nixmod2go

nix-mod-to-go

Tool to parse and generate Go struct definitions from Nix modules.

Usage

# Print help message
nixmod2go --help

# Generate Go code to stdout for module.nix
nixmod2go -f go module.nix

For more information, see the help message and the below example.

Example

Quick Start

Given a very simple Nix module module.nix:

{ lib, ... }: {
  options.services.xyz = {
    enable = lib.mkEnableOption "XYZ service";
    host = lib.mkOption {
      type = lib.types.str;
      default = "127.0.0.1";
      description = "Host to listen on.";
    };
    port = lib.mkOption {
      type = lib.types.int;
      default = 8080;
      description = "Port to listen on.";
    };
  };
}

Running nixmod2go -f go -O services.xyz module.nix will output the following Go code:

// Code generated by nixmod2go. DO NOT EDIT.
package main

// Config is the struct type for `config`.
type Config struct {
	// Enable: whether to enable XYZ service.
	Enable bool `json:"enable"`
	// Host: host to listen on.
	Host string `json:"host"`
	// Port: port to listen on.
	Port int `json:"port"`
}

Complete Example

example/module.nix contains an example Nix module that contains a lot of different option types. Using this file, 2 more files are generated:

• module.gen.json contains the generated JSON representation of the module.
• module.gen.go contains the generated Go structs code that the module config can be unmarshalled into.

module_test.go ensures that the generated Go types can be properly unmarshaled onto and marshaled from.

The command to generate these files is listed below in the update-example section.

Tasks

This README file can be executed using xc.

update-example

Update the generated example files.

go run . -f json ./example/module.nix ./example/module.gen.json
go run . -f go --go-package example ./example/module.nix ./example/module.gen.go
go test ./example