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Subject [GitHub] [airflow] tfindlay-tw commented on a change in pull request #6604: [AIRFLOW-5920] *DRAFT* Neo4j operator and hook
Date Mon, 25 Nov 2019 02:06:53 GMT
tfindlay-tw commented on a change in pull request #6604: [AIRFLOW-5920] *DRAFT* Neo4j operator
and hook
URL: https://github.com/apache/airflow/pull/6604#discussion_r349968925
 
 

 ##########
 File path: airflow/contrib/hooks/neo4j_hook.py
 ##########
 @@ -0,0 +1,93 @@
+# -*- 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.
+
+from airflow.exceptions import AirflowException
+from airflow.hooks.base_hook import BaseHook
+from neo4j import GraphDatabase
+
+
+class Neo4JHook(BaseHook):
+    """
+    Interact with Neo4J.
+    This class is a thin wrapper around the neo4j python library.
+    """
+    _n4j_conn_id = None
+
+    def __init__(self, n4j_conn_id='n4j_default', *args, **kwargs):
+        super().__init__()
+        self._n4j_conn_id = n4j_conn_id
+
+    @staticmethod
+    def get_config(n4j_conn_id):
+        """
+        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"
+        :return: dictionary with configuration values
+        """
+        config = {}
+        if n4j_conn_id:
+            # Initialize with empty dictionary
+            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)
+        else:
+            raise AirflowException("No Neo4J connection: {}".format(n4j_conn_id))
+
+        return config
+
+    @staticmethod
+    def get_driver(config):
+        """
+        Establish a TCP connection to the server
+        """
+        # Check if we already have a driver we can re-use before creating a new one
+        return GraphDatabase.driver(
+            uri=config['host'],
+            auth=config['credentials']
+        )
+
+    @staticmethod
+    def get_session(driver):
+        """
+        Get a neo4j.session from the driver.
+        """
+        # Check if we already have a session we can re-use before creating a new one
+        return driver.session()
+
+    def run_query(self, cypher_query, parameters=None):
+        """
+        Uses a session to execute submit a query for execution
+        :param cypher_query: Cypher query eg. MATCH (a) RETURN (a)
+        :param parameters: Optional list of parameters to use with the query
+        :return: neo4j.BoltStatementResult see https://neo4j.com/docs/api/python-driver/current/results.html
+        """
+        a = Neo4JHook.get_config(self._n4j_conn_id)
+        b = Neo4JHook.get_driver(a)
+        c = Neo4JHook.get_session(b)
 
 Review comment:
   Yes, apologies, I did name them better initially, but during testing I did this, they should
be fixed up now.

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