Threading and TCP server

[Ehab Teima]

Jp Calderone <exarkun at intarweb.us> wrote in message news:<mailman.1044555974.4801.python-list at python.org>...
> On Thu, Feb 06, 2003 at 09:17:27AM -0800, Ehab Teima wrote:
> > Hello,
> > 
> > I am getting started with using threads and server. I wrote the server
> > that waits forever until it gets called from the client. The client
> > would send a command to the server to be executed on the server
> > machine(sort of rsh but with piping between the client). The server
> > would handle the client in a separate thread. The code works fine if
> > the command to be executed is short. The problem I have is when the
> > client passes something like "ls && sleep 60", the server can not
> > respond to any other client until it releases this client. Is there a
> > way to make the server alert without disconnecting the client that
> > casues the long delays.
> 
>   At least two options exist:
> 
>     Extend your use of threads to include whatever sys call (I'm assuming
> os.system()) you're passing commands to.  That is, call os.system("sleep
> 60") from a separate thread from the main server.
> 
>     Use os.popen() or os.openpty() to execute the commands, and then handle
> the resulting file objects asynchronously.

I am not sure this will work. I am already using os.popen to launch
the process. Also, the whole client request, including the popen call,
is handled on its own thread. In other words, the popen call is handle
within the client thread as well. Therefore, I do not think that
adding another thread for that specific popen call will help. The
problem disappears when I use spawnv with os.P_NOWAIT since it does
not wait for the process to finish. Any other method that waits for
the process, does trap the server.
Aside from that, openpty is only available on Unix, the code has to
work on three Unix platforms in addition to Windows.
> 
> 
>   Stepping back from the specifics and looking at the problem as a whole,
> I'd recommend using something like Twisted - http://www.twistedmatrix.com/ -
> to solve this problem.  It handles the process abstraction for you, it
> handles multiplexing clients for you, it does all the socket code, and it
> doesn't even rely on threads.
> 
> 
>   Jp
> 
> -- 
> "Pascal is Pascal is Pascal is dog meat."
>                 -- M. Devine and P. Larson, Computer Science 340