golang设计模式-以kubernetes源码为例.pdf

golang设计模式-以kubernetes源码为例 概述 design pattern 介绍设计模式 engineer pattern 总结先进的⼯程模式 design pattern 参考 simplefactory 对golang来说就是Newxx函数，返回interface， kubernetes interface随处可见，可以说能⽤interface抽象的就是interface，随便举⼀ 个例⼦ // k8s.io/kubernetes/vendor/k8s.io/client-go/tools/cache/store.go func NewStore(keyFunc KeyFunc) Store { return &cache{ cacheStorage: NewThreadSafeStore(Indexers{}, Indices{}), keyFunc: keyFunc, } } type cache struct { // cacheStorage bears the burden of thread safety for the cache cacheStorage ThreadSafeStore // keyFunc is used to make the key for objects stored in and retrieved from items, and // should be deterministic. keyFunc KeyFunc } type Store interface { Add(obj interface{}) error Update(obj interface{}) error Delete(obj interface{}) error List() []interface{} ListKeys() []string Get(obj interface{}) (item interface{}, exists bool, err error) GetByKey(key string) (item interface{}, exists bool, err error) // Replace will delete the contents of the store, using instead the // given list. Store takes ownership of the list, you should not reference // it after calling this function. Replace([]interface{}, string) error Resync() error }复制代码 facade / adapter / decorator / delegate / bridge / mediator / composite 组合模式的不同形式，这些随处可见，也不⽤深究其中的区别。 singleton kubernetes/golang ⽤得很少，⼀般使⽤全局变量(如配置) (⽐如 net/http package 的 http.DefaultClient 和 http.DefaultServeMux). 或者作为context传递。 实现⽅式可以参考 ⽐较常见的⼀种⽅式是double check func GetInstance() *singleton { if instance == nil { // <-- Not yet perfect. since it's not fully atomic mu.Lock() defer mu.Unlock() if instance == nil { instance = &singleton{} } } return instance }复制代码 但是在golang⾥⾯有更好的⼀种⽅式，⽤"Once" type singleton struct { } var instance *s