func RandTestBogusPrivateKey() (TestBogusPrivateKey, error) {
r := u.NewTimeSeededRand()
k := make([]byte, 5)
if _, err := io.ReadFull(r, k); err != nil {
return nil, err
}
return TestBogusPrivateKey(k), nil
}
func newSender() (chan sendChans, func(s inet.Stream)) {
scc := make(chan sendChans)
return scc, func(s inet.Stream) {
sc := newSendChans()
scc <- sc
defer func() {
s.Close()
sc.closed <- struct{}{}
}()
buf := make([]byte, 65536)
buf2 := make([]byte, 65536)
u.NewTimeSeededRand().Read(buf)
for {
select {
case <-sc.close_:
return
case <-sc.send:
}
// send a randomly sized subchunk
from := rand.Intn(len(buf) / 2)
to := rand.Intn(len(buf) / 2)
sendbuf := buf[from : from+to]
log.Debugf("sender sending %d bytes", len(sendbuf))
n, err := s.Write(sendbuf)
if err != nil {
log.Debug("sender error. exiting:", err)
return
}
log.Debugf("sender wrote %d bytes", n)
sc.sent <- struct{}{}
if n, err = io.ReadFull(s, buf2[:len(sendbuf)]); err != nil {
log.Debug("sender error. failed to read:", err)
return
}
log.Debugf("sender read %d bytes", n)
sc.read <- struct{}{}
}
}
}
func ping(s inet.Stream) (time.Duration, error) {
buf := make([]byte, PingSize)
u.NewTimeSeededRand().Read(buf)
before := time.Now()
_, err := s.Write(buf)
if err != nil {
return 0, err
}
rbuf := make([]byte, PingSize)
_, err = io.ReadFull(s, rbuf)
if err != nil {
return 0, err
}
if !bytes.Equal(buf, rbuf) {
return 0, errors.New("ping packet was incorrect!")
}
return time.Since(before), nil
}
// TestStBackpressureStreamWrite tests whether streams see proper
// backpressure when writing data over the network streams.
func TestStBackpressureStreamWrite(t *testing.T) {
// senderWrote signals that the sender wrote bytes to remote.
// the value is the count of bytes written.
senderWrote := make(chan int, 10000)
// sender signals it's done (errored out)
senderDone := make(chan struct{})
// writeStats lets us listen to all the writes and return
// how many happened and how much was written
writeStats := func() (int, int) {
writes := 0
bytes := 0
for {
select {
case n := <-senderWrote:
writes++
bytes = bytes + n
default:
log.Debugf("stats: sender wrote %d bytes, %d writes", bytes, writes)
return bytes, writes
}
}
}
// sender attempts to write as fast as possible, signaling on the
// completion of every write. This makes it possible to see how
// fast it's actually writing. We pair this with a receiver
// that waits for a signal to read.
sender := func(s inet.Stream) {
defer func() {
s.Close()
senderDone <- struct{}{}
}()
// ready a buffer of random data
buf := make([]byte, 65536)
u.NewTimeSeededRand().Read(buf)
for {
// send a randomly sized subchunk
from := rand.Intn(len(buf) / 2)
to := rand.Intn(len(buf) / 2)
sendbuf := buf[from : from+to]
n, err := s.Write(sendbuf)
if err != nil {
log.Debug("sender error. exiting:", err)
return
}
log.Debugf("sender wrote %d bytes", n)
senderWrote <- n
}
}
// receive a number of bytes from a stream.
// returns the number of bytes written.
receive := func(s inet.Stream, expect int) {
log.Debugf("receiver to read %d bytes", expect)
rbuf := make([]byte, expect)
n, err := io.ReadFull(s, rbuf)
if err != nil {
t.Error("read failed:", err)
}
if expect != n {
t.Error("read len differs: %d != %d", expect, n)
}
}
// ok let's do it!
// setup the networks
ctx := context.Background()
h1 := testutil.GenHostSwarm(t, ctx)
h2 := testutil.GenHostSwarm(t, ctx)
// setup sender handler on 1
h1.SetStreamHandler(protocol.TestingID, sender)
h2pi := h2.Peerstore().PeerInfo(h2.ID())
log.Debugf("dialing %s", h2pi.Addrs)
if err := h1.Connect(ctx, h2pi); err != nil {
t.Fatalf("Failed to connect:", err)
}
// open a stream, from 2->1, this is our reader
s, err := h2.NewStream(context.Background(), h1.ID(), protocol.TestingID)
if err != nil {
t.Fatal(err)
}
// let's make sure r/w works.
testSenderWrote := func(bytesE int) {
bytesA, writesA := writeStats()
if bytesA != bytesE {
t.Errorf("numbers failed: %d =?= %d bytes, via %d writes", bytesA, bytesE, writesA)
}
}
// trigger lazy connection handshaking
_, err = s.Read(nil)
if err != nil {
t.Fatal(err)
}
// 500ms rounds of lockstep write + drain
roundsStart := time.Now()
roundsTotal := 0
for roundsTotal < (2 << 20) {
// let the sender fill its buffers, it will stop sending.
<-time.After(300 * time.Millisecond)
b, _ := writeStats()
testSenderWrote(0)
testSenderWrote(0)
// drain it all, wait again
receive(s, b)
roundsTotal = roundsTotal + b
}
roundsTime := time.Since(roundsStart)
// now read continously, while we measure stats.
stop := make(chan struct{})
contStart := time.Now()
go func() {
for {
select {
case <-stop:
return
default:
receive(s, 2<<15)
}
}
}()
contTotal := 0
for contTotal < (2 << 20) {
n := <-senderWrote
contTotal += n
}
stop <- struct{}{}
contTime := time.Since(contStart)
// now compare! continuous should've been faster AND larger
if roundsTime < contTime {
t.Error("continuous should have been faster")
}
if roundsTotal < contTotal {
t.Error("continuous should have been larger, too!")
}
// and a couple rounds more for good measure ;)
for i := 0; i < 3; i++ {
// let the sender fill its buffers, it will stop sending.
<-time.After(300 * time.Millisecond)
b, _ := writeStats()
testSenderWrote(0)
testSenderWrote(0)
// drain it all, wait again
receive(s, b)
}
// this doesn't work :(:
// // now for the sugar on top: let's tear down the receiver. it should
// // exit the sender.
// n1.Close()
// testSenderWrote(0)
// testSenderWrote(0)
// select {
// case <-time.After(2 * time.Second):
// t.Error("receiver shutdown failed to exit sender")
// case <-senderDone:
// log.Info("handler backpressure works!")
// }
}
