Source code for airflow.providers.amazon.aws.hooks.redshift_sql
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from __future__ import annotations
from functools import cached_property
from typing import TYPE_CHECKING
import redshift_connector
from redshift_connector import Connection as RedshiftConnection
from sqlalchemy import create_engine
from sqlalchemy.engine.url import URL
from airflow.exceptions import AirflowException
from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook
from airflow.providers.common.sql.hooks.sql import DbApiHook
if TYPE_CHECKING:
from airflow.models.connection import Connection
[docs]class RedshiftSQLHook(DbApiHook):
"""Execute statements against Amazon Redshift.
This hook requires the redshift_conn_id connection.
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
with aws_conn_id when initializing the hook.
The cluster-identifier is extracted from the beginning of
the host field, so is optional. It can however be overridden in the extra field.
extras example: ``{"iam":true}``
: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
def __init__(self, *args, aws_conn_id: str = "aws_default", **kwargs) -> None:
super().__init__(*args, **kwargs)
self.aws_conn_id = aws_conn_id
@staticmethod
[docs] def get_ui_field_behaviour() -> dict:
"""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, str | int]:
"""Retrieve connection parameters."""
conn = self.conn
conn_params: dict[str, str | int] = {}
if conn.extra_dejson.get("iam", False):
conn.login, conn.password, conn.port = self.get_iam_token(conn)
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_iam_token(self, conn: Connection) -> tuple[str, str, int]:
"""Retrieve a temporary password to connect to Redshift.
Port is required. If none is provided, default is used for each service.
"""
port = conn.port or 5439
# Pull the custer-identifier from the beginning of the Redshift URL
# ex. my-cluster.ccdre4hpd39h.us-east-1.redshift.amazonaws.com returns my-cluster
cluster_identifier = conn.extra_dejson.get("cluster_identifier")
if not cluster_identifier:
if conn.host:
cluster_identifier = conn.host.split(".", 1)[0]
else:
raise AirflowException("Please set cluster_identifier or host in redshift connection.")
redshift_client = AwsBaseHook(aws_conn_id=self.aws_conn_id, client_type="redshift").conn
# https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/redshift.html#Redshift.Client.get_cluster_credentials
cluster_creds = redshift_client.get_cluster_credentials(
DbUser=conn.login,
DbName=conn.schema,
ClusterIdentifier=cluster_identifier,
AutoCreate=False,
)
token = cluster_creds["DbPassword"]
login = cluster_creds["DbUser"]
return login, token, port
[docs] def get_uri(self) -> str:
"""Overridden to use the Redshift dialect as driver name."""
conn_params = self._get_conn_params()
if "user" in conn_params:
conn_params["username"] = conn_params.pop("user")
# Compatibility: The 'create' factory method was added in SQLAlchemy 1.4
# to replace calling the default URL constructor directly.
create_url = getattr(URL, "create", URL)
return str(create_url(drivername="redshift+redshift_connector", **conn_params))
[docs] def get_sqlalchemy_engine(self, engine_kwargs=None):
"""Overridden to pass Redshift-specific arguments."""
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: str | None = "public") -> list[str] | None:
"""Get the table's primary key.
:param table: Name of the target table
:param schema: Name of the target schema, public by default
:return: Primary key columns list
"""
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:
"""Get 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}
return redshift_connector.connect(**conn_kwargs)
