The Streams page

Nova's Streams page shows the StreamApp resources that run on the streaming bus. A stream reads one Kafka topic and writes one Iceberg table.

What you see

Each row is one StreamApp:

Column	Meaning
Name	The StreamApp name, with its owner group beneath it.
Phase	The phase the operator reports: Running, Stopped, Failed or Pending.
Source	The Connection (or the platform bus) and the Kafka topic the stream reads.
Sink	The catalog, table and mode (merge or append) the stream writes.
Checkpoint	When the stream last recorded its checkpoint.
Last error	The most recent error, if any.
Job	One Stop or Resume button.

The page shows the StreamApps of the groups you belong to; an administrator sees all of them. It polls every 15 seconds.

If nothing runs on the bus yet, the page is empty and says: "No streams yet. A stream is created as a StreamApp resource; ask an administrator to add one."

Stop and resume a stream

Stop sets spec.stopped: true; the operator deletes the Spark application and keeps the checkpoint. Resume sets it back to false and the job continues from that checkpoint, so no rows are lost or re-read from the start.

The button acts on one row and is disabled while that row's request is in flight. If the request fails, the API's sentence appears above the table and the button is enabled again; the page shows what the operator reports, so the phase does not change until the operator has reconciled. An administrator can do the same from the command line:

kubectl -n <namespace> patch streamapp <name> --type merge -p '{"spec":{"stopped":true}}'

See streams from the command line

kubectl get streamapps -n <namespace>

A StreamApp example

This example reads a topic and merges rows into an Iceberg table by key. It passes kubectl apply --dry-run=server on a cluster where the StreamApp resource is installed:

apiVersion: stardelt.io/v1alpha1
kind: StreamApp
metadata:
  name: pegelonline
  namespace: stardelt
spec:
  source:
    connectionRef: kafka-bus
    topic: pegelonline.measurements
  sink:
    catalog: shared
    table: bronze.pegelonline_measurements
    mode: merge
    mergeKeys:
      - station_uuid
      - measured_at

spec.stopped: true stops the job and keeps the checkpoint, so setting it back to false resumes from where it left off. Keyed merge sinks are effectively-once; append-only sinks (mode: append, no mergeKeys) are at-least-once. Credentials live in a Connection, never in the manifest.