show_gke_node_hostname.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		client := &http.Client{}

		req, err := http.NewRequest("GET", "http://metadata.google.internal/computeMetadata/v1/instance/hostname", nil)
		req.Header.Add("Metadata-Flavor", "Google")
		if err != nil {
			log.Println(err)
			fmt.Fprintf(w, "Error\n")
			return
		}

		resp, err := client.Do(req)
		if err != nil {
			log.Println(err)
			fmt.Fprintf(w, "Error\n")
			return
		}
		defer resp.Body.Close()

		b, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			log.Println(err)
			fmt.Fprintf(w, "Error\n")
			return
		}
		fmt.Fprintf(w, "NodeHostname: %s\n", string(b))
	})

	log.Fatal(http.ListenAndServe(":8080", nil))
}