python does not release filehandles to logfile

Question

I have an application which has to run a number of simulation runs. I want to setup a logging mechanisme where all logrecords are logged in a general.log, and all logs for a simulation run go to run00001.log, .... For this I have defined a class Run. in the __init__() a new filehandle is added for the runlog.

The problem is that the logfiles for the runs never get released, so after a number of runs the available handles are exhausted and the run crashes.

I've set up some routines to test this as follows

main routine

import Model try:     myrun = Model.Run('20130315150340_run_49295')     ha = raw_input('enter')     myrun.log.info("some info") except:     traceback.print_exc(file=sys.stdout)  ha = raw_input('enter3') 

The class Run is defined in module Model as follows

import logging class Run(object):      """ Implements the functionality of a single run. """     def __init__(self, runid):         self.logdir="."         self.runid          = runid         self.logFile        = os.path.join(self.logdir , self.runid + '.log')         self.log            = logging.getLogger('Run'+self.runid)         myformatter         = logging.Formatter('%(asctime)s %(name)-12s %(levelname)-8s %(message)s')         myhandler      = logging.FileHandler(self.logFile)         myhandler.setLevel(logging.INFO)         myhandler.setFormatter(myformatter)         self.log.addHandler(myhandler)  

Then I use the program process explorer to follow the filehandlers. And I see the runlogs appear, but never disappear.

Is there a way I can force this?

Answer 1

You need to call .close() on the filehandler.

When your Run class completes, call:

handlers = self.log.handlers[:] for handler in handlers:     handler.close()     self.log.removeHandler(handler) 

Answer 2

You can also shutdown the logging completely. In that case, file handles are being released:

logging.shutdown() 

It closes opened handles of all configured logging handlers.

I needed it to be able to delete a log file after a unit test is finished and I was able to delete it right after the call to the logging.shutdown() method.