Problem on LXQt service definition

Problem on LXQt service definition

[Reza Alizadeh Majd]

Hi, 

I'll try to create a service for `lxqt-desktop` based on same definition on [nixos](https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/x11/desktop-managers/lxqt.nix). 
but my service definition won't start and  here is my proposed definition for this service:


;;;
;;; LXQt desktop service.
;;;

(define-record-type* <lxqt-desktop-configuration> lxqt-desktop-configuration
  make-lxqt-desktop-configuration
  lxqt-desktop-configuration
  (lxqt-package lxqt-package (default lxqt)))

(define (lxqt-shepherd-service config)
  "Return a shepherd service for @command{lxqt-session}"
  (let ((lxqt-session ((package-direct-input-selector "lxqt-session") 
                       (lxqt-package config))))
    (list (shepherd-service
            (provision '(lxqt))
            ; (requirement '())
            (documentation "Run the lxqt session")
            (start #~(make-forkexec-constructor
                      (list(string-append #$lxqt-session "/bin/startlxqt"))
                      #:environment-variables
                      (list (string-append "XDG_CONFIG_DIRS=" 
                                           "$XDG_CONFIG_DIRS;/run/current-system/profile/etc/xdg")
                            (string-append "XDG_DATA_DIRS="
                                           "$XDG_DATA_DIRS;/run/current-system/profile/share"))
            (stop #~(make-kill-destructor))))))

(define lxqt-desktop-service-type
  (service-type
    (name 'lxqt-desktop)
    (extensions
      (list
            (service-extension shepherd-root-service-type
                               lxqt-shepherd-service)
            (service-extension profile-service-type
                               (compose list 
                                        lxqt-package))))
    (default-value (lxqt-desktop-configuration))
    (description "Run the LXQt desktop environment.")))

(define-deprecated (lxqt-desktop-service #:key 
                                         (config 
                                          (lxqt-desktop-configuration)))
  lxqt-desktop-service-type
  "Return a service that adds the @code{lxqt} package to the system profile, and 
extends polkit with the actions from @code{lxqt-policykit}."
  (service lxqt-desktop-service-type config))


could anyone help on this matter ? 

Re: Problem on LXQt service definition

[Meiyo Peng]

Hi,

Reza Alizadeh Majd writes:

> I'll try to create a service for `lxqt-desktop` based on same definition on [nixos](https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/x11/desktop-managers/lxqt.nix).
> but my service definition won't start and  here is my proposed definition for this service:

Thank you for your work on LXQt.

> ;;;
> ;;; LXQt desktop service.
> ;;;
>
> (define-record-type* <lxqt-desktop-configuration> lxqt-desktop-configuration
>   make-lxqt-desktop-configuration
>   lxqt-desktop-configuration
>   (lxqt-package lxqt-package (default lxqt)))
>
> (define (lxqt-shepherd-service config)
>   "Return a shepherd service for @command{lxqt-session}"
>   (let ((lxqt-session ((package-direct-input-selector "lxqt-session")
>                        (lxqt-package config))))
>     (list (shepherd-service
>             (provision '(lxqt))
>             ; (requirement '())
>             (documentation "Run the lxqt session")
>             (start #~(make-forkexec-constructor
>                       (list(string-append #$lxqt-session "/bin/startlxqt"))
>                       #:environment-variables
>                       (list (string-append "XDG_CONFIG_DIRS="
>                                            "$XDG_CONFIG_DIRS;/run/current-system/profile/etc/xdg")
>                             (string-append "XDG_DATA_DIRS="
>                                            "$XDG_DATA_DIRS;/run/current-system/profile/share"))
>             (stop #~(make-kill-destructor))))))

I don't think we should start the LXQt session from a shepherd service.
A desktop session should be started by a display manager like GDM or
SDDM.  A display manager can find these desktop sessions and provides
choices on login screen if a desktop package provides correct session
files in prefix/share/xsessions (or prefix/share/wayland-sessions for
wayland sessions).  I am not a nix expert but I think the nix file you
referred to tries to define a desktop session file for LXQt rather than
automatically start it upon system startup.

> (define lxqt-desktop-service-type
>   (service-type
>     (name 'lxqt-desktop)
>     (extensions
>       (list
>             (service-extension shepherd-root-service-type
>                                lxqt-shepherd-service)
>             (service-extension profile-service-type
>                                (compose list
>                                         lxqt-package))))
>     (default-value (lxqt-desktop-configuration))
>     (description "Run the LXQt desktop environment.")))
>
> (define-deprecated (lxqt-desktop-service #:key
>                                          (config
>                                           (lxqt-desktop-configuration)))
>   lxqt-desktop-service-type
>   "Return a service that adds the @code{lxqt} package to the system profile, and
> extends polkit with the actions from @code{lxqt-policykit}."
>   (service lxqt-desktop-service-type config))

Apparently we should not use (define-deprecated ...) to define new variables.

> could anyone help on this matter ?

What are you trying to achieve by adding the lxqt-desktop-service-type?


--
Meiyo Peng
https://www.pengmeiyu.com/

Re: Problem on LXQt service definition

[Reza Alizadeh Majd]

Hi, 

Thanks for your response. 

based on my researches about using LXQt as a service on guix (like other desktop services previously defined), I found following comment on LXQt's Github: https://github.com/lxqt/lxqt/issues/1521#issuecomment-405097453

It seems that I need to customize `$XDG_CONFIG_DIRS` in order to be able to load  session files from `prefix/etc/share` instead of `prefix/etc/xdg` but I couldn't find a proper way to do this, and  hoped that defining a shepherd service with modified environment variables in it's start script could help. 

do we have any reference about modification of environment variables during service start? 

Thanks,
Reza



On Wed, May 15, 2019, at 7:58 AM, Meiyo Peng wrote:
> Hi,
> 
> Reza Alizadeh Majd writes:
> 
> > I'll try to create a service for `lxqt-desktop` based on same definition on [nixos](https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/x11/desktop-managers/lxqt.nix).
> > but my service definition won't start and  here is my proposed definition for this service:
> 
> Thank you for your work on LXQt.
> 
> > ;;;
> > ;;; LXQt desktop service.
> > ;;;
> >
> > (define-record-type* <lxqt-desktop-configuration> lxqt-desktop-configuration
> >   make-lxqt-desktop-configuration
> >   lxqt-desktop-configuration
> >   (lxqt-package lxqt-package (default lxqt)))
> >
> > (define (lxqt-shepherd-service config)
> >   "Return a shepherd service for @command{lxqt-session}"
> >   (let ((lxqt-session ((package-direct-input-selector "lxqt-session")
> >                        (lxqt-package config))))
> >     (list (shepherd-service
> >             (provision '(lxqt))
> >             ; (requirement '())
> >             (documentation "Run the lxqt session")
> >             (start #~(make-forkexec-constructor
> >                       (list(string-append #$lxqt-session "/bin/startlxqt"))
> >                       #:environment-variables
> >                       (list (string-append "XDG_CONFIG_DIRS="
> >                                            "$XDG_CONFIG_DIRS;/run/current-system/profile/etc/xdg")
> >                             (string-append "XDG_DATA_DIRS="
> >                                            "$XDG_DATA_DIRS;/run/current-system/profile/share"))
> >             (stop #~(make-kill-destructor))))))
> 
> I don't think we should start the LXQt session from a shepherd service.
> A desktop session should be started by a display manager like GDM or
> SDDM.  A display manager can find these desktop sessions and provides
> choices on login screen if a desktop package provides correct session
> files in prefix/share/xsessions (or prefix/share/wayland-sessions for
> wayland sessions).  I am not a nix expert but I think the nix file you
> referred to tries to define a desktop session file for LXQt rather than
> automatically start it upon system startup.
> 
> > (define lxqt-desktop-service-type
> >   (service-type
> >     (name 'lxqt-desktop)
> >     (extensions
> >       (list
> >             (service-extension shepherd-root-service-type
> >                                lxqt-shepherd-service)
> >             (service-extension profile-service-type
> >                                (compose list
> >                                         lxqt-package))))
> >     (default-value (lxqt-desktop-configuration))
> >     (description "Run the LXQt desktop environment.")))
> >
> > (define-deprecated (lxqt-desktop-service #:key
> >                                          (config
> >                                           (lxqt-desktop-configuration)))
> >   lxqt-desktop-service-type
> >   "Return a service that adds the @code{lxqt} package to the system profile, and
> > extends polkit with the actions from @code{lxqt-policykit}."
> >   (service lxqt-desktop-service-type config))
> 
> Apparently we should not use (define-deprecated ...) to define new variables.
> 
> > could anyone help on this matter ?
> 
> What are you trying to achieve by adding the lxqt-desktop-service-type?
> 
> 
> --
> Meiyo Peng
> https://www.pengmeiyu.com/
>

Re: Problem on LXQt service definition

[L p R n d n]

Hello

"Reza Alizadeh Majd" <r.majd@pantherx.org> writes:

> Hi, 
>
> Thanks for your response. 
>
> based on my researches about using LXQt as a service on guix (like other desktop
> services previously defined), I found following comment on LXQt's Github:
> https://github.com/lxqt/lxqt/issues/1521#issuecomment-405097453
>
> It seems that I need to customize `$XDG_CONFIG_DIRS` in order to be able to load
> session files from `prefix/etc/share` instead of `prefix/etc/xdg` but I couldn't
> find a proper way to do this, and hoped that defining a shepherd service with
> modified environment variables in it's start script could help.
>
> do we have any reference about modification of environment variables during service start? 
>
> Thanks,
> Reza
>

Sorry if I'm beside the point, just want to be sure, did you try to
get lxqt by just adding it to your system profile?
I tried lxqt once and I don't remember experiencing the problems
described in your link.

Also, from what I've seen in gnu/services/desktop.scm, desktop services are
often just polkit or dbus extensions, if some lxqt packages need a
special environment variable, another solution is to modify the package
definition with a `wrap-program` phase or something. This way, the
problem should be solved even if the user doesn't use the service.



Thanks,

L  p R n  d n