NAME

Log::ger::Manual::Tips - Tips when using Log::ger

VERSION

version 0.028.000

AVOIDING MULTIPLE REINITS

This should not matter unless you need to load a lot of plugins (and/or outputs, formatters, layouters, since these are all plugins too) *and* you have lots of modules in your applications that use logging *and* you have loaded those modules before initializing logging. And even then it should still be just a bit more overhead. But here it goes.

When you use Log::ger in a package, e.g.:

 package MyApp;
 use Log::ger;

then MyApp is added to the list of package targets. The list is consulted whenever we need to reinitialize all targets, i.e. reinstall logging routines for those targets.

Since by this time we have not added any outputs, then what Log::ger does is just install a no-op subroutine log_fatal(), log_error(), and so on to the target MyApp. When user calls log_fatal() inside this package, the output will go nowhere.

Let's say you also log in another package:

 package MyApp::Component1;
 use Log::ger;

the same thing will happen: MyApp::Component will have no-op logging routines.

Now let's say in your main application, you do this:

 use MyApp;
 use MyApp::Component1;
 use Log::ger::Output 'Screen';

the use Log::ger::Output 'OUTPUTNAME' line will install some hooks from Log::ger::Output::OUTPUTNAME to the list of hooks, then reinitializes all existing targets. In this case, the Screen output will install a hook in the create_log_routine phase that produces logger routines that prints to screen. When reinitializing, Log::ger will reinstall these logger routines to the MyApp and MyApp::Component1 namespaces. So when later user calls log_fatal() in the MyApp or MyApp::Component1 package, the log message will be printed to screen.

Suppose later a use Log::ger::Output 'File' statement is issued. The reinitialization process will change all logging routines in all targets to print to file instead. Logging is fast in Log::ger because Log::ger installs a customized logging routine on each target, but as a consequence reinitialization can take more time when there are lots of targets. This will become even slower if you load lots of plugins in your main application:

For each use Log::ger::Output or use Log::ger::Plugin or use Log::ger::Format statement, a reinit will happen to potentially many targets. Note that unless you have thousands of targets, all those reinits will still happen in under one second. But to avoid reinit, you can either load Log::ger plugins before adding lots of targets:

 use Log::ger::Output 'Screen';
 use Log::ger::Plugin 'Plugin1';
 use Log::ger::Plugin 'Plugin2';
 use Log::ger::Plugin 'Plugin3';
 use Log::ger::Plugin 'Plugin4';
 use Log::ger::Format 'Format1', {arg=>'value', ...};
 use MyApp;
 use MyApp::Component1;
 use MyApp::Component2;
 use MyApp::Component3;
 use MyApp::Component4;
 use MyApp::Component5;

or (the uglier way) tells the statements (but the last one) to not reinit:

 use MyApp;
 use MyApp::Component1;
 use MyApp::Component2;
 use MyApp::Component3;
 use MyApp::Component4;
 use MyApp::Component5;
 use Log::ger::Output {name=>'Screen', reinit=>0};
 use Log::ger::Plugin {name=>'Plugin1', reinit=>0};
 use Log::ger::Plugin {name=>'Plugin2', reinit=>0};
 use Log::ger::Plugin {name=>'Plugin3', reinit=>0};
 use Log::ger::Plugin {name=>'Plugin4', reinit=>0};
 use Log::ger::Format {name=>'Format1', conf=>{arg=>'value', ...}, reinit=>1}; # or just do not specify reinit, which defaults to 1

AUTHOR

perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019, 2018, 2017 by 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.