1 files changed, 100 insertions, 0 deletions
diff --git a/core-init/src/main/scala/xyz/driver/core/init/HttpApi.scala b/core-init/src/main/scala/xyz/driver/core/init/HttpApi.scala
new file mode 100644
index 0000000..81428bf
--- /dev/null
+++ b/core-init/src/main/scala/xyz/driver/core/init/HttpApi.scala
@@ -0,0 +1,100 @@
+package xyz.driver.core
+package init
+
+import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport
+import akka.http.scaladsl.server.{RequestContext, Route, RouteConcatenation}
+import spray.json.DefaultJsonProtocol._
+import spray.json._
+import xyz.driver.core.rest.Swagger
+import xyz.driver.core.rest.directives.Directives
+import akka.http.scaladsl.model.headers._
+import xyz.driver.core.reporting.Reporter.CausalRelation
+import xyz.driver.core.rest.headers.Traceparent
+
+import scala.collection.JavaConverters._
+
+/** Mixin trait that provides some well-known HTTP endpoints, diagnostic header injection and forwarding,
+  * and exposes an application-specific route that must be implemented by services.
+  * @see ProtobufApi
+  */
+trait HttpApi extends CloudServices with Directives with SprayJsonSupport { self =>
+
+  /** Route that handles the application's business logic.
+    * @group hooks
+    */
+  def applicationRoute: Route
+
+  /** Classes with Swagger annotations.
+    * @group hooks
+    */
+  def swaggerRouteClasses: Set[Class[_]]
+
+  private val healthRoute = path("health") {
+    complete(Map("status" -> "good").toJson)
+  }
+
+  private val versionRoute = path("version") {
+    complete(Map("name" -> self.name.toJson, "version" -> self.version.toJson).toJson)
+  }
+
+  private lazy val swaggerRoute = {
+    val generator = new Swagger(
+      "",
+      "https" :: "http" :: Nil,
+      self.version.getOrElse("<unknown>"),
+      swaggerRouteClasses,
+      config,
+      reporter
+    )
+    generator.routes ~ generator.swaggerUINew
+  }
+
+  private def cors(inner: Route): Route =
+    cors(
+      config.getStringList("application.cors.allowedOrigins").asScala.toSet,
+      xyz.driver.core.rest.AllowedHeaders
+    )(inner)
+
+  private def traced(inner: Route): Route = (ctx: RequestContext) => {
+    val tags = Map(
+      "service.version" -> version.getOrElse("<unknown>"),
+      // open tracing semantic tags
+      "span.kind"     -> "server",
+      "service"       -> name,
+      "http.url"      -> ctx.request.uri.toString,
+      "http.method"   -> ctx.request.method.value,
+      "peer.hostname" -> ctx.request.uri.authority.host.toString,
+      // google's tracing console provides extra search features if we define these tags
+      "/http/path"       -> ctx.request.uri.path.toString,
+      "/http/method"     -> ctx.request.method.value.toString,
+      "/http/url"        -> ctx.request.uri.toString,
+      "/http/user_agent" -> ctx.request.header[`User-Agent`].map(_.value).getOrElse("<unknown>")
+    )
+    val parent = ctx.request.header[Traceparent].map { header =>
+      header.spanContext -> CausalRelation.Child
+    }
+    reporter
+      .traceWithOptionalParentAsync(s"http_handle_rpc", tags, parent) { spanContext =>
+        val header = Traceparent(spanContext)
+        val withHeader = ctx.withRequest(
+          ctx.request
+            .removeHeader(header.name)
+            .addHeader(header)
+        )
+        inner(withHeader)
+      }
+  }
+
+  /** Extended route. */
+  override lazy val route: Route = traced(
+    cors(
+      RouteConcatenation.concat(
+        healthRoute,
+        versionRoute,
+        swaggerRoute,
+        applicationRoute
+      )
+    )
+  )
+
+}