1 files changed, 67 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/ContextPropagation.scala b/kamon-core/src/main/scala/kamon/ContextPropagation.scala
new file mode 100644
index 00000000..518aa021
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/ContextPropagation.scala
@@ -0,0 +1,67 @@
+package kamon
+
+import com.typesafe.config.Config
+import kamon.context.HttpPropagation
+
+trait ContextPropagation { self: Configuration with ClassLoading =>
+  @volatile private var _propagationComponents: ContextPropagation.Components = _
+  @volatile private var _defaultHttpPropagation: HttpPropagation = _
+
+  // Initial configuration and reconfigures
+  init(self.config)
+  self.onReconfigure(newConfig => self.init(newConfig))
+
+
+  /**
+    * Retrieves the HTTP propagation channel with the supplied name. Propagation channels are configured on the
+    * kamon.propagation.channels configuration setting.
+    *
+    * @param channelName Channel name to retrieve.
+    * @return The HTTP propagation, if defined.
+    */
+  def httpPropagation(channelName: String): Option[HttpPropagation] =
+    _propagationComponents.httpChannels.get(channelName)
+
+  /**
+    * Retrieves the default HTTP propagation channel. Configuration for this channel can be found under the
+    * kamon.propagation.channels.http configuration setting.
+    *
+    * @return The default HTTP propagation.
+    */
+  def defaultHttpPropagation(): HttpPropagation =
+    _defaultHttpPropagation
+
+
+
+  private def init(config: Config): Unit = synchronized {
+    _propagationComponents = ContextPropagation.Components.from(self.config, self)
+    _defaultHttpPropagation = _propagationComponents.httpChannels(ContextPropagation.DefaultHttpChannel)
+  }
+}
+
+object ContextPropagation {
+  val DefaultHttpChannel = "http"
+  val DefaultBinaryChannel = "binary"
+
+  case class Components(
+    httpChannels: Map[String, HttpPropagation]
+  )
+
+  object Components {
+
+    def from(config: Config, classLoading: ClassLoading): Components = {
+      val propagationConfig = config.getConfig("kamon.propagation")
+      val channels = propagationConfig.getConfig("channels").configurations
+
+      val httpChannels = Map.newBuilder[String, HttpPropagation]
+
+      channels.foreach {
+        case (channelName, channelConfig) => channelConfig.getString("type") match {
+          case "http" => httpChannels += (channelName -> HttpPropagation.from(channelConfig, classLoading))
+        }
+      }
+
+      Components(httpChannels.result())
+    }
+  }
+}