run command with paramiko for a certain amount of time

Question

I am using the Paramiko module in Python to ssh into another machine and execute a command.

The command invokes a program that produces output continuously. My goal would be to run something like this:

stdin, stdout, stderr = ssh.exec_command(mycommand)  

with the additional constraint that after X seconds "my command" is terminated, just like pressing Ctrl + C and return the output to stdout.

Is there a way (or an alternative way) to do it?

Answer 1

If the remote host is running Unix, you can pass a shell script to do this as mycommand:

stdin, stdout, stderr = client.exec_command(
    """
    # simple command that prints nonstop output; & runs it in background
    python -c '
import sys
import time

while 1:
  print time.time()
  sys.stdout.flush()
  time.sleep(0.1)
    ' &
    KILLPID=$!; # save PID of background process
    sleep 2; # or however many seconds you'd like to sleep
    kill $KILLPID
    """)

When run, this prints the current time at 100ms intervals for 2 seconds:

... 1388989588.39
... 1388989588.49
... 1388989588.59
... 1388989588.69
... 1388989588.79
... 1388989588.89
... 1388989588.99
... 1388989589.1
... 1388989589.2
... 1388989589.3
... 1388989589.4
... 1388989589.5
... 1388989589.6
... 1388989589.71
... 1388989589.81
... 1388989589.91
... 1388989590.01
... 1388989590.11
... 1388989590.21
... 1388989590.32

and then gracefully stops.