Websocket conection closes abnormally

[Joshua_Omolo]

I adapted a snippet of code to send commands between my controller (Raspberry Pi) to a remote server using the OCPP 1.6 protocol.

The script initializes connection, sends a heartbeat to the server but problem is that this connection drops unexpectedly after about 1-2 hours. Is there anything I can do to ensure that the connection stays open indefinitely?

Herewith is the code:

import asyncio
import websockets
import RPi.GPIO as GPIO
import time

from ocpp.v16 import call, ChargePoint as cp
from ocpp.v16.enums import RegistrationStatus
#from gpiozero import Button
#PB_port_1 = Button(23) #left push button on charger
#PB_port_2 = Button(24) #right push button on charger

GPIO.setmode (GPIO.BCM)
GPIO.setup(23,GPIO.IN,pull_up_down=GPIO.PUD_UP)
GPIO.add_event_detect(23,GPIO.RISING, bouncetime= 1000)

class ChargePoint(cp):
    async def send_boot_notification(self):
        request = call.BootNotificationPayload(
            charge_point_model="DUAL PORT AC",
            charge_point_vendor="MENNEKES"
        )
        response = await self.call(request)

        if response.status ==  RegistrationStatus.accepted:

            print("Connected to EV back office.")
            print("Heartbeat: " + str(response.interval))
            print("Heartbeat: " + str(response.current_time))

    async def runner(self):
        while True:
            if GPIO.event_detected(23):
                print("Button 23 pressed")

# secondary loop to manage the operations of the charge station
    async def running_state(self):

        keep_running = True
        while keep_running:

            if PB_port_1.is_pressed or PB_port_2.is_pressed:
            #logic inverted; when PB is released on charger
                print("Push Button released")
                await self.Send_StatusNotification_available()
                break
            else:
            #logic inverted; when PB is pressed on charger
                print("Push Button pressed")
                await self.Send_StatusNotification_unavailable()
                break


    async def Heartbeat(self):
        while True:
            request = call.HeartbeatPayload()
            response = await self.call(request)
            #("Heartbeat: " + str(response.current_time))
            time.sleep(60)

# charge cable connected, no fault - status change to available
    async def Send_StatusNotification_available(self):
        request = call.StatusNotificationPayload(
            connector_id = 0,
            error_code = "NoError",
            status = "Available"
        )
        response = await self.call(request)

        print ("Charge Point Available")

# charge cable connected - status change to unavailable
    async def Send_StatusNotification_unavailable(self):
        request = call.StatusNotificationPayload(
            connector_id = 0,
            error_code = "NoError",
            status = "Unavailable"
        )
        response = await self.call(request)
        print("Charge Point Occupied")

# charge cable connected, fault - status change to fault
    async def Send_StatusNotification_fault(self):
        request = call.StatusNotificationPayload(
            connector_id = 0,
            error_code = "InternalError",
            status = "Faulted"
        )
        response = await self.call(request)
        print("Charger Internal Error")
#--------------------------------------------

async def main():
    async with websockets.connect(
       'wss://data.evbackoffice.com/json/SA-EVB-MEN0003',
         subprotocols=['ocpp1.6'],
         ping_interval = None
    ) as ws:

        cp = ChargePoint('SA-EVB-MEN0003', ws)

        await asyncio.gather(cp.start(),cp.send_boot_notification(),cp.Heartbeat())

        while True:
            if not ws.open:
                try:
                    print('Websocket not connected...reconnecting')
                    async with websockets.connect(
                        'wss://data.evbackoffice.com/json/SA-EVB-MEN0003',
                        subprotocols=['ocpp1.6'],
                        ping_interval = None
                    ) as ws:

                        cp = ChargePoint('SA-EVB-MEN0003', ws)

                        await asyncio.gather(cp.start(),cp.send_boot_notification(),cp.Heartbeat())

                except:
                    print('Unable to connect')

if __name__ == '__main__':
    asyncio.run(main())

Larz60+ write Feb-12-2021, 09:20 PM:
Please post all code, output and errors (it it's entirety) between their respective tags. Refer to BBCode help topic on how to post. Use the "Preview Post" button to make sure the code is presented as you expect before hitting the "Post Reply/Thread" button.

Fixed for you this time. Please use bbcode tags on future posts.

[nilamo]

The internet is unpredictable. Aside from things timing out, devices sometimes lose connection to the internet, which breaks any sockets they had open. That might not be the issue here, but the point is that expecting a socket to remain open and available indefinitely is a goal that cannot be solved.

Is your while True loop not working? That would be the recommended way (well, possibly with an exponential backoff) to handle automatic reconnections.

[Joshua_Omolo]

The programme does not get into the while True loop when the connection drops. I am looking into how to ensure that it enters the loop. So far, I figured that the websocket must be closed correctly first before I can initialise it in the while True loop.