Source code for airflow.providers.google.cloud.transfers.oracle_to_gcs
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# pylint: disable=c-extension-no-member
import base64
import calendar
from datetime import date, datetime, timedelta
from decimal import Decimal
from typing import Dict
import cx_Oracle
from airflow.providers.google.cloud.transfers.sql_to_gcs import BaseSQLToGCSOperator
from airflow.providers.oracle.hooks.oracle import OracleHook
[docs]class OracleToGCSOperator(BaseSQLToGCSOperator):
"""Copy data from Oracle to Google Cloud Storage in JSON or CSV format.
.. seealso::
For more information on how to use this operator, take a look at the guide:
:ref:`howto/operator:OracleToGCSOperator`
:param oracle_conn_id: Reference to a specific
:ref:`Oracle hook <howto/connection:oracle>`.
:type oracle_conn_id: str
:param ensure_utc: Ensure TIMESTAMP columns exported as UTC. If set to
`False`, TIMESTAMP columns will be exported using the Oracle server's
default timezone.
:type ensure_utc: bool
"""
[docs] type_map = {
cx_Oracle.DB_TYPE_BINARY_DOUBLE: 'DECIMAL',
cx_Oracle.DB_TYPE_BINARY_FLOAT: 'DECIMAL',
cx_Oracle.DB_TYPE_BINARY_INTEGER: 'INTEGER',
cx_Oracle.DB_TYPE_BOOLEAN: 'BOOLEAN',
cx_Oracle.DB_TYPE_DATE: 'TIMESTAMP',
cx_Oracle.DB_TYPE_NUMBER: 'NUMERIC',
cx_Oracle.DB_TYPE_TIMESTAMP: 'TIMESTAMP',
cx_Oracle.DB_TYPE_TIMESTAMP_LTZ: 'TIMESTAMP',
cx_Oracle.DB_TYPE_TIMESTAMP_TZ: 'TIMESTAMP',
}
def __init__(self, *, oracle_conn_id='oracle_default', ensure_utc=False, **kwargs):
super().__init__(**kwargs)
self.ensure_utc = ensure_utc
self.oracle_conn_id = oracle_conn_id
[docs] def query(self):
"""Queries Oracle and returns a cursor to the results."""
oracle = OracleHook(oracle_conn_id=self.oracle_conn_id)
conn = oracle.get_conn()
cursor = conn.cursor()
if self.ensure_utc:
# Ensure TIMESTAMP results are in UTC
tz_query = "SET time_zone = '+00:00'"
self.log.info('Executing: %s', tz_query)
cursor.execute(tz_query)
self.log.info('Executing: %s', self.sql)
cursor.execute(self.sql)
return cursor
[docs] def field_to_bigquery(self, field) -> Dict[str, str]:
field_type = self.type_map.get(field[1], "STRING")
field_mode = "NULLABLE" if not field[6] or field_type == "TIMESTAMP" else "REQUIRED"
return {
'name': field[0],
'type': field_type,
'mode': field_mode,
}
[docs] def convert_type(self, value, schema_type):
"""
Takes a value from Oracle db, and converts it to a value that's safe for
JSON/Google Cloud Storage/BigQuery.
* Datetimes are converted to UTC seconds.
* Decimals are converted to floats.
* Dates are converted to ISO formatted string if given schema_type is
DATE, or UTC seconds otherwise.
* Binary type fields are converted to integer if given schema_type is
INTEGER, or encoded with base64 otherwise. Imported BYTES data must
be base64-encoded according to BigQuery documentation:
https://cloud.google.com/bigquery/data-types
:param value: Oracle db column value
:type value: Any
:param schema_type: BigQuery data type
:type schema_type: str
"""
if value is None:
return value
if isinstance(value, datetime):
value = calendar.timegm(value.timetuple())
elif isinstance(value, timedelta):
value = value.total_seconds()
elif isinstance(value, Decimal):
value = float(value)
elif isinstance(value, date):
if schema_type == "DATE":
value = value.isoformat()
else:
value = calendar.timegm(value.timetuple())
elif isinstance(value, bytes):
if schema_type == "INTEGER":
value = int.from_bytes(value, "big")
else:
value = base64.standard_b64encode(value).decode('ascii')
return value