Running interactive commands in Paramiko

Question

I'm trying to run an interactive command through paramiko. The cmd execution tries to prompt for a password but I do not know how to supply the password through paramiko's exec_command and the execution hangs. Is there a way to send values to the terminal if a cmd execution expects input interactively?

ssh = paramiko.SSHClient()
ssh.connect(server, username=username, password=password)
ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command("psql -U factory -d factory -f /tmp/data.sql")

Does anyone know how this can addressed? Thank you.

• Mino_e: The question is old but for the people who still come here via google search i want to give them this.The key is to get your own channel Executing Interactive Commands in Python through Paramiko Part 1 Executing Interactive Commands in Python through Paramiko Part 2 In this two videos it's explained how to run interactive commands via paramiko especially the second video is great and probably what you need.

Answer 1

The full paramiko distribution ships with a lot of good demos.

In the demos subdirectory, demo.py and interactive.py have full interactive TTY examples which would probably be overkill for your situation.

In your example above ssh_stdin acts like a standard Python file object, so ssh_stdin.write should work so long as the channel is still open.

I've never needed to write to stdin, but the docs suggest that a channel is closed as soon as a command exits, so using the standard stdin.write method to send a password up probably won't work. There are lower level paramiko commands on the channel itself that give you more control - see how the SSHClient.exec_command method is implemented for all the gory details.

• Paul Hoffman: And, for those of you who got here wanting to only see what the output of a command might be, some code might be: (stdin, stdout, stderr) = Client.exec_command('ls -la') print("\nstdout is:\n" + stdout.read() + "\nstderr is:\n" + stderr.read())
• scy won't contribute anymore: Fixed broken link.

Answer 2

I had the same problem trying to make an interactive ssh session using ssh, a fork of Paramiko.

I dug around and found this article:

Updated link (last version before the link generated a 404): http://web.archive.org/web/20170912043432/http://jessenoller.com/2009/02/05/ssh-programming-with-paramiko-completely-different/

To continue your example you could do

ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command("psql -U factory -d factory -f /tmp/data.sql")
ssh_stdin.write('password\n')
ssh_stdin.flush()
output = ssh_stdout.read()

The article goes more in depth, describing a fully interactive shell around exec_command. I found this a lot easier to use than the examples in the source.

Original link: http://jessenoller.com/2009/02/05/ssh-programming-with-paramiko-completely-different/

• Tushar Vazirani: The link is broken :(

Answer 3

You need Pexpect to get the best of both worlds (expect and ssh wrappers).

• JerodG: I would recommend this as well. Here is an example that controls multiple servers at the same time but it could easily be used on just one. github.com/pexpect/pexpect/blob/master/examples/hive.py

Answer 4

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(server_IP,22,username, password)
stdin, stdout, stderr = ssh.exec_command('/Users/lteue/Downloads/uecontrol-CXC_173_6456-R32A01/uecontrol.sh -host localhost ')
alldata = ""
while not stdout.channel.exit_status_ready():
 solo_line = "" 
 # Print stdout data when available
 if stdout.channel.recv_ready():
 # Retrieve the first 1024 bytes
 solo_line = stdout.channel.recv(1024) 
 alldata += solo_line
 if(cmp(solo_line,'uec> ') ==0 ): #Change Conditionals to your code here 
 if num_of_input == 0 :
 data_buffer = "" 
 for cmd in commandList :
 #print cmd
 stdin.channel.send(cmd) # send input commmand 1
 num_of_input += 1
 if num_of_input == 1 :
 stdin.channel.send('q \n') # send input commmand 2 , in my code is exit the interactive session, the connect will close.
 num_of_input += 1 
print alldata
ssh.close() 

Why the stdout.read() will hang if use dierectly without checking stdout.channel.recv_ready(): in while stdout.channel.exit_status_ready():

For my case ,after run command on remote server , the session is waiting for user input , after input 'q' ,it will close the connection . But before inputting 'q' , the stdout.read() will waiting for EOF,seems this methord does not works if buffer is larger .

• I tried stdout.read(1) in while , it works
  I tried stdout.readline() in while , it works also.
  stdin, stdout, stderr = ssh.exec_command('/Users/lteue/Downloads/uecontrol')
  stdout.read() will hang

• Sharmila: This should be made a separate question if you need an answer (as this is an old question). Or atleast it should be a comment on the question or one of the answers. It cannot be an answer by itself.
• Janne Paalijarvi: Excellent answer which helped me forward. For who it might interest: I had problem reading the last line I needed from the command in a multi-threaded application. Stuff just seemed to hang. But then I started issuing ssh_stdout.channel.close() and then doing final read with ssh_stdout.channel.recv(1000) . Boom, no more hangs! (Of course everyone should consider if this method is applicable to their code.)

Answer 5

I'm not familiar with paramiko, but this may work:

ssh_stdin.write('input value')
ssh_stdin.flush()

For information on stdin:

http://docs.python.org/library/sys.html?highlight=stdin#sys.stdin

• aculich: NOTE: Always make sure to flush() any buffer you're writing to the way this example correctly shows; forgetting (or not knowing) to do this is a common cause for frustration.

Answer 6

Take a look at example and do in similar way

(sorce from http://jessenoller.com/2009/02/05/ssh-programming-with-paramiko-completely-different/):

 ssh.connect('127.0.0.1', username='jesse', 
 password='lol')
 stdin, stdout, stderr = ssh.exec_command(
 "sudo dmesg")
 stdin.write('lol\n')
 stdin.flush()
 data = stdout.read.splitlines()
 for line in data:
 if line.split(':')[0] == 'AirPort':
 print line

• Paula Livingstone: Source link broken

Answer 7

You can use this method to send whatever confirmation message you want like "OK" or the password. This is my solution with an example:

def SpecialConfirmation(command, message, reply):
 net_connect.config_mode() # To enter config mode
 net_connect.remote_conn.sendall(str(command)+'\n' )
 time.sleep(3)
 output = net_connect.remote_conn.recv(65535).decode('utf-8')
 ReplyAppend=''
 if str(message) in output:
 for i in range(0,(len(reply))):
 ReplyAppend+=str(reply[i])+'\n'
 net_connect.remote_conn.sendall(ReplyAppend)
 output = net_connect.remote_conn.recv(65535).decode('utf-8') 
 print (output)
 return output
CryptoPkiEnroll=['','','no','no','yes']
output=SpecialConfirmation ('crypto pki enroll TCA','Password' , CryptoPkiEnroll )
print (output)