[Nix-dev] nixos-rebuild switch and downloading missing files

[Eelco Dolstra]

Wouter wrote:

> Maybe we should let the buildfarm (?) automatically distribute
> downloaded sources to http://nix.cs.uu.nl/dist/tarballs/.... and let it
> change the expressions.

The first part would be great but the second part very scary (letting the build
farm commit automatically in the Nixpkgs source...).

Maybe a nice approach would be for fetchurl to be expanded to look for tarballs
in a set of default URLs.  So if you have

  fetchurl {
    src = http://example.org/tarball.tar.bz2;
    md5 = HASH;
  }

it would first try to download from (say)
http://nix.cs.uu.nl/dist/tarballs/HASH-tarball.tar.bz2 and maybe some more
(configurable) locations.

Extra points for transparently downloading large files via Bittorrent ;-)

-- 
Eelco Dolstra | http://www.cs.uu.nl/~eelco