Merge pull request #4837 from mheon/rework_attach

Add an API for Attach over HTTP API

14 files changed, 950 insertions, 2 deletions

diff --git a/go.mod b/go.mod
index dff9ab4f3..1f89eb89f 100644
--- a/go.mod
+++ b/go.mod
@@ -11,6 +11,7 @@ require (
 	github.com/containernetworking/cni v0.7.2-0.20190904153231-83439463f784
 	github.com/containernetworking/plugins v0.8.2
 	github.com/containers/buildah v1.13.1
+	github.com/containers/conmon v2.0.9+incompatible
 	github.com/containers/image/v5 v5.1.0
 	github.com/containers/psgo v1.4.0
 	github.com/containers/storage v1.15.5
diff --git a/go.sum b/go.sum
index f3613ce2e..f1d6f1c78 100644
--- a/go.sum
+++ b/go.sum
@@ -81,6 +81,8 @@ github.com/containers/common v0.0.3 h1:C2Zshb0w720FqPa42MCRuiGfbW0kwbURRwvK1EWIC
 github.com/containers/common v0.0.3/go.mod h1:CaOgMRiwi2JJHISMZ6VPPZhQYFUDRv3YYVss2RqUCMg=
 github.com/containers/common v0.0.7 h1:eKYZLKfJ2d/RNDgecLDFv45cHb4imYzIcrQHx1Y029M=
 github.com/containers/common v0.0.7/go.mod h1:lhWV3MLhO1+KGE2x6v9+K38MxpjXGso+edmpkFnCOqI=
+github.com/containers/conmon v2.0.9+incompatible h1:YcEgk0Ny1WBdH35M2LKe2cG6FiQqzDdVaURw84XvS7A=
+github.com/containers/conmon v2.0.9+incompatible/go.mod h1:hgwZ2mtuDrppv78a/cOBNiCm6O0UMWGx1mu7P00nu5I=
 github.com/containers/image/v5 v5.0.0 h1:arnXgbt1ucsC/ndtSpiQY87rA0UjhF+/xQnPzqdBDn4=
 github.com/containers/image/v5 v5.0.0/go.mod h1:MgiLzCfIeo8lrHi+4Lb8HP+rh513sm0Mlk6RrhjFOLY=
 github.com/containers/image/v5 v5.1.0 h1:5FjAvPJniamuNNIQHkh4PnsL+n+xzs6Aonzaz5dqTEo=
diff --git a/libpod/container_api.go b/libpod/container_api.go
index e36623529..d74a14f15 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"io"
 	"io/ioutil"
+	"net"
 	"os"
 	"time"
 
@@ -374,7 +375,9 @@ type AttachStreams struct {
 	AttachInput bool
 }
 
-// Attach attaches to a container
+// Attach attaches to a container.
+// This function returns when the attach finishes. It does not hold the lock for
+// the duration of its runtime, only using it at the beginning to verify state.
 func (c *Container) Attach(streams *AttachStreams, keys string, resize <-chan remotecommand.TerminalSize) error {
 	if !c.batched {
 		c.lock.Lock()
@@ -382,6 +385,7 @@ func (c *Container) Attach(streams *AttachStreams, keys string, resize <-chan re
 			c.lock.Unlock()
 			return err
 		}
+		// We are NOT holding the lock for the duration of the function.
 		c.lock.Unlock()
 	}
 
@@ -389,10 +393,71 @@ func (c *Container) Attach(streams *AttachStreams, keys string, resize <-chan re
 		return errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers")
 	}
 
-	defer c.newContainerEvent(events.Attach)
+	c.newContainerEvent(events.Attach)
 	return c.attach(streams, keys, resize, false, nil)
 }
 
+// HTTPAttach forwards an attach session over a hijacked HTTP session.
+// HTTPAttach will consume and close the included httpCon, which is expected to
+// be sourced from a hijacked HTTP connection.
+// The cancel channel is optional, and can be used to asyncronously cancel the
+// attach session.
+// The streams variable is only supported if the container was not a terminal,
+// and allows specifying which of the container's standard streams will be
+// forwarded to the client.
+// This function returns when the attach finishes. It does not hold the lock for
+// the duration of its runtime, only using it at the beginning to verify state.
+func (c *Container) HTTPAttach(httpCon net.Conn, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool) error {
+	if !c.batched {
+		c.lock.Lock()
+		if err := c.syncContainer(); err != nil {
+			c.lock.Unlock()
+
+			// Write any errors to the HTTP buffer before we close.
+			hijackWriteErrorAndClose(err, c.ID(), httpCon, httpBuf)
+
+			return err
+		}
+		// We are NOT holding the lock for the duration of the function.
+		c.lock.Unlock()
+	}
+
+	if !c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning) {
+		toReturn := errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers")
+
+		// Write any errors to the HTTP buffer before we close.
+		hijackWriteErrorAndClose(toReturn, c.ID(), httpCon, httpBuf)
+
+		return toReturn
+	}
+
+	logrus.Infof("Performing HTTP Hijack attach to container %s", c.ID())
+
+	c.newContainerEvent(events.Attach)
+	return c.ociRuntime.HTTPAttach(c, httpCon, httpBuf, streams, detachKeys, cancel)
+}
+
+// AttachResize resizes the container's terminal, which is displayed by Attach
+// and HTTPAttach.
+func (c *Container) AttachResize(newSize remotecommand.TerminalSize) error {
+	if !c.batched {
+		c.lock.Lock()
+		defer c.lock.Unlock()
+
+		if err := c.syncContainer(); err != nil {
+			return err
+		}
+	}
+
+	if !c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning) {
+		return errors.Wrapf(define.ErrCtrStateInvalid, "can only resize created or running containers")
+	}
+
+	logrus.Infof("Resizing TTY of container %s", c.ID())
+
+	return c.ociRuntime.AttachResize(c, newSize)
+}
+
 // Mount mounts a container's filesystem on the host
 // The path where the container has been mounted is returned
 func (c *Container) Mount() (string, error) {
diff --git a/libpod/oci.go b/libpod/oci.go
index 05a2f37db..2ea61851f 100644
--- a/libpod/oci.go
+++ b/libpod/oci.go
@@ -1,6 +1,9 @@
 package libpod
 
 import (
+	"bufio"
+	"net"
+
 	"k8s.io/client-go/tools/remotecommand"
 )
 
@@ -47,6 +50,23 @@ type OCIRuntime interface {
 	// UnpauseContainer unpauses the given container.
 	UnpauseContainer(ctr *Container) error
 
+	// HTTPAttach performs an attach intended to be transported over HTTP.
+	// For terminal attach, the container's output will be directly streamed
+	// to output; otherwise, STDOUT and STDERR will be multiplexed, with
+	// a header prepended as follows: 1-byte STREAM (0, 1, 2 for STDIN,
+	// STDOUT, STDERR), 3 null (0x00) bytes, 4-byte big endian length.
+	// If a cancel channel is provided, it can be used to asyncronously
+	// termninate the attach session. Detach keys, if given, will also cause
+	// the attach session to be terminated if provided via the STDIN
+	// channel. If they are not provided, the default detach keys will be
+	// used instead. Detach keys of "" will disable detaching via keyboard.
+	// The streams parameter may be passed for containers that did not
+	// create a terminal and will determine which streams to forward to the
+	// client.
+	HTTPAttach(ctr *Container, httpConn net.Conn, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool) error
+	// AttachResize resizes the terminal in use by the given container.
+	AttachResize(ctr *Container, newSize remotecommand.TerminalSize) error
+
 	// ExecContainer executes a command in a running container.
 	// Returns an int (exit code), error channel (errors from attach), and
 	// error (errors that occurred attempting to start the exec session).
@@ -130,3 +150,12 @@ type ExecOptions struct {
 	// detach from the container.
 	DetachKeys string
 }
+
+// HTTPAttachStreams informs the HTTPAttach endpoint which of the container's
+// standard streams should be streamed to the client. If this is passed, at
+// least one of the streams must be set to true.
+type HTTPAttachStreams struct {
+	Stdin  bool
+	Stdout bool
+	Stderr bool
+}
diff --git a/libpod/oci_conmon_linux.go b/libpod/oci_conmon_linux.go
index 5ab0e73c4..0e8a64865 100644
--- a/libpod/oci_conmon_linux.go
+++ b/libpod/oci_conmon_linux.go
@@ -5,8 +5,11 @@ package libpod
 import (
 	"bufio"
 	"bytes"
+	"encoding/binary"
 	"fmt"
+	"io"
 	"io/ioutil"
+	"net"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -17,6 +20,7 @@ import (
 	"text/template"
 	"time"
 
+	conmonConfig "github.com/containers/conmon/runner/config"
 	"github.com/containers/libpod/libpod/config"
 	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/pkg/cgroups"
@@ -33,6 +37,13 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+const (
+	// This is Conmon's STDIO_BUF_SIZE. I don't believe we have access to it
+	// directly from the Go cose, so const it here
+	bufferSize = conmonConfig.BufSize
 )
 
 // ConmonOCIRuntime is an OCI runtime managed by Conmon.
@@ -465,6 +476,123 @@ func (r *ConmonOCIRuntime) UnpauseContainer(ctr *Container) error {
 	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, "resume", ctr.ID())
 }
 
+// HTTPAttach performs an attach for the HTTP API.
+// This will consume, and automatically close, the hijacked HTTP session.
+// It is not necessary to close it independently.
+// The cancel channel is not closed; it is up to the caller to do so after
+// this function returns.
+// If this is a container with a terminal, we will stream raw. If it is not, we
+// will stream with an 8-byte header to multiplex STDOUT and STDERR.
+func (r *ConmonOCIRuntime) HTTPAttach(ctr *Container, httpConn net.Conn, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool) (deferredErr error) {
+	isTerminal := false
+	if ctr.config.Spec.Process != nil {
+		isTerminal = ctr.config.Spec.Process.Terminal
+	}
+
+	// Ensure that our contract of closing the HTTP connection is honored.
+	defer hijackWriteErrorAndClose(deferredErr, ctr.ID(), httpConn, httpBuf)
+
+	if streams != nil {
+		if isTerminal {
+			return errors.Wrapf(define.ErrInvalidArg, "cannot specify which streams to attach as container %s has a terminal", ctr.ID())
+		}
+		if !streams.Stdin && !streams.Stdout && !streams.Stderr {
+			return errors.Wrapf(define.ErrInvalidArg, "must specify at least one stream to attach to")
+		}
+	}
+
+	attachSock, err := r.AttachSocketPath(ctr)
+	if err != nil {
+		return err
+	}
+	socketPath := buildSocketPath(attachSock)
+
+	conn, err := net.DialUnix("unixpacket", nil, &net.UnixAddr{Name: socketPath, Net: "unixpacket"})
+	if err != nil {
+		return errors.Wrapf(err, "failed to connect to container's attach socket: %v", socketPath)
+	}
+	defer func() {
+		if err := conn.Close(); err != nil {
+			logrus.Errorf("unable to close container %s attach socket: %q", ctr.ID(), err)
+		}
+	}()
+
+	logrus.Debugf("Successfully connected to container %s attach socket %s", ctr.ID(), socketPath)
+
+	detachString := define.DefaultDetachKeys
+	if detachKeys != nil {
+		detachString = *detachKeys
+	}
+	detach, err := processDetachKeys(detachString)
+	if err != nil {
+		return err
+	}
+
+	// Make a channel to pass errors back
+	errChan := make(chan error)
+
+	attachStdout := true
+	attachStderr := true
+	attachStdin := true
+	if streams != nil {
+		attachStdout = streams.Stdout
+		attachStderr = streams.Stderr
+		attachStdin = streams.Stdin
+	}
+
+	// Handle STDOUT/STDERR
+	go func() {
+		var err error
+		if isTerminal {
+			logrus.Debugf("Performing terminal HTTP attach for container %s", ctr.ID())
+			err = httpAttachTerminalCopy(conn, httpBuf, ctr.ID())
+		} else {
+			logrus.Debugf("Performing non-terminal HTTP attach for container %s", ctr.ID())
+			err = httpAttachNonTerminalCopy(conn, httpBuf, ctr.ID(), attachStdin, attachStdout, attachStderr)
+		}
+		errChan <- err
+		logrus.Debugf("STDOUT/ERR copy completed")
+	}()
+	// Next, STDIN. Avoid entirely if attachStdin unset.
+	if attachStdin {
+		go func() {
+			_, err := utils.CopyDetachable(conn, httpBuf, detach)
+			logrus.Debugf("STDIN copy completed")
+			errChan <- err
+		}()
+	}
+
+	if cancel != nil {
+		select {
+		case err := <-errChan:
+			return err
+		case <-cancel:
+			return nil
+		}
+	} else {
+		var connErr error = <-errChan
+		return connErr
+	}
+}
+
+// AttachResize resizes the terminal used by the given container.
+func (r *ConmonOCIRuntime) AttachResize(ctr *Container, newSize remotecommand.TerminalSize) error {
+	// TODO: probably want a dedicated function to get ctl file path?
+	controlPath := filepath.Join(ctr.bundlePath(), "ctl")
+	controlFile, err := os.OpenFile(controlPath, unix.O_WRONLY, 0)
+	if err != nil {
+		return errors.Wrapf(err, "could not open ctl file for terminal resize")
+	}
+	defer controlFile.Close()
+
+	logrus.Debugf("Received a resize event for container %s: %+v", ctr.ID(), newSize)
+	if _, err = fmt.Fprintf(controlFile, "%d %d %d\n", 1, newSize.Height, newSize.Width); err != nil {
+		return errors.Wrapf(err, "failed to write to ctl file to resize terminal")
+	}
+
+	return nil
+}
+
 // ExecContainer executes a command in a running container
 // TODO: Split into Create/Start/Attach/Wait
 func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options *ExecOptions) (int, chan error, error) {
@@ -1465,3 +1593,139 @@ func (r *ConmonOCIRuntime) getOCIRuntimeVersion() (string, error) {
 	}
 	return strings.TrimSuffix(output, "\n"), nil
 }
+
+// Copy data from container to HTTP connection, for terminal attach.
+// Container is the container's attach socket connection, http is a buffer for
+// the HTTP connection. cid is the ID of the container the attach session is
+// running for (used solely for error messages).
+func httpAttachTerminalCopy(container *net.UnixConn, http *bufio.ReadWriter, cid string) error {
+	buf := make([]byte, bufferSize)
+	for {
+		numR, err := container.Read(buf)
+		if numR > 0 {
+			switch buf[0] {
+			case AttachPipeStdout:
+				// Do nothing
+			default:
+				logrus.Errorf("Received unexpected attach type %+d, discarding %d bytes", buf[0], numR)
+				continue
+			}
+
+			numW, err2 := http.Write(buf[1:numR])
+			if err2 != nil {
+				if err != nil {
+					logrus.Errorf("Error reading container %s STDOUT: %v", cid, err)
+				}
+				return err2
+			} else if numW+1 != numR {
+				return io.ErrShortWrite
+			}
+			// We need to force the buffer to write immediately, so
+			// there isn't a delay on the terminal side.
+			if err2 := http.Flush(); err2 != nil {
+				if err != nil {
+					logrus.Errorf("Error reading container %s STDOUT: %v", cid, err)
+				}
+				return err2
+			}
+		}
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+	}
+}
+
+// Copy data from a container to an HTTP connection, for non-terminal attach.
+// Appends a header to multiplex input.
+func httpAttachNonTerminalCopy(container *net.UnixConn, http *bufio.ReadWriter, cid string, stdin, stdout, stderr bool) error {
+	buf := make([]byte, bufferSize)
+	for {
+		numR, err := container.Read(buf)
+		if numR > 0 {
+			headerBuf := []byte{0, 0, 0, 0}
+
+			// Practically speaking, we could make this buf[0] - 1,
+			// but we need to validate it anyways...
+			switch buf[0] {
+			case AttachPipeStdin:
+				headerBuf[0] = 0
+				if !stdin {
+					continue
+				}
+			case AttachPipeStdout:
+				if !stdout {
+					continue
+				}
+				headerBuf[0] = 1
+			case AttachPipeStderr:
+				if !stderr {
+					continue
+				}
+				headerBuf[0] = 2
+			default:
+				logrus.Errorf("Received unexpected attach type %+d, discarding %d bytes", buf[0], numR)
+				continue
+			}
+
+			// Get big-endian length and append.
+			// Subtract 1 because we strip the first byte (used for
+			// multiplexing by Conmon).
+			lenBuf := []byte{0, 0, 0, 0}
+			binary.BigEndian.PutUint32(lenBuf, uint32(numR-1))
+			headerBuf = append(headerBuf, lenBuf...)
+
+			numH, err2 := http.Write(headerBuf)
+			if err2 != nil {
+				if err != nil {
+					logrus.Errorf("Error reading container %s standard streams: %v", cid, err)
+				}
+
+				return err2
+			}
+			// Hardcoding header length is pretty gross, but
+			// fast. Should be safe, as this is a fixed part
+			// of the protocol.
+			if numH != 8 {
+				if err != nil {
+					logrus.Errorf("Error reading container %s standard streams: %v", cid, err)
+				}
+
+				return io.ErrShortWrite
+			}
+
+			numW, err2 := http.Write(buf[1:numR])
+			if err2 != nil {
+				if err != nil {
+					logrus.Errorf("Error reading container %s standard streams: %v", cid, err)
+				}
+
+				return err2
+			} else if numW+1 != numR {
+				if err != nil {
+					logrus.Errorf("Error reading container %s standard streams: %v", cid, err)
+				}
+
+				return io.ErrShortWrite
+			}
+			// We need to force the buffer to write immediately, so
+			// there isn't a delay on the terminal side.
+			if err2 := http.Flush(); err2 != nil {
+				if err != nil {
+					logrus.Errorf("Error reading container %s STDOUT: %v", cid, err)
+				}
+				return err2
+			}
+		}
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+
+			return err
+		}
+	}
+
+}
diff --git a/libpod/oci_missing.go b/libpod/oci_missing.go
index 0faa1805b..ff7eea625 100644
--- a/libpod/oci_missing.go
+++ b/libpod/oci_missing.go
@@ -1,13 +1,16 @@
 package libpod
 
 import (
+	"bufio"
 	"fmt"
+	"net"
 	"path/filepath"
 	"sync"
 
 	"github.com/containers/libpod/libpod/define"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
+	"k8s.io/client-go/tools/remotecommand"
 )
 
 var (
@@ -107,6 +110,16 @@ func (r *MissingRuntime) UnpauseContainer(ctr *Container) error {
 	return r.printError()
 }
 
+// HTTPAttach is not available as the runtime is missing
+func (r *MissingRuntime) HTTPAttach(ctr *Container, httpConn net.Conn, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, detachKeys *string, cancel <-chan bool) error {
+	return r.printError()
+}
+
+// AttachResize is not available as the runtime is missing
+func (r *MissingRuntime) AttachResize(ctr *Container, newSize remotecommand.TerminalSize) error {
+	return r.printError()
+}
+
 // ExecContainer is not available as the runtime is missing
 func (r *MissingRuntime) ExecContainer(ctr *Container, sessionID string, options *ExecOptions) (int, chan error, error) {
 	return -1, nil, r.printError()
diff --git a/libpod/util.go b/libpod/util.go
index 30e5cd4c3..f79d6c09b 100644
--- a/libpod/util.go
+++ b/libpod/util.go
@@ -1,7 +1,9 @@
 package libpod
 
 import (
+	"bufio"
 	"fmt"
+	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -16,6 +18,7 @@ import (
 	"github.com/fsnotify/fsnotify"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
 // Runtime API constants
@@ -231,3 +234,20 @@ func checkDependencyContainer(depCtr, ctr *Container) error {
 
 	return nil
 }
+
+// hijackWriteErrorAndClose writes an error to a hijacked HTTP session and
+// closes it. Intended to HTTPAttach function.
+// If error is nil, it will not be written; we'll only close the connection.
+func hijackWriteErrorAndClose(toWrite error, cid string, httpCon io.Closer, httpBuf *bufio.ReadWriter) {
+	if toWrite != nil {
+		if _, err := httpBuf.Write([]byte(toWrite.Error())); err != nil {
+			logrus.Errorf("Error writing error %q to container %s HTTP attach connection: %v", toWrite, cid, err)
+		} else if err := httpBuf.Flush(); err != nil {
+			logrus.Errorf("Error flushing HTTP buffer for container %s HTTP attach connection: %v", cid, err)
+		}
+	}
+
+	if err := httpCon.Close(); err != nil {
+		logrus.Errorf("Error closing container %s HTTP attach connection: %v", cid, err)
+	}
+}
diff --git a/pkg/api/handlers/containers_attach.go b/pkg/api/handlers/containers_attach.go
new file mode 100644
index 000000000..eb306348b
--- /dev/null
+++ b/pkg/api/handlers/containers_attach.go
@@ -0,0 +1,159 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/define"
+	"github.com/containers/libpod/pkg/api/handlers/utils"
+	"github.com/gorilla/mux"
+	"github.com/gorilla/schema"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+func AttachContainer(w http.ResponseWriter, r *http.Request) {
+	runtime := r.Context().Value("runtime").(*libpod.Runtime)
+	decoder := r.Context().Value("decoder").(*schema.Decoder)
+
+	query := struct {
+		DetachKeys string `schema:"detachKeys"`
+		Logs       bool   `schema:"logs"`
+		Stream     bool   `schema:"stream"`
+		Stdin      bool   `schema:"stdin"`
+		Stdout     bool   `schema:"stdout"`
+		Stderr     bool   `schema:"stderr"`
+	}{}
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
+		utils.Error(w, "Error parsing parameters", http.StatusBadRequest, err)
+		return
+	}
+
+	muxVars := mux.Vars(r)
+
+	// Detach keys: explicitly set to "" is very different from unset
+	// TODO: Our format for parsing these may be different from Docker.
+	var detachKeys *string
+	if _, found := muxVars["detachKeys"]; found {
+		detachKeys = &query.DetachKeys
+	}
+
+	streams := new(libpod.HTTPAttachStreams)
+	streams.Stdout = true
+	streams.Stderr = true
+	streams.Stdin = true
+	useStreams := false
+	if _, found := muxVars["stdin"]; found {
+		streams.Stdin = query.Stdin
+		useStreams = true
+	}
+	if _, found := muxVars["stdout"]; found {
+		streams.Stdout = query.Stdout
+		useStreams = true
+	}
+	if _, found := muxVars["stderr"]; found {
+		streams.Stderr = query.Stderr
+		useStreams = true
+	}
+	if !useStreams {
+		streams = nil
+	}
+	if useStreams && !streams.Stdout && !streams.Stderr && !streams.Stdin {
+		utils.Error(w, "Parameter conflict", http.StatusBadRequest, errors.Errorf("at least one of stdin, stdout, stderr must be true"))
+		return
+	}
+
+	// TODO: Investigate supporting these.
+	// Logs replays container logs over the attach socket.
+	// Stream seems to break things up somehow? Not 100% clear.
+	if query.Logs {
+		utils.Error(w, "Unsupported parameter", http.StatusBadRequest, errors.Errorf("the logs parameter to attach is not presently supported"))
+		return
+	}
+	// We only support stream=true or unset
+	if _, found := muxVars["stream"]; found && query.Stream {
+		utils.Error(w, "Unsupported parameter", http.StatusBadRequest, errors.Errorf("the stream parameter to attach is not presently supported"))
+		return
+	}
+
+	name := getName(r)
+	ctr, err := runtime.LookupContainer(name)
+	if err != nil {
+		utils.ContainerNotFound(w, name, err)
+		return
+	}
+
+	state, err := ctr.State()
+	if err != nil {
+		utils.InternalServerError(w, err)
+		return
+	}
+	if !(state == define.ContainerStateCreated || state == define.ContainerStateRunning) {
+		utils.InternalServerError(w, errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers"))
+		return
+	}
+
+	// Hijack the connection
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		utils.InternalServerError(w, errors.Errorf("unable to hijack connection"))
+		return
+	}
+
+	w.WriteHeader(http.StatusSwitchingProtocols)
+
+	connection, buffer, err := hijacker.Hijack()
+	if err != nil {
+		utils.InternalServerError(w, errors.Wrapf(err, "error hijacking connection"))
+		return
+	}
+
+	logrus.Debugf("Hijack for attach of container %s successful", ctr.ID())
+
+	// Perform HTTP attach.
+	// HTTPAttach will handle everything about the connection from here on
+	// (including closing it and writing errors to it).
+	if err := ctr.HTTPAttach(connection, buffer, streams, detachKeys, nil); err != nil {
+		// We can't really do anything about errors anymore. HTTPAttach
+		// should be writing them to the connection.
+		logrus.Errorf("Error attaching to container %s: %v", ctr.ID(), err)
+	}
+
+	logrus.Debugf("Attach for container %s completed successfully", ctr.ID())
+}
+
+func ResizeContainer(w http.ResponseWriter, r *http.Request) {
+	runtime := r.Context().Value("runtime").(*libpod.Runtime)
+	decoder := r.Context().Value("decoder").(*schema.Decoder)
+
+	query := struct {
+		Height uint16 `schema:"h"`
+		Width  uint16 `schema:"w"`
+	}{}
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
+		// This is not a 400, despite the fact that is should be, for
+		// compatibility reasons.
+		utils.InternalServerError(w, errors.Wrapf(err, "error parsing query options"))
+		return
+	}
+
+	name := getName(r)
+	ctr, err := runtime.LookupContainer(name)
+	if err != nil {
+		utils.ContainerNotFound(w, name, err)
+		return
+	}
+
+	newSize := remotecommand.TerminalSize{
+		Width:  query.Width,
+		Height: query.Height,
+	}
+	if err := ctr.AttachResize(newSize); err != nil {
+		utils.InternalServerError(w, err)
+		return
+	}
+	// This is not a 204, even though we write nothing, for compatibility
+	// reasons.
+	utils.WriteResponse(w, http.StatusOK, "")
+}
diff --git a/pkg/api/server/register_containers.go b/pkg/api/server/register_containers.go
index b275fa4d1..dbe194cd4 100644
--- a/pkg/api/server/register_containers.go
+++ b/pkg/api/server/register_containers.go
@@ -428,6 +428,91 @@ func (s *APIServer) RegisterContainersHandlers(r *mux.Router) error {
 	//   '500':
 	//      "$ref": "#/responses/InternalError"
 	r.HandleFunc(VersionedPath("/containers/{name:..*}/wait"), APIHandler(s.Context, generic.WaitContainer)).Methods(http.MethodPost)
+	// swagger:operation POST /containers/{nameOrID}/attach compat attach
+	// ---
+	// tags:
+	//   - containers (compat)
+	// summary: Attach to a container
+	// description: Hijacks the connection to forward the container's standard streams to the client.
+	// parameters:
+	//  - in: path
+	//    name: nameOrID
+	//    required: true
+	//    description: the name or ID of the container
+	//  - in: query
+	//    name: detachKeys
+	//    required: false
+	//    type: string
+	//    description: keys to use for detaching from the container
+	//  - in: query
+	//    name: logs
+	//    required: false
+	//    type: bool
+	//    description: Not yet supported
+	//  - in: query
+	//    name: stream
+	//    required: false
+	//    type: bool
+	//    default: true
+	//    description: If passed, must be set to true; stream=false is not yet supported
+	//  - in: query
+	//    name: stdout
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDOUT
+	//  - in: query
+	//    name: stderr
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDERR
+	//  - in: query
+	//    name: stdin
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDIN
+	// produces:
+	// - application/json
+	// responses:
+	//   '101':
+	//     description: No error, connection has been hijacked for transporting streams.
+	//   '400':
+	//       "$ref": "#/responses/BadParamError"
+	//   '404':
+	//       "$ref": "#/responses/NoSuchContainer"
+	//   '500':
+	//       "$ref": "#/responses/InternalError"
+	r.HandleFunc(VersionedPath("/containers/{name:..*}/attach"), APIHandler(s.Context, handlers.AttachContainer)).Methods(http.MethodPost)
+	// swagger:operation POST /containers/{nameOrID}/resize compat resize
+	// ---
+	// tags:
+	//  - containers (compat)
+	// summary: Resize a container's TTY
+	// description: Resize the terminal attached to a container (for use with Attach).
+	// parameters:
+	//  - in: path
+	//    name: nameOrID
+	//    required: true
+	//    description: the name or ID of the container
+	//  - in: query
+	//    name: h
+	//    type: int
+	//    required: false
+	//    description: Height to set for the terminal, in characters
+	//  - in: query
+	//    name: w
+	//    type: int
+	//    required: false
+	//    description: Width to set for the terminal, in characters
+	// produces:
+	// - application/json
+	// responses:
+	//   '200':
+	//        description: no error
+	//   '404':
+	//       "$ref": "#/responses/NoSuchContainer"
+	//   '500':
+	//       "$ref": "#/responses/InternalError"
+	r.HandleFunc(VersionedPath("/containers/{name:..*}/resize"), APIHandler(s.Context, handlers.ResizeContainer)).Methods(http.MethodPost)
 
 	/*
 		libpod endpoints
@@ -823,5 +908,90 @@ func (s *APIServer) RegisterContainersHandlers(r *mux.Router) error {
 	//   '500':
 	//      "$ref": "#/responses/InternalError"
 	r.HandleFunc(VersionedPath("/libpod/containers/{name:..*}/stop"), APIHandler(s.Context, handlers.StopContainer)).Methods(http.MethodPost)
+	// swagger:operation POST /libpod/containers/{nameOrID}/attach libpod attach
+	// ---
+	// tags:
+	//   - containers
+	// summary: Attach to a container
+	// description: Hijacks the connection to forward the container's standard streams to the client.
+	// parameters:
+	//  - in: path
+	//    name: nameOrID
+	//    required: true
+	//    description: the name or ID of the container
+	//  - in: query
+	//    name: detachKeys
+	//    required: false
+	//    type: string
+	//    description: keys to use for detaching from the container
+	//  - in: query
+	//    name: logs
+	//    required: false
+	//    type: bool
+	//    description: Not yet supported
+	//  - in: query
+	//    name: stream
+	//    required: false
+	//    type: bool
+	//    default: true
+	//    description: If passed, must be set to true; stream=false is not yet supported
+	//  - in: query
+	//    name: stdout
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDOUT
+	//  - in: query
+	//    name: stderr
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDERR
+	//  - in: query
+	//    name: stdin
+	//    required: false
+	//    type: bool
+	//    description: Attach to container STDIN
+	// produces:
+	// - application/json
+	// responses:
+	//   '101':
+	//     description: No error, connection has been hijacked for transporting streams.
+	//   '400':
+	//       "$ref": "#/responses/BadParamError"
+	//   '404':
+	//       "$ref": "#/responses/NoSuchContainer"
+	//   '500':
+	//       "$ref": "#/responses/InternalError"
+	r.HandleFunc(VersionedPath("/libpod/containers/{name:..*}/attach"), APIHandler(s.Context, handlers.AttachContainer)).Methods(http.MethodPost)
+	// swagger:operation POST /libpod/containers/{nameOrID}/resize libpod resize
+	// ---
+	// tags:
+	//  - containers
+	// summary: Resize a container's TTY
+	// description: Resize the terminal attached to a container (for use with Attach).
+	// parameters:
+	//  - in: path
+	//    name: nameOrID
+	//    required: true
+	//    description: the name or ID of the container
+	//  - in: query
+	//    name: h
+	//    type: int
+	//    required: false
+	//    description: Height to set for the terminal, in characters
+	//  - in: query
+	//    name: w
+	//    type: int
+	//    required: false
+	//    description: Width to set for the terminal, in characters
+	// produces:
+	// - application/json
+	// responses:
+	//   '200':
+	//        description: no error
+	//   '404':
+	//       "$ref": "#/responses/NoSuchContainer"
+	//   '500':
+	//       "$ref": "#/responses/InternalError"
+	r.HandleFunc(VersionedPath("/libpod/containers/{name:..*}/resize"), APIHandler(s.Context, handlers.ResizeContainer)).Methods(http.MethodPost)
 	return nil
 }
diff --git a/vendor/github.com/containers/conmon/LICENSE b/vendor/github.com/containers/conmon/LICENSE
new file mode 100644
index 000000000..28df615ce
--- /dev/null
+++ b/vendor/github.com/containers/conmon/LICENSE
@@ -0,0 +1,190 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   Copyright 2018-2019 github.com/containers authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/vendor/github.com/containers/conmon/runner/config/config.go b/vendor/github.com/containers/conmon/runner/config/config.go
new file mode 100644
index 000000000..cb70e9325
--- /dev/null
+++ b/vendor/github.com/containers/conmon/runner/config/config.go
@@ -0,0 +1,19 @@
+package config
+
+const (
+	// BufSize is the size of buffers passed in to sockets
+	BufSize = 8192
+	// ConnSockBufSize is the size of the socket used for
+	// to attach to the container
+	ConnSockBufSize = 32768
+	// WinResizeEvent is the event code the caller program will
+	// send along the ctrl fd to signal conmon to resize
+	// the pty window
+	WinResizeEvent = 1
+	// ReopenLogsEvent is the event code the caller program will
+	// send along the ctrl fd to signal conmon to reopen the log files
+	ReopenLogsEvent = 2
+	// TimedOutMessage is the message sent back to the caller by conmon
+	// when a container times out
+	TimedOutMessage = "command timed out"
+)
diff --git a/vendor/github.com/containers/conmon/runner/config/config_unix.go b/vendor/github.com/containers/conmon/runner/config/config_unix.go
new file mode 100644
index 000000000..5caaca7cc
--- /dev/null
+++ b/vendor/github.com/containers/conmon/runner/config/config_unix.go
@@ -0,0 +1,7 @@
+// +build !windows
+
+package config
+
+const (
+	ContainerAttachSocketDir = "/var/run/crio"
+)
diff --git a/vendor/github.com/containers/conmon/runner/config/config_windows.go b/vendor/github.com/containers/conmon/runner/config/config_windows.go
new file mode 100644
index 000000000..2161b9441
--- /dev/null
+++ b/vendor/github.com/containers/conmon/runner/config/config_windows.go
@@ -0,0 +1,7 @@
+// +build windows
+
+package config
+
+const (
+	ContainerAttachSocketDir = "C:\\crio\\run\\"
+)
diff --git a/vendor/modules.txt b/vendor/modules.txt
index fa01fbeec..ebac0089b 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -78,6 +78,8 @@ github.com/containers/buildah/util
 # github.com/containers/common v0.0.7
 github.com/containers/common/pkg/cgroups
 github.com/containers/common/pkg/unshare
+# github.com/containers/conmon v2.0.9+incompatible
+github.com/containers/conmon/runner/config
 # github.com/containers/image/v5 v5.1.0
 github.com/containers/image/v5/copy
 github.com/containers/image/v5/directory