Systems

To create a new system, add a new directory to your systems directory.

Note

Remember to run git add when creating new files!

# Create a directory in the `systems` directory for a new system. This should follow
# Snowfall Lib's required system target format to ensure that the correct architecture
# and output are used.
mkdir -p ./systems/x86_64-linux/my-system

Now create the Nix file for the system at systems/x86_64-linux/my-system/default.nix.

{
    # Snowfall Lib provides a customized `lib` instance with access to your flake's library
    # as well as the libraries available from your flake's inputs.
    lib,
    # An instance of `pkgs` with your overlays and packages applied is also available.
    pkgs,
    # You also have access to your flake's inputs.
    inputs,

    # Additional metadata is provided by Snowfall Lib.
    system, # The system architecture for this host (eg. `x86_64-linux`).
    target, # The Snowfall Lib target for this system (eg. `x86_64-iso`).
    format, # A normalized name for the system target (eg. `iso`).
    virtual, # A boolean to determine whether this system is a virtual target using nixos-generators.
    systems, # An attribute map of your defined hosts.

    # All other arguments come from the system system.
    config,
    ...
}:
{
    # Your configuration.
}

This system will be made available on your flake’s nixosConfigurations, darwinConfigurations, or one of Snowfall Lib’s virtual *Configurations outputs with the same name as the directory that you created.

Systems can have additional specialArgs and modules configured within your call to mkFlake. See the following for an example which adds a NixOS module to a specific host and sets a custom value in specialArgs.

{
  description = "My Flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.05";

    snowfall-lib = {
      url = "github:snowfallorg/lib";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = inputs:
        inputs.snowfall-lib.mkFlake {
            inherit inputs;
            src = ./.;

            # Add modules to all NixOS systems.
            systems.modules.nixos = with inputs; [
                # my-input.nixosModules.my-module
            ];

            # If you wanted to configure a Darwin (macOS) system.
            # systems.modules.darwin = with inputs; [
            #   my-input.darwinModules.my-module
            # ];

            # Add a module to a specific host.
            systems.hosts.my-host.modules = with inputs; [
                # my-input.nixosModules.my-module
            ];

            # Add a custom value to `specialArgs`.
            systems.hosts.my-host.specialArgs = {
                my-custom-value = "my-value";
            };
        };
}