python中的嵌套telnet-telnet中的Telnet

Question

I am trying to automate a process wherein I would telnet to RouterA and from that RouterA I would again telnet to RouterB. I have the code to telnet to RouterA and its working perfectly fine but I am not able to telnet from RouterA to RouterB. The session becomes unresponsive. I am doing something wrong. Can someone please guide me?

Below is my code:

import os
import telnetlib
import re

def telNetCall():
 host  = "15.xx.xx.xx"
 user  = "admin"
 password = "password"
 enable_password = "enable_password"
 telnet  = telnetlib.Telnet(host) 


 telnet.read_until('Username: ', 3)
 telnet.write(user + '\r')
 telnet.read_until('Password: ', 3)
 telnet.write(password + '\r')
 telnet.write('enable' + '\r\n')
 telnet.write(enable_password + '\r\n')
 telnet.read_until("#")
 telnet.write("telnet 20.xx.xx.xx" + '\r\n')
 telnet.read_until('Username: ', 3)
 telnet.write(user + '\r')
 telnet.read_until('Password: ', 3)
 telnet.write(password + '\r')
 telnet.write('enable' + '\r\n')
 telnet.write(enable_password + '\r\n')
 telnet.write("show logg"+ "\r\n")
 telnet.write('exit' + '\r')
 a = telnet.read_all() 
 f = open(host, 'w')
 f.write(str(a))
telNetCall()

Code is working but it is taking very long time to execute. I believe I am doing something which is not allowing the code to run efficiently. If there are any issues with the code suggestions are welcome. Any help is greatly appreciated.

I have figured out the error and now its working fine for me. It hardly takes 5 seconds now.

Answer 1

You can use another read_xx() functions like read_until() or read_eager() .

See comment of Telnet.read_all() below:

Read all data until EOF; block until connection closed.