Relative paths in scripts executed by cron jobs

Question

I'm setting up my first cron job and it's not working. I think the problem may be a relative path issue.

Given cron job:

*/1 * * * * python2.7 /home/path/to/my/script/my_script.py

and my_script.py:

import sqlite3
db = sqlite3.connect('my_db.db')
cur = db.cursor()
...

How do I make sure that my_script.py looks for my_db.db in /home/path/to/my/script/ (the same directory that houses my_script.py) and not whatever directory crontab lives?

Other suggestions for troubleshooting are also welcome.

Note - I think the issue may be a path issue because when I try running my_script.py using python2.7 /home/path/to/my/script/my_script.py from any location other than /home/path/to/my/script/, I get an "unable to open database" error.

Answer 1

import sqlite3
import os

dir_path = os.path.dirname(os.path.abspath(__file__))

db = sqlite3.connect(os.path.join(dir_path, 'my_db.db'))
cur = db.cursor()
...

Remember that Python's os.path module is your best friend when manipulating paths.

Answer 2

you may want to do it a bit differently:

os.chdir(os.path.dirname(os.path.abspath(__file__)))
db = sqlite3.connect('my_db.db')

using chdir will allow to execute you script in local directory and allow you to keep all local references unchanged if you have more than one it may save you some time :)