Refactor PeerFinder.peerConnectionScheduler() into method (#5377)

node/src/main/scala/org/bitcoins/node/PeerFinder.scala

@@ -112,7 +112,9 @@ case class PeerFinder(
 
   private val isConnectionSchedulerRunning = new AtomicBoolean(false)
 
-  private lazy val peerConnectionScheduler: Cancellable =
+  private[this] var peerConnectionCancellableOpt: Option[Cancellable] = None
+
+  private def peerConnectionScheduler(): Cancellable = {
     system.scheduler.scheduleWithFixedDelay(
       initialDelay = initialDelay,
       delay = nodeAppConfig.tryNextPeersInterval) { () =>
@@ -148,8 +150,10 @@ case class PeerFinder(
         }
       }
     }
+  }
 
   override def start(): Future[PeerFinder] = {
+    if (!isStarted.get()) {
       logger.info(
         s"Starting PeerFinder initialDelay=${initialDelay} paramPeers=$paramPeers")
       val start = System.currentTimeMillis()
@@ -166,7 +170,7 @@ case class PeerFinder(
           _peersToTry.pushAll(getPeersFromResources)
           _peersToTry.pushAll(dbNonCf)
           _peersToTry.pushAll(dbCf, priority = 1)
-        peerConnectionScheduler //start scheduler
+          peerConnectionCancellableOpt = Some(peerConnectionScheduler())
 
           this
         }
@@ -174,7 +178,7 @@ case class PeerFinder(
         startedF
       } else {
         logger.info("Peer discovery disabled.")
-      peerConnectionScheduler //start scheduler
+        peerConnectionCancellableOpt = Some(peerConnectionScheduler())
         Future.successful(this)
       }
 
@@ -183,6 +187,10 @@ case class PeerFinder(
         _ = logger.info(
           s"Done starting PeerFinder, it took ${System.currentTimeMillis() - start}ms")
       } yield peerFinder
+    } else {
+      logger.warn(s"PeerFinder already started")
+      Future.successful(this)
+    }
   }
 
   def reconnect(peer: Peer): Future[Unit] = {
@@ -197,10 +205,12 @@ case class PeerFinder(
   }
 
   override def stop(): Future[PeerFinder] = {
+    if (isStarted.get()) {
       logger.info(s"Stopping PeerFinder")
       isStarted.set(false)
       //stop scheduler
-    peerConnectionScheduler.cancel()
+      peerConnectionCancellableOpt.map(_.cancel())
+      peerConnectionCancellableOpt = None
       //delete try queue
       _peersToTry.clear()
 
@@ -216,10 +226,16 @@ case class PeerFinder(
       }
 
       stopF.failed.foreach { e =>
-      logger.error(s"Failed to stop peer finder. Peers: ${_peerData.map(_._1)}",
+        logger.error(
+          s"Failed to stop peer finder. Peers: ${_peerData.map(_._1)}",
           e)
       }
       stopF
+    } else {
+      logger.warn(s"PeerFinder already stopped")
+      Future.successful(this)
+    }
+
   }
 
   /** creates and initialises a new test peer */