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javaopc-uamilo

Eclipse milo: Session closed when trying to read data

I have an external OPC UA server, from which I would like to read data. I use username and password authentication, so my client is initialized like follows:

public class MyClient {

    // ...

    public MyClient() throws Exception {
        EndpointDescription[] endpoints =
            UaTcpStackClient.getEndpoints(OPCConstants.OPC_SERVER_URI).get();

        // using the first endpoint
        EndpointDescription endpoint = endpoints[0];

        // client configuration
        OpcUaClientConfig config = OpcUaClientConfig.builder()
            .setApplicationName(LocalizedText.english("Example Client"))
            .setApplicationUri(String.format("some:example-client:%s",
                    UUID.randomUUID()))
            .setIdentityProvider(new UsernameProvider(USERNAME, PWD))
            .setEndpoint(endpoint)
            .build();
    }
}

The client's request is the following:

public CompletableFuture<DataValue> getData(NodeId nodeId) {
    LOGGER.debug("Sending request");
    return client.readValue(60000000.0, TimestampsToReturn.Server, nodeId);
}

I call this request from the main method after initializing the client and connecting it to the server:

MyClient client = new MyClient();

NodeId requestedData = new NodeId(DATA_ID, DATA_KEY);
LOGGER.info("Sending synchronous TestStackRequest NodeId={}",
       requestedData);
client.connect();
DataValue response = client.getData(requestedData).get();
LOGGER.info("Received response value={}", response.getValue());
client.disconnect();

However, this code doesn't work (the session is closed when trying to read informations from the server). I get the following output:

2018-04-12 17:43:27,765 DEBUG --- [ua-netty-event-loop-0] Recycler : -Dio.netty.recycler.maxCapacity.default: 262144
2018-04-12 17:43:27,777 DEBUG --- [ua-netty-event-loop-0] UaTcpClientAcknowledgeHandler : Sent Hello message on channel=[id: 0xfd9519e3, L:/172.20.100.54:55805 - R:/172.20.100.135:4840].
2018-04-12 17:43:27,786 DEBUG --- [ua-netty-event-loop-0] UaTcpClientAcknowledgeHandler : Received Acknowledge message on channel=[id: 0xfd9519e3, L:/172.20.100.54:55805 - R:/172.20.100.135:4840].
2018-04-12 17:43:27,793 DEBUG --- [ua-netty-event-loop-0] UaTcpClientMessageHandler : OpenSecureChannel timeout scheduled for +5s
2018-04-12 17:43:27,946 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : Sent OpenSecureChannelRequest (Issue, id=0, currentToken=-1, previousToken=-1).
2018-04-12 17:43:27,951 DEBUG --- [ua-netty-event-loop-0] UaTcpClientMessageHandler : OpenSecureChannel timeout canceled
2018-04-12 17:43:27,961 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : Received OpenSecureChannelResponse.
2018-04-12 17:43:27,967 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : SecureChannel id=1698234671, currentTokenId=1, previousTokenId=-1, lifetime=3600000ms, createdAt=DateTime{utcTime=131680285857690000, javaDate=Thu Apr 12 19:43:05 CEST 2018}
2018-04-12 17:43:27,968 DEBUG --- [ua-netty-event-loop-0] UaTcpClientMessageHandler : 0 message(s) queued before handshake completed; sending now.
2018-04-12 17:43:27,968 DEBUG --- [ua-shared-pool-1] ClientChannelManager : Channel bootstrap succeeded: localAddress=/172.20.100.54:55805, remoteAddress=/172.20.100.135:4840
2018-04-12 17:43:27,996 DEBUG --- [ua-shared-pool-0] ClientChannelManager : disconnect(), currentState=Connected
2018-04-12 17:43:27,997 DEBUG --- [ua-shared-pool-1] ClientChannelManager : Sending CloseSecureChannelRequest...
2018-04-12 17:43:28,000 DEBUG --- [ua-netty-event-loop-0] ClientChannelManager : channelInactive(), disconnect complete
2018-04-12 17:43:28,001 DEBUG --- [ua-netty-event-loop-0] ClientChannelManager : disconnect complete, state set to Idle
2018-04-12 17:43:28,011 INFO --- [main] OpcUaClient : Eclipse Milo OPC UA Stack version: 0.2.1
2018-04-12 17:43:28,011 INFO --- [main] OpcUaClient : Eclipse Milo OPC UA Client SDK version: 0.2.1
2018-04-12 17:43:28,056 DEBUG --- [main] OpcUaClient : Added ServiceFaultListener: org.eclipse.milo.opcua.sdk.client.session.SessionFsm$FaultListener@46d59067
2018-04-12 17:43:28,066 DEBUG --- [main] OpcUaClient : Added SessionActivityListener: org.eclipse.milo.opcua.sdk.client.subscriptions.OpcUaSubscriptionManager$1@78452606
2018-04-12 17:43:28,189 INFO --- [main] CommunicationMain : Sending synchronous TestStackRequest NodeId=NodeId{ns=6, id=::opcua:opcData.outGoing.basic.cycleStep}
2018-04-12 17:43:28,189 DEBUG --- [main] ClientChannelManager : connect(), currentState=NotConnected
2018-04-12 17:43:28,190 DEBUG --- [main] ClientChannelManager : connect() while NotConnected
java.lang.Exception
at org.eclipse.milo.opcua.stack.client.ClientChannelManager.connect(ClientChannelManager.java:67)
at org.eclipse.milo.opcua.stack.client.UaTcpStackClient.connect(UaTcpStackClient.java:127)
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.connect(OpcUaClient.java:313)
at com.mycompany.opcua.participants.MyClient.connect(MyClient.java:147)
at com.mycompany.opcua.participants.CommunicationMain.testClient(CommunicationMain.java:69)
at com.mycompany.opcua.participants.CommunicationMain.main(CommunicationMain.java:51)
2018-04-12 17:43:28,190 DEBUG --- [main] MyClient : Sending request
2018-04-12 17:43:28,197 DEBUG --- [ua-netty-event-loop-1] UaTcpClientAcknowledgeHandler : Sent Hello message on channel=[id: 0xd9b3f832, L:/172.20.100.54:55806 - R:/172.20.100.135:4840].
2018-04-12 17:43:28,204 DEBUG --- [ua-netty-event-loop-1] UaTcpClientAcknowledgeHandler : Received Acknowledge message on channel=[id: 0xd9b3f832, L:/172.20.100.54:55806 - R:/172.20.100.135:4840].
2018-04-12 17:43:28,205 DEBUG --- [ua-netty-event-loop-1] UaTcpClientMessageHandler : OpenSecureChannel timeout scheduled for +5s
2018-04-12 17:43:28,205 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : Sent OpenSecureChannelRequest (Issue, id=0, currentToken=-1, previousToken=-1).
2018-04-12 17:43:28,208 DEBUG --- [ua-netty-event-loop-1] UaTcpClientMessageHandler : OpenSecureChannel timeout canceled
2018-04-12 17:43:28,208 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : Received OpenSecureChannelResponse.
2018-04-12 17:43:28,209 DEBUG --- [ua-shared-pool-0] UaTcpClientMessageHandler : SecureChannel id=1698234672, currentTokenId=1, previousTokenId=-1, lifetime=3600000ms, createdAt=DateTime{utcTime=131680285860260000, javaDate=Thu Apr 12 19:43:06 CEST 2018}
2018-04-12 17:43:28,209 DEBUG --- [ua-netty-event-loop-1] UaTcpClientMessageHandler : 0 message(s) queued before handshake completed; sending now.
2018-04-12 17:43:28,209 DEBUG --- [ua-shared-pool-1] ClientChannelManager : Channel bootstrap succeeded: localAddress=/172.20.100.54:55806, remoteAddress=/172.20.100.135:4840
2018-04-12 17:43:28,210 DEBUG --- [ua-shared-pool-0] SessionFsm : S(Inactive) x E(CreateSessionEvent) = S'(Creating)
Exception in thread "main" java.util.concurrent.ExecutionException: UaException: status=Bad_SessionClosed, message=The session was closed by the client.
at java.base/java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:395)2018-04-12 17:43:28,212 DEBUG --- [ua-shared-pool-1] SessionFsm : Sending CreateSessionRequest...

at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1999)
at com.mycompany.opcua.participants.CommunicationMain.testClient(CommunicationMain.java:70)
at com.mycompany.opcua.participants.CommunicationMain.main(CommunicationMain.java:51)
Caused by: UaException: status=Bad_SessionClosed, message=The session was closed by the client.
at org.eclipse.milo.opcua.stack.core.util.FutureUtils.failedUaFuture(FutureUtils.java:100)
at org.eclipse.milo.opcua.stack.core.util.FutureUtils.failedUaFuture(FutureUtils.java:88)
at org.eclipse.milo.opcua.sdk.client.session.states.Inactive.(Inactive.java:28)
at org.eclipse.milo.opcua.sdk.client.session.SessionFsm.(SessionFsm.java:69)
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.(OpcUaClient.java:159)2018-04-12 17:43:28,212 INFO --- [NonceUtilSecureRandom] NonceUtil : SecureRandom seeded in 0ms.

at com.mycompany.opcua.participants.MyClient.(MyClient.java:112)
at com.mycompany.opcua.participants.CommunicationMain.testClient(CommunicationMain.java:60)
... 1 more

I use Eclipse milo 0.2.1 as OPC UA library.

Could you please tell me hat can cause this issue and how to fix it? Can it be a race condition related to this?

I can connect to the same server using other client (UaExpert).

Thank you in advance.

Solution

  • All of the calls you're making (connect(), disconnect(), and readValues()) are asynchronous, so what's likely happening here is you're not connected when you attempt the read.

    Make sure for these examples you block for the result before moving to the next step. (you're not doing this on connect())