[#165] Add list session cache

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/cache/listsession.go

@@ -0,0 +1,99 @@
+package cache
+
+import (
+	"fmt"
+	"time"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/data"
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/internal/logs"
+	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
+	"github.com/bluele/gcache"
+	"go.uber.org/zap"
+)
+
+type (
+	// ListSessionCache contains cache for list session (during pagination).
+	ListSessionCache struct {
+		cache  gcache.Cache
+		logger *zap.Logger
+	}
+
+	// ListSessionKey is a key to find a ListSessionCache's entry.
+	ListSessionKey struct {
+		cid    cid.ID
+		prefix string
+		token  string
+	}
+)
+
+const (
+	// DefaultListSessionCacheLifetime is a default lifetime of entries in cache of ListObjects.
+	DefaultListSessionCacheLifetime = time.Second * 60
+	// DefaultListSessionCacheSize is a default size of cache of ListObjects.
+	DefaultListSessionCacheSize = 100
+)
+
+// DefaultListSessionConfig returns new default cache expiration values.
+func DefaultListSessionConfig(logger *zap.Logger) *Config {
+	return &Config{
+		Size:     DefaultListSessionCacheSize,
+		Lifetime: DefaultListSessionCacheLifetime,
+		Logger:   logger,
+	}
+}
+
+func (k *ListSessionKey) String() string {
+	return k.cid.EncodeToString() + k.prefix + k.token
+}
+
+// NewListSessionCache is a constructor which creates an object of ListObjectsCache with the given lifetime of entries.
+func NewListSessionCache(config *Config) *ListSessionCache {
+	gc := gcache.New(config.Size).LRU().Expiration(config.Lifetime).EvictedFunc(func(key interface{}, val interface{}) {
+		session, ok := val.(*data.ListSession)
+		if !ok {
+			config.Logger.Warn(logs.InvalidCacheEntryType, zap.String("actual", fmt.Sprintf("%T", val)),
+				zap.String("expected", fmt.Sprintf("%T", session)))
+		}
+
+		session.Cancel()
+	}).Build()
+	return &ListSessionCache{cache: gc, logger: config.Logger}
+}
+
+// GetListSession returns a list of ObjectInfo.
+func (l *ListSessionCache) GetListSession(key ListSessionKey) *data.ListSession {
+	entry, err := l.cache.Get(key)
+	if err != nil {
+		return nil
+	}
+
+	result, ok := entry.(*data.ListSession)
+	if !ok {
+		l.logger.Warn(logs.InvalidCacheEntryType, zap.String("actual", fmt.Sprintf("%T", entry)),
+			zap.String("expected", fmt.Sprintf("%T", result)))
+		return nil
+	}
+
+	return result
+}
+
+// PutListSession puts a list of object versions to cache.
+func (l *ListSessionCache) PutListSession(key ListSessionKey, session *data.ListSession) error {
+	return l.cache.Set(key, session)
+}
+
+// DeleteListSession removes key from cache.
+func (l *ListSessionCache) DeleteListSession(key ListSessionKey) {
+	l.cache.Remove(key)
+}
+
+// CreateListSessionCacheKey returns ListSessionKey with the given CID, prefix and token.
+func CreateListSessionCacheKey(cnr cid.ID, prefix, token string) ListSessionKey {
+	p := ListSessionKey{
+		cid:    cnr,
+		prefix: prefix,
+		token:  token,
+	}
+
+	return p
+}