Re: CARP improvements

On 31/07/11 07:26, Kinkie wrote:
> Hi all,
> attached is a first revision of the patch for review. I've build-
> and run- tested it.
> Only issue not fully investigated is that when an user login is
> specified in the request, carpSelectParent is not invoked at all. This
> is however external from the carp code itself; only effect it has is
> that the "login" carp key selector is actually useless.
>

When login is in headers rather than URL you may need to use:

   if (tp->options.carp_key.login) {
       if (request->login && *request->login) {
           key.append(request->login);
       }
#if USE_AUTH
         else if (request->auth_user_request) {
           key.append(request->auth_user_request->username());
       }
#endif
           key.append('@');
   }

I'm not sure if you want auth auth_user_request->type() and public
tokens embeded in the header case as well.

> On Mon, Jul 18, 2011 at 2:01 PM, Amos Jeffries<squid3_at_treenet.co.nz> wrote:
>> On 18/07/11 22:27, Kinkie wrote:
>>>
>>> Hi guys,
>>> I would like some input on how to best tweak CARP with a very small
>>> change:
>>> as it is now the canonical URL is used to define the hash for next parent.
>>> It is very efficient - even too much.
>>>
>>> I'd like to add a variant to it so that only the host part of the URL
>>> is used as initial key for the hashing.
>>> This will decrease the effectiveness of the balancing, but make it
>>> easier to cope with some websites which do not like it when requests
>>> travel across different routes.
>>>
>>> There are three ways I can think of to address this:
>>> - change the way CARP works - it's an one-liner
>>> - new global setting
>>> - new carp option (e.g. hcarp or host-carp)
>>>
>>> What do you think is the best way to implement this?
>>
>> I think a slightly more flexible way would be a carp-key=XX parameter. Where
>> one can potentially set (scheme,host,port,path,params) tags. That would
>> allow a bit more tuning of the mask.

src/cache_cf.cc:
  * Can you use strncasecmp instead of casecmp?
    so the parser can work on const char* and avoid strdup() and \0 writes

src/carp.cc:
  * s/"cornercases"/"corner cases"
  * also a bit wrong, this code does not cover _all_ corner cases as
canonical. Things like unknown method and unknown protocols will use the
else condition. Which in fact defaults to the custom key.
  At least the docs needs to say "corner cases should use canonical URL"

  Can you explain why that is even needed though? Both CONNECT and URN
cases have all keys with known values. Albeit some values are "".

Amos

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