attempt metasploit default nix

default.nix

args : with args; 
rec {
  src = fetchurl {
    url = http://downloads.metasploit.com/data/releases/framework-latest.tar.bz2;
    sha256 = "1irw71r9rymn826s7rwmk0rmjsk0gdfy75c1wwalln81r25x9n8x";
  };

  buildInputs = [makeWrapper];
  configureFlags = [];

  doInstall = fullDepEntry(''
    mkdir -p $out/share/msf
    mkdir -p $out/bin

    cp -r * $out/share/msf

    for i in $out/share/msf/msf*; do
        makeWrapper $i $out/bin/$(basename $i) --prefix RUBYLIB : $out/share/msf/lib
    done
  '') ["minInit" "defEnsureDir" "doUnpack" "addInputs"];

  /* doConfigure should be specified separately */
  phaseNames = ["doInstall" (doPatchShebangs "$out/share/msf")];
      
  name = "metasploit-framework-4.11.3";
  meta = {
    description = "Metasploit Framework - a collection of exploits";
    homepage = "https://www.metasploit.com/";
    license = stdenv.lib.licenses.bsd3;
    maintainers = with stdenv.lib.maintainers; [ rdesfo ];
    platforms = stdenv.lib.platforms.all;
  };
}

both

nix-build -A msf

and

nix-env -f . -iA msf

complete without returning an error, but when I run msfconsole

$ msfconsole 
[*] Metasploit requires the Bundler gem to be installed
    $ gem install bundler

so I tried running msfconsole in nix-shell

$ nix-shell -p bundler
$ msfconsole 
fatal: Not a git repository (or any of the parent directories): .git
Bundler could not find compatible versions for gem "bcrypt":
  In Gemfile:
    metasploit-framework (>= 0) ruby depends on
      bcrypt (>= 0) ruby
Could not find gem 'bcrypt (>= 0) ruby', which is required by gem 'metasploit-framework (>= 0) ruby', in any of the sources.

I also tried using the bundix tool which can be found here, but I couldn't get this to build.