feat(csv): change to csv from jsonl

internal/qol/measurement.go

@@ -75,7 +75,7 @@ func (r *MeasurementRunner) runMeasurement(upstream string, domains []string, qT
 	defer dnsClient.Close()
 
 	// Setup output files
-	jsonPath, pcapPath := GenerateOutputPaths(r.config.OutputDir, upstream, r.config.DNSSEC, r.config.KeepAlive)
+	csvPath, pcapPath := GenerateOutputPaths(r.config.OutputDir, upstream, r.config.DNSSEC, r.config.KeepAlive)
 
 	keepAliveStr := ""
 	if r.config.KeepAlive {
@@ -83,7 +83,7 @@ func (r *MeasurementRunner) runMeasurement(upstream string, domains []string, qT
 	}
 
 	fmt.Printf(">>> Measuring %s (dnssec=%v%s) → %s\n", upstream, r.config.DNSSEC, keepAliveStr,
-		strings.TrimSuffix(strings.TrimSuffix(jsonPath, ".jsonl"), r.config.OutputDir+"/"))
+		strings.TrimSuffix(strings.TrimSuffix(csvPath, ".csv"), r.config.OutputDir+"/"))
 
 	// Setup packet capture
 	packetCapture, err := capture.NewPacketCapture(r.config.Interface, pcapPath)
@@ -93,7 +93,7 @@ func (r *MeasurementRunner) runMeasurement(upstream string, domains []string, qT
 	defer packetCapture.Close()
 
 	// Setup results writer
-	writer, err := results.NewMetricsWriter(jsonPath)
+	writer, err := results.NewMetricsWriter(csvPath)
 	if err != nil {
 		return err
 	}

internal/qol/results/writer.go

@@ -1,9 +1,10 @@
 package results
 
 import (
-	"encoding/json"
+	"encoding/csv"
 	"fmt"
 	"os"
+	"strconv"
 	"time"
 )
 
@@ -23,29 +24,69 @@ type DNSMetric struct {
 	Error        string    `json:"error,omitempty"`
 }
 
-// Rest stays exactly the same
 type MetricsWriter struct {
-	encoder *json.Encoder
-	file    *os.File
+	writer *csv.Writer
+	file   *os.File
 }
 
 func NewMetricsWriter(path string) (*MetricsWriter, error) {
 	file, err := os.Create(path)
 	if err != nil {
-		return nil, fmt.Errorf("create json output: %w", err)
+		return nil, fmt.Errorf("create csv output: %w", err)
 	}
 
+	writer := csv.NewWriter(file)
+
+	// Write CSV header
+	header := []string{
+		"domain", "query_type", "protocol", "dnssec", "keep_alive",
+		"dns_server", "timestamp", "duration_ns", "duration_ms",
+		"request_size_bytes", "response_size_bytes", "response_code", "error",
+	}
+
+	if err := writer.Write(header); err != nil {
+		file.Close()
+		return nil, fmt.Errorf("write csv header: %w", err)
+	}
+
+	writer.Flush()
+
 	return &MetricsWriter{
-		encoder: json.NewEncoder(file),
-		file:    file,
+		writer: writer,
+		file:   file,
 	}, nil
 }
 
 func (mw *MetricsWriter) WriteMetric(metric DNSMetric) error {
-	return mw.encoder.Encode(metric)
+	record := []string{
+		metric.Domain,
+		metric.QueryType,
+		metric.Protocol,
+		strconv.FormatBool(metric.DNSSEC),
+		strconv.FormatBool(metric.KeepAlive),
+		metric.DNSServer,
+		metric.Timestamp.Format(time.RFC3339),
+		strconv.FormatInt(metric.Duration, 10),
+		strconv.FormatFloat(metric.DurationMs, 'f', 3, 64),
+		strconv.Itoa(metric.RequestSize),
+		strconv.Itoa(metric.ResponseSize),
+		metric.ResponseCode,
+		metric.Error,
+	}
+
+	err := mw.writer.Write(record)
+	if err != nil {
+		return err
+	}
+
+	mw.writer.Flush()
+	return mw.writer.Error()
 }
 
 func (mw *MetricsWriter) Close() error {
+	if mw.writer != nil {
+		mw.writer.Flush()
+	}
 	if mw.file != nil {
 		return mw.file.Close()
 	}

internal/qol/utils.go

@@ -8,7 +8,7 @@ import (
 	"time"
 )
 
-func GenerateOutputPaths(outputDir, upstream string, dnssec, keepAlive bool) (jsonPath, pcapPath string) {
+func GenerateOutputPaths(outputDir, upstream string, dnssec, keepAlive bool) (csvPath, pcapPath string) {
 	proto := DetectProtocol(upstream)
 	serverName := ExtractServerName(upstream)
 	ts := time.Now().Format("20060102_1504")
@@ -18,8 +18,8 @@ func GenerateOutputPaths(outputDir, upstream string, dnssec, keepAlive bool) (js
 	base := fmt.Sprintf("%s_%s_dnssec_%s_keepalive_%s_%s",
 		proto, sanitize(serverName), dnssecStr, keepAliveStr, ts)
 
-	return filepath.Join(outputDir, base+".jsonl"),
-		filepath.Join(outputDir, base+".pcap")
+	return filepath.Join(outputDir, base+".csv"),
+		   filepath.Join(outputDir, base+".pcap")
 }
 
 func sanitize(s string) string {