sdk/go/httpserver/logger.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         "bufio"
   9         "context"
  10         "net"
  11         "net/http"
  12         "sync"
  13         "time"
  14
  15         "git.arvados.org/arvados.git/sdk/go/ctxlog"
  16         "git.arvados.org/arvados.git/sdk/go/stats"
  17         "github.com/sirupsen/logrus"
  18 )
  19
  20 type contextKey struct {
  21         name string
  22 }
  23
  24 var (
  25         requestTimeContextKey       = contextKey{"requestTime"}
  26         responseLogFieldsContextKey = contextKey{"responseLogFields"}
  27         mutexContextKey             = contextKey{"mutex"}
  28 )
  29
  30 type hijacker interface {
  31         http.ResponseWriter
  32         http.Hijacker
  33 }
  34
  35 // hijackNotifier wraps a ResponseWriter, calling the provided
  36 // Notify() func if/when the wrapped Hijacker is hijacked.
  37 type hijackNotifier struct {
  38         hijacker
  39         hijacked chan<- bool
  40 }
  41
  42 func (hn hijackNotifier) Hijack() (net.Conn, *bufio.ReadWriter, error) {
  43         close(hn.hijacked)
  44         return hn.hijacker.Hijack()
  45 }
  46
  47 // HandlerWithDeadline cancels the request context if the request
  48 // takes longer than the specified timeout without having its
  49 // connection hijacked.
  50 func HandlerWithDeadline(timeout time.Duration, next http.Handler) http.Handler {
  51         return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  52                 ctx, cancel := context.WithCancel(r.Context())
  53                 defer cancel()
  54                 nodeadline := make(chan bool)
  55                 go func() {
  56                         select {
  57                         case <-nodeadline:
  58                         case <-ctx.Done():
  59                         case <-time.After(timeout):
  60                                 cancel()
  61                         }
  62                 }()
  63                 if hj, ok := w.(hijacker); ok {
  64                         w = hijackNotifier{hj, nodeadline}
  65                 }
  66                 next.ServeHTTP(w, r.WithContext(ctx))
  67         })
  68 }
  69
  70 func SetResponseLogFields(ctx context.Context, fields logrus.Fields) {
  71         m := ctx.Value(&mutexContextKey)
  72         if mutex, ok := m.(sync.Mutex); ok {
  73                 mutex.Lock()
  74                 defer mutex.Unlock()
  75                 ctxfields := ctx.Value(&responseLogFieldsContextKey)
  76                 if c, ok := ctxfields.(logrus.Fields); ok {
  77                         for k, v := range fields {
  78                                 c[k] = v
  79                         }
  80                 }
  81         } else {
  82                 // We can't lock, don't set the fields
  83         }
  84 }
  85
  86 // LogRequests wraps an http.Handler, logging each request and
  87 // response.
  88 func LogRequests(h http.Handler) http.Handler {
  89         return http.HandlerFunc(func(wrapped http.ResponseWriter, req *http.Request) {
  90                 w := &responseTimer{ResponseWriter: WrapResponseWriter(wrapped)}
  91                 lgr := ctxlog.FromContext(req.Context()).WithFields(logrus.Fields{
  92                         "RequestID":       req.Header.Get("X-Request-Id"),
  93                         "remoteAddr":      req.RemoteAddr,
  94                         "reqForwardedFor": req.Header.Get("X-Forwarded-For"),
  95                         "reqMethod":       req.Method,
  96                         "reqHost":         req.Host,
  97                         "reqPath":         req.URL.Path[1:],
  98                         "reqQuery":        req.URL.RawQuery,
  99                         "reqBytes":        req.ContentLength,
 100                 })
 101                 ctx := req.Context()
 102                 ctx = context.WithValue(ctx, &requestTimeContextKey, time.Now())
 103                 ctx = context.WithValue(ctx, &responseLogFieldsContextKey, logrus.Fields{})
 104                 ctx = context.WithValue(ctx, &mutexContextKey, sync.Mutex{})
 105                 ctx = ctxlog.Context(ctx, lgr)
 106                 req = req.WithContext(ctx)
 107
 108                 logRequest(w, req, lgr)
 109                 defer logResponse(w, req, lgr)
 110                 h.ServeHTTP(rewrapResponseWriter(w, wrapped), req)
 111         })
 112 }
 113
 114 // Rewrap w to restore additional interfaces provided by wrapped.
 115 func rewrapResponseWriter(w http.ResponseWriter, wrapped http.ResponseWriter) http.ResponseWriter {
 116         if hijacker, ok := wrapped.(http.Hijacker); ok {
 117                 return struct {
 118                         http.ResponseWriter
 119                         http.Hijacker
 120                 }{w, hijacker}
 121         }
 122         return w
 123 }
 124
 125 func Logger(req *http.Request) logrus.FieldLogger {
 126         return ctxlog.FromContext(req.Context())
 127 }
 128
 129 func logRequest(w *responseTimer, req *http.Request, lgr *logrus.Entry) {
 130         lgr.Info("request")
 131 }
 132
 133 func logResponse(w *responseTimer, req *http.Request, lgr *logrus.Entry) {
 134         if tStart, ok := req.Context().Value(&requestTimeContextKey).(time.Time); ok {
 135                 tDone := time.Now()
 136                 writeTime := w.writeTime
 137                 if !w.wrote {
 138                         // Empty response body. Header was sent when
 139                         // handler exited.
 140                         writeTime = tDone
 141                 }
 142                 lgr = lgr.WithFields(logrus.Fields{
 143                         "timeTotal":     stats.Duration(tDone.Sub(tStart)),
 144                         "timeToStatus":  stats.Duration(writeTime.Sub(tStart)),
 145                         "timeWriteBody": stats.Duration(tDone.Sub(writeTime)),
 146                 })
 147         }
 148         if responseLogFields, ok := req.Context().Value(&responseLogFieldsContextKey).(logrus.Fields); ok {
 149                 lgr = lgr.WithFields(responseLogFields)
 150         }
 151         respCode := w.WroteStatus()
 152         if respCode == 0 {
 153                 respCode = http.StatusOK
 154         }
 155         fields := logrus.Fields{
 156                 "respStatusCode": respCode,
 157                 "respStatus":     http.StatusText(respCode),
 158                 "respBytes":      w.WroteBodyBytes(),
 159         }
 160         if respCode >= 400 {
 161                 fields["respBody"] = string(w.Sniffed())
 162         }
 163         lgr.WithFields(fields).Info("response")
 164 }
 165
 166 type responseTimer struct {
 167         ResponseWriter
 168         wrote     bool
 169         writeTime time.Time
 170 }
 171
 172 func (rt *responseTimer) CloseNotify() <-chan bool {
 173         if cn, ok := rt.ResponseWriter.(http.CloseNotifier); ok {
 174                 return cn.CloseNotify()
 175         }
 176         return nil
 177 }
 178
 179 func (rt *responseTimer) WriteHeader(code int) {
 180         if !rt.wrote {
 181                 rt.wrote = true
 182                 rt.writeTime = time.Now()
 183         }
 184         rt.ResponseWriter.WriteHeader(code)
 185 }
 186
 187 func (rt *responseTimer) Write(p []byte) (int, error) {
 188         if !rt.wrote {
 189                 rt.wrote = true
 190                 rt.writeTime = time.Now()
 191         }
 192         return rt.ResponseWriter.Write(p)
 193 }