plotting: make it possible to create CSV files

.vscode/dict.txt

@@ -71,3 +71,6 @@ unittests
 unmarshals
 wcfg
 wrfs
+xlabel
+xyer
+ylabel

metrics/plotting/clientlatency.go

@@ -2,6 +2,7 @@ package plotting
 
 import (
 	"fmt"
+	"path"
 	"time"
 
 	"github.com/relab/hotstuff/metrics/types"
@@ -43,7 +44,16 @@ func (p *ClientLatencyPlot) Add(measurement interface{}) {
 
 // PlotAverage plots the average latency of all clients within each measurement interval.
 func (p *ClientLatencyPlot) PlotAverage(filename string, measurementInterval time.Duration) (err error) {
-	return GonumPlot(filename, "Time (seconds)", "Latency (ms)", func(plt *plot.Plot) error {
+	const (
+		xlabel = "Time (seconds)"
+		ylabel = "Latency (ms)"
+	)
+	if path.Ext(filename) == ".csv" {
+		return CSVPlot(filename, []string{xlabel, ylabel}, func() plotter.XYer {
+			return avgLatency(p, measurementInterval)
+		})
+	}
+	return GonumPlot(filename, xlabel, ylabel, func(plt *plot.Plot) error {
 		// TODO: error bars
 		if err := plotutil.AddLinePoints(plt, avgLatency(p, measurementInterval)); err != nil {
 			return fmt.Errorf("failed to add line plot: %w", err)

metrics/plotting/helper.go

@@ -1,8 +1,10 @@
 package plotting
 
 import (
+	"encoding/csv"
 	"fmt"
 	"image/color"
+	"os"
 	"time"
 
 	"github.com/relab/hotstuff/metrics/types"
@@ -165,3 +167,26 @@ func (xy xyer) XY(i int) (x float64, y float64) {
 	p := xy[i]
 	return p.x, p.y
 }
+
+// CSVPlot writes to a CSV file.
+func CSVPlot(filename string, headers []string, plot func() plotter.XYer) error {
+	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	wr := csv.NewWriter(f)
+	err = wr.Write(headers)
+	if err != nil {
+		return err
+	}
+	xyer := plot()
+	for i := 0; i < xyer.Len(); i++ {
+		x, y := xyer.XY(i)
+		err = wr.Write([]string{fmt.Sprint(x), fmt.Sprint(y)})
+		if err != nil {
+			return err
+		}
+	}
+	wr.Flush()
+	return f.Close()
+}

metrics/plotting/throughput.go

@@ -2,6 +2,7 @@ package plotting
 
 import (
 	"fmt"
+	"path"
 	"time"
 
 	"github.com/relab/hotstuff/metrics/types"
@@ -44,7 +45,16 @@ func (p *ThroughputPlot) Add(measurement interface{}) {
 
 // PlotAverage plots the average throughput of all replicas at specified time intervals.
 func (p *ThroughputPlot) PlotAverage(filename string, measurementInterval time.Duration) (err error) {
-	return GonumPlot(filename, "Time (seconds)", "Throughput (commands/second)", func(plt *plot.Plot) error {
+	const (
+		xlabel = "Time (seconds)"
+		ylabel = "Throughput (commands/second)"
+	)
+	if path.Ext(filename) == ".csv" {
+		return CSVPlot(filename, []string{xlabel, ylabel}, func() plotter.XYer {
+			return avgThroughput(p, measurementInterval)
+		})
+	}
+	return GonumPlot(filename, xlabel, ylabel, func(plt *plot.Plot) error {
 		if err := plotutil.AddLinePoints(plt, avgThroughput(p, measurementInterval)); err != nil {
 			return fmt.Errorf("failed to add line plot: %w", err)
 		}

metrics/plotting/throughputvslatency.go

@@ -2,6 +2,7 @@ package plotting
 
 import (
 	"fmt"
+	"path"
 	"time"
 
 	"github.com/relab/hotstuff/metrics/types"
@@ -53,7 +54,16 @@ func (p *ThroughputVSLatencyPlot) Add(measurement interface{}) {
 
 // PlotAverage plots the average throughput of all replicas at specified time intervals.
 func (p *ThroughputVSLatencyPlot) PlotAverage(filename string, measurementInterval time.Duration) (err error) {
-	return GonumPlot(filename, "Throughput (commands/second)", "Latency (ms)", func(plt *plot.Plot) error {
+	const (
+		xlabel = "Throughput (commands/second)"
+		ylabel = "Latency (ms)"
+	)
+	if path.Ext(filename) == ".csv" {
+		return CSVPlot(filename, []string{xlabel, ylabel}, func() plotter.XYer {
+			return avgThroughputVSAvgLatency(p, measurementInterval)
+		})
+	}
+	return GonumPlot(filename, xlabel, ylabel, func(plt *plot.Plot) error {
 		if err := plotutil.AddScatters(plt, avgThroughputVSAvgLatency(p, measurementInterval)); err != nil {
 			return fmt.Errorf("failed to add scatter plot: %w", err)
 		}