Re: Offline use of apt-cacher

[Eduard Bloch <edi@gmx.de>]

#include <hallo.h>
* Anuradha Ratnaweera [Mon, Jan 23 2006, 06:24:08PM]:

> - Lazy online: we like apt-cacher to fetch a Packages/Release file
> only if it old as set by a timeout.  So if one runs apt-get update
> many times during a short period, only the first one will need to make
> a HEAD/GET request.  (Lazy online has one tricky case if Packages file
> does get update before timeout, but that can be handled neatly and
> transparently as we are online).

Fine... but don't you describe what is said in the comments in
apt-cacher.conf?

# apt-cacher can use different methods to decide whether package lists need to
# be updated,
# A) looking at the age of the cached files
# B) getting HTTP header from server and comparing that with cached data. This
# method is more reliable and avoids desynchronisation of data and index files
# but needs to transfer few bytes from the server every time somebody requests
# the files ("apt-get update")
# Set the following value to the maximum age (in hours) for method A or to 0
# for method B
expire_hours=0

So you basically want it to detect whether it's online and deliever the
old version if it's offline? That would be a bit uncomfortable in the
code because I would like to know up-front whether the file needs to be
refreshed or not. And how to detect the off-line status quick enough,
and not be confused with a timeout/slow server?

>   This mode is going to be very useful when:
>   - upgrading a large number of machines
>   - running a script which _needs_ to run apt-get update many times
> (and it can't be rewritten to do it otherwise)
> 
> - Offline: apt-cacher is totally offline.  Files (Packages/Release
> files as well as DEBs) are served if available, and returns 503 if not
> available.

As said bvefore, if you activate this mode manually, this should be an
easy feature to add on. How do you want to configure it?

Eduard.

-- 
Major Krantz: What if we take you with us, put you on trial.
Zathras: Zathras not of this time.  You take, Zathras die. You leave, Zathras
die. Either way, it is bad for Zathras.
                                                 -- Quotes from Babylon 5 --