CODEWITHSUNDEEP
spring-bootapache-camelopc-uamilo
marcello cappelli
marcello cappelli

Reputation: 31

Methods in OPC-UA Apache-Camel Milo Client

A few months ago I started working on a project that requires the integration of OPC / UA to communicate with an automatic machine. Working with SpringBoot I looked for a library that was well integrated with this framework and in several posts and thesis I found Eclipse Milo, but in the version integrated with Apache Camel. Not knowing either Camel or Milo, I had to study both at least.

Camel has a huge documentation, while the integration with Milo is limited to the parameterization and configuration of the Nodes to perform the reading and writing. That said it seems more than enough but in reality, since there are no specific examples, I had to search for posts several times to understand where I was wrong and clearly it took a lot of time.

Now for example, I was able to run the reads and writes correctly while the function calls have a strange behavior, that is, every time I call the test function, the value that is returned to me is the parameter that I give in input, even if, enabling the TRACE on Camel and Milo I see that the function is called correctly and in the OutputArguments there is the result I expect but Camel keeps returning the InputArguments. It's certainly my mistake but I can't find anything to help me understand where I'm wrong. Is the choice I made the right one? I don't know what else to try.

Here the test simplified code I'm trying to do:

Variant[] params = new Variant[1];
params[0] = new Variant(13);

String  endpointUri = "milo-client:opc.tcp://milo.digitalpetri.com:62541/milo?node=RAW(ns=2;s=Methods)"&method=RAW(ns=2;s=Methods/sqrt(x))";
return producerTemplate.requestBody(endpointUri, params, "await", true, Variant.class);

The returned object is the same as I input, even if looking at the log I see that the function call is executed correctly:

 2021-mag-20 11:14:07.613 TRACE [milo-netty-event-loop-1] o.e.m.o.s.c.t.t.OpcTcpTransport - Write succeeded for request=PublishRequest, requestHandle=16
 2021-mag-20 11:14:07.598 DEBUG [milo-shared-thread-pool-1] o.a.c.c.m.c.i.SubscriptionManager - Call to node=ExpandedNodeId{ns=2, id=Methods, serverIndex=0}, method=ExpandedNodeId{ns=2, id=Methods/sqrt(x), serverIndex=0} = [Variant{value=13.0}]-> CallMethodResult{StatusCode=StatusCode{name=Good, value=0x00000000, quality=good}, InputArgumentResults=[StatusCode{name=Good, value=0x00000000, quality=good}], InputArgumentDiagnosticInfos=[], OutputArguments=[Variant{value=3.605551275463989}]}

This are my dependencies :

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-spring-boot-starter</artifactId>
  <version>3.9.0</version>
</dependency>        
<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-milo-starter</artifactId>
  <version>3.9.0</version>
</dependency>

Upvotes: 0

Views: 652

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