initial commit

2025-07-10 00:44:54 -06:00
commit 49a0f1d403
20 changed files with 3041 additions and 0 deletions
@@ -0,0 +1,67 @@
+package cache
+
+import (
+	"github.com/coredns/coredns/plugin"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	// cacheSize is total elements in the cache by cache type.
+	cacheSize = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "entries",
+		Help:      "The number of elements in the cache.",
+	}, []string{"server", "type", "zones", "view"})
+	// cacheRequests is a counter of all requests through the cache.
+	cacheRequests = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "requests_total",
+		Help:      "The count of cache requests.",
+	}, []string{"server", "zones", "view"})
+	// cacheHits is counter of cache hits by cache type.
+	cacheHits = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "hits_total",
+		Help:      "The count of cache hits.",
+	}, []string{"server", "type", "zones", "view"})
+	// cacheMisses is the counter of cache misses. - Deprecated
+	cacheMisses = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "misses_total",
+		Help:      "The count of cache misses. Deprecated, derive misses from cache hits/requests counters.",
+	}, []string{"server", "zones", "view"})
+	// cachePrefetches is the number of time the cache has prefetched a cached item.
+	cachePrefetches = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "prefetch_total",
+		Help:      "The number of times the cache has prefetched a cached item.",
+	}, []string{"server", "zones", "view"})
+	// cacheDrops is the number responses that are not cached, because the reply is malformed.
+	cacheDrops = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "drops_total",
+		Help:      "The number responses that are not cached, because the reply is malformed.",
+	}, []string{"server", "zones", "view"})
+	// servedStale is the number of requests served from stale cache entries.
+	servedStale = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "served_stale_total",
+		Help:      "The number of requests served from stale cache entries.",
+	}, []string{"server", "zones", "view"})
+	// evictions is the counter of cache evictions.
+	evictions = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: plugin.Namespace,
+		Subsystem: "host_specific_cache",
+		Name:      "evictions_total",
+		Help:      "The count of cache evictions.",
+	}, []string{"server", "type", "zones", "view"})
+)