How to reconnect to the opc server when we lost connection with the opc server ?

[argiraud]

Hi,
I'm trying to test if my app reconnect to the opc server when I plug out my app from the network and plug in after 10 seconde. It appears that subscriptions can't be re-create unless I re-run my app. I'm in version 0.6.1.
I saw that normally the re-connection is automatic.
I don't know what I do wrong.

[kevinherron]

All you need to do is add a SubscriptionListener to the OpcUaSubscriptionManager and implement SubscriptionListener::onSubscriptionTransferFailed. Any time this is called it means the client has reconnected but was unable to resume the session or transfer the old subscription, so you have to re-create it.

[argiraud]

Thanks for your reactivity! You were really helpful and it resolve my problem.

[argiraud]

I'm having issues when my opc-client trying to resubscribe to the Matrikon OPC server. When I lose the connection and try to reconnect subscription with onSubscriptionTransferFailed the Matrikon OPC server is going too busy so it refused to resubscribe. Do I have to wait a little amount of time each time I am trying to recreate subscription in my code ?

[kevinherron]

That's not something I've seen before. What kind of error do you get when you create your subscriptions again?

[argiraud]

10:59:39.129 [milo-shared-thread-pool-12] ERROR c.a.o.l.SessionListenerHandlingSubscription.onSessionInactive(32) - Session inactive for opc.tcp://XXX/MatrikonOpcUaWrapper

10:59:40.670 [milo-shared-thread-pool-13] ERROR c.a.o.listener.SubscriptionListener.onSubscriptionTransferFailed(48) - onSubscriptionTransferFailed for opc.tcp://XXX/MatrikonOpcUaWrapper subscription 35 status: StatusCode{n
ame=Bad_ServiceUnsupported, value=0x800B0000, quality=bad} try to force resubscription

10:59:41.200 [milo-shared-thread-pool-12] INFO c.a.o.l.SessionListenerHandlingSubscription.onSessionActive(21) - Session active for opc.tcp://XXX/MatrikonOpcUaWrapper

10:59:41.805 [milo-shared-thread-pool-12] ERROR c.a.o.l.SessionListenerHandlingSubscription.onSessionInactive(32) - Session inactive for opc.tcp://XXX/MatrikonOpcUaWrapper

Again and again
Sometimes it go back to normal, sometimes not and after a certain moment it stops trying to reconnect.
When my opc-client is doing that I can't connect to OPC server with an another opc client like UAExpert and when I stop my opc client UAExpert can connect to the server.

In Matrikon server there are serverTooBusy errors.

The only solution I found is to restart my opc client but it doesn't work all the time.

[kevinherron]

What does your re-subscribe logic/code look like? I guess maybe Matrikon can't handle very much and you might need to build a little delay into the logic. Are there a lot of subscriptions or monitored items you're making?

…

On Thu, Sep 23, 2021 at 7:50 AM argiraud ***@***.***> wrote: `10:59:39.129 [milo-shared-thread-pool-12] ERROR c.a.o.l.SessionListenerHandlingSubscription.onSessionInactive(32) - Session inactive for opc.tcp://XXX/MatrikonOpcUaWrapper 10:59:40.670 [milo-shared-thread-pool-13] ERROR c.a.o.listener.SubscriptionListener.onSubscriptionTransferFailed(48) - onSubscriptionTransferFailed for opc.tcp://XXX/MatrikonOpcUaWrapper subscription 35 status: StatusCode{n ame=Bad_ServiceUnsupported, value=0x800B0000, quality=bad} try to force resubscription 10:59:41.200 [milo-shared-thread-pool-12] INFO c.a.o.l.SessionListenerHandlingSubscription.onSessionActive(21) - Session active for opc.tcp://XXX/MatrikonOpcUaWrapper 10:59:41.805 [milo-shared-thread-pool-12] ERROR c.a.o.l.SessionListenerHandlingSubscription.onSessionInactive(32) - Session inactive for opc.tcp://XXX/MatrikonOpcUaWrapper ` Again and again Sometimes it go back to normal, sometimes not and after a certain moment it stops trying to reconnect. When my opc-client is doing that I can't connect to OPC server with an another opc client like UAExpert and when I stop my opc client UAExpert can connect to the server. In Matrikon server there are serverTooBusy errors. The only solution I found is to restart my opc client but it doesn't work all the time. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#833 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACTCMM6ADB5AGVEXM5RNXLUDM5BXANCNFSM433SLV7A> .

[argiraud]

public void forceResuscribeOnReconnection() throws Exception {
        if (!tagSubscribes.isEmpty()) {
            opcUaClient.getSubscriptionManager().clearSubscriptions();
            List<TagConfiguration> oldSubscriptions = new ArrayList<>(tagSubscribes);
            tagSubscribes.clear();
            subscribe(oldSubscriptions, this.valueConsumer);
        }
    }
public void subscribe(List<TagConfiguration> tags, BiConsumer<TagConfiguration, TagValue> valueConsumer) throws ExecutionException, InterruptedException {
        this.valueConsumer = valueConsumer;
        UaSubscription subscription = opcUaClient.getSubscriptionManager().createSubscription(this.requestedPublishInterval).get();
        List<MonitoredItemCreateRequest> requests = createMonitoredItemCreateRequest(tags);
        createMonitoredItems(tags, subscription, requests);
    }

Maybe you right i should build a little delay. There are like one hundred monitored items.

[kevinherron]

You don't need that call to clearSubscriptions. If transfer fails the subscription manager cleans up its own bookkeeping.

You will get one callback per failed subscription transfer, so only re-create that particular subscription when it happens, don't just clear everything and re-create everything.

[argiraud]

Yes you are right.
I have only one subscription for all my items. So I have to recreate only the monitored items not working ?

[kevinherron]

You'll have to re-create the subscription and all its monitored items. I'm just looking at your logic and if you ever had multiple subscriptions you would need to make the changes I suggested. If multiple subscriptions are in use, and the server doesn't support transfers, then you'll get a callback for each of them. If in each callback you tried to clear and re-create *all* subscriptions you should be able to see why that would lead to issues.

…

On Thu, Sep 23, 2021 at 8:45 AM argiraud ***@***.***> wrote: Yes you are right. I have only one subscription for all my items. So I have to recreate only the monitored items not working ? — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#833 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACTCMJGNFAXNKCRBWWIE3LUDNDPZANCNFSM433SLV7A> .

[argiraud]

I will make the changes and look in my logic to see why I send too many things to Matrikon.
Thanks again for your help !

[kevinherron]

I’m going to be away from internet and cell service for a few days. If you get stuck then getting a Wireshark capture of this reconnect dynamic with security disabled might help me see what’s going on better when I’m back.

…

On Sep 23, 2021, at 09:08, argiraud ***@***.***> wrote:  I will make the changes and look in my logic to see why I send too many things to Matrikon. Thanks again for your help ! — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub, or unsubscribe.

[argiraud]

Thanks I will do it