client.go

package main

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

func main() {

	// Create a CA certificate pool and add the server cert chain pem file to it
	caCert, err := os.ReadFile("cert-chain.pem")
	if err != nil {
		log.Fatal(err)
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)

	// Read the key pair to create certificate
	cert, err := tls.LoadX509KeyPair("certs/partner-org.example.crt", "certs/partner-org.example.key")
	if err != nil {
		log.Fatal(err)
	}

	// Create a HTTPS client and supply the created CA pool
	client := &http.Client{
		Transport: &http.Transport{
			TLSClientConfig: &tls.Config{
				RootCAs:      caCertPool,
				Certificates: []tls.Certificate{cert},
			},
		},
	}

	// Request /zero via the created HTTPS client over port 8443 via GET
	r, err := client.Get("https://localhost:8443/zero")

	if err != nil {
		log.Fatal(err)
	}

	// Read the response body
	defer r.Body.Close()
	body, err := io.ReadAll(r.Body)
	if err != nil {
		_ = r.Body.Close()
		log.Fatal(err)
	}

	// Print the response body to stdout
	fmt.Printf("%s\n", body)
}