server: add missing db.Close calls before returning (#541)

It's better to always close the db before exit, so we will be noticed
when any error happens. Otherwise, serious errors can silently happen,
e.g, corrupted db, pending write missing ...

Fixes #538

server/start.go

@@ -164,6 +164,11 @@ func startStandAlone(ctx *server.Context, appCreator types.AppCreator) error {
 	if err != nil {
 		return err
 	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			ctx.Logger.With("error", err).Error("error closing db")
+		}
+	}()
 
 	traceWriterFile := ctx.Viper.GetString(srvflags.TraceStore)
 	traceWriter, err := openTraceWriter(traceWriterFile)
@@ -226,6 +231,11 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 		logger.Error("failed to open DB", "error", err.Error())
 		return err
 	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			ctx.Logger.With("error", err).Error("error closing db")
+		}
+	}()
 
 	traceWriter, err := openTraceWriter(traceWriterFile)
 	if err != nil {