Add commit count caching (#2774)

* Add commit count caching

* Small refactoring

* Add different key prefix for refs and commits

* Add configuratuion option to allow to change caching time or disable it

3 files changed, 113 insertions, 12 deletions

diff --git a/modules/cache/cache.go b/modules/cache/cache.go
new file mode 100644
index 0000000000..0a73ae8ae9
--- /dev/null
+++ b/modules/cache/cache.go
@@ -0,0 +1,72 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package cache
+
+import (
+	"code.gitea.io/gitea/modules/setting"
+
+	mc "github.com/go-macaron/cache"
+)
+
+var conn mc.Cache
+
+// NewContext start cache service
+func NewContext() error {
+	if setting.CacheService == nil || conn != nil {
+		return nil
+	}
+
+	var err error
+	conn, err = mc.NewCacher(setting.CacheService.Adapter, mc.Options{
+		Adapter:       setting.CacheService.Adapter,
+		AdapterConfig: setting.CacheService.Conn,
+		Interval:      setting.CacheService.Interval,
+	})
+	return err
+}
+
+// GetInt returns key value from cache with callback when no key exists in cache
+func GetInt(key string, getFunc func() (int, error)) (int, error) {
+	if conn == nil || setting.CacheService.TTL == 0 {
+		return getFunc()
+	}
+	if !conn.IsExist(key) {
+		var (
+			value int
+			err   error
+		)
+		if value, err = getFunc(); err != nil {
+			return value, err
+		}
+		conn.Put(key, value, int64(setting.CacheService.TTL.Seconds()))
+	}
+	return conn.Get(key).(int), nil
+}
+
+// GetInt64 returns key value from cache with callback when no key exists in cache
+func GetInt64(key string, getFunc func() (int64, error)) (int64, error) {
+	if conn == nil || setting.CacheService.TTL == 0 {
+		return getFunc()
+	}
+	if !conn.IsExist(key) {
+		var (
+			value int64
+			err   error
+		)
+		if value, err = getFunc(); err != nil {
+			return value, err
+		}
+		conn.Put(key, value, int64(setting.CacheService.TTL.Seconds()))
+	}
+	return conn.Get(key).(int64), nil
+}
+
+// Remove key from cache
+func Remove(key string) {
+	if conn == nil {
+		return
+	}
+	conn.Delete(key)
+}
diff --git a/modules/context/repo.go b/modules/context/repo.go
index c33396c0f9..3aaf1ce64a 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -13,7 +13,9 @@ import (
 
 	"code.gitea.io/git"
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/cache"
 	"code.gitea.io/gitea/modules/setting"
+
 	"github.com/Unknwon/com"
 	"gopkg.in/editorconfig/editorconfig-core-go.v1"
 	"gopkg.in/macaron.v1"
@@ -100,6 +102,21 @@ func (r *Repository) CanUseTimetracker(issue *models.Issue, user *models.User) b
 		r.IsWriter() || issue.IsPoster(user.ID) || issue.AssigneeID == user.ID)
 }
 
+// GetCommitsCount returns cached commit count for current view
+func (r *Repository) GetCommitsCount() (int64, error) {
+	var contextName string
+	if r.IsViewBranch {
+		contextName = r.BranchName
+	} else if r.IsViewTag {
+		contextName = r.TagName
+	} else {
+		contextName = r.CommitID
+	}
+	return cache.GetInt64(r.Repository.GetCommitsCountCacheKey(contextName, r.IsViewBranch || r.IsViewTag), func() (int64, error) {
+		return r.Commit.CommitsCount()
+	})
+}
+
 // GetEditorconfig returns the .editorconfig definition if found in the
 // HEAD of the default repo branch.
 func (r *Repository) GetEditorconfig() (*editorconfig.Editorconfig, error) {
@@ -535,9 +552,9 @@ func RepoRef() macaron.Handler {
 		ctx.Data["IsViewCommit"] = ctx.Repo.IsViewCommit
 		ctx.Data["CanCreateBranch"] = ctx.Repo.CanCreateBranch()
 
-		ctx.Repo.CommitsCount, err = ctx.Repo.Commit.CommitsCount()
+		ctx.Repo.CommitsCount, err = ctx.Repo.GetCommitsCount()
 		if err != nil {
-			ctx.Handle(500, "CommitsCount", err)
+			ctx.Handle(500, "GetCommitsCount", err)
 			return
 		}
 		ctx.Data["CommitsCount"] = ctx.Repo.CommitsCount
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 9787e09280..6c89381f3b 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -325,11 +325,6 @@ var (
 	// Time settings
 	TimeFormat string
 
-	// Cache settings
-	CacheAdapter  string
-	CacheInterval int
-	CacheConn     string
-
 	// Session settings
 	SessionConfig  session.Options
 	CSRFCookieName = "_csrf"
@@ -1295,16 +1290,33 @@ func NewXORMLogService(disableConsole bool) {
 	}
 }
 
+// Cache represents cache settings
+type Cache struct {
+	Adapter  string
+	Interval int
+	Conn     string
+	TTL      time.Duration
+}
+
+var (
+	// CacheService the global cache
+	CacheService *Cache
+)
+
 func newCacheService() {
-	CacheAdapter = Cfg.Section("cache").Key("ADAPTER").In("memory", []string{"memory", "redis", "memcache"})
-	switch CacheAdapter {
+	sec := Cfg.Section("cache")
+	CacheService = &Cache{
+		Adapter: sec.Key("ADAPTER").In("memory", []string{"memory", "redis", "memcache"}),
+	}
+	switch CacheService.Adapter {
 	case "memory":
-		CacheInterval = Cfg.Section("cache").Key("INTERVAL").MustInt(60)
+		CacheService.Interval = sec.Key("INTERVAL").MustInt(60)
 	case "redis", "memcache":
-		CacheConn = strings.Trim(Cfg.Section("cache").Key("HOST").String(), "\" ")
+		CacheService.Conn = strings.Trim(sec.Key("HOST").String(), "\" ")
 	default:
-		log.Fatal(4, "Unknown cache adapter: %s", CacheAdapter)
+		log.Fatal(4, "Unknown cache adapter: %s", CacheService.Adapter)
 	}
+	CacheService.TTL = sec.Key("ITEM_TTL").MustDuration(16 * time.Hour)
 
 	log.Info("Cache Service Enabled")
 }