log-bin2txt

#!/usr/bin/env python3

import argparse
import sys
import struct
import time

TEXT_LOG_HEADER = 'datetime,temperature,humidity'
LOG_PREAMBLE = 'Log_v'
PREAMBLE_END_TOKEN = b'\n'
ENDIANNESS_BYTES = (78 << 24) | (185 << 16) | (219 << 8) | (110)

def get_cli_args():
  parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter, description="Convert an optimized binary log to a readable, text log.")

  parser.add_argument('binary_logfile', help="Path to the log file in binary format.")
  parser.add_argument('output_filepath', help="Path to write the text output to.")

  return parser.parse_args()

def readcheck(binfile, numbytes, exit=False):
  b = binfile.read(numbytes)
  if len(b) < numbytes:
    if exit:
      print("Log data corrupted.")
      sys.exit(-1)
    else:
      return b''
  return b

def v1_conversion(binfile, txtfile):
  b = readcheck(binfile, 4, True)
  signature = struct.unpack('<I', b)[0]
  if signature == ENDIANNESS_BYTES:
    endianness = '<'
  else:
    signature = struct.unpack('>I', b)[0]
    if signature == ENDIANNESS_BYTES:
      endianness = '>'
    else:
      print("Invalid log file endianness. Exiting.")
      sys.exit(-1)
  
  b = readcheck(binfile, 4, True)
  int_size = struct.unpack(f'{endianness}I', b)[0]
  int_format = 'I' if int_size == 4 else 'Q'

  b = readcheck(binfile, 4, True)
  float_size = struct.unpack(f'{endianness}I', b)[0]
  float_format = 'f' if float_size == 4 else 'd'

  print(TEXT_LOG_PREAMBLE + '1', file=txtfile)
  print(TEXT_LOG_HEADER, file=txtfile)
  while True:
    b = binfile.read(4)
    if len(b) < 4: break
    unixtime = struct.unpack(f'{endianness}I', b)[0]
    b = binfile.read(4)
    if len(b) < 4:
      print("Log data corrupted.")
      sys.exit(-1)
    temp = struct.unpack(f'{endianness}{float_format}', b)[0]
    #b = binfile.read(4)
    #if len(b) < 4:
    #  print("Log data corrupted.")
    #  sys.exit(-1)
    #hum = struct.unpack(f'{endianness}{float_format}', b)[0]

    timestr = time.strftime("%Y-%m-%d,%H:%M:%S", time.gmtime(unixtime))

    print(f"{timestr},{temp}", file=txtfile)

conversion_table = {
  1 : v1_conversion
}

if __name__ == "__main__":
  cli_args = get_cli_args()

  with open(cli_args.binary_logfile, 'rb') as binfile, open(cli_args.output_filepath, 'w') as txtfile:
    header = ''
    while True:
      b = binfile.read(1)
      if b == b'\x00' or b == b'': break
      header += b.decode()
      if b == PREAMBLE_END_TOKEN: break
    if header.startswith(LOG_PREAMBLE):
      version = int(header[len(LOG_PREAMBLE):])
      conversion_table[version](binfile, txtfile)
    else:
      print("Invalid or unknown log preamble. Exiting.")
      sys.exit(-1)