Add cache for common package queries (#22491)

This adds a cache for common package queries in `GetPackageDescriptor`.
Code which needs to process a list of packages benefits from this
change. This skips 350 queries in the package integration tests for
example.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/packages/descriptor.go

@@ -11,6 +11,7 @@ import (
 
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/cache"
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/packages/alpine"
 	"code.gitea.io/gitea/modules/packages/arch"
@@ -102,22 +103,26 @@ func (pd *PackageDescriptor) CalculateBlobSize() int64 {
 
 // GetPackageDescriptor gets the package description for a version
 func GetPackageDescriptor(ctx context.Context, pv *PackageVersion) (*PackageDescriptor, error) {
-	p, err := GetPackageByID(ctx, pv.PackageID)
+	return getPackageDescriptor(ctx, pv, cache.NewEphemeralCache())
+}
+
+func getPackageDescriptor(ctx context.Context, pv *PackageVersion, c *cache.EphemeralCache) (*PackageDescriptor, error) {
+	p, err := cache.GetWithEphemeralCache(ctx, c, "package", pv.PackageID, GetPackageByID)
 	if err != nil {
 		return nil, err
 	}
-	o, err := user_model.GetUserByID(ctx, p.OwnerID)
+	o, err := cache.GetWithEphemeralCache(ctx, c, "user", p.OwnerID, user_model.GetUserByID)
 	if err != nil {
 		return nil, err
 	}
 	var repository *repo_model.Repository
 	if p.RepoID > 0 {
-		repository, err = repo_model.GetRepositoryByID(ctx, p.RepoID)
+		repository, err = cache.GetWithEphemeralCache(ctx, c, "repo", p.RepoID, repo_model.GetRepositoryByID)
 		if err != nil && !repo_model.IsErrRepoNotExist(err) {
 			return nil, err
 		}
 	}
-	creator, err := user_model.GetUserByID(ctx, pv.CreatorID)
+	creator, err := cache.GetWithEphemeralCache(ctx, c, "user", pv.CreatorID, user_model.GetUserByID)
 	if err != nil {
 		if errors.Is(err, util.ErrNotExist) {
 			creator = user_model.NewGhostUser()
@@ -145,9 +150,13 @@ func GetPackageDescriptor(ctx context.Context, pv *PackageVersion) (*PackageDesc
 		return nil, err
 	}
 
-	pfds, err := GetPackageFileDescriptors(ctx, pfs)
-	if err != nil {
-		return nil, err
+	pfds := make([]*PackageFileDescriptor, 0, len(pfs))
+	for _, pf := range pfs {
+		pfd, err := getPackageFileDescriptor(ctx, pf, c)
+		if err != nil {
+			return nil, err
+		}
+		pfds = append(pfds, pfd)
 	}
 
 	var metadata any
@@ -221,7 +230,11 @@ func GetPackageDescriptor(ctx context.Context, pv *PackageVersion) (*PackageDesc
 
 // GetPackageFileDescriptor gets a package file descriptor for a package file
 func GetPackageFileDescriptor(ctx context.Context, pf *PackageFile) (*PackageFileDescriptor, error) {
-	pb, err := GetBlobByID(ctx, pf.BlobID)
+	return getPackageFileDescriptor(ctx, pf, cache.NewEphemeralCache())
+}
+
+func getPackageFileDescriptor(ctx context.Context, pf *PackageFile, c *cache.EphemeralCache) (*PackageFileDescriptor, error) {
+	pb, err := cache.GetWithEphemeralCache(ctx, c, "package_file_blob", pf.BlobID, GetBlobByID)
 	if err != nil {
 		return nil, err
 	}
@@ -251,9 +264,13 @@ func GetPackageFileDescriptors(ctx context.Context, pfs []*PackageFile) ([]*Pack
 
 // GetPackageDescriptors gets the package descriptions for the versions
 func GetPackageDescriptors(ctx context.Context, pvs []*PackageVersion) ([]*PackageDescriptor, error) {
+	return getPackageDescriptors(ctx, pvs, cache.NewEphemeralCache())
+}
+
+func getPackageDescriptors(ctx context.Context, pvs []*PackageVersion, c *cache.EphemeralCache) ([]*PackageDescriptor, error) {
 	pds := make([]*PackageDescriptor, 0, len(pvs))
 	for _, pv := range pvs {
-		pd, err := GetPackageDescriptor(ctx, pv)
+		pd, err := getPackageDescriptor(ctx, pv, c)
 		if err != nil {
 			return nil, err
 		}

modules/cache/context.go

@@ -5,176 +5,39 @@ package cache
 
 import (
 	"context"
-	"sync"
 	"time"
-
-	"code.gitea.io/gitea/modules/log"
 )
 
-// cacheContext is a context that can be used to cache data in a request level context
-// This is useful for caching data that is expensive to calculate and is likely to be
-// used multiple times in a request.
-type cacheContext struct {
-	data    map[any]map[any]any
-	lock    sync.RWMutex
-	created time.Time
-	discard bool
-}
-
-func (cc *cacheContext) Get(tp, key any) any {
-	cc.lock.RLock()
-	defer cc.lock.RUnlock()
-	return cc.data[tp][key]
-}
-
-func (cc *cacheContext) Put(tp, key, value any) {
-	cc.lock.Lock()
-	defer cc.lock.Unlock()
-
-	if cc.discard {
-		return
-	}
-
-	d := cc.data[tp]
-	if d == nil {
-		d = make(map[any]any)
-		cc.data[tp] = d
-	}
-	d[key] = value
-}
-
-func (cc *cacheContext) Delete(tp, key any) {
-	cc.lock.Lock()
-	defer cc.lock.Unlock()
-	delete(cc.data[tp], key)
-}
+type cacheContextKeyType struct{}
 
-func (cc *cacheContext) Discard() {
-	cc.lock.Lock()
-	defer cc.lock.Unlock()
-	cc.data = nil
-	cc.discard = true
-}
+var cacheContextKey = cacheContextKeyType{}
 
-func (cc *cacheContext) isDiscard() bool {
-	cc.lock.RLock()
-	defer cc.lock.RUnlock()
-	return cc.discard
-}
-
-// cacheContextLifetime is the max lifetime of cacheContext.
-// Since cacheContext is used to cache data in a request level context, 5 minutes is enough.
-// If a cacheContext is used more than 5 minutes, it's probably misuse.
-const cacheContextLifetime = 5 * time.Minute
-
-var timeNow = time.Now
-
-func (cc *cacheContext) Expired() bool {
-	return timeNow().Sub(cc.created) > cacheContextLifetime
-}
-
-var cacheContextKey = struct{}{}
-
-/*
-Since there are both WithCacheContext and WithNoCacheContext,
-it may be confusing when there is nesting.
-
-Some cases to explain the design:
-
-When:
-- A, B or C means a cache context.
-- A', B' or C' means a discard cache context.
-- ctx means context.Backgrand().
-- A(ctx) means a cache context with ctx as the parent context.
-- B(A(ctx)) means a cache context with A(ctx) as the parent context.
-- With is alias of WithCacheContext.
-- WithNo is alias of WithNoCacheContext.
-
-So:
-- With(ctx) -> A(ctx)
-- With(With(ctx)) -> A(ctx), not B(A(ctx)), always reuse parent cache context if possible.
-- With(With(With(ctx))) -> A(ctx), not C(B(A(ctx))), ditto.
-- WithNo(ctx) -> ctx, not A'(ctx), don't create new cache context if we don't have to.
-- WithNo(With(ctx)) -> A'(ctx)
-- WithNo(WithNo(With(ctx))) -> A'(ctx), not B'(A'(ctx)), don't create new cache context if we don't have to.
-- With(WithNo(With(ctx))) -> B(A'(ctx)), not A(ctx), never reuse a discard cache context.
-- WithNo(With(WithNo(With(ctx)))) -> B'(A'(ctx))
-- With(WithNo(With(WithNo(With(ctx))))) -> C(B'(A'(ctx))), so there's always only one not-discard cache context.
-*/
+// contextCacheLifetime is the max lifetime of context cache.
+// Since context cache is used to cache data in a request level context, 5 minutes is enough.
+// If a context cache is used more than 5 minutes, it's probably abused.
+const contextCacheLifetime = 5 * time.Minute
 
 func WithCacheContext(ctx context.Context) context.Context {
-	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
-		if !c.isDiscard() {
-			// reuse parent context
-			return ctx
-		}
-	}
-	// FIXME: review the use of this nolint directive
-	return context.WithValue(ctx, cacheContextKey, &cacheContext{ //nolint:staticcheck
-		data:    make(map[any]map[any]any),
-		created: timeNow(),
-	})
-}
-
-func WithNoCacheContext(ctx context.Context) context.Context {
-	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
-		// The caller want to run long-life tasks, but the parent context is a cache context.
-		// So we should disable and clean the cache data, or it will be kept in memory for a long time.
-		c.Discard()
+	if c := GetContextCache(ctx); c != nil {
 		return ctx
 	}
-
-	return ctx
+	return context.WithValue(ctx, cacheContextKey, NewEphemeralCache(contextCacheLifetime))
 }
 
-func GetContextData(ctx context.Context, tp, key any) any {
-	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
-		if c.Expired() {
-			// The warning means that the cache context is misused for long-life task,
-			// it can be resolved with WithNoCacheContext(ctx).
-			log.Warn("cache context is expired, is highly likely to be misused for long-life tasks: %v", c)
-			return nil
-		}
-		return c.Get(tp, key)
-	}
-	return nil
-}
-
-func SetContextData(ctx context.Context, tp, key, value any) {
-	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
-		if c.Expired() {
-			// The warning means that the cache context is misused for long-life task,
-			// it can be resolved with WithNoCacheContext(ctx).
-			log.Warn("cache context is expired, is highly likely to be misused for long-life tasks: %v", c)
-			return
-		}
-		c.Put(tp, key, value)
-		return
-	}
-}
-
-func RemoveContextData(ctx context.Context, tp, key any) {
-	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
-		if c.Expired() {
-			// The warning means that the cache context is misused for long-life task,
-			// it can be resolved with WithNoCacheContext(ctx).
-			log.Warn("cache context is expired, is highly likely to be misused for long-life tasks: %v", c)
-			return
-		}
-		c.Delete(tp, key)
-	}
+func GetContextCache(ctx context.Context) *EphemeralCache {
+	c, _ := ctx.Value(cacheContextKey).(*EphemeralCache)
+	return c
 }
 
 // GetWithContextCache returns the cache value of the given key in the given context.
+// FIXME: in some cases, the "context cache" should not be used, because it has uncontrollable behaviors
+// For example, these calls:
+// * GetWithContextCache(TargetID) -> OtherCodeCreateModel(TargetID) -> GetWithContextCache(TargetID)
+// Will cause the second call is not able to get the correct created target.
+// UNLESS it is certain that the target won't be changed during the request, DO NOT use it.
 func GetWithContextCache[T, K any](ctx context.Context, groupKey string, targetKey K, f func(context.Context, K) (T, error)) (T, error) {
-	v := GetContextData(ctx, groupKey, targetKey)
-	if vv, ok := v.(T); ok {
-		return vv, nil
-	}
-	t, err := f(ctx, targetKey)
-	if err != nil {
-		return t, err
+	if c := GetContextCache(ctx); c != nil {
+		return GetWithEphemeralCache(ctx, c, groupKey, targetKey, f)
 	}
-	SetContextData(ctx, groupKey, targetKey, t)
-	return t, nil
+	return f(ctx, targetKey)
 }

modules/cache/context_test.go

@@ -8,27 +8,29 @@ import (
 	"testing"
 	"time"
 
+	"code.gitea.io/gitea/modules/test"
+
 	"github.com/stretchr/testify/assert"
 )
 
 func TestWithCacheContext(t *testing.T) {
 	ctx := WithCacheContext(t.Context())
-
-	v := GetContextData(ctx, "empty_field", "my_config1")
+	c := GetContextCache(ctx)
+	v, _ := c.Get("empty_field", "my_config1")
 	assert.Nil(t, v)
 
 	const field = "system_setting"
-	v = GetContextData(ctx, field, "my_config1")
+	v, _ = c.Get(field, "my_config1")
 	assert.Nil(t, v)
-	SetContextData(ctx, field, "my_config1", 1)
-	v = GetContextData(ctx, field, "my_config1")
+	c.Put(field, "my_config1", 1)
+	v, _ = c.Get(field, "my_config1")
 	assert.NotNil(t, v)
 	assert.Equal(t, 1, v.(int))
 
-	RemoveContextData(ctx, field, "my_config1")
-	RemoveContextData(ctx, field, "my_config2") // remove a non-exist key
+	c.Delete(field, "my_config1")
+	c.Delete(field, "my_config2") // remove a non-exist key
 
-	v = GetContextData(ctx, field, "my_config1")
+	v, _ = c.Get(field, "my_config1")
 	assert.Nil(t, v)
 
 	vInt, err := GetWithContextCache(ctx, field, "my_config1", func(context.Context, string) (int, error) {
@@ -37,42 +39,12 @@ func TestWithCacheContext(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, 1, vInt)
 
-	v = GetContextData(ctx, field, "my_config1")
+	v, _ = c.Get(field, "my_config1")
 	assert.EqualValues(t, 1, v)
 
-	now := timeNow
-	defer func() {
-		timeNow = now
-	}()
-	timeNow = func() time.Time {
-		return now().Add(5 * time.Minute)
-	}
-	v = GetContextData(ctx, field, "my_config1")
-	assert.Nil(t, v)
-}
-
-func TestWithNoCacheContext(t *testing.T) {
-	ctx := t.Context()
-
-	const field = "system_setting"
-
-	v := GetContextData(ctx, field, "my_config1")
-	assert.Nil(t, v)
-	SetContextData(ctx, field, "my_config1", 1)
-	v = GetContextData(ctx, field, "my_config1")
-	assert.Nil(t, v) // still no cache
-
-	ctx = WithCacheContext(ctx)
-	v = GetContextData(ctx, field, "my_config1")
-	assert.Nil(t, v)
-	SetContextData(ctx, field, "my_config1", 1)
-	v = GetContextData(ctx, field, "my_config1")
-	assert.NotNil(t, v)
-
-	ctx = WithNoCacheContext(ctx)
-	v = GetContextData(ctx, field, "my_config1")
+	defer test.MockVariableValue(&timeNow, func() time.Time {
+		return time.Now().Add(5 * time.Minute)
+	})()
+	v, _ = c.Get(field, "my_config1")
 	assert.Nil(t, v)
-	SetContextData(ctx, field, "my_config1", 1)
-	v = GetContextData(ctx, field, "my_config1")
-	assert.Nil(t, v) // still no cache
 }

modules/cache/ephemeral.go

@@ -0,0 +1,90 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// EphemeralCache is a cache that can be used to store data in a request level context
+// This is useful for caching data that is expensive to calculate and is likely to be
+// used multiple times in a request.
+type EphemeralCache struct {
+	data          map[any]map[any]any
+	lock          sync.RWMutex
+	created       time.Time
+	checkLifeTime time.Duration
+}
+
+var timeNow = time.Now
+
+func NewEphemeralCache(checkLifeTime ...time.Duration) *EphemeralCache {
+	return &EphemeralCache{
+		data:          make(map[any]map[any]any),
+		created:       timeNow(),
+		checkLifeTime: util.OptionalArg(checkLifeTime, 0),
+	}
+}
+
+func (cc *EphemeralCache) checkExceededLifeTime(tp, key any) bool {
+	if cc.checkLifeTime > 0 && timeNow().Sub(cc.created) > cc.checkLifeTime {
+		log.Warn("EphemeralCache is expired, is highly likely to be abused for long-life tasks: %v, %v", tp, key)
+		return true
+	}
+	return false
+}
+
+func (cc *EphemeralCache) Get(tp, key any) (any, bool) {
+	if cc.checkExceededLifeTime(tp, key) {
+		return nil, false
+	}
+	cc.lock.RLock()
+	defer cc.lock.RUnlock()
+	ret, ok := cc.data[tp][key]
+	return ret, ok
+}
+
+func (cc *EphemeralCache) Put(tp, key, value any) {
+	if cc.checkExceededLifeTime(tp, key) {
+		return
+	}
+
+	cc.lock.Lock()
+	defer cc.lock.Unlock()
+
+	d := cc.data[tp]
+	if d == nil {
+		d = make(map[any]any)
+		cc.data[tp] = d
+	}
+	d[key] = value
+}
+
+func (cc *EphemeralCache) Delete(tp, key any) {
+	if cc.checkExceededLifeTime(tp, key) {
+		return
+	}
+
+	cc.lock.Lock()
+	defer cc.lock.Unlock()
+	delete(cc.data[tp], key)
+}
+
+func GetWithEphemeralCache[T, K any](ctx context.Context, c *EphemeralCache, groupKey string, targetKey K, f func(context.Context, K) (T, error)) (T, error) {
+	v, has := c.Get(groupKey, targetKey)
+	if vv, ok := v.(T); has && ok {
+		return vv, nil
+	}
+	t, err := f(ctx, targetKey)
+	if err != nil {
+		return t, err
+	}
+	c.Put(groupKey, targetKey, t)
+	return t, nil
+}