I'm finding multiple problems getting cron to start the scheduler. Here's
the cron line:
@reboot dummyuser python web2py.py -K utility
...but it does not work without modifying web2py source.
First, let's get an easy bug out of the way. The web2py book gives this
example for @reboot:
@reboot * * * * root *mycontroller/myfunction
But those asterisks shouldn't be there for @reboot tasks. Can we remove
them from the book?
Now, when I put that line into my crontab and run web2py, it gives me this
error:
web2py Web Framework
Created by Massimo Di Pierro, Copyright 2007-2011
Version 1.99.7 (2012-03-04 22:12:08) stable
Database drivers available: SQLite3, pymysql, psycopg2, pg8000, CouchDB,
IMAP
Starting hardcron...
please visit:
http://192.168.56.101:8000
use "kill -SIGTERM 10818" to shutdown the web2py server
Exception in thread Thread-2:
Traceback (most recent call last):
File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner
self.run()
File "/home/toomim/projects/utility/web2py/gluon/newcron.py", line 234,
in run
shell=self.shell)
File "/usr/lib/python2.6/subprocess.py", line 633, in __init__
errread, errwrite)
File "/usr/lib/python2.6/subprocess.py", line 1139, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
This is an error in subprocess.Popen. I inserted some print statements and
found that it's calling it like this:
subprocess.Popen('python web2py.py -K utility')
This is incorrect, it should be:
subprocess.Popen(['python', 'web2py.py' '-K' 'utility'])
I was able to make it work by adding a call to split(), as you can see here
(in newcron.py: cronlauncher.run()):
def run(self):
import subprocess
proc = subprocess.Popen(self.cmd.split(),
But I do not understand how anybody could have made this work before,
without adding a split() call? And what confuses me further is that there
is an explicit join() call in the __init__() method that runs immediately
beforehand, as if we really did NOT want to have lists:
elif isinstance(cmd,list):
cmd = ' '.join(cmd)
So does cron @reboot work for anybody running a script? It seems impossible
for it to work right now. Is this a bug?
Finally, it would be great if we did not have to pass in a dummy user to
each cron line that does nothing...
