Schema Registry — Central Schema Management for Streaming

Schema Registry centralizes and versions schemas for messaging systems. Compatibility checks ensure safe evolution without breaking changes.

Schema Registry in Kafka¶

Centralizes and versions schemas, enforces compatibility.

Avro Schema¶

{
  "type": "record",
  "name": "Order",
  "namespace": "cz.core.events",
  "fields": [
    {"name": "order_id", "type": "string"},
    {"name": "total_czk", "type": {"type": "bytes", "logicalType": "decimal", "precision": 12, "scale": 2}},
    {"name": "status", "type": {"type": "enum", "name": "Status", "symbols": ["PENDING", "CONFIRMED", "SHIPPED"]}},
    {"name": "notes", "type": ["null", "string"], "default": null}
  ]
}

Compatibility Modes¶

• BACKWARD — new consumer, old producer
• FORWARD — old consumer, new producer
• FULL — both (safest)

from confluent_kafka.schema_registry import SchemaRegistryClient
from confluent_kafka.schema_registry.avro import AvroSerializer

registry = SchemaRegistryClient({'url': 'http://registry:8081'})
serializer = AvroSerializer(registry, schema_str)
producer.produce('orders', value=serializer(order, ctx))

Summary¶

Schema Registry is essential for production Kafka. Versioning and compatibility checks prevent runtime errors.