+ system-metrics: two-phase sigar loading

* update slf4jVersion
* redirect JUL and LOG4J logging to SLF4J
* use two-phase sigar loading

4 files changed, 63 insertions, 7 deletions

diff --git a/kamon-system-metrics/src/main/resources/reference.conf b/kamon-system-metrics/src/main/resources/reference.conf
index 0fab129f..4d564e38 100644
--- a/kamon-system-metrics/src/main/resources/reference.conf
+++ b/kamon-system-metrics/src/main/resources/reference.conf
@@ -2,6 +2,10 @@
 # Kamon-System-Metrics Reference Configuration #
 # ============================================ #
 
+# Sigar provisioner native library extract location.
+# Use per-application-instance scoped location, such as program working directory.
+kamon.sigar.folder = ${user.dir}"/native"
+
 kamon {
   metrics {
     precision {
diff --git a/kamon-system-metrics/src/main/scala/kamon/system/SystemMetricsCollector.scala b/kamon-system-metrics/src/main/scala/kamon/system/SystemMetricsCollector.scala
index bb7fa105..8094cac4 100644
--- a/kamon-system-metrics/src/main/scala/kamon/system/SystemMetricsCollector.scala
+++ b/kamon-system-metrics/src/main/scala/kamon/system/SystemMetricsCollector.scala
@@ -158,16 +158,34 @@ class SystemMetricsCollector(collectInterval: FiniteDuration) extends Actor with
     rcs.global.record(contextSwitches)
   }
 
+  def verifiedSigarInstance: SigarProxy = {
+    val sigar = new Sigar()
+    printBanner(sigar)
+    sigar
+  }
+
+  def provisionSigarLibrary: Unit = {
+    val folder = context.system.settings.config.getString("kamon.sigar.folder")
+    SigarProvisioner.provision(new File(folder))
+  }
+
   def createSigarInstance: SigarProxy = {
-    val tempFolder = new File(System.getProperty("java.io.tmpdir"))
 
+    // 1) Assume that library is already provisioned.
+    try {
+      return verifiedSigarInstance
+    } catch {
+      // Not using [[Try]] - any error is non-fatal in this case.
+      case e: Throwable ⇒ log.info(s"Sigar is not yet provisioned: ${e}")
+    }
+
+    // 2) Attempt to provision library via sigar-loader.
     try {
-      SigarProvisioner.provision(tempFolder)
-      val sigar = new Sigar()
-      printBanner(sigar)
-      sigar
+      provisionSigarLibrary
+      return verifiedSigarInstance
     } catch {
-      case NonFatal(t) ⇒ throw new UnexpectedSigarException("Failed to load sigar")
+      // Not using [[Try]] - any error is non-fatal in this case.
+      case e: Throwable ⇒ throw new UnexpectedSigarException(s"Failed to load Sigar: ${e}")
     }
   }
 }
diff --git a/kamon-system-metrics/src/test/scala/kamon/metrics/RedirectLogging.scala b/kamon-system-metrics/src/test/scala/kamon/metrics/RedirectLogging.scala
new file mode 100644
index 00000000..fbf42cf0
--- /dev/null
+++ b/kamon-system-metrics/src/test/scala/kamon/metrics/RedirectLogging.scala
@@ -0,0 +1,34 @@
+/* =========================================================================================
+ * Copyright © 2013-2014 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.metric
+
+import java.util.logging.LogManager
+import org.slf4j.bridge.SLF4JBridgeHandler
+
+/**
+ * Redirect different logging sources to SLF4J.
+ */
+trait RedirectLogging {
+
+  def redirectLogging(): Unit = {
+    // Redirect JUL to SLF4J.
+    LogManager.getLogManager().reset();
+    SLF4JBridgeHandler.install();
+  }
+
+  redirectLogging()
+
+}
diff --git a/kamon-system-metrics/src/test/scala/kamon/metrics/SystemMetricsSpec.scala b/kamon-system-metrics/src/test/scala/kamon/metrics/SystemMetricsSpec.scala
index 058dafb4..714a1e6d 100644
--- a/kamon-system-metrics/src/test/scala/kamon/metrics/SystemMetricsSpec.scala
+++ b/kamon-system-metrics/src/test/scala/kamon/metrics/SystemMetricsSpec.scala
@@ -33,7 +33,7 @@ import org.scalatest.{ Matchers, WordSpecLike }
 
 import scala.concurrent.duration._
 
-class SystemMetricsSpec extends TestKitBase with WordSpecLike with Matchers {
+class SystemMetricsSpec extends TestKitBase with WordSpecLike with Matchers with RedirectLogging {
   implicit lazy val system: ActorSystem = ActorSystem("system-metrics-spec", ConfigFactory.parseString(
     """
       |akka {