Why is the connection to the server not being restored after a long break?

Question

Python

On the remote raspbury, the code that collects and transmits data to the server is spinning. When the connection is broken, there is an endless reconnection, but if there was no connection for a very long time, for example, about a day, then the reconnection procedure is blocked somewhere or hangs. It's hard to understand what exactly happened. I connect via SSH, I see the code running, I see how it collects data, but I don't see any attempts to connect to the server. (data collection and sending work in different threads). If the gap was not long - a couple of hours, let's say, then there is no problem.

def connectToServer ():
    print("Server: connecting")
    global ServerSock
    try:
        ServerSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        ServerSock.settimeout(10)
        ServerSock.connect((ServerHost, ServerPort))
        ServerSock.settimeout(10)
        print("Server: connected")
    except:
        print("error occured")
        ServerSock.close()
        time.sleep(5)
        connectToServer()



def runServerSending ():
    connectToServer()
    while True:
            try:
                ServerSock.sendall(json.dumps(this.__dict__).encode())
                answer = ServerSock.recv(1024)
                if not answer:
                    raise Exception('Server socket error')
            except:
                print("Server: send data error")
                ServerSock.close()
                connectToServer()
            time.sleep(10)

Answer 1

Perhaps you have a buffer overflow due to a recurrent call to connectToServer ()

def connectToServer ():
    ....
    except:
        print("error occured")
        ServerSock.close()
        time.sleep(5)
        connectToServer()

Try like this:

def connectToServer ():
    print("Server: connecting")
    global ServerSock
    connected = False
    while not connected:
        try:
            ServerSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            ServerSock.settimeout(10)
            ServerSock.connect((ServerHost, ServerPort))
            ServerSock.settimeout(10)
            print("Server: connected")
            connected = True
        except:
            print("error occured")
            ServerSock.close()
            time.sleep(5)