python3.5 paramiko failed with hostname - ssh

Question

Please help me to correct my script. My script checks the ssh login of a host and displays success/failure based on result. It fails when I give wrong hostname.
Code is as of below :
[root#test1 script]# cat param.py
import multiprocessing
import paramiko
import random
import threading
import time
host_name = "test2"
print ("Checking hostname :"+str(host_name))
file = open('output_file','a')
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
ssh.connect(host_name, username='root', password='test')
print ("success")
file.write("success:"+str(host_name+"\n"))
except paramiko.SSHException:
print ("Connection Failed")
file.write("failed:"+str(host_name+"\n"))
quit()
stdin,stdout,stderr = ssh.exec_command("hostname&&uptime")
for line in stdout.readlines():
print (line.strip())
ssh.close()
It works fine when the correct username/password given :
[root#test1 script]# python3 param.py
Checking hostname :test2
success
test2
12:31:49 up 83 days, 2:56, 2 users, load average: 0.00, 0.01, 0.05
It works fine when the wrong password is given. I have changed the password to a wrong one in the script and it says connection failed as expected.
root#test1 script]# python3 param.py
Checking hostname :test2
Connection Failed
Now my question, when I change the hostname to something doenot exist, paramiko fails and lot of errors pop up.
[root#test1 script]# python3 param.py
Checking hostname :invalidtest2
Traceback (most recent call last):
File "param.py", line 16, in <module>
ssh.connect(host_name, username='root', password='test')
File "/root/usr/local/lib/python3.5/site-packages/paramiko/client.py", line 301, in connect
to_try = list(self._families_and_addresses(hostname, port))
File "/root/usr/local/lib/python3.5/site-packages/paramiko/client.py", line 199, in _families_and_addresses
hostname, port, socket.AF_UNSPEC, socket.SOCK_STREAM)
File "/root/usr/local/lib/python3.5/socket.py", line 728, in getaddrinfo
for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -2] Name or service not known
How can I get message that the connection failed ? I'm using python3.5

Answer 1

It is not good idea to keep the passwords stored in the script itself. Modified the script so that it takes the hostnames from a file and writes the output to different files
#!/bin/python3
import threading, time, paramiko, socket, getpass
from queue import Queue
start_time1 = time.time()
locke1 = threading.Lock()
q = Queue()
#Check the login
def check_hostname(host_name, pw_r):
with locke1:
print ("Checking hostname :"+str(host_name)+" with " + threading.current_thread().name)
file_output = open('output_file','a')
file_success = open('success_file','a')
file_failed = open('failed_file','a')
file_error = open('error_file','a')
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
ssh.connect(host_name, username='root', password=pw_r)
#print ("Success")
file_success.write(str(host_name+"\n"))
file_success.close()
file_output.write("success: "+str(host_name+"\n"))
file_output.close()
# printing output if required from remote machine
#stdin,stdout,stderr = ssh.exec_command("hostname&&uptime")
#for line in stdout.readlines():
# print (line.strip())
except paramiko.SSHException:
# print ("error")
file_failed.write(str(host_name+"\n"))
file_failed.close()
file_output.write("failed: "+str(host_name+"\n"))
file_output.close()
#quit()
except paramiko.ssh_exception.NoValidConnectionsError:
#print ("might be windows------------")
file_output.write("failed: " + str(host_name + "\n"))
file_output.close()
file_failed.write(str(host_name+"\n"))
file_failed.close()
#quit()
except socket.gaierror:
#print ("wrong hostname/dns************")
file_output.write("error: "+str(host_name+"\n"))
file_output.close()
file_error.write(str(host_name + "\n"))
file_error.close()
ssh.close()
def performer1():
while True:
hostname_value = q.get()
check_hostname(hostname_value,pw_sent)
q.task_done()
if __name__ == '__main__':
print ("This script checks all the hostnames in the input_file with your standard password and write the outputs in below files: \n1.file_output\n2.file_success \n3.file_failed \n4.file_error \n")
f = open('output_file', 'w')
f.write("-------Output of all hosts-------\n")
f.close()
f = open('success_file', 'w')
f.write("-------Success hosts-------\n")
f.close()
f = open('failed_file', 'w')
f.write("-------Failed hosts-------\n")
f.close()
f = open('error_file', 'w')
f.write("-------Hosts with error-------\n")
f.close()
with open("input_file") as f:
hostname1 = f.read().splitlines()
#Read the standard password from the user
pw_sent=getpass.getpass("Enter the Password:")
for i in hostname1:
q.put(i)
#print ("all the hostname : "+str(list(q.queue)))
for no_of_threads in range(3):
t = threading.Thread(target=performer1)
t.daemon=True
t.start()
q.join()
print ("Check output files for results")
print ("completed task in" + str(time.time()-start_time1) + "seconds")