在python中创建和删除cron作业

Question

So I have a little script I wish to run once a week. It will check on some variable and if its set, it continues running the script, if not, I want it to wait an hour and try again. If it's still not set, it'll wait 2 hours, then 4, and then give up for the week. My question is, can I do this in python? Seems like I'd have to create and delete cron jobs in python to get this to work.

Answer 1

You can't really set standard crons directly from Python. Instead, I'd set the cron to fire every hour, and in the code determine if it needs to run again (ie last successful execution is more than 7 days ago).

Answer 2

You can try using Time.sleep

if not_set:
    Time.sleep(60 * 60)        # 1 hour
if not_set:
    Time.sleep(60 * 60 * 2)    # 2 hours
if not_set:
    Time.sleep(60 * 60 * 4)    # 4 hours

Answer 3

I believe that you are looking for the at command, you can find a little tutorial here: http://www.ibm.com/developerworks/linux/library/l-job-scheduling/index.html

Basic usage:

at -f some_file_with_the_jobs.sh some_time

You can easily use relative times:

at -f some_file_with_the_jobs.sh  10pm tomorrow