buildkit/cmd/buildctl/dialstdio.go

132 lines
2.9 KiB
Go

package main
import (
"io"
"net"
"os"
"strings"
"time"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"github.com/urfave/cli"
)
var dialStdioCommand = cli.Command{
Name: "dial-stdio",
Usage: "Proxy the stdio stream to the daemon connection. Should not be invoked manually.",
Hidden: true,
Action: dialStdioAction,
}
func dialStdioAction(clicontext *cli.Context) error {
addr := clicontext.GlobalString("addr")
timeout := time.Duration(clicontext.GlobalInt("timeout")) * time.Second
conn, err := dialer(addr, timeout)
if err != nil {
return err
}
defer conn.Close()
var connHalfCloser halfCloser
switch t := conn.(type) {
case halfCloser:
connHalfCloser = t
case halfReadWriteCloser:
connHalfCloser = &nopCloseReader{t}
default:
return errors.New("the raw stream connection does not implement halfCloser")
}
stdin2conn := make(chan error, 1)
conn2stdout := make(chan error, 1)
go func() {
stdin2conn <- copier(connHalfCloser, &halfReadCloserWrapper{os.Stdin}, "stdin to stream")
}()
go func() {
conn2stdout <- copier(&halfWriteCloserWrapper{os.Stdout}, connHalfCloser, "stream to stdout")
}()
select {
case err = <-stdin2conn:
if err != nil {
return err
}
// wait for stdout
err = <-conn2stdout
case err = <-conn2stdout:
// return immediately without waiting for stdin to be closed.
// (stdin is never closed when tty)
}
return err
}
func dialer(address string, timeout time.Duration) (net.Conn, error) {
addrParts := strings.SplitN(address, "://", 2)
if len(addrParts) != 2 {
return nil, errors.Errorf("invalid address %s", address)
}
if addrParts[0] != "unix" {
return nil, errors.Errorf("invalid address %s (expected unix://, got %s://)", address, addrParts[0])
}
return net.DialTimeout(addrParts[0], addrParts[1], timeout)
}
func copier(to halfWriteCloser, from halfReadCloser, debugDescription string) error {
defer func() {
if err := from.CloseRead(); err != nil {
logrus.Errorf("error while CloseRead (%s): %v", debugDescription, err)
}
if err := to.CloseWrite(); err != nil {
logrus.Errorf("error while CloseWrite (%s): %v", debugDescription, err)
}
}()
if _, err := io.Copy(to, from); err != nil {
return errors.Wrapf(err, "error while Copy (%s)", debugDescription)
}
return nil
}
type halfReadCloser interface {
io.Reader
CloseRead() error
}
type halfWriteCloser interface {
io.Writer
CloseWrite() error
}
type halfCloser interface {
halfReadCloser
halfWriteCloser
}
type halfReadWriteCloser interface {
io.Reader
halfWriteCloser
}
type nopCloseReader struct {
halfReadWriteCloser
}
func (x *nopCloseReader) CloseRead() error {
return nil
}
type halfReadCloserWrapper struct {
io.ReadCloser
}
func (x *halfReadCloserWrapper) CloseRead() error {
return x.Close()
}
type halfWriteCloserWrapper struct {
io.WriteCloser
}
func (x *halfWriteCloserWrapper) CloseWrite() error {
return x.Close()
}