limit collection lookups and other small refactoring

* adds error handling for collection lookup (#216)

beszel/internal/hub/hub.go

@@ -42,6 +42,8 @@ type Hub struct {
 	am                *alerts.AlertManager
 	um                *users.UserManager
 	rm                *records.RecordManager
+	systemStats       *models.Collection
+	containerStats    *models.Collection
 }
 
 func NewHub(app *pocketbase.PocketBase) *Hub {
@@ -125,7 +127,11 @@ func (h *Hub) Run() {
 		// delete old records once every hour
 		scheduler.MustAdd("delete old records", "8 * * * *", h.rm.DeleteOldRecords)
 		// create longer records every 10 minutes
-		scheduler.MustAdd("create longer records", "*/10 * * * *", h.rm.CreateLongerRecords)
+		scheduler.MustAdd("create longer records", "*/10 * * * *", func() {
+			if systemStats, containerStats, err := h.getCollections(); err == nil {
+				h.rm.CreateLongerRecords([]*models.Collection{systemStats, containerStats})
+			}
+		})
 		scheduler.Start()
 		return nil
 	})
@@ -286,37 +292,61 @@ func (h *Hub) updateSystem(record *models.Record) {
 		return
 	}
 	// update system record
+	dao := h.app.Dao()
 	record.Set("status", "up")
 	record.Set("info", systemData.Info)
-	if err := h.app.Dao().SaveRecord(record); err != nil {
+	if err := dao.SaveRecord(record); err != nil {
 		h.app.Logger().Error("Failed to update record: ", "err", err.Error())
 	}
-	// add new system_stats record
-	system_stats, _ := h.app.Dao().FindCollectionByNameOrId("system_stats")
-	systemStatsRecord := models.NewRecord(system_stats)
-	systemStatsRecord.Set("system", record.Id)
-	systemStatsRecord.Set("stats", systemData.Stats)
-	systemStatsRecord.Set("type", "1m")
-	if err := h.app.Dao().SaveRecord(systemStatsRecord); err != nil {
-		h.app.Logger().Error("Failed to save record: ", "err", err.Error())
-	}
-	// add new container_stats record
-	if len(systemData.Containers) > 0 {
-		container_stats, _ := h.app.Dao().FindCollectionByNameOrId("container_stats")
-		containerStatsRecord := models.NewRecord(container_stats)
-		containerStatsRecord.Set("system", record.Id)
-		containerStatsRecord.Set("stats", systemData.Containers)
-		containerStatsRecord.Set("type", "1m")
-		if err := h.app.Dao().SaveRecord(containerStatsRecord); err != nil {
+	// add system_stats and container_stats records
+	if systemStats, containerStats, err := h.getCollections(); err != nil {
+		h.app.Logger().Error("Failed to get collections: ", "err", err.Error())
+	} else {
+		// add new system_stats record
+		systemStatsRecord := models.NewRecord(systemStats)
+		systemStatsRecord.Set("system", record.Id)
+		systemStatsRecord.Set("stats", systemData.Stats)
+		systemStatsRecord.Set("type", "1m")
+		if err := dao.SaveRecord(systemStatsRecord); err != nil {
 			h.app.Logger().Error("Failed to save record: ", "err", err.Error())
 		}
+		// add new container_stats record
+		if len(systemData.Containers) > 0 {
+			containerStatsRecord := models.NewRecord(containerStats)
+			containerStatsRecord.Set("system", record.Id)
+			containerStatsRecord.Set("stats", systemData.Containers)
+			containerStatsRecord.Set("type", "1m")
+			if err := dao.SaveRecord(containerStatsRecord); err != nil {
+				h.app.Logger().Error("Failed to save record: ", "err", err.Error())
+			}
+		}
 	}
+
 	// system info alerts (todo: extra fs alerts)
 	if err := h.am.HandleSystemAlerts(record, systemData.Info, systemData.Stats.Temperatures, systemData.Stats.ExtraFs); err != nil {
 		h.app.Logger().Error("System alerts error", "err", err.Error())
 	}
 }
 
+// return system_stats and container_stats collections
+func (h *Hub) getCollections() (*models.Collection, *models.Collection, error) {
+	if h.systemStats == nil {
+		systemStats, err := h.app.Dao().FindCollectionByNameOrId("system_stats")
+		if err != nil {
+			return nil, nil, err
+		}
+		h.systemStats = systemStats
+	}
+	if h.containerStats == nil {
+		containerStats, err := h.app.Dao().FindCollectionByNameOrId("container_stats")
+		if err != nil {
+			return nil, nil, err
+		}
+		h.containerStats = containerStats
+	}
+	return h.systemStats, h.containerStats, nil
+}
+
 // set system to specified status and save record
 func (h *Hub) updateSystemStatus(record *models.Record, status string) {
 	if record.GetString("status") != status {

beszel/internal/records/records.go

@@ -32,7 +32,7 @@ type RecordDeletionData struct {
 	retention  time.Duration
 }
 
-type RecordStats []*struct {
+type RecordStats []struct {
 	Stats []byte `db:"stats"`
 }
 
@@ -41,9 +41,9 @@ func NewRecordManager(app *pocketbase.PocketBase) *RecordManager {
 }
 
 // Create longer records by averaging shorter records
-func (rm *RecordManager) CreateLongerRecords() {
+func (rm *RecordManager) CreateLongerRecords(collections []*models.Collection) {
 	// start := time.Now()
-	recordData := []LongerRecordData{
+	longerRecordData := []LongerRecordData{
 		{
 			shorterType: "1m",
 			// change to 9 from 10 to allow edge case timing or short pauses
@@ -78,17 +78,11 @@ func (rm *RecordManager) CreateLongerRecords() {
 			return err
 		}
 
-		// need *models.Collection to create a new record with models.NewRecord
-		collections := map[string]*models.Collection{}
-		for _, collectionName := range []string{"system_stats", "container_stats"} {
-			collection, _ := txDao.FindCollectionByNameOrId(collectionName)
-			collections[collectionName] = collection
-		}
-
 		// loop through all active systems, time periods, and collections
 		for _, system := range activeSystems {
 			// log.Println("processing system", system.GetString("name"))
-			for _, recordData := range recordData {
+			for i := range longerRecordData {
+				recordData := longerRecordData[i]
 				// log.Println("processing longer record type", recordData.longerType)
 				// add one minute padding for longer records because they are created slightly later than the job start time
 				longerRecordPeriod := time.Now().UTC().Add(recordData.longerTimeDuration + time.Minute)
@@ -165,8 +159,8 @@ func (rm *RecordManager) AverageSystemStats(records RecordStats) system.Stats {
 	tempCount := float64(0)
 
 	var stats system.Stats
-	for _, record := range records {
-		json.Unmarshal(record.Stats, &stats)
+	for i := range records {
+		json.Unmarshal(records[i].Stats, &stats)
 		sum.Cpu += stats.Cpu
 		sum.Mem += stats.Mem
 		sum.MemUsed += stats.MemUsed
@@ -268,13 +262,14 @@ func (rm *RecordManager) AverageContainerStats(records RecordStats) []container.
 	count := float64(len(records))
 
 	var containerStats []container.Stats
-	for _, record := range records {
+	for i := range records {
 		// Reset the slice length to 0, but keep the capacity
 		containerStats = containerStats[:0]
-		if err := json.Unmarshal(record.Stats, &containerStats); err != nil {
+		if err := json.Unmarshal(records[i].Stats, &containerStats); err != nil {
 			return []container.Stats{}
 		}
-		for _, stat := range containerStats {
+		for i := range containerStats {
+			stat := containerStats[i]
 			if _, ok := sums[stat.Name]; !ok {
 				sums[stat.Name] = &container.Stats{Name: stat.Name}
 			}