MetricsSystem refactor

11 files changed, 193 insertions, 149 deletions

diff --git a/core/src/main/scala/spark/deploy/master/Master.scala b/core/src/main/scala/spark/deploy/master/Master.scala
index 3a7c4e5a52..e44f5e3168 100644
--- a/core/src/main/scala/spark/deploy/master/Master.scala
+++ b/core/src/main/scala/spark/deploy/master/Master.scala
@@ -29,12 +29,12 @@ import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet}
 
 import spark.deploy._
 import spark.{Logging, SparkException, Utils}
+import spark.metrics.MetricsSystem
 import spark.util.AkkaUtils
 import ui.MasterWebUI
 
 
-private[spark] class Master(host: String, port: Int, webUiPort: Int) extends Actor 
-with Logging with MasterInstrumentation {
+private[spark] class Master(host: String, port: Int, webUiPort: Int) extends Actor with Logging {
   val DATE_FORMAT = new SimpleDateFormat("yyyyMMddHHmmss")  // For application IDs
   val WORKER_TIMEOUT = System.getProperty("spark.worker.timeout", "60").toLong * 1000
 
@@ -57,6 +57,8 @@ with Logging with MasterInstrumentation {
   val webUi = new MasterWebUI(self, webUiPort)
 
   Utils.checkHost(host, "Expected hostname")
+  
+  val masterInstrumentation = new MasterInstrumentation(this)
 
   val masterPublicAddress = {
     val envVar = System.getenv("SPARK_PUBLIC_DNS")
@@ -75,7 +77,7 @@ with Logging with MasterInstrumentation {
     webUi.start()
     context.system.scheduler.schedule(0 millis, WORKER_TIMEOUT millis)(timeOutDeadWorkers())
     
-    initialize(this)
+    Master.metricsSystem.registerSource(masterInstrumentation)
   }
 
   override def postStop() {
@@ -319,21 +321,22 @@ with Logging with MasterInstrumentation {
       removeWorker(worker)
     }
   }
-  
-  override def postStop() {
-    uninitialize()
-  }
 }
 
 private[spark] object Master {
   private val systemName = "sparkMaster"
   private val actorName = "Master"
   private val sparkUrlRegex = "spark://([^:]+):([0-9]+)".r
+  
+  private val metricsSystem = MetricsSystem.createMetricsSystem("master")
 
   def main(argStrings: Array[String]) {
     val args = new MasterArguments(argStrings)
     val (actorSystem, _) = startSystemAndActor(args.host, args.port, args.webUiPort)
+    
+    metricsSystem.start()
     actorSystem.awaitTermination()
+    metricsSystem.stop()
   }
 
   /** Returns an `akka://...` URL for the Master actor given a sparkUrl `spark://host:ip`. */
diff --git a/core/src/main/scala/spark/deploy/master/MasterInstrumentation.scala b/core/src/main/scala/spark/deploy/master/MasterInstrumentation.scala
index c295e725d7..5ea9a90319 100644
--- a/core/src/main/scala/spark/deploy/master/MasterInstrumentation.scala
+++ b/core/src/main/scala/spark/deploy/master/MasterInstrumentation.scala
@@ -1,47 +1,35 @@
 package spark.deploy.master
 
-import com.codahale.metrics.{Gauge, JmxReporter, MetricRegistry}
+import java.util.{Map, HashMap => JHashMap} 
 
-import spark.metrics.AbstractInstrumentation
+import com.codahale.metrics.{Gauge, Metric}
 
-private[spark] trait MasterInstrumentation extends AbstractInstrumentation {
-  var masterInst: Option[Master] = None
-  val metricRegistry = new MetricRegistry()
-  
-  override def registryHandler = metricRegistry
-  
-  override def instance = "master"
+import spark.metrics.source.Source
+
+private[spark] class MasterInstrumentation(val master: Master) extends Source {
+  val className = classOf[Master].getName()
+  val instrumentationName = "master"
+    
+  override def sourceName = instrumentationName
   
-  def initialize(master: Master) {
-    masterInst = Some(master)
+  override def getMetrics(): Map[String, Metric] = {
+    val gauges = new JHashMap[String, Metric]
     
-    // Register all the sources
-    registerSources()
+    // Gauge for worker numbers in cluster
+    gauges.put(className + ".workers.number", new Gauge[Int] {
+      override def getValue: Int = master.workers.size
+    })
     
-    // Register and start all the sinks
-    registerSinks()
-  }
-  
-  def uninitialize() {
-    unregisterSinks()
+    // Gauge for application numbers in cluster
+    gauges.put(className + ".apps.number", new Gauge[Int] {
+      override def getValue: Int = master.apps.size
+    })
+    
+    // Gauge for waiting application numbers in cluster
+    gauges.put(className + ".waiting_apps.number", new Gauge[Int] {
+      override def getValue: Int = master.waitingApps.size
+    })
+    
+    gauges
   }
-  
-  // Gauge for worker numbers in cluster
-  metricRegistry.register(MetricRegistry.name(classOf[Master], "workers", "number"), 
-  	new Gauge[Int] {
-      override def getValue: Int = masterInst.map(_.workers.size).getOrElse(0)
-  })
-  
-  // Gauge for application numbers in cluster
-  metricRegistry.register(MetricRegistry.name(classOf[Master], "apps", "number"),
-    new Gauge[Int] {
-	  override def getValue: Int = masterInst.map(_.apps.size).getOrElse(0)
-  })
-
-  // Gauge for waiting application numbers in cluster
-  metricRegistry.register(MetricRegistry.name(classOf[Master], "waiting_apps", "number"), 
-    new Gauge[Int] {
-      override def getValue: Int = masterInst.map(_.waitingApps.size).getOrElse(0)
-  })
-  
 }
\ No newline at end of file
diff --git a/core/src/main/scala/spark/deploy/worker/Worker.scala b/core/src/main/scala/spark/deploy/worker/Worker.scala
index b64bdb8d28..eaa1c1806f 100644
--- a/core/src/main/scala/spark/deploy/worker/Worker.scala
+++ b/core/src/main/scala/spark/deploy/worker/Worker.scala
@@ -23,6 +23,7 @@ import akka.util.duration._
 import spark.{Logging, Utils}
 import spark.util.AkkaUtils
 import spark.deploy._
+import spark.metrics.MetricsSystem
 import akka.remote.{RemoteClientLifeCycleEvent, RemoteClientShutdown, RemoteClientDisconnected}
 import java.text.SimpleDateFormat
 import java.util.Date
@@ -41,7 +42,7 @@ private[spark] class Worker(
     memory: Int,
     masterUrl: String,
     workDirPath: String = null)
-  extends Actor with Logging with WorkerInstrumentation {
+  extends Actor with Logging {
 
   Utils.checkHost(host, "Expected hostname")
   assert (port > 0)
@@ -67,6 +68,8 @@ private[spark] class Worker(
   var coresUsed = 0
   var memoryUsed = 0
 
+  val workerInstrumentation = new WorkerInstrumentation(this)
+
   def coresFree: Int = cores - coresUsed
   def memoryFree: Int = memory - memoryUsed
 
@@ -99,7 +102,8 @@ private[spark] class Worker(
     connectToMaster()
     startWebUi()
 
-    initialize(this)
+    Worker.metricsSystem.registerSource(workerInstrumentation)
+    Worker.metricsSystem.start()
   }
 
   def connectToMaster() {
@@ -182,11 +186,13 @@ private[spark] class Worker(
     executors.values.foreach(_.kill())
     webUi.stop()
 
-    uninitialize()
+    Worker.metricsSystem.stop()
   }
 }
 
 private[spark] object Worker {
+  private val metricsSystem = MetricsSystem.createMetricsSystem("worker")
+
   def main(argStrings: Array[String]) {
     val args = new WorkerArguments(argStrings)
     val (actorSystem, _) = startSystemAndActor(args.host, args.port, args.webUiPort, args.cores,
diff --git a/core/src/main/scala/spark/deploy/worker/WorkerInstrumentation.scala b/core/src/main/scala/spark/deploy/worker/WorkerInstrumentation.scala
index 2f725300b5..37fd154859 100644
--- a/core/src/main/scala/spark/deploy/worker/WorkerInstrumentation.scala
+++ b/core/src/main/scala/spark/deploy/worker/WorkerInstrumentation.scala
@@ -1,58 +1,89 @@
 package spark.deploy.worker
 
-import com.codahale.metrics.{JmxReporter, Gauge, MetricRegistry}
+import com.codahale.metrics.{Gauge, Metric}
 
-import spark.metrics.AbstractInstrumentation
+import java.util.{Map, HashMap => JHashMap}
 
-private[spark] trait WorkerInstrumentation extends AbstractInstrumentation {
-  var workerInst: Option[Worker] = None
-  val metricRegistry = new MetricRegistry()
-  
-  override def registryHandler = metricRegistry
-  
-  override def instance = "worker"
+import spark.metrics.source.Source
+
+private[spark] class WorkerInstrumentation(val worker: Worker) extends Source {
+  val className = classOf[Worker].getName()
   
-  def initialize(worker: Worker) {
-    workerInst = Some(worker)
+  override def sourceName = "worker"
     
-    // Register all the sources
-    registerSources()
+  override def getMetrics: Map[String, Metric] = {
+    val gauges = new JHashMap[String, Metric]
     
-    // Register and start all the sinks
-    registerSinks()
-  }
-  
-  def uninitialize() {
-    unregisterSinks()
+    // Gauge for executors number
+    gauges.put(className + ".executor.number", new Gauge[Int]{
+      override def getValue: Int = worker.executors.size
+    })
+    
+    gauges.put(className + ".core_used.number", new Gauge[Int]{
+      override def getValue: Int = worker.coresUsed
+    })
+    
+    gauges.put(className + ".mem_used.MBytes", new Gauge[Int]{
+      override def getValue: Int = worker.memoryUsed
+    })
+    
+    gauges.put(className + ".core_free.number", new Gauge[Int]{
+      override def getValue: Int = worker.coresFree
+    })
+    
+    gauges.put(className + ".mem_free.MBytes", new Gauge[Int]{
+      override def getValue: Int = worker.memoryFree
+    })
+    
+    gauges
   }
-  
-  // Gauge for executors number
-  metricRegistry.register(MetricRegistry.name(classOf[Worker], "executor", "number"), 
-    new Gauge[Int] {
-      override def getValue: Int = workerInst.map(_.executors.size).getOrElse(0)
-  })
-  
-  // Gauge for cores used of this worker
-  metricRegistry.register(MetricRegistry.name(classOf[Worker], "core_used", "number"), 
-    new Gauge[Int] {
-      override def getValue: Int = workerInst.map(_.coresUsed).getOrElse(0)
-  })
-  
-  // Gauge for memory used of this worker
-  metricRegistry.register(MetricRegistry.name(classOf[Worker], "mem_used", "MBytes"), 
-    new Gauge[Int] {
-      override def getValue: Int = workerInst.map(_.memoryUsed).getOrElse(0)
-  })
-  
-  // Gauge for cores free of this worker
-  metricRegistry.register(MetricRegistry.name(classOf[Worker], "core_free", "number"), 
-    new Gauge[Int] {
-      override def getValue: Int = workerInst.map(_.coresFree).getOrElse(0)
-  })
-  
-  // Gauge for memory used of this worker
-  metricRegistry.register(MetricRegistry.name(classOf[Worker], "mem_free", "MBytes"), 
-    new Gauge[Int] {
-      override def getValue: Int = workerInst.map(_.memoryFree).getOrElse(0)
-  })
-}
\ No newline at end of file
+}
+//private[spark] trait WorkerInstrumentation extends AbstractInstrumentation {
+//  var workerInst: Option[Worker] = None
+//  val metricRegistry = new MetricRegistry()
+//  
+//  override def registryHandler = metricRegistry
+//  
+//  override def instance = "worker"
+//  
+//  def initialize(worker: Worker) {
+//    workerInst = Some(worker)
+//
+//    registerSources()
+//    registerSinks()
+//  }
+//  
+//  def uninitialize() {
+//    unregisterSinks()
+//  }
+//  
+//  // Gauge for executors number
+//  metricRegistry.register(MetricRegistry.name(classOf[Worker], "executor", "number"), 
+//    new Gauge[Int] {
+//      override def getValue: Int = workerInst.map(_.executors.size).getOrElse(0)
+//  })
+//  
+//  // Gauge for cores used of this worker
+//  metricRegistry.register(MetricRegistry.name(classOf[Worker], "core_used", "number"), 
+//    new Gauge[Int] {
+//      override def getValue: Int = workerInst.map(_.coresUsed).getOrElse(0)
+//  })
+//  
+//  // Gauge for memory used of this worker
+//  metricRegistry.register(MetricRegistry.name(classOf[Worker], "mem_used", "MBytes"), 
+//    new Gauge[Int] {
+//      override def getValue: Int = workerInst.map(_.memoryUsed).getOrElse(0)
+//  })
+//  
+//  // Gauge for cores free of this worker
+//  metricRegistry.register(MetricRegistry.name(classOf[Worker], "core_free", "number"), 
+//    new Gauge[Int] {
+//      override def getValue: Int = workerInst.map(_.coresFree).getOrElse(0)
+//  })
+//  
+//  // Gauge for memory used of this worker
+//  metricRegistry.register(MetricRegistry.name(classOf[Worker], "mem_free", "MBytes"), 
+//    new Gauge[Int] {
+//      override def getValue: Int = workerInst.map(_.memoryFree).getOrElse(0)
+//  })
+//}
\ No newline at end of file
diff --git a/core/src/main/scala/spark/metrics/AbstractInstrumentation.scala b/core/src/main/scala/spark/metrics/MetricsSystem.scala
index 9cae1e0220..ea1bc490b5 100644
--- a/core/src/main/scala/spark/metrics/AbstractInstrumentation.scala
+++ b/core/src/main/scala/spark/metrics/MetricsSystem.scala
@@ -2,7 +2,7 @@ package spark.metrics
 
 import scala.collection.mutable
 
-import com.codahale.metrics.{JmxReporter, MetricRegistry}
+import com.codahale.metrics.{JmxReporter, MetricSet, MetricRegistry}
 
 import java.util.Properties
 import java.util.concurrent.TimeUnit
@@ -11,70 +11,76 @@ import spark.Logging
 import spark.metrics.sink._
 import spark.metrics.source._
 
-private [spark] trait AbstractInstrumentation extends Logging {
+private[spark] class MetricsSystem private (val instance: String) extends Logging {
   initLogging()
   
-  // Get MetricRegistry handler
-  def registryHandler: MetricRegistry
-  // Get the instance name
-  def instance: String
-  
   val confFile = System.getProperty("spark.metrics.conf.file", MetricsConfig.DEFAULT_CONFIG_FILE)
   val metricsConfig = new MetricsConfig(confFile)
   
   val sinks = new mutable.ArrayBuffer[Sink]
   val sources = new mutable.ArrayBuffer[Source]
   
+  def start() {
+    registerSources()
+    registerSinks()
+  }
+   
+  def stop() {
+    sinks.foreach(_.stop)
+  }
+  
+  def registerSource(source: Source) {
+    sources += source
+    MetricsSystem.registry.registerAll(source.asInstanceOf[MetricSet])
+  }
+  
   def registerSources() {
     val instConfig = metricsConfig.getInstance(instance)
-    val sourceConfigs = MetricsConfig.subProperties(instConfig, AbstractInstrumentation.SOURCE_REGEX)
+    val sourceConfigs = MetricsConfig.subProperties(instConfig, MetricsSystem.SOURCE_REGEX)
     
-    // Register all the sources
+    // Register all the sources related to instance
     sourceConfigs.foreach { kv =>
       val classPath = kv._2.getProperty("class")
       try {
-        val source = Class.forName(classPath).getConstructor(classOf[MetricRegistry])
-          .newInstance(registryHandler)
+        val source = Class.forName(classPath).newInstance()
         sources += source.asInstanceOf[Source]
+        MetricsSystem.registry.registerAll(source.asInstanceOf[MetricSet])
       } catch {
         case e: Exception => logError("source class " + classPath + " cannot be instantialized", e)
       }
     }
-    sources.foreach(_.registerSource)
   }
   
   def registerSinks() {
     val instConfig = metricsConfig.getInstance(instance)
-    val sinkConfigs = MetricsConfig.subProperties(instConfig, AbstractInstrumentation.SINK_REGEX)
+    val sinkConfigs = MetricsConfig.subProperties(instConfig, MetricsSystem.SINK_REGEX)
     
     // Register JMX sink as a default sink
-    sinks += new JmxSink(registryHandler)
+    sinks += new JmxSink(MetricsSystem.registry)
     
     // Register other sinks according to conf
     sinkConfigs.foreach { kv =>
-      val classPath = if (AbstractInstrumentation.DEFAULT_SINKS.contains(kv._1)) {
-        AbstractInstrumentation.DEFAULT_SINKS(kv._1)
+      val classPath = if (MetricsSystem.DEFAULT_SINKS.contains(kv._1)) {
+        MetricsSystem.DEFAULT_SINKS(kv._1)
       } else {
         // For non-default sink, a property class should be set and create using reflection
         kv._2.getProperty("class")
       }
       try {
         val sink = Class.forName(classPath).getConstructor(classOf[Properties], classOf[MetricRegistry])
-          .newInstance(kv._2, registryHandler)
+          .newInstance(kv._2, MetricsSystem.registry)
         sinks += sink.asInstanceOf[Sink]
       } catch {
         case e: Exception => logError("sink class " + classPath + " cannot be instantialized", e)
       }
     }
-    sinks.foreach(_.registerSink)
-  }
-  
-  def unregisterSinks() {
-    sinks.foreach(_.unregisterSink)
+    sinks.foreach(_.start)
   }
 }
 
-object AbstractInstrumentation {
+private[spark] object MetricsSystem {
+  val registry = new MetricRegistry()
+  
   val DEFAULT_SINKS = Map(
       "console" -> "spark.metrics.sink.ConsoleSink",
       "csv" -> "spark.metrics.sink.CsvSink")
@@ -88,4 +94,6 @@ object AbstractInstrumentation {
       "minute" -> TimeUnit.MINUTES,
       "hour" -> TimeUnit.HOURS,
       "day" -> TimeUnit.DAYS)
+      
+   def createMetricsSystem(instance: String) = new MetricsSystem(instance)
 }
\ No newline at end of file
diff --git a/core/src/main/scala/spark/metrics/sink/ConsoleSink.scala b/core/src/main/scala/spark/metrics/sink/ConsoleSink.scala
index 5426af8c4c..b49a211fb3 100644
--- a/core/src/main/scala/spark/metrics/sink/ConsoleSink.scala
+++ b/core/src/main/scala/spark/metrics/sink/ConsoleSink.scala
@@ -5,7 +5,7 @@ import java.util.concurrent.TimeUnit
 
 import com.codahale.metrics.{ConsoleReporter, MetricRegistry}
 
-import spark.metrics.AbstractInstrumentation
+import spark.metrics.MetricsSystem
 
 class ConsoleSink(val property: Properties, val registry: MetricRegistry) extends Sink {
   val pollPeriod = Option(property.getProperty(ConsoleSink.CONSOLE_KEY_PERIOD)) match {
@@ -14,13 +14,13 @@ class ConsoleSink(val property: Properties, val registry: MetricRegistry) extend
   }
   
   val pollUnit = Option(property.getProperty(ConsoleSink.CONSOLE_KEY_UNIT)) match {
-    case Some(s) => AbstractInstrumentation.timeUnits(s)
-    case None => AbstractInstrumentation.timeUnits(ConsoleSink.CONSOLE_DEFAULT_UNIT)
+    case Some(s) => MetricsSystem.timeUnits(s)
+    case None => MetricsSystem.timeUnits(ConsoleSink.CONSOLE_DEFAULT_UNIT)
   }
   
   var reporter: ConsoleReporter = _
   
-  override def registerSink() {
+  override def start() {
     reporter = ConsoleReporter.forRegistry(registry)
       .convertDurationsTo(TimeUnit.MILLISECONDS)
       .convertRatesTo(TimeUnit.SECONDS)
@@ -29,7 +29,7 @@ class ConsoleSink(val property: Properties, val registry: MetricRegistry) extend
     reporter.start(pollPeriod, pollUnit)  
   }
   
-  override def unregisterSink() {
+  override def stop() {
     reporter.stop()
   }
 }
diff --git a/core/src/main/scala/spark/metrics/sink/CsvSink.scala b/core/src/main/scala/spark/metrics/sink/CsvSink.scala
index 1d663f6cff..3f572c8e05 100644
--- a/core/src/main/scala/spark/metrics/sink/CsvSink.scala
+++ b/core/src/main/scala/spark/metrics/sink/CsvSink.scala
@@ -6,7 +6,7 @@ import java.util.concurrent.TimeUnit
 
 import com.codahale.metrics.{CsvReporter, MetricRegistry}
 
-import spark.metrics.AbstractInstrumentation
+import spark.metrics.MetricsSystem
 
 class CsvSink(val property: Properties, val registry: MetricRegistry) extends Sink {
   val pollPeriod = Option(property.getProperty(CsvSink.CSV_KEY_PERIOD)) match {
@@ -15,8 +15,8 @@ class CsvSink(val property: Properties, val registry: MetricRegistry) extends Si
   }
   
   val pollUnit = Option(property.getProperty(CsvSink.CSV_KEY_UNIT)) match {
-    case Some(s) => AbstractInstrumentation.timeUnits(s)
-    case None => AbstractInstrumentation.timeUnits(CsvSink.CSV_DEFAULT_UNIT)
+    case Some(s) => MetricsSystem.timeUnits(s)
+    case None => MetricsSystem.timeUnits(CsvSink.CSV_DEFAULT_UNIT)
   }
   
   val pollDir = Option(property.getProperty(CsvSink.CSV_KEY_DIR)) match {
@@ -26,7 +26,7 @@ class CsvSink(val property: Properties, val registry: MetricRegistry) extends Si
   
   var reporter: CsvReporter = _
   
-  override def registerSink() {
+  override def start() {
     reporter = CsvReporter.forRegistry(registry)
       .formatFor(Locale.US)
       .convertDurationsTo(TimeUnit.MILLISECONDS)
@@ -36,7 +36,7 @@ class CsvSink(val property: Properties, val registry: MetricRegistry) extends Si
     reporter.start(pollPeriod, pollUnit)  
   }
   
-  override def unregisterSink() {
+  override def stop() {
     reporter.stop()
   }
 }
diff --git a/core/src/main/scala/spark/metrics/sink/JmxSink.scala b/core/src/main/scala/spark/metrics/sink/JmxSink.scala
index 56e5677700..e223dc26e9 100644
--- a/core/src/main/scala/spark/metrics/sink/JmxSink.scala
+++ b/core/src/main/scala/spark/metrics/sink/JmxSink.scala
@@ -5,12 +5,12 @@ import com.codahale.metrics.{JmxReporter, MetricRegistry}
 class JmxSink(registry: MetricRegistry) extends Sink {
   var reporter: JmxReporter = _
   
-  override def registerSink() {
+  override def start() {
     reporter = JmxReporter.forRegistry(registry).build()
     reporter.start()
   }
   
-  override def unregisterSink() {
+  override def stop() {
     reporter.stop()
   }
   
diff --git a/core/src/main/scala/spark/metrics/sink/Sink.scala b/core/src/main/scala/spark/metrics/sink/Sink.scala
index 26052b7231..9fef894fde 100644
--- a/core/src/main/scala/spark/metrics/sink/Sink.scala
+++ b/core/src/main/scala/spark/metrics/sink/Sink.scala
@@ -1,7 +1,7 @@
 package spark.metrics.sink
 
 trait Sink {
-  def registerSink: Unit
+  def start: Unit
   
-  def unregisterSink: Unit
+  def stop: Unit
 }
\ No newline at end of file
diff --git a/core/src/main/scala/spark/metrics/source/JvmSource.scala b/core/src/main/scala/spark/metrics/source/JvmSource.scala
index 8f6bf48843..7a7c1b6ffb 100644
--- a/core/src/main/scala/spark/metrics/source/JvmSource.scala
+++ b/core/src/main/scala/spark/metrics/source/JvmSource.scala
@@ -1,17 +1,23 @@
 package spark.metrics.source
 
-import com.codahale.metrics.MetricRegistry
-import com.codahale.metrics.jvm.{MemoryUsageGaugeSet, GarbageCollectorMetricSet}
+import java.util.{Map, HashMap => JHashMap}
 
-class JvmSource(registry: MetricRegistry) extends Source {
-  // Initialize memory usage gauge for jvm
-  val memUsageMetricSet = new MemoryUsageGaugeSet
-  
-  // Initialize garbage collection usage gauge for jvm
-  val gcMetricSet = new GarbageCollectorMetricSet
-  
-  override def registerSource() {
-    registry.registerAll(memUsageMetricSet)
-    registry.registerAll(gcMetricSet)
+import com.codahale.metrics.Metric
+import com.codahale.metrics.jvm.{GarbageCollectorMetricSet, MemoryUsageGaugeSet}
+
+class JvmSource extends Source {
+  override def sourceName = "jvm"
+    
+  override def getMetrics(): Map[String, Metric] = {
+    val gauges = new JHashMap[String, Metric]
+    
+    import scala.collection.JavaConversions._
+    val gcMetricSet = new GarbageCollectorMetricSet
+    gcMetricSet.getMetrics.foreach(kv => gauges.put(kv._1, kv._2))
+    
+    val memGaugeSet = new MemoryUsageGaugeSet
+    memGaugeSet.getMetrics.foreach(kv => gauges.put(kv._1, kv._2))
+    		
+    gauges
   }
 }
\ No newline at end of file
diff --git a/core/src/main/scala/spark/metrics/source/Source.scala b/core/src/main/scala/spark/metrics/source/Source.scala
index 35cfe0c8ff..edd59de46a 100644
--- a/core/src/main/scala/spark/metrics/source/Source.scala
+++ b/core/src/main/scala/spark/metrics/source/Source.scala
@@ -1,5 +1,7 @@
 package spark.metrics.source
 
-trait Source {
-  def registerSource: Unit
+import com.codahale.metrics.MetricSet
+
+trait Source extends MetricSet {
+  def sourceName: String
 }
\ No newline at end of file