Provided by: liblog-any-perl_1.705-1_all 
NAME
Log::Any::Proxy - Log::Any generator proxy object
VERSION
version 1.705
SYNOPSIS
# prefix log messages
use Log::Any '$log', prefix => 'MyApp: ';
# transform log messages
use Log::Any '$log', filter => \&myfilter;
# format with String::Flogger instead of the default
use String::Flogger;
use Log::Any '$log', formatter => sub {
my ($cat, $lvl, @args) = @_;
String::Flogger::flog( @args );
};
# create a clone with different attributes
my $bar_log = $log->clone( prefix => 'bar: ' );
DESCRIPTION
Log::Any::Proxy objects are what modules use to produce log messages. They construct
messages and pass them along to a configured adapter.
ATTRIBUTES
adapter
A Log::Any::Adapter object to receive any messages logged. This is generated by Log::Any
and can not be overridden.
category
The category name of the proxy. If not provided, Log::Any will set it equal to the
calling when the proxy is constructed.
filter
A code reference to transform messages before passing them to a Log::Any::Adapter. It
gets three arguments: a category, a numeric level and a string. It should return a string
to be logged.
sub {
my ($cat, $lvl, $msg) = @_;
return "[$lvl] $msg";
}
If the return value is undef or the empty string, no message will be logged. Otherwise,
the return value is passed to the logging adapter.
Numeric levels range from 0 (emergency) to 8 (trace). Constant functions for these levels
are available from Log::Any::Adapter::Util.
Configuring a filter disables structured logging, even if the configured adapter supports
it.
formatter
A code reference to format messages given to the *f methods ("tracef", "debugf", "infof",
etc..)
It get three or more arguments: a category, a numeric level and the list of arguments
passsed to the *f method. It should return a string to be logged.
sub {
my ($cat, $lvl, $format, @args) = @_;
return sprintf($format, @args);
}
The default formatter does the following:
prefix
If defined, this string will be prepended to all messages. It will not include a trailing
space, so add that yourself if you want. This is less flexible/powerful than "filter",
but avoids an extra function call.
USAGE
Simple logging
Your library can do simple logging using logging methods corresponding to the log levels
(or aliases):
Pass a string to be logged. Do not include a newline.
$log->info("Got some new for you.");
The log string will be transformed via the "filter" attribute (if any) and the "prefix"
(if any) will be prepended. Returns the transformed log string.
NOTE: While you are encouraged to pass a single string to be logged, if multiple arguments
are passed, they are concatenated with a space character into a single string before
processing. This ensures consistency across adapters, some of which may support multiple
arguments to their logging functions (and which concatenate in different ways) and some of
which do not.
Advanced logging
Your library can do advanced logging using logging methods corresponding to the log levels
(or aliases), but with an "f" appended:
When these methods are called, the adapter is first checked to see if it is logging at
that level. If not, the method returns without logging.
Next, arguments are transformed to a message string via the "formatter" attribute.
The default formatter first checks if the first log argument is a code reference. If so,
it will executed and the result used as the formatted message. Otherwise, the formatter
acts like "sprintf" with some helpful formatting.
Finally, the message string is logged via the simple logging functions, which can
transform or prefix as described above. The transformed log string is then returned.
Numeric levels range from 0 (emergency) to 8 (trace). Constant functions for these levels
are available from Log::Any::Adapter::Util.
Logging Structured Data
If you have data in addition to the text you want to log, you can specify a hashref after
your string. If the configured adapter supports structured data, it will receive the
hashref as-is, otherwise it will be converted to a string using Data::Dumper and will be
appended to your text.
TIPS
UTF-8 in Data Structures
If you have high-bit characters in a data structure being passed to a log method, Log::Any
will output that data structure with the high-bit characters encoded as "\x{###}", Perl's
escape sequence for high-bit characters. This is because the Data::Dumper module escapes
those characters.
use utf8;
use Log::Any qw( $log );
my @data = ( "Привет мир" ); # Hello, World!
$log->infof("Got: %s", \@data);
# Got: ["\x{41f}\x{440}\x{438}\x{432}\x{435}\x{442} \x{43c}\x{438}\x{440}"]
If you want to instead display the actual characters in your log file or terminal, you can
use the Data::Dumper::AutoEncode module. To wire this up into Log::Any, you must pass a
custom "formatter" sub:
use utf8;
use Data::Dumper::AutoEncode;
sub log_formatter {
my ( $category, $level, $format, @params ) = @_;
# Run references through Data::Dumper::AutoEncode
@params = map { ref $_ ? eDumper( $_ ) : $_ } @params;
return sprintf $format, @params;
}
use Log::Any '$log', formatter => \&log_formatter;
This formatter changes the output to:
Got: $VAR1 = [
'Привет мир'
];
Thanks to @denis-it <https://github.com/denis-it> for this tip!
AUTHORS
• Jonathan Swartz <swartz@pobox.com>
• David Golden <dagolden@cpan.org>
• Doug Bell <preaction@cpan.org>
• Daniel Pittman <daniel@rimspace.net>
• Stephen Thirlwall <sdt@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2017 by Jonathan Swartz, David Golden, and Doug Bell.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.