1 files changed, 35 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/trace/SpanCustomizer.scala b/kamon-core/src/main/scala/kamon/trace/SpanCustomizer.scala
new file mode 100644
index 00000000..4c6220ce
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/SpanCustomizer.scala
@@ -0,0 +1,35 @@
+package kamon.trace
+
+import kamon.context.Key
+import kamon.trace.Tracer.SpanBuilder
+
+/**
+  * Allows users to customize and add additional information to Spans created by instrumentation. The typical use
+  * case for SpanCustomizer instances is to provide proper operation names in situations where the instrumentation
+  * is unable to generate a reasonable enough operation name, e.g. JDBC and HTTP Client calls, instead of having a
+  * default operation name using the statement type or target host a SpanCustomizer can be provided to assign operation
+  * names like "queryUsers" or "getUserProfile" instead.
+  *
+  * Instrumentation wanting to take advantage of SpanCustomizers should look for an instance in the current context
+  * using SpanCustomizer.ContextKey.
+  *
+  */
+trait SpanCustomizer {
+  def customize(spanBuilder: SpanBuilder): SpanBuilder
+}
+
+object SpanCustomizer {
+
+  val Noop = new SpanCustomizer {
+    override def customize(spanBuilder: SpanBuilder): SpanBuilder = spanBuilder
+  }
+
+  val ContextKey = Key.local[SpanCustomizer]("span-customizer", Noop)
+
+  def forOperationName(operationName: String): SpanCustomizer = new SpanCustomizer {
+    override def customize(spanBuilder: SpanBuilder): SpanBuilder =
+      spanBuilder.withOperationName(operationName)
+  }
+}
+
+