Schema Registry Client

This repository contains wrapper function to communicate Confluent's Kafka schema registry via REST API and schema dynamic sync directly from kafka topic.

Client

Download library using go get -u github.com/tryfix/schema-registry/v2

Following code slice create a schema registry client

import schemaregistry "github.com/tryfix/schemaregistry/v2"

registry, _ := NewRegistry(
		`http://localhost:8081/`,
		WithBackgroundSync(5*time.Second),
	)

Register an event com.example.events.test with version 1

import schemaregistry "github.com/tryfix/schemaregistry/v2"

if err := registry.Register(`com.example.events.test`, 1, func(unmarshaler Unmarshaler) (v interface{}, err error) {
		record := SampleRecord{}
		if err := unmarshaler.Unmarshal(&record); err != nil {
			return nil, err
		}

		return record, nil
	}); err != nil {
		log.Fatal(err)
	}

Message encoding/decoding using above registered schema

// avro message structure
type SampleRecord struct {
Field1 int     `avro:"field1"`
Field2 float64 `avro:"field2"`
Field3 string  `avro:"field3"`
}

// Get encoder  
encoder := registry.WithSchema(`com.example.events.test`, 1)

// Sample message
record := SampleRecord{
Field1: 1,
Field2: 2.0,
Field3: "text",
}

// Message encode to byte array
bytePayload, err := encoder.Encode(record)
if err!=nil {
    panic(err)
}

// Decode message
ev, err := encoder.Decode(bytePayload)
if err != nil {
panic(err)
}
fmt.Printf("%+v", ev)

Message can be decoded through generic encoder as below

// Decode message as generic encoder
ev, err := registry.GenericEncoder().Decode(bytePayload) // Returns SampleRecord
if err != nil {
panic(err)
}

Message Structure

Encoded messages are published with magic byte and a schema ID attached to it. Following structure shows the message format used in the library to encode the message.

+====================+=== =================+======================+
| Magic byte(1 byte) | Schema ID(4 bytes) | Payload              |
+====================+====================+======================+

ToDo

• write benchmarks