DateTime ParamType for the click CLI Parser library (uses arrow)

click_date_type.py

import arrow
from arrow.parser import ParserError
import click


class DateParamType(click.ParamType):
    name = 'date'

    def __init__(self, date_format="YYYY-MM-DD"):
        super(DateParamType, self).__init__()
        self.date_format = date_format

    def convert(self, value, param, ctx):
        try:
            return arrow.get(value, self.date_format).date()
        except ParserError:
            self.fail("Could not parse '%s' as a date." % (value, ))