Abstracting with nix-shell seems very difficult. Here’s an example of what I mean.
In ~/.config/nixpkgs/overlays/env.nix I have:
self: super:
let
candelaPkgs = import (fetchTarball {
url = https://github.com/NixOS/nixpkgs-channels/archive/14a9ca27e69e33ac8ffb708de08883f8079f954a.tar.gz;
sha256 = "1grsq8mcpl88v6kz8dp0vsybr0wzfg4pvhamj42dpd3vgr93l2ib";
}) {};
in {
env = {
candela = super.mkShell {
name = "candela";
buildInputs = with candelaPkgs; [
cairo
nodejs-9_x
nodePackages_8_x.node-gyp
nodePackages.lerna
pkgconfig
];
};
};
}
nix-shell -p env.candela gives me this error:
these derivations will be built:
/nix/store/jnd4q1camnxqyf2gh05igqh4z3wk5kmn-candela.drv
building '/nix/store/jnd4q1camnxqyf2gh05igqh4z3wk5kmn-candela.drv'...
nobuildPhase
This derivation is not meant to be built, aborting
builder for '/nix/store/jnd4q1camnxqyf2gh05igqh4z3wk5kmn-candela.drv' failed with exit code 1
error: build of '/nix/store/jnd4q1camnxqyf2gh05igqh4z3wk5kmn-candela.drv' failed
But if I now create a file dummy.nix:
{ pkgs ? import <nixpkgs> {} }:
pkgs.env.candela
and I do nix-shell dummy.nix then I get a shell environment for Candela.
So when I say “abstracting seems difficult” what I mean is, creating the overlay is almost enough to get this effect of a “library” of shell environments, but I still have to do this artificial-seeming step of creating a barebones nix file with which to invoke nix-shell.
I could write a shell utility that creates that nix file in /tmp then runs nix-shell but it feels like I’m missing a native way to do it.
And I’ll just add: I realize my example here would be better off in a shell.nix file in a GitHub repo, but I’m just using it as an example of the pattern; there may be other shell environments I want to compose that are not project-specific, and I’m trying to learn the mechanics of how to make this work in a reusable or persistent way using the Nix tools.
Thanks!
roni
