Try and Except catch all errors, except for sys.exit()
I have created a function, but errors could pop up. That is why I want to use exceptions to generalize all errors into the same message.
However, this function contains multiple sys.exit() calls.
As a result, I would like to have my code jump into the except handler if an error was raised, unless it is caused by sys.exit(). How do I do this?
try:
myFunction()
except:
print "Error running myFunction()"
def myFunction():
sys.exit("Yolo")
Asked by: John911 | Posted: 27-01-2022
Answer 1
You should not use a blanket except, but instead catch Exception:
try:
myFunction()
except Exception:
print "Error running myFunction()"
The Exception class is the base class for most exceptions, but not SystemExit. Together with GeneratorExit and KeyboardInterrupt, SystemExit is a subclass of BaseException instead:
BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
+-- Everything else
Exception on the other hand is also a subclass of BaseException, and the rest of the Python exception classes are derived from it rather than BaseException directly. Catching Exception will catch all those derived exceptions, but not the sibling classes.
See the Exception Hierarchy.
As such you should only very rarely use a blanket except: statement. Alway try to limit an except handler to specific exceptions instead, or at most catch Exception.
Answer 2
While there is validity in knowing what exception you are trying to catch, there are blanket options. The following uses the sys library to catch all exceptions and traceback to process the exception message. This first block of code is a bit redundant but demonstrates how that exception can be assigned to a variable and interpreted. Keep in mind that an exception is returned as a tuple with error class, message, & traceback. As follows:
import sys
import traceback
try:
myfunction()
except Exception as e:
e = sys.exc_info()
print('Error Return Type: ', type(e))
print('Error Class: ', e[0])
print('Error Message: ', e[1])
print('Error Traceback: ', traceback.format_tb(e[2]))
Often, you're just looking for the error class and that can be done very succinctly. (Note the blanket except.)
try:
myFunction() except:
print('Error: ', sys.exc_info()[0])
Happy error catching!
Answered by: Brianna975 | Posted: 28-02-2022Similar questions
Python sys.exit() help?
I am working in Python and am trying to have a line of code execute and after it executes I am calling sys.exit() to have the script itself "exit." However, it seems that sys.exit() is executing before the line of code above it executes. Below is the code I am trying to implement:
if something == True:
self.redirect('http://www.google.com/')
sys.exit()
The...
python - Issue with sys.exit() in pygame
I am learning to use Pygame, and when I use sys.exit(), I run into a problem. Here is the code:
import pygame, sys,os
from pygame.locals import *
pygame.init()
window = pygame.display.set_mode((468, 60))
pygame.display.set_caption('Game')
screen = pygame.display.get_surface()
file_name = os.path.join("data","image.bmp")
surface = pygame.image.load(file_name)
screen.blit(surface, (0,0)...
How to use sys.exit() in Python
player_input = '' # This has to be initialized for the loop
while player_input != 0:
player_input = str(input('Roll or quit (r or q)'))
if player_input == q: # This will break the loop if the player decides to quit
print("Now let's see if I can beat your score of", player)
break
if player_input != r:
print('invalid choice, try again')
if player_input ==r:
roll...
python - Is it possible for a unit test to assert that a method calls sys.exit()?
I have a Python 2.7 method that sometimes calls
sys.exit(1)
Is it possible to make a unit test that verifies this line of code is called when the right conditions are met?
linux - Python Daemon Thread Clean Up Logic on Abrupt sys.exit()
Using Linux and Python 2.7.6, I have a script that uploads lots of files at one time. I am using multi-threading with the Queue and Threading modules.
I implemented a handler for SIGINT to stop the script if the user hits ctrl-C. I prefer to use daemon threads so I don't have to clear the queue, which would require alot of re-writing code to make the SIGINT handler have access to the Queue object since the handler...
python script doesn't stop with sys.exit()
In my Program I have a GUI with a progressbar. The value of the progressbar is a variable of a other script so I created an update function that refreshes the GUI so I have a moving progressbar.
def update(lblhowfar,bar,window,Zeitraum,auswahl,testprogress):# update function to refresh the progress bar and the percentage label
while rd.filtering_done==False:
Progress=int(rd.Zähler/rd.Nenner)
...
python - How do I use sys.exit()?
How do I use sys.exit() in this while loop?
The user inputs 3 sides of a triangle. If it is a right angle Pythagorean triangle, then it prints.
If the user enters "0", the program ends.
Also, is there a better way to write the infinite while loop besides using count = 0 and never incrementing it?
def pythagoreanTriple():
count = 0
print("input 3 sides of a triang...
python - I can't catch sys.exit()
I want to prevent a python program to quit when it calls sys.exit, but the following solution doesn't work:
Python 3.9.1 (tags/v3.9.1:1e5d33e, Dec 7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)] on win32
>>> import sys
>>> try:
... sys.exit()
... except SystemExit:
... print('asd')
...
Process finished with exit code 0
I've also tried BaseExcep...
python - using sys.exit() and heroku threw an error
2022-02-21T01:07:54.352381+00:00 heroku[router]: at=error code=H14 desc="No web processes running" method=GET path="/" host=_botname.herokuapp.com request_id=88df74f6-a5a1-4ee9-a0a5-c98a22a60949 fwd="115.66.143.26" dyno= connect= service= status=503 bytes= protocol=https
2022-02-21T01:07:54.988568+00:00 heroku[router]: at=error code=H14 desc="No web processes running" method=...
python - Unittest causing sys.exit()
No matter what I do sys.exit() is called by unittest, even the most trivial examples. I can't tell if my install is messed up or what is going on.
IDLE 1.2.2 ==== No Subprocess ====
>>> import unittest
>>>
>>> class Test(unittest.TestCase):
def testA(self):
a = 1
self.assertEqual(a,1)
>>> unittest.main()
option -n not recognized
Usa...
python - Handle sys.exit() in cherrypy service
When you start/stop a python cherrypy service (compiled with py2exe), this works fine When I get a sys.exit() call (from my error handler), cherrypy quits, but the service remains hanging.
Code:
import cherrypy
import win32serviceutil
import win32service
import sys
SERVICE = None
class HelloWorld:
""" Sample request handler class. """
def __init__(self):
self.iVal = ...
linux - How to bypass the 0-255 range limit for sys.exit() in python?
In python (on a Linux system), I'm launching a command using os.system() and retrieving the return code. If that return code is different from 0, I would like to make the program exit with that same return code. So I wrote:
ret = os.system(cmd)
if ret != 0:
print "exit with status %s" % ret
sys.exit(ret)
When the return code is lower than 256, it works fine, but when it'...
Python sys.exit() help?
I am working in Python and am trying to have a line of code execute and after it executes I am calling sys.exit() to have the script itself "exit." However, it seems that sys.exit() is executing before the line of code above it executes. Below is the code I am trying to implement:
if something == True:
self.redirect('http://www.google.com/')
sys.exit()
The...
mocking - How to get around "sys.exit()" in python nosetest?
It seems that python nosetest will quit when encountered sys.exit(), and mocking of this builtin doesn't work.
import - python: Importing scipy.io seems to prevent sys.exit() to work properly
Under Windows, executing the following Python script I get an ERRORLEVEL of 0 instead of the expected 2.
import sys
import scipy.io
sys.exit(2)
If I remove the import scipy.io, I got the correct ERRORLEVEL of 2...
Any idea why importing scipy.io cause such an issue?
PS: windows 7, python 2.72, scipy 0.10.1
Calling help(sys.exit) just before the sys.exit call return...
python - Issue with sys.exit() in pygame
I am learning to use Pygame, and when I use sys.exit(), I run into a problem. Here is the code:
import pygame, sys,os
from pygame.locals import *
pygame.init()
window = pygame.display.set_mode((468, 60))
pygame.display.set_caption('Game')
screen = pygame.display.get_surface()
file_name = os.path.join("data","image.bmp")
surface = pygame.image.load(file_name)
screen.blit(surface, (0,0)...
python - Why are the methods sys.exit(), exit(), raise SystemExit not working?
I need an alternative to kill the python script while inside a thread function. My intention is killing the server when the client enters a 0... Is this not working because the threads haven't been terminated? Here is my code:
socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
print 'Socket created'
try:
socket.bind((HOST, PORT))
except socket.error, message:
print 'Bind statement failed. ...
How to use sys.exit() in Python
player_input = '' # This has to be initialized for the loop
while player_input != 0:
player_input = str(input('Roll or quit (r or q)'))
if player_input == q: # This will break the loop if the player decides to quit
print("Now let's see if I can beat your score of", player)
break
if player_input != r:
print('invalid choice, try again')
if player_input ==r:
roll...
python - Is it possible for a unit test to assert that a method calls sys.exit()?
I have a Python 2.7 method that sometimes calls
sys.exit(1)
Is it possible to make a unit test that verifies this line of code is called when the right conditions are met?
Still can't find your answer? Check out these communities...
PySlackers | Full Stack Python | NHS Python | Pythonist Cafe | Hacker Earth | Discord Python