NAME¶
Log::Dispatchouli - a simple wrapper around Log::Dispatch
VERSION¶
version 2.010
SYNOPSIS¶
my $logger = Log::Dispatchouli->new({
ident => 'stuff-purger',
facility => 'daemon',
to_stdout => $opt->{print},
debug => $opt->{verbose}
});
$logger->log([ "There are %s items left to purge...", $stuff_left ]);
$logger->log_debug("this is extra often-ignored debugging log");
$logger->log_fatal("Now we will die!!");
DESCRIPTION¶
Log::Dispatchouli is a thin layer above Log::Dispatch and meant to make it dead
simple to add logging to a program without having to think much about
categories, facilities, levels, or things like that. It is meant to make
logging just configurable enough that you can find the logs you want and just
easy enough that you will actually log things.
Log::Dispatchouli can log to syslog (if you specify a facility), standard error
or standard output, to a file, or to an array in memory. That last one is
mostly useful for testing.
In addition to providing as simple a way to get a handle for logging operations,
Log::Dispatchouli uses String::Flogger to process the things to be logged,
meaning you can easily log data structures. Basically: strings are logged as
is, arrayrefs are taken as (sprintf format, args), and subroutines are called
only if needed. For more information read the String::Flogger docs.
METHODS¶
new¶
my $logger = Log::Dispatchouli->new(\%arg);
This returns a new logger, a Log::Dispatchouli object.
Valid arguments are:
ident - the name of the thing logging (mandatory)
to_self - log to the logger object for testing; default: false
to_stdout - log to STDOUT; default: false
to_stderr - log to STDERR; default: false
facility - to which syslog facility to send logs; default: none
to_file - log to PROGRAM_NAME.YYYYMMDD in the log path; default: false
log_file - a leaf name for the file to log to with to_file
log_path - path in which to log to file; defaults to DISPATCHOULI_PATH
environment variable or, failing that, to your system's tmpdir
file_format - this optional coderef is passed the message to be logged
and returns the text to write out
log_pid - if true, prefix all log entries with the pid; default: true
fail_fatal - a boolean; if true, failure to log is fatal; default: true
muted - a boolean; if true, only fatals are logged; default: false
debug - a boolean; if true, log_debug method is not a no-op
defaults to the truth of the DISPATCHOULI_DEBUG env var
quiet_fatal - 'stderr' or 'stdout' or an arrayref of zero, one, or both
fatal log messages will not be logged to these
(default: stderr)
config_id - a name for this logger's config; rarely needed!
The log path is either
/tmp or the value of the
DISPATCHOULI_PATH
env var.
If the
DISPATCHOULI_NOSYSLOG env var is true, we don't log to syslog.
log¶
$logger->log(@messages);
$logger->log(\%arg, @messages);
This method uses String::Flogger on the input, then logs the result. Each
message is flogged individually, then joined with spaces.
If the first argument is a hashref, it will be used as extra arguments to
logging. It may include a "prefix" entry to preprocess the message
by prepending a string (if the prefix is a string) or calling a subroutine to
generate a new message (if the prefix is a coderef).
log_fatal¶
This behaves like the "log" method, but will throw the logged string
as an exception after logging.
This method can also be called as "fatal", to match other popular
logging interfaces.
If you want to override this method, you must
override "log_fatal" and not
"fatal" .
log_debug¶
This behaves like the "log" method, but will only log (at the debug
level) if the logger object has its debug property set to true.
This method can also be called as "debug", to match other popular
logging interfaces.
If you want to override this method, you must
override "log_debug" and not
"debug" .
set_debug¶
$logger->set_debug($bool);
This sets the logger's debug property, which affects the behavior of
"log_debug".
get_debug¶
This gets the logger's debug property, which affects the behavior of
"log_debug".
clear_debug¶
This method does nothing, and is only useful for Log::Dispatchouli::Proxy
objects. See Methods for Proxy Loggers, below.
set_muted¶
$logger->set_muted($bool);
This sets the logger's muted property, which affects the behavior of
"log".
get_muted¶
This gets the logger's muted property, which affects the behavior of
"log".
clear_muted¶
This method does nothing, and is only useful for Log::Dispatchouli::Proxy
objects. See Methods for Proxy Loggers, below.
get_prefix¶
my $prefix = $logger->get_prefix;
This method returns the currently-set prefix for the logger, which may be a
string or code reference or undef. See Logger Prefix.
set_prefix¶
$logger->set_prefix( $new_prefix );
This method changes the prefix. See Logger Prefix.
clear_prefix¶
This method clears any set logger prefix. (It can also be called as
"unset_prefix", but this is deprecated. See Logger Prefix.
ident¶
This method returns the logger's ident.
config_id¶
This method returns the logger's configuration id, which defaults to its ident.
This can be used to make two loggers equivalent in Log::Dispatchouli::Global
so that trying to reinitialize with a new logger with the same
"config_id" as the current logger will not throw an exception, and
will simply do no thing.
dispatcher¶
This returns the underlying Log::Dispatch object. This is not the method you're
looking for. Move along.
LOGGER PREFIX¶
Log messages may be prepended with information to set context. This can be set
at a logger level or per log item. The simplest example is:
my $logger = Log::Dispatchouli->new( ... );
$logger->set_prefix("Batch 123: ");
$logger->log("begun processing");
# ...
$logger->log("finished processing");
The above will log something like:
Batch 123: begun processing
Batch 123: finished processing
To pass a prefix per-message:
$logger->log({ prefix => 'Sub-Item 234: ' }, 'error!')
# Logs: Batch 123: Sub-Item 234: error!
If the prefix is a string, it is prepended to each line of the message. If it is
a coderef, it is called and passed the message to be logged. The return value
is logged instead.
Proxy loggers also have their own prefix settings, which accumulate. So:
my $proxy = $logger->proxy({ proxy_prefix => 'Subsystem 12: ' });
$proxy->set_prefix('Page 9: ');
$proxy->log({ prefix => 'Paragraph 6: ' }, 'Done.');
...will log...
Batch 123: Subsystem 12: Page 9: Paragraph 6: Done.
METHODS FOR SUBCLASSING¶
string_flogger¶
This method returns the thing on which
flog will be called to format log
messages. By default, it just returns "String::Flogger"
env_prefix¶
This method should return a string used as a prefix to find environment
variables that affect the logger's behavior. For example, if this method
returns "XYZZY" then when checking the environment for a default
value for the "debug" parameter, Log::Dispatchouli will first check
"XYZZY_DEBUG", then "DISPATCHOULI_DEBUG".
By default, this method returns "()", which means no extra environment
variable is checked.
env_value¶
my $value = $logger->env_value('DEBUG');
This method returns the value for the environment variable suffix given. For
example, the example given, calling with "DEBUG" will check
"DISPATCHOULI_DEBUG".
METHODS FOR TESTING¶
new_tester¶
my $logger = Log::Dispatchouli->new_tester( \%arg );
This returns a new logger that logs only "to_self". It's useful in
testing. If no "ident" arg is provided, one will be generated.
"log_pid" is off by default, but can be overridden.
"\%arg" is optional.
events¶
This method returns the arrayref of events logged to an array in memory (in the
logger). If the logger is not logging "to_self" this raises an
exception.
clear_events¶
This method empties the current sequence of events logged into an array in
memory. If the logger is not logging "to_self" this raises an
exception.
METHODS FOR PROXY LOGGERS¶
proxy¶
my $proxy_logger = $logger->proxy( \%arg );
This method returns a new proxy logger -- an instance of
Log::Dispatchouli::Proxy -- which will log through the given logger, but which
may have some settings localized.
%arg is optional. It may contain the following entries:
- proxy_prefix
- This is a prefix that will be applied to anything the proxy logger logs,
and cannot be changed.
- debug
- This can be set to true or false to change the proxy's "am I in debug
mode?" setting. It can be changed or cleared later on the proxy.
parent¶
logger¶
These methods return the logger itself. (They're more useful when called on
proxy loggers.)
METHODS FOR API COMPATIBILITY¶
To provide compatibility with some other loggers, most specifically
Log::Contextual, the following methods are provided. You should not use these
methods without a good reason, and you should never subclass them. Instead,
subclass the methods they call.
- is_debug
- This method calls "get_debug".
- is_info
- is_fatal
- These methods return true.
- info
- fatal
- debug
- These methods redispatch to "log", "log_fatal", and
"log_debug" respectively.
SEE ALSO¶
- •
- Log::Dispatch
- •
- String::Flogger
AUTHOR¶
Ricardo SIGNES <rjbs@cpan.org>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2014 by Ricardo SIGNES.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.