[bug#60521] [PATCH] home: Add home-stow-migration-service.

[Bruno Victal]

On 2023-01-03 16:55, Giacomo Leidi via Guix-patches via wrote:
> * gnu/home/services.scm (dotfiles-for-app): New variable;
> (home-stow-migration-configuration): new variable;
> (home-stow-migration-service): new variable.
> * doc/guix.texi: Document it.
> ---
>  doc/guix.texi         | 50 +++++++++++++++++++++++++++++++++++++++++++
>  gnu/home/services.scm | 49 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 99 insertions(+)
> 
> diff --git a/doc/guix.texi b/doc/guix.texi
> index 5c85680831..40c36f65c4 100644
> --- a/doc/guix.texi
> +++ b/doc/guix.texi
> @@ -109,6 +109,7 @@ Copyright @copyright{} 2022 Reily Siegel@*
>  Copyright @copyright{} 2022 Simon Streit@*
>  Copyright @copyright{} 2022 (@*
>  Copyright @copyright{} 2022 John Kehayias@*
> +Copyright @copyright{} 2023 Giacomo Leidi@*
>  
>  Permission is granted to copy, distribute and/or modify this document
>  under the terms of the GNU Free Documentation License, Version 1.3 or
> @@ -41119,6 +41120,55 @@ to use alternative services to implement more 
> advanced use cases like
>  read-only home.  Feel free to experiment and share your results.
>  @end defvr
>  
> +@deffn {Scheme Procedure} home-stow-migration-service
> +Return a service which is very similiar to @code{home-files-service-type}
> +(and actually extends it), but designed to ease the way into using Guix

Procedures in Guix are almost always Scheme functions, perhaps you could write 
this as:
    @defun home-stow-migration-service

> +Home for GNU Stow users.  This service allows users to point Guix Home to
> +their Stow directory and have their file automatically deployed to their home
> +directory just like Stow would, without migrating all of their dotfiles to 
> Guix
> +native configurations.
> +
> +A typical Stow setup consists of a source directory and a target directory.
> +The source directory must be structured as follows:
> +
> +@example
> +~$ tree -a .dotfiles/
> +.dotfiles/
> +├── git
> +│   └── .gitconfig
> +├── gpg
> +│   └── .gnupg
> +│       ├── gpg-agent.conf
> +│       └── gpg.conf
> +├── guile
> +│   └── .guile
> +├── guix
> +│   └── .config
> +│       └── guix
> +│           ├── channels.scm
> +│           └── .gitignore
> +├── nix
> +│   ├── .config
> +│   │   └── nixpkgs
> +│   │       └── config.nix
> +│   └── .nix-channels
> +├── tmux
> +│   └── .tmux.conf
> +└── vim
> +    └── .vimrc
> +
> +13 directories, 10 files
> +@end example
> +
> +A suitable configuration would then be:
> +
> +@lisp
> +  (home-stow-migration-service
> +   (string-append (getenv "HOME")
> +                  "/.dotfiles"))
> +@end lisp
> +@end deffn
> +
>  @defvr {Scheme Variable} home-xdg-configuration-files-service-type
>  The service is very similiar to @code{home-files-service-type} (and
>  actually extends it), but used for defining files, which will go to

In a similar vein, this could be written as:
    @defvar home-xdg-configuration-files-service-type

> diff --git a/gnu/home/services.scm b/gnu/home/services.scm
> index 99035686f1..996647c592 100644
> --- a/gnu/home/services.scm
> +++ b/gnu/home/services.scm
> @@ -1,6 +1,7 @@
>  ;;; GNU Guix --- Functional package management for GNU
>  ;;; Copyright © 2021 Andrew Tropin <andrew@trop.in>
>  ;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
> +;;; Copyright © 2023 Giacomo Leidi <goodoldpaul@autistici.org>
>  ;;;
>  ;;; This file is part of GNU Guix.
>  ;;;
> @@ -21,6 +22,7 @@ (define-module (gnu home services)
>    #:use-module (gnu services)
>    #:use-module ((gnu packages package-management) #:select (guix))
>    #:use-module ((gnu packages base) #:select (coreutils))
> +  #:use-module (guix build utils)
>    #:use-module (guix channels)
>    #:use-module (guix monads)
>    #:use-module (guix store)
> @@ -33,13 +35,16 @@ (define-module (gnu home services)
>    #:use-module (guix i18n)
>    #:use-module (guix modules)
>    #:use-module (srfi srfi-1)
> +  #:use-module (ice-9 ftw)
>    #:use-module (ice-9 match)
> +  #:use-module (ice-9 string-fun)
>    #:use-module (ice-9 vlist)
>  
>    #:export (home-service-type
>              home-profile-service-type
>              home-environment-variables-service-type
>              home-files-service-type
> +            home-stow-migration-service
>              home-xdg-configuration-files-service-type
>              home-xdg-data-files-service-type
>              home-run-on-first-login-service-type
> @@ -49,6 +54,7 @@ (define-module (gnu home services)
>  
>              environment-variable-shell-definitions
>              home-files-directory
> +            home-stow-migration-configuration
>              xdg-configuration-files-directory
>              xdg-data-files-directory
>  
> @@ -315,6 +321,49 @@ (define home-files-service-type
>                  (description "Files that will be put in
>  @file{~~/.guix-home/files}, and further processed during activation.")))
>  
> +(define (dotfiles-for-app app-dir)
> +  "Return a list of objects compatible with @{home-files-service-type}'s
> +value.  Each object is a pair where the first element is the relative path
> +of a file and the second is a gexp representing the file content.  Objects 
> are
> +generated by recursively visiting APP-DIR and mapping its contents to the

Instead of `APP-DIR', you can use the @var command:
    @var{app-dir}

> +user's home directory."
> +  (let ((app-absolute-path (canonicalize-path app-dir)))
> +    (map (lambda (path)
> +           (let ((app-file-relative-path
> +                  (string-replace-substring path
> +                                           (string-append app-absolute-path 
> "/")
> +                                           "")))
> +             (list app-file-relative-path
> +                   (local-file path
> +                               (string-append "home-stow-migration-"
> +                                              (string-replace-substring
> +                                               app-file-relative-path
> +                                               "/" "-"))))))
> +         (find-files app-absolute-path))))
> +
> +(define (home-stow-migration-configuration stow-dir)
> +  "Return a list of objects compatible with @{home-files-service-type}'s
> +value, generated following GNU Stow's algorithm using STOW-DIR as input
> +directory."

Same as above.

> +  (define (dir-contents dir)
> +    (scandir dir
> +             (lambda (name)
> +               (not (member name '("." ".."))))))
> +  (fold append
> +        '()
> +        (map (lambda (app-dir)
> +               (dotfiles-for-app
> +                (string-append stow-dir "/" app-dir)))
> +             (dir-contents stow-dir))))
> +
> +(define-public (home-stow-migration-service stow-dir)
> +  "Return a service extending @{home-files-service-type} with files from
> +STOW-DIR.  Files will be put in the user's home directory following GNU

Same as above.

> +Stow's algorithm, and further processed during activation."
> +  (simple-service 'home-stow-migration-service
> +                  home-files-service-type
> +                  (home-stow-migration-configuration stow-dir)))
> +
>  (define xdg-configuration-files-directory ".config")
>  
>  (define (xdg-configuration-files files)
> 
> base-commit: 473692b812b4ab4267d9bddad0fb27787d2112ff


Cheers,
Bruno