Source code for airflow.hooks.base_hook

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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import os
import random

from airflow.models.connection import Connection
from airflow.exceptions import AirflowException
from airflow.utils.db import provide_session
from airflow.utils.log.logging_mixin import LoggingMixin

[docs]class BaseHook(LoggingMixin): """ Abstract base class for hooks, hooks are meant as an interface to interact with external systems. MySqlHook, HiveHook, PigHook return object that can handle the connection and interaction to specific instances of these systems, and expose consistent methods to interact with them. """ def __init__(self, source): pass @classmethod @provide_session
[docs] def _get_connections_from_db(cls, conn_id, session=None): db = ( session.query(Connection) .filter(Connection.conn_id == conn_id) .all() ) session.expunge_all() if not db: raise AirflowException( "The conn_id `{0}` isn't defined".format(conn_id)) return db
[docs] def _get_connection_from_env(cls, conn_id): environment_uri = os.environ.get(CONN_ENV_PREFIX + conn_id.upper()) conn = None if environment_uri: conn = Connection(conn_id=conn_id, uri=environment_uri) return conn
[docs] def get_connections(cls, conn_id): conn = cls._get_connection_from_env(conn_id) if conn: conns = [conn] else: conns = cls._get_connections_from_db(conn_id) return conns
[docs] def get_connection(cls, conn_id): conn = random.choice(cls.get_connections(conn_id)) if log = LoggingMixin().log"Using connection to: %s", conn.debug_info()) return conn
[docs] def get_hook(cls, conn_id): connection = cls.get_connection(conn_id) return connection.get_hook()
[docs] def get_conn(self): raise NotImplementedError()
[docs] def get_records(self, sql): raise NotImplementedError()
[docs] def get_pandas_df(self, sql): raise NotImplementedError()
[docs] def run(self, sql): raise NotImplementedError()