关于golang:聊聊nacoscorednsplugin的Domain

序

本文次要钻研一下 nacos-coredns-plugin 的 Domain

Domain

nacos-coredns-plugin/nacos/nacos_domain.go

type Domain struct {
    Name string `json:"dom"`
    Clusters string
    CacheMillis int64
    LastRefMillis int64
    Instances []Instance `json:"hosts"`
    Env string
    TTL int

}

func (domain Domain) getInstances() ([]Instance) {return domain.Instances}

func (domain Domain) String() string {b, _ := json.Marshal(domain)
    return string(b)
}

func (domain Domain) SrvInstances() []Instance {var result = make([]Instance, 0)
    hosts := domain.getInstances()
    for _, host := range hosts {
        if host.Valid && host.Weight > 0 {for i := 0; i < int(math.Ceil(host.Weight)); i++ {result = append(result, host)
            }
        }
    }

    if len(result) <= 0{panic("no host to srv:" + domain.Name)
    }

    return result
}

Domain 定义了 Name、Clusters、CacheMillis、LastRefMillis、Instances、Env、TTL 属性；它提供了 getInstances、String、SrvInstances 办法；其中 SrvInstances 办法依据 instance 的权重来返回对应个数的 instance

实例

nacos-coredns-plugin/nacos/nacos_domain_test.go

func TestDomain_SrvInstances(t *testing.T) {domain := Domain{}
    domain.CacheMillis = 10000
    domain.Clusters = "DEFAULT"

    //test weight
    domain.Instances = []Instance{Instance{IP: "2.2.2.2", Port: 80, Weight: 2, AppUseType: "publish", Valid: true, Site: "et2"}}
    instances := domain.SrvInstances()
    if len(instances) == 2 {t.Log("Domain.srvInstances weight passed.")
    }

    //test valid
    defer func() {if err := recover(); err != nil {if strings.HasPrefix(err.(string), "no host to srv:") {t.Log("Domain.srvInstances valid passed.")
            }
        }
    }()
    domain.Instances = []Instance{Instance{IP: "2.2.2.2", Port: 80, Weight: 2, AppUseType: "publish", Valid: false, Site: "et2"}}
    domain.SrvInstances()}

这里设置 instances 为一个 weight 为 2 的 instance，而后通过 SrvInstances 办法返回 2 个 instance

小结

nacos-coredns-plugin 的 Domain 定义了 Name、Clusters、CacheMillis、LastRefMillis、Instances、Env、TTL 属性；它提供了 getInstances、String、SrvInstances 办法。

doc

• nacos-coredns-plugin