On 18/06/07, Robin Becker <[EMAIL PROTECTED]> wrote: > Wildemar Wildenburger wrote: > > Robin Becker wrote: > ......... > > > > Well I can think of a dumb way: create a temporary file during the > > transaction and have your script check for that before running its main > > body. > > > > > > I think thats the most hassle free way of doing it. > > /W > I looked at the temporary files idea, but I'm not certain about the exact > details. Normally your create a file and then remove it whilst keeping the > file > handle; that allows your program to write to it whilst guaranteeing that it > will > vanish when you die, but this has to be a named file so that the second > instance > can check for it.
Doesn't that prevent it from being already removed? My unix > experience is long, but fairly primitive. You don't need to remove the file, write anything to it, or check for prior existance :) If one process has the file open for writing, no other process can open it for writing at the same time - and this is what you are checking for! The exception that the second concurrent open/write attempt raises tells you that another instance of the script is running. This has the added advantage that should something go wrong, such as an abnormal termination or reboot, the open/write disappears and the next time the script runs everything is back to normal. HTH :) -- http://mail.python.org/mailman/listinfo/python-list
