Source code for airflow.providers.amazon.aws.transfers.redshift_to_s3
#
# 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.
"""Transfers data from AWS Redshift into a S3 Bucket."""
from typing import List, Optional, Union
from airflow.models import BaseOperator
from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.postgres.hooks.postgres import PostgresHook
from airflow.utils.decorators import apply_defaults
[docs]class RedshiftToS3Operator(BaseOperator):
"""
Executes an UNLOAD command to s3 as a CSV with headers
:param schema: reference to a specific schema in redshift database
:type schema: str
:param table: reference to a specific table in redshift database
:type table: str
:param s3_bucket: reference to a specific S3 bucket
:type s3_bucket: str
:param s3_key: reference to a specific S3 key. If ``table_as_file_name`` is set
to False, this param must include the desired file name
:type s3_key: str
:param redshift_conn_id: reference to a specific redshift database
:type redshift_conn_id: str
:param aws_conn_id: reference to a specific S3 connection
:type aws_conn_id: str
:param verify: Whether or not to verify SSL certificates for S3 connection.
By default SSL certificates are verified.
You can provide the following values:
- ``False``: do not validate SSL certificates. SSL will still be used
(unless use_ssl is False), but SSL certificates will not be
verified.
- ``path/to/cert/bundle.pem``: A filename of the CA cert bundle to uses.
You can specify this argument if you want to use a different
CA cert bundle than the one used by botocore.
:type verify: bool or str
:param unload_options: reference to a list of UNLOAD options
:type unload_options: list
:param autocommit: If set to True it will automatically commit the UNLOAD statement.
Otherwise it will be committed right before the redshift connection gets closed.
:type autocommit: bool
:param include_header: If set to True the s3 file contains the header columns.
:type include_header: bool
:param table_as_file_name: If set to True, the s3 file will be named as the table
:type table_as_file_name: bool
"""
[docs] template_fields = ('s3_bucket', 's3_key', 'schema', 'table', 'unload_options')
@apply_defaults
def __init__( # pylint: disable=too-many-arguments
self,
*,
schema: str,
table: str,
s3_bucket: str,
s3_key: str,
redshift_conn_id: str = 'redshift_default',
aws_conn_id: str = 'aws_default',
verify: Optional[Union[bool, str]] = None,
unload_options: Optional[List] = None,
autocommit: bool = False,
include_header: bool = False,
table_as_file_name: bool = True, # Set to True by default for not breaking current workflows
**kwargs,
) -> None:
super().__init__(**kwargs)
self.schema = schema
self.table = table
self.s3_bucket = s3_bucket
self.s3_key = s3_key
self.redshift_conn_id = redshift_conn_id
self.aws_conn_id = aws_conn_id
self.verify = verify
self.unload_options = unload_options or [] # type: List
self.autocommit = autocommit
self.include_header = include_header
self.table_as_file_name = table_as_file_name
if self.include_header and 'HEADER' not in [uo.upper().strip() for uo in self.unload_options]:
self.unload_options = list(self.unload_options) + [
'HEADER',
]
[docs] def execute(self, context) -> None:
postgres_hook = PostgresHook(postgres_conn_id=self.redshift_conn_id)
s3_hook = S3Hook(aws_conn_id=self.aws_conn_id, verify=self.verify)
credentials = s3_hook.get_credentials()
unload_options = '\n\t\t\t'.join(self.unload_options)
s3_key = f'{self.s3_key}/{self.table}_' if self.table_as_file_name else self.s3_key
select_query = f"SELECT * FROM {self.schema}.{self.table}"
unload_query = """
UNLOAD ('{select_query}')
TO 's3://{s3_bucket}/{s3_key}'
with credentials
'aws_access_key_id={access_key};aws_secret_access_key={secret_key}'
{unload_options};
""".format(
select_query=select_query,
s3_bucket=self.s3_bucket,
s3_key=s3_key,
access_key=credentials.access_key,
secret_key=credentials.secret_key,
unload_options=unload_options,
)
self.log.info('Executing UNLOAD command...')
postgres_hook.run(unload_query, self.autocommit)
self.log.info("UNLOAD command complete...")