// stdouterrAccept runs as a go function. It waits for the container system to
// accept our offer of a named pipe - in fact two of them - one for stdout
// and one for stderr (we are called twice). Once the named pipe is accepted,
// if we are running "attached" to the container (eg docker run -i), then we
// spin up a further thread to copy anything from the containers output channels
// to the client.
func stdouterrAccept(outerrListen *npipe.PipeListener, pipeName string, copyto io.Writer) {
// Wait for the pipe to be connected to by the shim
logrus.Debugln("out/err: Waiting on ", pipeName)
outerrConn, err := outerrListen.Accept()
if err != nil {
logrus.Errorf("Failed to accept on pipe %s %s", pipeName, err)
return
}
logrus.Debugln("Connected to ", outerrConn.RemoteAddr())
// Anything that comes from the container named pipe stdout/err should be copied
// across to the stdout/err of the client
if copyto != nil {
go func() {
defer outerrConn.Close()
logrus.Debugln("Calling io.Copy on ", pipeName)
bytes, err := io.Copy(copyto, outerrConn)
logrus.Debugf("Copied %d bytes from pipe=%s", bytes, outerrConn.RemoteAddr())
if err != nil {
// Not fatal, just debug log it
logrus.Debugf("Error hit during copy %s", err)
}
}()
} else {
defer outerrConn.Close()
}
}
// stdinAccept runs as a go function. It waits for the container system
// to accept our offer of a named pipe for stdin. Once accepted, if we are
// running "attached" to the container (eg docker run -i), then we spin up
// a further thread to copy anything from the client into the container.
//
// Important design note. This function is run as a go function for a very
// good reason. The named pipe Accept call is blocking until one of two things
// happen. Either someone connects to it, or it is forcibly closed. Let's
// assume that no-one connects to it, the only way otherwise the Run()
// method would continue is by closing it. However, as that would be the same
// thread, it can't close it. Hence we run as another thread allowing Run()
// to close the named pipe.
func stdinAccept(inListen *npipe.PipeListener, pipeName string, copyfrom io.ReadCloser) {
// Wait for the pipe to be connected to by the shim
logrus.Debugln("stdinAccept: Waiting on ", pipeName)
stdinConn, err := inListen.Accept()
if err != nil {
logrus.Errorf("Failed to accept on pipe %s %s", pipeName, err)
return
}
logrus.Debugln("Connected to ", stdinConn.RemoteAddr())
// Anything that comes from the client stdin should be copied
// across to the stdin named pipe of the container.
if copyfrom != nil {
go func() {
defer stdinConn.Close()
logrus.Debugln("Calling io.Copy on stdin")
bytes, err := io.Copy(stdinConn, copyfrom)
logrus.Debugf("Finished io.Copy on stdin bytes=%d err=%s pipe=%s", bytes, err, stdinConn.RemoteAddr())
}()
} else {
defer stdinConn.Close()
}
}