Per host configuration

[aurora-xa]

Would you mind expanding on how to implement per host configurations?
I took a look at your personal config repo but I do not follow how you select which 'host' you are installing for.
Does it just 'work' i.e. hostname = which config it will pick ?
Many thanks

[dustinlyons]

Hi,

In designing this configuration, I made a tradeoff to not create per host configuration as I felt, at the time, reading other configurations was difficult as they were per host with many small module files.

So I wanted to make something more obvious, with Mac-specific and NixOS-specific code broken out into their own directories, filenames like packages, files, homebrew, etc, to denote clearly what's going on. Optimize for learnability over a more canonical configuration.

So it's currently limited to one machine of each platform type. I have a home lab server at home, but instead of adopting this configuration, I'll likely just maintain of fork of this repository for it.

Here's how the code works:

darwinConfigurations = nixpkgs.lib.genAttrs darwinSystems (system:
        darwin.lib.darwinSystem {
          inherit system;
          specialArgs = inputs;
          modules = [
            home-manager.darwinModules.home-manager
            nix-homebrew.darwinModules.nix-homebrew
            {
              nix-homebrew = {
                inherit user;
                enable = true;
                taps = {
                  "homebrew/homebrew-core" = homebrew-core;
                  "homebrew/homebrew-cask" = homebrew-cask;
                  "homebrew/homebrew-bundle" = homebrew-bundle;
                };
                mutableTaps = false;
                autoMigrate = true;
              };
            }
            ./hosts/darwin
          ];
        }
      );

This line:

darwinConfigurations = nixpkgs.lib.genAttrs darwinSystems (system:

says

Run the [genAttrs](https://noogle.dev/f/lib/genAttrs) function, with a list of strings and a function as arguments.

Here is our list of strings, darwinSystems:

darwinSystems = [ "aarch64-darwin" "x86_64-darwin" ];

So the genAttrs function maps over these two strings, and creates a key value pair where the key is the string and the value is the result of the function, which in our case is a darwin.lib.darwinSystem.

So darwinConfigurations ends up as:

darwinConfigurations = 
        "aarch64-darwin" = darwin.lib.darwinSystem {
          inherit system;
          specialArgs = inputs;
          modules = [
            home-manager.darwinModules.home-manager
            nix-homebrew.darwinModules.nix-homebrew
            {
              nix-homebrew = {
                inherit user;
                enable = true;
                taps = {
                  "homebrew/homebrew-core" = homebrew-core;
                  "homebrew/homebrew-cask" = homebrew-cask;
                  "homebrew/homebrew-bundle" = homebrew-bundle;
                };
                mutableTaps = false;
                autoMigrate = true;
              };
            }
            ./hosts/darwin
          ];
        }
      );

      "x86_64-darwin" = darwin.lib.darwinSystem {
        inherit system;
        specialArgs = inputs;
        modules = [
          home-manager.darwinModules.home-manager
          nix-homebrew.darwinModules.nix-homebrew
          {
            nix-homebrew = {
              inherit user;
              enable = true;
              taps = {
                "homebrew/homebrew-core" = homebrew-core;
                "homebrew/homebrew-cask" = homebrew-cask;
                "homebrew/homebrew-bundle" = homebrew-bundle;
              };
              mutableTaps = false;
              autoMigrate = true;
            };
          }
          ./hosts/darwin
        ];
      }
    );

This makes two hosts available by their platform name. When you run the build process, the scripts look for the platform by name.

Hope this helps!

[aurora-xa]

Thank you for the explanation - I will try and tweak!