nixpkgs/pkgs/development/beam-modules/fetch-hex.nix

{ lib, stdenv, fetchurl }:

{ pkg
, version
, sha256
, meta ? { }
}:

with lib;

stdenv.mkDerivation ({
  pname = "hex-source-${pkg}";
  inherit version;
  dontBuild = true;
  dontConfigure = true;
  dontFixup = true;

  src = fetchurl {
    url = "https://repo.hex.pm/tarballs/${pkg}-${version}.tar";
    inherit sha256;
  };

  unpackCmd = ''
    tar -xf $curSrc contents.tar.gz
    mkdir contents
    tar -C contents -xzf contents.tar.gz
  '';

  installPhase = ''
    runHook preInstall
    mkdir "$out"
    cp -Hrt "$out" .
    success=1
    runHook postInstall
  '';

  inherit meta;
})