I need to run a command on a remote host from a Python 3 script. I have tried several methods, but I cannot get any of them working. I tried using paramiko but pip fails when attempting to load the bcrypt module from the cryptography library. Apparently there is a missing equals sign according to the Python exception when running pip3 install paramiko.
I tried using pxssh from pexpect, but it raises an exception when I try to login saying it cannot establish a connection to the host. It does this whether I try the remote host or localhost
#! /usr/bin/python3
from pexpect import pxssh
ssh = pxssh.pxssh()
if not ssh.login("192.168.1.34", "xxxxxxx", "yyyyyyyy"):
print("Failed")
I tried the following code:
#! /usr/bin/python3
import time, subprocess, sys
IP = "192.168.1.34"
with open ("/var/run/thermostat/insideT", "r") as infile:
Temp = float(infile.read()) # Get inside temperature
if Temp > 75:
TString = IP + '"/usr/bin/gpio write 0 1"\n
subprocess.run(["ssh", TString])
But I get an error from ssh saying it cannot resolve the hostname 192.168.1.34. I have tried several different variations on the subprocess call.
ssh: Could not resolve hostname 192.168.1.34 : Name or service not known
ssh 192.168.1.34 "gpio write 0 1" works just fine.
Another way to handle this would be to read the value of the /var/run/thermostat/insideT on the local system from the remote system if that would be easier. I can run the script from either system.
Both hosts are Raspberry Pi systems running a recent version of Raspberry Pi OS. Note I have a passwordless login enabled for ssh between the systems.
I finally got it to work by eliminating some of the white space like this:
subprocess.run(["ssh", IP, "/usr/bin/gpio", "write 0 1"])
I still do not quite understand why ssh was complaining, rather than bash.