Source code for airflow.operators.redshift_to_s3_operator

# -*- coding: utf-8 -*-
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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# http://www.apache.org/licenses/LICENSE-2.0
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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: string :param table: reference to a specific table in redshift database :type table: string :param s3_bucket: reference to a specific S3 bucket :type s3_bucket: string :param s3_key: reference to a specific S3 key :type s3_key: string :param redshift_conn_id: reference to a specific redshift database :type redshift_conn_id: string :param aws_conn_id: reference to a specific S3 connection :type aws_conn_id: string :param options: reference to a list of UNLOAD options :type options: list """ template_fields = () template_ext = () ui_color = '#ededed' @apply_defaults def __init__( self, schema, table, s3_bucket, s3_key, redshift_conn_id='redshift_default', aws_conn_id='aws_default', unload_options=tuple(), autocommit=False, parameters=None, *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.unload_options = unload_options self.autocommit = autocommit self.parameters = parameters def execute(self, context): self.hook = PostgresHook(postgres_conn_id=self.redshift_conn_id) self.s3 = S3Hook(aws_conn_id=self.aws_conn_id) a_key, s_key = self.s3.get_credentials() unload_options = '\n\t\t\t'.join(self.unload_options) self.log.info("Retrieving headers from %s.%s...", self.schema, self.table) columns_query = """SELECT column_name FROM information_schema.columns WHERE table_schema = '{0}' AND table_name = '{1}' ORDER BY ordinal_position """.format(self.schema, self.table) cursor = self.hook.get_conn().cursor() cursor.execute(columns_query) rows = cursor.fetchall() columns = map(lambda row: row[0], rows) column_names = ', '.join(map(lambda c: "\\'{0}\\'".format(c), columns)) column_castings = ', '.join(map(lambda c: "CAST({0} AS text) AS {0}".format(c), columns)) unload_query = """ UNLOAD ('SELECT {0} UNION ALL SELECT {1} FROM {2}.{3} ORDER BY 1 DESC') TO 's3://{4}/{5}/{3}_' with credentials 'aws_access_key_id={6};aws_secret_access_key={7}' {8}; """.format(column_names, column_castings, self.schema, self.table, self.s3_bucket, self.s3_key, a_key, s_key, unload_options) self.log.info('Executing UNLOAD command...') self.hook.run(unload_query, self.autocommit) self.log.info("UNLOAD command complete...")