使用ktor和kotlin对kafka消费者进行na抽象

我正在为消费者和制作人卡夫卡创建一个抽象，以避免代码一直重复。因此，我使用kotlin和gradle创建了一个名为kafka commons的库，并输入以下代码： 卡夫卡制作人：

fun producer(
    bootstrapServers: String,
    idempotence: Boolean,
    acks: Acks,
    retries: Int,
    requestPerConnection: Int,
    compression: Compression,
    linger: Int,
    batchSize: BatchSize
): KafkaProducer<String, Any> {
    val prop: HashMap<String, Any> = HashMap()
    prop[BOOTSTRAP_SERVERS_CONFIG] = bootstrapServers
    prop[KEY_SERIALIZER_CLASS_CONFIG] = StringSerializer::class.java.name
    prop[VALUE_SERIALIZER_CLASS_CONFIG] = StringSerializer::class.java.name
    prop[ENABLE_IDEMPOTENCE_CONFIG] = idempotence
    prop[ACKS_CONFIG] = acks.value
    prop[RETRIES_CONFIG] = retries
    prop[MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION] = requestPerConnection
    prop[COMPRESSION_TYPE_CONFIG] = compression.value
    prop[LINGER_MS_CONFIG] = linger
    prop[BATCH_SIZE_CONFIG] = batchSize.value

    return KafkaProducer(prop)
}

suspend inline fun <reified K : Any, reified V : Any> KafkaProducer<K, V>.dispatch(record: ProducerRecord<K, V>) =
    suspendCoroutine<RecordMetadata> { continuation ->
        val callback = Callback { metadata, exception ->
            if (metadata == null) {
                continuation.resumeWithException(exception!!)
            } else {
                continuation.resume(metadata)
            }
        }
        this.send(record, callback)
    }

id：创建一个唯一的id 状态：消息状态可以是：打开/处理/关闭/错误 消息：来自http请求的对象，例如：If have a Post

例如：如果有插入用户：带正文的帖子：

{id:1，姓名：约翰，姓氏：维克}

所以消息将是这个对象，依此类推

为了创建这个命令，我做了这个函数：

suspend fun creatCommand(
    topicName: String,
    id: UUID,
    commandStatus: CommandStatus,
    request: Any,
    bootstrapServers: String,
    idempotence: Boolean,
    acks: Acks,
    retries: Int,
    requestPerConnection: Int,
    compression: Compression,
    linger: Int,
    batchSize: BatchSize
): Unit {
    val producer = producer(
        bootstrapServers,
        idempotence,
        acks,
        retries,
        requestPerConnection,
        compression,
        linger,
        batchSize)

    val command = toCommand(processStarted(id, commandStatus, request))
    val record = ProducerRecord<String, Any>(topicName, id.toString(), command)
    coroutineScope { launch { producer.dispatch(record) } }
}

---

有人可以帮我吗？

如果我理解正确，您在将JSON映射到对象时遇到了问题

   val mapper = ObjectMaper
   while (true) {
        val records = consumer.poll(Duration.ofMillis(100))
        for (record in records) {
            val cmd = mapper.readvalue(record.value(), command::class.java)
            // do things with cmd
        }
    }

注意：Kafka有自己的JSON到POJO反序列化程序，如果您想将数据发送到数据库，Kafka Connect通常比简单的消费循环更具容错性

fun Route.user(service: Service) =
    route("/api/access") {
        post("/test") {
            call.respond(service.command(call.receive())) 
            }
}

>>>>>> other class <<<<<<<<

classService () {
    fun command( all parameters) { creatCommand(all parameters)} 
}

fun consumer(
    bootstrapServers: String,
    group: String,
    autoCommit: Boolean,
    offsetBehaviour: OffsetBehaviour,
    pollMax: Int
): KafkaConsumer<String, Any> {
    val prop: HashMap<String, Any> = HashMap()
    prop[BOOTSTRAP_SERVERS_CONFIG] = bootstrapServers
    prop[KEY_DESERIALIZER_CLASS_CONFIG] = StringDeserializer::class.java.name
    prop[VALUE_DESERIALIZER_CLASS_CONFIG] = StringDeserializer::class.java.name
    prop[GROUP_ID_CONFIG] = group
    prop[AUTO_OFFSET_RESET_CONFIG] = offsetBehaviour
    prop[ENABLE_AUTO_COMMIT_CONFIG] = autoCommit
    prop[MAX_POLL_RECORDS_CONFIG] = pollMax

    return KafkaConsumer(prop)
}

fun<T> recordingCommand(
    command: Class<T>,
    topic: String,
    bootstrapServers: String,
    group: String,
    autoCommit: Boolean,
    offsetBehaviour: OffsetBehaviour,
    pollMax: Int
) {
    val consumer = consumer(bootstrapServers, group, autoCommit, offsetBehaviour, pollMax)
    consumer.subscribe(mutableListOf(topic))
    while (true) {
        val records = consumer.poll(Duration.ofMillis(100))
        for (record in records) {
            val om = ObjectMaper
            om.readvalue(record.value(), command::class.java)

            >>>> I GOT LOST HERE <<<<<<

        }
    }
}

service.insert(recordingCommand(all parameters)).

   val mapper = ObjectMaper
   while (true) {
        val records = consumer.poll(Duration.ofMillis(100))
        for (record in records) {
            val cmd = mapper.readvalue(record.value(), command::class.java)
            // do things with cmd
        }
    }