Finalize configuration format

[cilki]

The main bottleneck here is finishing the config format which is a critical component that everything else depends. It's user-facing, so it should be both intuitive and stable.

Some required features:

• Support multiboot images
• Flexible enough to conveniently support any kind of operating system
• Support custom provisioners for certain operating systems (MirrorlistProvisioner for certain Linux distributions, for example)
• JSON, YAML, and maybe even TOML
• Documentation can be generated from Rust structs

This format is what I was working towards previously, but I think there's still room for improvement:

{
  "name": "ArchLinux",
  "arch": "x86_64",
  "templates": [
    {
      "base": "ArchLinux",
      "iso_checksum": "sha1:3700a16d4fcabbd29e9a7fbc97da732c4577dc2a",
      "iso_url": "https://mirrors.edge.kernel.org/archlinux/iso/latest/archlinux-2022.05.01-x86_64.iso",
      "mirrorlist": [
        "https://mirrors.edge.kernel.org/archlinux/$repo/os/$arch"
      ],
      "root_password": "root",
      "storage_size": "4Gb",
      "provisioners": [
        {
          "type": "ansible",
          "playbook": "ansible.yml"
        }
      ]
    }
  ]
}

Since the above isn't fully implemented yet, there's still time to pivot onto a slightly better path if there is one.

[cilki]

TOML might actually be a reasonable format. Something like this is pretty easy to read:

name = "ArchLinux"
arch = "x86_64"
size = "128 Gb"

[[template]]
base = "ArchLinux"

[[template.source.iso]]
checksum = "sha1:3700a16d4fcabbd29e9a7fbc97da732c4577dc2a"
url = "https://mirrors.edge.kernel.org/archlinux/iso/latest/archlinux-2022.05.01-x86_64.iso"

[[template.provisioners.ansible]]
playbook = "ansible.yml"

[[template.provisioners.ansible]]
playbook = "ansible2.yml"

[template.provisioners.root_password]
plaintext = "root"

[template.provisioners.mirrorlist]
mirrors = [ "https://mirrors.edge.kernel.org/archlinux/$repo/os/$arch" ]

[cilki]

There's also RON:

(
  name: "Arch Linux example",
  description: "Example of how to build a simple Arch Linux image",
  arch: "x86_64",
  size: "16 Gb",
  source: Iso (
    checksum: "sha1:3700a16d4fcabbd29e9a7fbc97da732c4577dc2a",
    url: "https://mirrors.edge.kernel.org/archlinux/iso/latest/archlinux-2022.05.01-x86_64.iso",
  ),
  mold: ArchLinux (
    hostname: "ExampleArch",
    mirrorlist: [
      "https://mirrors.edge.kernel.org/archlinux/$repo/os/$arch"
    ],
    root_password: "root",
    packages: [
      "alacritty",
      "git",
      "neovim",
    ]
  ),
  fabricators: [
    Ansible (
      playbook: "ansible.yml"
    )
  ]
)

Although it would be easy to support multiple config formats technically, it's probably a good idea to choose one preferred format.