CODEWITHSUNDEEP
pythonssh
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Reputation: 11

Paramiko with continuous stdout while running remote python script

I'm trying to run a remote Python script using Paramiko and have it forward anything Python prints back to the client in realtime (i.e. continuous stdout). I connect to my server by calling my class with the following:

class SSH:
    client = None

    def __init__(self, address, username, password):
        self.client = client.SSHClient()
        self.client.set_missing_host_key_policy(client.AutoAddPolicy())
        self.client.connect(address, username=username, password=password, look_for_keys=False)

I then send commands to the server through my send_command function:

def send_command(self, command):
    if(self.client):
        stdin, stdout, stderr = self.client.exec_command(command)
        for i in range(5): # just print 5 bytes
            print(stdout.channel.recv(1))
            time.sleep(0.1)
    else:
        print("Connection not opened.")

Normally, this would work with any continuous/looping command that fills the buffer on stdout as it loops. My problem is that for some reason stdout is filled only when the Python script finishes running, and anything that Python would output comes up only AFTER the script finishes. I want it to print while the script is running. This is the test script I'm using:

from time import sleep
print("Test.")
sleep(1)
print("Test again.")
sleep(2)
print("Final test.")

Is there a way around this or am I doing anything wrong? Thanks in advance.

Upvotes: 0

Views: 1225

Answers (1)

LUX
LUX

Reputation: 11

Problem solved. The solution was actually very simple. I had to request a psuedo-terminal from the server when running a Python script (command = 'python3.6 test.py'). This is done in Paramiko by simply setting the get_pty bool flag to True. See below (note the get_pty in exec_command):

class SSH:
    client = None

    def __init__(self, address, username, password):
        self.client = client.SSHClient()
        self.client.set_missing_host_key_policy(client.AutoAddPolicy())
        self.client.connect(address, username=username, password=password, look_for_keys=False)

    def send_command(self, command):
        if(self.client):
            stdin, stdout, stderr = self.client.exec_command(command, get_pty=True)
            while not stdout.channel.exit_status_ready():
                OUT = stdout.channel.recv(1024)
                print(OUT)
        else:
            print("Connection not opened.")

I'm now successfully continuously printing the output of the Python script in real-time.

Upvotes: 1

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