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From Colm MacCarthaigh <c...@stdlib.net>
Subject htcacheadmin was: Re: [PATCH] fix incorrect 304's responses when cache is unwritable
Date Fri, 12 Aug 2005 08:07:04 GMT
On Thu, Aug 11, 2005 at 11:48:21PM -0700, Justin Erenkrantz wrote:
> Right.  I think Paul mentioned that we also need to fix up htcacheclean to
> remove the .vary subdirectories as well.  -- justin

Next time someone is commiting to htcacheclean; it's define's for
VARY_FORMAT_VERSION and DISK_FORMAT_VERSION are wrong. They should be 3,
and 4 respectively - as per mod_disk_cache.c. Right now they are 1 and
2.

I'm writing something else now, to help me debug cache edge cases, I'm
still seeing some misbehaviour that I need to track down, but I'm having
trouble re-creating vary caching. 

If the vary content is locally generated, it is saved as per content
location. And right now, I can't get it cache proxied vary content at
all. Though it doesn't help that I've hamfisting the mod_proxy code in
trunk to even compile.

Does anyone have a remote URI on some webserver somewhere that reliably
returns a Vary response that is cacheable?

That something else;  htcacheadmin 

Now that I'm running with an expanded cache, and trying to debug things
while I'm at it, I keep coming accross needing to do the same tasks, but
"find ./ -type f | xargs grep" just isn't a reliable way of tracking
down cache entities. So I've written htcacheadmin.

It's *extremely* useful for debugging, which is why I'm posting it now -
it's helped me a lot. It's useful for administrators too, but I'm not
sure if it's useful enough Vs confusing enough for support/

Anyway, right now it's got most of its functionality working, but it
only works for locally generated non-vary content. I'm going to add a
loop to allow it to work through the various key permutations for proxy
support, eg.

	ftp.heanet.ie/pub/heanet/100.txt?
	ftp.heanet.iehttp://ftp.heanet.ie/pub/heanet/100.txt?
	ftp.heanet.iehttp://ftp.heanet.ie:80/pub/heanet/100.txt?

to track down likely cache matches. Though I wonder is there a hope of
convinving anyone to change the cache key to something utterly
determinstic like;

	http://ftp.heanet.ie:80/pub/heanet/100.txt?

including the scheme will help me when I go to make caching work for
ftp, and the rest just helps make it reliably deterministic.

Anyway, other features I want to add including allowing the
administrator to extend the expiry of particular entities, and I think I
might split it's functionality so that it has one mode which locates
(and only locates) cache entities, and then another mode which does the
information retrieval taking a .header file as an argument (more useful
to admins since they can guarantee the output is for one instance only).

See attachment, feedback appreciated.

-- 
Colm MacCárthaigh                        Public Key: colm+pgp@stdlib.net

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