address review comment

instrumentation/kamon-akka-http/src/test/scala/kamon/akka/http/AkkaHttpClientTracingSpec.scala

@@ -18,18 +18,16 @@ package kamon.akka.http
 
 import akka.actor.ActorSystem
 import akka.http.scaladsl.Http
-import akka.http.scaladsl.model.headers.RawHeader
 import akka.http.scaladsl.model.HttpRequest
+import akka.http.scaladsl.model.headers.RawHeader
 import akka.stream.ActorMaterializer
 import kamon.Kamon
-import kamon.testkit._
-import kamon.trace.Span
 import kamon.tag.Lookups.{plain, plainBoolean, plainLong}
-import okhttp3.Request
-import org.scalatest.concurrent.Eventually
-import org.scalatest.{BeforeAndAfterAll, Matchers, OptionValues, WordSpecLike}
+import kamon.testkit._
 import org.json4s._
 import org.json4s.native.JsonMethods._
+import org.scalatest.concurrent.Eventually
+import org.scalatest.{BeforeAndAfterAll, Matchers, OptionValues, WordSpecLike}
 
 import scala.concurrent.duration._
 

instrumentation/kamon-akka-http/src/test/scala/kamon/akka/http/AkkaHttpServerTracingSpec.scala

@@ -19,18 +19,16 @@ package kamon.akka.http
 import java.util.UUID
 
 import akka.actor.ActorSystem
-import akka.http.scaladsl.UseHttp2
-import akka.http.scaladsl.unmarshalling.Unmarshal
 import akka.stream.ActorMaterializer
 import javax.net.ssl.{HostnameVerifier, SSLSession}
-import kamon.testkit._
 import kamon.tag.Lookups.{plain, plainBoolean, plainLong}
+import kamon.testkit._
 import kamon.trace.Span.Mark
+import okhttp3.{OkHttpClient, Request}
 import org.scalatest._
 import org.scalatest.concurrent.{Eventually, ScalaFutures}
 
 import scala.concurrent.duration._
-import okhttp3.{OkHttpClient, Request}
 
 class AkkaHttpServerTracingSpec extends WordSpecLike with Matchers with ScalaFutures with Inside with BeforeAndAfterAll
     with MetricInspection.Syntax with Reconfigure with TestWebServer with Eventually with OptionValues with TestSpanReporter {

instrumentation/kamon-instrumentation-common/src/main/scala/kamon/instrumentation/http/HttpClientInstrumentation.scala

@@ -5,7 +5,6 @@ package http
 import com.typesafe.config.Config
 import kamon.context.Context
 import kamon.instrumentation.http.HttpClientInstrumentation.Settings
-import kamon.instrumentation.http.HttpInstrumentation.OperationNameSettings
 import kamon.instrumentation.tag.TagKeys
 import kamon.instrumentation.trace.SpanTagger
 import kamon.instrumentation.trace.SpanTagger.TagMode
@@ -133,7 +132,7 @@ object HttpClientInstrumentation {
 
     private def createClientSpan(requestMessage: HttpMessage.Request, context: Context): Span = {
       val span = Kamon
-        .clientSpanBuilder(HttpInstrumentation.operationName(settings.operationNameSettings, requestMessage), component)
+        .clientSpanBuilder(settings.operationNameSettings.operationName(requestMessage), component)
         .context(context)
 
       if(!settings.enableSpanMetrics)

instrumentation/kamon-instrumentation-common/src/main/scala/kamon/instrumentation/http/HttpServerInstrumentation.scala

@@ -6,7 +6,6 @@ import java.time.Duration
 
 import com.typesafe.config.Config
 import kamon.context.Context
-import kamon.instrumentation.http.HttpInstrumentation.OperationNameSettings
 import kamon.instrumentation.http.HttpServerInstrumentation.Settings
 import kamon.instrumentation.trace.SpanTagger.TagMode
 import kamon.instrumentation.tag.TagKeys
@@ -296,7 +295,7 @@ object HttpServerInstrumentation {
 
 
     private def buildServerSpan(context: Context, request: HttpMessage.Request, deferSamplingDecision: Boolean): Span = {
-      val span = Kamon.serverSpanBuilder(HttpInstrumentation.operationName(settings.operationNameSettings, request), component)
+      val span = Kamon.serverSpanBuilder(settings.operationNameSettings.operationName(request), component)
       span.context(context)
 
       if(!settings.enableSpanMetrics)

instrumentation/kamon-instrumentation-common/src/main/scala/kamon/instrumentation/http/OperationNameSettings.scala

@@ -0,0 +1,18 @@
+package kamon.instrumentation.http
+
+import kamon.util.Filter
+
+final case class OperationNameSettings(defaultOperationName: String,
+                                       operationMappings: Map[Filter.Glob, String],
+                                       operationNameGenerator: HttpOperationNameGenerator) {
+  private[http] def operationName(request: HttpMessage.Request): String = {
+    val requestPath = request.path
+    //first apply any mappings rules
+    val customMapping = operationMappings.collectFirst {
+      case (pattern, operationName) if pattern.accept(requestPath) => operationName
+    }.orElse( //fallback to use any configured name generator
+      operationNameGenerator.name(request)
+    )
+    customMapping.getOrElse(defaultOperationName)
+  }
+}