Question

我有两个卡夫卡主题my_priorized_topic和my_not_so_priorized_topic。我想在EventProcessor.doLogic上使用互斥锁，并始终优先处理来自my_prioritized_topic的消息之前来自my_not_so_prioritized_topic的句柄消息

有人可以给我一些指导，如何用Kotlin（也许是协程）解决这个问题吗？

class EventProcessor {
  fun doLogic(message: String) {
    ... // code which cannot be parallelized
  }
}

class KafkaConsumers(private val eventProcessor: EventProcessor) {
  @KafkaConsumer(topic = "my_priorized_topic")
  fun consumeFromPriorizedTopic(message: String) {
    eventProcessor.doLogic(message)
  }

  @KafkaConsumer(topic = "my_not_so_priorized_topic")
  fun consumeFromNotSoPrioritizedTopic(message: String) {
    eventProcessor.doLogic(message)  
  }
}

Answer 1

您可以为高优先级任务和低优先级任务创建两个Channel。然后，要使用通道中的事件，请使用协程的select表达式，然后将高优先级任务通道放在首位。

示例（字符串是偶数）：

fun process(value: String) {
    // do what you want with the event
}

suspend fun selectFromHighAndLow(highPriorityChannel: ReceiveChannel<String>, lowPriorityChannel: ReceiveChannel<String>): String =
        select<String> {
            highPriorityChannel.onReceive { value ->
                value
            }
            lowPriorityChannel.onReceive { value ->
                value
            }
        }


val highPriorityChannel = Channel<String>()
val lowPriorityChannel = Channel<String>()
while (true) {
    process(selectFromHighAndLow(highPriorityChannel, lowPriorityChannel))
}

要将内容发送到这些频道，可以使用channel.send(event)。

如何在Kotlin中的方法上实现互斥并在一个线程之前优先处理另一个线程？

1 个答案: