1 files changed, 28 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/trace/UowDirectives.scala b/kamon-core/src/main/scala/kamon/trace/UowDirectives.scala
new file mode 100644
index 00000000..392f53b8
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/UowDirectives.scala
@@ -0,0 +1,28 @@
+package kamon.trace
+
+import spray.routing.directives.BasicDirectives
+import spray.routing._
+import kamon.Tracer
+import java.util.concurrent.atomic.AtomicLong
+import scala.util.Try
+import java.net.InetAddress
+
+trait UowDirectives extends BasicDirectives {
+  def uow: Directive0 = mapRequest { request =>
+    val uowHeader = request.headers.find(_.name == "X-UOW")
+
+    val generatedUow = uowHeader.map(_.value).getOrElse(UowDirectives.newUow)
+    Tracer.set(Tracer.context().getOrElse(Tracer.newTraceContext()).copy(uow = generatedUow))
+
+    request
+  }
+}
+
+object UowDirectives {
+  val uowCounter = new AtomicLong
+
+  val hostnamePrefix = Try(InetAddress.getLocalHost.getHostName).getOrElse("unknown-localhost")
+
+  def newUow = "%s-%s".format(hostnamePrefix, uowCounter.incrementAndGet())
+
+}
+\ No newline at end of file