How to pass an error exit code from a python script to the KSH script that calls it?

Question

I have a python script that is called by a korn shell script. If the python script runs into an error, the korn shell script still exits with 0. How to a get the python script to tell the ksh that it didn't terminate correctly?

The rapper script looks like this:

python2.7 python_script.py ${inargument} >> ${log_file}  2>&1

exit_code=$?                             

if [ ${exit_code} -ne 0 ]
   then
   echo "Python script failed" >> ${log_file}
fi

Answer 1

I'm not sure about KSH, but this is how you get python to return a non-zero return value, I assume KSH can detect and deal with that.

import sys

retCode = 5
sys.exit(retCode)

or

retCode = -128
raise SystemExit(retCode)

Answer 2

Wrap your whole script in a try block and in catch write the error to an out put file. Than in your ksh you can go read that output file and do what ever it is you need to do.

here is some pseudo code.

rm opFile
python yourSript.py
if opFile != blank:
   process log file... 
   start cat runlog.m | more

Answer 3

I could not comment because of reputation, but you absolutely could use the code from nephim comment.

1) just put the first of nephim's code in test.py (chmod 700 test.py)

2) this ksh script run test.py :

#!/usr/bin/ksh

./test.py

exit $?

3) And this is example from command line

> ./test.ksh 
> echo $?
5

P.S.: You should chmod 700 test.ksh as well.

P.P.S : Probably I misunderstood your question. If your python script exits before it reach the end (and so it don't execute sys.exit(codeRet) command), in this case you should use try..execpt construction.

try :
    <some code>
except <Error to Catch>:
    sys.exit(codeRet)

As explained here : Python: about catching ANY exception you could even catch all of exceptions :

try:
    do_something()
except:
    print "Caught it!"

But as explained : "You can but you shouldn't"

Update: @AlexKinman I think there is some problem with your python... as mentioned by tripleee could it be some wrapper? Could you give a return of which python2.7

Here my tests :

$# cat wrong_test.ksh

#!/bin/ksh

log_file=log.txt

python -c 'raise Exception("foo")' >> ${log_file}  2>&1

exit_code=$?                             

if [ ${exit_code} -ne 0 ]
   then
   echo "Python script failed" >> ${log_file}
fi

$# cat log.txt Traceback (most recent call last): File "", line 1, in Exception: foo Python script failed

$# cat good_test.ksh

#!/bin/ksh

log_file=log1.txt

python -c 'print "Hello"' >> ${log_file}  2>&1

exit_code=$?                             

if [ ${exit_code} -ne 0 ]
   then
   echo "Python script failed" >> ${log_file}
fi

$# cat log1.txt
Hello