http2_deadlock.go

package main

import (
	"bytes"
	"crypto/tls"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"sync"
	"time"

	"golang.org/x/net/http2"
)

func main() {
	client := &http.Client{Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}}
	if err := http2.ConfigureTransport(client.Transport.(*http.Transport)); err != nil {
		panic(err)
	}

	cert, _ := tls.X509KeyPair(LocalhostCert, LocalhostKey)
	server := &http.Server{
		Addr:      "0.0.0.0:8080",
		TLSConfig: &tls.Config{Certificates: []tls.Certificate{cert}},
		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.Body != nil {
				defer r.Body.Close()
			}

			switch r.URL.Path {
			case "/1":
				// fmt.Printf("    %s: %v\n", r.URL.Path, r.Header.Get("Content-Length"))
				// make a loopback post request
				post(client, "/2", bytes.NewBufferString("data"))
				// make a loopback post request draining the incoming request's body
				post(client, "/3", r.Body)
			default:
				// fmt.Printf("        %s: %v\n", r.URL.Path, r.Header.Get("Content-Length"))
				data, _ := ioutil.ReadAll(r.Body)
				_ = data
				// fmt.Println("          length", len(data))
			}
		}),
	}

	http2Options := &http2.Server{
	// MaxConcurrentStreams:         250,              // made the default explicit so we can size our buffers
	// MaxUploadBufferPerStream:     256 * 1024,       // shrunk from default 1MB
	// MaxReadFrameSize:             256 * 1024,       // shrunk from default 1MB
	// MaxUploadBufferPerConnection: 256 * 1024 * 250, // grown from default 1MB to handle concurrent streams
	}
	if err := http2.ConfigureServer(server, http2Options); err != nil {
		panic(err)
	}

	go func() {
		fmt.Println(server.ListenAndServeTLS("", ""))
	}()

	// let the server establish
	time.Sleep(time.Second)

	// make a 10MB data block
	data := make([]byte, 10*1024*1024)

	// repeatedly and concurrently post data to /1 using client
	wg := &sync.WaitGroup{}
	wg.Add(200)
	for i := 0; i < 200; i++ {
		go func(i int) {
			fmt.Printf("attempt %d -->\n", i)
			post(client, "/1", bytes.NewReader(data))
			fmt.Printf("attempt %d <--\n", i)
			wg.Done()
		}(i)
	}
	wg.Wait()

	// quit
	server.Close()
}

func post(client *http.Client, path string, body io.Reader) error {
	req, err := http.NewRequest("POST", "https://127.0.0.1:8080"+path, body)
	if err != nil {
		return err
	}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	ioutil.ReadAll(resp.Body)
	resp.Body.Close()
	return nil
}

// LocalhostCert is a PEM-encoded TLS cert with SAN IPs
// "127.0.0.1" and "[::1]", expiring at Jan 29 16:00:00 2084 GMT.
// generated from src/crypto/tls:
// go run generate_cert.go  --rsa-bits 1024 --host 127.0.0.1,::1,example.com --ca --start-date "Jan 1 00:00:00 1970" --duration=1000000h
var LocalhostCert = []byte(`-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`)

// LocalhostKey is the private key for localhostCert.
var LocalhostKey = []byte(`-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----`)