pipe_closer_thinger.go

package main

import (
	"io"
	"log"
)

func main() {

	w := sink()
	for i := 0; i < 10; i++ {

		if _, err := w.Write(make([]byte, 1011)); err != nil {

			log.Printf("Failed to write: %v\n", err)
		}
	}

	if err := w.Close(); err != nil {

		log.Printf("Failed to close sink: %v\n", err)
	}
}

func sink() io.WriteCloser {

	r, w := io.Pipe()
	c := make(chan struct{})
	go func() {
		defer close(c)

		buf := make([]byte, 1024)
		for {

			_, err := r.Read(buf)
			if err != nil {

				if err == io.EOF {

					log.Println("Writer Complete")
					return
				}

				log.Printf("Writer abated with %v\n", err)
				if err := w.CloseWithError(err); err != nil {

					log.Printf("Failed to close writer: %v\n", err)
				}
				return
			}
		}
	}()

	return &syncWriteCloser{w: w, c: c}
}

type syncWriteCloser struct {
	w io.WriteCloser
	c chan struct{}
}

func (w *syncWriteCloser) Write(data []byte) (n int, err error) {

	n, err = w.w.Write(data)
	return
}

func (w *syncWriteCloser) Close() error {

	err := w.w.Close()
	for range w.c {
	}

	return err
}