A Kafka Streams application to continuously populate the epics2kafka epics-channels topic from the JAWS alarm-instances topic for the subset of messages containing source type EPICSSource.

• Overview
• Quick Start with Compose
• Install
• Configure
• Build
• Release
• See Also

This app keeps epics2kafka automatically configured based on the JAWS configuration. This Kafka Streams app consumes the alarm-instances topic and looks for registration messages related to EPICS and for each of those produces a command message to epics2kafka via the epics-channels topic.

When a JAWS registration is removed it is removed via a tombstone message, which is a null value for a given key. This presents a challenge as a registration removal does not have a value payload to indicate whether it is an EPICS registration or what is the PV/channel name. The epics2kafka epics-channels topic key contains a PV/channel whereas the JAWS alarm-instances key is an alarm name. To overcome this challenge this app is not stateless, it uses a Kafka Streams store to track all JAWS registration records that have been used to command epics2kafka. This way the registration record key, the alarm name, can be used in the tombstone case to lookup if the tombstone means action is needed.

1. Grab project

git clone https://github.com/JeffersonLab/jaws-registrations2epics
cd jaws-registrations2epics

2. Launch Compose

docker compose up

3. Monitor the epics-channels command topic for updated channels to monitor

docker exec kafka kafka-console-consumer.sh --bootstrap-server kafka:9092 --topic epics-channels --from-beginning --property "print.key=true" --property "key.separator==" 

4. Register an alarm

docker exec -it jaws set_instance alarm1 --pv channel1 

See: Docker Compose Strategy

This application requires a Java 11+ JVM and standard library to run.

Download from Releases or build yourself.

Start scripts are created and dependencies collected by the Gradle distribution target:

gradlew assembleDist

Launch with:

UNIX:

bin/jaws-regisrations2epics

Windows:

bin/jaws-registrations2epics.bat

Environment Variables

This project is built with Java 17 (compiled to Java 11 bytecode), and uses the Gradle 7 build tool to automatically download dependencies and build the project from source:

git clone https://github.com/JeffersonLab/registrations2epics
cd registrations2epics
gradlew build

Note: If you do not already have Gradle installed, it will be installed automatically by the wrapper script included in the source

Note for JLab On-Site Users: Jefferson Lab has an intercepting proxy

See: Docker Development Quick Reference

1. Bump the version number in build.gradle and commit and push to GitHub (using Semantic Versioning).
2. Create a new release on the GitHub Releases page corresponding to same version in build.gradle (Enumerate changes and link issues). Run dist build and attach zip to release.
3. Publish to DockerHub GitHub Action should run automatically.
4. Bump and commit quick start image version after confirming new image works

• Developer Notes