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package Log::ger::Manual::Tutorial::100_WhatIsLogging;
# AUTHORITY
# DATE
our $DIST = 'Log-ger-Manual'; # DIST
# VERSION
1;
# ABSTRACT: What is logging? Why logging? Logging vs ...
__END__
HideShow 78 lines of Pod
=pod
=encoding UTF-8
=head1 NAME
Log::ger::Manual::Tutorial::100_WhatIsLogging - What is logging? Why logging? Logging vs ...
=head1 VERSION
version 0.040.000
=head1 DESCRIPTION
=over
=back
=head1 WHAT IS LOGGING?
Logging is recording information during run-time. You can log any kind of
information for whatever purposes. Logging is most often used for debugging; you
can dump internal data structures, record warn/die message along with their
stack trace, or mark entering/leaving subroutines to trace the flow of program
execution. Logging can also be used to show the progress of a long-running
activity, to give users feedback so they know what's going on. Other uses of
logging include: auditing, accounting, security monitoring, source code
documentation, and so on.
To start logging with L<Log::ger>, all you have to do is C<use Log::ger> (or
C<require> I<and> C<import>) then start peppering logging statements. For
example:
 use Log::ger;
 sub process_user {
     log_trace("Entering process_user(%s)", \@_);
     ...
     log_trace("Leaving process_user(), result=%s", $res);
     return $res;
 }
 log_trace("Starting program");
 for my $user (@ARGV) {
     log_info("Processing user %s", $user);
     process_user($user);
 }
 log_trace("Ending program");
=head1 WHY LOGGING? LOGGING VS ...
Compared to using a debugger (with standard features like single-stepping,
breakpoints, watchpoints, etc), logging can help diagnose problems while you run
an application normally in production environment, as opposed to having to stop
a program and run it under the debugger. Of course, a proper debugger has its
strengths too.
Compared to peppering "print" statements all over your program, logging using a
framework brings the flexibility of turning on/off the statements according to
the notion of level/severity (or other criteria), and redirecting where the log
messages should go. On the other hand, "print" statement is simpler and does not
require extra module/framework.
=head1 AUTHOR
perlancar <perlancar@cpan.org>
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2022, 2020, 2019, 2018, 2017 by perlancar <perlancar@cpan.org>.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut