returns "()", which means no extra environment
230 variable is checked.
231 env_value
233 my $value = $logger->env_value('DEBUG');
234 This method returns the value for the environment variable suffix
236 given. For example, the example given, calling with "DEBUG" will check
237 "DISPATCHOULI_DEBUG".
238
240 new_tester
241 my $logger = Log::Dispatchouli->new_tester( \%arg );
242 This returns a new logger that logs only "to_self". It's useful in
244 testing. If no "ident" arg is provided, one will be generated.
245 "log_pid" is off by default, but can be overridden.
246 "\%arg" is optional.
248 events
250 This method returns the arrayref of events logged to an array in memory
251 (in the logger). If the logger is not logging "to_self" this raises an
252 exception.
253 clear_events
255 This method empties the current sequence of events logged into an array
256 in memory. If the logger is not logging "to_self" this raises an
257 exception.
258
260 proxy
261 my $proxy_logger = $logger->proxy( \%arg );
262 This method returns a new proxy logger -- an instance of
264 Log::Dispatchouli::Proxy -- which will log through the given logger,
265 but which may have some settings localized.
266 %arg is optional. It may contain the following entries:
268 proxy_prefix
270 This is a prefix that will be applied to anything the proxy logger
271 logs, and cannot be changed.
272 debug
274 This can be set to true or false to change the proxy's "am I in
275 debug mode?" setting. It can be changed or cleared later on the
276 proxy.
277 parent
279 logger
280 These methods return the logger itself. (They're more useful when
281 called on proxy loggers.)
282
284 To provide compatibility with some other loggers, most specifically
285 Log::Contextual, the following methods are provided. You should not
286 use these methods without a good reason, and you should never subclass
287 them. Instead, subclass the methods they call.
288 is_debug
290 This method calls "get_debug".
291 is_info
293 is_fatal
294 These methods return true.
295 info
297 fatal
298 debug
299 These methods redispatch to "log", "log_fatal", and "log_debug"
300 respectively.
301
303 · Log::Dispatch
304 · String::Flogger
306
308 Ricardo SIGNES <rjbs@cpan.org>
309
311 · Christopher J. Madsen <perl@cjmweb.net>
312 · Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
314 · Dan Book <grinnz@gmail.com>
316 · George Hartzell <hartzell@alerce.com>
318 · Jon Stuart <jon@fastmailteam.com>
320 · Matt Phillips <mattp@cpan.org>
322 · Olivier Mengué <dolmen@cpan.org>
324 · Randy Stauner <randy@magnificent-tears.com>
326 · Ricardo Signes <rjbs@semiotic.systems>
328 · Ricardo Signes <rjbs@users.noreply.github.com>
330 · Sawyer X <xsawyerx@cpan.org>
332
334 This software is copyright (c) 2020 by Ricardo SIGNES.
335 This is free software; you can redistribute it and/or modify it under
337 the same terms as the Perl 5 programming language system itself.
338perl v5.32.0 2020-08-25 Log::Dispatchouli(3)