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"""This module allows to connect to a MySQL database."""
import json
from typing import TYPE_CHECKING, Dict, Optional, Tuple, Union
from airflow.hooks.dbapi import DbApiHook
from airflow.models import Connection
if TYPE_CHECKING:
from mysql.connector.abstracts import MySQLConnectionAbstract
from MySQLdb.connections import Connection as MySQLdbConnection
[docs]MySQLConnectionTypes = Union['MySQLdbConnection', 'MySQLConnectionAbstract']
[docs]class MySqlHook(DbApiHook):
"""
Interact with MySQL.
You can specify charset in the extra field of your connection
as ``{"charset": "utf8"}``. Also you can choose cursor as
``{"cursor": "SSCursor"}``. Refer to the MySQLdb.cursors for more details.
Note: For AWS IAM authentication, use iam in the extra connection parameters
and set it to true. Leave the password field empty. This will use the
"aws_default" connection to get the temporary token unless you override
in extras.
extras example: ``{"iam":true, "aws_conn_id":"my_aws_conn"}``
:param schema: The MySQL database schema to connect to.
:param connection: The :ref:`MySQL connection id <howto/connection:mysql>` used for MySQL credentials.
"""
[docs] conn_name_attr = 'mysql_conn_id'
[docs] default_conn_name = 'mysql_default'
[docs] supports_autocommit = True
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
self.schema = kwargs.pop("schema", None)
self.connection = kwargs.pop("connection", None)
[docs] def set_autocommit(self, conn: MySQLConnectionTypes, autocommit: bool) -> None:
"""
The MySQLdb (mysqlclient) client uses an `autocommit` method rather
than an `autocommit` property to set the autocommit setting
:param conn: connection to set autocommit setting
:param autocommit: autocommit setting
:rtype: None
"""
if hasattr(conn.__class__, 'autocommit') and isinstance(conn.__class__.autocommit, property):
conn.autocommit = autocommit
else:
conn.autocommit(autocommit)
[docs] def get_autocommit(self, conn: MySQLConnectionTypes) -> bool:
"""
The MySQLdb (mysqlclient) client uses a `get_autocommit` method
rather than an `autocommit` property to get the autocommit setting
:param conn: connection to get autocommit setting from.
:return: connection autocommit setting
:rtype: bool
"""
if hasattr(conn.__class__, 'autocommit') and isinstance(conn.__class__.autocommit, property):
return conn.autocommit
else:
return conn.get_autocommit()
def _get_conn_config_mysql_client(self, conn: Connection) -> Dict:
conn_config = {
"user": conn.login,
"passwd": conn.password or '',
"host": conn.host or 'localhost',
"db": self.schema or conn.schema or '',
}
# check for authentication via AWS IAM
if conn.extra_dejson.get('iam', False):
conn_config['passwd'], conn.port = self.get_iam_token(conn)
conn_config["read_default_group"] = 'enable-cleartext-plugin'
conn_config["port"] = int(conn.port) if conn.port else 3306
if conn.extra_dejson.get('charset', False):
conn_config["charset"] = conn.extra_dejson["charset"]
if conn_config["charset"].lower() in ('utf8', 'utf-8'):
conn_config["use_unicode"] = True
if conn.extra_dejson.get('cursor', False):
import MySQLdb.cursors
if (conn.extra_dejson["cursor"]).lower() == 'sscursor':
conn_config["cursorclass"] = MySQLdb.cursors.SSCursor
elif (conn.extra_dejson["cursor"]).lower() == 'dictcursor':
conn_config["cursorclass"] = MySQLdb.cursors.DictCursor
elif (conn.extra_dejson["cursor"]).lower() == 'ssdictcursor':
conn_config["cursorclass"] = MySQLdb.cursors.SSDictCursor
local_infile = conn.extra_dejson.get('local_infile', False)
if conn.extra_dejson.get('ssl', False):
# SSL parameter for MySQL has to be a dictionary and in case
# of extra/dejson we can get string if extra is passed via
# URL parameters
dejson_ssl = conn.extra_dejson['ssl']
if isinstance(dejson_ssl, str):
dejson_ssl = json.loads(dejson_ssl)
conn_config['ssl'] = dejson_ssl
if conn.extra_dejson.get('unix_socket'):
conn_config['unix_socket'] = conn.extra_dejson['unix_socket']
if local_infile:
conn_config["local_infile"] = 1
return conn_config
def _get_conn_config_mysql_connector_python(self, conn: Connection) -> Dict:
conn_config = {
'user': conn.login,
'password': conn.password or '',
'host': conn.host or 'localhost',
'database': self.schema or conn.schema or '',
'port': int(conn.port) if conn.port else 3306,
}
if conn.extra_dejson.get('allow_local_infile', False):
conn_config["allow_local_infile"] = True
return conn_config
[docs] def get_conn(self) -> MySQLConnectionTypes:
"""
Establishes a connection to a mysql database
by extracting the connection configuration from the Airflow connection.
.. note:: By default it connects to the database via the mysqlclient library.
But you can also choose the mysql-connector-python library which lets you connect through ssl
without any further ssl parameters required.
:return: a mysql connection object
"""
conn = self.connection or self.get_connection(getattr(self, self.conn_name_attr))
client_name = conn.extra_dejson.get('client', 'mysqlclient')
if client_name == 'mysqlclient':
import MySQLdb
conn_config = self._get_conn_config_mysql_client(conn)
return MySQLdb.connect(**conn_config)
if client_name == 'mysql-connector-python':
import mysql.connector
conn_config = self._get_conn_config_mysql_connector_python(conn)
return mysql.connector.connect(**conn_config)
raise ValueError('Unknown MySQL client name provided!')
[docs] def bulk_load(self, table: str, tmp_file: str) -> None:
"""Loads a tab-delimited file into a database table"""
conn = self.get_conn()
cur = conn.cursor()
cur.execute(
f"""
LOAD DATA LOCAL INFILE '{tmp_file}'
INTO TABLE {table}
"""
)
conn.commit()
[docs] def bulk_dump(self, table: str, tmp_file: str) -> None:
"""Dumps a database table into a tab-delimited file"""
conn = self.get_conn()
cur = conn.cursor()
cur.execute(
f"""
SELECT * INTO OUTFILE '{tmp_file}'
FROM {table}
"""
)
conn.commit()
@staticmethod
def _serialize_cell(cell: object, conn: Optional[Connection] = None) -> object:
"""
The package MySQLdb converts an argument to a literal
when passing those separately to execute. Hence, this method does nothing.
:param cell: The cell to insert into the table
:param conn: The database connection
:return: The same cell
:rtype: object
"""
return cell
[docs] def get_iam_token(self, conn: Connection) -> Tuple[str, int]:
"""
Uses AWSHook to retrieve a temporary password to connect to MySQL
Port is required. If none is provided, default 3306 is used
"""
from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook
aws_conn_id = conn.extra_dejson.get('aws_conn_id', 'aws_default')
aws_hook = AwsBaseHook(aws_conn_id, client_type='rds')
if conn.port is None:
port = 3306
else:
port = conn.port
client = aws_hook.get_conn()
token = client.generate_db_auth_token(conn.host, port, conn.login)
return token, port
[docs] def bulk_load_custom(
self, table: str, tmp_file: str, duplicate_key_handling: str = 'IGNORE', extra_options: str = ''
) -> None:
"""
A more configurable way to load local data from a file into the database.
.. warning:: According to the mysql docs using this function is a
`security risk <https://dev.mysql.com/doc/refman/8.0/en/load-data-local.html>`_.
If you want to use it anyway you can do so by setting a client-side + server-side option.
This depends on the mysql client library used.
:param table: The table were the file will be loaded into.
:param tmp_file: The file (name) that contains the data.
:param duplicate_key_handling: Specify what should happen to duplicate data.
You can choose either `IGNORE` or `REPLACE`.
.. seealso::
https://dev.mysql.com/doc/refman/8.0/en/load-data.html#load-data-duplicate-key-handling
:param extra_options: More sql options to specify exactly how to load the data.
.. seealso:: https://dev.mysql.com/doc/refman/8.0/en/load-data.html
"""
conn = self.get_conn()
cursor = conn.cursor()
cursor.execute(
f"""
LOAD DATA LOCAL INFILE '{tmp_file}'
{duplicate_key_handling}
INTO TABLE {table}
{extra_options}
"""
)
cursor.close()
conn.commit()