Source code for airflow.providers.amazon.aws.hooks.redshift_sql
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import sys
from typing import Dict, List, Optional, Union
import redshift_connector
from redshift_connector import Connection as RedshiftConnection
from sqlalchemy import create_engine
from sqlalchemy.engine.url import URL
from airflow.hooks.dbapi import DbApiHook
if sys.version_info >= (3, 8):
from functools import cached_property
else:
from cached_property import cached_property
[docs]class RedshiftSQLHook(DbApiHook):
"""
Execute statements against Amazon Redshift, using redshift_connector
This hook requires the redshift_conn_id connection.
:param redshift_conn_id: reference to
:ref:`Amazon Redshift connection id<howto/connection:redshift>`
.. note::
get_sqlalchemy_engine() and get_uri() depend on sqlalchemy-amazon-redshift
"""
[docs] conn_name_attr = 'redshift_conn_id'
[docs] default_conn_name = 'redshift_default'
[docs] hook_name = 'Amazon Redshift'
[docs] supports_autocommit = True
@staticmethod
[docs] def get_ui_field_behavior() -> Dict:
"""Returns custom field behavior"""
return {
"hidden_fields": [],
"relabeling": {'login': 'User', 'schema': 'Database'},
}
@cached_property
[docs] def conn(self):
return self.get_connection(self.redshift_conn_id) # type: ignore[attr-defined]
def _get_conn_params(self) -> Dict[str, Union[str, int]]:
"""Helper method to retrieve connection args"""
conn = self.conn
conn_params: Dict[str, Union[str, int]] = {}
if conn.login:
conn_params['user'] = conn.login
if conn.password:
conn_params['password'] = conn.password
if conn.host:
conn_params['host'] = conn.host
if conn.port:
conn_params['port'] = conn.port
if conn.schema:
conn_params['database'] = conn.schema
return conn_params
[docs] def get_uri(self) -> str:
"""Overrides DbApiHook get_uri to use redshift_connector sqlalchemy dialect as driver name"""
conn_params = self._get_conn_params()
if 'user' in conn_params:
conn_params['username'] = conn_params.pop('user')
return str(URL(drivername='redshift+redshift_connector', **conn_params))
[docs] def get_sqlalchemy_engine(self, engine_kwargs=None):
"""Overrides DbApiHook get_sqlalchemy_engine to pass redshift_connector specific kwargs"""
conn_kwargs = self.conn.extra_dejson
if engine_kwargs is None:
engine_kwargs = {}
if "connect_args" in engine_kwargs:
engine_kwargs["connect_args"] = {**conn_kwargs, **engine_kwargs["connect_args"]}
else:
engine_kwargs["connect_args"] = conn_kwargs
return create_engine(self.get_uri(), **engine_kwargs)
[docs] def get_table_primary_key(self, table: str, schema: Optional[str] = "public") -> Optional[List[str]]:
"""
Helper method that returns the table primary key
:param table: Name of the target table
:param table: Name of the target schema, public by default
:return: Primary key columns list
:rtype: List[str]
"""
sql = """
select kcu.column_name
from information_schema.table_constraints tco
join information_schema.key_column_usage kcu
on kcu.constraint_name = tco.constraint_name
and kcu.constraint_schema = tco.constraint_schema
and kcu.constraint_name = tco.constraint_name
where tco.constraint_type = 'PRIMARY KEY'
and kcu.table_schema = %s
and kcu.table_name = %s
"""
pk_columns = [row[0] for row in self.get_records(sql, (schema, table))]
return pk_columns or None
[docs] def get_conn(self) -> RedshiftConnection:
"""Returns a redshift_connector.Connection object"""
conn_params = self._get_conn_params()
conn_kwargs_dejson = self.conn.extra_dejson
conn_kwargs: Dict = {**conn_params, **conn_kwargs_dejson}
conn: RedshiftConnection = redshift_connector.connect(**conn_kwargs)
return conn
