[X2go-Dev] Clean sessions

[Mike Gabriel]

Hi all,

On Mo 25 Jul 2011 15:12:32 CEST Moritz Struebe wrote:

>>> The first is probably better done as daemon/cron-job. The daemon needs
>>> extended rights, because it needs access to all sessions (this is
>>> relevant due to the postgres-implementation), and needs to run on every
>>> server. Running as x2gouser should do the trick, though.
>
>> Why can't this run in user context? I mean the user has priviledges to
>> create sessions, why can't he clean up after himself?
>
> He can, of course. But we also want to clean up sessions of people who
> only log in once in a while.

One reason for keeping a house keeper (someone who cleans up after  
you) is that you can fulfil your own tasks as quickly as possible.  
Most of the x2goserver scripts do not fork to background: the clients  
calls that script and waits for a return value. Each operation issued  
in that way should be really fast.

>>> The second is probably best placed in x2gocreatesession, as the user
>>> should have the rights to clean up it's old sessions (root normally may
>>> not access foreign homes via NFS).
>> Why is this cleanup better done at 'create session' time rather than at
>> 'listing sessions' time?
>
> List session should list sessions. You don't want it to have strange
> side-effects (IMO deleting files is such a strange side-effect).

I agree here fully. Esp. x2golistsessions has to come up with results  
quickly. One reason we use a database for querying session information  
opposed to collecting the details from the system state (ps aux etc.).

The problem that occurs, however, is that we indeed have home  
locations (NFS+Krb5, AFS, CIFS) that might not be accessible by some  
generic local user (such as root). Thus: the clean process for files  
in $HOME has to run as x2go user and should not delay any  
communication between server and client.

My suggestion is to fork such a cleanup daemon in user space that  
intellegently cleans up after the session has started up...

   x2gostartagent
   ... sleep for 20 seconds -> then launch x2gocleanup-session

This is only necessary once per logged in user (you do not want a  
session cleaner for each of multiple rootless applications, started on  
the server).

> While
> not perfect, x2gocreatesession (and x2goresumesession?) is rather
> something you expect to do more, as it also creates a profile folder.
> You might even want it to wait a week before it cleans up, so you can
> "debug" your session.

Indeed! Or at least have an option for that...

> Cheers
> Morty

Greetings,
Mike



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