[Python] In python: oracledb.connect simply hangs, even when the local client succeeds. Why?

I am trying to connect to an Oracle DB using the oracledb connection library and when I try it It simply hangs on with oracledb.connect even when following the documentation.

Here is the sample code. I would expect it to output the system time

#!/usr/bin/env python3
import os
import oracledb

un = os.environ["USER"]
pw = os.environ["PASSWORD"]
tns_entry = os.environ["TNS_ENTRY"]
config_dir = f'{os.environ["PWD"]}/wallets/test/'

print("USERNAME:", un)
print("PASSWORD:", pw)
print("TNS_ENTRY:", tns_entry)
print("TNS_ADMIN:", config_dir)

with open(config_dir+"/tnsnames.ora","r") as f:
print(f.read())

with open(config_dir+"/sqlnet.ora","r") as f:
print(f.read())

with oracledb.connect(
user=un,
password=pw,
dsn=tns_entry,
config_dir=config_dir,
wallet_location=config_dir
) as connection:
with connection.cursor() as cursor:
sql = "select systimestamp from dual"
for (r,) in cursor.execute(sql):
print(r)


Here is the output:

-> % ./dbtest.py
USERNAME: sreapp
PASSWORD: ***
TNS_ENTRY: medium
TNS_ADMIN: /Users/cbongior/dev/oracle/fleetman/wallets/test/
medium = (description= (retry_count=2)(retry_delay=3)(address=(https_proxy=100.92.6.113)(https_proxy_port=3128)(protocol=tcps)(port=1522)(host=zxqgy1nz.adb.us-ashburn-1.oraclecloud.com))(connect_data=(service_name=gea38c0017d364a_sreadwt1_medium.adb.oraclecloud.com))(security=(ssl_server_dn_match=no)))
SQLNET.USE_HTTPS_PROXY=on
WALLET_LOCATION = (SOURCE = (METHOD = file) (METHOD_DATA = (DIRECTORY="$TNS_ADMIN")))
SSL_SERVER_DN_MATCH=no



and in the console, effectively the same steps (confirming setting are valid):

-> % echo $USER
sreapp
(.venv) cbongior@cbongior-mac [16:21:49] [~/dev/oracle/fleetman] [main *]
-> % echo $PASSWORD
****
(.venv) cbongior@cbongior-mac [16:21:54] [~/dev/oracle/fleetman] [main *]
-> % echo $TNS_ENTRY
medium
(.venv) cbongior@cbongior-mac [16:22:05] [~/dev/oracle/fleetman] [main *]
-> % echo $TNS_ADMIN
/Users/cbongior/dev/oracle/fleetman/wallets/test
(.venv) cbongior@cbongior-mac [16:22:21] [~/dev/oracle/fleetman] [main *]
-> % echo $TNS_ADMIN
(.venv) cbongior@cbongior-mac [16:22:32] [~/dev/oracle/fleetman] [main *]
-> % cat $TNS_ADMIN/tnsnames.ora
medium = (description= (retry_count=20)(retry_delay=3)(address=(https_proxy=100.92.6.113)(https_proxy_port=3128)(protocol=tcps)(port=1522)(host=zxqgy1nz.adb.us-ashburn-1.oraclecloud.com))(connect_data=(service_name=gea38c0017d364a_sreadwt1_medium.adb.oraclecloud.com))(security=(ssl_server_dn_match=no)))
[main *]
-> % cat $TNS_ADMIN/sqlnet.ora
SQLNET.USE_HTTPS_PROXY=on
WALLET_LOCATION = (SOURCE = (METHOD = file) (METHOD_DATA = (DIRECTORY="$TNS_ADMIN")))
SSL_SERVER_DN_MATCH=no%



(.venv) cbongior@cbongior-mac [16:22:40] [~/dev/oracle/fleetman] [main *]
-> % sqlplus "${USER}/${PASSWORD}@${TNS_ENTRY}" <<< "select systimestamp from dual;
exit;"


SQL*Plus: Release 19.0.0.0.0 - Production on Tue Mar 25 16:21:01 2025
Version 19.8.0.0.0

Copyright (c) 1982, 2020, Oracle. All rights reserved.

Last Successful login time: Tue Mar 25 2025 16:19:30 -07:00

Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.27.0.1.0

SQL>
SYSTIMESTAMP
---------------------------------------------------------------------------
25-MAR-25 11.21.04.273828 PM +00:00

SQL> Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.27.0.1.0
(.venv) cbongior@cbongior-mac [16:21:05] [~/dev/oracle/fleetman] [main *]


When I move those code to a host behind our firewall (removing the proxy settings), it works immediately:

|main ↑7 S:4 U:3 ?:6 ✗| → dbtest.py
/home/cbongior/.local/lib/python3.6/site-packages/oracledb/__init__.py:39: UserWarning: Python 3.6 is no longer supported by the Python core team. Therefore, support for it is deprecated in python-oracledb and will be removed in a future release
warnings.warn(message)
USERNAME: sreapp
PASSWORD: ****
TNS_ENTRY: medium
TNS_ADMIN: /home/cbongior/dev/oracle/fleetman/wallets/test/
medium = (description= (retry_count=2)(retry_delay=3)(address=(protocol=tcps)(port=1522)(host=zxqgy1nz.adb.us-ashburn-1.oraclecloud.com))(connect_data=(service_name=gea38c0017d364a_sreadwt1_medium.adb.oraclecloud.com))(security=(ssl_server_dn_match=no)))

SQLNET.USE_HTTPS_PROXY=off
WALLET_LOCATION = (SOURCE = (METHOD = file) (METHOD_DATA = (DIRECTORY="$TNS_ADMIN")))
SSL_SERVER_DN_MATCH=no

2025-03-27 00:13:06.250068


It's somehow related to the proxy settings in the tnsnames.ora. I have explicitly set the proxy settings in the connect string, to no luck

Continue reading...