How to schedule daily, monthly, weekly cron jobs using python cron-tab?

Question

I need to run a cron job daily, weekly, monthly using python. I did much research and decided to go with crontab. This is my configuration :

"schedule" :  {
  "name": "xyz",
  "at": "12:00:00 AM",
  "every": "1d"
  } 

Here, every can take the value of 1d, 1w, 1m for daily, weekly, monthly. It can also take values as 2d, 2w, 2m, etc. I have identified the code for daily and monthly. I am stuck with weekly. Can anyone help ?

my_cron = CronTab(user=self.user)
        for job in my_cron :
            if job.comment == self.name:
                my_cron .remove(job)
                my_cron .write()
        job = my_cron .new(
            command='sh start.sh "invoke-adapter"',
            comment=self.name)        
        job.setall(str_job_schedule)
        vmware_cron.write()

For monthly, str_job_schedule = "30 03 * */1 *" (runs every month)
For daily, str_job_schedule = "30 03 * * */1" (runs every day)
For weekly, str_job_schedule = "30 03 ? * *" 

Answer 1

I would specify which day I want:

For monthly, every 1st of the month

str_job_schedule = "30 03 1 * *"

For daily, everyday at midnight

str_job_schedule = "30 03 * * *"

For weekly, every sunday

str_job_schedule = "30 03 * * 0"

This WP page explains the format: https://en.wikipedia.org/wiki/Cron .

Answer 2

I did very similar thing and basicly created kind of scheduler. I will show you approximatly the idea

import threading
from crontab import CronTab
import time
schedules = {'Jobs': {'clean house': '* * * * *'}, {'cook': '*/5 * * * *'}} # some kind of config of your jobs

while True:
    time.sleep(11)
    for job in schedules['Jobs']:
        entry = CronTab(schedules['Jobs'][job])
        if entry.next() < 9:
            # if the job is going to happen in less than 10s
            # run thread which will execute after time.sleep(entry.next())
            threading.Thread(target = execute,args=(job,)).start()