+ '"$http_user_agent" "$http_x_forwarded_for"';
+ log_format piwik
+ '{"ip": "$remote_addr",'
+ '"host": "$host",'
+ '"path": "$request_uri",'
+ '"status": "$status",'
+ '"referrer": "$http_referer",'
+ '"user_agent": "$http_user_agent",'
+ '"length": $bytes_sent,'
+ '"generation_time_milli": $request_time,'
+ '"date": "$time_iso8601"}';