通过 Python 中的 SSH 连接到 Postgres DB 的问题

Question

I've been given a postgres DB in my uni project in which I have to SSH into the network from which I can then access the DB. I've set up the connection in DBeaver using the SSH tab and it works perfectly fine. However, using Python, I can connect to the SSH just fine, but cannot connect to the DB itself. I've checked with another DB that doesn't require SSH and that works just fine. Here is my code. Note: I've already tried using SSHTunnel, too, to no avail. Also, ignore my quick hack to anonymize my SSH login data, as I didn't find how to use a proper config file with paramiko late at night yesterday...

import os
from psycopg2 import connect, Error
from paramiko import SSHClient
from config import config

with open("ssh_config.txt", "r") as f:
    lines = f.readlines()
    hostname = lines[0].strip()
    username = lines[1].strip()
    password = lines[2].strip()

ssh = SSHClient()
ssh.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
ssh.connect(hostname=hostname, username=username, password=password)
print("SSH connected.")

try:
    params = config()
    conn = connect(**params)
    cursor = conn.cursor()
    print("DB connected.")
    # Print PostgreSQL connection properties.
    print(conn.get_dsn_parameters(), "\n")

    # Print PostgreSQL version.
    cursor.execute("SELECT version();")
    record = cursor.fetchone()
    print("You are connected to - ", record, "\n")

except (Exception, Error) as error:
    print("Error while connecting to PostgreSQL", error)

Any help would be appreciated. Thanks!

Answer 1

I've figured it out myself. Here is the updated code. Basically, I had to forward the remote address to localhost and then connect to localhost instead of the DB address.

from psycopg2 import connect, Error
from sshtunnel import SSHTunnelForwarder
from config import config

with open("ssh_config.txt", "r") as f:
    lines = f.readlines()
    hostname = lines[0].strip()
    username = lines[1].strip()
    password = lines[2].strip()
    remote_bind_address = lines[3].strip()

try:
    with SSHTunnelForwarder(
        (hostname, 22),
        ssh_username=username,
        ssh_password=password,
        remote_bind_address=(remote_bind_address, 5432),
        local_bind_address=("localhost", 8080)) \
            as tunnel:

        tunnel.start()
        print("SSH connected.")

        params = config()
        conn = connect(**params)
        cursor = conn.cursor()
        print("DB connected.")
        # Print PostgreSQL connection properties.
        print(conn.get_dsn_parameters(), "\n")

        # Print PostgreSQL version.
        cursor.execute("SELECT version();")
        record = cursor.fetchone()
        print("You are connected to - ", record, "\n")
        cursor.close()
        conn.close()
        tunnel.close()
        print("DB disconnected.")
except (Exception, Error) as error:
    print("Error while connecting to DB", error)