I would like to log to Kafka if I can reach a broker, but simply skip it if Kafka is not available. To that end, I’d like to set the Boolean variable useKafka but I can’t find an elegant way of doing this.

Below is my attempt.

...
      val props = new Properties()
      props.put("bootstrap.servers", kafkaBroker)
      props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
      props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer")
      props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
      props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
      props.put("request.timeout.ms", 200);

      var useKafka: Boolean = true

      // This is kludgy
      val producer = try {
        new KafkaProducer[String, String](props)
      }
      catch {
        useKafka = false
      }

...

Results in the following error at compile time: value isDefinedAt is not a member of Unit

Here is how I intend to use the Boolean in the code:

if (useKafka) producer.send(new ProducerRecord[String, String](kafkaTopic, "cobol", logStr))

Based on Dima’s answer, I changed my code as follows.

A KafkaConsumer throws an error and is better for testing. By using a Future with a timeout, I can wait for a reasonable amount of time.

      val simpleConsumer = new org.apache.kafka.clients.consumer.KafkaConsumer[String, String](props)
      val testKafka = Try {Await.ready(Future(simpleConsumer.listTopics), 200  milliseconds)}.toOption

useKafka = testKafka.nonEmpty