Refactor StatsRecorder

Signed-off-by: Emile Vauge <emile@vauge.com>

stats.go

@@ -1,85 +0,0 @@
-package main
-
-import (
-	"net/http"
-	"sync"
-	"time"
-)
-
-// StatsRecorder is an optional middleware that records more details statistics
-// about requests and how they are processed. This currently consists of recent
-// requests that have caused errors (4xx and 5xx status codes), making it easy
-// to pinpoint problems.
-type StatsRecorder struct {
-	mutex           sync.RWMutex
-	numRecentErrors int
-	recentErrors    []*statsError
-}
-
-// Stats includes all of the stats gathered by the recorder.
-type Stats struct {
-	RecentErrors []*statsError `json:"recent_errors"`
-}
-
-// statsError represents an error that has occurred during request processing.
-type statsError struct {
-	StatusCode int       `json:"status_code"`
-	Status     string    `json:"status"`
-	Method     string    `json:"method"`
-	Host       string    `json:"host"`
-	Path       string    `json:"path"`
-	Time       time.Time `json:"time"`
-}
-
-// responseRecorder captures information from the response and preserves it for
-// later analysis.
-type responseRecorder struct {
-	http.ResponseWriter
-	statusCode int
-}
-
-// WriteHeader captures the status code for later retrieval.
-func (r *responseRecorder) WriteHeader(status int) {
-	r.ResponseWriter.WriteHeader(status)
-	r.statusCode = status
-}
-
-// ServeHTTP silently extracts information from the request and response as it
-// is processed. If the response is 4xx or 5xx, add it to the list of 10 most
-// recent errors.
-func (s *StatsRecorder) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
-	recorder := &responseRecorder{w, http.StatusOK}
-	next(recorder, r)
-	if recorder.statusCode >= 400 {
-		s.mutex.Lock()
-		defer s.mutex.Unlock()
-		s.recentErrors = append([]*statsError{
-			{
-				StatusCode: recorder.statusCode,
-				Status:     http.StatusText(recorder.statusCode),
-				Method:     r.Method,
-				Host:       r.Host,
-				Path:       r.URL.Path,
-				Time:       time.Now(),
-			},
-		}, s.recentErrors...)
-		// Limit the size of the list to numRecentErrors
-		if len(s.recentErrors) > s.numRecentErrors {
-			s.recentErrors = s.recentErrors[:s.numRecentErrors]
-		}
-	}
-}
-
-// Data returns a copy of the statistics that have been gathered.
-func (s *StatsRecorder) Data() *Stats {
-	s.mutex.RLock()
-	defer s.mutex.RUnlock()
-
-	// We can't return the slice directly or a race condition might develop
-	recentErrors := make([]*statsError, len(s.recentErrors))
-	copy(recentErrors, s.recentErrors)
-
-	return &Stats{
-		RecentErrors: recentErrors,
-	}
-}