Hi, On Wed, Jun 26, 2013 at 11:20:49AM +0200, [email protected] wrote: > Hi folks, > > i've a question regarding "use_backend" and how conditions are processed. > > My Example: > > > ---- > > frontend http_in_01 > > bind 1.2.3.4:80 > > log global > option httplog > > capture request header Host len 32 > capture request header User-Agent len 200 > > reqidel ^X-Forwarded-For:.* > option forwardfor > > option http-server-close > > > acl is_domain_abc.de hdr_dom(host) -i abc.de > > acl is_regex_matching url_reg ..... > acl is_regex_matching url_reg ..... > acl is_regex_matching url_reg .... > acl is_regex_matching url_reg .... > acl is_regex_matching url_reg .... > . > . > ... another 10000 lines is_regex_matching > > > > use_backend webfarm01 if is_domain_abc.de !is_regex_matching > > --- > > > If the first condition in "use_backend" line is NOT met ( the domain in the > HTTP-Request is not abc.de ), is the processing for this "use_backend" > line stopped or is the second condition ( the > heavy regex acl) processed anyway ? (and unnecessarily* *consume > ressources )
no, it will not be processed. The ACLs evaluation stop at the earliest possible time, which is : - when one ACL returns false in an AND condition - when one ACL expression returns true in an OR condition They are always evaluated from left to right, which is why it's important to put the cheapest ones and the least likely ones on the left. In your case it's perfect. Also, note that you can optimize your ACL by passing multiple patterns on the same line. It will save some URL fetches since the regex patterns will be applied in sequence to the same URL. Regards, Willy
