Kafka Stream with Avro in JAVA , schema.registry.url” which has no default value

I have the following configuration for my Kafka Stream application

    Properties config = new Properties();
    config.put(StreamsConfig.APPLICATION_ID_CONFIG,this.applicaionId);
    config.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG,svrConfig.getBootstrapServers());
    config.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");

    // we disable the cache to demonstrate all the "steps" involved in the transformation - not recommended in prod
    config.put(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, svrConfig.getCacheMaxBytesBufferingConfig());

    // Exactly once processing!!
    config.put(StreamsConfig.PROCESSING_GUARANTEE_CONFIG, StreamsConfig.EXACTLY_ONCE);
    config.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG,SpecificAvroSerde.class);
    config.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG,SpecificAvroSerde.class);
    config.put(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,"http://localhost:8081");

And I got the following error:

Exception in thread "main" io.confluent.common.config.ConfigException: Missing required configuration "schema.registry.url" which has no default value.
at io.confluent.common.config.ConfigDef.parse(ConfigDef.java:243)
at io.confluent.common.config.AbstractConfig.<init>(AbstractConfig.java:78)
at io.confluent.kafka.serializers.AbstractKafkaAvroSerDeConfig.<init>(AbstractKafkaAvroSerDeConfig.java:100)
at io.confluent.kafka.serializers.KafkaAvroSerializerConfig.<init>(KafkaAvroSerializerConfig.java:32)
at io.confluent.kafka.serializers.KafkaAvroSerializer.configure(KafkaAvroSerializer.java:48)
at io.confluent.kafka.streams.serdes.avro.SpecificAvroSerializer.configure(SpecificAvroSerializer.java:58)
at io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde.configure(SpecificAvroSerde.java:107)

I have tried to replace the line

config.put(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,"http://localhost:8081");

with

config.put("schema.registry.url","http://localhost:8081");

but with the same error

I have followed the instruction from this url when preparing my Stream application.

Any suggestion?

Answer

If you have keys and values in Avro format the following lines should do the trick for you,

config.put("key.converter.schema.registry.url", "http://localhost:8081");  
config.put("value.converter.schema.registry.url", "http://localhost:8081");

If this doesn’t seem to work you can override Serdes explicitly. For example, if you have Avro keys:

final Map<String, String> serdeConfig = Collections.singletonMap("schema.registry.url",
                                                                 "http://localhost:8081");
final Serde<GenericRecord> keyGenericAvroSerde = new GenericAvroSerde();
keyGenericAvroSerde.configure(serdeConfig, true); // true for record keys
final Serde<GenericRecord> valueGenericAvroSerde = new GenericAvroSerde();
valueGenericAvroSerde.configure(serdeConfig, false); // false for record values

StreamsBuilder builder = new StreamsBuilder();
KStream<GenericRecord, GenericRecord> textLines =
builder.stream(keyGenericAvroSerde, valueGenericAvroSerde, "my-avro-topic");
// Do whatever you like