import requests


class OpenWeatherMapError(RuntimeError):
    pass


def openweathermap_json(apikey, cityid):
    """Returns parsed JSON as returned by openweathermap for the given cityid.
    In case of errors, an OpenWeatherMapError is raised."""
    baseurl = 'http://api.openweathermap.org/data/2.5/weather'
    query = baseurl + '?units=metric&APPID={}&id={}&lang=de'.format(apikey, cityid)
    try:
        response = requests.get(query)
        if response.status_code != 200:
            raise OpenWeatherMapError('Got status code {} ({}).'.format(response.status_code, response.reason))
        else:
            return response.json()
    except requests.exceptions.RequestException as error:
        raise OpenWeatherMapError('Request not successful: {}'.format(error))