OpenVPN Stats DB Update

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os, sys, pickle

STATUS = "/var/log/openvpn-status.log" #location of open vpn status file
#STATUS = "openvpn-status.log"
db_folder = "db" #folder for storing data

sizes = [
    (1<<50L, 'PB'),
    (1<<40L, 'TB'),
    (1<<30L, 'GB'),
    (1<<20L, 'MB'),
    (1<<10L, 'KB'),
    (1,       'B')
]

def byte2str(size):
    for f, suf in sizes:
        if size >= f:
            break

    return "%.2f %s" % (size / float(f), suf)

def read_stats():
    status_file = open(STATUS, 'r')
    stats = status_file.readlines()
    status_file.close()

    hosts = []

    headers = {
        'cn':    'Common Name',
        'virt':  'Virtual Address',
        'real':  'Real Address',
        'sent':  'Sent',
        'recv':  'Received',
        'since': 'Connected Since'
    }

    for line in stats:
        cols = line.split(',')

        if len(cols) == 5 and not line.startswith('Common Name'):
            host  = {}
            host['cn']    = cols[0]
            host['real']  = cols[1].split(':')[0]
            host['recv']  = int(cols[2])
            host['sent']  = int(cols[3])
            host['since'] = cols[4].strip()
            hosts.append(host)

        if len(cols) == 4 and not line.startswith('Virtual Address'):
            for h in hosts:
                if h['cn'] == cols[1]:
                    h['virt'] = cols[0]


    fmt = "%(cn)-25s %(virt)-18s %(real)-15s %(sent)13s %(recv)13s %(since)25s"

    print fmt % headers
    print "\n".join([fmt % h for h in hosts])
    return hosts

def getScriptPath(): #gets script directory
    return os.path.dirname(os.path.realpath(sys.argv[0]))

def update_log(cn,vhost):
    dhosts = []
    fn = os.path.join(getScriptPath(), db_folder, cn) + ".log"
    if os.path.exists(fn):
        old_host = pickle.load(open( fn, "rb" )) #read data from file
        print old_host

        if old_host[1]['since'] == vhost['since']:
            dhosts.append(old_host[0])
            print "same session"
            dhosts.append(vhost)
        else:
            old_host[0]['recv'] += old_host[1]['recv']
            old_host[0]['sent'] += old_host[1]['sent']
            old_host[0]['since'] = old_host[1]['since']
            old_host[0]['real'] = old_host[1]['real']
            dhosts.append(old_host[0])
            dhosts.append(vhost)

            print "new session"
            print old_host[1]['since']
        pickle.dump(dhosts, open( fn, "wb" )) # save data to file
    else:
        dhosts.append(vhost)
        dhosts.append(vhost)
        pickle.dump(dhosts, open( fn, "wb" ))

    return

if __name__ == '__main__':
    hosts = read_stats()
    for h in hosts:
        print h['cn']
        update_log(h['cn'],h)