Is it possible to create never crashing python code with exception handling?

Question

I wonder if the below python code (specifically http server) ever crashes? Assuming that there is no grammer error in any of the library code(already compiled), what I think that handling the exceptions in a while loop should be sufficient for this code not to crash anytime. I tried the below code for a while and never crashed, but I wonder if theoretically or practically possible for this program to crash?

while True:
    try:

        server = HTTPServer(('', PORT_NUMBER), myHandler)
        server.serve_forever()

    except:
        try:
           server.socket.close()
        except:
            pass

The actual reason I am asking this question that I don't want to deal with UNIX staff to watch the process and restart it if it crashes. Is the above solution sufficient? Thanks.

Socket.close() could raise an exception in some edge cases. — Klaus D.
– Klaus D., Commented Mar 31, 2020 at 6:20
I edited to code in question, so please forget about server.socket.close() line — eral
– eral, Commented Mar 31, 2020 at 6:48
While you will now stay inside the loop, it is not guaranteed that the code really works. If it raises an exception it will be stuck in a loop without ever working. And no tool (like supervisord explained below) will notice. It will most likely just occupy one CPU core. — Klaus D.
– Klaus D., Commented Mar 31, 2020 at 6:52

azizbek masharibov · Accepted Answer · 2020-03-31 06:27:04Z

0

If "except" block has worng code, it can crash cause of it. I mean, something like that:

# path/to/py3
FOO = [1,2,3]
try:
  # index out of bound, try block has error, so it goes ahead and executes except-block
  print(FOO[4])
except:
  # if there is some kind of error, like Syntax error, program can crash
  print "Index out of bound!"
  print("2"+2)
  print(FOO["BAR"])

but if exception block has the correct logic too, then programm should work without crashing

answered Mar 31, 2020 at 6:27

azizbek masharibov

1137 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

eral Over a year ago

Except clause has only this line and one can assume it never throws: server.socket.close()

tonyl7126 · Accepted Answer · 2020-03-31 06:33:40Z

0

Like Klaus D. already mentioned in his comment, there can be cases where the socket close code in your except block crashes. You could optionally also throw a try except around that as well...

Another option is to use something like this (no UNIX involved):

http://supervisord.org/

It's easy to run and will automatically restart your program if it crashes.

answered Mar 31, 2020 at 6:33

tonyl7126

1,5783 gold badges14 silver badges19 bronze badges

Collectives™ on Stack Overflow

Is it possible to create never crashing python code with exception handling?

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related