setting `client_identifier` via cx_Oracle and sqlalchemy

Question

I'm running a flask-rest-jsonapi application on top of Flask, sqlalchemy, and cx_Oracle. One requirement of this project is that the connection property client_identifier , made available via cx_Oracle ( relevant documentation ), be modifiable based on a value sent in a JWT with each client request. We need to be able to write to this property because our internal auditing tables make use of it to track changes made by individual users.

In PHP, setting this value is straightforward using oci8, and has worked great for us in the past.

However, I have been unable to figure out how to set the same property using this new application structure. In cx_Oracle, the client_identifier property is a 'write-only' property, so it's difficult to verify that the value is set correctly without going to the backend and examining the db session properties. You access this property via the sqlalchemy raw_connection object.

Beyond being difficult to read, setting the value has no effect. We get the desired client identifier value from the JWT passed in with each request and attempt to set it on the raw connection object. While the action of setting the value throws no error, the value does not show up on the backend for the relevant session, ie the client_identifier property is null when viewing sessions on the db side.

from flask import Flask, jsonify, request
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)

db = SQLAlchemy(app)

# the client_identifier property is available at db.engine.raw_connection()

# attempt to set the client_identifier property
raw_conn = db.engine.raw_connection()
raw_conn.client_identifier = 'USER_210'

# execute some sql using raw_conn.cursor()...
# the client identifier value on the db side for this request is null

Is the approach shown above the correct way to set the client_identifier? If so, why isn't USER_210 listed in the client_identifier column when querying the backend session table using the v$session view?

Answer 1

In pure cx_Oracle, this works for me:

import cx_Oracle

db = cx_Oracle.connect("system", "oracle", "localhost/orclpdb")
db.client_identifier = 'this-is-me'
cursor = db.cursor()
cursor.execute("select username, client_identifier from v$session where username = 'SYSTEM'")
v = cursor.fetchone()
print(v)

The result is:

$ python3 q1.py 
('SYSTEM', 'this-is-me')

I don't have the setup to test your exact scenario.