Add supplementary comments

Author: style95

common/scala/src/main/scala/org/apache/openwhisk/core/connector/Message.scala

@@ -427,6 +427,23 @@ object EventMessage extends DefaultJsonProtocol {
   def parse(msg: String) = Try(format.read(msg.parseJson))
 }
 
+/**
+ * This case class is used when retrieving the snapshot of the queue status from the scheduler at a certain moment.
+ * This is useful to figure out the internal status when any issue happens.
+ * The following would be an example result.
+ *
+ * [
+ * ...
+ *    {
+ *       "data": "RunningData",
+ *       "fqn": "whisk.system/elasticsearch/[email protected]",
+ *       "invocationNamespace": "style95",
+ *       "status": "Running",
+ *       "waitingActivation": 1
+ *    },
+ * ...
+ * ]
+ */
 object StatusQuery
 case class StatusData(invocationNamespace: String, fqn: String, waitingActivation: Int, status: String, data: String)
     extends Message {

core/scheduler/src/main/scala/org/apache/openwhisk/core/scheduler/Scheduler.scala

@@ -93,7 +93,7 @@ class Scheduler(schedulerId: SchedulerInstanceId, schedulerEndpoints: SchedulerE
   }
 
   // other components don't need to shutdown gracefully
-  override def shutdown(): Unit = {
+  override def disable(): Unit = {
     logging.info(this, s"Gracefully shutting down the scheduler")
     // TODO: TBD, gracefully shut down the container manager and queue manager
   }
@@ -116,12 +116,24 @@ class Scheduler(schedulerId: SchedulerInstanceId, schedulerEndpoints: SchedulerE
 
   private val etcdWorkerFactory = "" // TODO: TBD
 
+  /**
+   * This component is in charge of storing data to ETCD.
+   * Even if any error happens we can assume the data will be eventually available in the ETCD by this component.
+   */
   val dataManagementService = "" // TODO: TBD
 
   val creationJobManagerFactory = "" // TODO: TBD
 
+  /**
+   * This component is responsible for creating containers for a given action.
+   * It relies on the creationJobManager to manage the container creation job.
+   */
   val containerManager = "" // TODO: TBD
 
+  /**
+   * This is a factory to create memory queues.
+   * In the new architecture, each action is given its own dedicated queue.
+   */
   val memoryQueueFactory = "" // TODO: TBD
 
   val schedulerConsumer = msgProvider.getConsumer(
@@ -133,6 +145,9 @@ class Scheduler(schedulerId: SchedulerInstanceId, schedulerEndpoints: SchedulerE
 
   implicit val trasnid = TransactionId.containerCreation
 
+  /**
+   * This is one of the major components which take charge of managing queues and coordinating requests among the scheduler, controllers, and invokers.
+   */
   val queueManager = "" // TODO: TBD
 
   //val serviceHandlers: HttpRequest => Future[HttpResponse] = ActivationServiceHandler.apply(ActivationServiceImpl())  TODO: TBD
@@ -147,13 +162,16 @@ trait SchedulerCore {
 
   def getQueueStatusData: Future[List[String]] // TODO: Change to the real data class other than just string
 
-  def shutdown(): Unit
+  def disable(): Unit
 }
 
 object Scheduler {
 
   protected val protocol = loadConfigOrThrow[String]("whisk.scheduler.protocol")
 
+  /**
+   * The scheduler has two ports, one for akka-remote and the other for akka-grpc.
+   */
   def requiredProperties =
     Map(
       servicePort -> 8080.toString,

core/scheduler/src/main/scala/org/apache/openwhisk/core/scheduler/SchedulerServer.scala

@@ -43,7 +43,7 @@ class SchedulerServer(scheduler: SchedulerCore, systemUsername: String, systemPa
       case Some(BasicHttpCredentials(username, password)) if username == systemUsername && password == systemPassword =>
         (path("disable") & post) {
           logger.warn(this, "Scheduler is disabled")
-          scheduler.shutdown()
+          scheduler.disable()
           complete("scheduler disabled")
         }
       case _ =>