Question on Ethernet connectivity robustness

[bcelary]

Hi,
I am wondering how robust is ArduinoHA in terms of Ethernet outages? My device is a button+relay board and it should be able to operate without issues when the Ethernet is disconnected and should be able to reconnect with the MQTT once the connection is restored. I still need to check if the Ethernet library will behave as expected but I wonder if such cases are handled by ArduinoHA?

What would happen if during boot-up there is no Ethernet link/MQTT server available? Would it work later when the connection is re-established?

Many thanks for this great piece of software BTW - saved me a great amount of work ❤️ !

[bcelary]

I think I was able to address some of the issues that arise if there is no connectivity on the board.

First of all - I see that indeed the connection is kept up and if it isn't connected initially, it will connect when possible.

But the connection attempts are adding quite a lot of overhead based on what I have observed, so in my specific case, I have added longer intervals between DHCP retries and the MQTT reconnections.

Here's roughly how this looks (declarations and defines missing but should be self explanatory):

void setup() {
    Ethernet.init(ETH_SCS_PIN);
    int rc = Ethernet.begin(mac, ETH_DHCP_TIMEOUT);
    if (rc) {
        maintainInt = ETH_DHCP_OK_MAINT_INT;
    }
    else {
        maintainInt = ETH_DHCP_NOK_MAINT_INT;
    }
    haDevice.setName("Arduino");
    haMqtt.begin(BROKER_ADDR, BROKER_USER, BROKER_PASS);
    // haMqtt initial loop to check for MQTT connection
    haMqtt.loop();
}

inline void haMqttLoop() {
    if (haMqtt.isConnected()) {
        haMqtt.loop();
    }
    else {
        if (currentTime - mqttRetryLast > BROKER_RETRY_INT) {
            mqttRetryLast = currentTime;
            haMqtt.loop();
        }
    }
}


inline void ethernetMaintain() {
    if (currentTime - maintainLast > maintainInt) {
        maintainLast = currentTime;

        int rc = Ethernet.maintain();
        IPAddress ip = Ethernet.localIP();

        if (dhcpMaintainFail(rc) || allZerosIp(ip)) {
            maintainInt = ETH_DHCP_NOK_MAINT_INT;
        }
        else {
            maintainInt = ETH_DHCP_OK_MAINT_INT;
        }
    }
}

inline bool allZerosIp(const IPAddress &ip) {
    return (ip[0] == 0 && ip[1] == 0 && ip[2] == 0 && ip[3] == 0);
}

inline bool dhcpMaintainFail(int rc) {
    return (rc == 1 || rc == 3);
}