Merge branch 'exec' of https://github.com/fr05t1k/ctop into fr05t1k-exec

connector/manager/docker.go

@@ -3,6 +3,9 @@ package manager
 import (
 	"fmt"
 	api "github.com/fsouza/go-dockerclient"
+	"github.com/pkg/errors"
+	"io"
+	"os"
 )
 
 type Docker struct {
@@ -17,6 +20,85 @@ func NewDocker(client *api.Client, id string) *Docker {
 	}
 }
 
+// Do not allow to close reader (i.e. /dev/stdin which docker client tries to close after command execution)
+type noClosableReader struct {
+	wrappedReader io.Reader
+}
+
+func (w *noClosableReader) Read(p []byte) (n int, err error) {
+	return w.wrappedReader.Read(p)
+}
+
+const (
+	STDIN  = 0
+	STDOUT = 1
+	STDERR = 2
+)
+
+var (
+	wrongFrameFormat = errors.New("Wrong frame format")
+)
+
+// A frame has a Header and a Payload
+// Header: [8]byte{STREAM_TYPE, 0, 0, 0, SIZE1, SIZE2, SIZE3, SIZE4}
+// STREAM_TYPE can be:
+//    0: stdin (is written on stdout)
+//    1: stdout
+//    2: stderr
+// SIZE1, SIZE2, SIZE3, SIZE4 are the four bytes of the uint32 size encoded as big endian.
+// But we don't use size, because we don't need to find the end of frame.
+type frameWriter struct {
+	stdout io.Writer
+	stderr io.Writer
+	stdin  io.Writer
+}
+
+func (w *frameWriter) Write(p []byte) (n int, err error) {
+	if len(p) > 8 {
+		var targetWriter io.Writer
+		switch p[0] {
+		case STDIN:
+			targetWriter = w.stdin
+			break
+		case STDOUT:
+			targetWriter = w.stdout
+			break
+		case STDERR:
+			targetWriter = w.stderr
+			break
+		default:
+			return 0, wrongFrameFormat
+		}
+
+		n, err := targetWriter.Write(p[8:])
+		return n + 8, err
+	}
+
+	return 0, wrongFrameFormat
+}
+
+func (dc *Docker) Exec(cmd []string) error {
+	execCmd, err := dc.client.CreateExec(api.CreateExecOptions{
+		AttachStdin:  true,
+		AttachStdout: true,
+		AttachStderr: true,
+		Cmd:          cmd,
+		Container:    dc.id,
+		Tty:          true,
+	})
+
+	if err != nil {
+		return err
+	}
+
+	return dc.client.StartExec(execCmd.ID, api.StartExecOptions{
+		InputStream:  &noClosableReader{os.Stdin},
+		OutputStream: &frameWriter{os.Stdout, os.Stderr, os.Stdin},
+		ErrorStream:  os.Stderr,
+		RawTerminal:  true,
+	})
+}
+
 func (dc *Docker) Start() error {
 	c, err := dc.client.InspectContainer(dc.id)
 	if err != nil {

connector/manager/main.go

@@ -7,4 +7,5 @@ type Manager interface {
 	Pause() error
 	Unpause() error
 	Restart() error
+	Exec(cmd []string) error
 }

connector/manager/mock.go

@@ -29,3 +29,7 @@ func (m *Mock) Unpause() error {
 func (m *Mock) Restart() error {
 	return nil
 }
+
+func (m *Mock) Exec(cmd []string) error {
+	return nil
+}

connector/manager/runc.go

@@ -29,3 +29,7 @@ func (rc *Runc) Unpause() error {
 func (rc *Runc) Restart() error {
 	return nil
 }
+
+func (rc *Runc) Exec(cmd []string) error {
+	return nil
+}