stage3

#!/usr/bin/python
from hashlib import md5
import sys
import os

import cPickle
import re
DEBUG = 1

def dprint(string):
    if DEBUG:
        print string

exitstatus = 0
log_file = sys.argv[1]
regex = sys.argv[2]
c_file = "/tmp/grep_{0}.txt".format(md5("{0} {1}".format(log_file, regex)).hexdigest())
if os.path.isfile(c_file):
    with file(c_file, 'rb') as f:
        cursor = cPickle.load(f)
else:
    with file(log_file, 'r') as f:
        f.seek(0, 2)
        new_cursor = f.tell()
    with file(c_file, 'wb') as f:
        dprint("No cursor found, saving {0}".format(new_cursor))
        cPickle.dump(new_cursor, f)
    sys.exit(0)

with file(log_file, 'r') as f:
    dprint("Starting from {0}".format(cursor))
    f.seek(cursor)
    for l in f:
        if re.match(regex, l):
            dprint('keyword is found!')
            exitstatus = 1
            break
    f.seek(0, 2)
    new_cursor = f.tell()
with file(c_file, 'wb') as f:
    dprint("saving cursor {0}".format(new_cursor))
    cPickle.dump(new_cursor, f)

sys.exit(exitstatus)