[英]If Kafka Consumer fails (Spark Job), how to fetch the last offset committed by Kafka Consumer. (Scala)
[英]Spark job fails while filtering kafka messages
需要通过检查消息是否需要字段来检查发送到Kafka
事件消息是否有效,如果是,则将数据推送到Elasticsearch
。 这就是我做的方式:
object App {
val parseJsonStream = (inStream: RDD[String]) => {
inStream.flatMap(json => {
try {
val parsed = parse(json)
Option(parsed)
} catch {
case e: Exception => System.err.println("Exception while parsing JSON: " + json)
e.printStackTrace()
None
}
}).flatMap(v => {
if (v.values.isInstanceOf[List[Map[String, Map[String, Any]]]])
v.values.asInstanceOf[List[Map[String, Map[String, Any]]]]
else if (v.values.isInstanceOf[Map[String, Map[String, Any]]])
List(v.values.asInstanceOf[Map[String, Map[String, Any]]])
else {
System.err.println("EVENT WRONG FORMAT: " + v.values)
List()
}
}).flatMap(mapa => {
val h = mapa.get("header")
val b = mapa.get("body")
if (h.toSeq.toString.contains("session.end") && !b.toSeq.toString.contains("duration")) {
System.err.println("session.end HAS NO DURATION FIELD!")
None
}
else if (h.isEmpty || h.get.get("userID").isEmpty || h.get.get("timestamp").isEmpty) {
throw new Exception("FIELD IS MISSING")
None
}
else {
Some(mapa)
}
})
}
val kafkaStream: InputDStream[ConsumerRecord[String, String]] = KafkaUtils.createDirectStream[String, String](
ssc, PreferBrokers, Subscribe[String, String](KAFKA_EVENT_TOPICS, kafkaParams)
)
val kafkaStreamParsed = kafkaStream.transform(rdd => {
val eventJSON = rdd.map(_.value)
parseJsonStream(eventJSON)
}
)
val esEventsStream = kafkaStreamParsed.map(addElasticMetadata(_))
try {
EsSparkStreaming.saveToEs(esEventsStream, ELASTICSEARCH_EVENTS_INDEX + "_{postfix}" + "/" + ELASTICSEARCH_TYPE, Map("es.mapping.id" -> "docid")
)
} catch {
case e: Exception =>
EsSparkStreaming.saveToEs(esEventsStream, ELASTICSEARCH_FAILED_EVENTS)
e.printStackTrace()
}
}
我猜有人正在发送无效事件(这就是我为什么要进行此检查的原因),但是Spark job
没有跳过消息,它失败并显示消息:
用户类引发异常:org.apache.spark.SparkException:作业因阶段失败而中止:阶段6.0中的任务2失败4次,最近失败:阶段6.0中丢失任务2.3(TID 190,xxx.xxx.host.xx ,executor 3):java.lang.Exception:FIELD IS MISSING
我怎样才能防止它崩溃而只是跳过消息呢? 它是YARN
应用程序,使用:
Spark 2.3.1
Spark-streaming-kafka-0-10_2.11:2.3.1
Scala 2.11.8
而不是这个
throw new Exception("FIELD IS MISSING")
None
就这样做吧
None
抛出此异常会导致程序终止。
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