聊聊nacos-coredns-plugin的Domain

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本文主要研究一下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方法;其中SrvInstances方法根据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,然后通过SrvInstances方法返回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方法。

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