Thursday, October 27, 2022

[SOLVED] Paramiko ssh client ssh_stderr comes as 'sudo: no tty present and no askpass program specified' while executing docker command in Python

Issue

I tried to read the docker container logs using an ssh connection.

def test_read_ssh():
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(IPAddress, username='usr', password='pwd')
    ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command('sudo docker logs -f 16e --tail 100')
    container_logs = ssh_stdout.read().decode("utf-8")

When reading the output it comes as empty string.

In the line where I defined 'ssh_stdin, ssh_stdout, ssh_stderr' when I debug it shows message as below

<paramiko.ChannelFile from <paramiko.Channel 0 (closed) -> <paramiko.Transport at 0x93ce2310 (cipher aes128-ctr, 128 bits) (active; 0 open channel(s))>>>

SSH connection works fine in the machine where I ran the code and I could see the logs.

I tried reading the 'ssh_stderr' as 'ssh_stderr.readlines()' and the output was as below

'sudo: no tty present and no askpass program specified '

I tried executing 'ls' command as below and that works fine!

ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command('ls')

The ssh_stdout output comes below

Desktop Documents Downloads examples.desktop Music Pictures Public Templates Videos

Then the issue is with docker commands only!

For 'sudo' I need to provide a password. Not sure how to do this.

Python Version: 3.9.13

Paramiko Version: 2.11.0


Solution

The problem was due to a password request that comes immediately after 'sudo' command.

For this, I need to enter a Password and then the problem was solved!

def test_read_ssh():
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(IPAddress, username='usr', password='pwd')
    ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command('sudo docker logs -f 16e --tail 100', get_pty=True)
    ssh_stdin.write('pwd\n')
    ssh_stdin.flush()
    container_logs = ssh_stdout.read().decode("utf-8")

Reference: https://www.youtube.com/watch?v=fVOFWehhc38

Thanks!



Answered By - KBNanda
Answer Checked By - Mary Flores (WPSolving Volunteer)
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