Crontab error : Windows can not find the specified file

Question

I am trying to use this example script to test crontab in python:

from crontab import CronTab

tab = CronTab(user='www',fake_tab='True')
cmd = '/var/www/pjr-env/bin/python /var/www/PRJ/job.py'
cron_job = tab.new(cmd)
cron_job.minute().every(5)
#writes content to crontab
tab.write()
print tab.render()

It returns with an error 'fake_tab' not defined. If i remove this parameter and call the function
like this: CronTab(user='www'). I returns the following error :

Traceback (most recent call last):
File "<pyshell#8>", line 1, in <module>
tab = CronTab(user='www')
File "C:\Python27\lib\site-packages\crontab.py", line 160, in __init__
self.read(tabfile)
File "C:\Python27\lib\site-packages\crontab.py", line 183, in read
p = sp.Popen(self._read_execute(), stdout=sp.PIPE)
File "C:\Python27\lib\subprocess.py", line 711, in __init__
errread, errwrite)
File "C:\Python27\lib\subprocess.py", line 948, in _execute_child
startupinfo)
WindowsError: [Error 2] The system cannot find the file specified

Does any one know, what am I missing?

Answer 1

The easiest way I found to make crontab find my job was:

In settings.py (I'm using django) I defined these variables:

CRONTAB_EXECUTABLE='C:/Users/myuser/myvirtualenv/Lib/site-packages/django_crontab/crontab.py'
CRONTAB_DJANGO_PROJECT_NAME='myproject'
CRONTAB_DJANGO_MANAGE_PATH='C:/Users/myuser/myvirtualenv/myproject/manage.py'
CRONTAB_PYTHON_EXECUTABLE='C:/Users/myuser/AppData/Local/Programs/Python/Python36-32/pythonw.exe'

Pay attention to the slash. It must be leaned to the right or it causes a syntax error.

By this way crontab will find the job or whatever you are trying to execute. In my case I was trying:

C:\Users\bsi\mlearning3\src>python manage.py crontab add

Answer 2

As the author of python-crontab I can report that the documentation has been updated. It's clear ineffective given the number of people puzzled over what manual means.

If you do this:

mem_cron = CronTab(tab="""
  * * * * * command # comment
""")

You should have a memory only crontab. Same if you do a file as a crontab:

file_cron = CronTab(tabfile='filename.tab')

I'm always looking to improve the code and documentation, so please do email me.

Answer 3

I think that Crontab is a Unix/Linux concept. Not sure if it can work under windows. This Page says "Windows support works for manual crontabs only". Not sure what he means by that though.