gistfile1.txt

{ dockerTools }:
let
  inherit (dockerTools) buildImage pullImage;
in
buildImage {
  name = "ha-nest-climate-fix";
  tag = "latest";
  fromImage = pullImage {
    imageName = "homeassistant/home-assistant";
    imageDigest = "sha256:d50285bfb61769507e8fd6dc5867512ee752b27c37f47e5308ba908b264ae5f9";
    sha256 = "008aadfmb49z7ss4952xdfnaz9ardfbd8ssd5xifqsklyq9ll24s";
    finalImageName = "homeassistant/home-assistant";
    finalImageTag = "latest";
  };
  diskSize = 4096;
  runAsRoot = ''
    sed -i 's/MAX_FAN_DURATION = 43200.*/MAX_FAN_DURATION = 900/' $out/usr/src/homeassistant/homeassistant/components/nest/climate.py
  '';
}

output.txt

$ nix-build -E "with import <nixpkgs> { }; callPackage ./ha.nix {} "
these 3 derivations will be built:
  /nix/store/i9rkdp5qam5b7pl4bs04wh5f5p5b755g-docker-layer-ha-nest-climate-fix.drv
  /nix/store/n34cim426lbwh6cm9lcmssbxy160z9xy-runtime-deps.drv
<snip>
Unpacking layer c6791f2632cee7c7bf46d546d7e383e35382dc217d377a0c86a801c291c56d56.tar
Unpacking layer b746e8a4e75e1f3358c2091d829c5cad7b357e86bb9702eabd07931ca0a708d1.tar
Unpacking layer 05c3095b86a564cd6f16cd6c927d8ac291777ba65a2d929a198ccf961a0702d6.tar
mount: /tmp/disk/mnt: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error.
       dmesg(1) may have more information after failed mount system call.
[   22.379487] reboot: Power down