Rack::CommonLogger forwards every request to an app given, and logs a line in the Apache common log format to the logger, or rack.errors by default.
Common Log Format: httpd.apache.org/docs/1.3/logs.html#common lilith.local - - [07/Aug/2006 23:58:02] "GET / HTTP/1.1" 500 -
%{%s - %s [%s] "%s %s%s %s" %d %s\n} %
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