nxLogging

This lightweight and open source framework provides logging for Delphi. It is full featured, supports multiple Loggers, Appenders and Formaters, but comes in a single file "nxLogging.pas". You can use it free for both, private and commercial applications.

Target compilers are from Delphi 2010 to Delphi X Seattle and Berlin, it is cross plattform, for Firemonkey and VCL.

You can use file logging in various strategies (plain, rolling file appender, ...) and remote logging is also supported. The framework can send log messages immediately to log servers, a central database for all your logmessages from all your installations.

There is also a free tool "nxTail" for live viewing logs. This can tail your log files and can be connected to log servers, to show all logs from all sources.