Source code for airflow.operators.generic_transfer
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from typing import List, Optional, Sequence, Union
from airflow.hooks.base import BaseHook
from airflow.models import BaseOperator
from airflow.utils.context import Context
[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)
:param destination_table: target table. (templated)
:param source_conn_id: source connection
:param destination_conn_id: destination connection
:param preoperator: sql statement or list of statements to be
executed prior to loading the data. (templated)
:param insert_args: extra params for `insert_rows` method.
"""
[docs] template_fields: Sequence[str] = ('sql', 'destination_table', 'preoperator')
[docs] template_ext: Sequence[str] = (
'.sql',
'.hql',
)
[docs] template_fields_renderers = {"preoperator": "sql"}
def __init__(
self,
*,
sql: str,
destination_table: str,
source_conn_id: str,
destination_conn_id: str,
preoperator: Optional[Union[str, List[str]]] = None,
insert_args: Optional[dict] = None,
**kwargs,
) -> None:
super().__init__(**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
self.insert_args = insert_args or {}
[docs] def execute(self, context: Context):
source_hook = BaseHook.get_hook(self.source_conn_id)
destination_hook = BaseHook.get_hook(self.destination_conn_id)
self.log.info("Extracting data from %s", self.source_conn_id)
self.log.info("Executing: \n %s", self.sql)
get_records = getattr(source_hook, 'get_records', None)
if not callable(get_records):
raise RuntimeError(
f"Hook for connection {self.source_conn_id!r} "
f"({type(source_hook).__name__}) has no `get_records` method"
)
else:
results = get_records(self.sql)
if self.preoperator:
run = getattr(destination_hook, 'run', None)
if not callable(run):
raise RuntimeError(
f"Hook for connection {self.destination_conn_id!r} "
f"({type(destination_hook).__name__}) has no `run` method"
)
self.log.info("Running preoperator")
self.log.info(self.preoperator)
run(self.preoperator)
insert_rows = getattr(destination_hook, 'insert_rows', None)
if not callable(insert_rows):
raise RuntimeError(
f"Hook for connection {self.destination_conn_id!r} "
f"({type(destination_hook).__name__}) has no `insert_rows` method"
)
self.log.info("Inserting rows into %s", self.destination_conn_id)
insert_rows(table=self.destination_table, rows=results, **self.insert_args)
