pihole-exporter/internal/server/server.go
2021-12-21 14:59:21 +01:00

95 lines
2.2 KiB
Go

package server
import (
"fmt"
"log"
"net/http"
"strconv"
"strings"
"time"
"github.com/eko/pihole-exporter/internal/pihole"
"github.com/prometheus/client_golang/prometheus/promhttp"
"golang.org/x/net/context"
)
// Server is the struct for the HTTP server.
type Server struct {
httpServer *http.Server
}
// NewServer method initializes a new HTTP server instance and associates
// the different routes that will be used by Prometheus (metrics) or for monitoring (readiness, liveness).
func NewServer(port uint16, clients []*pihole.Client) *Server {
mux := http.NewServeMux()
httpServer := &http.Server{Addr: ":" + strconv.Itoa(int(port)), Handler: mux}
s := &Server{
httpServer: httpServer,
}
mux.HandleFunc("/metrics",
func(writer http.ResponseWriter, request *http.Request) {
errors := make([]string, 0)
for _, client := range clients {
if err := client.CollectMetrics(writer, request); err != nil {
errors = append(errors, err.Error())
fmt.Printf("Error %s\n", err)
}
}
if len(errors) == len(clients) {
writer.WriteHeader(http.StatusBadRequest)
body := strings.Join(errors, "\n")
_, _ = writer.Write([]byte(body))
}
promhttp.Handler().ServeHTTP(writer, request)
},
)
mux.Handle("/readiness", s.readinessHandler())
mux.Handle("/liveness", s.livenessHandler())
return s
}
// ListenAndServe method serves HTTP requests.
func (s *Server) ListenAndServe() {
log.Println("Starting HTTP server")
err := s.httpServer.ListenAndServe()
if err != nil {
log.Printf("Failed to start serving HTTP requests: %v", err)
}
}
// Stop method stops the HTTP server (so the exporter become unavailable).
func (s *Server) Stop() {
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
s.httpServer.Shutdown(ctx)
}
func (s *Server) readinessHandler() http.HandlerFunc {
return func(w http.ResponseWriter, req *http.Request) {
if s.isReady() {
w.WriteHeader(http.StatusOK)
} else {
w.WriteHeader(http.StatusNotFound)
}
}
}
func (s *Server) livenessHandler() http.HandlerFunc {
return func(w http.ResponseWriter, req *http.Request) {
w.WriteHeader(http.StatusOK)
}
}
func (s *Server) isReady() bool {
return s.httpServer != nil
}