Source code for airflow.operators.redshift_to_s3_operator
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"""
Transfers data from AWS Redshift into a S3 Bucket.
"""
from airflow.hooks.postgres_hook import PostgresHook
from airflow.hooks.S3_hook import S3Hook
from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults
[docs]class RedshiftToS3Transfer(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
"""
@apply_defaults
def __init__( # pylint: disable=too-many-arguments
self,
schema,
table,
s3_bucket,
s3_key,
redshift_conn_id='redshift_default',
aws_conn_id='aws_default',
verify=None,
unload_options=tuple(),
autocommit=False,
include_header=False,
table_as_file_name=True, # Set to True by default for not breaking current workflows
*args, **kwargs):
super(RedshiftToS3Transfer, self).__init__(*args, **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
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):
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 = '{}/{}_'.format(self.s3_key, self.table) if self.table_as_file_name else self.s3_key
select_query = "SELECT * FROM {schema}.{table}".format(schema=self.schema, table=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...")