WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH] suggested change in exception-handling style of user

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] [PATCH] suggested change in exception-handling style of user-space tools
From: Daniel Miles <daniel.t.miles@xxxxxx>
Date: Tue, 23 May 2006 10:20:21 -0600
Delivery-date: Tue, 23 May 2006 09:20:56 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
In the tools/python/xen/xm directory, main.py has good error messages
that let the user know what failed; the other 'sub-command' classes
don't always have such good messages which can lead to some inexplicable
failures by the user-space tools.

Standard practice is to except each error by type and react accordingly
but in case the programmer does not anticipate a type of exception,
standard practice is to put in a catch-all exception handler that
excepts an 'Exception' object. Often in this case, the system will print
out the exception and exit.

If a sub-command excepts an 'Exception' object and the error is not
specific to that sub-command, it should pass the exception up for main
to handle. Especially in light of the fact that there is already a broad
collection of good error messages in main, I believe that this will lead
to better code re-use in the form of a one-stop-shop for error messages.
In this patch I've changed only one of the general case exception
handlers in one of the sub-commands (xm create) as a test-balloon to see
if the xen community will accept future patches of this type.

Singed-off-by: Daniel Miles <daniel.t.miles@xxxxxx>

Attachment: exception_handling.patch
Description: Text Data

Attachment: signature.asc
Description: This is a digitally signed message part

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] [PATCH] suggested change in exception-handling style of user-space tools, Daniel Miles <=