go timeout_test 源码
golang timeout_test 代码
文件路径：/src/os/timeout_test.go
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !js && !plan9 && !windows
package os_test
import (
"fmt"
"io"
"math/rand"
"os"
"os/signal"
"runtime"
"sync"
"syscall"
"testing"
"time"
)
func TestNonpollableDeadline(t *testing.T) {
// On BSD systems regular files seem to be pollable,
// so just run this test on Linux.
if runtime.GOOS != "linux" {
t.Skipf("skipping on %s", runtime.GOOS)
}
f, err := os.CreateTemp("", "ostest")
if err != nil {
t.Fatal(err)
}
defer os.Remove(f.Name())
defer f.Close()
deadline := time.Now().Add(10 * time.Second)
if err := f.SetDeadline(deadline); err != os.ErrNoDeadline {
t.Errorf("SetDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline)
}
if err := f.SetReadDeadline(deadline); err != os.ErrNoDeadline {
t.Errorf("SetReadDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline)
}
if err := f.SetWriteDeadline(deadline); err != os.ErrNoDeadline {
t.Errorf("SetWriteDeadline on file returned %v, wanted %v", err, os.ErrNoDeadline)
}
}
// noDeadline is a zero time.Time value, which cancels a deadline.
var noDeadline time.Time
var readTimeoutTests = []struct {
timeout time.Duration
xerrs [2]error // expected errors in transition
}{
// Tests that read deadlines work, even if there's data ready
// to be read.
{-5 * time.Second, [2]error{os.ErrDeadlineExceeded, os.ErrDeadlineExceeded}},
{50 * time.Millisecond, [2]error{nil, os.ErrDeadlineExceeded}},
}
// There is a very similar copy of this in net/timeout_test.go.
func TestReadTimeout(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
if _, err := w.Write([]byte("READ TIMEOUT TEST")); err != nil {
t.Fatal(err)
}
for i, tt := range readTimeoutTests {
if err := r.SetReadDeadline(time.Now().Add(tt.timeout)); err != nil {
t.Fatalf("#%d: %v", i, err)
}
var b [1]byte
for j, xerr := range tt.xerrs {
for {
n, err := r.Read(b[:])
if xerr != nil {
if !isDeadlineExceeded(err) {
t.Fatalf("#%d/%d: %v", i, j, err)
}
}
if err == nil {
time.Sleep(tt.timeout / 3)
continue
}
if n != 0 {
t.Fatalf("#%d/%d: read %d; want 0", i, j, n)
}
break
}
}
}
}
// There is a very similar copy of this in net/timeout_test.go.
func TestReadTimeoutMustNotReturn(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
max := time.NewTimer(100 * time.Millisecond)
defer max.Stop()
ch := make(chan error)
go func() {
if err := r.SetDeadline(time.Now().Add(-5 * time.Second)); err != nil {
t.Error(err)
}
if err := r.SetWriteDeadline(time.Now().Add(-5 * time.Second)); err != nil {
t.Error(err)
}
if err := r.SetReadDeadline(noDeadline); err != nil {
t.Error(err)
}
var b [1]byte
_, err := r.Read(b[:])
ch <- err
}()
select {
case err := <-ch:
t.Fatalf("expected Read to not return, but it returned with %v", err)
case <-max.C:
w.Close()
err := <-ch // wait for tester goroutine to stop
if os.IsTimeout(err) {
t.Fatal(err)
}
}
}
var writeTimeoutTests = []struct {
timeout time.Duration
xerrs [2]error // expected errors in transition
}{
// Tests that write deadlines work, even if there's buffer
// space available to write.
{-5 * time.Second, [2]error{os.ErrDeadlineExceeded, os.ErrDeadlineExceeded}},
{10 * time.Millisecond, [2]error{nil, os.ErrDeadlineExceeded}},
}
// There is a very similar copy of this in net/timeout_test.go.
func TestWriteTimeout(t *testing.T) {
t.Parallel()
for i, tt := range writeTimeoutTests {
t.Run(fmt.Sprintf("#%d", i), func(t *testing.T) {
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
if err := w.SetWriteDeadline(time.Now().Add(tt.timeout)); err != nil {
t.Fatalf("%v", err)
}
for j, xerr := range tt.xerrs {
for {
n, err := w.Write([]byte("WRITE TIMEOUT TEST"))
if xerr != nil {
if !isDeadlineExceeded(err) {
t.Fatalf("%d: %v", j, err)
}
}
if err == nil {
time.Sleep(tt.timeout / 3)
continue
}
if n != 0 {
t.Fatalf("%d: wrote %d; want 0", j, n)
}
break
}
}
})
}
}
// There is a very similar copy of this in net/timeout_test.go.
func TestWriteTimeoutMustNotReturn(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
max := time.NewTimer(100 * time.Millisecond)
defer max.Stop()
ch := make(chan error)
go func() {
if err := w.SetDeadline(time.Now().Add(-5 * time.Second)); err != nil {
t.Error(err)
}
if err := w.SetReadDeadline(time.Now().Add(-5 * time.Second)); err != nil {
t.Error(err)
}
if err := w.SetWriteDeadline(noDeadline); err != nil {
t.Error(err)
}
var b [1]byte
for {
if _, err := w.Write(b[:]); err != nil {
ch <- err
break
}
}
}()
select {
case err := <-ch:
t.Fatalf("expected Write to not return, but it returned with %v", err)
case <-max.C:
r.Close()
err := <-ch // wait for tester goroutine to stop
if os.IsTimeout(err) {
t.Fatal(err)
}
}
}
const (
// minDynamicTimeout is the minimum timeout to attempt for
// tests that automatically increase timeouts until success.
//
// Lower values may allow tests to succeed more quickly if the value is close
// to the true minimum, but may require more iterations (and waste more time
// and CPU power on failed attempts) if the timeout is too low.
minDynamicTimeout = 1 * time.Millisecond
// maxDynamicTimeout is the maximum timeout to attempt for
// tests that automatically increase timeouts until succeess.
//
// This should be a strict upper bound on the latency required to hit a
// timeout accurately, even on a slow or heavily-loaded machine. If a test
// would increase the timeout beyond this value, the test fails.
maxDynamicTimeout = 4 * time.Second
)
// timeoutUpperBound returns the maximum time that we expect a timeout of
// duration d to take to return the caller.
func timeoutUpperBound(d time.Duration) time.Duration {
switch runtime.GOOS {
case "openbsd", "netbsd":
// NetBSD and OpenBSD seem to be unable to reliably hit deadlines even when
// the absolute durations are long.
// In https://build.golang.org/log/c34f8685d020b98377dd4988cd38f0c5bd72267e,
// we observed that an openbsd-amd64-68 builder took 4.090948779s for a
// 2.983020682s timeout (37.1% overhead).
// (See https://go.dev/issue/50189 for further detail.)
// Give them lots of slop to compensate.
return d * 3 / 2
}
// Other platforms seem to hit their deadlines more reliably,
// at least when they are long enough to cover scheduling jitter.
return d * 11 / 10
}
// nextTimeout returns the next timeout to try after an operation took the given
// actual duration with a timeout shorter than that duration.
func nextTimeout(actual time.Duration) (next time.Duration, ok bool) {
if actual >= maxDynamicTimeout {
return maxDynamicTimeout, false
}
// Since the previous attempt took actual, we can't expect to beat that
// duration by any significant margin. Try the next attempt with an arbitrary
// factor above that, so that our growth curve is at least exponential.
next = actual * 5 / 4
if next > maxDynamicTimeout {
return maxDynamicTimeout, true
}
return next, true
}
// There is a very similar copy of this in net/timeout_test.go.
func TestReadTimeoutFluctuation(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
d := minDynamicTimeout
b := make([]byte, 256)
for {
t.Logf("SetReadDeadline(+%v)", d)
t0 := time.Now()
deadline := t0.Add(d)
if err = r.SetReadDeadline(deadline); err != nil {
t.Fatalf("SetReadDeadline(%v): %v", deadline, err)
}
var n int
n, err = r.Read(b)
t1 := time.Now()
if n != 0 || err == nil || !isDeadlineExceeded(err) {
t.Errorf("Read did not return (0, timeout): (%d, %v)", n, err)
}
actual := t1.Sub(t0)
if t1.Before(deadline) {
t.Errorf("Read took %s; expected at least %s", actual, d)
}
if t.Failed() {
return
}
if want := timeoutUpperBound(d); actual > want {
next, ok := nextTimeout(actual)
if !ok {
t.Fatalf("Read took %s; expected at most %v", actual, want)
}
// Maybe this machine is too slow to reliably schedule goroutines within
// the requested duration. Increase the timeout and try again.
t.Logf("Read took %s (expected %s); trying with longer timeout", actual, d)
d = next
continue
}
break
}
}
// There is a very similar copy of this in net/timeout_test.go.
func TestWriteTimeoutFluctuation(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
d := minDynamicTimeout
for {
t.Logf("SetWriteDeadline(+%v)", d)
t0 := time.Now()
deadline := t0.Add(d)
if err = w.SetWriteDeadline(deadline); err != nil {
t.Fatalf("SetWriteDeadline(%v): %v", deadline, err)
}
var n int64
for {
var dn int
dn, err = w.Write([]byte("TIMEOUT TRANSMITTER"))
n += int64(dn)
if err != nil {
break
}
}
t1 := time.Now()
if err == nil || !isDeadlineExceeded(err) {
t.Fatalf("Write did not return (any, timeout): (%d, %v)", n, err)
}
actual := t1.Sub(t0)
if t1.Before(deadline) {
t.Errorf("Write took %s; expected at least %s", actual, d)
}
if t.Failed() {
return
}
if want := timeoutUpperBound(d); actual > want {
if n > 0 {
// SetWriteDeadline specifies a time “after which I/O operations fail
// instead of blocking”. However, the kernel's send buffer is not yet
// full, we may be able to write some arbitrary (but finite) number of
// bytes to it without blocking.
t.Logf("Wrote %d bytes into send buffer; retrying until buffer is full", n)
if d <= maxDynamicTimeout/2 {
// We don't know how long the actual write loop would have taken if
// the buffer were full, so just guess and double the duration so that
// the next attempt can make twice as much progress toward filling it.
d *= 2
}
} else if next, ok := nextTimeout(actual); !ok {
t.Fatalf("Write took %s; expected at most %s", actual, want)
} else {
// Maybe this machine is too slow to reliably schedule goroutines within
// the requested duration. Increase the timeout and try again.
t.Logf("Write took %s (expected %s); trying with longer timeout", actual, d)
d = next
}
continue
}
break
}
}
// There is a very similar copy of this in net/timeout_test.go.
func TestVariousDeadlines(t *testing.T) {
t.Parallel()
testVariousDeadlines(t)
}
// There is a very similar copy of this in net/timeout_test.go.
func TestVariousDeadlines1Proc(t *testing.T) {
// Cannot use t.Parallel - modifies global GOMAXPROCS.
if testing.Short() {
t.Skip("skipping in short mode")
}
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1))
testVariousDeadlines(t)
}
// There is a very similar copy of this in net/timeout_test.go.
func TestVariousDeadlines4Proc(t *testing.T) {
// Cannot use t.Parallel - modifies global GOMAXPROCS.
if testing.Short() {
t.Skip("skipping in short mode")
}
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
testVariousDeadlines(t)
}
type neverEnding byte
func (b neverEnding) Read(p []byte) (int, error) {
for i := range p {
p[i] = byte(b)
}
return len(p), nil
}
func testVariousDeadlines(t *testing.T) {
type result struct {
n int64
err error
d time.Duration
}
handler := func(w *os.File, pasvch chan result) {
// The writer, with no timeouts of its own,
// sending bytes to clients as fast as it can.
t0 := time.Now()
n, err := io.Copy(w, neverEnding('a'))
dt := time.Since(t0)
pasvch <- result{n, err, dt}
}
for _, timeout := range []time.Duration{
1 * time.Nanosecond,
2 * time.Nanosecond,
5 * time.Nanosecond,
50 * time.Nanosecond,
100 * time.Nanosecond,
200 * time.Nanosecond,
500 * time.Nanosecond,
750 * time.Nanosecond,
1 * time.Microsecond,
5 * time.Microsecond,
25 * time.Microsecond,
250 * time.Microsecond,
500 * time.Microsecond,
1 * time.Millisecond,
5 * time.Millisecond,
100 * time.Millisecond,
250 * time.Millisecond,
500 * time.Millisecond,
1 * time.Second,
} {
numRuns := 3
if testing.Short() {
numRuns = 1
if timeout > 500*time.Microsecond {
continue
}
}
for run := 0; run < numRuns; run++ {
t.Run(fmt.Sprintf("%v-%d", timeout, run+1), func(t *testing.T) {
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
pasvch := make(chan result)
go handler(w, pasvch)
tooLong := 5 * time.Second
max := time.NewTimer(tooLong)
defer max.Stop()
actvch := make(chan result)
go func() {
t0 := time.Now()
if err := r.SetDeadline(t0.Add(timeout)); err != nil {
t.Error(err)
}
n, err := io.Copy(io.Discard, r)
dt := time.Since(t0)
r.Close()
actvch <- result{n, err, dt}
}()
select {
case res := <-actvch:
if !isDeadlineExceeded(err) {
t.Logf("good client timeout after %v, reading %d bytes", res.d, res.n)
} else {
t.Fatalf("client Copy = %d, %v; want timeout", res.n, res.err)
}
case <-max.C:
t.Fatalf("timeout (%v) waiting for client to timeout (%v) reading", tooLong, timeout)
}
select {
case res := <-pasvch:
t.Logf("writer in %v wrote %d: %v", res.d, res.n, res.err)
case <-max.C:
t.Fatalf("timeout waiting for writer to finish writing")
}
})
}
}
}
// There is a very similar copy of this in net/timeout_test.go.
func TestReadWriteDeadlineRace(t *testing.T) {
t.Parallel()
N := 1000
if testing.Short() {
N = 50
}
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
var wg sync.WaitGroup
wg.Add(3)
go func() {
defer wg.Done()
tic := time.NewTicker(2 * time.Microsecond)
defer tic.Stop()
for i := 0; i < N; i++ {
if err := r.SetReadDeadline(time.Now().Add(2 * time.Microsecond)); err != nil {
break
}
if err := w.SetWriteDeadline(time.Now().Add(2 * time.Microsecond)); err != nil {
break
}
<-tic.C
}
}()
go func() {
defer wg.Done()
var b [1]byte
for i := 0; i < N; i++ {
_, err := r.Read(b[:])
if err != nil && !isDeadlineExceeded(err) {
t.Error("Read returned non-timeout error", err)
}
}
}()
go func() {
defer wg.Done()
var b [1]byte
for i := 0; i < N; i++ {
_, err := w.Write(b[:])
if err != nil && !isDeadlineExceeded(err) {
t.Error("Write returned non-timeout error", err)
}
}
}()
wg.Wait() // wait for tester goroutine to stop
}
// TestRacyRead tests that it is safe to mutate the input Read buffer
// immediately after cancellation has occurred.
func TestRacyRead(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
var wg sync.WaitGroup
defer wg.Wait()
go io.Copy(w, rand.New(rand.NewSource(0)))
r.SetReadDeadline(time.Now().Add(time.Millisecond))
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
b1 := make([]byte, 1024)
b2 := make([]byte, 1024)
for j := 0; j < 100; j++ {
_, err := r.Read(b1)
copy(b1, b2) // Mutate b1 to trigger potential race
if err != nil {
if !isDeadlineExceeded(err) {
t.Error(err)
}
r.SetReadDeadline(time.Now().Add(time.Millisecond))
}
}
}()
}
}
// TestRacyWrite tests that it is safe to mutate the input Write buffer
// immediately after cancellation has occurred.
func TestRacyWrite(t *testing.T) {
t.Parallel()
r, w, err := os.Pipe()
if err != nil {
t.Fatal(err)
}
defer r.Close()
defer w.Close()
var wg sync.WaitGroup
defer wg.Wait()
go io.Copy(io.Discard, r)
w.SetWriteDeadline(time.Now().Add(time.Millisecond))
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
b1 := make([]byte, 1024)
b2 := make([]byte, 1024)
for j := 0; j < 100; j++ {
_, err := w.Write(b1)
copy(b1, b2) // Mutate b1 to trigger potential race
if err != nil {
if !isDeadlineExceeded(err) {
t.Error(err)
}
w.SetWriteDeadline(time.Now().Add(time.Millisecond))
}
}
}()
}
}
// Closing a TTY while reading from it should not hang. Issue 23943.
func TestTTYClose(t *testing.T) {
// Ignore SIGTTIN in case we are running in the background.
signal.Ignore(syscall.SIGTTIN)
defer signal.Reset(syscall.SIGTTIN)
f, err := os.Open("/dev/tty")
if err != nil {
t.Skipf("skipping because opening /dev/tty failed: %v", err)
}
go func() {
var buf [1]byte
f.Read(buf[:])
}()
// Give the goroutine a chance to enter the read.
// It doesn't matter much if it occasionally fails to do so,
// we won't be testing what we want to test but the test will pass.
time.Sleep(time.Millisecond)
c := make(chan bool)
go func() {
defer close(c)
f.Close()
}()
select {
case <-c:
case <-time.After(time.Second):
t.Error("timed out waiting for close")
}
// On some systems the goroutines may now be hanging.
// There's not much we can do about that.
}
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