[Nix-dev] How to package Heroku Toolbelt?

[Alex Berg]

Excellent! I've got it working now. For the curious ones, I pasted my
successful package below.

Now, another question. After I install the Heroku Toolbelt, the `heroku`
command is available on the command-line. But, I can't run it because I
haven't installed Ruby.

Question 4: Is there some way to tell Nix that Ruby is a run-time
dependency of this package, and it should install the `ruby` package?

If that's the wrong idea, I want to know why. Is it that, each `nix-env
--install` command should expose only one application? I agree that Ruby is
an app, but is Heroku Toolbelt an app? The Toolbelt is just a Ruby script,
which is useless without Ruby. So...installing the Toolbelt should also
install Ruby, right? Help me understand the logic here.

Question 5: Why must I specify the "patchShebangs" function? The NixPkgs
manual says the "fixupPhase" does this automatically. "It rewrites the
interpreter paths of shell scripts to paths found in PATH".
See NixPkgs Manual: 3.4.8. The Fixup Phase:
http://nixos.org/nixpkgs/manual/#idp638240




stdenv.mkDerivation rec {
  name = "heroku-toolbelt";

  src = fetchurl {
    url = "
https://s3.amazonaws.com/assets.heroku.com/heroku-client/heroku-client.tgz";
    sha256 = "00zqj9jwcklfyq5k3v81dwlzrrjm8axkgx7mixcb1kghjjlsdzv2";
  };

  # The "heroku" command is a Ruby script, so do we need to include `ruby`
here?
  # Ruby isn't necessary to build it, so why include it in the
"BuildInputs"?
  #nativeBuildInputs = [ ruby ];

  installPhase = " mkdir -p $out; mv ./* $out; ";
  # The docs say the "fixupPhase" does this. Can I just use that?
  #postInstall = "patchShebangs $out;";

  phases = [ "unpackPhase" "installPhase" "fixupPhase" ];

  meta = { <snip> };
}



On Thu, Nov 14, 2013 at 5:57 PM, Vladimír Čunát <vcunat at gmail.com> wrote:

> On 11/14/2013 10:44 AM, Alex Berg wrote:
>
>> [chexxor at nixos:~]$ nix-build /my-sources/pkgs/top-level/all-packages.nix
>> -A heroku-toolbelt
>> these derivations will be built:
>>    /nix/store/226khb1zh9kb94wwc27as2kxiyrqmqkj-heroku-toolbelt.drv
>> building path(s)
>> `/nix/store/ibh9r574dd14wd01xpmldy90c69z8lfh-heroku-toolbelt'
>> building /nix/store/ibh9r574dd14wd01xpmldy90c69z8lfh-heroku-toolbelt
>> unpacking sources
>> punpacking source archive
>> /nix/store/dfryky194z2bv179pd4jf3ny2gn9di02-heroku-client.tgz
>> source root is heroku-client
>> builder for
>> `/nix/store/226khb1zh9kb94wwc27as2kxiyrqmqkj-heroku-toolbelt.drv' failed
>> to produce output path
>> `/nix/store/ibh9r574dd14wd01xpmldy90c69z8lfh-heroku-toolbelt'
>> error: build of
>> `/nix/store/226khb1zh9kb94wwc27as2kxiyrqmqkj-heroku-toolbelt.drv' failed
>>
>
> The error just means that the builder didn't create anything in the output
> path (passed in $out variable). But it doesn't seem you even wanted to do
> that yet ;-)
>
> Q1: the script can't be used as it is, because it installs into wrong
> paths (/usr/local/...).
>
> Q2: the source of the tarball doesn't really matter. It needs to always
> have the same hash. (You can even specify multiple sources, for the case
> that some are unavailable.)
>
>
> If the program is a ruby script, then you need to patch its shebang to use
> ruby from nix store and not #!/usr/bin/ruby. For that it should be enough
> to have postInstall = "patchShebangs $out"; with ruby in buildInputs and
> assuming you get the scripts into $out in installPhase.
>
>
> Vlada
>
>
>
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>
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