RE: [squid-users] ICAP service adaptation with service sets

> > From: Amos Jeffries [mailto:squid3_at_treenet.co.nz]

> On 21/04/2012 5:53 a.m., Francis Fauteux wrote:

> > * Modify the RESPMOD server to inject an "X-Next-Services: new_respmod_service<n>"
> > header to activate the new service, and inject an "X-Next-Services: "
> > header to deactivate the new service.

> Um, "activate" is a tricky word here. X-Next-Service tells Squid to use
> the named service(s) on the currently processing request. It does not do
> anything for other requests which "activate" implies.

My apologies, I did mean "activate" and "deactivate" on a per-request basis,
not for other requests. I guess the word "activate" is misleading since all
services (A, B, C,...) in the plan are 'activated' by default until X-Next-Services
tells Squid otherwise.

> > * Does the RESPMOD server need to inject an "X-Next-Services: "
> > header with no value to deactivate the new service, or will it be bypassed
> > by default?

> The header is per-request. Squid starts off with a plan for doing A then
> B then C filters from the squid.conf settings. X-Next-Services is an
> explicit instruction to erase that plan and replace it with a new set
> starting immediately.
> With that I believe empty header to mean discard the old set and finish
> adaptation immediately.

Thank you, this answers my question.

> > * Each service has a farm of server processes for failover in case of error, but it seems the "X-Next-Services: new_respmod_server<n>" header will route to a specific service, not a service set. Is there a way to route requests to a service set or, if not, to provide failover for the new service?

> Hmm. I think you just have it send back the service set name
> "X-Next-Services: new_respmod_set". I'm not very familiar with the ICAP
> internal specifics though.

I'll have to prototype our solution to see whether this works.

> > * We are using squid version 3.1.14, for which we cannot find the
> > release notes (3.1.15 is the earliest version we found).
> > Can you confirm that 3.1.14 supports service adaptation ?

> http://www.squid-cache.org/Versions/v3/3.1/squid-3.1.14-RELEASENOTES.html
> ftp://ftp.squid-cache.org/pub/archive/3.1/
> No ICAP related changes from the current latest series release notes though.

Apologies, I was looking at http://squidcache.cybermirror.org/squid/
(returned by a Google search), Which starts at 3.1.15.

- Francis
Received on Mon Apr 23 2012 - 12:46:51 MDT