Avro LogicalType Conversion

Table of Contents

• Purpose
• Running
  • Prerequisites
  • Demo
  • Tests
• Notes

Purpose

This source demonstrates how to use a simple Avro logical type Conversion.

In this example we use java.time.ZonedDateTime with an underlying Avro string.

As an example, we use a simple Java class with an optional event name and a time:

public final class AvroEvent {
  @org.apache.avro.reflect.Nullable
  public String name;

  public ZonedDateTime time;
}

Via getSchema(AvroEvent.class) we get the Avro schema in JSON format:

{
  "type" : "record",
  "name" : "AvroEvent",
  "namespace" : "com.fillmore_labs.avro.logicaltypes",
  "doc" : "Type documentation",
  "fields" : [ {
    "name" : "name",
    "type" : [ "null", "string" ],
    "default" : null
  }, {
    "name" : "time",
    "type" : {
      "type" : "string",
      "logicalType" : "zoneddatetime-string"
    }
  } ]
}

and can now serialize and deserialize this class to Avro format.

Running

Prerequisites

You need Bazelisk installed, with HomeBrew just use brew install bazelisk.

Demo

bazel run //:main

in the resulting log we first see the schema, then the original, encoded and decoded value.

Since the encoded value is binary, non-ASCII characters are replaced by dots.

Tests

To run all tests, use

bazel test //src/test/...

Notes

For a more elaborate example see Kafka Serialization Playground.