edge-monitoring/agent_modem/edge_monitoring_agent_modem.py

#!/usr/bin/env python3

# Copyright 2020-present Open Networking Foundation
#
# SPDX-License-Identifier: LicenseRef-ONF-Member-Only-1.0

import sys
import os
import json
import logging
import enum
import requests
import time
import serial
import subprocess
from collections import namedtuple

'''
"Simple" script that checks Aether network operational status periodically
by controlling the attached 4G/LTE modem with AT commands and
report the result to the central monitoring server.
'''


CONF = json.loads(
    open(os.getenv('CONFIG_FILE', "./config.json")).read(),
    object_hook=lambda d: namedtuple('X', d.keys())(*d.values())
)

logging.basicConfig(
    filename=CONF.log_file,
    format='%(asctime)s [%(levelname)s] %(message)s',
    level=logging.getLevelName(CONF.log_level)
)


class State(enum.Enum):
    error = "-1"
    disconnected = "0"
    connected = "1"

    @classmethod
    def has_value(cls, value):
        return value in cls._value2member_map_


class Modem():
    log = logging.getLogger('aether_edge_monitoring.Modem')

    read_timeout = 0.1

    def __init__(self, port, baudrate):
        self.port = port
        self.baudrate = baudrate
        self._response = None

    def connect(self):
        self.serial = serial.Serial(
            port=self.port,
            baudrate=self.baudrate,
            timeout=1)

    def _write(self, command):
        if self.serial.inWaiting() > 0:
            self.serial.flushInput()

        self._response = b""

        self.serial.write(bytearray(command + "\r", "ascii"))
        read = self.serial.inWaiting()
        while True:
            if read > 0:
                self._response += self.serial.read(read)
            else:
                time.sleep(self.read_timeout)
            read = self.serial.inWaiting()
            if read == 0:
                break
        return self._response.decode("ascii").replace('\r\n', ' ')

    def write(self, command, wait_resp=True):
        response = self._write(command)
        self.log.debug("%s: %s", command, response)

        if wait_resp and "ERROR" in response:
            return False, None
        return True, response

    def get_state(self):
        success, result = self.write('AT+CGATT?')
        if not success or 'CGATT:' not in result:
            return State.error
        state = result.split('CGATT:')[1].split(' ')[0]
        return State(state)

    def close(self):
        self.serial.close()


def get_control_plane_state(modem):
    # Disable radio fuction
    # "echo" works more stable than serial for this action
    try:
        logging.debug("echo 'AT+CFUN=0' > " + CONF.modem.port)
        subprocess.check_output(
            "echo 'AT+CFUN=0' > " + CONF.modem.port, shell=True)
    except subprocess.CalledProcessError as e:
        logging.error("Write 'AT+CFUN=0' failed")
        return State.error

    # Wait until the modem is fully disconnected
    retry = 0
    state = None
    while retry < CONF.detach_timeout:
        state = modem.get_state()
        if state is State.disconnected:
            break
        time.sleep(1)
        retry += 1

    if state is not State.disconnected:
        logging.error("Failed to disconnect")
        return State.error

    time.sleep(2)
    # Enable radio function
    # "echo" works more stable than serial for this action
    try:
        logging.debug("echo 'AT+CFUN=1' > " + CONF.modem.port)
        subprocess.check_output(
            "echo 'AT+CFUN=1' > " + CONF.modem.port, shell=True)
    except subprocess.CalledProcessError as e:
        logging.error("Write 'AT+CFUN=1' failed")
        return State.error

    # Wait attach_timeout sec for the modem to be fully connected
    retry = 0
    while retry < CONF.attach_timeout:
        state = modem.get_state()
        if state is State.connected:
            break
        time.sleep(1)
        retry += 1
    # CGATT sometimes returns None
    if state is State.error:
        state = State.disconnected

    return state


def get_user_plane_state(modem):
    try:
        subprocess.check_output(
            "ping -c 3 " + CONF.ips.user_plane_ping_test + ">/dev/null 2>&1",
            shell=True)
        return State.connected
    except subprocess.CalledProcessError as e:
        logging.warning("User plane test failed")
        return State.disconnected


def run_ping_test(ip, count):
    '''
    Runs the ping test
    Input: IP to ping, # times to ping
    Returns: dict of the min/avg/max/stddev numbers from the ping command result
    '''
    result = {'min': 0.0,
              'avg': 0.0,
              'max': 0.0,
              'stddev': 0.0}
    try:
        pingResult = subprocess.check_output(
                "ping -c " + str(count) + " " + ip + \
                " | tail -1 | awk '{print $4}'",
                shell=True).decode("UTF-8").split("/")
        result = {'min': float(pingResult[0]),
                  'avg': float(pingResult[1]),
                  'max': float(pingResult[2]),
                  'stddev': float(pingResult[3])}
    except Exception as e:
        logging.error("Ping test failed for " + ip + ": %s", e)
    return result


def get_ping_test(modem):
    '''
    Each ping test result saves the min/avg/max/stddev to dict.
    1) Performs ping test to Google Public DNS for 10 iterations.
    2) # TODO: Performs ping to device on network.
    '''
    speedtest_ping = {}
    speedtest_ping['dns'] = run_ping_test(CONF.ips.speedtest_ping_dns, 10)
    return speedtest_ping


def get_signal_quality(modem):
    success, result = modem.write('AT+CESQ')
    if not success or 'CESQ: ' not in result:
        logging.error("Failed to get signal quality")
        return 0, 0

    logging.debug("%s", result)
    tmp_rsrq = result.split('CESQ:')[1].split(',')[4]
    tmp_rsrp = result.split('CESQ:')[1].split(',')[5]

    rsrq = int(tmp_rsrq.strip())
    rsrp = int(tmp_rsrp.strip().split(' ')[0])
    result = {
        'rsrq': 0 if rsrq is 255 else rsrq,
        'rsrp': 0 if rsrp is 255 else rsrp
    }

    return result


def report_status(signal_quality, cp_state=None, up_state=None, speedtest_ping=None):
    report = {
        'name': CONF.edge_name,
        'status': {
            'control_plane': "disconnected",
            'user_plane': "disconnected"
        },
        'speedtest': {
            'ping': {
                'dns': {
                    'min': 0.0,
                    'avg': 0.0,
                    'max': 0.0,
                    'stddev': 0.0
                }
            }
        },
        'signal_quality': {
            'rsrq': 0,
            'rsrp': 0
        }
    }

    if cp_state is not None:
        report['status']['control_plane'] = cp_state.name
    if up_state is not None:
        report['status']['user_plane'] = up_state.name
    if speedtest_ping is not None:
        report['speedtest']['ping'] = speedtest_ping
    report['signal_quality'] = signal_quality

    logging.info("Sending report %s", report)
    try:
        result = requests.post(CONF.report_url, json=report)
    except requests.exceptions.ConnectionError:
        logging.error("Failed to report for %s", e)
        pass
    try:
        result.raise_for_status()
    except requests.exceptions.HTTPError as e:
        logging.error("Failed to report for %s", e)
        pass
    time.sleep(CONF.report_interval)


def main():
    for ip in CONF.ips:
        try:
            subprocess.check_output("sudo ip route replace {}/32 via {}".format(
                ip, CONF.modem.ip_addr), shell=True)
        except subprocess.CalledProcessError as e:
            logging.error("Failed to add routes", e.returncode, e.output)
            sys.exit(1)

    modem = Modem(CONF.modem.port, CONF.modem.baud)
    try:
        modem.connect()
    except serial.serialutil.SerialException as e:
        logging.error("Failed to connect the modem for %s", e)
        sys.exit(1)

    while True:
        signal_quality = get_signal_quality(modem)

        cp_state = get_control_plane_state(modem)
        if cp_state is State.error:
            logging.error("Modem is in error state.")
            sys.exit(1)
        if cp_state is State.disconnected:
            # Failed to attach, don't need to run other tests
            report_status(signal_quality)
            continue

        up_state = get_user_plane_state(modem)
        if up_state is State.disconnected:
            # Basic user plan test failed, don't need to run the rest of tests
            report_status(signal_quality, cp_state)
            continue

        speedtest_ping = get_ping_test(modem)
        report_status(signal_quality, cp_state, up_state, speedtest_ping)

    modem.close()


if __name__ == "__main__":
    main()