export qlog files if the QLOGDIR env is set in interop client and server

interop/client/main.go

@@ -13,6 +13,7 @@ import (
 
 	"golang.org/x/sync/errgroup"
 
+	"github.com/lucas-clemente/quic-go"
 	"github.com/lucas-clemente/quic-go/http3"
 	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/interop/http09"
@@ -60,9 +61,18 @@ func runTestcase(testcase string) error {
 	flag.Parse()
 	urls := flag.Args()
 
+	getLogWriter, err := utils.GetQLOGWriter()
+	if err != nil {
+		return err
+	}
+	quicConf := &quic.Config{GetLogWriter: getLogWriter}
+
 	switch testcase {
 	case "http3":
-		r := &http3.RoundTripper{TLSClientConfig: tlsConf}
+		r := &http3.RoundTripper{
+			TLSClientConfig: tlsConf,
+			QuicConfig:      quicConf,
+		}
 		defer r.Close()
 		return downloadFiles(r, urls)
 	case "handshake", "transfer", "retry":
@@ -76,7 +86,10 @@ func runTestcase(testcase string) error {
 		return errUnsupported
 	}
 
-	r := &http09.RoundTripper{TLSClientConfig: tlsConf}
+	r := &http09.RoundTripper{
+		TLSClientConfig: tlsConf,
+		QuicConfig:      quicConf,
+	}
 	defer r.Close()
 	return downloadFiles(r, urls)
 }

interop/server/main.go

@@ -37,9 +37,15 @@ func main() {
 
 	testcase := os.Getenv("TESTCASE")
 
+	getLogWriter, err := utils.GetQLOGWriter()
+	if err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
 	// a quic.Config that doesn't do a Retry
 	quicConf := &quic.Config{
-		AcceptToken: func(_ net.Addr, _ *quic.Token) bool { return true },
+		AcceptToken:  func(_ net.Addr, _ *quic.Token) bool { return true },
+		GetLogWriter: getLogWriter,
 	}
 	tlsConf = testdata.GetTLSConfig()
 	tlsConf.KeyLogWriter = keyLog

interop/utils/logging.go

@@ -1,8 +1,11 @@
 package utils
 
 import (
+	"fmt"
 	"io"
+	"log"
 	"os"
+	"strings"
 )
 
 // GetSSLKeyLog creates a file for the TLS key log
@@ -17,3 +20,24 @@ func GetSSLKeyLog() (io.WriteCloser, error) {
 	}
 	return f, nil
 }
+
+// GetQLOGWriter creates the QLOGDIR and returns the GetLogWriter callback
+func GetQLOGWriter() (func(connID []byte) io.WriteCloser, error) {
+	qlogDir := os.Getenv("QLOGDIR")
+	if len(qlogDir) == 0 {
+		return nil, nil
+	}
+	if _, err := os.Stat(qlogDir); os.IsNotExist(err) {
+		if err := os.MkdirAll(qlogDir, 0666); err != nil {
+			return nil, fmt.Errorf("failed to create qlog dir %s: %s", qlogDir, err.Error())
+		}
+	}
+	return func(connID []byte) io.WriteCloser {
+		path := fmt.Sprintf("%s/%x.qlog", strings.TrimRight(qlogDir, "/"), connID)
+		f, err := os.Create(path)
+		if err != nil {
+			log.Fatalf("Failed to create qlog file %s: %s", path, err.Error())
+		}
+		return f
+	}, nil
+}