Test Kafka Protobuf Events

Context

• You need a Schema Registry of version 5.5.0+ to have the support of Protobuf. (it's already correctly setup the docker-compose file)
• I use the lib https://github.com/sbt/sbt-protobuf to generate classes from Protobuf schemas.
• A good doc is available here : https://docs.confluent.io/current/schema-registry/serdes-develop/serdes-protobuf.html

How to clone (really ?)

git clone git@github.com:PLarboulette/kafka-protobuf-events.git

How to use

• Add protobuf schemas into the protobuf folder of each project (consumer and producer). Your file need an extension .proto and to be located in this folder. I think you can customize this but why ?
• Use sbt protobufGenerate.
• Your new model(s) will be available into {{messageName}}OuterClass.{{messageName : for example, I define a model Animal, so the model I use with Scala is AnimalOuterClass.Animal.
• Launch the environment : docker-compose -f docker-compose.yml up
• Run the consumer
• Run the producer. You can change the name of the animal to see the difference between the records in the topic.

Some command lines

• To see the available subjects in the Schema Registry, you can use : curl http://localhost:8081/subjects
• To see the details about the schema, you can use curl http://localhost:8081/subjects/{{yourSchemaReturnedByThePreviousCall}}/versions/1 (change the version if you have made an evolution) You have a return like this :

{
    subject: "animal-topic-value",
    version: 1,
    id: 1,
    schemaType: "PROTOBUF",
    schema: "syntax = "proto3"; message Dog { int32 paws = 1; } message Bird { int32 wings = 1; } message Animal { string name = 1; int32 age = 2; oneof animal { .Dog dog = 3; .Bird bird = 4; } } "
}