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from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults
from airflow.hooks.base_hook import BaseHook
[docs]class GenericTransfer(BaseOperator):
"""
Moves data from a connection to another, assuming that they both
provide the required methods in their respective hooks. The source hook
needs to expose a `get_records` method, and the destination a
`insert_rows` method.
This is meant to be used on small-ish datasets that fit in memory.
:param sql: SQL query to execute against the source database. (templated)
:type sql: str
:param destination_table: target table. (templated)
:type destination_table: str
:param source_conn_id: source connection
:type source_conn_id: str
:param destination_conn_id: source connection
:type destination_conn_id: str
:param preoperator: sql statement or list of statements to be
executed prior to loading the data. (templated)
:type preoperator: str or list[str]
"""
[docs] template_fields = ('sql', 'destination_table', 'preoperator')
[docs] template_ext = ('.sql', '.hql',)
@apply_defaults
def __init__(
self,
sql,
destination_table,
source_conn_id,
destination_conn_id,
preoperator=None,
*args, **kwargs):
super(GenericTransfer, self).__init__(*args, **kwargs)
self.sql = sql
self.destination_table = destination_table
self.source_conn_id = source_conn_id
self.destination_conn_id = destination_conn_id
self.preoperator = preoperator
[docs] def execute(self, context):
source_hook = BaseHook.get_hook(self.source_conn_id)
self.log.info("Extracting data from %s", self.source_conn_id)
self.log.info("Executing: \n %s", self.sql)
results = source_hook.get_records(self.sql)
destination_hook = BaseHook.get_hook(self.destination_conn_id)
if self.preoperator:
self.log.info("Running preoperator")
self.log.info(self.preoperator)
destination_hook.run(self.preoperator)
self.log.info("Inserting rows into %s", self.destination_conn_id)
destination_hook.insert_rows(table=self.destination_table, rows=results)