[SPARK-13238][CORE] Add ganglia dmax parameter

The current ganglia reporter doesn't set metric expiration time (dmax). The metrics of all finished applications are indefinitely left displayed in ganglia web. The dmax parameter allows user to set the lifetime of the metrics. The default value is 0 for compatibility with previous versions.

Author: Ekasit Kijsipongse <ekasitk@gmail.com>

Closes #11127 from ekasitk/ganglia-dmax.

conf/metrics.properties.template

@@ -93,6 +93,7 @@
 #   period    10         Poll period
 #   unit      seconds    Unit of the poll period
 #   ttl       1          TTL of messages sent by Ganglia
+#   dmax      0          Lifetime in seconds of metrics (0 never expired)
 #   mode      multicast  Ganglia network mode ('unicast' or 'multicast')
 
 # org.apache.spark.metrics.sink.JmxSink

external/spark-ganglia-lgpl/src/main/scala/org/apache/spark/metrics/sink/GangliaSink.scala

@@ -46,6 +46,9 @@ class GangliaSink(val property: Properties, val registry: MetricRegistry,
   val GANGLIA_KEY_HOST = "host"
   val GANGLIA_KEY_PORT = "port"
 
+  val GANGLIA_KEY_DMAX = "dmax"
+  val GANGLIA_DEFAULT_DMAX = 0
+
   def propertyToOption(prop: String): Option[String] = Option(property.getProperty(prop))
 
   if (!propertyToOption(GANGLIA_KEY_HOST).isDefined) {
@@ -59,6 +62,7 @@ class GangliaSink(val property: Properties, val registry: MetricRegistry,
   val host = propertyToOption(GANGLIA_KEY_HOST).get
   val port = propertyToOption(GANGLIA_KEY_PORT).get.toInt
   val ttl = propertyToOption(GANGLIA_KEY_TTL).map(_.toInt).getOrElse(GANGLIA_DEFAULT_TTL)
+  val dmax = propertyToOption(GANGLIA_KEY_DMAX).map(_.toInt).getOrElse(GANGLIA_DEFAULT_DMAX)
   val mode: UDPAddressingMode = propertyToOption(GANGLIA_KEY_MODE)
     .map(u => GMetric.UDPAddressingMode.valueOf(u.toUpperCase)).getOrElse(GANGLIA_DEFAULT_MODE)
   val pollPeriod = propertyToOption(GANGLIA_KEY_PERIOD).map(_.toInt)
@@ -73,6 +77,7 @@ class GangliaSink(val property: Properties, val registry: MetricRegistry,
   val reporter: GangliaReporter = GangliaReporter.forRegistry(registry)
       .convertDurationsTo(TimeUnit.MILLISECONDS)
       .convertRatesTo(TimeUnit.SECONDS)
+      .withDMax(dmax)
       .build(ganglia)
 
   override def start() {