Collect output from top command using Paramiko in Python

Question

Here I am trying to execute ssh commands and print the output. It works fine except the command top. Any lead how to collect the output from top ?

import paramiko
from paramiko import SSHClient, AutoAddPolicy, RSAKey

output_cmd_list = ['ls','top']

ssh = paramiko.SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(hostname_ip, port, username, password)

for each_command in output_cmd_list:
    stdin, stdout, stderr = ssh.exec_command(each_command)
    stdout.channel.recv_exit_status()
    outlines = stdout.readlines()
    resp = ''.join(outlines)
    print(resp)    

Answer 1

The top is a fancy command that requires a terminal/PTY. While you can enable the terminal emulation using get_pty argument of SSHClient.exec_command, it would get you lot of garbage with ANSI escape codes. I'm not sure you want that. The terminal is for interactive human use only. If you want to automate things, do not mess with terminal.

Rather, execute the top in batch mode:

top -b -n 1

See get top output for non interactive shell.

Answer 2

There is an option in exe_command, [get_pty=True] which provides pseudo-terminal. Here I have got an output by adding the same in my code.

import paramiko
from paramiko import SSHClient, AutoAddPolicy, RSAKey

output_cmd_list = ['ls','top']

ssh = paramiko.SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(hostname_ip, port, username, password)

for command in output_cmd_list:
    stdin, stdout, stderr = ssh.exec_command(command,get_pty=True)
    stdout.channel.recv_exit_status()
    outlines = stdout.readlines()
    resp = ''.join(outlines)
    print(resp)