sdk/go/httpserver/metrics.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: Apache-2.0
   4
   5 package httpserver
   6
   7 import (
   8         "net/http"
   9         "strconv"
  10         "strings"
  11         "time"
  12
  13         "git.curoverse.com/arvados.git/sdk/go/stats"
  14         "github.com/Sirupsen/logrus"
  15         "github.com/gogo/protobuf/jsonpb"
  16         "github.com/prometheus/client_golang/prometheus"
  17         "github.com/prometheus/client_golang/prometheus/promhttp"
  18 )
  19
  20 type Handler interface {
  21         http.Handler
  22 }
  23
  24 type metrics struct {
  25         next         http.Handler
  26         logger       *logrus.Logger
  27         registry     *prometheus.Registry
  28         reqDuration  *prometheus.SummaryVec
  29         timeToStatus *prometheus.SummaryVec
  30         exportProm   http.Handler
  31 }
  32
  33 func (*metrics) Levels() []logrus.Level {
  34         return logrus.AllLevels
  35 }
  36
  37 func (m *metrics) Fire(ent *logrus.Entry) error {
  38         if tts, ok := ent.Data["timeToStatus"].(stats.Duration); !ok {
  39         } else if method, ok := ent.Data["reqMethod"].(string); !ok {
  40         } else if code, ok := ent.Data["respStatusCode"].(int); !ok {
  41         } else {
  42                 m.timeToStatus.WithLabelValues(strconv.Itoa(code), strings.ToLower(method)).Observe(time.Duration(tts).Seconds())
  43         }
  44         return nil
  45 }
  46
  47 func (m *metrics) exportJSON(w http.ResponseWriter, req *http.Request) {
  48         jm := jsonpb.Marshaler{Indent: "  "}
  49         mfs, _ := m.registry.Gather()
  50         w.Write([]byte{'['})
  51         for i, mf := range mfs {
  52                 if i > 0 {
  53                         w.Write([]byte{','})
  54                 }
  55                 jm.Marshal(w, mf)
  56         }
  57         w.Write([]byte{']'})
  58 }
  59
  60 func (m *metrics) ServeHTTP(w http.ResponseWriter, req *http.Request) {
  61         switch {
  62         case req.Method != "GET" && req.Method != "HEAD":
  63                 m.next.ServeHTTP(w, req)
  64         case req.URL.Path == "/metrics.json":
  65                 m.exportJSON(w, req)
  66         case req.URL.Path == "/metrics":
  67                 m.exportProm.ServeHTTP(w, req)
  68         default:
  69                 m.next.ServeHTTP(w, req)
  70         }
  71 }
  72
  73 func Instrument(logger *logrus.Logger, next http.Handler) Handler {
  74         if logger == nil {
  75                 logger = logrus.StandardLogger()
  76         }
  77         reqDuration := prometheus.NewSummaryVec(prometheus.SummaryOpts{
  78                 Name: "request_duration_seconds",
  79                 Help: "Summary of request duration.",
  80         }, []string{"code", "method"})
  81         timeToStatus := prometheus.NewSummaryVec(prometheus.SummaryOpts{
  82                 Name: "time_to_status_seconds",
  83                 Help: "Summary of request TTFB.",
  84         }, []string{"code", "method"})
  85         registry := prometheus.NewRegistry()
  86         registry.MustRegister(timeToStatus)
  87         registry.MustRegister(reqDuration)
  88         m := &metrics{
  89                 next:         promhttp.InstrumentHandlerDuration(reqDuration, next),
  90                 logger:       logger,
  91                 registry:     registry,
  92                 reqDuration:  reqDuration,
  93                 timeToStatus: timeToStatus,
  94                 exportProm: promhttp.HandlerFor(registry, promhttp.HandlerOpts{
  95                         ErrorLog: logger,
  96                 }),
  97         }
  98         m.logger.AddHook(m)
  99         return m
 100 }