Add unsafeRunServer method (#2050)

adapters/quick/src/main/scala/caliban/quick/package.scala

@@ -1,8 +1,8 @@
 package caliban
 
 import caliban.Configurator.ExecutionConfiguration
+import zio._
 import zio.http._
-import zio.{ RIO, Trace, ZIO }
 
 package object quick {
 
@@ -68,6 +68,49 @@ package object quick {
       trace: Trace
     ): ZIO[R, CalibanError.ValidationError, RequestHandler[R, Response]] =
       gql.interpreter.map(QuickAdapter(_).configure(config).handler)
+
+    /**
+     * Unsafe API which allows running the server impurely
+     */
+    def unsafe: UnsafeApi[R] = gql.interpreterEither.fold(throw _, new UnsafeApi(_))
   }
 
+  final class UnsafeApi[R](
+    interpreter: GraphQLInterpreter[R, Any],
+    executionConfig: ExecutionConfiguration = ExecutionConfiguration()
+  ) {
+
+    /**
+     * Convenience method for impurely running the server.
+     *
+     * Useful for scripts / demos / showing off Caliban to your colleagues etc.
+     *
+     * Note that in order to call this method, you need to provide all dependencies required by the GraphQL environment. You can do that by passing a `ZLayer` to [[provideLayer]].
+     */
+    def runServer(
+      port: Int = 8080,
+      apiPath: String = "/graphql",
+      graphiqlPath: Option[String] = Some("/graphiql"),
+      uploadPath: Option[String] = None
+    )(implicit trace: Trace, ev: Any =:= R): Unit = {
+      val run: RIO[R, Nothing] =
+        QuickAdapter(interpreter)
+          .configure(executionConfig)
+          .runServer(port, apiPath, graphiqlPath, uploadPath)
+
+      ZIOApp.fromZIO(run.asInstanceOf[RIO[Any, Nothing]]).main(Array.empty)
+    }
+
+    def provideLayer(layer: ZLayer[Any, Any, R]): UnsafeApi[Any] =
+      new UnsafeApi(interpreter.provideLayer(layer))
+
+    def provideSomeLayer[R0](layer: ZLayer[R0, Any, R])(implicit tag: Tag[R]): UnsafeApi[R0] =
+      new UnsafeApi(interpreter.provideSomeLayer(layer))
+
+    def configure(cfg: ExecutionConfiguration): UnsafeApi[R] =
+      new UnsafeApi(interpreter, cfg)
+
+    def configureWith(cfg: ExecutionConfiguration => ExecutionConfiguration): UnsafeApi[R] =
+      new UnsafeApi(interpreter, cfg(executionConfig))
+  }
 }

core/src/main/scala/caliban/GraphQL.scala

@@ -59,12 +59,10 @@ trait GraphQL[-R] { self =>
    * adding some middleware around the query execution.
    * Fails with a [[caliban.CalibanError.ValidationError]] if the schema is invalid.
    */
-  final def interpreter(implicit trace: Trace): IO[ValidationError, GraphQLInterpreter[R, CalibanError]] = {
-    val i = cachedInterpreter
-    ZIO.fromEither(i)
-  }
+  final def interpreter(implicit trace: Trace): IO[ValidationError, GraphQLInterpreter[R, CalibanError]] =
+    ZIO.fromEither(interpreterEither)
 
-  private lazy val cachedInterpreter =
+  private[caliban] final lazy val interpreterEither =
     Validator.validateSchemaEither(schemaBuilder).map { schema =>
       new GraphQLInterpreter[R, CalibanError] {
         private val rootType =