Flink-測試用的fake溫度感測器

Flink中，測試時，會用到自定義的source。

下為一例。。 該例使用溫度感測器的格式演示fake日誌數據源。

代碼用Scala寫的。

感測器...

• 感測器 - 樣例類

  SensorReads.scala：

        ​x         1

  package sr

  2

  ​

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  /**

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   * 

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   */

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  case class SensorReads(id:String,

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                         timestap:Long,

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                         tempture:Double)

     

• 感測器 - 數據源模擬

  SnsorSrc_4096T.scala：

        46         1

  package sr

  2

  ​

  3

  import org.apache.flink.streaming.api.functions.source.SourceFunction

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  import scala.util.Random

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  ​

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  /**

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   * period, is 4096 millis.

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   */

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  case class SnsorSrc_4096T extends SourceFunction[SensorReads] {

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      var isInRunning: Boolean = true

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      ////

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      override def run(sourceContext: SourceFunction.SourceContext[

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              SensorReads]): Unit = {

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          val rand: Random = new Random

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          var tptNow4 =

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              (1 to 4).map(

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                  "snsor_" + _.toString -> (23 + 16 * rand.nextGaussian))

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  ​

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          while (isInRunning) {

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              tptNow4 = tptNow4.map(

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                  t => t._1 -> (t._2 + rand.nextGaussian))

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              val timeStampNow: Long = System.currentTimeMillis

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              tptNow4.foreach{

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                  t =>

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                      sourceContext.collect( // O.U.T

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                          SensorReads(t._1, timeStampNow, t._2) )

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                  Thread.sleep(512)  }

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              //not set, is stm

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              Thread.sleep(2048)  }

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      }

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      override def cancel(): Unit = isInRunning = false

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  }

     

測試

SnsrSrcAappli.scala：

package applis

​

import org.apache.flink.streaming.api.scala._

import sr._

​

object SnsrSrcAappli extends App{

    val env = StreamExecutionEnvironment.getExecutionEnvironment

    env.addSource(SnsorSrc_4096T() )

                    .print("aaa")

    env.execute()

}

數據源模擬用case-class，此處使用則可以不寫new。

輸出

IDEA控制臺上run：

log4j:WARN No appenders could be found for logger (org.apache.flink.api.scala.ClosureCleaner$).

log4j:WARN Please initialize the log4j system properly.

log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

aaa:3> SensorReads(snsor_1,1573556705508,30.383394411578916)

aaa:4> SensorReads(snsor_2,1573556705508,21.397405872448672)

aaa:5> SensorReads(snsor_3,1573556705508,20.598086139457727)

aaa:6> SensorReads(snsor_4,1573556705508,18.30066983735531)

aaa:7> SensorReads(snsor_1,1573556709627,30.120955223032546)

aaa:8> SensorReads(snsor_2,1573556709627,22.38746867201145)

aaa:1> SensorReads(snsor_3,1573556709627,20.45357507067989)

aaa:2> SensorReads(snsor_4,1573556709627,17.18467261133715)

aaa:3> SensorReads(snsor_1,1573556713729,31.686487593592904)

aaa:4> SensorReads(snsor_2,1573556713729,20.67106361911623)

aaa:5> SensorReads(snsor_3,1573556713729,21.27724215221553)

aaa:6> SensorReads(snsor_4,1573556713729,16.84273306583804)

​

Process finished with exit code -1

...

如果SnsorSrc_4096T.scala中，「當前溫度」.foreach這樣寫：

tptNow4.foreach{

    t =>

        sourceContext.collect( // O.U.T

            SensorReads(t._1, System.currentTimeMillis, t._2) )

    Thread.sleep(512)  }

那麼結果就會是：

log4j:WARN No appenders could be found for logger (org.apache.flink.api.scala.ClosureCleaner$).

log4j:WARN Please initialize the log4j system properly.

log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

aaa:5> SensorReads(snsor_1,1573561932216,20.427373784204445)