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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 02:08:31 GMT
tfindlay-tw commented on a change in pull request #6604: [AIRFLOW-5920] *DRAFT* Neo4j operator
and hook

 File path: airflow/contrib/operators/
 @@ -0,0 +1,92 @@
+# -*- 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
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from airflow.models import BaseOperator
+from airflow.utils.decorators import apply_defaults
+from airflow.exceptions import AirflowException
+from airflow.contrib.hooks.neo4j_hook import Neo4JHook
+import csv
+class Neo4JOperator(BaseOperator):
+    """
+    Neo4JOperator to interact and perform action on Neo4J graph database.
+    This operator is designed to use Neo4J Python driver:
+    :param cypher_query: required cypher query to be executed on the Neo4J database
+    :type cypher_query: str
+    :param output_filename: required filename to produce with output from the query
+    :type output_filename: str
+    :param n4j_conn_id: reference to a pre-defined Neo4J Connection
+    :type n4j_conn_id: str
+    :param fail_on_no_results: True/False flag to indicate if it should fail the task if
no results
+    :type fail_on_no_results: bool
+    """
+    _cypher_query = None
+    _output_filename = None
+    _n4j_conn_id = None
+    _fail_on_no_results = None
+    @apply_defaults
+    def __init__(self,
+                 cypher_query,
+                 output_filename,
+                 n4j_conn_id='n4j_default',
+                 fail_on_no_results=False,
+                 *args,
+                 **kwargs):
+        super().__init__(*args, **kwargs)
+        self._output_filename = output_filename
+        self._cypher_query = cypher_query
+        self._n4j_conn_id = n4j_conn_id
+        self._fail_on_no_results = fail_on_no_results
+    def execute(self, context):
+        hook = Neo4JHook(n4j_conn_id=self._n4j_conn_id)
+        if self._cypher_query is not None:
+            result = hook.run_query(cypher_query=self._cypher_query)
+        else:
+            raise AirflowException("cypher_query is missing.")
 Review comment:
   Sure, at one point, I considered making it optional. Queries could be read in from files
or other sources, but then simplified it to just accept a string. Have removed this to reflect
how it is designed to operate right now. Complexity can be added later if needed.

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