用来直接获取所有service的annotaion里有ambassador的东东。

或者，watch集群事件。

package main

import (
"fmt"
"os"
//"time"
"strings"

//"k8s.io/apimachinery/pkg/api/errors"
"k8s.io/api/core/v1"
    //"k8s.io/apimachinery/pkg/labels"
    //"k8s.io/apimachinery/pkg/watch"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
//
// Uncomment to load all auth plugins
// \_ "k8s.io/client-go/plugin/pkg/client/auth"
//
// Or uncomment to load specific auth plugins
// \_ "k8s.io/client-go/plugin/pkg/client/auth/azure"
// \_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
// \_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
// \_ "k8s.io/client-go/plugin/pkg/client/auth/openstack"

)

func main() {
// creates the in-cluster config
config, err := rest.InClusterConfig()
if err != nil {
panic(err.Error())
}
// creates the clientset
clientset, err := kubernetes.NewForConfig(config)
if err != nil {
panic(err.Error())
}

    // get pods in all the namespaces by omitting namespace
    // Or specify namespace to get pods in particular namespace
    services, err := clientset.CoreV1().Services("").List(metav1.ListOptions{})
    if err != nil {
        panic(err.Error())
    }
    for i:=0; i < len(services.Items); i++ {
        item := services.Items\[i\].Annotations
        for k, v := range item {
            if strings.Contains(k, "getambassador") && strings.Contains(v, "ambassador") && strings.Contains(v, "Mapping"){
                fmt.Println(v)
                fmt.Println("@@@@@@@@@@@@@@@@@@@@@@@")
            }
        }
    }

    //time.Sleep(10 \* time.Second)
    handleNewServices(clientset)

}

func handleNewServices(clientset *kubernetes.Clientset) {
for {
serviceStreamWatcher, err := clientset.CoreV1().Services("").Watch(metav1.ListOptions{})
if err != nil {
panic(err.Error())
}
fmt.Printf("%T\n", serviceStreamWatcher)
for {
select {
case event := <-serviceStreamWatcher.ResultChan():

                service := event.Object.(\*v1.Service)                                                                                                    

                for key, value := range service.Annotations {
                if strings.Contains(key, "getambassador") && strings.Contains(value, "ambassador") && strings.Contains(value, "Mapping"){
            toFileStr := fmt.Sprintf("%s\\n%s\\n=============\\n", event.Type, value)
                        //fmt.Println(toFileStr)
            \_appendToFile("/app/k8s-ambassador",  toFileStr)
                    }
                }
        }
    }
}

}

func _appendToFile(file, str string) {
f, err := os.OpenFile(file, os.O_CREATE|os.O_APPEND|os.O_RDWR, 0664)
if err != nil {
fmt.Printf("Cannot open file %s!\n", file)
return
}
defer f.Close()
f.WriteString(str)
}