Bug#763021: di-netboot-assistant: support for use in a build environment

[Matt Taggart <taggart@debian.org>]

Package: di-netboot-assistant
Version: 0.38a
Severity: wishlist

Related to #503359 which added support for running d-n-a as a 
non-privileged user, I would like support for running as part of a build 
environment that creates a root of d-i images to be used on a tftp server, 
usb stick, etc. My goal is to have this build environment in a git repo and 
have a user clone it on their system and do a build.

dkg's original patch using a DI_NETBOOT_ASSISTANT_CONFIG environment 
variable was actually better in that regard since one could easily override 
it in build scripts. But I do also like the way #503359 was implemented to 
look for a ~/.di-netboot-assistant.

But the other issue I am running into when trying to create this build 
environment is absolute paths for things like DL_CACHE and STATUS_LIB. 
Since I can't know what directory the build will be in, I need some way for 
these to be relative (or have to resort to complicated hacks).

So how about this?
1) a way to override the "root" of d-n-a variables
* if an environment variable is set (DNA_ROOT?), use that as the root for 
other variables, otherwise check for ~/.di-netboot-assistant and then 
/etc/di-netboot-assistant
* if the variable was set or ~/.di-netboot-assistant was found have the 
following change to be relative to the root
  DISOURCELIST, DL_CACHE, STATUS_LIB, and possibly TEMPLATES, and TFTP_ROOT

2) a way to override just the config, like dkg's DI_NETBOOT_ASSISTANT_CONFIG
 and that would allow for other overrides in addition to the above

Thanks,

-- 
Matt Taggart
taggart@debian.org