Topic name strategy

As explained in Kafka Streams in Action, Second Edition

TopicNameStrategy is a Schema Registry subject naming strategy that derives separate key and value subject names from a Kafka topic name.

TopicNameStrategy is Schema Registry’s default subject naming strategy. It derives separate subjects from the Kafka topic name: <topic>-key for keys and <topic>-value for values. section 3.3.1

Because the subject is scoped to a topic, each topic supports one data type per key or value subject. This fits topics named for the event type they contain. section 3.3.1

Use the strategy when:

• Keep one record type on a topic and let Schema Registry enforce compatible changes within that topic. section 3.3.1 section 3.3
• Reuse the same record type on different topics while allowing each topic to register a different schema. section 3.3.1
• Choose another strategy when closely related event types must share one topic without a fixed single type. section 3.3.1

Subjects for an inventory topic

For a topic named inventory-events, register the value schema under inventory-events-value and a key schema under inventory-events-key. No additional strategy configuration is required because TopicNameStrategy is the default. To place PlaneEvent, TruckEvent, and DeliveryEvent together while retaining an allowed set of types, use an Avro union registered under the topic’s value subject with schema references. section 3.3.1 section 3.6

Figure 3.6 TopicNameStrategy enforces having the same type of domain object represented by the registered schema for the value and or the key.

Use the figure to compare how topic-scoped subjects constrain the domain-object type represented by a key or value schema. section 3.3.1

How Kafka Streams in Action, Second Edition covers it

How deep it goes

Explains subject naming, topic-level type constraints, cross-topic schema independence, and schema-reference composition, but defers client implementation details.

Examples

Uses key/value subject names, event-type-named topics, and a retailer’s PlaneEvent, TruckEvent, and DeliveryEvent union.

What it assumes

Assumes Kafka topics and Schema Registry subjects while establishing key-versus-value schemas and compatibility scope.

What you can do after

Apply it via Schema Registry by deriving <topic>-key and <topic>-value subjects and choosing references when one topic needs related event types.

How it connects

Connects Schema Registry subjects, schema compatibility, schema references, Avro unions, RecordNameStrategy, and TopicRecordNameStrategy.

liveBookmanning.com

Read Kafka Streams in Action, Second Edition on liveBook Get the book at manning.com

Also explained in

• 

  liveBookmanning.com
  Kafka for ArchitectsTopicNameStrategy is a Schema Registry subject-naming strategy that groups schema versions by Kafka topic and message component.

Compare how 2 books explain topic name strategy →

Related concepts

• schema referenceused by · A schema reference is a link from one schema to another schema definition, enabling reuse of shared data-structure definitions.
• subject name strategykind of · A subject name strategy is a rule that determines how Schema Registry subject names are derived and therefore where compatibility is checked.
• subjectuses · A subject is a Schema Registry identifier that groups versions of a schema governing a particular event type, topic, or key or value stream.
• topic record name strategycontrasts with · TopicRecordNameStrategy is a Schema Registry subject-naming strategy that derives subjects from a Kafka topic name and a record’s fully qualified name.
• topicuses · A topic is a named messaging destination or stream to which producers publish messages or records and from which consumers receive or read them.
• schema registryused by · A schema registry is a service that stores, versions, and provides schemas for structured data, often validating compatibility between schema versions.

This explainer was generated by Manning's knowledge graph from the text of Kafka Streams in Action, Second Edition. The section links point to the parts of the book it draws on.