WIP V2 attach bindings and test

* Add ErrLostSync to report lost of sync when de-mux'ing stream
* Add logus.SetLevel(logrus.DebugLevel) when `go test -v` given
* Add context to debugging messages

Signed-off-by: Jhon Honce <jhonce@redhat.com>

5 files changed, 200 insertions, 2 deletions

diff --git a/pkg/bindings/containers/containers.go b/pkg/bindings/containers/containers.go
index e74a256c7..de7b792b4 100644
--- a/pkg/bindings/containers/containers.go
+++ b/pkg/bindings/containers/containers.go
@@ -2,6 +2,8 @@ package containers
 
 import (
 	"context"
+	"encoding/binary"
+	"fmt"
 	"io"
 	"net/http"
 	"net/url"
@@ -15,6 +17,10 @@ import (
 	"github.com/pkg/errors"
 )
 
+var (
+	ErrLostSync = errors.New("lost synchronization with attach multiplexed result")
+)
+
 // List obtains a list of containers in local storage.  All parameters to this method are optional.
 // The filters are used to determine which containers are listed. The last parameter indicates to only return
 // the most recent number of containers.  The pod and size booleans indicate that pod information and rootfs
@@ -247,7 +253,7 @@ func Unpause(ctx context.Context, nameOrID string) error {
 // Wait blocks until the given container reaches a condition. If not provided, the condition will
 // default to stopped.  If the condition is stopped, an exit code for the container will be provided. The
 // nameOrID can be a container name or a partial/full ID.
-func Wait(ctx context.Context, nameOrID string, condition *define.ContainerStatus) (int32, error) { //nolint
+func Wait(ctx context.Context, nameOrID string, condition *define.ContainerStatus) (int32, error) { // nolint
 	var exitCode int32
 	conn, err := bindings.GetClient(ctx)
 	if err != nil {
@@ -333,3 +339,125 @@ func ContainerInit(ctx context.Context, nameOrID string) error {
 	}
 	return response.Process(nil)
 }
+
+// Attach attaches to a running container
+func Attach(ctx context.Context, nameOrId string, detachKeys *string, logs, stream *bool, stdin *bool, stdout io.Writer, stderr io.Writer) error {
+	conn, err := bindings.GetClient(ctx)
+	if err != nil {
+		return err
+	}
+
+	params := url.Values{}
+	if detachKeys != nil {
+		params.Add("detachKeys", *detachKeys)
+	}
+	if logs != nil {
+		params.Add("logs", fmt.Sprintf("%t", *logs))
+	}
+	if stream != nil {
+		params.Add("stream", fmt.Sprintf("%t", *stream))
+	}
+	if stdin != nil && *stdin {
+		params.Add("stdin", "true")
+	}
+	if stdout != nil {
+		params.Add("stdout", "true")
+	}
+	if stderr != nil {
+		params.Add("stderr", "true")
+	}
+
+	response, err := conn.DoRequest(nil, http.MethodPost, "/containers/%s/attach", params, nameOrId)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	ctype := response.Header.Get("Content-Type")
+	upgrade := response.Header.Get("Connection")
+
+	buffer := make([]byte, 1024)
+	if ctype == "application/vnd.docker.raw-stream" && upgrade == "Upgrade" {
+		for {
+			// Read multiplexed channels and write to appropriate stream
+			fd, l, err := DemuxHeader(response.Body, buffer)
+			if err != nil {
+				switch {
+				case errors.Is(err, io.EOF):
+					return nil
+				case errors.Is(err, io.ErrUnexpectedEOF):
+					continue
+				}
+				return err
+			}
+			frame, err := DemuxFrame(response.Body, buffer, l)
+			if err != nil {
+				return err
+			}
+
+			switch {
+			case fd == 0 && stdin != nil && *stdin:
+				stdout.Write(frame)
+			case fd == 1 && stdout != nil:
+				stdout.Write(frame)
+			case fd == 2 && stderr != nil:
+				stderr.Write(frame)
+			case fd == 3:
+				return fmt.Errorf("error from daemon in stream: %s", frame)
+			default:
+				return fmt.Errorf("unrecognized input header: %d", fd)
+			}
+		}
+	} else {
+		// If not multiplex'ed from server just dump stream to stdout
+		for {
+			_, err := response.Body.Read(buffer)
+			if err != nil {
+				if !errors.Is(err, io.EOF) {
+					return err
+				}
+				break
+			}
+			stdout.Write(buffer)
+		}
+	}
+	return err
+}
+
+// DemuxHeader reads header for stream from server multiplexed stdin/stdout/stderr/2nd error channel
+func DemuxHeader(r io.Reader, buffer []byte) (fd, sz int, err error) {
+	n, err := io.ReadFull(r, buffer[0:8])
+	if err != nil {
+		return
+	}
+	if n < 8 {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+
+	fd = int(buffer[0])
+	if fd < 0 || fd > 3 {
+		err = ErrLostSync
+		return
+	}
+
+	sz = int(binary.BigEndian.Uint32(buffer[4:8]))
+	return
+}
+
+// DemuxFrame reads contents for frame from server multiplexed stdin/stdout/stderr/2nd error channel
+func DemuxFrame(r io.Reader, buffer []byte, length int) (frame []byte, err error) {
+	if len(buffer) < length {
+		buffer = append(buffer, make([]byte, length-len(buffer)+1)...)
+	}
+	n, err := io.ReadFull(r, buffer[0:length])
+	if err != nil {
+		return nil, nil
+	}
+	if n < length {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+
+	return buffer[0:length], nil
+}
diff --git a/pkg/bindings/test/attach_test.go b/pkg/bindings/test/attach_test.go
new file mode 100644
index 000000000..8e89ff8ff
--- /dev/null
+++ b/pkg/bindings/test/attach_test.go
@@ -0,0 +1,63 @@
+package test_bindings
+
+import (
+	"bytes"
+	"time"
+
+	"github.com/containers/libpod/pkg/bindings"
+	"github.com/containers/libpod/pkg/bindings/containers"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gexec"
+)
+
+var _ = Describe("Podman containers attach", func() {
+	var (
+		bt *bindingTest
+		s  *gexec.Session
+	)
+
+	BeforeEach(func() {
+		bt = newBindingTest()
+		bt.RestoreImagesFromCache()
+		s = bt.startAPIService()
+		time.Sleep(1 * time.Second)
+		err := bt.NewConnection()
+		Expect(err).ShouldNot(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		s.Kill()
+		bt.cleanup()
+	})
+
+	It("attach", func() {
+		name := "TopAttachTest"
+		id, err := bt.RunTopContainer(&name, nil, nil)
+		Expect(err).ShouldNot(HaveOccurred())
+
+		tickTock := time.NewTimer(2 * time.Second)
+		go func() {
+			<-tickTock.C
+			timeout := uint(5)
+			err := containers.Stop(bt.conn, id, &timeout)
+			if err != nil {
+				GinkgoWriter.Write([]byte(err.Error()))
+			}
+		}()
+
+		stdout := &bytes.Buffer{}
+		stderr := &bytes.Buffer{}
+		go func() {
+			defer GinkgoRecover()
+
+			err := containers.Attach(bt.conn, id, nil, &bindings.PTrue, &bindings.PTrue, &bindings.PTrue, stdout, stderr)
+			Expect(err).ShouldNot(HaveOccurred())
+		}()
+
+		time.Sleep(5 * time.Second)
+
+		// First character/First line of top output
+		Expect(stdout.String()).Should(ContainSubstring("Mem: "))
+	})
+})
diff --git a/pkg/bindings/test/common_test.go b/pkg/bindings/test/common_test.go
index f33e42440..a86e6f2e3 100644
--- a/pkg/bindings/test/common_test.go
+++ b/pkg/bindings/test/common_test.go
@@ -191,7 +191,7 @@ func (b *bindingTest) restoreImageFromCache(i testImage) {
 func (b *bindingTest) RunTopContainer(containerName *string, insidePod *bool, podName *string) (string, error) {
 	s := specgen.NewSpecGenerator(alpine.name, false)
 	s.Terminal = false
-	s.Command = []string{"top"}
+	s.Command = []string{"/usr/bin/top"}
 	if containerName != nil {
 		s.Name = *containerName
 	}
diff --git a/pkg/bindings/test/containers_test.go b/pkg/bindings/test/containers_test.go
index 328691df2..d130c146a 100644
--- a/pkg/bindings/test/containers_test.go
+++ b/pkg/bindings/test/containers_test.go
@@ -302,6 +302,8 @@ var _ = Describe("Podman containers ", func() {
 
 		errChan = make(chan error)
 		go func() {
+			defer GinkgoRecover()
+
 			_, waitErr := containers.Wait(bt.conn, name, &running)
 			errChan <- waitErr
 			close(errChan)
diff --git a/pkg/bindings/test/test_suite_test.go b/pkg/bindings/test/test_suite_test.go
index dc2b49b88..d2c2c7838 100644
--- a/pkg/bindings/test/test_suite_test.go
+++ b/pkg/bindings/test/test_suite_test.go
@@ -5,9 +5,14 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/sirupsen/logrus"
 )
 
 func TestTest(t *testing.T) {
+	if testing.Verbose() {
+		logrus.SetLevel(logrus.DebugLevel)
+	}
+
 	RegisterFailHandler(Fail)
 	RunSpecs(t, "Test Suite")
 }