on the crazy path to a better Kamon :D

1 files changed, 86 insertions, 0 deletions

diff --git a/kamon-core/src/main/scala/kamon/metric/MetricRegistry.scala b/kamon-core/src/main/scala/kamon/metric/MetricRegistry.scala
new file mode 100644
index 00000000..c6513f1a
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/metric/MetricRegistry.scala
@@ -0,0 +1,86 @@
+package kamon
+package metric
+
+import java.time.Duration
+import java.util.concurrent.atomic.AtomicReference
+
+import com.typesafe.config.Config
+import com.typesafe.scalalogging.Logger
+import kamon.metric.instrument._
+import kamon.util.MeasurementUnit
+
+import scala.collection.concurrent.TrieMap
+
+
+class MetricRegistry(initialConfig: Config) extends MetricsSnapshotGenerator {
+  private val logger = Logger(classOf[MetricRegistry])
+  private val metrics = TrieMap.empty[String, MetricEntry]
+  private val instrumentFactory = new AtomicReference[InstrumentFactory]()
+  reconfigure(initialConfig)
+
+  def reconfigure(config: Config): Unit = synchronized {
+    instrumentFactory.set(InstrumentFactory.fromConfig(config))
+  }
+
+  def histogram(name: String, unit: MeasurementUnit, tags: Map[String, String], dynamicRange: Option[DynamicRange]): Histogram =
+    lookupInstrument(name, unit, tags, InstrumentType.Histogram, instrumentFactory.get().buildHistogram(dynamicRange))
+
+  def counter(name: String, unit: MeasurementUnit, tags: Map[String, String]): Counter =
+    lookupInstrument(name, unit, tags, InstrumentType.Counter, instrumentFactory.get().buildCounter)
+
+  def gauge(name: String, unit: MeasurementUnit, tags: Map[String, String]): Gauge =
+    lookupInstrument(name, unit, tags, InstrumentType.Gauge, instrumentFactory.get().buildGauge)
+
+  def minMaxCounter(name: String, unit: MeasurementUnit, tags: Map[String, String], dynamicRange: Option[DynamicRange], sampleInterval: Option[Duration]): MinMaxCounter =
+    lookupInstrument(name, unit, tags, InstrumentType.MinMaxCounter, instrumentFactory.get().buildMinMaxCounter(dynamicRange, sampleInterval))
+
+
+  override def snapshot(): MetricsSnapshot = synchronized {
+    var histograms = Seq.empty[DistributionSnapshot]
+    var mmCounters = Seq.empty[DistributionSnapshot]
+    var counters = Seq.empty[SingleValueSnapshot]
+    var gauges = Seq.empty[SingleValueSnapshot]
+
+    for {
+      metricEntry <- metrics.values
+      instrument  <- metricEntry.instruments.values
+    } {
+      metricEntry.instrumentType match {
+        case InstrumentType.Histogram     => histograms = histograms :+ instrument.asInstanceOf[SnapshotableHistogram].snapshot()
+        case InstrumentType.MinMaxCounter => mmCounters = mmCounters :+ instrument.asInstanceOf[SnapshotableMinMaxCounter].snapshot()
+        case InstrumentType.Gauge         => gauges = gauges :+ instrument.asInstanceOf[SnapshotableGauge].snapshot()
+        case InstrumentType.Counter       => counters = counters :+ instrument.asInstanceOf[SnapshotableCounter].snapshot()
+      }
+    }
+
+    MetricsSnapshot(histograms, mmCounters, gauges, counters)
+  }
+
+  private def lookupInstrument[T](name: String, measurementUnit: MeasurementUnit, tags: Map[String, String],
+      instrumentType: InstrumentType, builder: (String, Map[String, String], MeasurementUnit) => T): T = {
+
+    val entry = metrics.atomicGetOrElseUpdate(name, MetricEntry(instrumentType, measurementUnit, TrieMap.empty))
+    if(entry.instrumentType != instrumentType)
+      sys.error(s"Tried to use metric [$name] as a [${instrumentType.name}] but it is already defined as [${entry.instrumentType.name}] ")
+
+    if(entry.unit != measurementUnit)
+      logger.warn("Ignoring attempt to use measurement unit [{}] on metric [name={}, tags={}], the metric uses [{}]",
+        measurementUnit.magnitude.name, name, tags.prettyPrint(), entry.unit.magnitude.name)
+
+    entry.instruments.getOrElseUpdate(tags, builder(name, tags, measurementUnit)).asInstanceOf[T]
+  }
+
+  private case class InstrumentType(name: String)
+  private object InstrumentType {
+    val Histogram     = InstrumentType("Histogram")
+    val MinMaxCounter = InstrumentType("MinMaxCounter")
+    val Counter       = InstrumentType("Counter")
+    val Gauge         = InstrumentType("Gauge")
+  }
+
+  private case class MetricEntry(instrumentType: InstrumentType, unit: MeasurementUnit, instruments: TrieMap[Map[String, String], Any])
+}
+
+trait MetricsSnapshotGenerator {
+  def snapshot(): MetricsSnapshot
+}