fix the FastFuture instrumentation for Scala 2.13

.travis.yml

@@ -1,9 +1,12 @@
 language: scala
+script:
+  - sbt +test
 scala:
-   - 2.12.6
+  - 2.12.8
 jdk:
-   - oraclejdk8
+  - openjdk8
 before_script:
   - mkdir $TRAVIS_BUILD_DIR/tmp
   - export SBT_OPTS="-Djava.io.tmpdir=$TRAVIS_BUILD_DIR/tmp"
 sudo: false
+

kamon-akka-http/src/main/resources/reference.conf

@@ -239,7 +239,7 @@ kanela.modules {
     ]
 
     within = [
-      ".*"
+      "akka.http.*"
     ]
   }
 }

kamon-akka-http/src/main/scala-2.13/kamon/instrumentation/akka/http/AkkaHttpServerInstrumentation.scala

@@ -18,7 +18,7 @@ import kanela.agent.api.instrumentation.InstrumentationBuilder
 import kanela.agent.api.instrumentation.mixin.Initializer
 import kanela.agent.libs.net.bytebuddy.implementation.bind.annotation._
 
-import scala.concurrent.{ExecutionContext, Future, Promise}
+import scala.concurrent.{ExecutionContext, Future, Promise, Batchable}
 import scala.util.control.NonFatal
 import scala.util.{Failure, Success, Try}
 
@@ -67,12 +67,12 @@ class AkkaHttpServerInstrumentation extends InstrumentationBuilder {
     */
   onTypes("akka.http.scaladsl.util.FastFuture$FulfilledFuture", "akka.http.scaladsl.util.FastFuture$ErrorFuture")
     .mixin(classOf[HasContext.MixinWithInitializer])
-      .advise(method("transform"), InvokeWithCapturedContext)
-      .advise(method("transformWith"), InvokeWithCapturedContext)
-      .advise(method("onComplete"), InvokeWithCapturedContext)
+    .advise(method("transform"), InvokeWithCapturedContext)
+    .advise(method("transformWith"), InvokeWithCapturedContext)
+    .advise(method("onComplete"), InvokeWithCapturedContext)
 
   onType("akka.http.scaladsl.util.FastFuture$")
-    .intercept(method("transformWith$extension"), FastFutureTransformWithAdvice)
+    .intercept(method("transformWith$extension").and(takesArguments(4)), FastFutureTransformWithAdvice)
 }
 
 trait HasMatchingContext {
@@ -243,9 +243,15 @@ object FastFutureTransformWithAdvice {
       try f(x)
       catch { case NonFatal(e) => FastFuture.failed(e) }
 
-    // If we get a FulfilledFuture or ErrorFuture, those will have the HasContext mixin,
-    // otherwise we are getting a regular Future which has the context mixed into its value.
-    if(future.isInstanceOf[HasContext])
+    // If we get a FulfilledFuture or ErrorFuture, those will have the HasContext mixin but since Scala 2.13 the
+    // "future" will also have a HasContext mixin (its actually a Transformation instance) and since we can't directly
+    // access FulfilledFuture or ErrorFuture, we are assuming that if it got to this point, it HasContext and it is not
+    // a Batchable (i.e. a Transformation) then we can do the same we were doing for previous Scala versions.
+    //
+    // When we get a regular Future the path is a bit different because the actual Context is not stored in the Future
+    // but in the value itself via HasContext instrumentation on scala.util.Try
+    //
+    if(future.isInstanceOf[HasContext] && !future.isInstanceOf[Batchable])
       zuper.call()
     else {
       future.value match {

kamon-akka-http/src/test/resources/application.conf

@@ -4,21 +4,4 @@ kamon {
   }
 
   trace.sampler = "always"
-}
-
-kanela.log-level = INFO
-//kanela.debug-mode = yes
-
-
-kanela {
-  class-dumper {
-    # Enables the class dumper.
-    enabled = true
-    # Default dir.
-    dir = ${user.home}"/kanela-agent/dump/akka-http"
-    # By default build a jar containing all instrumented classes.
-    create-jar = false
-    # Default jar name.
-    jar-name = "instrumented-classes-akka-http"
-  }
 }