In your config.yml
logger: log4perl log: core log4perl: config_file: log4perl.conf
In your log4perl.conf
log4perl.rootLogger = DEBUG, LOG1 log4perl.appender.LOG1 = Log::Log4perl::Appender::File log4perl.appender.LOG1.filename = /var/log/mylog.log log4perl.appender.LOG1.mode = append log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
This class is an interface between Dancer's logging engine abstraction layer and the Log::Log4perl library. In order to use it, you have to set the logger engine to log4perl.
logger
log4perl
You can use either Log::Log4perl or Log::Log4perl::Tiny. If you want to use the latter, just specify the tiny option in the specific configuration.
tiny
You can decide to let the module perform the initialisation of the logging system, or you can do it by yourself. In the latter case, you can pass the no_init parameter, which instructs the module not to perform the initialisation.
no_init
After initialisation, you can decide to use Dancer's functions or the ones provided by either Log::Log4perl or Log::Log4perl::Tiny, e.g. the stealth loggers in case of a simplified interface.
Note that Dancer's log and logger_format options are still honored, which means you need to be aware of the following:
log
logger_format
logger_format is still processed and becomes %m in Log4perl's format placeholders. This allows you to pass Dancer placeholders that aren't available as Log4perl placeholders.
%m
Dancer's core level messages are passed to Log4perl as level trace but will not be passed unless Dancer's log config is core.
core
trace
log should be set a lower priority than the lowest priority as set in your Log4perl configuration. If it isn't, Dancer::Logger::Abstract will not pass the message to Log4perl.
The configuration capabilities vary depending on the underlying library you have, even though the following configurations are common:
skip the initialisation phase of the logging module, assuming that it is performed elsewhere.
allows you to decide whether Log::Log4perl (when set to a false value) or Log::Log4perl::Tiny (when set to a true value) should be used.
If you're using standard Log::Log4perl, then you have two alternatives to pass a configuration:
via a configuration file, using the config_file option:
config_file
logger: log4perl log4perl: config_file: log4perl.conf
via a straight configuration text, using the config option:
config
logger: log4perl log4perl: config: | log4perl.rootLogger = DEBUG, LOG1 log4perl.appender.LOG1 = Log::Log4perl::Appender::File log4perl.appender.LOG1.filename = /var/log/mylog.log log4perl.appender.LOG1.mode = append log4perl.appender.LOG1.layout = Log::Log4perl::Layout::PatternLayout log4perl.appender.LOG1.layout.ConversionPattern = %d %p %m %n
If all you have is Log::Log4perl::Tiny, you can set some parameters:
the log level
level
logger: log4perl log4perl: tiny: 1 level: INFO
the log format (aliased to layout as well)
format
layout
logger: log4perl log4perl: tiny: 1 format: [%p] %m%n
All examples below assume that you have your Log::Log4perl initialisation stuff inside a file called log4perl.conf, e.g. something along the following lines:
log4perl.logger = INFO, Screen log4perl.appender.Screen = Log::Log4perl::Appender::Screen log4perl.appender.Screen.stderr = 1 log4perl.appender.Screen.stdout = 0 log4perl.appender.Screen.layout = Log::Log4perl::Layout::PatternLayout log4perl.appender.Screen.layout.ConversionPattern = [%d] [%-5p] %m%n
The above initialisation text is actually what you get by default.
In this case you'll probably want to let the module handle the initialisation and forget about Log::Log4perl in your code. In the Dancer configuration file:
# config.yml logger: log4perl log: info log4perl: config_file: log4perl.conf
In your code:
# somewhere... get '/please/warn' => sub { warning "ouch!"; # good ol' Dancer warning return ':-)'; };
If you want to use Log::Log4perl's stealth interface, chances are you also want to avoid a full configuration file and rely upon easy_init(). In this case, you will probably want to perform the initialisation by your own, so your configuration file will be bare bones:
easy_init()
# config.yml logger: log4perl log: info log4perl: no_init: 1
and your code will contain all the meat:
use Log::Log4perl qw( :easy ); Log::Log4perl->easy_init($INFO); get '/please/warn' => sub { WARN 'ouch!'; # Log::Log4perl way of warning return ';-)'; };
Whatever the method you use to initialise the logger (but take care to initialise it once and only once, see Log::Log4perl), you can always use both Dancer and Log::Log4perl functions:
use Log::Log4perl qw( :easy ); get '/please/warn/2/times' => sub { warning 'ouch!'; # Dancer style WARN 'OUCH!'; # Log::Log4perl style return ':-D'; };
If you don't like either functional interface, and prefer to stick to Log::Log4perl's object-oriented interface to avoid collisions in function names:
use Log::Log4perl (); get '/please/warn/2/times' => sub { get_logger()->warn('ouch!'); # Log::Log4perl, OO way return 'B-)'; };
Well, you get the idea... just peruse Log::Log4perl documentation for more!
If you prefer to use Log::Log4perl::Tiny you can put the relevant options directly inside the configuration file:
# config.yml logger: log4perl log: debug log4perl: tiny: 1 level: DEBUG format: [%p] %m%n
At this point, you can import the relevant methods in your code and use them as you would with Log::Log4perl:
use Log::Log4perl::Tiny qw( :easy ); get '/please/warn' => sub { WARN 'ouch!'; # Log::Log4perl(::Tiny) way of warning # you can also use Dancer's warning here... warning 'OUCH!'; return ';-)'; };
As an alternative to the previous example, you can also limit the configuration file to a minimum:
# config.yml logger: log4perl log: info log4perl: tiny: 1
and initialise the logging library inside the code:
use Log::Log4perl::Tiny qw( :easy ); Log::Log4perl->easy_init($INFO); get '/please/warn' => sub { WARN 'ouch!'; # Log::Log4perl(::Tiny) way of warning # you can also use Dancer's warning here... warning 'OUCH!'; return ';-)'; };
If you find a bug, have a comment or (constructive) criticism you have different options:
just write to the "AUTHOR"
open a bug request on the relevant RT queue at https://rt.cpan.org/Public/Dist/Display.html?Name=Dancer-Logger-Log4perl
open an issue or propose a patch on GitHub at https://github.com/polettix/Dancer-Logger-Log4perl
To install Dancer::Logger::Log4perl, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Dancer::Logger::Log4perl
CPAN shell
perl -MCPAN -e shell install Dancer::Logger::Log4perl
For more information on module installation, please visit the detailed CPAN module installation guide.