Topic (Source)
Description
Topic Source allows to read events from the Kafka topic hosted Nussknacker Cloud ("internal topics"). You can use internal Kafka topics to:
- route data between scenarios
- send events to a topic via public HTTPS or WebSocket endpoint
- receive results via HTTP callback or WebSocket subscription
Use the Topic link (top right of the Designer window) to create a topic; read this document to learn how to create a Nussknacker Cloud hosted Kafka topic.
Parameters and configuration
| Name | Description |
|---|---|
| Topic name | Kafka topic to write to |
| Version | Schema version |
Advanced parameters
| Name | Description |
|---|---|
| Event time | Expression which evaluates to the time when the event was created. For Kafka sources, creation timestamp is available in the Kafka event and can be accessed in SpEL as #inputMeta.timestamp. Check here |
| Max out-of-orderness | The maximum amount of time an element is allowed to be late before being ignored when computing the result for time-based stream transformations: aggregates in time windows and joins. To read more about this mechanism see Flink documentation |
| Idleness | The time period after which partition is marked as idle if no events are received from it. To read more about this mechanism see Flink documentation. |