import time


def make_day_julian(isodate):
    """Generate a Julian date integer from a YYYY-MM-DD string.

    Args:
        isodate (str): ISO 8601 date string, e.g. "2018-03-17" (Mar 17, 2018)
    Returns:
        (int): Julian date
    """
    dt = time.strptime(isodate, "%Y-%m-%d")
    return int(time.strftime("%j", dt))