Example: Distributed Live Dashboard

Two ensemble processes stream into a single LiveEventHub; a browser connects once and sees both runs side by side.

Prerequisites

The agentensemble-web-hub module on the hub process’s classpath.
The agentensemble-web module on each publisher process’s classpath.
OPENAI_API_KEY set in each publisher’s environment.

Step 1: start the hub

Terminal A:

./gradlew :agentensemble-examples:runDistributedDashboardHub

You should see:

  LiveEventHub started on port 7400
    Browser : ws://localhost:7400/ws
    Ingress : ws://localhost:7400/ingress
    REST    : http://localhost:7400/api/hub/producers

Step 2: open the browser

Navigate to http://localhost:7400/hub?server=ws://localhost:7400/ws. The producer sidebar is empty until publishers connect.

Step 3: start the first publisher

Terminal B:

./gradlew :agentensemble-examples:runDistributedDashboardPublisher \
    --args="ws://localhost:7400/ingress svc-a instance-1 \"Research AI trends in 2026\""

The browser sidebar shows svc-a as a producer chip. Click it to inspect the run.

Step 4: start the second publisher

Terminal C:

./gradlew :agentensemble-examples:runDistributedDashboardPublisher \
    --args="ws://localhost:7400/ingress svc-b instance-2 \"Write a marketing summary\""

Both producers appear in the sidebar simultaneously. Their task timelines update independently.

Step 5: late-join check

Refresh the browser mid-run. The hub re-sends a hub_hello containing the merged snapshotTrace; the page re-renders the same per-producer state without restarting any publisher.

Step 6: producer restart

Kill Terminal B. The browser shows a producer_left event. Restart B with the same producerId (the example derives it from serviceName-instanceId, so use the same args): the publisher re-attaches to its retained state and the browser resumes the timeline.