Source code for cloudant_hook

# -*- coding: utf-8 -*-
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from past.builtins import unicode

import cloudant
import logging

from airflow.exceptions import AirflowException
from airflow.hooks.base_hook import BaseHook


class CloudantHook(BaseHook):
    """Interact with Cloudant.

    This class is a thin wrapper around the cloudant python library. See the
    documentation `here <https://github.com/cloudant-labs/cloudant-python>`_.
    """
    def __init__(self, cloudant_conn_id='cloudant_default'):
        super(CloudantHook, self).__init__('cloudant')
        self.cloudant_conn_id = cloudant_conn_id

    def get_conn(self):
        def _str(s):
            # cloudant-python doesn't support unicode.
            if isinstance(s, unicode):
                logging.debug(('cloudant-python does not support unicode. '
                               'Encoding %s as ascii using "ignore".'),
                              s)
                return s.encode('ascii', 'ignore')

            return s

        conn = self.get_connection(self.cloudant_conn_id)

        for conn_param in ['host', 'password', 'schema']:
            if not hasattr(conn, conn_param) or not getattr(conn, conn_param):
                raise AirflowException(
                    'missing connection parameter {0}'.format(conn_param)
                )

        # In the connection form:
        # - 'host' is renamed to 'Account'
        # - 'login' is renamed 'Username (or API Key)'
        # - 'schema' is renamed to 'Database'
        #
        # So, use the 'host' attribute as the account name, and, if login is
        # defined, use that as the username.
        account = cloudant.Account(_str(conn.host))

        username = _str(conn.login or conn.host)

        account.login(
            username,
            _str(conn.password)).raise_for_status()

        return account.database(_str(conn.schema))

    def db(self):
        """Returns the Database object for this hook.

        See the documentation for cloudant-python here
        https://github.com/cloudant-labs/cloudant-python.
        """
        return self.get_conn()