download - https://mvnrepository.com/artifact/org.apache.avro/avro-tools/1.8.2

use to print avro files in readable format :

• java -jar avro-tools.jar tojson --pretty customer-generic.avro
• java -jar avro-tools-1.8.2.jar getschema customer-generic. Avro

There are 3 types of schema evolutions

• Backward compatible: use new schema to read old data
  • example : adding new field with default value
• Forward compatible : use old schema to read new data
  • example : adding new field with default value
  • Full compatible :
    • Only add fields with defaults
    • only remove fields with defaults

• Store and retrieve schemas for producers / consumers
• Enforce Backward/forward / fully compatible on topics
• Decrease the size of the payload of data sent to Kafka

• Add schema
• retrieve schema
• update schema
• delete a schema
• all through using REST API
• Schemas can be applied to Key and values

# console producer
kafka-avro-console-producer \
--broker-list 192.168.99.100:9092 \
--topic test-avro \
--property schema.registry.url=http://127.0.0.1:8081 \
--property value.schema='
{"type":"record","name":"myrecord",
"fields":[{"name":"f1","type":"string"}]    
}'