gistfile1.py

import csv
from contextlib import contextmanager
import sys


@contextmanager
def getstdin():
    try:
        yield sys.stdin  # process.stdout
        print "a"
    except Exception as e:
        print "b", e
    except GeneratorExit as e:
        # generator exit is considered regular.
        # it happens for with the timeout exception.
        print "c"
    finally:
        print "d"


print "START"
with getstdin() as in_stream:
    for row in csv.reader(in_stream, delimiter=","):
        print row
print "DONE"