Maintaining Logging and/or stdout/stderr in Python Daemon

Question

Every recipe that I\'ve found for creating a daemon process in Python involves forking twice (for Unix) and then closing all open file descriptors. (See http://www.jejik.com

Answer 1

We just had a similar issue, and due to some things beyond my control, the daemon stuff was separate from the stuff creating the logger. However, logger has a .handlers and .parent attributes that make it possible with something like:

    self.files_preserve = self.getLogFileHandles(self.data.logger)

def getLogFileHandles(self,logger):
    """ Get a list of filehandle numbers from logger
        to be handed to DaemonContext.files_preserve
    """
    handles = []
    for handler in logger.handlers:
        handles.append(handler.stream.fileno())
    if logger.parent:
        handles += self.getLogFileHandles(logger.parent)
    return handles