Nix

[benclmnt]

Background: use Nix on MacOS

Where to start with Nix

Glossary

• derivation: package build task / recipe for a build action. The result is a store object
• store: /nix/store (by default)
• store path: path of store object inside /nix/store
• store object: sources (copied from outside of store), derivation output (result of build action), derivations (files describing build actions)
• ~/.nix-defexpr is where nixpkgs is stored.
• nixpkgs just refer to https://github.com/nixos/nixpkgs/. import <nixpkgs> {} is kinda similar to import (fetchGithub https://github.com/nixos/nixpkgs/)

Nix, the language

• https://nix.dev/tutorials/nix-language
• https://github.com/tazjin/nix-1p
• Official Manual: for reference only
• Best Practices

Nix Flakes

tldr: a standardized way to package a software in a hermetic way. like package.json. There is flake.lock that works similar to package.lock

• https://www.tweag.io/blog/2020-05-25-flakes/
• https://www.tweag.io/blog/2020-06-25-eval-cache/

useful commands

• nix shell [flakes] --command [binary name] [args]

[benclmnt]

Related issues:

• https://github.com/benclmnt/til/issues/4

[benclmnt]

An example of a flake.nix for a golang monorepo that requires go1.17

{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-22.05-darwin";
  };

  outputs = { self, nixpkgs }:
    let
      # Systems supported
      allSystems = [
        "x86_64-darwin" # 64-bit Intel macOS
        "aarch64-darwin" # 64-bit ARM macOS
      ];

      # Helper to provide system-specific attributes
      forAllSystems = f: nixpkgs.lib.genAttrs allSystems (system: f {
        pkgs = import nixpkgs { inherit system; };
      });
    in
    {
      devShells = forAllSystems ({ pkgs }: {
        default = pkgs.mkShell {
          packages = with pkgs; [
            go_1_17
            gotools
            buf
          ];

          shellHook = ''
          go env -w GONOPROXY="golang.org,github.com,go.uber.org"
          '';
        };
      });
    };
}