Please take a look.


https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go
File utils/tailer/tailer.go (right):

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode41
utils/tailer/tailer.go:41: // Writer. The reading beginns the specified
number of matching lines
On 2013/12/10 15:14:25, rog wrote:
> s/beginns/begins/

Done.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode43
utils/tailer/tailer.go:43: func NewStandardTailer(readSeeker
io.ReadSeeker, writer io.Writer, lines int, filter TailerFilterFunc)
*Tailer {
On 2013/12/10 15:14:25, rog wrote:
> Given that this function is going to be the one that everyone calls, I
think I'd
> name it NewTailer, but do we actually need to expose buffer size and
poll
> interval publicly except to the tailer tests?

Done.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode126
utils/tailer/tailer.go:126: readBuffer := make([]byte, t.bufsize)
On 2013/12/10 15:14:25, rog wrote:
> This seems rather complex to me - I don't fully trust myself to vet
the logic.

Used it, even if I have the same troubles following your array logic and
the needed debugging. Thankfully the comments helped to follow the idea.
And at least it has less lines. ;) Thx.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode198
utils/tailer/tailer.go:198: // Reached beginnig of data.
On 2013/12/10 15:14:25, rog wrote:
> s/beginnig/beginning/

Not needed anymore due to new function.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode212
utils/tailer/tailer.go:212: buffer, err := t.reader.ReadBytes(delimiter)
On 2013/12/10 15:14:25, rog wrote:
> ReadBytes can't return ErrBufferFull.

> I think you want to use ReadSlice.
> Also, if the first call succeeds, we should just return the slice that
we got
> from ReadSlice - that way in the usual case that the line is shorter
than the
> bufio buffer we can avoid any allocation.

Done.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode226
utils/tailer/tailer.go:226: if len(line) == 0 || line[len(line)-1] ==
delimiter {
On 2013/12/10 15:14:25, rog wrote:
> This can't happen. (from the docs: "returns err != nil if and only if
the
> returned data does not end in delim")

Done.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode234
utils/tailer/tailer.go:234: t.readSeeker.Seek(offset, os.SEEK_END)
On 2013/12/10 15:14:25, rog wrote:
> This is racy. We can't seek from the end because the end might be
constantly
> changing. I think we need to keep track of where we're reading in the
file and
> seek back to the absolute offset of the start of the partial line.

Done.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode247
utils/tailer/tailer.go:247: return false
On 2013/12/10 15:14:25, rog wrote:
> Why?

Yeah, too much automatic filtering here. The receiver of the data should
decide. Removed it.

https://codereview.appspot.com/36540043/diff/40001/utils/tailer/tailer.go#newcode252
utils/tailer/tailer.go:252: return t.filter(line)
On 2013/12/10 15:14:25, rog wrote:
> Consider trimming \r?\n from the end of the line before calling
filter?

Why?

https://codereview.appspot.com/36540043/