# To build and use it:
# nix-build docker-nix.nix -A hydraServer  && docker load < result && docker run -it nix bash
# In the container:
# nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgs
# nix-channel --update # and this fails



{pkgs ? import <nixpkgs> {}}:

let
    nixInit = ''
      mkdir tmp
      mkdir root
      echo "root:x:0:0::/root:/bin/bash" >> etc/passwd
      echo "nixbld:x:30000:nixbld1,nixbld2,nixbld3,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9,nixbld10,nixbld11,nixbld12,nixbld13,nixbld14,nixbld15,nixbld16,nixbld17,nixbld18,nixbld19,nixbld20,nixbld21,nixbld22,nixbld23,nixbld24,nixbld25,nixbld26,nixbld27,nixbld28,nixbld29,nixbld30" >> etc/group
      for i in $(seq 1 30); do echo "nixbld$i:x:$((30000 + $i)):30000:::" >> etc/passwd; done \
    '';
in
{
hydraServer = pkgs.dockerTools.buildImage rec {
    name = "nix";
    contents = [
      pkgs.coreutils
      # debug
      pkgs.nix pkgs.bash-completion pkgs.ncurses pkgs.bashInteractive
      pkgs.netcat pkgs.curlFull
      # pkgs.emacs25-nox
    ];
    extraCommands = ''
       # There is a bug in the docker builder
      chmod a+w ../layer
      # Should be move to docker build expression. This is used resolv
      # dns names from hosts file.
      chmod 0750 etc
      echo 'hosts:     files dns' > etc/nsswitch.conf

      mkdir -p etc/ssl/certs
      ln -s ${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt etc/ssl/certs/ca-certificates.crt
    '' + nixInit;
  };
}