tracker: record announce/scrape stats in handlers

This deduplicates code tracking the stats code tracking announces and
scrapes for each protocol. The down side is that it isn't aware of any
failures writing responses, but it was already being called before the
write to a response for HTTP.

http/routes.go

@@ -86,8 +86,6 @@ func handleTorrentError(err error, w *Writer) (int, error) {
 }
 
 func (s *Server) serveAnnounce(w http.ResponseWriter, r *http.Request, p httprouter.Params) (int, error) {
-	stats.RecordEvent(stats.Announce)
-
 	writer := &Writer{w}
 	ann, err := s.newAnnounce(r, p)
 	if err != nil {
@@ -98,8 +96,6 @@ func (s *Server) serveAnnounce(w http.ResponseWriter, r *http.Request, p httprou
 }
 
 func (s *Server) serveScrape(w http.ResponseWriter, r *http.Request, p httprouter.Params) (int, error) {
-	stats.RecordEvent(stats.Scrape)
-
 	writer := &Writer{w}
 	scrape, err := s.newScrape(r, p)
 	if err != nil {

tracker/announce.go

@@ -70,6 +70,7 @@ func (tkr *Tracker) HandleAnnounce(ann *models.Announce, w Writer) (err error) {
 		stats.RecordEvent(stats.DeletedTorrent)
 	}
 
+	stats.RecordEvent(stats.Announce)
 	return w.WriteAnnounce(newAnnounceResponse(ann))
 }
 

tracker/scrape.go

@@ -4,7 +4,10 @@
 
 package tracker
 
-import "github.com/chihaya/chihaya/tracker/models"
+import (
+	"github.com/chihaya/chihaya/stats"
+	"github.com/chihaya/chihaya/tracker/models"
+)
 
 // HandleScrape encapsulates all the logic of handling a BitTorrent client's
 // scrape without being coupled to any transport protocol.
@@ -24,6 +27,7 @@ func (tkr *Tracker) HandleScrape(scrape *models.Scrape, w Writer) (err error) {
 		torrents = append(torrents, torrent)
 	}
 
+	stats.RecordEvent(stats.Scrape)
 	return w.WriteScrape(&models.ScrapeResponse{
 		Files: torrents,
 	})