# Proposal to make guix system deployment more flexible

TLDR: Make `(operating-system)` into a "derivation capable of storing data" that can be triggered using a function `(guix-build-system)` to enable more flexible system management

### Context and end-goal
I am trying to port my NixOS managing system (https://git.dotya.ml/OpenVolt/nyxtumops) on guix to manage my systems where the expected goal is to be able to use public git repository to manage +200 systems at once through Continuous Integration and Delivery transparently to the user to provide https://snopyta.org -like libre service provider on a federated network to which new members can be added.

To do this i've defined a programming logic that separates the configuration per hostname and domain with file hierarchy applying configuration further by defining:
1. Global -- Configuration is applies to all systems using the solution

e.g. /users/kreyren.scm is expected to set user kreyren to all systems

2. Domain-wide -- Configuration applied only to the defined domain

e.g. /domains//default.scm is expected to define configuration for the defined domain

3. Specific to the system -- Applied only to specified system

e.g. domains//machines//default.scm is expected to define configuration only for the defined system

See the repository on https://git.dotya.ml/RiXotStudio/grilumops

### The issue

The currently used `(operating-system)` is basically a function with a lot of inputs with hard dependency on:
- bootloaders
- host-name
- file-systems
- timezone

Making it impossible to define a modular and expression independent solution through `(load)`-ing the files e.g.

Using command `guix system build src/default.scm` to execute following instructions:

```
────────────────────────────────────
       │ File: src/default.scm
────────────────────────────────────
...
   4   │ ;;; This file is the gateway in the system managing solution
,,,
  16   │ (load "users/kreyren.scm")
  17   │ (load "domains/rixotstudio.cz/default.scm")
  18   │ 
  19   │ (display "Finished")(newline)
```

Where the `(load "users/kreyren.scm") is important as the file is expected to define a `kreyren` user across all systems which is not possible on the current handling to do in modular and expression independent way as:

#### 1. Requires hard-written definition

```scm
;; First file
(define-public kreyren (name "kreyren")...)

;; Second file
(operating-system (users (user-account (source kreyren))))
```

Which breaks modularity as one file can't be used in different parts of the source code and is expression-dependent as it requires hard-written `(source kreyren)`

#### 2. Requires variable-driven layer

```scm
;; First file
(define-public my-username "kreyren")
...

;; Second file
(operating-system (users (user-account (name my-username)))))
```

which increases the complexity to the point where it significantly influences maintenance

#### 3. Defining a solution that constructs the (operating-system)

```scm

```

which increases the complexity to the point where the managing solution is unmaintainable and impossible to expand on in terms of features

### Proposed solution

Define `(operating-system)` into a "data-type capable of manipulating it's stored data" e.g. list, structure, etc.. and a function e.g. `(guix-build-system)` that reads the data from `(operating-system)` and applies it into a system build