frontend: make request timing optional

example_config.yaml

@@ -40,6 +40,10 @@ chihaya:
     read_timeout: 5s
     write_timeout: 5s
 
+    # Whether to time requests.
+    # Disabling this should increase performance/decrease load.
+    enable_request_timing: false
+
   # This block defines configuration for the tracker's UDP interface.
   # If you do not wish to run this, delete this section.
   udp:
@@ -57,6 +61,10 @@ chihaya:
     # The key used to encrypt connection IDs.
     private_key: "paste a random string here that will be used to hmac connection IDs"
 
+    # Whether to time requests.
+    # Disabling this should increase performance/decrease load.
+    enable_request_timing: false
+
   # This block defines configuration used for the storage of peer data.
   storage:
     # The frequency which stale peers are removed.

frontend/http/frontend.go

@@ -69,6 +69,7 @@ type Config struct {
 	RealIPHeader        string        `yaml:"real_ip_header"`
 	TLSCertPath         string        `yaml:"tls_cert_path"`
 	TLSKeyPath          string        `yaml:"tls_key_path"`
+	EnableRequestTiming bool          `yaml:"enable_request_timing"`
 }
 
 // LogFields renders the current config as a set of Logrus fields.
@@ -81,6 +82,7 @@ func (cfg Config) LogFields() log.Fields {
 		"realIPHeader":        cfg.RealIPHeader,
 		"tlsCertPath":         cfg.TLSCertPath,
 		"tlsKeyPath":          cfg.TLSKeyPath,
+		"enableRequestTiming": cfg.EnableRequestTiming,
 	}
 }
 
@@ -168,9 +170,18 @@ func (f *Frontend) listenAndServe() error {
 // announceRoute parses and responds to an Announce.
 func (f *Frontend) announceRoute(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 	var err error
-	start := time.Now()
+	var start time.Time
+	if f.EnableRequestTiming {
+		start = time.Now()
+	}
 	var af *bittorrent.AddressFamily
-	defer func() { recordResponseDuration("announce", af, err, time.Since(start)) }()
+	defer func() {
+		if f.EnableRequestTiming {
+			recordResponseDuration("announce", af, err, time.Since(start))
+		} else {
+			recordResponseDuration("announce", af, err, time.Duration(0))
+		}
+	}()
 
 	req, err := ParseAnnounce(r, f.RealIPHeader, f.AllowIPSpoofing)
 	if err != nil {
@@ -198,9 +209,18 @@ func (f *Frontend) announceRoute(w http.ResponseWriter, r *http.Request, _ httpr
 // scrapeRoute parses and responds to a Scrape.
 func (f *Frontend) scrapeRoute(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
 	var err error
-	start := time.Now()
+	var start time.Time
+	if f.EnableRequestTiming {
+		start = time.Now()
+	}
 	var af *bittorrent.AddressFamily
-	defer func() { recordResponseDuration("scrape", af, err, time.Since(start)) }()
+	defer func() {
+		if f.EnableRequestTiming {
+			recordResponseDuration("scrape", af, err, time.Since(start))
+		} else {
+			recordResponseDuration("scrape", af, err, time.Duration(0))
+		}
+	}()
 
 	req, err := ParseScrape(r)
 	if err != nil {

frontend/udp/frontend.go

@@ -71,6 +71,7 @@ type Config struct {
 	PrivateKey          string        `yaml:"private_key"`
 	MaxClockSkew        time.Duration `yaml:"max_clock_skew"`
 	AllowIPSpoofing     bool          `yaml:"allow_ip_spoofing"`
+	EnableRequestTiming bool          `yaml:"enable_request_timing"`
 }
 
 // LogFields renders the current config as a set of Logrus fields.
@@ -80,6 +81,7 @@ func (cfg Config) LogFields() log.Fields {
 		"privateKey":          cfg.PrivateKey,
 		"maxClockSkew":        cfg.MaxClockSkew,
 		"allowIPSpoofing":     cfg.AllowIPSpoofing,
+		"enableRequestTiming": cfg.EnableRequestTiming,
 	}
 }
 
@@ -201,13 +203,20 @@ func (t *Frontend) listenAndServe() error {
 			}
 
 			// Handle the request.
-			start := time.Now()
+			var start time.Time
+			if t.EnableRequestTiming {
+				start = time.Now()
+			}
 			action, af, err := t.handleRequest(
 				// Make sure the IP is copied, not referenced.
 				Request{buffer[:n], append([]byte{}, addr.IP...)},
 				ResponseWriter{t.socket, addr},
 			)
+			if t.EnableRequestTiming {
 				recordResponseDuration(action, af, err, time.Since(start))
+			} else {
+				recordResponseDuration(action, af, err, time.Duration(0))
+			}
 		}()
 	}
 }