Hiding tracebacks from end-users

[Steven D'Aprano]

I'm writing a command-line application that is meant to be relatively 
user friendly to non-technical users.

(Some wags might like to say that "user friendly" and "command-line 
application" are, by definition, contradictory. I disagree.)

Consequently, I'd like to suppress Python's tracebacks if an error does 
occur, replacing it with a more friendly error message. I'm doing 
something like this:

try:
    setup()
    do_something_useful()
except KeyboardInterrupt:
    print >>sys.stderr, "User cancelled"
    sys.exit(2)
except Exception, e:
    if expert_mode:
        # experts get the full traceback with no hand-holding.
        raise
    else:
        # print a more friendly error message
        if isinstance(e, AssertionError):
            msg = "An unexpected program state occurred"
        elif isinstance(e, urllib2.HTTPError):
            msg = "An Internet error occurred"
        else:
            # catch-all for any other exception
            msg = "An error occurred"
        print>>sys.stderr, msg
        print>>sys.stderr, e
        sys.exit(1)
else:
    sys.exit(0)



Is this a good approach? Is there another way to suppress the traceback 
and just print the error message?


-- 
Steven.