python circular buffer log file

py

import random

indicator = 0
maxline = 30

def readSeek(file_ptr):
   file_ptr.seek(0,0)
   ind_str = file.readline()
   return int(ind_str)

def calcSeek():
   return (indicator*8)

def writeSeek(file_ptr, ind):
   file_ptr.seek(0,0)
   line = "%6d\n" % (ind)
   file.write(line)
   
print("opening file")
file = open("test.txt","r+")
indicator = readSeek(file)
print(str(indicator))
indicator += 1
if indicator > maxline:
   print("indicator overflow, wrappning around!")
   indicator = 0
else:
   print(str(indicator))
file.seek(calcSeek(),0)
line = "%6d\n" % (random.randint(0,0xFFFF))
file.write(line)
writeSeek(file,indicator)
print("closing file")
file.close()