add an identifier to caches (#5)

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/go-logr/logr v0.3.0
 	github.com/go-logr/zapr v0.3.0
 	github.com/golang/mock v1.4.4
+	github.com/google/uuid v1.1.1
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/mandelsoft/vfs v0.0.0-20201002134249-3c471f64a4d1
 	github.com/onsi/ginkgo v1.14.0

ociclient/cache/cache.go

@@ -28,8 +28,6 @@ type layeredCache struct {
 
 	baseFs    *FileSystem
 	overlayFs *FileSystem
-
-	basePath string
 }
 
 // NewCache creates a new cache with the given options.
@@ -61,21 +59,20 @@ func NewCache(log logr.Logger, options ...Option) (*layeredCache, error) {
 
 	//initialize metrics
 	baseCFs.WithMetrics(
-		metrics.CachedItems.WithLabelValues(opts.BasePath),
-		metrics.CacheDiskUsage.WithLabelValues(opts.BasePath),
-		metrics.CacheHitsDisk.WithLabelValues(opts.BasePath))
+		metrics.CachedItems.WithLabelValues(opts.UID),
+		metrics.CacheDiskUsage.WithLabelValues(opts.UID),
+		metrics.CacheHitsDisk.WithLabelValues(opts.UID))
 	if opts.InMemoryOverlay {
 		overlayCFs.WithMetrics(nil,
-			metrics.CacheMemoryUsage.WithLabelValues(opts.BasePath),
-			metrics.CacheHitsMemory.WithLabelValues(opts.BasePath))
+			metrics.CacheMemoryUsage.WithLabelValues(opts.UID),
+			metrics.CacheHitsMemory.WithLabelValues(opts.UID))
 	}
 
 	return &layeredCache{
 		log:       log,
 		mux:       sync.RWMutex{},
 		baseFs:    baseCFs,
 		overlayFs: overlayCFs,
-		basePath:  opts.BasePath,
 	}, nil
 }
 

ociclient/cache/cache_suite_test.go

@@ -53,6 +53,7 @@ var _ = Describe("Cache", func() {
 
 		Context("metrics", func() {
 			It("should read data from the in memory cache", func() {
+				uid := "unit-test"
 				dir, err := ioutil.TempDir(os.TempDir(), "test-")
 				Expect(err).ToNot(HaveOccurred())
 				defer func() {
@@ -64,7 +65,7 @@ var _ = Describe("Cache", func() {
 				metrics.CacheDiskUsage.Reset()
 				metrics.CacheMemoryUsage.Reset()
 
-				c, err := NewCache(testlog.NullLogger{}, WithBasePath(dir), WithInMemoryOverlay(true))
+				c, err := NewCache(testlog.NullLogger{}, WithBasePath(dir), WithInMemoryOverlay(true), WithUID(uid))
 				Expect(err).ToNot(HaveOccurred())
 				defer c.Close()
 
@@ -74,27 +75,27 @@ var _ = Describe("Cache", func() {
 				expected := `
 				# HELP ociclient_cache_items_total Total number of items currently cached by instance.
                 # TYPE ociclient_cache_items_total gauge
-                ociclient_cache_items_total{path="%s"} 1
+                ociclient_cache_items_total{id="%s"} 1
 				`
-				Expect(testutil.CollectAndCompare(metrics.CachedItems, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CachedItems, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_disk_hits_total Total number of hits for items cached on disk by an instance.
                 # TYPE ociclient_cache_disk_hits_total counter
-                ociclient_cache_disk_hits_total{path="%s"} 0
+                ociclient_cache_disk_hits_total{id="%s"} 0
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheHitsDisk, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheHitsDisk, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_memory_hits_total Total number of hits for items cached in memory by an instance.
                 # TYPE ociclient_cache_memory_hits_total counter
-                ociclient_cache_memory_hits_total{path="%s"} 0
+                ociclient_cache_memory_hits_total{id="%s"} 0
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheHitsMemory, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheHitsMemory, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_memory_usage_bytes Bytes in memory currently used by cache instance.
                 # TYPE ociclient_cache_memory_usage_bytes gauge
-                ociclient_cache_memory_usage_bytes{path="%s"} 0
+                ociclient_cache_memory_usage_bytes{id="%s"} 0
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheMemoryUsage, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheMemoryUsage, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 
 				r, err := c.Get(desc)
 				Expect(err).ToNot(HaveOccurred())
@@ -108,33 +109,33 @@ var _ = Describe("Cache", func() {
 				expected = `
 				# HELP ociclient_cache_items_total Total number of items currently cached by instance.
                 # TYPE ociclient_cache_items_total gauge
-                ociclient_cache_items_total{path="%s"} 1
+                ociclient_cache_items_total{id="%s"} 1
 				`
-				Expect(testutil.CollectAndCompare(metrics.CachedItems, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CachedItems, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_disk_usage_bytes Bytes on disk currently used by cache instance.
                 # TYPE ociclient_cache_disk_usage_bytes gauge
-                ociclient_cache_disk_usage_bytes{path="%s"} 10
+                ociclient_cache_disk_usage_bytes{id="%s"} 10
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheDiskUsage, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheDiskUsage, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_disk_hits_total Total number of hits for items cached on disk by an instance.
                 # TYPE ociclient_cache_disk_hits_total counter
-                ociclient_cache_disk_hits_total{path="%s"} 1
+                ociclient_cache_disk_hits_total{id="%s"} 1
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheHitsDisk, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheHitsDisk, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_memory_hits_total Total number of hits for items cached in memory by an instance.
                 # TYPE ociclient_cache_memory_hits_total counter
-                ociclient_cache_memory_hits_total{path="%s"} 1
+                ociclient_cache_memory_hits_total{id="%s"} 1
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheHitsMemory, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheHitsMemory, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 				expected = `
 				# HELP ociclient_cache_memory_usage_bytes Bytes in memory currently used by cache instance.
                 # TYPE ociclient_cache_memory_usage_bytes gauge
-                ociclient_cache_memory_usage_bytes{path="%s"} 10
+                ociclient_cache_memory_usage_bytes{id="%s"} 10
 				`
-				Expect(testutil.CollectAndCompare(metrics.CacheMemoryUsage, strings.NewReader(fmt.Sprintf(expected, dir)))).To(Succeed())
+				Expect(testutil.CollectAndCompare(metrics.CacheMemoryUsage, strings.NewReader(fmt.Sprintf(expected, uid)))).To(Succeed())
 			})
 		})
 	})

ociclient/cache/types.go

@@ -9,6 +9,8 @@ import (
 	"io"
 
 	ocispecv1 "github.com/opencontainers/image-spec/specs-go/v1"
+
+	"github.com/google/uuid"
 )
 
 var (
@@ -56,6 +58,9 @@ type Options struct {
 
 	// BaseGCConfig defines the garbage collection configuration for the in base cache.
 	BaseGCConfig GarbageCollectionConfiguration
+
+	// UID is the identity of a cache, if not specified a UID will be generated
+	UID string
 }
 
 // Option is the interface to specify different cache options
@@ -77,6 +82,10 @@ func (o *Options) ApplyDefaults() {
 	if o.InMemoryOverlay && len(o.InMemoryGCConfig.Size) == 0 {
 		o.InMemoryGCConfig.Size = "200Mi"
 	}
+
+	if len(o.UID) == 0 {
+		o.UID = uuid.New().String()
+	}
 }
 
 // WithInMemoryOverlay is the options to specify the usage of a in memory overlayFs
@@ -135,3 +144,10 @@ func (p WithInMemoryGCConfig) ApplyOption(options *Options) {
 	cfg := GarbageCollectionConfiguration(p)
 	cfg.Merge(&options.InMemoryGCConfig)
 }
+
+// WithUID is the option to give a cache an identity
+type WithUID string
+
+func (p WithUID) ApplyOption(options *Options) {
+	options.UID = string(p)
+}

ociclient/metrics/metrics.go

@@ -20,7 +20,7 @@ var (
 			Name:      "memory_usage_bytes",
 			Help:      "Bytes in memory currently used by cache instance.",
 		},
-		[]string{"path"},
+		[]string{"id"},
 	)
 
 	// CacheDiskUsage discloses disk used by caches
@@ -31,7 +31,7 @@ var (
 			Name:      "disk_usage_bytes",
 			Help:      "Bytes on disk currently used by cache instance.",
 		},
-		[]string{"path"},
+		[]string{"id"},
 	)
 
 	// CachedItems discloses the number of items stored by caches
@@ -42,7 +42,7 @@ var (
 			Name:      "items_total",
 			Help:      "Total number of items currently cached by instance.",
 		},
-		[]string{"path"},
+		[]string{"id"},
 	)
 
 	// CacheHitsDisk discloses the number of hits for items cached on disk
@@ -53,7 +53,7 @@ var (
 			Name:      "disk_hits_total",
 			Help:      "Total number of hits for items cached on disk by an instance.",
 		},
-		[]string{"path"},
+		[]string{"id"},
 	)
 
 	// CacheHitsMemory discloses the number of hits for items cached in memory
@@ -64,7 +64,7 @@ var (
 			Name:      "memory_hits_total",
 			Help:      "Total number of hits for items cached in memory by an instance.",
 		},
-		[]string{"path"},
+		[]string{"id"},
 	)
 )