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"""Transfers data from AWS Redshift into a S3 Bucket."""
from __future__ import annotations
import re
from typing import TYPE_CHECKING, Iterable, Mapping, Sequence
from airflow.exceptions import AirflowException
from airflow.models import BaseOperator
from airflow.providers.amazon.aws.hooks.redshift_data import RedshiftDataHook
from airflow.providers.amazon.aws.hooks.redshift_sql import RedshiftSQLHook
from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.amazon.aws.utils.redshift import build_credentials_block
if TYPE_CHECKING:
from airflow.utils.context import Context
[docs]class RedshiftToS3Operator(BaseOperator):
"""
Execute an UNLOAD command to s3 as a CSV with headers.
.. seealso::
For more information on how to use this operator, take a look at the guide:
:ref:`howto/operator:RedshiftToS3Operator`
:param s3_bucket: reference to a specific S3 bucket
: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
:param schema: reference to a specific schema in redshift database,
used when ``table`` param provided and ``select_query`` param not provided.
Do not provide when unloading a temporary table
:param table: reference to a specific table in redshift database,
used when ``schema`` param provided and ``select_query`` param not provided
:param select_query: custom select query to fetch data from redshift database,
has precedence over default query `SELECT * FROM ``schema``.``table``
:param redshift_conn_id: reference to a specific redshift database
:param aws_conn_id: reference to a specific S3 connection
If the AWS connection contains 'aws_iam_role' in ``extras``
the operator will use AWS STS credentials with a token
https://docs.aws.amazon.com/redshift/latest/dg/copy-parameters-authorization.html#copy-credentials
:param verify: Whether 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.
:param unload_options: reference to a list of UNLOAD options
: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.
:param include_header: If set to True the s3 file contains the header columns.
:param parameters: (optional) the parameters to render the SQL query with.
:param table_as_file_name: If set to True, the s3 file will be named as the table.
Applicable when ``table`` param provided.
:param redshift_data_api_kwargs: If using the Redshift Data API instead of the SQL-based connection,
dict of arguments for the hook's ``execute_query`` method.
Cannot include any of these kwargs: ``{'sql', 'parameters'}``
"""
[docs] template_fields: Sequence[str] = (
"s3_bucket",
"s3_key",
"schema",
"table",
"unload_options",
"select_query",
"redshift_conn_id",
"redshift_data_api_kwargs",
)
[docs] template_ext: Sequence[str] = (".sql",)
[docs] template_fields_renderers = {"select_query": "sql"}
def __init__(
self,
*,
s3_bucket: str,
s3_key: str,
schema: str | None = None,
table: str | None = None,
select_query: str | None = None,
redshift_conn_id: str = "redshift_default",
aws_conn_id: str | None = "aws_default",
verify: bool | str | None = None,
unload_options: list | None = None,
autocommit: bool = False,
include_header: bool = False,
parameters: Iterable | Mapping | None = None,
table_as_file_name: bool = True, # Set to True by default for not breaking current workflows
redshift_data_api_kwargs: dict | None = None,
**kwargs,
) -> None:
super().__init__(**kwargs)
self.s3_bucket = s3_bucket
self.s3_key = s3_key
self.schema = schema
self.table = table
self.redshift_conn_id = redshift_conn_id
self.aws_conn_id = aws_conn_id
self.verify = verify
self.unload_options = unload_options or []
self.autocommit = autocommit
self.include_header = include_header
self.parameters = parameters
self.table_as_file_name = table_as_file_name
self.redshift_data_api_kwargs = redshift_data_api_kwargs or {}
self.select_query = select_query
def _build_unload_query(
self, credentials_block: str, select_query: str, s3_key: str, unload_options: str
) -> str:
# Un-escape already escaped queries
select_query = re.sub(r"''(.+?)''", r"'\1'", select_query)
return f"""
UNLOAD ($${select_query}$$)
TO 's3://{self.s3_bucket}/{s3_key}'
credentials
'{credentials_block}'
{unload_options};
"""
@property
[docs] def default_select_query(self) -> str | None:
if not self.table:
return None
if self.schema:
table = f"{self.schema}.{self.table}"
else:
# Relevant when unloading a temporary table
table = self.table
return f"SELECT * FROM {table}"
@property
[docs] def use_redshift_data(self):
return bool(self.redshift_data_api_kwargs)
[docs] def execute(self, context: Context) -> None:
if self.table and self.table_as_file_name:
self.s3_key = f"{self.s3_key}/{self.table}_"
self.select_query = self.select_query or self.default_select_query
if self.select_query is None:
raise ValueError("Please specify either a table or `select_query` to fetch the data.")
if self.include_header and "HEADER" not in [uo.upper().strip() for uo in self.unload_options]:
self.unload_options = [*self.unload_options, "HEADER"]
if self.use_redshift_data:
redshift_data_hook = RedshiftDataHook(aws_conn_id=self.redshift_conn_id)
for arg in ["sql", "parameters"]:
if arg in self.redshift_data_api_kwargs:
raise AirflowException(f"Cannot include param '{arg}' in Redshift Data API kwargs")
else:
redshift_sql_hook = RedshiftSQLHook(redshift_conn_id=self.redshift_conn_id)
conn = S3Hook.get_connection(conn_id=self.aws_conn_id) if self.aws_conn_id else None
if conn and conn.extra_dejson.get("role_arn", False):
credentials_block = f"aws_iam_role={conn.extra_dejson['role_arn']}"
else:
s3_hook = S3Hook(aws_conn_id=self.aws_conn_id, verify=self.verify)
credentials = s3_hook.get_credentials()
credentials_block = build_credentials_block(credentials)
unload_options = "\n\t\t\t".join(self.unload_options)
unload_query = self._build_unload_query(
credentials_block, self.select_query, self.s3_key, unload_options
)
self.log.info("Executing UNLOAD command...")
if self.use_redshift_data:
redshift_data_hook.execute_query(
sql=unload_query, parameters=self.parameters, **self.redshift_data_api_kwargs
)
else:
redshift_sql_hook.run(unload_query, self.autocommit, parameters=self.parameters)
self.log.info("UNLOAD command complete...")
[docs] def get_openlineage_facets_on_complete(self, task_instance):
"""Implement on_complete as we may query for table details."""
from airflow.providers.amazon.aws.utils.openlineage import (
get_facets_from_redshift_table,
get_identity_column_lineage_facet,
)
from airflow.providers.common.compat.openlineage.facet import (
Dataset,
Error,
ExtractionErrorRunFacet,
)
from airflow.providers.openlineage.extractors import OperatorLineage
output_dataset = Dataset(
namespace=f"s3://{self.s3_bucket}",
name=self.s3_key,
)
if self.use_redshift_data:
redshift_data_hook = RedshiftDataHook(aws_conn_id=self.redshift_conn_id)
database = self.redshift_data_api_kwargs.get("database")
identifier = self.redshift_data_api_kwargs.get(
"cluster_identifier", self.redshift_data_api_kwargs.get("workgroup_name")
)
port = self.redshift_data_api_kwargs.get("port", "5439")
authority = f"{identifier}.{redshift_data_hook.region_name}:{port}"
else:
redshift_sql_hook = RedshiftSQLHook(redshift_conn_id=self.redshift_conn_id)
database = redshift_sql_hook.conn.schema
authority = redshift_sql_hook.get_openlineage_database_info(redshift_sql_hook.conn).authority
if self.select_query == self.default_select_query:
if self.use_redshift_data:
input_dataset_facets = get_facets_from_redshift_table(
redshift_data_hook, self.table, self.redshift_data_api_kwargs, self.schema
)
else:
input_dataset_facets = get_facets_from_redshift_table(
redshift_sql_hook, self.table, {}, self.schema
)
input_dataset = Dataset(
namespace=f"redshift://{authority}",
name=f"{database}.{self.schema}.{self.table}" if database else f"{self.schema}.{self.table}",
facets=input_dataset_facets,
)
# If default select query is used (SELECT *) output file matches the input table.
output_dataset.facets = {
"schema": input_dataset_facets["schema"],
"columnLineage": get_identity_column_lineage_facet(
field_names=[field.name for field in input_dataset_facets["schema"].fields],
input_datasets=[input_dataset],
),
}
return OperatorLineage(inputs=[input_dataset], outputs=[output_dataset])
try:
from airflow.providers.openlineage.sqlparser import SQLParser, from_table_meta
except ImportError:
return OperatorLineage(outputs=[output_dataset])
run_facets = {}
parse_result = SQLParser(dialect="redshift", default_schema=self.schema).parse(self.select_query)
if parse_result.errors:
run_facets["extractionError"] = ExtractionErrorRunFacet(
totalTasks=1,
failedTasks=1,
errors=[
Error(
errorMessage=error.message,
stackTrace=None,
task=error.origin_statement,
taskNumber=error.index,
)
for error in parse_result.errors
],
)
input_datasets = []
for in_tb in parse_result.in_tables:
ds = from_table_meta(in_tb, database, f"redshift://{authority}", False)
schema, table = ds.name.split(".")[-2:]
if self.use_redshift_data:
input_dataset_facets = get_facets_from_redshift_table(
redshift_data_hook, table, self.redshift_data_api_kwargs, schema
)
else:
input_dataset_facets = get_facets_from_redshift_table(redshift_sql_hook, table, {}, schema)
ds.facets = input_dataset_facets
input_datasets.append(ds)
return OperatorLineage(inputs=input_datasets, outputs=[output_dataset], run_facets=run_facets)