Handle generator exceptions in its consumer

Question

This is a follow-up to Handle an exception thrown in a generator and discusses a more general problem.

I have a function that reads data in different formats. All fo

Answer 1

You can return a tuple of record and exception in the parsefunc and let the consumer function decide what to do with the exception:

import random

def get_record(line):
  num = random.randint(0, 3)
  if num == 3:
    raise Exception("3 means danger")
  return line


def parsefunc(stream):
  for line in stream:
    try:
      rec = get_record(line)
    except Exception as e:
      yield (None, e)
    else:
      yield (rec, None)

if __name__ == '__main__':
  with open('temp.txt') as f:
    for rec, e in parsefunc(f):
      if e:
        print "Got an exception %s" % e
      else:
        print "Got a record %s" % rec