feat: implement lfu based cache strategy

pkg/storage/driver/cache/lfu/testsuite/main.go

@@ -0,0 +1,41 @@
+package testsuite
+
+import (
+	"reflect"
+	"runtime"
+	"strings"
+	"testing"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+type StoreFactory func(testName string) lfu.Store[string, string]
+type testCase func(t *testing.T, store lfu.Store[string, string]) error
+
+var testCases = []testCase{
+	testSetGetDelete,
+	testEviction,
+	testConcurrent,
+	testMultipleSet,
+	testTTL,
+}
+
+func TestCacheWithStore(t *testing.T, factory StoreFactory) {
+	for _, tc := range testCases {
+		funcName := runtime.FuncForPC(reflect.ValueOf(tc).Pointer()).Name()
+		funcNameParts := strings.Split(funcName, "/")
+		testName := funcNameParts[len(funcNameParts)-1]
+		func(tc testCase) {
+			t.Run(testName, func(t *testing.T) {
+				t.Parallel()
+
+				store := factory(testName)
+
+				if err := tc(t, store); err != nil {
+					t.Fatalf("%+v", errors.WithStack(err))
+				}
+			})
+		}(tc)
+	}
+}

pkg/storage/driver/cache/lfu/testsuite/test_concurrent.go

@@ -0,0 +1,67 @@
+package testsuite
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+func testConcurrent(t *testing.T, store lfu.Store[string, string]) error {
+	const value = "foobar"
+	totalKeys := 25
+	totalSize := len(value) * totalKeys
+	capacity := totalSize / 2
+
+	cache := lfu.NewCache[string, string](store,
+		lfu.WithCapacity[string, string](capacity),
+		lfu.WithLog[string, string](t.Logf),
+	)
+
+	var wg sync.WaitGroup
+
+	wg.Add(totalKeys)
+
+	loops := totalKeys * 10
+
+	for i := 0; i < totalKeys; i++ {
+		key := fmt.Sprintf("key%d", i)
+		func(key string) {
+			go func() {
+				defer wg.Done()
+				for i := 0; i < loops; i++ {
+					if err := cache.Set(key, value); err != nil {
+						t.Errorf("%+v", errors.WithStack(err))
+					}
+				}
+			}()
+		}(key)
+	}
+
+	wg.Wait()
+
+	t.Logf("cache before final evict [capacity: %d, size: %d, len: %d]", cache.Capacity(), cache.Size(), cache.Len())
+
+	if err := cache.Evict(); err != nil {
+		t.Errorf("%+v", errors.WithStack(err))
+	}
+
+	t.Logf("cache after final evict [capacity: %d, size: %d, len: %d]", cache.Capacity(), cache.Size(), cache.Len())
+
+	expectedLength := capacity / len(value)
+	if e, g := expectedLength, cache.Len(); e < g {
+		t.Errorf("cache.Len(): expected <= %d, got %d", e, g)
+	}
+
+	if cache.Size() > capacity {
+		t.Errorf("cache.Size(): expected <= %d, got %d", capacity, cache.Size())
+	}
+
+	if e, g := expectedLength*len(value), cache.Size(); e < g {
+		t.Errorf("cache.Size(): expected <= %d, got %d", e, g)
+	}
+
+	return nil
+}

pkg/storage/driver/cache/lfu/testsuite/test_eviction.go

@@ -0,0 +1,70 @@
+package testsuite
+
+import (
+	"testing"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+func testEviction(t *testing.T, store lfu.Store[string, string]) error {
+	cache := lfu.NewCache[string, string](store,
+		lfu.WithCapacity[string, string](10),
+		lfu.WithLog[string, string](t.Logf),
+	)
+
+	if err := cache.Set("key1", "key1"); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if err := cache.Set("key2", "key2"); err != nil {
+		return errors.WithStack(err)
+	}
+
+	// Increment frequency of key2
+	if _, err := cache.Get("key2"); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := 8, cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Set("key3", "key3"); err != nil {
+		return errors.WithStack(err)
+	}
+
+	t.Logf("cache [capacity: %d, size: %d, len: %d]", cache.Capacity(), cache.Size(), cache.Len())
+
+	_, err := cache.Get("key1")
+	if err == nil {
+		t.Errorf("expected 'key1' to be evicted")
+	}
+
+	if !errors.Is(err, lfu.ErrNotFound) {
+		t.Errorf("expected err to be 'ErrNotFound'")
+	}
+
+	value, err := cache.Get("key2")
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := "key2", value; e < g {
+		t.Errorf("cache.Get(\"key2\"): expected %v, got %v", e, g)
+	}
+
+	if e, g := cache.Capacity(), cache.Size(); e < g {
+		t.Errorf("cache.Size(): expected <= %d, got %d", e, g)
+	}
+
+	if e, g := 2, cache.Len(); e != g {
+		t.Errorf("cache.Len(): expected %d, got %d", e, g)
+	}
+
+	if cache.Size() < 0 {
+		t.Errorf("cache.Size(): expected value >= 0, got %d", cache.Size())
+	}
+
+	return nil
+}

pkg/storage/driver/cache/lfu/testsuite/test_multiple_set.go

@@ -0,0 +1,80 @@
+package testsuite
+
+import (
+	"testing"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+func testMultipleSet(t *testing.T, store lfu.Store[string, string]) error {
+	const (
+		key         = "mykey"
+		firstValue  = "foo"
+		secondValue = "bar"
+		thirdValue  = "foobar"
+	)
+
+	cache := lfu.NewCache[string, string](store)
+
+	if e, g := 0, cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Set(key, firstValue); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := len(firstValue), cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	retrieved, err := cache.Get(key)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := firstValue, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Set(key, secondValue); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := len(secondValue), cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	retrieved, err = cache.Get(key)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := secondValue, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Set(key, thirdValue); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := len(thirdValue), cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	retrieved, err = cache.Get(key)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := thirdValue, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	if e, g := len(thirdValue), cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	return nil
+}

pkg/storage/driver/cache/lfu/testsuite/test_set_get_delete.go

@@ -0,0 +1,66 @@
+package testsuite
+
+import (
+	"testing"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+func testSetGetDelete(t *testing.T, store lfu.Store[string, string]) error {
+	const (
+		key   = "mykey"
+		value = "foobar"
+	)
+
+	cache := lfu.NewCache[string, string](store, lfu.WithCapacity[string, string](10))
+
+	if e, g := 0, cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Set(key, value); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := len(value), cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if e, g := 1, cache.Len(); e != g {
+		t.Errorf("cache.Len(): expected '%v', got '%v'", e, g)
+	}
+
+	retrieved, err := cache.Get(key)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := value, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	if err := cache.Delete(key); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if _, err := cache.Get(key); err == nil || !errors.Is(err, lfu.ErrNotFound) {
+		t.Errorf("cache.Get(key): err should be lfu.ErrNotFound, got '%v'", errors.WithStack(err))
+	}
+
+	if e, g := value, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	if e, g := 0, cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if e, g := 0, cache.Len(); e != g {
+		t.Errorf("cache.Len(): expected '%v', got '%v'", e, g)
+	}
+
+	t.Logf("cache [capacity: %d, size: %d, len: %d]", cache.Capacity(), cache.Size(), cache.Len())
+
+	return nil
+}

pkg/storage/driver/cache/lfu/testsuite/test_ttl.go

@@ -0,0 +1,54 @@
+package testsuite
+
+import (
+	"testing"
+	"time"
+
+	"forge.cadoles.com/arcad/edge/pkg/storage/driver/cache/lfu"
+	"github.com/pkg/errors"
+)
+
+func testTTL(t *testing.T, store lfu.Store[string, string]) error {
+	const (
+		key   = "mykey"
+		value = "foobar"
+	)
+
+	ttl := time.Second
+
+	cache := lfu.NewCache[string, string](store,
+		lfu.WithTTL[string, string](ttl),
+		lfu.WithCapacity[string, string](10),
+	)
+
+	if err := cache.Set(key, value); err != nil {
+		return errors.WithStack(err)
+	}
+
+	retrieved, err := cache.Get(key)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	if e, g := value, retrieved; e != g {
+		t.Errorf("cache.Get(key): expected '%v', got '%v'", e, g)
+	}
+
+	time.Sleep(ttl * 2)
+
+	if _, err := cache.Get(key); !errors.Is(err, lfu.ErrNotFound) {
+		t.Errorf("cache.Get(key): expected err == lfu.ErrNotFound, got '%v'", err)
+	}
+
+	t.Logf("cache [capacity: %d, size: %d, len: %d]", cache.Capacity(), cache.Size(), cache.Len())
+
+	if e, g := 0, cache.Size(); e != g {
+		t.Errorf("cache.Size(): expected '%v', got '%v'", e, g)
+	}
+
+	if e, g := 0, cache.Len(); e != g {
+		t.Errorf("cache.Len(): expected '%v', got '%v'", e, g)
+	}
+
+	return nil
+}