From 7f6852bbd2f440b5c49b616966e96bfd5ff30c65 Mon Sep 17 00:00:00 2001
From: Alexander Chuprov <a.chuprov@yadro.com>
Date: Thu, 30 Nov 2023 11:45:31 +0300
Subject: [PATCH] [#639] node: Refactor TTL cache

Migrate from internal to external TTL implementation

Signed-off-by: Alexander Chuprov <a.chuprov@yadro.com>
---
 cmd/frostfs-node/cache.go      | 29 ++++++------------
 cmd/frostfs-node/cache_test.go | 56 ++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 20 deletions(-)
 create mode 100644 cmd/frostfs-node/cache_test.go

diff --git a/cmd/frostfs-node/cache.go b/cmd/frostfs-node/cache.go
index cd383a5c..bf68d245 100644
--- a/cmd/frostfs-node/cache.go
+++ b/cmd/frostfs-node/cache.go
@@ -12,38 +12,29 @@ import (
 	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
 	netmapSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
 	lru "github.com/hashicorp/golang-lru/v2"
+	"github.com/hashicorp/golang-lru/v2/expirable"
 )
 
 type netValueReader[K any, V any] func(K) (V, error)
 
-type valueWithTime[V any] struct {
+type valueWithError[V any] struct {
 	v V
-	t time.Time
 	// cached error in order to not repeat failed request for some time
 	e error
 }
 
 // entity that provides TTL cache interface.
 type ttlNetCache[K comparable, V any] struct {
-	ttl time.Duration
-
-	sz int
-
-	cache *lru.Cache[K, *valueWithTime[V]]
-
-	netRdr netValueReader[K, V]
-
+	cache     *expirable.LRU[K, *valueWithError[V]]
+	netRdr    netValueReader[K, V]
 	keyLocker *utilSync.KeyLocker[K]
 }
 
 // complicates netValueReader with TTL caching mechanism.
 func newNetworkTTLCache[K comparable, V any](sz int, ttl time.Duration, netRdr netValueReader[K, V]) *ttlNetCache[K, V] {
-	cache, err := lru.New[K, *valueWithTime[V]](sz)
-	fatalOnErr(err)
+	cache := expirable.NewLRU[K, *valueWithError[V]](sz, nil, ttl)
 
 	return &ttlNetCache[K, V]{
-		ttl:       ttl,
-		sz:        sz,
 		cache:     cache,
 		netRdr:    netRdr,
 		keyLocker: utilSync.NewKeyLocker[K](),
@@ -57,7 +48,7 @@ func newNetworkTTLCache[K comparable, V any](sz int, ttl time.Duration, netRdr n
 // returned value should not be modified.
 func (c *ttlNetCache[K, V]) get(key K) (V, error) {
 	val, ok := c.cache.Peek(key)
-	if ok && time.Since(val.t) < c.ttl {
+	if ok {
 		return val.v, val.e
 	}
 
@@ -65,15 +56,14 @@ func (c *ttlNetCache[K, V]) get(key K) (V, error) {
 	defer c.keyLocker.Unlock(key)
 
 	val, ok = c.cache.Peek(key)
-	if ok && time.Since(val.t) < c.ttl {
+	if ok {
 		return val.v, val.e
 	}
 
 	v, err := c.netRdr(key)
 
-	c.cache.Add(key, &valueWithTime[V]{
+	c.cache.Add(key, &valueWithError[V]{
 		v: v,
-		t: time.Now(),
 		e: err,
 	})
 
@@ -84,9 +74,8 @@ func (c *ttlNetCache[K, V]) set(k K, v V, e error) {
 	c.keyLocker.Lock(k)
 	defer c.keyLocker.Unlock(k)
 
-	c.cache.Add(k, &valueWithTime[V]{
+	c.cache.Add(k, &valueWithError[V]{
 		v: v,
-		t: time.Now(),
 		e: e,
 	})
 }
diff --git a/cmd/frostfs-node/cache_test.go b/cmd/frostfs-node/cache_test.go
new file mode 100644
index 00000000..6e076abf
--- /dev/null
+++ b/cmd/frostfs-node/cache_test.go
@@ -0,0 +1,56 @@
+package main
+
+import (
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTTLNetCache(t *testing.T) {
+	ttlDuration := time.Millisecond * 50
+	cache := newNetworkTTLCache[string, time.Time](10, ttlDuration, testNetValueReader)
+
+	key := "key"
+
+	t.Run("Test Add and Get", func(t *testing.T) {
+		ti := time.Now()
+		cache.set(key, ti, nil)
+		val, err := cache.get(key)
+		require.NoError(t, err)
+		require.Equal(t, ti, val)
+	})
+
+	t.Run("Test TTL", func(t *testing.T) {
+		ti := time.Now()
+		cache.set(key, ti, nil)
+		time.Sleep(2 * ttlDuration)
+		val, err := cache.get(key)
+		require.NoError(t, err)
+		require.NotEqual(t, val, ti)
+	})
+
+	t.Run("Test Remove", func(t *testing.T) {
+		ti := time.Now()
+		cache.set(key, ti, nil)
+		cache.remove(key)
+		val, err := cache.get(key)
+		require.NoError(t, err)
+		require.NotEqual(t, val, ti)
+	})
+
+	t.Run("Test Cache Error", func(t *testing.T) {
+		cache.set("error", time.Now(), errors.New("mock error"))
+		_, err := cache.get("error")
+		require.Error(t, err)
+		require.Equal(t, "mock error", err.Error())
+	})
+}
+
+func testNetValueReader(key string) (time.Time, error) {
+	if key == "error" {
+		return time.Now(), errors.New("mock error")
+	}
+	return time.Now(), nil
+}