Add the ability to attach remotely to a container

Also, you can now podman-remote run -it.  There are some bugs that need
to be ironed out but I would prefer to merge this so we can make both
progress on start and exec as well as the bugs.

* when doing podman-remote run -it foo /bin/bash, you have to press
enter to get the prompt to display. with the localized podman, we had to
teach it connect to the console first and then start the container so we
did not miss anything.

* when executing "exit" in the console, we get a hard lockup likely
because nobody knows what to do.

* custom detach keys are not supported

* podman-remote run -it alpine ls does not currently work.  only
dropping to a shell works.

Signed-off-by: baude <bbaude@redhat.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/pkg/varlinkapi/attach.go b/pkg/varlinkapi/attach.go
new file mode 100644
index 000000000..53c4d1ff6
--- /dev/null
+++ b/pkg/varlinkapi/attach.go
@@ -0,0 +1,75 @@
+// +build varlink
+
+package varlinkapi
+
+import (
+	"io"
+
+	"github.com/containers/libpod/cmd/podman/varlink"
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/pkg/varlinkapi/virtwriter"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+// Close is method to close the writer
+
+// Attach ...
+func (i *LibpodAPI) Attach(call iopodman.VarlinkCall, name string) error {
+	var finalErr error
+	resize := make(chan remotecommand.TerminalSize)
+	errChan := make(chan error)
+
+	if !call.WantsUpgrade() {
+		return call.ReplyErrorOccurred("client must use upgraded connection to attach")
+	}
+	ctr, err := i.Runtime.LookupContainer(name)
+	if err != nil {
+		return call.ReplyErrorOccurred(err.Error())
+	}
+
+	// These are the varlink sockets
+	reader := call.Call.Reader
+	writer := call.Call.Writer
+
+	// This pipe is used to pass stdin from the client to the input stream
+	// once the msg has been "decoded"
+	pr, pw := io.Pipe()
+
+	stdoutWriter := virtwriter.NewVirtWriteCloser(writer, virtwriter.ToStdout)
+	// TODO if runc ever starts passing stderr, we can too
+	//stderrWriter := NewVirtWriteCloser(writer, ToStderr)
+
+	streams := libpod.AttachStreams{
+		OutputStream: stdoutWriter,
+		InputStream:  pr,
+		// Runc eats the error stream
+		ErrorStream:  stdoutWriter,
+		AttachInput:  true,
+		AttachOutput: true,
+		// Runc eats the error stream
+		AttachError: true,
+	}
+
+	go func() {
+		if err := virtwriter.Reader(reader, nil, nil, pw, resize); err != nil {
+			errChan <- err
+		}
+	}()
+
+	go func() {
+		// TODO allow for customizable detach keys
+		if err := ctr.Attach(&streams, "", resize); err != nil {
+			errChan <- err
+		}
+	}()
+
+	select {
+	// Blocking on an error
+	case finalErr = <-errChan:
+		// Need to close up shop
+		_ = finalErr
+	}
+	quitWriter := virtwriter.NewVirtWriteCloser(writer, virtwriter.Quit)
+	_, err = quitWriter.Write([]byte("HANG-UP"))
+	return call.Writer.Flush()
+}