[SPARK-21334][CORE] Add metrics reporting service to External Shuffle Server

core/src/main/scala/org/apache/spark/deploy/ExternalShuffleService.scala

@@ -17,7 +17,7 @@
 
 package org.apache.spark.deploy
 
-import java.util.concurrent.CountDownLatch
+import java.util.concurrent.{CountDownLatch, TimeUnit}
 
 import scala.collection.JavaConverters._
 
@@ -30,7 +30,33 @@ import org.apache.spark.network.netty.SparkTransportConf
 import org.apache.spark.network.server.{TransportServer, TransportServerBootstrap}
 import org.apache.spark.network.shuffle.ExternalShuffleBlockHandler
 import org.apache.spark.network.util.TransportConf
-import org.apache.spark.util.{ShutdownHookManager, Utils}
+import org.apache.spark.util.{ShutdownHookManager, ThreadUtils, Utils}
+
+
+private
+class MetricReportingService(metricsSystem: MetricsSystem,
+                           reportingIntervalInSeconds: Int)
+  extends Runnable with Logging {
+
+  private val threadPool = ThreadUtils
+    .newDaemonSingleThreadScheduledExecutor("metrics-reporter")
+
+  override def run(): Unit = {
+    metricsSystem.report()
+  }
+
+  def start() : Unit = {
+    logInfo("Starting a metric reporting service. Interval="
+      + reportingIntervalInSeconds + "s")
+    threadPool.scheduleAtFixedRate(this,
+      reportingIntervalInSeconds, reportingIntervalInSeconds, TimeUnit.SECONDS)
+  }
+
+  def stop() : Unit = {
+    threadPool.shutdownNow()
+  }
+}
+
 
 /**
  * Provides a server from which Executors can read shuffle files (rather than reading directly from
@@ -45,6 +71,9 @@ class ExternalShuffleService(sparkConf: SparkConf, securityManager: SecurityMana
   protected val masterMetricsSystem =
     MetricsSystem.createMetricsSystem("shuffleService", sparkConf, securityManager)
 
+  private val metricReportingService = new MetricReportingService(masterMetricsSystem,
+    sparkConf.getInt("spark.shuffle.ess.metricReportingInterval", 10))
+
   private val enabled = sparkConf.getBoolean("spark.shuffle.service.enabled", false)
   private val port = sparkConf.getInt("spark.shuffle.service.port", 7337)
 
@@ -85,6 +114,8 @@ class ExternalShuffleService(sparkConf: SparkConf, securityManager: SecurityMana
 
     masterMetricsSystem.registerSource(shuffleServiceSource)
     masterMetricsSystem.start()
+    // Start the metrics reporting service
+    metricReportingService.start()
   }
 
   /** Clean up all shuffle files associated with an application that has exited. */
@@ -97,6 +128,8 @@ class ExternalShuffleService(sparkConf: SparkConf, securityManager: SecurityMana
       server.close()
       server = null
     }
+    metricReportingService.stop()
+    masterMetricsSystem.stop()
   }
 }