How to log slow HTTP responses

Question

How does one log slow HTTP responses? I'm using Lighttpd, but could switch to another webserver if necessary.

Apache can log response times, but not conditionally, it seems.

http://httpd.apache.org/docs/2.4/mod/mod_log_config.html

Apache Bench and httping are useful client-side for some general testing but aren't useful for long term logging.

Answer 1

Why not use the piped logs functionality to achieve this? You'll probably have to write your own shell script to write the "slow responses" to a separate file, but you're in complete control here.

See http://httpd.apache.org/docs/2.4/logs.html#piped