Stream topology in Kafka - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a stream topology in Kafka Streams?

A stream topology is a directed graph that defines the flow of data through various processing steps in a Kafka Streams application. It shows how streams and tables are connected and processed.

beginner

Name the main components of a Kafka Streams topology.

The main components are:

• Source nodes (where data enters)
• Processor nodes (where data is processed)
• Sink nodes (where data is sent out)

intermediate

How do you build a stream topology in Kafka Streams?

You use the <code>StreamsBuilder</code> class to define sources, processors, and sinks, then call <code>build()</code> to create the topology.

intermediate

What is the role of a Processor API in stream topology?

The Processor API lets you define custom processing logic by creating processor nodes that can transform, filter, or join streams within the topology.

beginner

Explain the difference between source and sink nodes in a stream topology.

Source nodes read data from Kafka topics into the topology. Sink nodes write processed data back to Kafka topics or external systems.

Which Kafka Streams class is used to build a stream topology?

A KafkaProducer

B StreamsBuilder

C KafkaConsumer

D TopologyBuilder

StreamsBuilder is the class used to define sources, processors, and sinks to build a stream topology.

In a stream topology, what does a sink node do?

A Writes data to Kafka topics or external systems

B Processes data inside the topology

C Stores data in memory

D Reads data from Kafka topics

Sink nodes write processed data out to Kafka topics or external systems.

What is the purpose of processor nodes in a Kafka Streams topology?

A To write data to external databases

B To read data from Kafka topics

C To apply custom processing logic on streams

D To monitor Kafka cluster health

Processor nodes apply custom logic like filtering, transforming, or joining streams.

Which of the following best describes a stream topology?

A A list of Kafka topics

B A configuration file for Kafka brokers

C A database schema

D A graph showing data flow and processing steps

A stream topology is a directed graph showing how data flows and is processed.

How do you finalize the definition of a stream topology in Kafka Streams?

A Call <code>build()</code> on StreamsBuilder

B Call <code>start()</code> on StreamsBuilder

C Call <code>connect()</code> on KafkaConsumer

D Call <code>send()</code> on KafkaProducer

Calling build() on StreamsBuilder creates the topology object.

Describe the components of a Kafka Streams topology and their roles.

Think about where data enters, how it is processed, and where it goes out.

Explain how you would create and build a stream topology using Kafka Streams API.

Focus on the steps from starting with StreamsBuilder to getting the topology object.