Hi Daniel, On Sat, Nov 21, 2015 at 10:58 AM, Daniel Hlynskyi <[email protected]> wrote: > But when I run `nixos-rebuild` twice, I notice that tarball is not > downloaded second time. > > root# > NIX_PATH=nixos-config=/etc/nixos/configuration.nix:nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz > \ > root# nixos-rebuild dry-build > building the system configuration... > # -----> tarball is not downloaded second time <----------- > these derivations will be built: > /nix/store/h2sp5p9x3gzryiq57znqdzc3jrw3dlpa-nixos-help.drv > /nix/store/9gzsm78klcassgs9yvpmnd38naczndc1-system-path.drv > /nix/store/rflgcrmas917yzdihxd9kqbp8n27w2qj-dbus-conf.drv > > What kind of caching is this and what happens when upstream tarball changes?
I asked Eelco a similar question, and Nix will check the meta data of the file before any attempt to download it, if the meta data highlight that the file is unchanged on the server, then Nix will not re-download it. Your browser does the same thing to avoid re-downloading resources as long as it does not change on the server. -- Nicolas Pierron http://www.linkedin.com/in/nicolasbpierron - http://nbp.name/ _______________________________________________ nix-dev mailing list [email protected] http://lists.science.uu.nl/mailman/listinfo/nix-dev
