torrent/rlreader_test.go

129 lines
2.3 KiB
Go

package torrent
import (
"io"
"log"
"math/rand"
"sync"
"testing"
"time"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"golang.org/x/time/rate"
)
func writeN(ws []io.Writer, n int) error {
b := make([]byte, n)
for _, w := range ws[1:] {
n1 := rand.Intn(n)
wn, err := w.Write(b[:n1])
if wn != n1 {
if err == nil {
panic(n1)
}
return err
}
n -= n1
}
wn, err := ws[0].Write(b[:n])
if wn != n {
if err == nil {
panic(n)
}
}
return err
}
func TestRateLimitReaders(t *testing.T) {
const (
numReaders = 2
bytesPerSecond = 100
burst = 5
readSize = 6
writeRounds = 10
bytesPerRound = 12
)
control := rate.NewLimiter(bytesPerSecond, burst)
shared := rate.NewLimiter(bytesPerSecond, burst)
var (
ws []io.Writer
cs []io.Closer
)
wg := sync.WaitGroup{}
type read struct {
N int
// When the read was allowed.
At time.Time
}
reads := make(chan read)
done := make(chan struct{})
for i := 0; i < numReaders; i += 1 {
r, w := io.Pipe()
ws = append(ws, w)
cs = append(cs, w)
wg.Add(1)
go func() {
defer wg.Done()
r := rateLimitedReader{
l: shared,
r: r,
}
b := make([]byte, readSize)
for {
n, err := r.Read(b)
select {
case reads <- read{n, r.lastRead}:
case <-done:
return
}
if err == io.EOF {
return
}
if err != nil {
panic(err)
}
}
}()
}
closeAll := func() {
for _, c := range cs {
c.Close()
}
}
defer func() {
close(done)
closeAll()
wg.Wait()
}()
written := 0
go func() {
for i := 0; i < writeRounds; i += 1 {
err := writeN(ws, bytesPerRound)
if err != nil {
log.Printf("error writing: %s", err)
break
}
written += bytesPerRound
}
closeAll()
wg.Wait()
close(reads)
}()
totalBytesRead := 0
started := time.Now()
for r := range reads {
totalBytesRead += r.N
require.False(t, r.At.IsZero())
// Copy what the reader should have done with its reservation.
res := control.ReserveN(r.At, r.N)
// If we don't have to wait with the control, the reader has gone too
// fast.
if res.Delay() > 0 {
log.Printf("%d bytes not allowed at %s", r.N, time.Since(started))
t.FailNow()
}
}
assert.EqualValues(t, writeRounds*bytesPerRound, totalBytesRead)
}