Python subprocess call through crontab not working












0















I am using a python 3.6 script in a Raspberry Pi Zero W that contains the following lines:



import subprocess

result = subprocess.run(['which', 'node'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)

nodeCmd = result.stdout.decode("utf-8").replace('n', '')

print(nodeCmd)

result = subprocess.run([nodeCmd, './script.js'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)


The script tries to find the node binary and make a call to a js script. When ran manually, the program works OK, but when I schedule the call through crontab, the nodeCmd variable appears blank (instead of /usr/local/bin/node) and I get the following error:



[Errno 13] Permission denied: ''


What is going on here? Is this a permissions issue?










share|improve this question























  • please check stackoverflow.com/questions/39777345/…

    – Sach
    Nov 23 '18 at 9:24











  • What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

    – JoseKilo
    Nov 23 '18 at 9:25











  • @JoseKilo /usr/local/bin/node

    – derkomai
    Nov 23 '18 at 9:29











  • @Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

    – derkomai
    Nov 23 '18 at 9:30
















0















I am using a python 3.6 script in a Raspberry Pi Zero W that contains the following lines:



import subprocess

result = subprocess.run(['which', 'node'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)

nodeCmd = result.stdout.decode("utf-8").replace('n', '')

print(nodeCmd)

result = subprocess.run([nodeCmd, './script.js'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)


The script tries to find the node binary and make a call to a js script. When ran manually, the program works OK, but when I schedule the call through crontab, the nodeCmd variable appears blank (instead of /usr/local/bin/node) and I get the following error:



[Errno 13] Permission denied: ''


What is going on here? Is this a permissions issue?










share|improve this question























  • please check stackoverflow.com/questions/39777345/…

    – Sach
    Nov 23 '18 at 9:24











  • What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

    – JoseKilo
    Nov 23 '18 at 9:25











  • @JoseKilo /usr/local/bin/node

    – derkomai
    Nov 23 '18 at 9:29











  • @Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

    – derkomai
    Nov 23 '18 at 9:30














0












0








0








I am using a python 3.6 script in a Raspberry Pi Zero W that contains the following lines:



import subprocess

result = subprocess.run(['which', 'node'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)

nodeCmd = result.stdout.decode("utf-8").replace('n', '')

print(nodeCmd)

result = subprocess.run([nodeCmd, './script.js'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)


The script tries to find the node binary and make a call to a js script. When ran manually, the program works OK, but when I schedule the call through crontab, the nodeCmd variable appears blank (instead of /usr/local/bin/node) and I get the following error:



[Errno 13] Permission denied: ''


What is going on here? Is this a permissions issue?










share|improve this question














I am using a python 3.6 script in a Raspberry Pi Zero W that contains the following lines:



import subprocess

result = subprocess.run(['which', 'node'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)

nodeCmd = result.stdout.decode("utf-8").replace('n', '')

print(nodeCmd)

result = subprocess.run([nodeCmd, './script.js'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)


The script tries to find the node binary and make a call to a js script. When ran manually, the program works OK, but when I schedule the call through crontab, the nodeCmd variable appears blank (instead of /usr/local/bin/node) and I get the following error:



[Errno 13] Permission denied: ''


What is going on here? Is this a permissions issue?







node.js python-3.x cron






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 23 '18 at 9:21









derkomaiderkomai

285314




285314













  • please check stackoverflow.com/questions/39777345/…

    – Sach
    Nov 23 '18 at 9:24











  • What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

    – JoseKilo
    Nov 23 '18 at 9:25











  • @JoseKilo /usr/local/bin/node

    – derkomai
    Nov 23 '18 at 9:29











  • @Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

    – derkomai
    Nov 23 '18 at 9:30



















  • please check stackoverflow.com/questions/39777345/…

    – Sach
    Nov 23 '18 at 9:24











  • What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

    – JoseKilo
    Nov 23 '18 at 9:25











  • @JoseKilo /usr/local/bin/node

    – derkomai
    Nov 23 '18 at 9:29











  • @Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

    – derkomai
    Nov 23 '18 at 9:30

















please check stackoverflow.com/questions/39777345/…

– Sach
Nov 23 '18 at 9:24





please check stackoverflow.com/questions/39777345/…

– Sach
Nov 23 '18 at 9:24













What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

– JoseKilo
Nov 23 '18 at 9:25





What's the result of sudo which node ? Is node installed at the system level or inside $HOME/.nvm ?

– JoseKilo
Nov 23 '18 at 9:25













@JoseKilo /usr/local/bin/node

– derkomai
Nov 23 '18 at 9:29





@JoseKilo /usr/local/bin/node

– derkomai
Nov 23 '18 at 9:29













@Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

– derkomai
Nov 23 '18 at 9:30





@Sach I see, but should I give 'script.js' execution permissions? I though that was not neccesary as the script is running trhough node.

– derkomai
Nov 23 '18 at 9:30












1 Answer
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So the reason seems to be that crontab has the $PATH variable set to a different value from the user $PATH. To fix it, I just had to set the wanted value in the cron file, just above the schedule lines:



PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin





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    So the reason seems to be that crontab has the $PATH variable set to a different value from the user $PATH. To fix it, I just had to set the wanted value in the cron file, just above the schedule lines:



    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin





    share|improve this answer




























      0














      So the reason seems to be that crontab has the $PATH variable set to a different value from the user $PATH. To fix it, I just had to set the wanted value in the cron file, just above the schedule lines:



      PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin





      share|improve this answer


























        0












        0








        0







        So the reason seems to be that crontab has the $PATH variable set to a different value from the user $PATH. To fix it, I just had to set the wanted value in the cron file, just above the schedule lines:



        PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin





        share|improve this answer













        So the reason seems to be that crontab has the $PATH variable set to a different value from the user $PATH. To fix it, I just had to set the wanted value in the cron file, just above the schedule lines:



        PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 23 '18 at 18:27









        derkomaiderkomai

        285314




        285314






























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