Log::Dispatchouli(3) User Contributed Perl Documentation Log::Dispatchouli(3)NAMELog::Dispatchouli - a simple wrapper around Log::Dispatch
VERSION
version 2.005
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!!");
DESCRIPTIONLog::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
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) 2011 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.
perl v5.14.1 2011-04-08 Log::Dispatchouli(3)
