tcpspcket.py

import socket
import sys
import os
import subprocess
import time

RECHECK_INTERVAL_SECONDS = 10

# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_name = "0.0.0.0"  # Modify this if you want to bind only on a specific IP Address
server_address = (server_name, int(os.environ["TCP_HEALTH_CHECK_PORT"]))
print("starting up on %s port %s" % server_address, file=sys.stdout)
sock.bind(server_address)
sock.listen(1)

while True:

    # If RADIUS service is not available, then let health check fail by not listening for 10 seconds
    child = subprocess.Popen(
        [
            "eapol_test",
            "-a",
            os.environ["RADIUS_SERVER_IP"],
            "-p",
            "1812",  # 1812 is the standard RADIUS port
            "-A",
            os.environ["TEST_ROUTER_IP"],
            "-s",
            os.environ["TEST_ROUTER_SECRET"],
            "-c",
            "ttls-eap.conf",
            "-r0",
        ],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
    )
    (output, err) = child.communicate()

    # Meanwhile checkback the health status after 10 seconds to see if RADIUS server recovered back
    # If the service was not able to recover even on the successive tries:
    # * Then consecutive health checks will fail
    # * Current instance will be de-registered and drained
    if child.returncode != 0:
        time.sleep(RECHECK_INTERVAL_SECONDS)
        continue

    print("waiting for a connection", file=sys.stdout)
    connection, client_address = sock.accept()
    try:
        print("client connected:", client_address, file=sys.stdout)
        data = bytes("Server Alive", "utf-8")
        connection.sendall(data)
        connection.close()

    finally:
        connection.close()