first-commit

modules/globallock/globallock.go

@@ -0,0 +1,74 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package globallock
+
+import (
+	"context"
+	"sync"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+var (
+	defaultLocker Locker
+	initOnce      sync.Once
+	initFunc      = func() {
+		switch setting.GlobalLock.ServiceType {
+		case "redis":
+			defaultLocker = NewRedisLocker(setting.GlobalLock.ServiceConnStr)
+		case "memory":
+			fallthrough
+		default:
+			defaultLocker = NewMemoryLocker()
+		}
+	} // define initFunc as a variable to make it possible to change it in tests
+)
+
+// DefaultLocker returns the default locker.
+func DefaultLocker() Locker {
+	initOnce.Do(func() {
+		initFunc()
+	})
+	return defaultLocker
+}
+
+// Lock tries to acquire a lock for the given key, it uses the default locker.
+// Read the documentation of Locker.Lock for more information about the behavior.
+func Lock(ctx context.Context, key string) (ReleaseFunc, error) {
+	return DefaultLocker().Lock(ctx, key)
+}
+
+// TryLock tries to acquire a lock for the given key, it uses the default locker.
+// Read the documentation of Locker.TryLock for more information about the behavior.
+func TryLock(ctx context.Context, key string) (bool, ReleaseFunc, error) {
+	return DefaultLocker().TryLock(ctx, key)
+}
+
+// LockAndDo tries to acquire a lock for the given key and then calls the given function.
+// It uses the default locker, and it will return an error if failed to acquire the lock.
+func LockAndDo(ctx context.Context, key string, f func(context.Context) error) error {
+	release, err := Lock(ctx, key)
+	if err != nil {
+		return err
+	}
+	defer release()
+
+	return f(ctx)
+}
+
+// TryLockAndDo tries to acquire a lock for the given key and then calls the given function.
+// It uses the default locker, and it will return false if failed to acquire the lock.
+func TryLockAndDo(ctx context.Context, key string, f func(context.Context) error) (bool, error) {
+	ok, release, err := TryLock(ctx, key)
+	if err != nil {
+		return false, err
+	}
+	defer release()
+
+	if !ok {
+		return false, nil
+	}
+
+	return true, f(ctx)
+}