如何知道火花流窗口中的 RDD 是否已完成火花作业?

Question

我正在Spark Streaming应用程序中读取来自Kafka的消息。

火花批处理持续时间：15秒 火花窗口：60秒

var dstream = KafkaUtils.createDirectStream() // ignore the argumtns
var windowedStream = dstream.window(SparkWindow)
// delete data from REDIS
windowedStream.foreachRDD(rdd -> {
if(!rdd.isEmpty()) {
JavaFutureAction<Void> v = rdd.foreachPartitionAsync(t -> {
// collect error data across partitions and write those to REDIS
})// foreachPartitionAsync ends
}
})
// fetchFromREDISAndProcess() --Once foreachRDD ends. fetch error data from REDIS and process them

有一个限制，我必须首先在 spark 窗口中从每个分区和 RDD 收集错误记录，然后在驱动程序上处理它们。

我将在每个Spark窗口中获得4个RDD。

问题： 我想在每个窗口后从 REDIS 读取数据并在继续下一个窗口之前处理它们。有没有办法确保每次火花窗口结束时都执行我的代码？

Answer 1

您可以使用以下逻辑：：：

var dstream = KafkaUtils.createDirectStream() // ignore the argumtns
var windowedStream = dstream.window(SparkWindow)
// delete data from REDIS
var partitions = 4;
var currentPart = 0;
windowedStream.foreachRDD(rdd -> {
if(!rdd.isEmpty()) {
JavaFutureAction<Void> v = rdd.foreachPartitionAsync(t -> {
// collect error data across partitions and write those to REDIS
})// foreachPartitionAsync ends
if(++currentPart % partitions == 0)    //It will be true at every 4th RDD where window will end.
//Read data from REDIS and process here as after this new window will start.
}
})
// fetchFromREDISAndProcess() --Once foreachRDD ends. fetch error data from REDIS and process them