/ 
Log-Abstraction-0.41
/ Log::Abstraction::Backend

NAME

Log::Abstraction::Backend - base class of the Log::Abstraction backends

VERSION

0.40

DESCRIPTION

For use by Log::Abstraction only. Log::Abstraction->new() builds one object of a Log::Abstraction::Backend::* class for each place a message goes to (a file, an array, syslog ...), and each message is passed to every one of them. The configuration given to new() is not changed.

The backends are:

Log::Abstraction::Backend::Array        array, or logger => \@array
Log::Abstraction::Backend::Code         logger => \&code
Log::Abstraction::Backend::Fd           fd
Log::Abstraction::Backend::File         file, or logger => $path
Log::Abstraction::Backend::Journald     journald
Log::Abstraction::Backend::LogAny       log_any, or a Log::Any logger
Log::Abstraction::Backend::LogDispatch  log_dispatch, or a Log::Dispatch object
Log::Abstraction::Backend::Object       any other object as the logger
Log::Abstraction::Backend::Sendmail     sendmail
Log::Abstraction::Backend::Syslog       syslog

METHODS

new

my $backend = Log::Abstraction::Backend::File->new(
    file   => $path,
    level  => 4,        # numeric threshold, or undef for none
    format => $format,  # or undef
);

Stores its arguments. They have already been checked by Log::Abstraction->new(); level is a syslog number (0-7).

API SPECIFICATION

Input

{
    level  => { type => 'integer', min => 0, max => 7, optional => 1 },
    format => { type => 'string', min => 1, optional => 1 },
    # and the destination, under the backend's own key (file, fd,
    # array, sendmail ...)
}

Output

{ type => 'object', isa => 'Log::Abstraction::Backend' }

wants

next unless $backend->wants($event);

True if the backend has no level of its own, or the message is at that level or more severe.

API SPECIFICATION

Input

{ event => { type => 'hashref', schema => { priority => { type => 'integer', min => 0, max => 7 } } } }

Output

{ type => 'boolean' }

text

my $message = $backend->text($event, $event->{text});

The message formatted with the backend's own format, if it has one, otherwise the default given.

API SPECIFICATION

Input

{
    event   => { type => 'hashref', schema => { render => { type => 'coderef' } } },
    default => { type => 'string' },
}

Output

{ type => 'string' }

emit

$backend->emit($logger, $event);

Sends a message, which has passed the logger's level, to the backend. $logger is the Log::Abstraction object. $event is a hash reference built by Log::Abstraction for each message:

level        the level name, e.g. 'warn'
priority     its syslog number (0-7)
message      the message, its parts joined and redacted
parts        the message's parts (an array reference)
fields       the structured fields (a hash reference), or undef
fields_text  the fields as key=value text, or undef
text         the message with fields_text appended
entry        the history entry (a list, as an array reference)
class, file, line, ctx   for CODE references
render       format a line: $event->{render}->($format), undef for
             the logger's format
write        write a line to a path (which it checks) or a handle:
             $event->{write}->($target, $line)
send_email, hold_email   send or keep for later an email:
             $event->{send_email}->(\%sendmail, $body)

The closures are how a backend uses Log::Abstraction's private methods. Subclasses must override this.

API SPECIFICATION

Input

{
    logger => { type => 'object', isa => 'Log::Abstraction' },
    event  => { type => 'hashref' },    # the keys above
}

Output

None.  The base class's emit() croaks "<class>: emit() is not
implemented"; a subclass's sends the message.  A failed delivery is
carped, not fatal; a configuration error (e.g. an invalid sendmail
host) still croaks.

AUTHOR

Nigel Horne njh@nigelhorne.com

SEE ALSO

Log::Abstraction

COPYRIGHT AND LICENSE

Copyright (C) 2025-2026 Nigel Horne

Usage is subject to the GPL2 licence terms. If you use it, please let me know.