Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: Ganesh Pal <ganesh1pal@gmail.com>
Newsgroups: comp.lang.python
Subject: sys.exit(1) vs raise SystemExit vs raise
Date: Tue, 12 Apr 2016 18:20:54 +0530
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Xref: csiph.com comp.lang.python:106905

I m on python 2.7 and Linux ,  I have a simple code  need suggestion if  I
 I could replace sys.exit(1) with raise  SystemExit .


==Actual code==

def main():
    try:
        create_logdir()
        create_dataset()
        unittest.main()
    except Exception as e:
        logging.exception(e)
        sys.exit(EXIT_STATUS_ERROR)

if __name__ == '__main__':
    main()

==Changed Code==


def main():
    try:
        create_logdir()
        create_dataset()
        unittest.main()
    except Exception as e:
        logging.exception(e)
        raise SystemExit

if __name__ == '__main__':
    main()


2. All the functions in try block have exception bubbled out using raise

   Example for create_logdir() here is the function definition

def create_logdir():

    try:
        os.makedirs(LOG_DIR)
    except OSError as e:
        sys.stderr.write("Failed to create log directory...Exiting !!!")
        raise
    print "log file: " + corrupt_log
    return True

def main():
    try:
        create_logdir()
    except Exception as e:
        logging.exception(e)
        raise SystemExit

(a) In case if create_logdir() fails we will get the below error ,is
this fine or do I need to improve this code.

Failed to create log directory...Exiting !!!ERROR:root:[Errno 17] File
exists: '/var/log/dummy'

Traceback (most recent call last):
  File "corrupt_test.py", line 245, in main
    create_logdir()
  File "corrupt_test.py", line 53, in create_logdir
    os.makedirs(LOG_DIR)
  File "/usr/local/lib/python2.7/os.py", line 157, in makedirs
OSError: [Errno 17] File exists: '/var/log/dummy'


3. Can I have just raise , instead of SystemExit or sys.exit(1) . This
looks wrong to me

  def main():

    try:
        create_logdir()
    except Exception as e
        logging.exception(e)
        raise

 Regards,

Ganesh