telemetry: Undo Stats rework

Effectively reverting cf4bd92611 and
passing a pointer to the relevant com.Counter to the history sync.

cmd/icingadb/main.go

@@ -186,7 +186,7 @@ func run() int {
 			}
 
 			callbackCfg = &history.SyncCallbackConf{
-				Name:         "notifications_sync",
+				StatPtr:      &telemetry.Stats.NotificationSync,
 				KeyStructPtr: notifications.SyncKeyStructPtrs,
 				Fn:           notificationsSource.Submit,
 			}

pkg/icingadb/history/retention.go

@@ -230,7 +230,7 @@ func (r *Retention) Start(ctx context.Context) error {
 
 			deleted, err := stmt.CleanupOlderThan(
 				ctx, r.db, e.Id, r.count, olderThan,
-				database.OnSuccessIncrement[struct{}](telemetry.Stats.Get(telemetry.StatHistoryCleanup)),
+				database.OnSuccessIncrement[struct{}](&telemetry.Stats.HistoryCleanup),
 			)
 			if err != nil {
 				select {

pkg/icingadb/history/sync.go

@@ -32,8 +32,8 @@ type Sync struct {
 
 // SyncCallbackConf configures a callback stage given to Sync.Sync.
 type SyncCallbackConf struct {
-	// Name of this callback, used in [telemetry.Stats].
-	Name string
+	// StatPtr refers a [com.Counter] from the [telemetry.Stats] struct, e.g., Stats.NotificationSync.
+	StatPtr *com.Counter
 	// KeyStructPtr says which pipeline keys should be mapped to which type, identified by a struct pointer. If
 	// a key is missing from the map, it will not be used for the callback.
 	KeyStructPtr map[string]any
@@ -60,7 +60,7 @@ func (s Sync) Sync(ctx context.Context, callbackCfg *SyncCallbackConf) error {
 		callbackStageFn = makeSortedCallbackStageFunc(
 			ctx,
 			s.logger,
-			callbackCfg.Name,
+			callbackCfg.StatPtr,
 			callbackCfg.KeyStructPtr,
 			callbackCfg.Fn)
 	}
@@ -417,7 +417,7 @@ func countElementStage(ctx context.Context, _ Sync, _ string, in <-chan redis.XM
 				return nil
 			}
 
-			telemetry.Stats.Get(telemetry.StatHistory).Add(1)
+			telemetry.Stats.History.Add(1)
 			out <- msg
 
 		case <-ctx.Done():
@@ -440,12 +440,12 @@ func countElementStage(ctx context.Context, _ Sync, _ string, in <-chan redis.XM
 // If the callback function returns false, the message will be retried after an increasing backoff. All subsequent
 // messages will wait until this one succeeds.
 //
-// For each successfully submitted message, the telemetry stat named after this callback is incremented. Thus, a delta
-// between [telemetry.StatHistory] and this stat indicates blocking callbacks.
+// For each successfully submitted message, the telemetry stat referenced via a pointer s incremented. Thus, a delta
+// between telemetry.Stats.History and this stat indicates blocking callbacks.
 func makeSortedCallbackStageFunc(
 	ctx context.Context,
 	logger *logging.Logger,
-	name string,
+	statPtr *com.Counter,
 	keyStructPtrs map[string]any,
 	fn func(database.Entity) bool,
 ) stageFunc {
@@ -490,7 +490,7 @@ func makeSortedCallbackStageFunc(
 
 		success := fn(entity)
 		if success {
-			telemetry.Stats.Get(name).Add(1)
+			statPtr.Add(1)
 		}
 		return success
 	}

pkg/icingadb/overdue/sync.go

@@ -219,7 +219,7 @@ func (s Sync) updateOverdue(
 	}
 
 	counter.Add(uint64(len(ids)))
-	telemetry.Stats.Get(telemetry.StatOverdue).Add(uint64(len(ids)))
+	telemetry.Stats.Overdue.Add(uint64(len(ids)))
 
 	var op func(ctx context.Context, key string, members ...any) *redis.IntCmd
 	if overdue {

pkg/icingadb/runtime_updates.go

@@ -184,7 +184,7 @@ func (r *RuntimeUpdates) Sync(
 			return r.db.NamedBulkExec(
 				ctx, cvStmt, cvCount, sem, customvars, database.SplitOnDupId[database.Entity],
 				database.OnSuccessIncrement[database.Entity](&counter),
-				database.OnSuccessIncrement[database.Entity](telemetry.Stats.Get(telemetry.StatConfig)),
+				database.OnSuccessIncrement[database.Entity](&telemetry.Stats.Config),
 			)
 		})
 
@@ -204,7 +204,7 @@ func (r *RuntimeUpdates) Sync(
 			return r.db.NamedBulkExec(
 				ctx, cvFlatStmt, cvFlatCount, sem, flatCustomvars,
 				database.SplitOnDupId[database.Entity], database.OnSuccessIncrement[database.Entity](&counter),
-				database.OnSuccessIncrement[database.Entity](telemetry.Stats.Get(telemetry.StatConfig)),
+				database.OnSuccessIncrement[database.Entity](&telemetry.Stats.Config),
 			)
 		})
 

pkg/icingadb/sync.go

@@ -225,8 +225,8 @@ func (s Sync) SyncCustomvars(ctx context.Context) error {
 func getCounterForEntity(e database.Entity) *com.Counter {
 	switch e.(type) {
 	case *v1.HostState, *v1.ServiceState:
-		return telemetry.Stats.Get(telemetry.StatState)
+		return &telemetry.Stats.State
 	default:
-		return telemetry.Stats.Get(telemetry.StatConfig)
+		return &telemetry.Stats.Config
 	}
 }

pkg/icingaredis/telemetry/stats.go

@@ -2,74 +2,42 @@ package telemetry
 
 import (
 	"context"
-	"fmt"
 	"github.com/icinga/icinga-go-library/com"
 	"github.com/icinga/icinga-go-library/logging"
 	"github.com/icinga/icinga-go-library/periodic"
 	"github.com/icinga/icinga-go-library/redis"
 	"github.com/icinga/icinga-go-library/utils"
 	"go.uber.org/zap"
-	"iter"
 	"strconv"
-	"sync"
 	"time"
 )
 
-// StatsKeeper holds multiple [com.Counter] values by name, to be used for statistics in WriteStats.
-type StatsKeeper struct {
-	m sync.Map
+var Stats struct {
+	// Config & co. are to be increased by the T sync once for every T object synced.
+	Config           com.Counter
+	State            com.Counter
+	History          com.Counter
+	Callback         com.Counter
+	Overdue          com.Counter
+	HistoryCleanup   com.Counter
+	NotificationSync com.Counter
 }
 
-// Get or create a [com.Counter] by its name.
-func (statsKeeper *StatsKeeper) Get(key string) *com.Counter {
-	ctrAny, _ := statsKeeper.m.LoadOrStore(key, &com.Counter{})
-
-	ctr, ok := ctrAny.(*com.Counter)
-	if !ok {
-		// Should not happen unless someone messes with the internal map.
-		panic(fmt.Sprintf(
-			"StatsKeeper.Get(%q) returned something of type %T, not *com.Counter",
-			key, ctrAny))
-	}
-
-	return ctr
-}
-
-// Iterator over all keys and their [com.Counter].
-func (statsKeeper *StatsKeeper) Iterator() iter.Seq2[string, *com.Counter] {
-	return func(yield func(string, *com.Counter) bool) {
-		statsKeeper.m.Range(func(keyAny, ctrAny any) bool {
-			key, keyOk := keyAny.(string)
-			ctr, ctrOk := ctrAny.(*com.Counter)
-			if !keyOk || !ctrOk {
-				// Should not happen unless someone messes with the internal map.
-				panic(fmt.Sprintf(
-					"iterating StatsKeeper on key %q got types (%T, %T), not (string, *com.Counter)",
-					keyAny, keyAny, ctrAny))
-			}
-
-			return yield(key, ctr)
-		})
-	}
-}
-
-// Stats is the singleton StatsKeeper to be used to access a [com.Counter].
-var Stats = &StatsKeeper{}
-
-// Keys for different well known Stats entries.
-const (
-	StatConfig         = "config_sync"
-	StatState          = "state_sync"
-	StatHistory        = "history_sync"
-	StatOverdue        = "overdue_sync"
-	StatHistoryCleanup = "history_cleanup"
-)
-
 // WriteStats periodically forwards Stats to Redis for being monitored by Icinga 2.
 func WriteStats(ctx context.Context, client *redis.Client, logger *logging.Logger) {
+	counters := map[string]*com.Counter{
+		"config_sync":       &Stats.Config,
+		"state_sync":        &Stats.State,
+		"history_sync":      &Stats.History,
+		"callback_sync":     &Stats.Callback,
+		"overdue_sync":      &Stats.Overdue,
+		"history_cleanup":   &Stats.HistoryCleanup,
+		"notification_sync": &Stats.NotificationSync,
+	}
+
 	periodic.Start(ctx, time.Second, func(_ periodic.Tick) {
 		var data []string
-		for kind, counter := range Stats.Iterator() {
+		for kind, counter := range counters {
 			if cnt := counter.Reset(); cnt > 0 {
 				data = append(data, kind, strconv.FormatUint(cnt, 10))
 			}

pkg/icingaredis/telemetry/stats_test.go

@@ -1,44 +0,0 @@
-package telemetry
-
-import (
-	"github.com/stretchr/testify/assert"
-	"testing"
-)
-
-func TestStatsKeeper(t *testing.T) {
-	desiredState := map[string]uint64{
-		"foo": 23,
-		"bar": 42,
-		"baz": 0,
-	}
-
-	stats := &StatsKeeper{}
-
-	// Populate based on desiredState
-	for key, counterValue := range desiredState {
-		ctr := stats.Get(key)
-		ctr.Add(counterValue)
-	}
-
-	// Check if desiredState is set
-	for key, counterValue := range desiredState {
-		ctr := stats.Get(key)
-		assert.Equal(t, counterValue, ctr.Val())
-	}
-
-	// Get reference, change value, compare
-	fooKey := "foo"
-	fooCtr := stats.Get(fooKey)
-	assert.Equal(t, desiredState[fooKey], fooCtr.Reset())
-	assert.Equal(t, uint64(0), fooCtr.Val())
-	assert.Equal(t, uint64(0), stats.Get(fooKey).Val())
-	fooCtr.Add(desiredState[fooKey])
-	assert.Equal(t, desiredState[fooKey], stats.Get(fooKey).Val())
-
-	// Range over
-	for key, ctr := range stats.Iterator() {
-		desired, ok := desiredState[key]
-		assert.True(t, ok)
-		assert.Equal(t, desired, ctr.Val())
-	}
-}