Message value in Confluent Cloud not decoding properly

Question

I'm very new to kafka and confluent. I wrote a Producer nearly identical to the tutorial on https://www.confluent.fr/blog/schema-registry-avro-in-spring-boot-application-tutorial/ with my own dummy model. The application.yaml is the same as well. When I send the message to ccloud - the messages being received is gibberish

Any idea as to how to fix this? When I do a System.out.println of the avro POJO before sending to kafka, the object looks good with all the proper values.

{
  "locationId": 1, 
  "time": 1575950400, 
  "temperature": 9.45, 
  "summary": "Overcast", 
  "icon": "cloudy", 
  "precipitationProbability": 0.24,
  ...

Whereas when I download the message from ccloud, the value looks like this

[ 
 {
   "topic":"Weather",
   "partition":0,
   "offset":14,
   "timestamp":1576008230509,
   "timestampType":"CREATE_TIME",
   "headers":[],
   "key":"dummyKey",
   "value":"\u0000\u0000\u0001��\u0002\u0002����\u000b\u0002fffff�\"@\
   ...
}

Answer 1

You're actually doing everything right :) What you're hitting is just a current limitation in the Confluent Cloud GUI in rendering Avro messages.

If you consume the message as Avro you'll see that everything is fine. Here's an example of consuming the message from Confluent Cloud using kafkacat:

$ source .env
$ docker run --rm edenhill/kafkacat:1.5.0 \
          -X security.protocol=SASL_SSL -X sasl.mechanisms=PLAIN \
          -X ssl.ca.location=./etc/ssl/cert.pem -X api.version.request=true \
          -b ${CCLOUD_BROKER_HOST}:9092 \
          -X sasl.username="${CCLOUD_API_KEY}" \
          -X sasl.password="${CCLOUD_API_SECRET}" \
          -r https://"${CCLOUD_SCHEMA_REGISTRY_API_KEY}":"${CCLOUD_SCHEMA_REGISTRY_API_SECRET}"@${CCLOUD_SCHEMA_REGISTRY_HOST} \
          -s avro \
          -t mssql-04-mssql.dbo.ORDERS \
          -f '"'"'Topic %t[%p], offset: %o (Time: %T)\nHeaders: %h\nKey: %k\nPayload (%S bytes): %s\n'"'"' \
          -C -o beginning -c1


Topic mssql-04-mssql.dbo.ORDERS[2], offset: 110 (Time: 1576056196725)
Headers:
Key:
Payload (53 bytes): {"order_id": {"int": 1345}, "customer_id": {"int": 11}, "order_ts": {"int": 18244}, "order_total_usd": {"double": 2.4399999999999999}, "item": {"string": "Bread - Corn Muffaleta Onion"}}

This is the same topic shown here, with the binary Avro value field: