TimingsPlotReporter

lib/timings_plot_reporter.go

@@ -0,0 +1,90 @@
+package vegeta
+
+import (
+	"code.google.com/p/plotinum/plot"
+	"code.google.com/p/plotinum/plotter"
+	"code.google.com/p/plotinum/plotutil"
+	"code.google.com/p/plotinum/vg"
+	"code.google.com/p/plotinum/vg/vgsvg"
+	"container/list"
+	"io"
+	"time"
+)
+
+type TimingsPlotReporter struct {
+	responses *list.List
+}
+
+// NewTimingsPlotReporter initializes a TimingsPlotReporter
+func NewTimingsPlotReporter() *TimingsPlotReporter {
+	return &TimingsPlotReporter{responses: list.New()}
+}
+
+// add inserts response to be used in the report, sorted by timestamp.
+func (r *TimingsPlotReporter) add(res *result) {
+	// Empty list
+	if r.responses.Len() == 0 {
+		r.responses.PushFront(res)
+		return
+	}
+	// Happened after all others
+	if last := r.responses.Back().Value.(*result); last.timestamp.Before(res.timestamp) {
+		r.responses.PushBack(res)
+		return
+	}
+	// Happened before all others
+	if first := r.responses.Front().Value.(*result); first.timestamp.After(res.timestamp) {
+		r.responses.PushFront(res)
+		return
+	}
+	// O(n) worst case insertion time
+	for e := r.responses.Front(); e != nil; e = e.Next() {
+		needle := e.Value.(*result)
+		if res.timestamp.Before(needle.timestamp) {
+			r.responses.InsertBefore(res, e)
+			return
+		}
+	}
+}
+
+// Report builds up a plot of the response times of the requests
+// in SVG format and writes it to out
+func (r *TimingsPlotReporter) Report(out io.Writer) error {
+	timestamps := make([]time.Time, 0)
+	timings := make([]time.Duration, 0)
+
+	for e := r.responses.Front(); e != nil; e = e.Next() {
+		r := e.Value.(*result)
+		timestamps = append(timestamps, r.timestamp)
+		timings = append(timings, r.timing)
+	}
+
+	p, err := plot.New()
+	if err != nil {
+		return err
+	}
+	pts := make(plotter.XYs, len(timestamps))
+	for i := 0; i < len(pts); i++ {
+		pts[i].X = timestamps[i].Sub(timestamps[0]).Seconds()
+		pts[i].Y = timings[i].Seconds()
+	}
+
+	line, err := plotter.NewLine(pts)
+	if err != nil {
+		return err
+	}
+	line.Color = plotutil.Color(1)
+
+	p.Add(line)
+	p.X.Padding = vg.Length(3.0)
+	p.X.Label.Text = "Time elapsed"
+	p.Y.Padding = vg.Length(3.0)
+	p.Y.Label.Text = "Latency (seconds)"
+
+	w, h := vg.Millimeters(float64(len(timestamps))), vg.Centimeters(12.0)
+	canvas := vgsvg.New(w, h)
+	p.Draw(plot.MakeDrawArea(canvas))
+
+	_, err = canvas.WriteTo(out)
+	return err
+}