// This test is a copy&paste of `TestRmTouch` but swapping the rm, for truncation
func TestMvTouch(t *testing.T) {
require := require.New(t)
assert := assert.New(t)
withTempFile(t, time.Millisecond*200, func(t *testing.T, filename string, file *os.File) error {
follow, err := tailer.NewFile(filename)
require.NoError(err, "Failed to create tailer.File")
want := make([]byte, 100)
for i := 0; i < 100; i++ {
want[i] = byte(i)
}
t.Log("Want:", want)
go func() {
max := len(want)
step := max / 10
for i := 0; i < max; i += step {
if i == max/2 {
// CHANGES FROM `TestRmTouch` START HERE
t.Log("Moving the old file out of the way", file)
require.NoError(os.Rename(filename, filename+".old"), "Unable to rename the file")
file, err = os.Create(filename)
require.NoError(err, "failed to create new test file: %v", err)
t.Log("File created again", file)
// CHANGES FROM `TestRmTouch` STOP HERE
}
block := want[i : i+step]
t.Logf("Writing block{%v} to file(%v)\n", block, file)
file.Write(block)
file.Sync()
time.Sleep(time.Millisecond * time.Duration(step))
}
t.Log("Finished writing out all the bytes")
}()
got := make([]byte, len(want))
_, err = io.ReadAtLeast(follow, got, 51)
assert.NoError(err)
t.Log("Got:", got)
return nil
})
}
// This test is a copy&paste of `TestRmTouch` but swapping the rm, for truncation
func TestTruncation(t *testing.T) {
require := require.New(t)
assert := assert.New(t)
withTempFile(t, time.Millisecond*200, func(t *testing.T, filename string, file *os.File) error {
follow, err := tailer.NewFile(filename)
require.NoError(err, "Failed to create tailer.File")
want := make([]byte, 100)
for i := 0; i < 100; i++ {
want[i] = byte(i)
}
t.Log("Want:", want)
go func() {
max := len(want)
step := max / 10
for i := 0; i < max; i += step {
if i == max/2 {
// CHANGES FROM `TestRmTouch` START HERE
t.Log("truncating the file")
file, err := os.OpenFile(filename, os.O_TRUNC, os.ModeTemporary)
require.NoError(err, "unable to truncate file: %v", err)
require.NoError(file.Close(), "failed to close the truncated file")
t.Log("file truncated:", file)
// CHANGES FROM `TestRmTouch` STOP HERE
}
block := want[i : i+step]
t.Logf("Writing block{%v} to file(%v)\n", block, file)
file.Write(block)
file.Sync()
time.Sleep(time.Millisecond * time.Duration(step))
}
t.Log("Finished writing out all the bytes")
}()
got := make([]byte, len(want))
_, err = io.ReadAtLeast(follow, got, 51)
assert.NoError(err)
t.Log("Got:", got)
return nil
})
}
// Run for 50ms constantly trying to read from something that has nothing to read
// This is pretty much here to make sure we don't let our Reader "spin" i.e. return (0, nil)
func TestSpinningReader(t *testing.T) {
require := require.New(t)
assert := assert.New(t)
withTempFile(t, time.Millisecond*150, func(t *testing.T, filename string, file *os.File) error {
tail, err := tailer.NewFile(filename)
require.NoError(err, "Failed to create tailer.File")
// Touch the file repeatedly
go func() {
for _ = range time.Tick(time.Millisecond * 5) {
t.Log("Touching the file")
os.Chtimes(filename, time.Now(), time.Now())
}
}()
// Read from the file as quickly as possible
var readCount int
go func() {
buf := make([]byte, 1000)
for stop := time.After(time.Millisecond * 50); ; {
select {
case <-stop:
return
default:
t.Log("Read called")
_, err := tail.Read(buf)
assert.NoError(err, "read error: %v", err)
t.Log("Read completed")
readCount++
if readCount > 5 {
assert.Fail("Spinning on read")
}
}
}
}()
// This sleep & the go func() of the code above is there because Read should deadlock the thread it is running in
time.Sleep(time.Millisecond * 50)
t.Logf("Reader read '%v' times", readCount)
return nil
})
}
// Can we do the most basic thing, can we follow writes to the file overtime
func TestCanFollowFile(t *testing.T) {
require := require.New(t)
assert := assert.New(t)
withTempFile(t, time.Millisecond*200, func(t *testing.T, filename string, file *os.File) error {
tail, err := tailer.NewFile(filename)
require.NoError(err, "Failed to create tailer.File")
go func() {
for i := 0; i < 10; i++ {
t.Logf("Writing: %v", i)
file.Write([]byte{byte(i)})
time.Sleep(time.Millisecond * 10)
}
}()
t.Log("Preparing to read 10 bytes")
_, err = io.ReadAtLeast(tail, make([]byte, 10), 10)
t.Log("Read 10 bytes, err ->", err)
assert.NoError(err, "Read shouldn't return an error here")
return err
})
}
// Make sure this adheres to a io.ReadCloser & check that reads after closes return (0, io.EOF)
func TestBasicImpl(t *testing.T) {
require := require.New(t)
assert := assert.New(t)
var (
tail io.ReadCloser
n int
err error
)
withTempFile(t, time.Millisecond*150, func(t *testing.T, filename string, file *os.File) error {
tail, err = tailer.NewFile(filename)
require.NoError(err, "Failed to create tailer.File")
err = tail.Close()
require.NoError(err, "Failed to close tailer.File")
n, err = tail.Read(make([]byte, 1))
assert.Equal(0, n, "Calls to Read after Close is called should return 0 bytes read")
assert.Equal(io.EOF, err, "Calls to Read after Close is called should return io.EOF as their error")
return nil
})
}