I have a function which returns the Reader end of an io.Pipe and kicks off a go-routine which writes data to the Writer end of it, and then closes the pipe.
func GetPipeReader() io.ReadCloser {
r, w := io.Pipe()
go func() {
_, err := io.CopyN(w, SomeReaderOfSize(N), N)
w.CloseWithError(err)
}()
return r
}
func main() {
var buf bytes.Buffer
io.Copy(&buf, GetPipeReader())
println("got", buf.Len(), "bytes")
}
https://play.golang.org/p/OAijIwmtRr
This seems to always work in my testing, in that I get all the data I wrote. But the API docs are a bit worrying to me:
func Pipe() (*PipeReader, *PipeWriter)
Pipe creates a synchronous in-memory pipe. [...] Reads on one end are matched with writes on the other, [...] there is no internal buffering.
func (w *PipeWriter) CloseWithError(err error) error
CloseWithError closes the writer; subsequent reads from the read half of the pipe will return no bytes and the error err, or EOF if err is nil.
What I want to know is, what are the possible race conditions here? Is is plausible that my go-routine will write a bunch of data and then close the pipe before I can read it all?
Do I need to use a channel for some signalling on when to close? What can go wrong, basically.
