Extract the time stamp from kafka messages in spark streaming?

问题

Trying to read from kafka source. I want to extract timestamp from message received to do structured spark streaming. kafka(version 0.10.0.0) spark streaming(version 2.0.1)

回答1:

I'd suggest couple things:

Suppose you create a stream via latest Kafka Streaming Api (0.10 Kafka)

E.g. you use dependency: "org.apache.spark" %% "spark-streaming-kafka-0-10" % 2.0.1

Than you create a stream, according to the docs above:

 val kafkaParams = Map[String, Object](
     "bootstrap.servers" -> "broker1:9092,broker2:9092",
     "key.deserializer" -> classOf[StringDeserializer],
     "value.deserializer" -> classOf[ByteArrayDeserializer],
     "group.id" -> "spark-streaming-test",
     "auto.offset.reset" -> "latest",
     "enable.auto.commit" -> (false: java.lang.Boolean))

val sparkConf = new SparkConf()
// suppose you have 60 second window
val ssc = new StreamingContext(sparkConf, Seconds(60))
ssc.checkpoint("checkpoint")

val stream = KafkaUtils.createDirectStream(ssc, PreferConsistent,
Subscribe[String, Array[Byte]](topics, kafkaParams))

Your stream will be an DStream of ConsumerRecord[String,Array[Byte]] and you can get a timestamp and key-value as simple as:
```
stream.map { record => (record.timestamp(), record.key(), record.value())  }
```

Hope that helps.

回答2:

spark.read
  .format("kafka")
  .option("kafka.bootstrap.servers", "your.server.com:9092")
  .option("subscribe", "your-topic")
  .load()
  .select($"timestamp", $"value")

Field "timestamp" is what you are looking for. Type - java.sql.Timestamp. Make sure that you are connecting to 0.10 Kafka server. There is no timestamp in earlier versions. Full list of fields described here - http://spark.apache.org/docs/latest/structured-streaming-kafka-integration.html#creating-a-kafka-source-for-batch-queries

来源：https://stackoverflow.com/questions/40586663/extract-the-time-stamp-from-kafka-messages-in-spark-streaming

标签

apache-kafka

spark-streaming

spark-streaming-kafka