观察者
我们支持使用分布式消息系统，例如 etcd 来保持多个Casbin执行器实例之间的一致性。 因此，我们的用户可以同时使用多个Casbin 执行器来处理大量的权限检查请求。

与策略存储 adapters类似，我们没有把watcher的代码放在主库中。 任何对新消息系统的支持都应该作为watcher程序来实现。 完整的Casbin watchers列表如下所示。 欢迎任何第三方对 watcher 进行新的贡献，如果有请告知我们，我将把它放在这个列表中:)

Go

** 监视器** 类型 作者 说明
Etcd Watcher KV store Casbin etcd 的监视器
Redis Watcher KV store Casbin Watcher for Redis
Redis Watcher KV store @billcobbler Watcher for Redis
Kafka Watcher Messaging system @wgarunap Watcher for Apache Kafka
NATS Watcher Messaging system Soluto Watcher for NATS
ZooKeeper Watcher Messaging system Grepsr Watcher for Apache ZooKeeper
NATS, RabbitMQ, GCP Pub/Sub, AWS SNS & SQS, Kafka, InMemory Messaging System @rusenask Watcher based on Go Cloud Dev Kit that works with leading cloud providers and self-hosted infrastructure
RocketMQ Watcher Messaging system @fmyxyz Watcher for Apache RocketMQ

WatcherEx

In order to support incremental synchronization between multiple instances, we provide the WatcherEx interface. We hope it can notify other instances when the policy changes, but there is currently no implementation of WatcherEx. We recommend that you use dispatcher to achieve this.

Compared with Watcher interface, with implementing WatcherEx what kind of update action can be distinguished, etc AddPolicy, RemovePolicy, etc.

WatcherEx Apis:

api description
SetUpdateCallback(func(string)) error SetUpdateCallback sets the callback function that the watcher will call, when the policy in DB has been changed by other instances. A classic callback is Enforcer.LoadPolicy().
Update() error Update calls the update callback of other instances to synchronize their policy. It is usually called after changing the policy in DB, like Enforcer.SavePolicy(), Enforcer.AddPolicy(), Enforcer.RemovePolicy(), etc.
Close() Close stops and releases the watcher, the callback function will not be called any more.
UpdateForAddPolicy(params …string) error UpdateForAddPolicy calls the update callback of other instances to synchronize their policy. It is called after Enforcer.AddPolicy()
UpdateForRemoveFilteredPolicy(fieldIndex int, fieldValues …string) error UpdateForRemoveFilteredPolicy calls the update callback of other instances to synchronize their policy. It is called after Enforcer.RemoveFilteredNamedGroupingPolicy()
UpdateForSavePolicy(model model.Model) error UpdateForSavePolicy calls the update callback of other instances to synchronize their policy. It is called after Enforcer.RemoveFilteredNamedGroupingPolicy()
最后编辑: kuteng  文档更新时间: 2021-06-22 19:03   作者：kuteng