Nagios script to check file size with human readable input and output (in python). Similar to ./check_files.pl -F file.txt -s 5000000,10000000

check_file_size.py

import argparse,os
#Return OK, Warning, or Critical for nagios to parse.
argparser = argparse.ArgumentParser(description='Nagios script to check file size with human readable input and output (in python).  Similar to  ./check_files.pl -F file.txt -s 5000000,10000000',epilog="Thanks, Hope you like it. -Ryan")
argparser.add_argument('--missingfileok','-m',action='store_true',help='If the file does not exist return OK.')
argparser.add_argument('--file','-f',type=str,required=True,help='Pass in full path and file name i.e. --file /test/123/filename.txt ')
argparser.add_argument('--critical','-c',type=str,required=True,help='K,M, or G, defaults to bytes')
argparser.add_argument('--warning','-w',type=str,required=True,help='K,M, or G, defaults to bytes')
args = argparser.parse_args()

suffixes = ['K', 'M', 'G', 'T']

def CheckFileExists(pathandfilename):
  return os.path.isfile(pathandfilename)

def GetFileSize(pathandfilename):
  return os.path.getsize(pathandfilename)

def ConvertFileSizeToBKMGT(size):
  sizes = {}
  sizes["B"] = size # occupies suffixindex 0
  suffixIndex = 0
  while suffixIndex < 4:
    suffixIndex += 1  # increment the index of the suffix
    size = size / 1024.0  # apply the division
    sizes[suffixes[suffixIndex-1]] = size
  return sizes

def RepresentsFloat(s):
  try:
    float(s)
    return True
  except ValueError:
    return False

def SplitValueandSuffix(worcinput):
  if RepresentsFloat(worcinput):
    return worcinput,"B"
  else:
    inputvalue = worcinput.strip(worcinput[-1])
    if RepresentsFloat(inputvalue) and worcinput[-1].upper() in suffixes:
      return float(inputvalue), worcinput[-1].upper()

def main(args):
  if CheckFileExists(args.file):
    filesizeinbytes = GetFileSize(args.file)
    bkmgt = ConvertFileSizeToBKMGT(filesizeinbytes)
    warning = SplitValueandSuffix(args.warning) # for 20K returns a tuple  (20,K)
    critical = SplitValueandSuffix(args.critical)
    if bkmgt[critical[1]] >= critical[0]:
      print("Critical - File Size is ", round(bkmgt[critical[1]], 2), critical[1])
    elif bkmgt[warning[1]] >= warning[0]:
      print("Warning - File Size is ",round(bkmgt[warning[1]],2), warning[1])
    else:
      print("OK - File Size is ", round(bkmgt[warning[1]],2), warning[1])
  elif args.missingfileok:
    print("OK - Missing File")
  else:
    print("Critical - Missing File")



if __name__ == "__main__":
  try:
    main(args)
  except(Exception):
    raise
  else:
    pass
  finally:
    pass