Log4r is a comprehensive and flexible logging library written in Ruby for use in Ruby programs. It features a hierarchical logging system of any number of levels, custom level names, logger inheritance, multiple output destinations, execution tracing, custom formatting, thread safteyness, XML and YAML configuration, and more.
Log4r is an adherent to the philosophy of logging using simple print statements. What Log4r adds to this philosophy is a flexible way of controlling the information being logged. Log information can be sent to any kind of destination and with varying degrees of importance. Log4r is designed so that logging statements can remain in production code with almost no extra computational cost.
Log4r intends to be easy to use and configure, no matter the complexity.