Introduction to Denix Extensions

Some features that contradict the philosophy of Denix or are purely optional can still be implemented as separate extensions. Also, if a configuration needs to provide a custom function or modify the behavior of an existing one - this can be done through a custom extension.

Currently, the extension API allows you to:

• Extend delib by adding new functions or overriding existing ones.
• Add modules that are automatically included in the configuration.

Usage

To add extensions, you need to pass the extensions argument to the delib.configurations function. This argument is a list of extensions.

Official extensions are located in delib.extensions (see All extensions). In addition to them, you can also add custom extensions in the following ways:

• If the extension is a single file:

delib.callExtension ./myExtension.nix

• If the extension consists of multiple files:

delib.mergeExtensions "myExtensionName" [
  (delib.callExtension ./myExtensionPart1.nix)
  (delib.callExtension ./myExtensionPart2.nix)
]

• If there are many extensions:

(delib.callExtensions { paths = [./myExtensions]; }).myExtension

Some extensions support their own configuration (not to be confused with module options). Configuration is done via withConfig:

delib.extensions.someExtension.withConfig {
  someOption = "value";
}

The parameter can be either an overlay or an attrset (it will automatically be converted to an overlay). For details, see NixOS Wiki - Overlays.

Example

delib.configurations {
  # ...
  extensions =
    with delib.extensions;
    with delib.callExtensions { paths = [./myExtensions]; };
    [
      args
      (base.withConfig (final: prev: {
        args.enable = true;
        hosts.type.types = prev.hosts.type.types ++ ["laptop"];
      }))
      (delib.callExtension ./myExtension.nix)
      extensionFromMyExtensions
      (anotherExtensionFromMyExtensions.withConfig { someConfig = "someValue"; })
    ];
}