This application helps in reconciling desired vs actual state when using the Eclipse Ditto digital twin platform.

The logic used is:

• Ditto events are read from a Kafka topic, exported by a Ditto Kafka connection
  • Change events must be normalized, and have "extraFields" for the properties which should be reconciled
  • It is possible to use filters
• When a change events comes along it will compare the desired state to the actual state
• If there is a discrepancy, it will send a command to Drogue Cloud in the form of:
  • Thing ID mapped to Application/Device
  • Command name is the feature
  • Command payload is the desired property value

Possible TODOs:

• Rate limit the commands
• Allow scheduling re-check/re-try
• Need a way to handle stale events
• Delete the desired property one it was confirmed

This project uses Quarkus, the Supersonic Subatomic Java Framework.

If you want to learn more about Quarkus, please visit its website: https://quarkus.io/ .

You can run your application in dev mode that enables live coding using:

./mvnw compile quarkus:dev

NOTE: Quarkus now ships with a Dev UI, which is available in dev mode only at http://localhost:8080/q/dev/.

The application can be packaged using:

./mvnw package

It produces the quarkus-run.jar file in the target/quarkus-app/ directory. Be aware that it’s not an über-jar as the dependencies are copied into the target/quarkus-app/lib/ directory.

The application is now runnable using java -jar target/quarkus-app/quarkus-run.jar.

If you want to build an über-jar, execute the following command:

./mvnw package -Dquarkus.package.type=uber-jar

The application, packaged as an über-jar, is now runnable using java -jar target/*-runner.jar.

You can create a native executable using:

./mvnw package -Pnative

Or, if you don't have GraalVM installed, you can run the native executable build in a container using:

./mvnw package -Pnative -Dquarkus.native.container-build=true

You can then execute your native executable with: ./target/ditto-reconciler-1.0.0-SNAPSHOT-runner

If you want to learn more about building native executables, please consult https://quarkus.io/guides/maven-tooling.