Source code for airflow.contrib.sensors.cassandra_table_sensor

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from airflow.contrib.hooks.cassandra_hook import CassandraHook
from airflow.sensors.base_sensor_operator import BaseSensorOperator
from airflow.utils.decorators import apply_defaults


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

    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")
    """
[docs]    template_fields = ('table',)

    @apply_defaults
    def __init__(self, table, cassandra_conn_id, *args, **kwargs):
        """
        Create a new CassandraTableSensor

        :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
        """
        super(CassandraTableSensor, self).__init__(*args, **kwargs)
        self.cassandra_conn_id = cassandra_conn_id
        self.table = table

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