add kamon.init.attach-instrumentation setting (#1278)

kamon-io · May 19, 2023 · c3f0655 · c3f0655
1 parent 4f18bba
commit c3f0655
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Showing 3 changed files with 20 additions and 3 deletions.
diff --git a/core/kamon-core/src/main/resources/reference.conf b/core/kamon-core/src/main/resources/reference.conf
@@ -19,6 +19,11 @@ kamon {
 
     # Hides the Kamon banner shown during Kamon's init process
     hide-banner = no
+
+    # Controls whether Kamon should try to use the runtime attacher during initialization. It is safe to disable
+    # the runtime attacher if you don't need instrumentation at all or if you are applying instrumentation via the
+    # -javaagent JVM option.
+    attach-instrumentation = yes
   }
 
   environment {

diff --git a/core/kamon-core/src/main/scala/kamon/Configuration.scala b/core/kamon-core/src/main/scala/kamon/Configuration.scala
@@ -17,7 +17,7 @@
 package kamon
 
 import com.typesafe.config.{Config, ConfigFactory}
-import kamon.Configuration.EnabledConfigurationName
+import kamon.Configuration.{InitAttachInstrumentationConfigurationName, EnabledConfigurationName}
 import org.slf4j.LoggerFactory
 
 import scala.util.control.NonFatal
@@ -30,6 +30,7 @@ trait Configuration {
   private var _currentConfig: Config = loadInitialConfiguration()
   private var _onReconfigureHooks = Seq.empty[Configuration.OnReconfigureHook]
   @volatile private var _enabled: Boolean = _currentConfig.getBoolean(EnabledConfigurationName)
+  @volatile private var _shouldAttachInstrumentation: Boolean = _currentConfig.getBoolean(InitAttachInstrumentationConfigurationName)
 
 
   /**
@@ -41,12 +42,14 @@ trait Configuration {
   def enabled(): Boolean =
     _enabled
 
+
   /**
     * Supply a new Config instance to rule Kamon's world.
     */
   def reconfigure(newConfig: Config): Unit = synchronized {
     _currentConfig = newConfig
     _enabled = newConfig.getBoolean(EnabledConfigurationName)
+    _shouldAttachInstrumentation = newConfig.getBoolean(InitAttachInstrumentationConfigurationName)
     _onReconfigureHooks.foreach(hook => {
       try {
         hook.onReconfigure(newConfig)
@@ -74,6 +77,8 @@ trait Configuration {
     })
   }
 
+  protected def shouldAttachInstrumentation(): Boolean =
+    _shouldAttachInstrumentation
 
   private def loadInitialConfiguration(): Config = {
     import System.{err, lineSeparator}
@@ -104,6 +109,7 @@ trait Configuration {
 object Configuration {
 
   private val EnabledConfigurationName = "kamon.enabled"
+  private val InitAttachInstrumentationConfigurationName = "kamon.init.attach-instrumentation"
 
   trait OnReconfigureHook {
     def onReconfigure(newConfig: Config): Unit

diff --git a/core/kamon-core/src/main/scala/kamon/Init.scala b/core/kamon-core/src/main/scala/kamon/Init.scala
@@ -39,7 +39,10 @@ trait Init { self: ModuleManagement with Configuration with CurrentStatus with M
     */
   def init(): Unit = {
     if(enabled()) {
-      self.attachInstrumentation()
+      if(shouldAttachInstrumentation()) {
+        self.attachInstrumentation()
+      }
+
       self.initScheduler()
       self.loadModules()
       self.moduleRegistry().init()
@@ -58,7 +61,10 @@ trait Init { self: ModuleManagement with Configuration with CurrentStatus with M
     self.reconfigure(config)
 
     if(enabled()) {
-      self.attachInstrumentation()
+      if (shouldAttachInstrumentation()) {
+        self.attachInstrumentation()
+      }
+
       self.initScheduler()
       self.loadModules()
       self.moduleRegistry().init()