Re: [gentoo-council] Comparison of GLEP 54 and 'live ebuild' proposal

[Luca Barbato <lu_zero@gentoo.org>]

Roy Bamford wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> On 2009.03.09 22:47, Thomas Anderson wrote:
>> Hi,
>>
>>     Attached is my comparison of the two proposals for live sources.
>>     Sorry about getting it out late, I had to get ahold of a number 
>> of
>>     people to finish writing it up.
>>
>> Cheers,
>> Thomas
>> -- 
>> ---------
>> Thomas Anderson
>> Gentoo Developer
>> /////////
>> Areas of responsibility:
>> AMD64, Secretary to the Gentoo Council
>> ---------
>>
>>
> 
> - ------quoted attachment "glep54comp.txt"------
> [snip]
>>     One important issue is what happens in the following
>>     scenario:
>>     	1) world update starts at 20090301@2200hrs.
>> 	2) this particular update involves 100 packages so it takes
>> quite
>> 	along time
>> 	3) The _live package is not reached until 20090302 at 1AM.
>>
>>      Is the package installed as 20090301 or 20090302?
>>
> [snip]
> 
> Thomas,
> 
> Live has to expand to the date when the sources were fetched, otherwise 
> its not 'live' by definition.
> As an illustration, I install KDE 4.2 on my 25MHz 486DX with 64Mb RAM.
> During the time it takes to build, 'live' is likely to have changed 
> several times.

It isn't exactly a problem (more will follow)

> 
> How do you handle prefetching of sources, or do you forbid 
> prefetching ?

live template ebuild require supporting src_fetch among the other stuff. 
Keep in mind that once you get  an ebuild from the template you can 
use&reuse it as a normal ebuild (so it works like the mythtv "not so 
live" ebuilds using svn on fixed revision)

> Live infers you fetch the sources at the time you need to build them 
> and do the live expansion at that time. Without that you don't know how 
> old your live version is.
> 
> live can change several times a day. With only one day resolution, how 
> do you handle that?

What is in the draft you can find on 
http://dev.gentoo.org/~lu_zero/glep/liveebuild.rst

"
Resolution and Version Comparison
---------------------------------

At resolution the live keyword is substituted with a timestamp in the 
form of
iso date (``YYYYMMDDhhmm``) and the version comparison follows the normal
version comparison rules.
"

Once you trigger the template -> ebuild generation you are working with 
a snapshot for all what concerns portage.

So once you start you are set.

lu

-- 

Luca Barbato
Gentoo Council Member
Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero