client.go

// Copyright Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// This example is adapted from:
// https://github.com/aspenmesh/istio-client-go/blob/4de6e89009c427dbc602b0c6bbdc8840ef1905e6/cmd/example-client/client.go

package main

import (
	"context"
	"log"
	"os"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/tools/clientcmd"

	versionedclient "istio.io/client-go/pkg/clientset/versioned"
)

func main() {
	kubeconfig := os.Getenv("KUBECONFIG")
	namespace := os.Getenv("NAMESPACE")

	if len(kubeconfig) == 0 || len(namespace) == 0 {
		log.Fatalf("Environment variables KUBECONFIG and NAMESPACE need to be set")
	}

	restConfig, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
	if err != nil {
		log.Fatalf("Failed to create k8s rest client: %s", err)
	}

	ic, err := versionedclient.NewForConfig(restConfig)
	if err != nil {
		log.Fatalf("Failed to create istio client: %s", err)
	}

	// Test VirtualServices
	vsList, err := ic.NetworkingV1alpha3().VirtualServices(namespace).List(context.TODO(), metav1.ListOptions{})
	if err != nil {
		log.Fatalf("Failed to get VirtualService in %s namespace: %s", namespace, err)
	}

	for i := range vsList.Items {
		vs := vsList.Items[i]
		log.Printf("Index: %d VirtualService Hosts: %+v\n", i, vs.Spec.GetHosts())
	}

	// Test DestinationRules
	drList, err := ic.NetworkingV1alpha3().DestinationRules(namespace).List(context.TODO(), metav1.ListOptions{})
	if err != nil {
		log.Fatalf("Failed to get DestinationRule in %s namespace: %s", namespace, err)
	}

	for i := range drList.Items {
		dr := drList.Items[i]
		log.Printf("Index: %d DestinationRule Host: %+v\n", i, dr.Spec.GetHost())
	}

	// Test Gateway
	gwList, err := ic.NetworkingV1alpha3().Gateways(namespace).List(context.TODO(), metav1.ListOptions{})
	if err != nil {
		log.Fatalf("Failed to get Gateway in %s namespace: %s", namespace, err)
	}

	for i := range gwList.Items {
		gw := gwList.Items[i]
		for _, s := range gw.Spec.GetServers() {
			log.Printf("Index: %d Gateway servers: %+v\n", i, s)
		}
	}

	// Test ServiceEntry
	seList, err := ic.NetworkingV1alpha3().ServiceEntries(namespace).List(context.TODO(), metav1.ListOptions{})
	if err != nil {
		log.Fatalf("Failed to get ServiceEntry in %s namespace: %s", namespace, err)
	}

	for i := range seList.Items {
		se := seList.Items[i]
		for _, h := range se.Spec.GetHosts() {
			log.Printf("Index: %d ServiceEntry hosts: %+v\n", i, h)
		}
	}
}