Add system setting table with cache and also add cache supports for user setting (#18058)

modules/system/setting.go

@@ -0,0 +1,46 @@
+// Copyright 2021 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 system
+
+import (
+	"strconv"
+
+	"code.gitea.io/gitea/models/system"
+	"code.gitea.io/gitea/modules/cache"
+)
+
+func genKey(key string) string {
+	return "system.setting." + key
+}
+
+// GetSetting returns the setting value via the key
+func GetSetting(key string) (string, error) {
+	return cache.GetString(genKey(key), func() (string, error) {
+		res, err := system.GetSetting(key)
+		if err != nil {
+			return "", err
+		}
+		return res.SettingValue, nil
+	})
+}
+
+// GetSettingBool return bool value of setting,
+// none existing keys and errors are ignored and result in false
+func GetSettingBool(key string) bool {
+	s, _ := GetSetting(key)
+	b, _ := strconv.ParseBool(s)
+	return b
+}
+
+// SetSetting sets the setting value
+func SetSetting(key, value string, version int) error {
+	cache.Remove(genKey(key))
+
+	return system.SetSetting(&system.Setting{
+		SettingKey:   key,
+		SettingValue: value,
+		Version:      version,
+	})
+}