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"""
This module contains sensor that check the existence
of a table in a Cassandra cluster.
"""

from typing import Any, Dict

from airflow.providers.apache.cassandra.hooks.cassandra import CassandraHook
from airflow.sensors.base import BaseSensorOperator


class CassandraTableSensor(BaseSensorOperator):
    """
    Checks for the existence of a table in a Cassandra cluster.

    .. seealso::
        For more information on how to use this operator, take a look at the guide:
        :ref:`howto/operator:CassandraTableSensor`


    For example, if you want to wait for a table called 't' to be created
    in a keyspace 'k', instantiate it as follows:

    >>> cassandra_sensor = CassandraTableSensor(table="k.t",
    ...                                         cassandra_conn_id="cassandra_default",
    ...                                         task_id="cassandra_sensor")

    :param table: Target Cassandra table.
        Use dot notation to target a specific keyspace.
    :type table: str
    :param cassandra_conn_id: The connection ID to use
        when connecting to Cassandra cluster
    :type cassandra_conn_id: str
    """

    template_fields = ('table',)

    def __init__(self, *, table: str, cassandra_conn_id: str, **kwargs: Any) -> None:
        super().__init__(**kwargs)
        self.cassandra_conn_id = cassandra_conn_id
        self.table = table

    def poke(self, context: Dict[Any, Any]) -> bool:
        self.log.info('Sensor check existence of table: %s', self.table)
        hook = CassandraHook(self.cassandra_conn_id)
        return hook.table_exists(self.table)
