README

SchemaGenerator takes in multiple JsonElements and creates an Avro Schema that can handle all cases given.

Uses Gson (gradle: com.google.code.gson:gson:2.3) for the JSON parsing.

You can find this Kotlin-package in Maven at https://bintray.com/arbetsformedlingen

// Generate Schema

val jsonExample1 = JsonParser().parse("{'name1' : 5}")
val jsonExample2 = JsonParser().parse("{'name2':{'name3': 'my value'}}")

val avroGenerator = SchemaGenerator(jsonExample1, "MyExample", "Testing my schema", "MyNamespace")

avroGenerator.addExample(jsonExample2) // add as many examples as you like

val schema = avroGenerator.generateSchema()

// Print Schema

println(schema.toString(true))

// Parse JSON from Schema

val example1: GenericRecord =
Parse.avroRecordFromJson(jsonExample1.asJsonObject, schema)  // if you know it's a JsonObject
val example2: Any = Parse.avroObjectFromJson(jsonExample1, schema)!!  // if you don't know the Json type

// Show how to send both examples to Kafka:

val props = Properties()
props["bootstrap.servers"] = "kafkadomain.com:9092"
props["key.serializer"] = StringSerializer::class.java
props["value.serializer"] = KafkaAvroSerializer::class.java
props["schema.registry.url"] = "https://kafkadomain.com:8081"

if (false) { // Don't send as the kafka urls are just examples
val kafkaProducer = KafkaProducer<String, GenericRecord>(props)

kafkaProducer.send(ProducerRecord("MyTopic", "MyExampleKey1", example1))
kafkaProducer.send(ProducerRecord("MyTopic", "MyExampleKey2", example2 as GenericRecord))
}

Parameters

rootNodeJson - First JSON example e.g. JsonParser().parse("{'test':5}"). Use addExample to add more.

rootName - a JSON string providing the name of the record. Will be put in the root node of the schema.

rootDoc - a JSON string providing documentation to the user of this schema. Will be put in the root node of the schema.

rootNamespace - a JSON string that qualifies the namespace. Will be put in the root node of the schema.

Constructors

Name	Signature	Comments
<init>	AvroSchemaGenerator(rootNodeJson: JsonElement, rootName: String, rootDoc: String, rootNamespace: String)	AvroSchemaGenerator takes in multiple JsonElements and creates an Avro Schema that can handle all cases given.

Functions

Name	Signature
addExample	fun addExample(rootNodeJson: JsonElement): Unit
generateSchema	fun generateSchema(): Schema