Re: Re: org batch job using emacsclient?

[Sebastian Rose <sebastian_rose@gmx.de>]

Stefan Vollmar <vollmar@nf.mpg.de> writes:
> Gentlemen,
>
> thanks for the many helpful replies!
>
> To start with, it now works for me and I can measure a consistent speedup of 7x
> (!) for using emacsclient - in an interactive web service (conversion of
> org-files to HTML) the difference between 0.35 s and 2.40 s (average) is
> significant.

That was to be expected :)

> (1) Having started the emacs server with
>
> emacs --daemon=org
>
> this shell script works for me:
>
> #!/bin/sh
> emacsclient -s org
> --eval "(progn
> (add-to-list 'load-path \"/opt/org-6.33c/lisp/\")
> (require 'org)(require 'org-exp)
> (setq org-export-headline-levels 2)
> (find-file \"$1\")
> (org-export-as-html 2 nil nil nil nil \".\")
> (kill-buffer))"
>
> I have added a (kill-buffer) statement for cleaning up (I observed an increasing
> number of emacsclient processes before), is this a good solution?


  Does it help? Then I think it's ok.

  The `usual' way to close a server buffer is `C-x #' which is bound to
  the function `server-edit'.  That's what I use in org-protocol.el. The
  name is somewhat confusing, though.

  Another trick is, to simply not wait for a reply from the server at
  all:

     emacsclient --no-wait ...


> (2) A problem remains with (1): it seems that I need to "name" the daemon.
> Otherwise there could be a conflict with Emacs daemons started by other users.
> How can I make sure the daemon is running if the script requires it? I read
> about a "-a" option for emacsclient - how would this work in my case?

  I would start Emacs in rc.emacs-server like this (but maybe use no
  server at all, see below):

     /path/to/emacs -Q -l /etc/emacs-server/init.el --daemon=SERVER-NAME


     /path/to/emacsclient --no-wait --socket-name=SERVER-NAME xy.org

  You could also use an absolute path for the socket.

  and put all required setup into /etc/emacs-server/init.el. `-Q'
  ensures emacs will start correctly, even if a user without a
  home-directory (e.g. apache user) starts it and thus no ~/.emacs can
  be found (start-stop-daemon switches to the UID you tell it). Also, if
  started as root, emacs will _not_ load root's .emacs.


  Start Emacs in an /etc/init.d/rc.emacs-server script to make sure it
  starts when you restart the server. Use `start-stop-daemon' to do so
  [1] and provide the commands `start', `stop', `restart' and `status'
  maybe. A cron-job could check for a running emacs-server via

     /etc/init.d/rc.emacs-server status

  every 5 minutes or so. If that fails, re-start Emacs.

  Your script could check for the running Emacs, too, and restart it as
  necessary.

  Are you familiar with init.d stuff? There is an example file somewhere
  on Debian...
  http://github.com/SebastianRose/denycc/blob/master/scripts/rc.denycc
  is made from such an example file for Debian 4.0


  Access privileges might be important. Unfortunately I have no good
  concept at hand - I don't thing emacs-server offers one at all,
  actually. Something to read...

  At least I would add something like this to your emacsclient
  shell-script (insert you Apaches EUID for the 99):

  if [ 99 -ne $EUID ];then
      echo "Got to be a native American to execute this command!"
      exit 124
  fi





Best wishes

  Sebastian


== Footnotes: ====

[1] From `man start-stop-daemon' (German version - English version below):

    BESCHREIBUNG
       start-stop-daemon wird zur Steuerung der Erzeugung und Beendigung
       von Prozessen auf Syste‐ mebene verwendet. Durch die Verwendung
       einer der Abgleich-Optionen kann start-stop-daemon so
       konfiguriert werden, dass er existierende Instanzen von einem
       laufenden Prozess finden kann.

       Hinweis: Falls --pidfile nicht angegeben ist, verhält sich
       start-stop-daemon ähnlich zu killall(1).  start-stop-daemon wird
       die Prozesstabelle nach Prozessen durchsuchen, die auf den
       Prozessnamen, uid und/oder gid (falls angegeben) passen. Jeder
       passende Prozess wird --start daran hindern, den Daemon zu
       starten. Allen passenden Prozessen wird das KILL-Sig‐ nal
       geschickt, falls --stop angegeben ist. Für Daemons die langlebige
       Kinder haben, die ein --stop überleben sollen, müssen Sie eine
       PID-Datei angeben.

 * man -L en_US start-stop-daemon:

   DESCRIPTION
       start-stop-daemon is used to control the creation and termination
       of system-level pro‐ cesses.  Using one of the matching options,
       start-stop-daemon can be configured to find existing instances of
       a running process.

       Note: unless --pidfile is specified, start-stop-daemon behaves
       similar to killall(1).  start-stop-daemon will scan the process
       table looking for any processes which match the process name,
       uid, and/or gid (if specified). Any matching process will prevent
       --start from starting the daemon. All matching processes will be
       sent the KILL signal if --stop is specified. For daemons which
       have long-lived children which need to live through a --stop, you
       must specify a pidfile.