1 files changed, 57 insertions, 0 deletions
diff --git a/kamon-system-metrics/src/main/scala/kamon/system/sigar/MemoryMetrics.scala b/kamon-system-metrics/src/main/scala/kamon/system/sigar/MemoryMetrics.scala
new file mode 100644
index 00000000..787c9f2f
--- /dev/null
+++ b/kamon-system-metrics/src/main/scala/kamon/system/sigar/MemoryMetrics.scala
@@ -0,0 +1,57 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2015 the kamon project <http://kamon.io/>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ * =========================================================================================
+ */
+
+package kamon.system.sigar
+
+import kamon.metric.GenericEntityRecorder
+import kamon.metric.instrument.{ Memory, InstrumentFactory }
+import org.hyperic.sigar.Sigar
+
+/**
+ *  System memory usage metrics, as reported by Sigar:
+ *    - used: Total used system memory.
+ *    - free: Total free system memory (e.g. Linux plus cached).
+ *    - swap-used: Total used system swap.
+ *    - swap-free: Total free system swap.
+ */
+class MemoryMetrics(sigar: Sigar, instrumentFactory: InstrumentFactory) extends GenericEntityRecorder(instrumentFactory) with SigarMetric {
+  val used = histogram("memory-used", Memory.Bytes)
+  val cached = histogram("memory-cache-and-buffer", Memory.Bytes)
+  val free = histogram("memory-free", Memory.Bytes)
+  val total = histogram("memory-total", Memory.Bytes)
+  val swapUsed = histogram("swap-used", Memory.Bytes)
+  val swapFree = histogram("swap-free", Memory.Bytes)
+
+  def update(): Unit = {
+    val mem = sigar.getMem
+    val swap = sigar.getSwap
+    val cachedMemory = if (mem.getActualFree > mem.getFree) mem.getActualFree - mem.getFree else 0L
+
+    used.record(mem.getActualUsed)
+    free.record(mem.getActualFree)
+    cached.record(cachedMemory)
+    total.record(mem.getTotal)
+    swapUsed.record(swap.getUsed)
+    swapFree.record(swap.getFree)
+  }
+}
+
+object MemoryMetrics extends SigarMetricRecorderCompanion("memory") {
+
+  def apply(sigar: Sigar, instrumentFactory: InstrumentFactory): MemoryMetrics =
+    new MemoryMetrics(sigar, instrumentFactory)
+}
+