when server restarts, we should unlock all locked jobs, and set their status to failed

make sure we can customize the limit value for Background Job query.

fixes #267

backend/pkg/database/sqlite_repository.go

@@ -106,6 +106,12 @@ func NewRepository(appConfig config.Interface, globalLogger logrus.FieldLogger,
 		return nil, fmt.Errorf("Failed to create admin user! - %v", err)
 	}
 
+	//fail any Locked jobs. This is necessary because the job may have been locked by a process that was killed.
+	err = fastenRepo.CancelAllLockedBackgroundJobsAndFail()
+	if err != nil {
+		return nil, err
+	}
+
 	return &fastenRepo, nil
 }
 
@@ -1146,6 +1152,19 @@ func (sr *SqliteRepository) BackgroundJobCheckpoint(ctx context.Context, checkpo
 
 }
 
+// when server restarts, we should unlock all locked jobs, and set their status to failed
+// SECURITY: this is global, and effects all users.
+func (sr *SqliteRepository) CancelAllLockedBackgroundJobsAndFail() error {
+	now := time.Now()
+	return sr.GormClient.
+		Where(models.BackgroundJob{JobStatus: pkg.BackgroundJobStatusLocked}).
+		Updates(models.BackgroundJob{
+			JobStatus: pkg.BackgroundJobStatusFailed,
+			DoneTime:  &now,
+		}).Error
+
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // Utilities
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

backend/pkg/web/handler/background_jobs.go

@@ -151,8 +151,21 @@ func ListBackgroundJobs(c *gin.Context) {
 	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
 	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)
 
-	backgroundJobQueryOptions := models.BackgroundJobQueryOptions{
-		Limit: pkg.ResourceListPageSize,
+	backgroundJobQueryOptions := models.BackgroundJobQueryOptions{}
+	if len(c.Query("limit")) == 0 {
+		backgroundJobQueryOptions.Limit = pkg.ResourceListPageSize
+	} else {
+		limit, err := strconv.Atoi(c.Query("limit"))
+		if err != nil {
+			logger.Errorln("An error occurred while calculating limit", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"success": false})
+			return
+		}
+		if limit == 0 {
+			backgroundJobQueryOptions.Limit = pkg.ResourceListPageSize
+		} else {
+			backgroundJobQueryOptions.Limit = limit
+		}
 	}
 	if len(c.Query("jobType")) > 0 {
 		jobType := pkg.BackgroundJobType(c.Query("jobType"))