#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# 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.
"""This module contains operator to move data from MySQL to Druid."""
from collections import OrderedDict
from tempfile import NamedTemporaryFile
from typing import Dict, Optional
import MySQLdb
import unicodecsv as csv
from airflow.models import BaseOperator
from airflow.providers.apache.hive.hooks.hive import HiveCliHook
from airflow.providers.mysql.hooks.mysql import MySqlHook
from airflow.utils.decorators import apply_defaults
[docs]class MySqlToHiveOperator(BaseOperator):
"""
Moves data from MySql to Hive. The operator runs your query against
MySQL, stores the file locally before loading it into a Hive table.
If the ``create`` or ``recreate`` arguments are set to ``True``,
a ``CREATE TABLE`` and ``DROP TABLE`` statements are generated.
Hive data types are inferred from the cursor's metadata. Note that the
table generated in Hive uses ``STORED AS textfile``
which isn't the most efficient serialization format. If a
large amount of data is loaded and/or if the table gets
queried considerably, you may want to use this operator only to
stage the data into a temporary table before loading it into its
final destination using a ``HiveOperator``.
:param sql: SQL query to execute against the MySQL database. (templated)
:type sql: str
:param hive_table: target Hive table, use dot notation to target a
specific database. (templated)
:type hive_table: str
:param create: whether to create the table if it doesn't exist
:type create: bool
:param recreate: whether to drop and recreate the table at every
execution
:type recreate: bool
:param partition: target partition as a dict of partition columns
and values. (templated)
:type partition: dict
:param delimiter: field delimiter in the file
:type delimiter: str
:param quoting: controls when quotes should be generated by csv writer,
It can take on any of the csv.QUOTE_* constants.
:type quoting: str
:param quotechar: one-character string used to quote fields
containing special characters.
:type quotechar: str
:param escapechar: one-character string used by csv writer to escape
the delimiter or quotechar.
:type escapechar: str
:param mysql_conn_id: source mysql connection
:type mysql_conn_id: str
:param hive_conn_id: destination hive connection
:type hive_conn_id: str
:param tblproperties: TBLPROPERTIES of the hive table being created
:type tblproperties: dict
"""
[docs] template_fields = ('sql', 'partition', 'hive_table')
[docs] template_ext = ('.sql',)
@apply_defaults
def __init__( # pylint: disable=too-many-arguments
self,
*,
sql: str,
hive_table: str,
create: bool = True,
recreate: bool = False,
partition: Optional[Dict] = None,
delimiter: str = chr(1),
quoting: Optional[str] = None,
quotechar: str = '"',
escapechar: Optional[str] = None,
mysql_conn_id: str = 'mysql_default',
hive_cli_conn_id: str = 'hive_cli_default',
tblproperties: Optional[Dict] = None,
**kwargs,
) -> None:
super().__init__(**kwargs)
self.sql = sql
self.hive_table = hive_table
self.partition = partition
self.create = create
self.recreate = recreate
self.delimiter = str(delimiter)
self.quoting = quoting or csv.QUOTE_MINIMAL
self.quotechar = quotechar
self.escapechar = escapechar
self.mysql_conn_id = mysql_conn_id
self.hive_cli_conn_id = hive_cli_conn_id
self.partition = partition or {}
self.tblproperties = tblproperties
@classmethod
[docs] def type_map(cls, mysql_type: int) -> str:
"""Maps MySQL type to Hive type."""
types = MySQLdb.constants.FIELD_TYPE
type_map = {
types.BIT: 'INT',
types.DECIMAL: 'DOUBLE',
types.NEWDECIMAL: 'DOUBLE',
types.DOUBLE: 'DOUBLE',
types.FLOAT: 'DOUBLE',
types.INT24: 'INT',
types.LONG: 'BIGINT',
types.LONGLONG: 'DECIMAL(38,0)',
types.SHORT: 'INT',
types.TINY: 'SMALLINT',
types.YEAR: 'INT',
types.TIMESTAMP: 'TIMESTAMP',
}
return type_map.get(mysql_type, 'STRING')
[docs] def execute(self, context: Dict[str, str]):
hive = HiveCliHook(hive_cli_conn_id=self.hive_cli_conn_id)
mysql = MySqlHook(mysql_conn_id=self.mysql_conn_id)
self.log.info("Dumping MySQL query results to local file")
conn = mysql.get_conn()
cursor = conn.cursor()
cursor.execute(self.sql)
with NamedTemporaryFile("wb") as f:
csv_writer = csv.writer(
f,
delimiter=self.delimiter,
quoting=self.quoting,
quotechar=self.quotechar,
escapechar=self.escapechar,
encoding="utf-8",
)
field_dict = OrderedDict()
for field in cursor.description:
field_dict[field[0]] = self.type_map(field[1])
csv_writer.writerows(cursor)
f.flush()
cursor.close()
conn.close()
self.log.info("Loading file into Hive")
hive.load_file(
f.name,
self.hive_table,
field_dict=field_dict,
create=self.create,
partition=self.partition,
delimiter=self.delimiter,
recreate=self.recreate,
tblproperties=self.tblproperties,
)
