Re: mod_perl output filter and mod_proxy, mod_cache

Hi Tim,

If you are after caching the responses, maybe an easier solution would
be to use a reverse proxy - like Varnish?

You would be then in complete control over the incoming and outgoing
headers and could cache responses based on the url / inject Expires
headers so browsers could cache them too etc.

Cheers,
Alex


On 14/07/11 11:39, Tim Watts wrote:
> On 14/07/11 11:16, André Warnier wrote:
>
> Hi Andre,
>
> Thanks for the quick reply :)
>
>> (That would probably be difficult, inefficient or both)
>>
>> Assuming that what you say about Tomcat is true (I don't know, and it
>> may be worth asking this on the Tomcat list), I can think of another way
>> to achieve what you seem to want :
>> if you can distinguish, from the request URL (or any other request
>> property), the requests that are for invariant things, then you could
>> arrange to /not/ proxy these requests to Tomcat, and serve them directly
>> from Apache httpd.
>
> Indeed that is a good idea. We are doing that for new projects for css
> and js files (apache does not proxy certain paths and picks these up
> from the local filesystem).
>
> We can't do that for the 100 odd legacy servers as no-one has time o
> delve into the java/JSP code. I need to do something "outside" of
> tomcat where possible. Just to explain, each web server is a paid-for
> project - and when it's done, it sits there for 5+ years.
>
> Only I have the time/inclination to fix this as it's killing my VMWare
> infrastructure. Because the sites are all fronted by apache in a
> similar way, one solution is likely to apply to most of the sites.
>
> I would also add that most of the sites are "dynamically" driven
> pages, even involving MySQL querying, but once launched, the data
> remains fairly static - eg GET X will always resolve to reponse Y.
>
> I'm planning a small seminar on the value of Cache-Control for my dev
> colleagues so they can stop making this mistake ;-> But that still
> leaves a lot of "done" projects to fix.
>
>> Which proxying method exactly are you using between Apache and Tomcat ?
>> (if you are using mod_proxy, then you are either using mod_proxy_http or
>> mod_proxy_ajp; you could also consider using mod_jk).
>
> mod_proxy_http specifically.
>
> mod_jk looks interesting for new projects (we have local tomcats for
> those now) - I think it may be a non-starter for old stuff as trying
> to retro fit it may not be so simple (our older tomcat servers are in
> a remote farm on their own machines hence the use of mod_proxy_http).
>
>> Also, what are the versions of Apache and Tomcat that you are using ?
>>
>
> Apache 2.2 (various sub versions) and both tomcat 5.5 and tomcat 6
> (but all on remote machines listening on TCP sockets).
>
> I think for this problem, I have to treat tomcat as a little, rather
> inefficient, black box and try to fixup on the apache front ends,
> hence the direction of my original idea...
>
> Cheers,
>
> Tim
>