podinfo/pkg/server/server.go

package server

import (
	"net/http"
	"os"
	"runtime"
	"strconv"

	"gopkg.in/yaml.v2"
)

type Server struct {
	mux *http.ServeMux
}

func New(options ...func(*Server)) *Server {
	s := &Server{mux: http.NewServeMux()}

	for _, f := range options {
		f(s)
	}

	s.mux.HandleFunc("/", s.index)
	s.mux.HandleFunc("/healthz/", s.healthz)

	return s
}

func (s *Server) index(w http.ResponseWriter, r *http.Request) {
	runtime := map[string]string{
		"os":            runtime.GOOS,
		"arch":          runtime.GOARCH,
		"version":       runtime.Version(),
		"max_procs":     strconv.FormatInt(int64(runtime.GOMAXPROCS(0)), 10),
		"num_goroutine": strconv.FormatInt(int64(runtime.NumGoroutine()), 10),
		"num_cpu":       strconv.FormatInt(int64(runtime.NumCPU()), 10),
	}
	runtime["hostname"], _ = os.Hostname()

	resp := &Response{
		Environment: os.Environ(),
		Runtime:     runtime,
	}

	d, err := yaml.Marshal(resp)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
	}

	w.Header().Set("Content-Type", "text/x-yaml")
	w.Write(d)
}

func (s *Server) healthz(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)
	w.Write([]byte("OK"))
}

func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Server", runtime.Version())

	s.mux.ServeHTTP(w, r)
}