Logstash - transport and process your logs, events, or other data

Free and open log management

Request log analyzer's purpose is to find out how your web application is being used, how it performs and to focus your optimization efforts. This tool will parse all requests in the application's log file and aggregate the information. Once it is finished parsing the log file(s), it will show the requests that take op most server time using various metrics. It can also insert all parsed request information into a database so you can roll your own analysis. It supports Rails-, Merb- and Rack-based applications logs, Apache and Amazon S3 access logs and MySQL slow query logs out of the box, but file formats of other applications can easily be supported by supplying an easy to write log file format definition.

Centralized logging for rails apps using MongoDB. The idea and the core code is from http://github.com/peburrows/central_logger

Mountable Rails Engine for viewing paginated logs from a browser

A tail(1)-like utility for nginx log files. It supports parsing, filtering and formatting individual log lines.

Indy is a log archaeology library that treats logs like data structures. Search standard or custom log formats by field and/or time.

this is gem is useful to check the log file data in browser