Hello everyone,
I was trying to understand how to use `define-configuration` with some
practice and couldn't understand what goes wrong.
It took for example to write a `luanti-game-configuration` that could,
when serialized, generate a configuration file for the Luanti server. I
only started with 1 parameter.
When I try to serialize a configuration instance to a file, the content
of this file is empty.
Here is the code defining my `luanti-game-configuration`:
;; -*- mode: scheme; -*-
;; Luanti game configuration
(use-modules (gnu services configuration)
(guix gexp))
;; Define the maybe string
(define-maybe string)
;; Define serializer functions
(define (serialize-luanti-admin-name field-name value)
"Serialize the Luanti admin name field for the config file."
(let ((field-real-name "name"))
#~(string-append #$field-real-name " = " #$value)))
;; Define the Luanti Game configuration
(define-configuration luanti-game-configuration
(admin-name
maybe-string
"Username of the administrator."
(serializer serialize-luanti-admin-name)))
;; Define Luanti game configuration file generator
(define (minetest.conf config)
"Return the Luanti config file."
(plain-file "minetest.conf"
(with-output-to-string
(lambda ()
(serialize-configuration
config
luanti-game-configuration-fields)))))
After I evaluate this on the `guix repl`, I create an instance of my new config
and serialize it to a file object doing like this:
(define test
(luanti-game-configuration
(admin-name "mememe")))
(minetest.conf test)
The REPL return me this:
$7 = #<<plain-file> name: "minetest.conf" content: "" references: ()>
As reference, I based my practical test code on what I could read on
some system services code and on the actual devel manual:
https://guix.gnu.org/manual/devel/en/html_node/Complex-Configurations.html
What did I miss ?
Best regards
-------
Gendre Sébastien
