#
# Licensed to the Apache Software Foundation (ASF) under one
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# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
from collections.abc import Sequence
from functools import cached_property
from typing import TYPE_CHECKING, Any
from airflow.exceptions import AirflowException
from airflow.providers.common.sql.hooks.sql import DbApiHook
from airflow.providers.common.sql.triggers.sql import SQLExecuteQueryTrigger
from airflow.providers.common.sql.version_compat import BaseHook, BaseOperator
if TYPE_CHECKING:
import jinja2
try:
from airflow.sdk.definitions.context import Context
except ImportError:
# TODO: Remove once provider drops support for Airflow 2
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. (templated)
:param source_hook_params: source hook parameters.
:param destination_conn_id: destination connection. (templated)
:param destination_hook_params: destination hook parameters.
: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.
:param page_size: number of records to be read in paginated mode (optional).
:param paginated_sql_statement_clause: SQL statement clause to be used for pagination (optional).
"""
[docs]
template_fields: Sequence[str] = (
"source_conn_id",
"destination_conn_id",
"sql",
"destination_table",
"preoperator",
"insert_args",
"page_size",
"paginated_sql_statement_clause",
)
[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,
source_hook_params: dict | None = None,
destination_conn_id: str,
destination_hook_params: dict | None = None,
preoperator: str | list[str] | None = None,
insert_args: dict | None = None,
page_size: int | None = None,
paginated_sql_statement_clause: str | None = None,
**kwargs,
) -> None:
super().__init__(**kwargs)
[docs]
self.destination_table = destination_table
[docs]
self.source_conn_id = source_conn_id
[docs]
self.source_hook_params = source_hook_params
[docs]
self.destination_conn_id = destination_conn_id
[docs]
self.destination_hook_params = destination_hook_params
[docs]
self.preoperator = preoperator
[docs]
self.insert_args = insert_args or {}
[docs]
self.page_size = page_size
[docs]
self.paginated_sql_statement_clause = paginated_sql_statement_clause or "{} LIMIT {} OFFSET {}"
@classmethod
[docs]
def get_hook(cls, conn_id: str, hook_params: dict | None = None) -> DbApiHook:
"""
Return DbApiHook for this connection id.
:param conn_id: connection id
:param hook_params: hook parameters
:return: DbApiHook for this connection
"""
connection = BaseHook.get_connection(conn_id)
hook = connection.get_hook(hook_params=hook_params)
if not isinstance(hook, DbApiHook):
raise RuntimeError(f"Hook for connection {conn_id!r} must be of type {DbApiHook.__name__}")
return hook
@cached_property
[docs]
def source_hook(self) -> DbApiHook:
return self.get_hook(conn_id=self.source_conn_id, hook_params=self.source_hook_params)
@cached_property
[docs]
def destination_hook(self) -> DbApiHook:
return self.get_hook(conn_id=self.destination_conn_id, hook_params=self.destination_hook_params)
[docs]
def get_paginated_sql(self, offset: int) -> str:
"""Format the paginated SQL statement using the current format."""
return self.paginated_sql_statement_clause.format(self.sql, self.page_size, offset)
[docs]
def render_template_fields(
self,
context: Context,
jinja_env: jinja2.Environment | None = None,
) -> None:
super().render_template_fields(context=context, jinja_env=jinja_env)
# Make sure string are converted to integers
if isinstance(self.page_size, str):
self.page_size = int(self.page_size)
commit_every = self.insert_args.get("commit_every")
if isinstance(commit_every, str):
self.insert_args["commit_every"] = int(commit_every)
[docs]
def execute(self, context: Context):
if self.preoperator:
self.log.info("Running preoperator")
self.log.info(self.preoperator)
self.destination_hook.run(self.preoperator)
if self.page_size and isinstance(self.sql, str):
self.defer(
trigger=SQLExecuteQueryTrigger(
conn_id=self.source_conn_id,
hook_params=self.source_hook_params,
sql=self.get_paginated_sql(0),
),
method_name=self.execute_complete.__name__,
)
else:
self.log.info("Extracting data from %s", self.source_conn_id)
self.log.info("Executing: \n %s", self.sql)
results = self.source_hook.get_records(self.sql)
self.log.info("Inserting rows into %s", self.destination_conn_id)
self.destination_hook.insert_rows(table=self.destination_table, rows=results, **self.insert_args)
[docs]
def execute_complete(
self,
context: Context,
event: dict[Any, Any] | None = None,
) -> Any:
if event:
if event.get("status") == "failure":
raise AirflowException(event.get("message"))
results = event.get("results")
if results:
map_index = context["ti"].map_index
offset = (
context["ti"].xcom_pull(
key="offset",
task_ids=self.task_id,
dag_id=self.dag_id,
map_indexes=map_index,
default=0,
)
+ self.page_size
)
self.log.info("Offset increased to %d", offset)
context["ti"].xcom_push(key="offset", value=offset)
self.log.info("Inserting %d rows into %s", len(results), self.destination_conn_id)
self.destination_hook.insert_rows(
table=self.destination_table, rows=results, **self.insert_args
)
self.log.info(
"Inserting %d rows into %s done!",
len(results),
self.destination_conn_id,
)
self.defer(
trigger=SQLExecuteQueryTrigger(
conn_id=self.source_conn_id,
hook_params=self.source_hook_params,
sql=self.get_paginated_sql(offset),
),
method_name=self.execute_complete.__name__,
)
else:
self.log.info(
"No more rows to fetch into %s; ending transfer.",
self.destination_table,
)