[SOLVED] Python Script Runs Perfectly on Bash but Fails at Cronjob

browny redandy · 07-29-2015, 02:24 AM

Hi,

I have been surfing for almost two days to look for related problem and solutions. But to no avail, I have not found any suitable ones. Any help is greatly appreciated!!

I am using Raspian on Rpi. I am running a python script pi_surveillance.py that requires an activation of the virtual environment cv before the script can work. I am implementing it on cronjob as I wanted it to run at every reboot.

The virtual environment is created for pi user. Hence, what I did was to create a launcher.sh script to activate the environment and run the python script.

Code:

#!/bin/bash
# launcher.sh
# activate the cv environment ,then execute
# python script


source ~/.profile 
workon cv

python  /home/pi/pi_surveillance.py --conf conf.json

For cronjob, what I did was,

Code:

sudo crontab -e

At the last line of the crontab, I added a line:

Code:

@reboot sudo -u pi /home/pi/launcher.sh >/home/pi/logs/cronlog 2>&1

But, it did not work out and reflected this on my cron log.

Code:

Traceback (most recent call last):
  File "/home/pi/pi_surveillance.py", line 28, in <module>
    conf = json.load(open(args["conf"]))
IOError: [Errno 13] Permission denied: 'conf.json'

I am really desperate for a solution or a direction to where I should work towards!!

goumba · 07-29-2015, 03:49 AM

Use a full path to the conf file in your scripts, and give it a try. cron uses a minimal environment, so the script may not know where to find files.

Code:

#!/bin/bash
# launcher.sh
# activate the cv environment ,then execute
# python script

source $HOME/.profile 
workon cv

python  $HOME/pi_surveillance.py --conf $HOME/conf.json

browny redandy · 07-29-2015, 04:19 AM

How do one find the full path?
I tried

Code:

$ find "$(cd ..; pwd)" -name "conf.json"

It gives me

Code:

/home/pi/conf.json

The other qn is do I replace /home/pi with $HOME?

Sorry for the noob question. I am new to this.

Thanks!

goumba · 07-29-2015, 04:53 AM

Quote:

Originally Posted by browny redandy

How do one find the full path?
I tried

Code:

$ find "$(cd ..; pwd)" -name "conf.json"

It gives me

Code:

/home/pi/conf.json

There you go, you have the full path.

Quote:

The other qn is do I replace /home/pi with $HOME?

BTW,

Code:

find .. -name "conf.json"

would have been fine.

Sorry for the noob question. I am new to this.

Thanks!

$HOME and the tilde ~ are synonymous. I tend to use $HOME as it's a little clearer, doesn't get lost in other text. Either will expand to the user's home directory. in this case, /home/pi.

browny redandy · 07-29-2015, 05:18 AM

Thanks for your guidance so far! It worked well.