Apache mod_cache/mod_disk_cache...?

[Matt Wise]

Is anybody using mod_cache/mod_disk_cache with Puppet? I found a post talking about it here (http://paperairoplane.net/?p=380) and I tried to implement it .. but I found that nothing was being cached. Near as I can tell, Apache refuses to cache any URL that has a query-string attached to it:

(http://httpd.apache.org/docs/2.2/caching.html)

• If the URL included a query string (e.g. from a HTML form GET method) it will not be cached unless the response specifies an explicit expiration by including an "Expires:" header or the max-age or s-maxage directive of the "Cache-Control:" header, as per RFC2616 sections 13.9 and 13.2.1.

However, when you look at the mod_cache doc itself

(http://httpd.apache.org/docs/2.2/mod/mod_cache.html#cacheignorequerystring)

Ordinarily, requests with query string parameters are cached separately for each unique query string. This is according to RFC 2616/13.9 done only if an expiration time is specified. TheCacheIgnoreQueryString directive tells the cache to cache requests even if no expiration time is specified, and to reply with a cached reply even if the query string differs. From a caching point of view the request is treated as if having no query string when this directive is enabled.

These two things seem at-odds with eachother. When I turn 'cacheignorequerystring' On in Apache, the caching starts to work ... but as I understand it, it menas that a request for /foo.sh?bar will cache and return the same result as /foo.sh?xyz ... thus making the query string completely ignored. However, if I leave it off, I get no caching at all because Puppet seems to make every single file request with a ? attached to it:

Jun 10 00:17:59.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadata/modules/zk/ssl/cacert.pem? HTTP/1.1" 200 330 "-" "-" 0/6260

Jun 10 00:17:59.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadata/modules/zk/ssl/zookeeper.XYZ.com.key? HTTP/1.1" 200 346 "-" "-" 0/4499

Jun 10 00:17:59.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadata/modules/stunnel/stunnel? HTTP/1.1" 200 328 "-" "-" 0/4703

Jun 10 00:18:00.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadatas/modules/zk/code?&recurse=true&links=manage&checksum_type=md5& HTTP/1.1" 200 660 "-" "-" 0/7805

Jun 10 00:18:02.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadata/modules/zk/upstart? HTTP/1.1" 200 323 "-" "-" 0/4843

Jun 10 00:18:03.000000 puppetmaster-20372704.cloud.XYZ.com apache: puppetmaster-20372704.cloud.XYZ.com:443 204.236.165.198 - - - puppet.XYZ.com:8140 "GET /production/file_metadatas/modules/prod_ve/certs?&recurse=true&links=manage&checksum_type=md5& HTTP/1.1" 200 2765 "-" "-" 0/16361

If Puppet did not have the ? at the end of the URL, I think that Apache would cache the requests... but obviously this still prevents me from caching the catalogs. Any thoughts?

—Matt