dipankardas011/main.go

## main.go
package main

import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"time"

	"k8s.io/client-go/tools/clientcmd"
)

const (
	LocationCaCert     = "/tmp/ca.crt"
	LocationClientCert = "/tmp/client.crt"
	LocationClientKey  = "/tmp/client.pem"
)

func Write(fileName string, data []byte) error {
	return os.WriteFile(fileName, data, 0770)
}

func HttpClient() (*http.Client, error) {

	caCert, err := os.ReadFile(LocationCaCert)
	if err != nil {
		fmt.Println("Error reading CA certificate:", err)
		return nil, err
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)

	cert, err := tls.LoadX509KeyPair(LocationClientCert, LocationClientKey)
	if err != nil {
		fmt.Println("Error loading client certificate and key:", err)
		return nil, err
	}

	tlsConfig := &tls.Config{
		RootCAs:      caCertPool,
		Certificates: []tls.Certificate{cert},
	}
	tr := &http.Transport{
		TLSClientConfig: tlsConfig,
	}
	client := &http.Client{Transport: tr, Timeout: 1 * time.Minute}
	return client, nil
}

func main() {
	config, err := clientcmd.LoadFromFile("/home/dipankar/.kube/config")
	if err != nil {
		log.Fatalf("Failed to load kubeconfig file: %v", err)
	}

	cluster := config.Clusters["kind-kind"]
	usr := config.AuthInfos["kind-kind"]

	kubeapiURL := cluster.Server

	if _err := Write(LocationCaCert, cluster.CertificateAuthorityData); _err != nil {
		panic(_err)
	}

	if _err := Write(LocationClientCert, usr.ClientCertificateData); _err != nil {
		panic(_err)
	}

	if _err := Write(LocationClientKey, usr.ClientKeyData); _err != nil {
		panic(_err)
	}

	req, err := http.NewRequest(http.MethodGet, kubeapiURL+"/api/v1/namespaces/default/services/abcd:80/proxy/", nil)
	if err != nil {
		fmt.Printf("client: could not create request: %s\n", err)
		os.Exit(1)
	}

	client, err := HttpClient()
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	res, err := client.Do(req)
	if err != nil {
		fmt.Printf("client: error making http request: %s\n", err)
		os.Exit(1)
	}

	body, err := io.ReadAll(res.Body)
	if err != nil {
		panic(err)
	}

	fmt.Println("Response:", string(body))
}

## output
$ kubectl run abcd --image=nginx
$ kubectl expose pod abcd --port 80


Response: <!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
	package main

	import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"time"

	"k8s.io/client-go/tools/clientcmd"
	)

	const (
	LocationCaCert = "/tmp/ca.crt"
	LocationClientCert = "/tmp/client.crt"
	LocationClientKey = "/tmp/client.pem"
	)

	func Write(fileName string, data []byte) error {
	return os.WriteFile(fileName, data, 0770)
	}

	func HttpClient() (*http.Client, error) {

	caCert, err := os.ReadFile(LocationCaCert)
	if err != nil {
	fmt.Println("Error reading CA certificate:", err)
	return nil, err
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)

	cert, err := tls.LoadX509KeyPair(LocationClientCert, LocationClientKey)
	if err != nil {
	fmt.Println("Error loading client certificate and key:", err)
	return nil, err
	}

	tlsConfig := &tls.Config{
	RootCAs: caCertPool,
	Certificates: []tls.Certificate{cert},
	}
	tr := &http.Transport{
	TLSClientConfig: tlsConfig,
	}
	client := &http.Client{Transport: tr, Timeout: 1 * time.Minute}
	return client, nil
	}

	func main() {
	config, err := clientcmd.LoadFromFile("/home/dipankar/.kube/config")
	if err != nil {
	log.Fatalf("Failed to load kubeconfig file: %v", err)
	}

	cluster := config.Clusters["kind-kind"]
	usr := config.AuthInfos["kind-kind"]

	kubeapiURL := cluster.Server

	if _err := Write(LocationCaCert, cluster.CertificateAuthorityData); _err != nil {
	panic(_err)
	}

	if _err := Write(LocationClientCert, usr.ClientCertificateData); _err != nil {
	panic(_err)
	}

	if _err := Write(LocationClientKey, usr.ClientKeyData); _err != nil {
	panic(_err)
	}

	req, err := http.NewRequest(http.MethodGet, kubeapiURL+"/api/v1/namespaces/default/services/abcd:80/proxy/", nil)
	if err != nil {
	fmt.Printf("client: could not create request: %s\n", err)
	os.Exit(1)
	}

	client, err := HttpClient()
	if err != nil {
	fmt.Println(err)
	os.Exit(1)
	}

	res, err := client.Do(req)
	if err != nil {
	fmt.Printf("client: error making http request: %s\n", err)
	os.Exit(1)
	}

	body, err := io.ReadAll(res.Body)
	if err != nil {
	panic(err)
	}

	fmt.Println("Response:", string(body))
	}
	$ kubectl run abcd --image=nginx
	$ kubectl expose pod abcd --port 80


	Response: <!DOCTYPE html>
	<html>
	<head>
	<title>Welcome to nginx!</title>
	<style>
	html { color-scheme: light dark; }
	body { width: 35em; margin: 0 auto;
	font-family: Tahoma, Verdana, Arial, sans-serif; }
	</style>
	</head>
	<body>
	<h1>Welcome to nginx!</h1>
	<p>If you see this page, the nginx web server is successfully installed and
	working. Further configuration is required.</p>

	<p>For online documentation and support please refer to
	<a href="http://nginx.org/">nginx.org</a>.<br/>
	Commercial support is available at
	<a href="http://nginx.com/">nginx.com</a>.</p>

	<p><em>Thank you for using nginx.</em></p>
	</body>
	</html>