1Log::Dispatchouli(3) User Contributed Perl Documentation Log::Dispatchouli(3)
2
6 Log::Dispatchouli - a simple wrapper around Log::Dispatch
7
9 version 2.023
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 This module has a long-term perl support period. That means it will
45 not require a version of perl released fewer than five years ago.
46 Although it may work on older versions of perl, no guarantee is made
48 that the minimum required version will not be increased. The version
49 may be increased for any reason, and there is no promise that patches
50 will be accepted to lower the minimum required perl.
51
53 new
54 my $logger = Log::Dispatchouli->new(\%arg);
55 This returns a new logger, a Log::Dispatchouli object.
57 Valid arguments are:
59 ident - the name of the thing logging (mandatory)
61 to_self - log to the logger object for testing; default: false
62 to_stdout - log to STDOUT; default: false
63 to_stderr - log to STDERR; default: false
64 facility - to which syslog facility to send logs; default: none
65 to_file - log to PROGRAM_NAME.YYYYMMDD in the log path; default: false
67 log_file - a leaf name for the file to log to with to_file
68 log_path - path in which to log to file; defaults to DISPATCHOULI_PATH
69 environment variable or, failing that, to your system's tmpdir
70 file_format - this optional coderef is passed the message to be logged
72 and returns the text to write out
73 log_pid - if true, prefix all log entries with the pid; default: true
75 fail_fatal - a boolean; if true, failure to log is fatal; default: true
76 muted - a boolean; if true, only fatals are logged; default: false
77 debug - a boolean; if true, log_debug method is not a no-op
78 defaults to the truth of the DISPATCHOULI_DEBUG env var
79 quiet_fatal - 'stderr' or 'stdout' or an arrayref of zero, one, or both
80 fatal log messages will not be logged to these
81 (default: stderr)
82 config_id - a name for this logger's config; rarely needed!
83 syslog_socket - a value for Sys::Syslog's "socket" arg; default: "native"
84 The log path is either /tmp or the value of the DISPATCHOULI_PATH env
86 var.
87 If the DISPATCHOULI_NOSYSLOG env var is true, we don't log to syslog.
89 log
91 $logger->log(@messages);
92 $logger->log(\%arg, @messages);
94 This method uses String::Flogger on the input, then unconditionally
96 logs the result. Each message is flogged individually, then joined
97 with spaces.
98 If the first argument is a hashref, it will be used as extra arguments
100 to logging. It may include a "prefix" entry to preprocess the message
101 by prepending a string (if the prefix is a string) or calling a
102 subroutine to generate a new message (if the prefix is a coderef).
103 log_fatal
105 This behaves like the "log" method, but will throw the logged string as
106 an exception after logging.
107 This method can also be called as "fatal", to match other popular
109 logging interfaces. If you want to override this method, you must
110 override "log_fatal" and not "fatal".
111 log_debug
113 This behaves like the "log" method, but will only log (at the debug
114 level) if the logger object has its debug property set to true.
115 This method can also be called as "debug", to match other popular
117 logging interfaces. If you want to override this method, you must
118 override "log_debug" and not "debug".
119 set_debug
121 $logger->set_debug($bool);
122 This sets the logger's debug property, which affects the behavior of
124 "log_debug".
125 get_debug
127 This gets the logger's debug property, which affects the behavior of
128 "log_debug".
129 clear_debug
131 This method does nothing, and is only useful for
132 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
133 below.
134 set_muted
136 $logger->set_muted($bool);
137 This sets the logger's muted property, which affects the behavior of
139 "log".
140 get_muted
142 This gets the logger's muted property, which affects the behavior of
143 "log".
144 clear_muted
146 This method does nothing, and is only useful for
147 Log::Dispatchouli::Proxy objects. See Methods for Proxy Loggers,
148 below.
149 get_prefix
151 my $prefix = $logger->get_prefix;
152 This method returns the currently-set prefix for the logger, which may
154 be a string or code reference or undef. See Logger Prefix.
155 set_prefix
157 $logger->set_prefix( $new_prefix );
158 This method changes the prefix. See Logger Prefix.
160 clear_prefix
162 This method clears any set logger prefix. (It can also be called as
163 "unset_prefix", but this is deprecated. See Logger Prefix.
164 ident
166 This method returns the logger's ident.
167 config_id
169 This method returns the logger's configuration id, which defaults to
170 its ident. This can be used to make two loggers equivalent in
171 Log::Dispatchouli::Global so that trying to reinitialize with a new
172 logger with the same "config_id" as the current logger will not throw
173 an exception, and will simply do no thing.
174 dispatcher
176 This returns the underlying Log::Dispatch object. This is not the
177 method you're looking for. Move along.
178 stdio_dispatcher_class
180 This method is an experimental feature to allow you to pick an
181 alternate dispatch class for stderr and stdio. By default,
182 Log::Dispatch::Screen is used. This feature may go away at any time.
183
185 Log messages may be prepended with information to set context. This
186 can be set at a logger level or per log item. The simplest example is:
187 my $logger = Log::Dispatchouli->new( ... );
189 $logger->set_prefix("Batch 123: ");
191 $logger->log("begun processing");
193 # ...
195 $logger->log("finished processing");
197 The above will log something like:
199 Batch 123: begun processing
201 Batch 123: finished processing
202 To pass a prefix per-message:
204 $logger->log({ prefix => 'Sub-Item 234: ' }, 'error!')
206 # Logs: Batch 123: Sub-Item 234: error!
208 If the prefix is a string, it is prepended to each line of the message.
210 If it is a coderef, it is called and passed the message to be logged.
211 The return value is logged instead.
212 Proxy loggers also have their own prefix settings, which accumulate.
214 So:
215 my $proxy = $logger->proxy({ proxy_prefix => 'Subsystem 12: ' });
217 $proxy->set_prefix('Page 9: ');
219 $proxy->log({ prefix => 'Paragraph 6: ' }, 'Done.');
221 ...will log...
223 Batch 123: Subsystem 12: Page 9: Paragraph 6: Done.
225
227 string_flogger
228 This method returns the thing on which flog will be called to format
229 log messages. By default, it just returns "String::Flogger"
230 env_prefix
232 This method should return a string used as a prefix to find environment
233 variables that affect the logger's behavior. For example, if this
234 method returns "XYZZY" then when checking the environment for a default
235 value for the "debug" parameter, Log::Dispatchouli will first check
236 "XYZZY_DEBUG", then "DISPATCHOULI_DEBUG".
237 By default, this method returns "()", which means no extra environment
239 variable is checked.
240 env_value
242 my $value = $logger->env_value('DEBUG');
243 This method returns the value for the environment variable suffix
245 given. For example, the example given, calling with "DEBUG" will check
246 "DISPATCHOULI_DEBUG".
247
249 new_tester
250 my $logger = Log::Dispatchouli->new_tester( \%arg );
251 This returns a new logger that logs only "to_self". It's useful in
253 testing. If no "ident" arg is provided, one will be generated.
254 "log_pid" is off by default, but can be overridden.
255 "\%arg" is optional.
257 events
259 This method returns the arrayref of events logged to an array in memory
260 (in the logger). If the logger is not logging "to_self" this raises an
261 exception.
262 clear_events
264 This method empties the current sequence of events logged into an array
265 in memory. If the logger is not logging "to_self" this raises an
266 exception.
267
269 proxy
270 my $proxy_logger = $logger->proxy( \%arg );
271 This method returns a new proxy logger -- an instance of
273 Log::Dispatchouli::Proxy -- which will log through the given logger,
274 but which may have some settings localized.
275 %arg is optional. It may contain the following entries:
277 proxy_prefix
279 This is a prefix that will be applied to anything the proxy logger
280 logs, and cannot be changed.
281 debug
283 This can be set to true or false to change the proxy's "am I in
284 debug mode?" setting. It can be changed or cleared later on the
285 proxy.
286 parent
288 logger
289 These methods return the logger itself. (They're more useful when
290 called on proxy loggers.)
291
293 To provide compatibility with some other loggers, most specifically
294 Log::Contextual, the following methods are provided. You should not
295 use these methods without a good reason, and you should never subclass
296 them. Instead, subclass the methods they call.
297 is_debug
299 This method calls "get_debug".
300 is_info
302 is_fatal
303 These methods return true.
304 info
306 fatal
307 debug
308 These methods redispatch to "log", "log_fatal", and "log_debug"
309 respectively.
310
312 • Log::Dispatch
313 • String::Flogger
315
317 Ricardo SIGNES <rjbs@semiotic.systems>
318
320 • Christopher J. Madsen <perl@cjmweb.net>
321 • Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
323 • Dan Book <grinnz@gmail.com>
325 • George Hartzell <hartzell@alerce.com>
327 • Jon Stuart <jon@fastmailteam.com>
329 • Matt Phillips <mattp@cpan.org>
331 • Olivier Mengué <dolmen@cpan.org>
333 • Randy Stauner <randy@magnificent-tears.com>
335 • Ricardo Signes <rjbs@users.noreply.github.com>
337 • Sawyer X <xsawyerx@cpan.org>
339
341 This software is copyright (c) 2021 by Ricardo SIGNES.
342 This is free software; you can redistribute it and/or modify it under
344 the same terms as the Perl 5 programming language system itself.
345perl v5.36.0 2022-07-22 Log::Dispatchouli(3)