python subprocess uds notes

README.md

in one terminal:

python processor.py

in another terminal:

nc -U /tmp/my_unix_socket

and in the nc window, type asdf and press enter

dispatcher.py

import socket
import subprocess
import os
import time

# Define the path for the Unix domain socket
SOCKET_PATH = "/tmp/unix_domain_socket_example"

# Ensure the socket doesn't already exist
if os.path.exists(SOCKET_PATH):
    os.unlink(SOCKET_PATH)

# Function to start a subprocess that listens on the Unix domain socket
def start_subprocess():
    # Start a subprocess that listens on the Unix socket
    return subprocess.Popen(
        ['sh', '-c', f"""
        while true; do
            if [ -S "{SOCKET_PATH}" ]; then
                nc -lU "{SOCKET_PATH}" | while read line; do
                    echo "Received: $line"
                    sleep 1
                done
            fi
        done
        """],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE
    )

# Create a Unix domain socket
server_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
server_socket.bind(SOCKET_PATH)
server_socket.listen(1)

# Start the subprocess
subprocess_listener = start_subprocess()
print("Subprocess started and listening on the Unix domain socket...")

# Connect to the Unix domain socket as a client
client_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
client_socket.connect(SOCKET_PATH)

print("")
# Send a request to the subprocess through the socket
client_socket.sendall(b"Hello from the client\n")

# Receive streaming output from the subprocess
def receive_stream():
    while True:
        output = subprocess_listener.stdout.readline()
        if output == b"" and subprocess_listener.poll() is not None:
            break
        if output:
            print(f"Subprocess output: {output.decode().strip()}")

# Start receiving the stream output
try:
    receive_stream()
finally:
    # Cleanup
    client_socket.close()
    server_socket.close()
    subprocess_listener.terminate()
    os.unlink(SOCKET_PATH)
    print("Sockets closed and subprocess terminated.")

processor.py

import socket
import os

# Specify the path for the Unix domain socket
SOCKET_PATH = "/tmp/my_unix_socket"

# Ensure the socket path doesn't already exist
if os.path.exists(SOCKET_PATH):
    os.unlink(SOCKET_PATH)

# Create a Unix domain socket
server_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)

# Bind the socket to the specified path
server_socket.bind(SOCKET_PATH)

# Start listening for incoming connections
server_socket.listen(1)
print(f"Listening on {SOCKET_PATH}")

try:
    # Wait for a client to connect
    connection, client_address = server_socket.accept()
    print("Client connected")

    # Stream data back to the client
    with connection:
        while True:
            # Receive data from the client
            data = connection.recv(1024)
            if not data:
                break
            print(f"Received: {data.decode().strip()}")

            # Process data and send a response back to the client
            response = f"Echoing back: {data.decode().strip()}\n"
            connection.sendall(response.encode())
            print(f"Sent: {response.strip()}")

finally:
    # Cleanup
    server_socket.close()
    os.unlink(SOCKET_PATH)
    print("Socket closed and cleaned up.")