Qfyilyi

I am new to OPC UA and I am using milo OPC Subscriber client to connect to local discovery service. I have Prosys simulation server which is connected to my local discovery service.

Note: If I connect directly to prosys endpoint it works fine. It fails only through discovery service.

I get the following exception when I run my code

<pre>12:38:35.916 [main] INFO org.eclipse.milo.opcua.stack.core.Stack -

Successfully removed cryptography restrictions. 12:38:36.167 [main]

INFO com.company.OpcuaClientRunner - security temp dir:

C:UsersZ003Z2YPAppDataLocalTempsecurity 12:38:36.173 [main] INFO

com.company.KeyStoreLoader - Loading KeyStore at

C:UsersZ003Z2YPAppDataLocalTempsecurityexample-client.pfx

12:38:37.594 [main] INFO com.company.OpcuaClientRunner - Using

endpoint: opc.tcp://<hostname>:4840 [None] 12:38:37.600 [main] INFO

org.eclipse.milo.opcua.sdk.client.OpcUaClient - Eclipse Milo OPC UA

Stack version: 0.2.3 12:38:37.600 [main] INFO

org.eclipse.milo.opcua.sdk.client.OpcUaClient - Eclipse Milo OPC UA

Client SDK version: 0.2.3 12:38:37.809 [NonceUtilSecureRandom] INFO

org.eclipse.milo.opcua.stack.core.util.NonceUtil - SecureRandom seeded

in 0ms. 12:38:37.815 [ua-netty-event-loop-1] ERROR

org.eclipse.milo.opcua.stack.client.handlers.UaTcpClientMessageHandler

- [remote=<hostname>/<IP>:4840] errorMessage=ErrorMessage{error=StatusCode{name=Bad_ServiceUnsupported,

value=0x800B0000, quality=bad}, reason=null} 12:38:53.828 [main] ERROR

com.company.OpcuaClientRunner - Error running client example:

UaException: status=Bad_Timeout, message=request timed out after

16000ms java.util.concurrent.ExecutionException: UaException:

status=Bad_Timeout, message=request timed out after 16000ms     

at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)

at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1895)

at com.company.OpcuaSubscriber.run(OpcuaSubscriber.java:49)     

at com.company.OpcuaClientRunner.run(OpcuaClientRunner.java:122)    

at com.company.OpcuaSubscriber.main(OpcuaSubscriber.java:120) Caused by:

org.eclipse.milo.opcua.stack.core.UaException: request timed out after

16000ms     

at org.eclipse.milo.opcua.stack.client.UaTcpStackClient.lambda$scheduleRequestTimeout$13(UaTcpStackClient.java:326)

at io.netty.util.HashedWheelTimer$HashedWheelTimeout.expire(HashedWheelTimer.java:581)

at io.netty.util.HashedWheelTimer$HashedWheelBucket.expireTimeouts(HashedWheelTimer.java:655)

at io.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:367)

at java.lang.Thread.run(Thread.java:748) 12:38:53.828 [main] ERROR

com.company.OpcuaClientRunner - Error running example: UaException:

status=Bad_Timeout, message=request timed out after 16000ms

java.util.concurrent.ExecutionException: UaException:

status=Bad_Timeout, message=request timed out after 16000ms     

at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)

at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1895)

at com.company.OpcuaSubscriber.run(OpcuaSubscriber.java:49)     

at com.company.OpcuaClientRunner.run(OpcuaClientRunner.java:122)    

at com.company.OpcuaSubscriber.main(OpcuaSubscriber.java:120) Caused by:

org.eclipse.milo.opcua.stack.core.UaException: request timed out after

16000ms     

at org.eclipse.milo.opcua.stack.client.UaTcpStackClient.lambda$scheduleRequestTimeout$13(UaTcpStackClient.java:326)

at io.netty.util.HashedWheelTimer$HashedWheelTimeout.expire(HashedWheelTimer.java:581)

at io.netty.util.HashedWheelTimer$HashedWheelBucket.expireTimeouts(HashedWheelTimer.java:655)

at io.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:367)

at java.lang.Thread.run(Thread.java:748)</pre>

Code to create client in ClientRunner.

private OpcUaClient createClient() throws Exception {

        File securityTempDir = new File(System.getProperty("java.io.tmpdir"), "security");

        if (!securityTempDir.exists() && !securityTempDir.mkdirs()) {

            throw new Exception("unable to create security dir: " + securityTempDir);

        }

        LoggerFactory.getLogger(getClass())

            .info("security temp dir: {}", securityTempDir.getAbsolutePath());



        KeyStoreLoader loader = new KeyStoreLoader().load(securityTempDir);

        loader.load();



        SecurityPolicy securityPolicy = client.getSecurityPolicy();

        EndpointDescription endpoints;



        try {

            endpoints = UaTcpStackClient

                .getEndpoints(client.getEndpointUrl())

                .get();

        } catch (Throwable ex) {

            ex.printStackTrace();

            // try the explicit discovery endpoint as well

            String discoveryUrl = client.getEndpointUrl();

            logger.info("Trying explicit discovery URL: {}", discoveryUrl);

            endpoints = UaTcpStackClient

                .getEndpoints(discoveryUrl)

                .get();

        }



        EndpointDescription endpoint = Arrays.stream(endpoints)

            .filter(e -> e.getSecurityPolicyUri().equals(securityPolicy.getSecurityPolicyUri()))

            .findFirst().orElseThrow(() -> new Exception("no desired endpoints returned"));

        logger.info("Using endpoint: {} [{}]", endpoint.getEndpointUrl(), securityPolicy);



        OpcUaClientConfig config = OpcUaClientConfig.builder()

            .setApplicationName(LocalizedText.english("eclipse milo opc-ua client"))

            .setApplicationUri("urn:eclipse:milo:examples:client")

            .setCertificate(loader.getClientCertificate())

            .setKeyPair(loader.getClientKeyPair())

            .setEndpoint(endpoint)

            .setIdentityProvider(client.getIdentityProvider())

            .setRequestTimeout(uint(5000))

            .build();



        return new OpcUaClient(config);

Client interface class

public interface OpcuaClientInterface {



        public static final String USERNAME = "demo";

        public static final String PASSWORD = "demo";



        default String getEndpointUrl() {

            return "opc.tcp://localhost:4840/UADiscovery";

        }



        default SecurityPolicy getSecurityPolicy() {

             return SecurityPolicy.None;

        }





        default IdentityProvider getIdentityProvider() {

    //       return new UsernameProvider(USERNAME,PASSWORD);

            return new AnonymousProvider();

        }



        void run (OpcUaClient client, CompletableFuture future) throws Exception;



    }

subscriber run implementation

    @Override

    public void run(OpcUaClient client, CompletableFuture future) throws Exception {

        // synchronous connect

        client.connect().get();



        // create a subscription @ 1000ms

        UaSubscription subscription = client.getSubscriptionManager().createSubscription(1000.0).get();



        List nodeIds = Arrays.asList("SuctionPressure", "DischargePressure", "Flow", "BearingTemperature", "Vibration", "Power");

//      List nodeIds = Arrays.asList("DS", "PV");



        List MICRs = nodeIds.stream().map(id -> {

            ReadValueId readValueId = new ReadValueId(new NodeId(3, id), AttributeId.Value.uid(), null,

                    QualifiedName.NULL_VALUE);



            // important: client handle must be unique per item

            UInteger clientHandle = uint(clientHandles.getAndIncrement());



            MonitoringParameters parameters = new MonitoringParameters(clientHandle, 1000.0, // sampling interval

                    null, // filter, null means use default

                    uint(10), // queue size

                    true // discard oldest

            );



            MonitoredItemCreateRequest request = new MonitoredItemCreateRequest(readValueId, MonitoringMode.Reporting,

                    parameters);

            return request;

        }).collect(Collectors.toList());



        // when creating items in MonitoringMode.Reporting this callback is where each

        // item needs to have its

        // value/event consumer hooked up. The alternative is to create the item in

        // sampling mode, hook up the

        // consumer after the creation call completes, and then change the mode for all

        // items to reporting.

        BiConsumer onItemCreated = (item, id) -> item

                .setValueConsumer(this::onSubscriptionValue);



        List items = subscription.createMonitoredItems(TimestampsToReturn.Both, MICRs, onItemCreated)

                .get();



        for (UaMonitoredItem item : items) {

            if (item.getStatusCode().isGood()) {

                logger.info("item created for nodeId={}", item.getReadValueId().getNodeId());

            } else {

                logger.warn("failed to create item for nodeId={} (status={})", item.getReadValueId().getNodeId(),

                        item.getStatusCode());

            }

        }



        // let the example run for 5 seconds then terminate

        // Thread.sleep(1000 * 60 * 1);

        // future.complete(client);

    }

I think you may be confused about what a Discovery Server does.

You don't connect "through" a Discovery Server to another server. It's more like a registry where other servers can register themselves and then clients can go and see what servers are available.

The client queries the discovery server for a list of servers, selects one, and then connects directly to that server using the information obtained from the discovery server.

I got it working with the milo OPC Subscriber client.

following is the changes I did in the classes.

Client Interface

public interface OpcuaClientInterface {



public static final String USERNAME = "demo";

public static final String PASSWORD = "demo";

public static final String UaServerName = "SimulationServer";



default String getEndpointUrl() {

    return "opc.tcp://localhost:4840";

}



default SecurityPolicy getSecurityPolicy() {

     return SecurityPolicy.None;

}



default String getUaServerName () {

    return UaServerName;

}





default IdentityProvider getIdentityProvider() {

     return new UsernameProvider(USERNAME,PASSWORD);

}



void run (OpcUaClient client, CompletableFuture<OpcUaClient> future) throws Exception;

}

client runner class

public class OpcuaClientRunner {



static {

    CryptoRestrictions.remove();

    Security.addProvider(new BouncyCastleProvider());

}

private final AtomicLong requestHandle = new AtomicLong(1L);



private final Logger logger = LoggerFactory.getLogger(getClass());

private final CompletableFuture<OpcUaClient> future = new CompletableFuture<>();



private final OpcuaClientInterface client;



public OpcuaClientRunner(OpcuaClientInterface client) throws Exception {

    this.client = client;

}



private KeyStoreLoader createKeyStore() {

    KeyStoreLoader loader = null;

    try {

        File securityTempDir = new File(System.getProperty("java.io.tmpdir"), "security");

        if (!securityTempDir.exists() && !securityTempDir.mkdirs()) {

            throw new Exception("unable to create security dir: " + securityTempDir);

        }

        LoggerFactory.getLogger(getClass()).info("security temp dir: {}", securityTempDir.getAbsolutePath());

        loader = new KeyStoreLoader().load(securityTempDir);

        loader.load();

    } catch (Exception e) {

        logger.error("Could not load keys {}", e);

        return null;

    }

    return loader;

}



private CompletableFuture<ServerOnNetwork> findServersOnNetwork(String discoveryEndpointUrl)

        throws InterruptedException, ExecutionException {

    UaStackClient c = createDiscoveryClient(client.getEndpointUrl()).connect().get();

    RequestHeader header = new RequestHeader(NodeId.NULL_VALUE, DateTime.now(),

            uint(requestHandle.getAndIncrement()), uint(0), null, uint(60), null);



    FindServersOnNetworkRequest request = new FindServersOnNetworkRequest(header, null, null, null);



    return c.<FindServersOnNetworkResponse>sendRequest(request).thenCompose(result -> {

        StatusCode statusCode = result.getResponseHeader().getServiceResult();



        if (statusCode.isGood()) {

            return CompletableFuture.completedFuture(result.getServers());

        } else {

            CompletableFuture<ServerOnNetwork> f = new CompletableFuture<>();

            f.completeExceptionally(new UaException(statusCode));

            return f;

        }

    });

}



private UaTcpStackClient createDiscoveryClient(String endpointUrl) {

    KeyStoreLoader loader = createKeyStore();

    if (loader == null) {

        return null;

    }

    UaTcpStackClientConfig config = UaTcpStackClientConfig.builder()

            .setApplicationName(LocalizedText.english("Stack Example Client"))

            .setApplicationUri(String.format("urn:example-client:%s", UUID.randomUUID()))

            .setCertificate(loader.getClientCertificate()).setKeyPair(loader.getClientKeyPair())

            .setEndpointUrl(endpointUrl).build();



    return new UaTcpStackClient(config);

}



private OpcUaClient createUaClient() throws Exception {



    KeyStoreLoader loader = createKeyStore();

    if (loader == null) {

        return null;

    }



    SecurityPolicy securityPolicy = client.getSecurityPolicy();

    EndpointDescription endpoints = null;



    try {

        ServerOnNetwork servers = findServersOnNetwork(client.getEndpointUrl()).get();

        ServerOnNetwork server = Arrays.stream(servers)

                .filter(e -> e.getServerName().equals(client.getUaServerName())).findFirst()

                .orElseThrow(() -> new Exception("no desired UA Server returned."));

        endpoints = UaTcpStackClient.getEndpoints(server.getDiscoveryUrl()).get();

    } catch (Throwable ex) {

        ex.printStackTrace();

    }



    EndpointDescription endpoint = Arrays.stream(endpoints)

            .filter(e -> e.getSecurityPolicyUri().equals(securityPolicy.getSecurityPolicyUri())).findFirst()

            .orElseThrow(() -> new Exception("no desired endpoints returned"));

    logger.info("Using endpoint: {} [{}]", endpoint.getEndpointUrl(), securityPolicy);



    OpcUaClientConfig config = OpcUaClientConfig.builder()

            .setApplicationName(LocalizedText.english("eclipse milo opc-ua client"))

            .setApplicationUri("urn:eclipse:milo:examples:client").setCertificate(loader.getClientCertificate())

            .setKeyPair(loader.getClientKeyPair()).setEndpoint(endpoint)

            .setIdentityProvider(client.getIdentityProvider()).setRequestTimeout(uint(5000)).build();



    return new OpcUaClient(config);

}



public void run() {

    try {

        OpcUaClient uaClient = createUaClient();

        future.whenComplete((c, ex) -> {

            if (ex != null) {

                logger.error("Error running example: {}", ex.getMessage(), ex);

            }



            try {

                uaClient.disconnect().get();

                Stack.releaseSharedResources();

            } catch (InterruptedException | ExecutionException e) {

                logger.error("Error disconnecting:", e.getMessage(), e);

            }



            try {

                Thread.sleep(1000);

                System.exit(0);

            } catch (InterruptedException e) {

                e.printStackTrace();

            }

        });



        try {

            client.run(uaClient, future);

            future.get(15, TimeUnit.SECONDS);

        } catch (Throwable t) {

            logger.error("Error running client example: {}", t.getMessage(), t);

            future.completeExceptionally(t);

        }



    } catch (Throwable t) {

        logger.error("Error getting client: {}", t.getMessage(), t);



        future.completeExceptionally(t);



        try {

            Thread.sleep(1000);

            System.exit(0);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }



    /*

     * try { Thread.sleep(999999999); } catch (InterruptedException e) {

     * e.printStackTrace(); }

     */

}

}