perf: cache with precomputed etag

repository/gorm/stamp.go

@@ -15,6 +15,7 @@ import (
 	"github.com/traPtitech/traQ/event"
 	"github.com/traPtitech/traQ/model"
 	"github.com/traPtitech/traQ/repository"
+	"github.com/traPtitech/traQ/utils/etag"
 	"github.com/traPtitech/traQ/utils/gormutil"
 	"github.com/traPtitech/traQ/utils/validator"
 )
@@ -25,7 +26,7 @@ type stampRepository struct {
 	db      *gorm.DB
 	hub     *hub.Hub
 	stamps  *sc.Cache[struct{}, map[uuid.UUID]*model.Stamp]
-	perType *sc.Cache[repository.StampType, []*model.StampWithThumbnail]
+	perType *sc.Cache[repository.StampType, *etag.Entity[[]*model.StampWithThumbnail]]
 }
 
 func makeStampRepository(db *gorm.DB, hub *hub.Hub) *stampRepository {
@@ -48,7 +49,7 @@ func (r *stampRepository) loadStamps(_ context.Context, _ struct{}) (map[uuid.UU
 	return stampsMap, nil
 }
 
-func (r *stampRepository) loadFilteredStamps(ctx context.Context, stampType repository.StampType) ([]*model.StampWithThumbnail, error) {
+func (r *stampRepository) loadFilteredStamps(ctx context.Context, stampType repository.StampType) (*etag.Entity[[]*model.StampWithThumbnail], error) {
 	stamps, err := r.stamps.Get(ctx, struct{}{})
 	if err != nil {
 		return nil, err
@@ -106,7 +107,13 @@ func (r *stampRepository) loadFilteredStamps(ctx context.Context, stampType repo
 	}
 
 	sort.Slice(arr, func(i, j int) bool { return arr[i].ID.String() < arr[j].ID.String() })
-	return arr, nil
+
+	stampsWithEtag, err := etag.New(arr)
+	if err != nil {
+		return nil, err
+	}
+
+	return stampsWithEtag, nil
 }
 
 func (r *stampRepository) purgeCache() {
@@ -304,7 +311,7 @@ func (r *stampRepository) DeleteStamp(ctx context.Context, id uuid.UUID) (err er
 }
 
 // GetAllStampsWithThumbnail implements StampRepository interface.
-func (r *stampRepository) GetAllStampsWithThumbnail(ctx context.Context, stampType repository.StampType) (stampsWithThumbnail []*model.StampWithThumbnail, err error) {
+func (r *stampRepository) GetAllStampsWithThumbnail(ctx context.Context, stampType repository.StampType) (*etag.Entity[[]*model.StampWithThumbnail], error) {
 	return r.perType.Get(ctx, stampType)
 }
 

repository/gorm/stamp_test.go

@@ -248,13 +248,13 @@ func TestRepositoryImpl_GetAllStampsWithThumbnail(t *testing.T) {
 
 	t.Run("without thumbnail", func(t *testing.T) {
 		t.Parallel()
-		arr, err := repo.GetAllStampsWithThumbnail(context.TODO(), repository.StampTypeAll)
+		stamps, err := repo.GetAllStampsWithThumbnail(context.TODO(), repository.StampTypeAll)
 		if !assert.NoError(err) {
 			t.FailNow()
 		}
-		assert.Len(arr, n*2)
+		assert.Len(stamps.Value(), n*2)
 		cnt := 0
-		for _, s := range arr {
+		for _, s := range stamps.Value() {
 			if !s.HasThumbnail {
 				cnt++
 			}
@@ -263,13 +263,13 @@ func TestRepositoryImpl_GetAllStampsWithThumbnail(t *testing.T) {
 	})
 	t.Run("with thumbnail", func(t *testing.T) {
 		t.Parallel()
-		arr, err := repo.GetAllStampsWithThumbnail(context.TODO(), repository.StampTypeAll)
+		stamps, err := repo.GetAllStampsWithThumbnail(context.TODO(), repository.StampTypeAll)
 		if !assert.NoError(err) {
 			t.FailNow()
 		}
-		assert.Len(arr, n*2)
+		assert.Len(stamps.Value(), n*2)
 		cnt := 0
-		for _, s := range arr {
+		for _, s := range stamps.Value() {
 			if s.HasThumbnail {
 				cnt++
 			}

repository/stamp.go

@@ -7,6 +7,7 @@ import (
 	"github.com/gofrs/uuid"
 
 	"github.com/traPtitech/traQ/model"
+	"github.com/traPtitech/traQ/utils/etag"
 	"github.com/traPtitech/traQ/utils/optional"
 )
 
@@ -96,7 +97,7 @@ type StampRepository interface {
 	//
 	// 成功した場合、スタンプのIDでソートされた配列とnilを返します。
 	// DBによるエラーを返すことがあります。
-	GetAllStampsWithThumbnail(ctx context.Context, stampType StampType) (stamps []*model.StampWithThumbnail, err error)
+	GetAllStampsWithThumbnail(ctx context.Context, stampType StampType) (stampsWithETag *etag.Entity[[]*model.StampWithThumbnail], err error)
 	// StampExists 指定したIDのスタンプが存在するかどうかを返します
 	//
 	// 存在する場合、trueとnilを返します。

router/extension/precond.go

@@ -12,6 +12,7 @@ import (
 	"github.com/labstack/echo/v4"
 
 	"github.com/traPtitech/traQ/router/consts"
+	"github.com/traPtitech/traQ/utils/etag"
 )
 
 func scanETag(s string) (eTag string, remain string) {
@@ -223,3 +224,23 @@ func ServeWithETag(c echo.Context, contentType string, bytes []byte) error {
 	}
 	return c.Blob(http.StatusOK, contentType, bytes)
 }
+
+// ServeJSONWithPrecomputedETag 事前に計算されたEtagを付与してJSONを返します。リクエストの条件に合うときは304を返します。
+func ServeJSONWithPrecomputedETag[T any](c echo.Context, e *etag.Entity[T]) error {
+	// NOTE: prettyクエリがあるときはEtagを無視して整形されたJSONを返す
+	if _, pretty := c.QueryParams()["pretty"]; pretty {
+		return c.JSONPretty(http.StatusOK, e.Value(), "  ")
+	}
+
+	c.Response().Header().Set(consts.HeaderETag, "\""+e.ETag()+"\"")
+
+	done, err := CheckPreconditions(c, time.Time{})
+	if err != nil {
+		return err
+	}
+	if done {
+		return nil
+	}
+
+	return c.JSON(http.StatusOK, e.Value())
+}

router/v1/public.go

@@ -123,8 +123,8 @@
 			return nil, err
 		}
 
-		stampNames := make([]string, len(stamps))
-		for i, stamp := range stamps {
+		stampNames := make([]string, len(stamps.Value()))
+		for i, stamp := range stamps.Value() {
 			stampNames[i] = stamp.Name
 		}
 
@@ -151,8 +151,8 @@
 		buf.WriteString(".s16{width:16px;height:16px}")
 		buf.WriteString(".s24{width:24px;height:24px}")
 		buf.WriteString(".s32{width:32px;height:32px}")
-		for _, stamp := range stamps {
+		for _, stamp := range stamps.Value() {
 			buf.WriteString(fmt.Sprintf(".emoji.e_%s{background-image:url(/api/1.0/public/emoji/%s)}", stamp.Name, stamp.ID))
 		}
 		return buf.Bytes(), nil
 	}

router/v3/stamps.go

@@ -71,7 +71,7 @@ func (h *Handlers) GetStamps(c echo.Context) error {
 		return herror.InternalServerError(err)
 	}
 
-	return extension.ServeJSONWithETag(c, stamps)
+	return extension.ServeJSONWithPrecomputedETag(c, stamps)
 }
 
 // CreateStamp POST /stamps

utils/etag/etag.go

@@ -0,0 +1,43 @@
+package etag
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+
+	jsonIter "github.com/json-iterator/go"
+)
+
+type Entity[T any] struct {
+	value T
+	etag  string
+}
+
+var jsonIterForETag = jsonIter.Config{
+	EscapeHTML:                    false,
+	MarshalFloatWith6Digits:       true,
+	ObjectFieldMustBeSimpleString: true,
+	// ここより上はjsonIter.ConfigFastestと同様
+	SortMapKeys: true, // 順番が一致しないとEtagが一致しないのでソートを有効にする
+}.Froze()
+
+func New[T any](data T) (*Entity[T], error) {
+	b, err := jsonIterForETag.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+
+	md5Res := md5.Sum(b)
+
+	return &Entity[T]{
+		value: data,
+		etag:  hex.EncodeToString(md5Res[:]),
+	}, nil
+}
+
+func (e Entity[T]) Value() T {
+	return e.value
+}
+
+func (e Entity[T]) ETag() string {
+	return e.etag
+}