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import tempfile
from airflow.hooks.hive_hooks import HiveServer2Hook
from airflow.hooks.samba_hook import SambaHook
from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults
from airflow.utils.operator_helpers import context_to_airflow_vars
[docs]class Hive2SambaOperator(BaseOperator):
"""
Executes hql code in a specific Hive database and loads the
results of the query as a csv to a Samba location.
:param hql: the hql to be exported. (templated)
:type hql: str
:param hiveserver2_conn_id: reference to the hiveserver2 service
:type hiveserver2_conn_id: str
:param samba_conn_id: reference to the samba destination
:type samba_conn_id: str
"""
[docs] template_fields = ('hql', 'destination_filepath')
[docs] template_ext = ('.hql', '.sql',)
@apply_defaults
def __init__(
self, hql,
destination_filepath,
samba_conn_id='samba_default',
hiveserver2_conn_id='hiveserver2_default',
*args, **kwargs):
super(Hive2SambaOperator, self).__init__(*args, **kwargs)
self.hiveserver2_conn_id = hiveserver2_conn_id
self.samba_conn_id = samba_conn_id
self.destination_filepath = destination_filepath
self.hql = hql.strip().rstrip(';')
[docs] def execute(self, context):
samba = SambaHook(samba_conn_id=self.samba_conn_id)
hive = HiveServer2Hook(hiveserver2_conn_id=self.hiveserver2_conn_id)
tmpfile = tempfile.NamedTemporaryFile()
self.log.info("Fetching file from Hive")
hive.to_csv(hql=self.hql, csv_filepath=tmpfile.name,
hive_conf=context_to_airflow_vars(context))
self.log.info("Pushing to samba")
samba.push_from_local(self.destination_filepath, tmpfile.name)