Neo4j connector in python keeps mentioning the legacy warning for closing the session

Question

i have the following code in my class:

from neo4j import GraphDatabase
from typing import Dict, List, Optional, Tuple, Any
import re
from DatabaseConnector import DatabaseConnector
import logging

class Neo4jConnector(DatabaseConnector):
    def __init__(self, uri: str, user: str, password: str):
        self._driver = GraphDatabase.driver(uri, auth=(user, password))

    def run_query(self, query: str, parameters: Optional[Dict[str, Any]] = None) -> List[Dict[str, Any]]:
        with self._driver.session() as session:
            result = session.run(query, parameters)
            logging.debug(f"The following query was sent: {query} with parameters {parameters}")
            return result.data()

but when u run it, i get the following error message:

usr/local/python/3.10.4/lib/python3.10/site-packages/neo4j/_sync/driver.py:457: DeprecationWarning: Relying on Driver's destructor to close the session is deprecated. Please make sure to close the session. Use it as a context (`with` statement) or make sure to call `.close()` explicitly. Future versions of the driver will not close drivers automatically.

I tried:

enclosing the run in a with statement (see code above)
closing the driver manually, which resulted in another error: "neo4j.exceptions.ServiceUnavailable: Failed to read from closed connection"
closing the session manually (which is useless I suppose as it is within the with statement…)

    def run_query(self, query: str, parameters: Optional[Dict[str, Any]] = None) -> List[Dict[str, Any]]:
        with self._driver.session() as session:
            result = session.run(query, parameters)
            logging.debug(f"The following query was sent: {query} with parameters {parameters}")
            data = result.data()
            session.close()
            return data

as this is the only place I am using the driver to connect and run queries to neo4j, this is confusing to say the least

Asked By: Pro Grammer S

||

Source

Answer 1

The warning is about the driver not being closed, not the session.

One way to address this is to create (and close) the driver inside run_query:

class Neo4jConnector(DatabaseConnector):
    def __init__(self, uri: str, user: str, password: str):
        self._uri = uri
        self._auth = (user, password)

    def run_query(self, query: str, parameters: Optional[Dict[str, Any]] = None) -> List[Dict[str, Any]]:
        with (
            neo4j.GraphDatabase.driver(self._uri, auth=self._auth) as driver,
            driver.session() as session
        ):
            result = session.run(query, parameters)
            logging.debug(f"The following query was sent: {query} with parameters {parameters}")
            return result.data()

Or, if you are going to be performing multiple queries with the same connector instance, you should consider using the __enter__ and __exit__ pattern shown in this answer.

Answered By: cybersam

Neo4j connector in python keeps mentioning the legacy warning for closing the session

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