common_tools.py

from config import *
import hashlib
import sys


def getHash(file, block_count=0):
  """
  Returns a sha256 hash for the specified file.
  Eventually sent to server to check for restarts.
  """
  hash = hashlib.sha256()
  i = 0
  with open(file, "r") as file:
    while True:
      data = file.read(CHUNK_SIZE)
      if not data or (block_count != 0 and i >= block_count):
        file.close()
        return hash.hexdigest()
      i += 1
      hash.update(data)

def fail(msg):
  """
  Simple fail function that prints and logs the error message and then exits.
  """
  logger.error(msg)
  sys.stderr.write(msg)
  sys.exit(1)


# from: http://stackoverflow.com/questions/2281850/timeout-function-if-it-takes-too-long-to-finish
from functools import wraps
import errno
import os
import signal

class TimeoutError(Exception):
    pass

def timeout(seconds=10, error_message=os.strerror(errno.ETIME)):
    def decorator(func):
        def _handle_timeout(signum, frame):
            raise TimeoutError(error_message)

        def wrapper(*args, **kwargs):
            signal.signal(signal.SIGALRM, _handle_timeout)
            signal.alarm(seconds)
            try:
                result = func(*args, **kwargs)
            finally:
                signal.alarm(0)
            return result

        return wraps(func)(wrapper)

    return decorator