Add database plugin to call garbage collection and close DB (#289)

* Add database plugin to call garbage collection and close DB on shutdown #284

* Adjust comment

packages/shutdown/order.go

 package shutdown
 
 const (
-	ShutdownPriorityTangle = iota
+	ShutdownPriorityDatabase = iota
+	ShutdownPriorityTangle
 	ShutdownPriorityRemoteLog
 	ShutdownPriorityAnalysis
 	ShutdownPriorityMetrics

pluginmgr/core/plugins.go

@@ -5,6 +5,7 @@ import (
 	"github.com/iotaledger/goshimmer/plugins/banner"
 	"github.com/iotaledger/goshimmer/plugins/cli"
 	"github.com/iotaledger/goshimmer/plugins/config"
+	"github.com/iotaledger/goshimmer/plugins/database"
 	"github.com/iotaledger/goshimmer/plugins/gossip"
 	"github.com/iotaledger/goshimmer/plugins/gracefulshutdown"
 	"github.com/iotaledger/goshimmer/plugins/logger"
@@ -20,6 +21,7 @@ var PLUGINS = node.Plugins(
 	logger.PLUGIN,
 	cli.PLUGIN,
 	portcheck.PLUGIN,
+	database.PLUGIN,
 	autopeering.PLUGIN,
 	tangle.PLUGIN,
 	gossip.PLUGIN,

plugins/database/plugin.go

+// database is a plugin that manages the badger database (e.g. garbage collection).
+package database
+
+import (
+	"time"
+
+	"github.com/iotaledger/hive.go/timeutil"
+
+	"github.com/iotaledger/goshimmer/packages/database"
+	"github.com/iotaledger/goshimmer/packages/shutdown"
+
+	"github.com/iotaledger/hive.go/daemon"
+	"github.com/iotaledger/hive.go/logger"
+	"github.com/iotaledger/hive.go/node"
+)
+
+const (
+	PLUGIN_NAME = "Database"
+)
+
+var (
+	PLUGIN = node.NewPlugin(PLUGIN_NAME, node.Enabled, configure, run)
+	log    *logger.Logger
+)
+
+func configure(plugin *node.Plugin) {
+	log = logger.NewLogger(PLUGIN_NAME)
+
+	_ = database.GetBadgerInstance()
+}
+
+func run(plugin *node.Plugin) {
+	daemon.BackgroundWorker(PLUGIN_NAME+"_GC", func(shutdownSignal <-chan struct{}) {
+		timeutil.Ticker(func() {
+			database.CleanupBadgerInstance(log)
+		}, 5*time.Minute, shutdownSignal)
+	}, shutdown.ShutdownPriorityBadgerGarbageCollection)
+
+	daemon.BackgroundWorker(PLUGIN_NAME, func(shutdownSignal <-chan struct{}) {
+		<-shutdownSignal
+		log.Infof("Syncing database to disk...")
+		database.GetBadgerInstance().Close()
+		log.Infof("Syncing database to disk... done")
+	}, shutdown.ShutdownPriorityDatabase)
+}