ashb commented on a change in pull request #6604: [AIRFLOW-5920] Neo4j operator and hook URL: https://github.com/apache/airflow/pull/6604#discussion_r360321484
########## File path: airflow/providers/neo4j/hooks/neo4j_hook.py ########## @@ -0,0 +1,138 @@ +# -*- coding: utf-8 -*- +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +""" +This hook provides minimal thin wrapper around the neo4j python library to provide query execution +""" +import csv + +from neo4j import BoltStatementResult, Driver, GraphDatabase, Session + +from airflow.hooks.base_hook import BaseHook + + +class Neo4JHook(BaseHook): + """ + This class enables the neo4j operator to execute queries against a configured neo4j server. + It requires the configuration name as set in Airflow -> Admin -> Connections + + :param n4j_conn_id: Name of connection configured in Airflow + :type n4j_conn_id: str + """ + n4j_conn_id: str + + template_fields = ['n4j_conn_id'] + + def __init__(self, n4j_conn_id: str = 'n4j_default', *args, **kwargs): + self.n4j_conn_id = n4j_conn_id + + @staticmethod + def get_config(n4j_conn_id: str) -> dict: + """ + Obtain the Username + Password from the Airflow connection definition + Store them in _config dictionary as: + *credentials* -- a tuple of username/password eg. ("username", "password") + *host* -- String for Neo4J URI eg. "bolt://1.1.1.1:7687" + + :param n4j_conn_id: Name of connection configured in Airflow + :type n4j_conn_id: str + :return: dictionary with configuration values + :rtype: dict + """ + config: dict = {} + connection_object = Neo4JHook.get_connection(n4j_conn_id) + if connection_object.login and connection_object.host: + config['credentials'] = connection_object.login, connection_object.password + config['host'] = "bolt://{0}:{1}".format(connection_object.host, connection_object.port) + + return config + + @staticmethod + def get_driver(config: dict) -> Driver: + """ + Establish a TCP connection to the server + + :param config: Dictionary containing the host and credentials needed to connect + :type config: dict containing 'host' and 'credentials' keys + :return: Driver connection + :rtype: neo4j.Driver + """ + return GraphDatabase.driver( + uri=config['host'], + auth=config['credentials'] + ) + + @staticmethod + def get_session(driver: Driver) -> Session: + """ + Get a neo4j.session from the driver. + + :param driver Neo4J Driver (established connection to a server) + :type driver: neo4j.Driver + :return: Neo4J session which may contain many transactions + :rtype: neo4j.Session + """ + return driver.session() + + def run_query(self, cypher_query: str, parameters=None) -> BoltStatementResult: + """ + Uses a session to execute submit a query for execution + + :param cypher_query: Cypher query eg. MATCH (a) RETURN (a) + :type cypher_query: str + :param parameters: Optional list of parameters to use with the query + :type parameters: list[str] + :return: Result of query execution (nodes & relationships) + :rtype: neo4j.BoltStatementResult see https://neo4j.com/docs/api/python-driver/current/results.html + """ + neo4j_config: dict = Neo4JHook.get_config(self.n4j_conn_id) + neo4j_driver: Driver = Neo4JHook.get_driver(neo4j_config) + neo4j_session: Session = Neo4JHook.get_session(neo4j_driver) Review comment: The more common pattern here would be something like: ``` neo4j_session = self.get_conn() ``` (or call it get_session) And then that one method will do all of these three steps in one. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
