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Log::ger - A lightweight, flexible logging framework


version 0.023


In your module (producer):

 package Foo;
 use Log::ger; # will import some logging methods e.g. log_warn, log_error

 sub foo {
     # produce some logs
     log_error "an error occurred: %03d - %s", $errcode, $errmsg;
     log_debug "http response: %s", $http; # automatic dumping of data

In your application (consumer/listener):

 use Foo;
 use Log::ger::Output 'Screen';



Log::ger is yet another logging framework with the following features:

  • Separation of producers and consumers/listeners

    Like Log::Any, this offers a very easy way for modules to produce some logs without having to configure anything. Configuring output, level, etc can be done in the application as log consumers/listeners. To read more about this, see the documentation of Log::Any or Log::ger::Manual (but nevertheless see Log::ger::Manual on why you might prefer Log::ger to Log::Any).

  • Lightweight and fast

    Slim distribution. No non-core dependencies, extra functionalities are provided in separate distributions to be pulled as needed.

    Low startup overhead. Only ~0.5-1ms. For comparison, strict ~0.2-0.5ms, warnings ~2ms, Log::Any 0.15 ~2-3ms, Log::Any 1.049 ~8-10ms, Log::Log4perl ~35ms. This is measured on a 2014-2015 PC and before doing any output configuration. For more benchmarks, see Bencher::Scenarios::LogGer or try yourself e.g. with bencher-code:

     % bencher-code 'use Log::ger' 'use Log::Any' --startup

    Fast. Low null-/stealth-logging overhead, about 1.5x faster than Log::Any, 3x faster than Log4perl, and 5x faster than Log::Fast.

    Conditional compilation. There is a plugin to optimize away unneeded logging statements, like assertion/conditional compilation, so they have zero runtime performance cost. See Log::ger::Plugin::OptAway.

    Being lightweight means the module can be used more universally, from CLI to long-running daemons to inside routines with tight loops.

  • Flexible

    Customizable levels and routine/method names. Can be used in a procedural or OO style. Log::ger can mimic the interface of Log::Any, Log::Contextual, Log::Log4perl, or some other popular logging frameworks, to ease migration or adjust with your personal style.

    Per-package settings. Each importer package can use its own format/layout, output. For example, some modules that are migrated from Log::Any uses Log::Any-style logging, while another uses native Log::ger style, and yet some other uses block formatting like Log::Contextual. This eases code migration and teamwork. Each module author can preserve her own logging style, if wanted, and all the modules still use the same framework.

    Dynamic. Outputs and levels can be changed anytime during run-time and logging routines will be updated automatically. This is useful in situation like a long-running server application: you can turn on tracing logs temporarily to debug problems, then turn them off again, without restarting your server.

    Interoperability. There are modules to interop with Log::Any, either consume Log::Any logs (see Log::Any::Adapter::LogGer) or produce logs to be consumed by Log::Any (see Log::ger::Output::LogAny).

    Many output modules and plugins. See Log::ger::Output::*, Log::ger::Format::*, Log::ger::Layout::*, Log::ger::Plugin::*. Writing an output module in Log::ger is easier than writing a Log::Any::Adapter::*.

For more documentation, start with Log::ger::Manual.


Some other popular logging frameworks: Log::Any, Log::Contextual, Log::Log4perl, Log::Dispatch, Log::Dispatchouli.


perlancar <perlancar@cpan.org>


This software is copyright (c) 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.