Basic Stream Worker Example

This example provides an introduction to the concept of a stream worker.

A stream worker provides an isolated execution environment for processing the execution logic. It can be deployed and processed independently of other stream workers in the system. Stream workers can use inMemory, c8db, and c8stream sources and sinks to communicate between each other.

Example

This example creates a Macrometa data stream to consume events from stream workers:

CREATE STREAM TemperatureStream (sensorId string, temperature double);

This example creates a sink to publish events from stream workers:

CREATE SINK TemperatureOnlyStream WITH (type='inMemory', topic='Temperature') (temperature double);

@info(name = 'Simple-selection')
insert into TemperatureOnlyStream
select temperature
from TemperatureStream;

Input

When an event ['aq-14', 35.4] is pushed via the SensorDetail topic of the inMemory transport from another stream worker, the event is consumed and mapped to the TemperatureStream stream.

Output

After processing, the event [35.4] arriving at TemperatureOnlyStream is emitted via Temperature topic of the inMemory transport to other subscribed stream workers.