Class GuardedFunctionFactory

source code

object --+
         |
        GuardedFunctionFactory

a class for making functions safe for cron-like executions.

The main method is makeGuarded. It introduces a lock protecting against double execution (if that were to happen, the execution is suppressed with a warning; of course, if you fork something into the background, that mechanism no longer works). The stuff is run in a thread, and exceptions caught. If anything goes wrong during execution, a mail is sent to the administrator.

Note that, in contrast to cron, I/O is not captured (that would be difficult for threads; we don't want processes because of the potential trouble with database connections).

There's a module-private instance of this that's used by Execute.