Log::Any::Proxy(3pm) User Contributed Perl Documentation Log::Any::Proxy(3pm)
NAME
Log::Any::Proxy - Log::Any generator proxy object
VERSION
version 1.713
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.
context
Logging context data hashref. All the key/value pairs added to this
hash will be printed with every log message.
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.
perl v5.36.0 2023-01-07 Log::Any::Proxy(3pm)
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