Usage

The next few sections describe the different optnix concepts.

But first:

What's a module system, even?

A module system is a Nix library that allows you to configure a set of exposed options. All the systems mentioned above allow you to configure their respective options with your own values.

While this can be a powerful paradigm for modeling any configuration system, these options can be rather hard to discover. Some of these options are found through web interfaces (like https://search.nixos.org), but many options can remain out of sight without reading source code, such as external module options or external module systems.

More information on how module systems work can be found on nix.dev.

How optnix Works

optnix works by ingesting option lists that are generated from these module systems.

An option list is a list of JSON objects; each JSON object describes a single option, with the following values for an example option:

{
  "name": "services.nginx.enable",
  "description": "Whether to enable Nginx Web Server.",
  "type": "boolean",
  "default": {
    "_type": "literalExpression",
    "text": "false"
  },
  "example": {
    "_type": "literalExpression",
    "text": "true"
  },
  "loc": ["services", "nginx", "enable"],
  "readOnly": false,
  "declarations": [
    "/nix/store/path/nixos/modules/services/web-servers/nginx/default.nix"
  ]
}

Given an options attribute set, a list of these options can be generated using lib.optionAttrSetToDocList from nixpkgs, or by using wrapper functions provided with optnix as a Nix library. This will be seen in later examples.

Operation

There are two modes of operation: interactive (the default) and non-interactive.

Interactive mode will display a search UI that allows looking for options using fuzzy search keywords. Selected options in the list can also be evaluated in order to preview their values.

Non-interactive mode requires a valid option name as input, and will display the option and its values (if applicable) without any user interaction. This kind of output is useful when an option name is known, such as for scripting.

optnix is controlled through its configuration file (or files) that define "scopes". For more, look at the following pages:

• Scopes
• Configuration