序
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定義了Name、Clusters、CacheMillis、LastRefMillis、Instances、Env、TTL屬性；它提供了getInstances、String、SrvInstances方法；其中SrvInstances方法根據instance的權重來返回對應個數的instance
實例
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()
}
這裏設置instances爲一個weight爲2的instance，然後通過SrvInstances方法返回2個instance
小結
nacos-coredns-plugin的Domain定義了Name、Clusters、CacheMillis、LastRefMillis、Instances、Env、TTL屬性；它提供了getInstances、String、SrvInstances方法。