ocx_Oracle ORA-12541 tns no listener

Question

I try to connect to a remote oracle server by cx_Oracle:

db = cx_Oracle.connect('username', 'password', dsn_tns)

but it says databaseError: ORA-12541 tns no listener

Answer 1

I was able to connect via db client (e.g datagrip), but I got the No Listener error when i connect from python script because my original connection string did not specify the port. I was following the cx_Oracle doc

This post helped me by specifying the port this way:

ip = '192.168.0.1'
port = 1521
SID = 'YOURSIDHERE'
dsn_tns = cx_Oracle.makedsn(ip, port, SID)

db = cx_Oracle.connect('username', 'password', dsn_tns)