feat: measure each direction of the speed test for 7 s (0.0.7)

internal/agent/speed.go

@@ -13,24 +13,30 @@ import (
 )
 
 const (
-	// speedWindow is how long each direction is measured for.
-	speedWindow = 3 * time.Second
+	// speedWindow is how long each direction is measured for, unless the
+	// server asks for another window; speedWindowMax bounds what it may ask.
+	speedWindow    = 3 * time.Second
+	speedWindowMax = 30 * time.Second
 	// speedWait is how long the download may take to start: in a relayed test
 	// its bytes come from the browser.
 	speedWait = 10 * time.Second
-	// speedUpCap bounds the upload, whatever the link does in speedWindow.
+	// speedUpCap bounds the upload, whatever the link does in the window.
 	speedUpCap = 48 << 20
 )
 
 // doSpeed measures the agent's HTTP link to the server: round-trip time of an
-// empty request, then how much flows each way in speedWindow. In a relayed
+// empty request, then how much flows each way in the window. In a relayed
 // test the server pipes both streams to the browser, so they run end to end.
 func (a *Agent) doSpeed(ctx context.Context, env proto.TaskEnvelope) proto.TaskResult {
 	var args proto.SysSpeedArgs
 	if len(env.Args) > 0 {
 		_ = json.Unmarshal(env.Args, &args)
 	}
-	res, err := a.measureSpeed(ctx, args.Relay)
+	window := speedWindow
+	if args.WindowMs > 0 {
+		window = min(time.Duration(args.WindowMs)*time.Millisecond, speedWindowMax)
+	}
+	res, err := a.measureSpeed(ctx, args.Relay, window)
 	if err != nil {
 		return proto.TaskResult{Error: err.Error()}
 	}
@@ -38,7 +44,7 @@ func (a *Agent) doSpeed(ctx context.Context, env proto.TaskEnvelope) proto.TaskR
 	return proto.TaskResult{OK: true, Data: data}
 }
 
-func (a *Agent) measureSpeed(ctx context.Context, relay bool) (proto.SysSpeedResult, error) {
+func (a *Agent) measureSpeed(ctx context.Context, relay bool, window time.Duration) (proto.SysSpeedResult, error) {
 	res := proto.SysSpeedResult{Relay: relay}
 	streams := "/api/agent/speed"
 	if relay {
@@ -59,14 +65,14 @@ func (a *Agent) measureSpeed(ctx context.Context, relay bool) (proto.SysSpeedRes
 		}
 	}
 
-	down, err := a.speedDown(ctx, streams+"/down")
+	down, err := a.speedDown(ctx, streams+"/down", window)
 	if err != nil {
 		return res, err
 	}
 	res.DownBps = down
 
 	// Up: send until the window closes or the cap is hit.
-	body := &speedSource{deadline: time.Now().Add(speedWindow), left: speedUpCap}
+	body := &speedSource{deadline: time.Now().Add(window), left: speedUpCap}
 	start := time.Now()
 	resp, err := a.speedRequest(ctx, http.MethodPost, streams+"/up", body)
 	if err != nil {
@@ -78,9 +84,9 @@ func (a *Agent) measureSpeed(ctx context.Context, relay bool) (proto.SysSpeedRes
 	return res, nil
 }
 
-// speedDown reads what the server streams for speedWindow, counted from the
+// speedDown reads what the server streams for the window, counted from the
 // first byte, and returns the rate.
-func (a *Agent) speedDown(ctx context.Context, path string) (float64, error) {
+func (a *Agent) speedDown(ctx context.Context, path string, window time.Duration) (float64, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 	t := time.AfterFunc(speedWait, cancel)
@@ -99,7 +105,7 @@ func (a *Agent) speedDown(ctx context.Context, path string) (float64, error) {
 		k, err := resp.Body.Read(buf)
 		if k > 0 && start.IsZero() {
 			start = time.Now()
-			t.Reset(speedWindow)
+			t.Reset(window)
 		}
 		n += int64(k)
 		if err != nil {