Kafka - Schema Registry

About

schema registry

Schema registry is recommended if you plan to use Avro for a data format because it can help you with:

• serialization
• and schema evolution.

Articles Related

Connector

with schema knowledge

• the Avro converter that comes with the schema registry,
• or the JSON converter with schemas enabled.

Management

Start

• Localhost: Start the Schema Registry in its own terminal.

./bin/schema-registry-start ./etc/schema-registry/schema-registry.properties

• Docker

docker run -d \
  --net=host \
  --name=schema-registry \
  -e SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL=localhost:32181 \
  -e SCHEMA_REGISTRY_HOST_NAME=localhost \
  -e SCHEMA_REGISTRY_LISTENERS=http://localhost:8081 \
  confluentinc/cp-schema-registry:4.0.0

Produce with Schema registry

create data with a schema. See Kafka - kafka-avro-console-producer utility

Compatibility level

You can change the compatibility level of Schema Registry to allow incompatible schemas or other compatibility levels. There are two ways to do this:

• Set the compatibility level for subjects which are used by the connector using PUT /config/(string: subject).
• Configure the Schema Registry to use other schema compatibility level by setting avro.compatibility.level in Schema Registry. Note that this is a global setting that applies to all schemas in the Schema Registry.

Subject

The subjects have format of topic-key and topic-value where the topic is determined by topic.prefix config and table name.

Documentation / Reference

• https://docs.confluent.io/current/schema-registry/docs/intro.html#schemaregistry-intro