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