[Tutor] Trapping High-Level Exceptions As Strings

[Tim Johnson]

By "High-Level", I mean using the except label
without any error object as a parameters, so
that I may trap any error that "falls" through
more structured traps.

Currently, I'm using something like this
code fragment below:
###############################################################
        except PrjError, err:
            print "AN INTERNAL PROGRAMMING ERROR WAS FOUND:" 
            print "Below is the report:\n"
            print err.err
            exit_code = 1
        except HaltError, err:
            print "A PROGRAM TERMINATION HAS OCCURRED:" 
            print "REASON: %s\n" % (err.err)
            exit_code = 1
        except:    
            print "WE HAVE ERRORS: Report the information below to your technical support" 
            print "----------------------------------------------------------------------------------------"
            exit_code = 1
            traceback.print_exc()
###############################################################
In the first two examples, I'm initializing an error object and
obtaining a string which I can print, or write to a logfile at
will. 

In the last example, I'm using a call to traceback.print_exc(),
which does the printing itself. The traceback information is
very good, and I want to trap that also. If I have a divide by
zero error, traceback gives me the following:
###############################################################
Traceback (most recent call last):
  File "./nwmls_cron.py", line 98, in ?
    process(args)
  File "./nwmls_cron.py", line 16, in process
    1 / 0 # test exception handling and logging
ZeroDivisionError: integer division or modulo by zero
integer division or modulo by zero
###############################################################
Which is very helpful, but I don't know how to obtain that
message as a string.

Using
   err_msg = format_list(extract_tb())
   print err_msg
# gets a string for me to print, write to file
# or both, I presume, but I only get the last
# line. Example:
"integer division or modulo by zero"

So how may I get more information, which can point
to the origin of the error?

help(traceback) indicates that extract_tb() has an
optional "tb" parameter, but I'm not clear on
how to use it.

TIA
Tim

-- 
Tim Johnson <tim at johnsons-web.com>
      http://www.alaska-internet-solutions.com