// Signallistener returns a net.Listener that will be closed when standard OS
// stop signals are received.
func SignalListener(port int) (net.Listener, error) {
addr := ":" + fmt.Sprint(port)
l, err := net.Listen("tcp", addr)
if err != nil {
log.Errorln("govtil/net: Failed to listen on", port, err)
return nil, err
}
// Close listen port on signals (causes http.Serve() to return)
signal.Go(func(s os.Signal) {
log.Debugf("govtil/net: Closing listen port %v due to signal %v", l.Addr().String(), s)
l.Close()
})
return l, nil
}
// Split a ReadCloser into 'n' ReadClosers. When all returned ReadClosers have
// been Close()'d, then the underlying ReadCloser is also closed.
func SplitReadCloser(rc io.ReadCloser, n uint) []io.ReadCloser {
var r []io.ReadCloser
var w []io.WriteCloser
cg := new(sync.WaitGroup)
cg.Add(int(n))
for i := 0; i < int(n); i++ {
rp, wp := io.Pipe()
brp := bufio.NewReader(rp)
w = append(w, wp)
rpx := &rproxy{
i,
rp,
brp,
cg,
}
r = append(r, rpx)
}
// Closer
go func() {
cg.Wait()
rc.Close()
}()
// Read pump
rpump := func() {
var err error
defer func() {
if err != nil && err != io.EOF {
log.Errorf("govtil/io/multiplex: rpump error: %v", err)
}
for i := 0; i < len(w); i++ {
w[i].Close()
}
}()
dec := gob.NewDecoder(rc)
var chno uint
var d []byte
for {
if err = dec.Decode(&chno); err != nil {
return
}
if err = dec.Decode(&d); err != nil {
return
}
if _, err = w[chno].Write(d); err != nil {
if err == io.ErrClosedPipe {
// closed sub-channel, keep serving other sub-channels
log.Debugf("govtil/io/multiplex: sub-channel closed, dumping payload of len %v", len(d))
continue
} else {
// something wrong, stop
log.Debugf("govtil/io/multiplex: failed to write received payload of length %v to pipe for channel %v", len(d), chno)
return
}
}
}
}
go rpump()
return r
}