[Tutor] Looking for some comments on my code segment...

[Dave (NK7Z)]

Hi,
New to Python programming, (this is part of my first Python program, 
beyond hello world), and I am working on some telnet stuff...

I would like to trap all errors, and think I am on to a start for this, 
but need a bit of help, too new to know what all I need to look for....

In the code below I am creating a telnet object for use later on in the 
program.  I believe I have it correct, but I am sure I have forgotten 
something.  It seems to run fine..

Here is the function for that:

def createtelnet():
     global tn, failcode

     try:
         tn = telnetlib.Telnet(HOST, PORT, TIMEOUT)
         logdata = "Telnet object created"
         logit(logdata)

     except socket.timeout:  # Times out, exit with error.
         failcode = 1        # Let error handler know what is happening.
         logdata = 'Unable to create telnet object, timed out'
         logit(logdata)
         exitscript()        # Leave script.

     except EOFError:
         logdata = 'Timeout reached in login.'
         logit(logdata)
         failcode = 10
         exitscript()        # Leave script.

All variables are set elsewhere, and the above code seems to work fine. 
What am I leaving out, or what don't I understand, looking for some 
comments on my code.

Later on I am accessing the connection via:

         try:
             result = tn.read_until(b"\r\n", TIMEOUT)     # Get a line.
             if result == 'b\'\'':
                 logdata = 'Stream has failed...'
                 logit(logdata)
                 failcode = 7
                 exitscript()  # Leave script.

         except socket.error:  		# If socket error-- exit.
             logdata = 'Socket Error in watchstream, at read.'
             logit(logdata)
             failcode = 8
             exitscript()  # Leave script.

         except EOFError: 		# If time out-- exit with error.
             failcode = 6  # Let error handler know what is happening.
             logdata = 'Timeout reached in watchstream'
             logit(logdata)
             exitscript()  # Leave script.

         logdata = 'Telnet read succeeded, we got:\n' + str(result)
         logit(logdata)
         error = sys.stderr
         logit(str(error))

Code to take apart the string follows this.  logit(), is a function to 
write a log as to what happened...

-- 
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources