add a client and server implementation for the interop test runner

interop/client/main.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/lucas-clemente/quic-go/http3"
+	"github.com/lucas-clemente/quic-go/interop/http09"
+	"golang.org/x/sync/errgroup"
+)
+
+func main() {
+	logFile, err := os.Create("/logs/log.txt")
+	if err != nil {
+		fmt.Printf("Could not create log file: %s\n", err.Error())
+		os.Exit(1)
+	}
+	defer logFile.Close()
+	log.SetOutput(logFile)
+
+	flag.Parse()
+	urls := flag.Args()
+
+	testcase := os.Getenv("TESTCASE")
+
+	var useH3 bool
+	switch testcase {
+	case "handshake", "transfer", "retry":
+	case "http3":
+		useH3 = true
+	default:
+		fmt.Printf("unsupported test case: %s\n", testcase)
+		os.Exit(127)
+	}
+
+	var roundTripper http.RoundTripper
+	if useH3 {
+		r := &http3.RoundTripper{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}
+		defer r.Close()
+		roundTripper = r
+	} else {
+		r := &http09.RoundTripper{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}
+		defer r.Close()
+		roundTripper = r
+	}
+
+	var g errgroup.Group
+	for _, u := range urls {
+		url := u
+		g.Go(func() error {
+			return downloadFile(roundTripper, url)
+		})
+	}
+	if err := g.Wait(); err != nil {
+		fmt.Printf("Downloading files failed: %s\n", err.Error())
+		os.Exit(1)
+	}
+}
+
+func downloadFile(cl http.RoundTripper, url string) error {
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	rsp, err := cl.RoundTrip(req)
+	if err != nil {
+		return err
+	}
+	defer rsp.Body.Close()
+
+	file, err := os.Create("/downloads" + req.URL.Path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	_, err = io.Copy(file, rsp.Body)
+	return err
+}