Can not get response from LwM2M clients when using CoAP+TCP (java-coap) #1675
Comments
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Thx for taking time to reporting that. 🙏 Glad to see that you are testing coap+tcp experimental feature. I will try to look at this but maybe not today 😬 Some remarks waiting I take time to look at this deeper :
a null response with synchronous send API means that the request timeout.
I see you are using synchronous send API in /**
* Listen for client registration events.
* <p>
* Those methods are called by the protocol stage thread pool, this means that execution MUST be done in a short delay,
* if you need to do long time processing use a dedicated thread pool.
*/Could you try with async send API ? |
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Thank you! I will try that sometime later. Instead of doing CoAP over TCP, for now I've decided to try if WebSocket proxy would work, as defined in Section 4 of RFC 8323. |
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I'm able to reproduce that but using async way to send request, it works for me, with : lwm2mServer.getRegistrationService().addListener(new RegistrationListener() {
@Override
public void registered(Registration registration, Registration previousReg,
Collection<org.eclipse.leshan.core.observation.Observation> previousObservations) {
LOG.info("new device: {}", registration.getEndpoint());
lwm2mServer.send(registration, new ReadRequest(3, 0, 13), response -> {
if (response.isSuccess()) { // <-- error: response is null when using CoAP over TCP
LOG.info("Device time: {}", ((LwM2mResource) response.getContent()).getValue());
} else {
LOG.info("Failed to read: {} {}", response.getCode(), response.getErrorMessage());
}
}, e -> LOG.error("Unexpected error while reading device time", e));
}
@Override
public void updated(RegistrationUpdate update, Registration updatedReg, Registration previousReg) {
LOG.info("device is still here: {}", updatedReg.getEndpoint());
}
@Override
public void unregistered(Registration registration,
Collection<org.eclipse.leshan.core.observation.Observation> observations, boolean expired,
Registration newReg) {
LOG.info("device left: {}", registration.getEndpoint());
}
});I get |
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I looked at your problem a bit deeper and try to investigate about the sync way you used. I confirm the NPE is because you don't handle the timeout correctly. Code should looks like : lwm2mServer.getRegistrationService().addListener(new RegistrationListener() {
@Override
public void registered(Registration registration, Registration previousReg,
Collection<org.eclipse.leshan.core.observation.Observation> previousObservations) {
LOG.info("new device: {}", registration.getEndpoint());
try {
ReadResponse response = lwm2mServer.send(registration, new ReadRequest(3, 0, 13), TIMEOUT_IN_MS);
if (response == null) {
LOG.info("Read 'Device Time' timeout");
} else if (response.isSuccess()) { // <-- error: response is null when using CoAP over TCP
LOG.info("Device time: {}", ((LwM2mResource) response.getContent()).getValue());
} else {
LOG.info("Failed to read: {} {}", response.getCode(), response.getErrorMessage());
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
LOG.error("Interrupted while reading device time", e);
} catch (Exception e) {
LOG.error("Unexpected error while reading device time", e);
}
}
@Override
public void updated(RegistrationUpdate update, Registration updatedReg, Registration previousReg) {
LOG.info("device is still here: {}", updatedReg.getEndpoint());
}
@Override
public void unregistered(Registration registration,
Collection<org.eclipse.leshan.core.observation.Observation> observations, boolean expired,
Registration newReg) {
LOG.info("device left: {}", registration.getEndpoint());
}
});But even with a cleaner code like ☝️, Sync send will not work because this code is executed in Netty NioEventLoopGroup and it should not contain blocking code. I'm not 100% sure but, my understanding : Anyway, I think the right way to do is to use Async Send API. By the way the /**
* Listen for client registration events.
* <p>
* Those methods are called by the protocol stage thread pool, this means that execution MUST be done in a short delay,
* if you need to do long time processing use a dedicated thread pool.
*/HTH |
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@max-pv please let us know if you move forward on that and also If we should close this issue ? |
Version(s)
2.0.0-M16
Which components
leshan-lwm2m-server
Tested With
Leshan Client Demo, Anjay Demo
What happened
When running a Leshan demo a server with a RegistrationListener from Wiki and using Leshan Client (or another LwM2M client) with CoAP+TCP server address, the server timeouts and throws the error from the "relevant output" section.
It works fine when using plain CoAP provider (just
coap://scheme)How to reproduce
mvn clean installjava -jar ./leshan-demo-server/target/leshan-demo-server-*-SNAPSHOT-jar-with-dependencies.jar -vvvjava -jar leshan-demo-client/target/leshan-demo-client-*-SNAPSHOT-jar-with-dependencies.jar -u coap+tcp://localhost:5683 -n tcp-device-1Relevant Output
The text was updated successfully, but these errors were encountered: