How to dockerize and write a dockerfile a Scala written kafka producer - scala

Question

I am new to dockers and been trying to understand how to write a docker file to create my custom image. My Scala class is producing message to a topic continuously. I want to reproduce the same functionality with dockers. Can someone help me with the docker file.
I have tried using sbt docker:publishLocal, it creates the image but when i try to run the image it says unble to find the class. I am specifically looking to run it using docker file.
Here is the code which is working in intelliJ
import java.util.Properties
import org.apache.kafka.clients.producer._
object Scala_producer extends App{
val props = new Properties()
props.put("bootstrap.servers", "localhost:9092")
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer")
val producer = new KafkaProducer[String, String](props)
val TOPIC="tt"
println(producer.partitionsFor(TOPIC))
while(true){
val record = new ProducerRecord(TOPIC, "key", "hello ")
producer.send(record)
println("producing")
}
producer.close()
}
i expect to run the docker and get infinite producing message.

Answer 1

If this is the only issue, then add the mainclass to your build.sbt:
mainClass in Compile := Some("com.example.Scala_producer")