shutdown server gracefully

src/main/scala/lc/Main.scala

@@ -25,6 +25,15 @@ object LCFramework {
       playgroundEnabled = config.playgroundEnabled,
       corsHeader = config.corsHeader
     )
+
+    Runtime.getRuntime.addShutdownHook( new Thread {
+        override def run(): Unit = {
+          println("Shutting down gracefully...")
+          backgroundTask.shutdown()
+        }
+      }
+    )
+
     server.start()
   }
 }

src/main/scala/lc/background/taskThread.scala

@@ -22,14 +22,18 @@ class BackgroundTask(config: Config, captchaManager: CaptchaManager) {
         val requiredCountPerCombination = Math.max(1, (config.throttle * 1.01) / allCombinations.size).toInt
 
         for (param <- allCombinations) {
-          val countExisting = captchaManager.getCount(param).getOrElse(0)
+          if (!shutdownInProgress) {
-          val countRequired = requiredCountPerCombination - countExisting
+            val countExisting = captchaManager.getCount(param).getOrElse(0)
-          if (countRequired > 0) {
+            val countRequired = requiredCountPerCombination - countExisting
-            val countCreate = Math.min(1.0 + requiredCountPerCombination/10.0, countRequired).toInt
+            if (countRequired > 0) {
-            println(s"Creating $countCreate of $countRequired captchas for $param")
+              val countCreate = Math.min(1.0 + requiredCountPerCombination/10.0, countRequired).toInt
+              println(s"Creating $countCreate of $countRequired captchas for $param")
 
-            for (i <- 0 until countCreate) {
+              for (i <- 0 until countCreate) {
-              captchaManager.generateChallenge(param)
+                if (!shutdownInProgress) {
+                  captchaManager.generateChallenge(param)
+                }
+              }
             }
           }
         }
@@ -62,9 +66,22 @@ class BackgroundTask(config: Config, captchaManager: CaptchaManager) {
     list(HelperFunctions.randomNumber(list.size))
   }
 
+  private val ex = new ScheduledThreadPoolExecutor(1)
+
   def beginThread(delay: Int): Unit = {
-    val ex = new ScheduledThreadPoolExecutor(1)
     ex.scheduleWithFixedDelay(task, 1, delay, TimeUnit.SECONDS)
   }
 
+  @volatile var shutdownInProgress = false
+
+  def shutdown(): Unit = {
+    println("  Shutting down background task...")
+    shutdownInProgress = true
+    ex.shutdown()
+    println("    Finished Shutting background task")
+    println("  Shutting down DB...")
+    Statements.tlStmts.get.shutdown.execute()
+    println("    Finished shutting down db")
+  }
+
 }

src/main/scala/lc/database/DB.scala

@@ -3,7 +3,7 @@ package lc.database
 import java.sql.{Connection, DriverManager, Statement}
 
 class DBConn() {
-  val con: Connection = DriverManager.getConnection("jdbc:h2:./data/H2/captcha2", "sa", "")
+  val con: Connection = DriverManager.getConnection("jdbc:h2:./data/H2/captcha2;MAX_COMPACT_TIME=8000;DB_CLOSE_ON_EXIT=FALSE", "sa", "")
 
   def getStatement(): Statement = {
     con.createStatement()

src/main/scala/lc/database/statements.scala

@@ -120,6 +120,14 @@ class Statements(dbConn: DBConn, maxAttempts: Int) {
     "SELECT * FROM mapId"
   )
 
+  val shutdown: PreparedStatement = dbConn.con.prepareStatement(
+    "SHUTDOWN"
+  )
+
+  val shutdownCompact: PreparedStatement = dbConn.con.prepareStatement(
+    "SHUTDOWN COMPACT"
+  )
+
 }
 
 object Statements {