Tracked validator TTL (#14957)

* `TrackedValidatorsCache`: Implement a 1-hour TTL by uding `go-cache`.

* `TrackedValidatorsCache`: Add the `ItemCount` method.

* `TrackedValidatorsCache`: Add the `Indices` method.

* Add changelog.

* `TrackedValidatorsCache`: Add prometheus metrics.

* Update beacon-chain/cache/tracked_validators.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

---------

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

beacon-chain/cache/BUILD.bazel

@@ -84,6 +84,7 @@ go_test(
         "sync_committee_head_state_test.go",
         "sync_committee_test.go",
         "sync_subnet_ids_test.go",
+        "tracked_validators_test.go",
     ],
     embed = [":go_default_library"],
     deps = [

beacon-chain/cache/tracked_validators.go

@@ -1,49 +1,139 @@
 package cache
 
 import (
-	"sync"
+	"strconv"
+	"time"
 
+	"github.com/patrickmn/go-cache"
+	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/sirupsen/logrus"
 )
 
-type TrackedValidator struct {
-	Active       bool
-	FeeRecipient primitives.ExecutionAddress
-	Index        primitives.ValidatorIndex
-}
+const (
+	defaultExpiration = 1 * time.Hour
+	cleanupInterval   = 15 * time.Minute
+)
 
-type TrackedValidatorsCache struct {
-	sync.Mutex
-	trackedValidators map[primitives.ValidatorIndex]TrackedValidator
-}
+type (
+	TrackedValidator struct {
+		Active       bool
+		FeeRecipient primitives.ExecutionAddress
+		Index        primitives.ValidatorIndex
+	}
 
+	TrackedValidatorsCache struct {
+		trackedValidators cache.Cache
+	}
+)
+
+var (
+	// Metrics.
+	trackedValidatorsCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "tracked_validators_cache_miss",
+		Help: "The number of tracked validators requests that are not present in the cache.",
+	})
+
+	trackedValidatorsCacheTotal = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "tracked_validators_cache_total",
+		Help: "The total number of tracked validators requests in the cache.",
+	})
+
+	trackedValidatorsCacheCount = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "tracked_validators_cache_count",
+		Help: "The number of tracked validators in the cache.",
+	})
+)
+
+// NewTrackedValidatorsCache creates a new cache for tracking validators.
 func NewTrackedValidatorsCache() *TrackedValidatorsCache {
 	return &TrackedValidatorsCache{
-		trackedValidators: make(map[primitives.ValidatorIndex]TrackedValidator),
+		trackedValidators: *cache.New(defaultExpiration, cleanupInterval),
 	}
 }
 
+// Validator retrieves a tracked validator from the cache (if present).
 func (t *TrackedValidatorsCache) Validator(index primitives.ValidatorIndex) (TrackedValidator, bool) {
-	t.Lock()
-	defer t.Unlock()
-	val, ok := t.trackedValidators[index]
-	return val, ok
+	trackedValidatorsCacheTotal.Inc()
+
+	key := toCacheKey(index)
+	item, ok := t.trackedValidators.Get(key)
+	if !ok {
+		trackedValidatorsCacheMiss.Inc()
+		return TrackedValidator{}, false
+	}
+
+	val, ok := item.(TrackedValidator)
+	if !ok {
+		logrus.Errorf("Failed to cast tracked validator from cache, got unexpected item type %T", item)
+		return TrackedValidator{}, false
+	}
+
+	return val, true
 }
 
+// Set adds a tracked validator to the cache.
 func (t *TrackedValidatorsCache) Set(val TrackedValidator) {
-	t.Lock()
-	defer t.Unlock()
-	t.trackedValidators[val.Index] = val
+	key := toCacheKey(val.Index)
+	t.trackedValidators.Set(key, val, cache.DefaultExpiration)
 }
 
+// Delete removes a tracked validator from the cache.
 func (t *TrackedValidatorsCache) Prune() {
-	t.Lock()
-	defer t.Unlock()
-	t.trackedValidators = make(map[primitives.ValidatorIndex]TrackedValidator)
+	t.trackedValidators.Flush()
+	trackedValidatorsCacheCount.Set(0)
 }
 
+// Validating returns true if there are at least one tracked validators in the cache.
 func (t *TrackedValidatorsCache) Validating() bool {
-	t.Lock()
-	defer t.Unlock()
-	return len(t.trackedValidators) > 0
+	count := t.trackedValidators.ItemCount()
+	trackedValidatorsCacheCount.Set(float64(count))
+
+	return count > 0
+}
+
+// ItemCount returns the number of tracked validators in the cache.
+func (t *TrackedValidatorsCache) ItemCount() int {
+	count := t.trackedValidators.ItemCount()
+	trackedValidatorsCacheCount.Set(float64(count))
+
+	return count
+}
+
+// Indices returns a map of validator indices that are being tracked.
+func (t *TrackedValidatorsCache) Indices() map[primitives.ValidatorIndex]bool {
+	items := t.trackedValidators.Items()
+	count := len(items)
+	trackedValidatorsCacheCount.Set(float64(count))
+
+	indices := make(map[primitives.ValidatorIndex]bool, count)
+
+	for cacheKey := range items {
+		index, err := fromCacheKey(cacheKey)
+		if err != nil {
+			logrus.WithError(err).Error("Failed to get validator index from cache key")
+			continue
+		}
+
+		indices[index] = true
+	}
+
+	return indices
+}
+
+// toCacheKey creates a cache key from the validator index.
+func toCacheKey(validatorIndex primitives.ValidatorIndex) string {
+	return strconv.FormatUint(uint64(validatorIndex), 10)
+}
+
+// fromCacheKey gets the validator index from the cache key.
+func fromCacheKey(key string) (primitives.ValidatorIndex, error) {
+	validatorIndex, err := strconv.ParseUint(key, 10, 64)
+	if err != nil {
+		return 0, errors.Wrapf(err, "parse Uint: %s", key)
+	}
+
+	return primitives.ValidatorIndex(validatorIndex), nil
 }

beacon-chain/cache/tracked_validators_test.go

@@ -0,0 +1,79 @@
+package cache
+
+import (
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v5/testing/require"
+)
+
+func mapEqual(a, b map[primitives.ValidatorIndex]bool) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for k, v := range a {
+		if b[k] != v {
+			return false
+		}
+	}
+
+	return true
+}
+
+func TestTrackedValidatorsCache(t *testing.T) {
+	vc := NewTrackedValidatorsCache()
+
+	// No validators in cache.
+	require.Equal(t, 0, vc.ItemCount())
+	require.Equal(t, false, vc.Validating())
+	require.Equal(t, 0, len(vc.Indices()))
+
+	_, ok := vc.Validator(41)
+	require.Equal(t, false, ok)
+
+	// Add some validators (one twice).
+	v42Expected := TrackedValidator{Active: true, FeeRecipient: [20]byte{1}, Index: 42}
+	v43Expected := TrackedValidator{Active: false, FeeRecipient: [20]byte{2}, Index: 43}
+
+	vc.Set(v42Expected)
+	vc.Set(v43Expected)
+	vc.Set(v42Expected)
+
+	// Check if they are in the cache.
+	v42Actual, ok := vc.Validator(42)
+	require.Equal(t, true, ok)
+	require.Equal(t, v42Expected, v42Actual)
+
+	v43Actual, ok := vc.Validator(43)
+	require.Equal(t, true, ok)
+	require.Equal(t, v43Expected, v43Actual)
+
+	expected := map[primitives.ValidatorIndex]bool{42: true, 43: true}
+	actual := vc.Indices()
+	require.Equal(t, true, mapEqual(expected, actual))
+
+	// Check the item count and if the cache is validating.
+	require.Equal(t, 2, vc.ItemCount())
+	require.Equal(t, true, vc.Validating())
+
+	// Check if a non-existing validator is in the cache.
+	_, ok = vc.Validator(41)
+	require.Equal(t, false, ok)
+
+	// Prune the cache and test it.
+	vc.Prune()
+
+	_, ok = vc.Validator(41)
+	require.Equal(t, false, ok)
+
+	_, ok = vc.Validator(42)
+	require.Equal(t, false, ok)
+
+	_, ok = vc.Validator(43)
+	require.Equal(t, false, ok)
+
+	require.Equal(t, 0, vc.ItemCount())
+	require.Equal(t, false, vc.Validating())
+	require.Equal(t, 0, len(vc.Indices()))
+}

changelog/manu_tracked_validators_ttl.md

@@ -0,0 +1,8 @@
+### Added
+
+- Tracked validators cache: Added the `ItemCount` method.
+- Tracked validators cache: Added the `Indices` method.
+
+### Changed
+
+- Tracked validators cache: Remove validators from the cache if not seen after 1 hour.