Use global lock instead of NewExclusivePool to allow distributed lock between multiple Gitea instances (#31813)

Replace #26486 
Fix #19620

---------

Co-authored-by: Jason Song <i@wolfogre.com>

modules/setting/gloabl_lock.go

@@ -0,0 +1,37 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/nosql"
+)
+
+// GlobalLock represents configuration of global lock
+var GlobalLock = struct {
+	ServiceType    string
+	ServiceConnStr string
+}{
+	ServiceType: "memory",
+}
+
+func loadGlobalLockFrom(rootCfg ConfigProvider) {
+	sec := rootCfg.Section("global_lock")
+	GlobalLock.ServiceType = sec.Key("SERVICE_TYPE").MustString("memory")
+	switch GlobalLock.ServiceType {
+	case "memory":
+	case "redis":
+		connStr := sec.Key("SERVICE_CONN_STR").String()
+		if connStr == "" {
+			log.Fatal("SERVICE_CONN_STR is empty for redis")
+		}
+		u := nosql.ToRedisURI(connStr)
+		if u == nil {
+			log.Fatal("SERVICE_CONN_STR %s is not a valid redis connection string", connStr)
+		}
+		GlobalLock.ServiceConnStr = connStr
+	default:
+		log.Fatal("Unknown sync lock service type: %s", GlobalLock.ServiceType)
+	}
+}

modules/setting/global_lock_test.go

@@ -0,0 +1,35 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoadGlobalLockConfig(t *testing.T) {
+	t.Run("DefaultGlobalLockConfig", func(t *testing.T) {
+		iniStr := ``
+		cfg, err := NewConfigProviderFromData(iniStr)
+		assert.NoError(t, err)
+
+		loadGlobalLockFrom(cfg)
+		assert.EqualValues(t, "memory", GlobalLock.ServiceType)
+	})
+
+	t.Run("RedisGlobalLockConfig", func(t *testing.T) {
+		iniStr := `
+[global_lock]
+SERVICE_TYPE = redis
+SERVICE_CONN_STR = addrs=127.0.0.1:6379 db=0
+`
+		cfg, err := NewConfigProviderFromData(iniStr)
+		assert.NoError(t, err)
+
+		loadGlobalLockFrom(cfg)
+		assert.EqualValues(t, "redis", GlobalLock.ServiceType)
+		assert.EqualValues(t, "addrs=127.0.0.1:6379 db=0", GlobalLock.ServiceConnStr)
+	})
+}

modules/setting/setting.go

@@ -147,6 +147,7 @@ func loadCommonSettingsFrom(cfg ConfigProvider) error {
 	loadGitFrom(cfg)
 	loadMirrorFrom(cfg)
 	loadMarkupFrom(cfg)
+	loadGlobalLockFrom(cfg)
 	loadOtherFrom(cfg)
 	return nil
 }