Instalar Emacs como servicio

1. Servicio
2. Cliente
- 2.1. fichero .desktop
- 2.2. Icono
3. Problemas

Los usarios de emacs tenemos un complejo de inferioridad respecto del tiempo de arranque de la aplicación. Se han hecho muchos intentos para mejorarlo, como el portable dumper o profile-dot-emacs, pero es innegable que vi y vscode arrancan más rápido.

Al final, la mejor solución no es reducir el tiempo de arranque, sino camuflarlo. La mayoría de usuarios de emacs no abren una instancia cada vez que lo necesitan, sino que emacs está corriendo permanentemente y se abren nuevas frames o windows. La forma de trabajo sería la siguiente

Abrir una instancia de emacs y arrancar el servidor.
Cuando se necesite abrir un fichero, no se ejecuta una nueva instancia de emacs, sino que se utiliza emacsclient. Este se conecta a la instancia inicial.

El hack final es hacer que la instancia de emacs se arranque automáticamente al iniciar sesión, o mejor aún, cuando se inicia el sistema como un servicio.

Utilizo este mismo fichero org para publicar esta entrada y para configurar mis ordenadores GNU Linux, con literate programming. Para activar la ejecución de bloques shell necesito ejecutar el siguiente bloque elisp:

  (org-babel-do-load-languages
   'org-babel-load-languages
   '(
     (shell . t)))

1. Servicio

Basado en https://www.emacswiki.org/emacs/EmacsAsDaemon, utilizo la versión de centos, ya que funciona en centos y ubuntu. La diferencia está en el directorio que uso para dejar la unit:

En centos es /usr/lib/systemd/system/emacs@.service
Ubuntu es /lib/systemd/system/emacs@.service

Este bloque de código se ejecuta en el directorio /sudo::, lo que indica a emacs que debe ejecutarlo con sudo utilizando TRAMP.

SERVICEFILE=/lib/systemd/system/emacs@.service
EMACSDIR=/usr/local/bin

sudo tee > $SERVICEFILE <<EOF
[Unit]
Description=Emacs: the extensible, self-documenting text editor

[Service]
Type=forking
ExecStart=$EMACSDIR/emacs --daemon --user %i
ExecStop=$EMACSDIR/emacsclient --eval "(progn (setq kill-emacs-hook 'nil) (kill-emacs))"
Restart=always
User=%i
WorkingDirectory=/home/%i

[Install]
WantedBy=multi-user.target
EOF

chmod u+r,g+r,o+r $SERVICEFILE

sudo systemctl daemon-reload 
sudo systemctl enable emacs@alvaro

2. Cliente

2.1. fichero `.desktop`

Sistemas con Gnome o KDE utilizan ficheros .desktop para añadir aplicaciones a sus menús de inicio. Voy a añadir una nueva aplicación para emacsclient, basándome en el fichero .desktop que ya viene con emacs y la documentación en https://specifications.freedesktop.org/desktop-entry-spec/latest/index.html

EMACSDIR=/usr/local/bin

cat > ~/.local/share/applications/emacsclient.desktop <<EOF
#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Name=GNU Emacs Client
GenericName=Text Editor
Comment=View and edit files
MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;
Exec=$EMACSDIR/emacsclient --create-frame --alternate-editor "" %F
Type=Application
Icon=$HOME/.local/share/applications/emacsclient.svg
Terminal=false
Categories=Utility;Development;TextEditor;
StartupWMClass=Emacs
EOF

2.2. Icono

Para estar seguro de que el icono existe, copio el fichero svg que tengo para emacs26 al lado del fichero .desktop.

cat > ~/.local/share/applications/emacsclient.svg <<EOF
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:cc="http://creativecommons.org/ns#"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   xmlns:xlink="http://www.w3.org/1999/xlink"
   xml:space="preserve"
   id="svg4768"
   viewBox="0.171 0.201 512 512"
   height="48"
   width="48"
   version="1.0"><metadata
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           rdf:resource="http://purl.org/dc/dcmitype/StillImage" /><dc:title></dc:title></cc:Work></rdf:RDF></metadata><!-- Gnu Emacs Icon
   Copyright (C) 2008-2019 Free Software Foundation, Inc.

   Author: Nicolas Petton <nicolas@petton.fr>

   This file is part of GNU Emacs.

   GNU Emacs is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   GNU Emacs is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

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3. Problemas

emacsclient no encuentra el socket: añadir el parámetro -s con /tmp/emacs1000/server. El número 1000 indica el identificador del usuario. También puede especificarse la variable server-socket-dir al iniciar el servidor.

Álvaro González Sotillo

Instalar Emacs como servicio

Table of Contents

1. Servicio

2. Cliente

2.1. fichero `.desktop`

2.2. Icono

3. Problemas

Instalar Emacs como servicio

Table of Contents

1. Servicio

2. Cliente

2.1. fichero .desktop

2.2. Icono

3. Problemas

2.1. fichero `.desktop`