Wire in endpoint for ExecStart

This is still very early not not well tested, and missing resize
capability, but it does provide the first bits of exec.

Signed-off-by: Matthew Heon <mheon@redhat.com>

pkg/api/handlers/compat/containers_attach.go

@@ -13,6 +13,12 @@ import (
 	"k8s.io/client-go/tools/remotecommand"
 )
 
+// AttachHeader is the literal header sent for upgraded/hijacked connections for
+// attach, sourced from Docker at:
+// https://raw.githubusercontent.com/moby/moby/b95fad8e51bd064be4f4e58a996924f343846c85/api/server/router/container/container_routes.go
+// Using literally to ensure compatibility with existing clients.
+const AttachHeader = "HTTP/1.1 101 UPGRADED\r\nContent-Type: application/vnd.docker.raw-stream\r\nConnection: Upgrade\r\nUpgrade: tcp\r\n\r\n"
+
 func AttachContainer(w http.ResponseWriter, r *http.Request) {
 	runtime := r.Context().Value("runtime").(*libpod.Runtime)
 	decoder := r.Context().Value("decoder").(*schema.Decoder)
@@ -106,10 +112,7 @@ func AttachContainer(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// This header string sourced from Docker:
-	// https://raw.githubusercontent.com/moby/moby/b95fad8e51bd064be4f4e58a996924f343846c85/api/server/router/container/container_routes.go
-	// Using literally to ensure compatibility with existing clients.
-	fmt.Fprintf(connection, "HTTP/1.1 101 UPGRADED\r\nContent-Type: application/vnd.docker.raw-stream\r\nConnection: Upgrade\r\nUpgrade: tcp\r\n\r\n")
+	fmt.Fprintf(connection, AttachHeader)
 
 	logrus.Debugf("Hijack for attach of container %s successful", ctr.ID())
 

pkg/api/handlers/compat/exec.go

@@ -11,6 +11,7 @@ import (
 	"github.com/containers/libpod/pkg/api/handlers"
 	"github.com/containers/libpod/pkg/api/handlers/utils"
 	"github.com/gorilla/mux"
+	"github.com/gorilla/schema"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
@@ -105,3 +106,76 @@ func ExecInspectHandler(w http.ResponseWriter, r *http.Request) {
 
 	utils.WriteResponse(w, http.StatusOK, inspectOut)
 }
+
+// ExecStartHandler runs a given exec session.
+func ExecStartHandler(w http.ResponseWriter, r *http.Request) {
+	runtime := r.Context().Value("runtime").(*libpod.Runtime)
+	decoder := r.Context().Value("decoder").(*schema.Decoder)
+
+	sessionID := mux.Vars(r)["id"]
+
+	// TODO: Need to support these
+	query := struct {
+		Detach bool `schema:"Detach"`
+		Tty    bool `schema:"Tty"`
+	}{
+		// override any golang type defaults
+	}
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
+		utils.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest,
+			errors.Wrapf(err, "Failed to parse parameters for %s", r.URL.String()))
+		return
+	}
+
+	if _, found := r.URL.Query()["Detach"]; found {
+		utils.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest,
+			errors.Errorf("Detached exec is not yet supported"))
+		return
+	}
+	if _, found := r.URL.Query()["Tty"]; found {
+		utils.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest,
+			errors.Errorf("overriding terminal setting in ExecStart is not yet supported"))
+		return
+	}
+
+	sessionCtr, err := runtime.GetExecSessionContainer(sessionID)
+	if err != nil {
+		utils.Error(w, fmt.Sprintf("No such exec session: %s", sessionID), http.StatusNotFound, err)
+		return
+	}
+
+	logrus.Debugf("Starting exec session %s of container %s", sessionID, sessionCtr.ID())
+
+	state, err := sessionCtr.State()
+	if err != nil {
+		utils.InternalServerError(w, err)
+		return
+	}
+	if state != define.ContainerStateRunning {
+		utils.Error(w, http.StatusText(http.StatusConflict), http.StatusConflict, errors.Errorf("cannot exec in a container that is not running; container %s is %s", sessionCtr.ID(), state.String()))
+		return
+	}
+
+	// Hijack the connection
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		utils.InternalServerError(w, errors.Errorf("unable to hijack connection"))
+		return
+	}
+
+	connection, buffer, err := hijacker.Hijack()
+	if err != nil {
+		utils.InternalServerError(w, errors.Wrapf(err, "error hijacking connection"))
+		return
+	}
+
+	fmt.Fprintf(connection, AttachHeader)
+
+	logrus.Debugf("Hijack for attach of container %s exec session %s successful", sessionCtr.ID(), sessionID)
+
+	if err := sessionCtr.ExecHTTPStartAndAttach(sessionID, connection, buffer, nil, nil, nil); err != nil {
+		logrus.Errorf("Error attaching to container %s exec session %s: %v", sessionCtr.ID(), sessionID, err)
+	}
+
+	logrus.Debugf("Attach for container %s exec session %s completed successfully", sessionCtr.ID(), sessionID)
+}

pkg/api/server/register_exec.go

@@ -97,10 +97,10 @@ func (s *APIServer) registerExecHandlers(r *mux.Router) error {
 	//      properties:
 	//        Detach:
 	//          type: boolean
-	//          description: Detach from the command
+	//          description: Detach from the command. Not presently supported.
 	//        Tty:
 	//          type: boolean
-	//          description: Allocate a pseudo-TTY
+	//          description: Allocate a pseudo-TTY. Not presently supported.
 	// produces:
 	// - application/json
 	// responses:
@@ -109,10 +109,10 @@ func (s *APIServer) registerExecHandlers(r *mux.Router) error {
 	//   404:
 	//     $ref: "#/responses/NoSuchExecInstance"
 	//   409:
-	//	   description: container is stopped or paused
+	//	   description: container is not running
 	//   500:
 	//     $ref: "#/responses/InternalError"
-	r.Handle(VersionedPath("/exec/{id}/start"), s.APIHandler(compat.UnsupportedHandler)).Methods(http.MethodPost)
+	r.Handle(VersionedPath("/exec/{id}/start"), s.APIHandler(compat.ExecStartHandler)).Methods(http.MethodPost)
 	// Added non version path to URI to support docker non versioned paths
 	r.Handle("/exec/{id}/start", s.APIHandler(compat.UnsupportedHandler)).Methods(http.MethodPost)
 	// swagger:operation POST /exec/{id}/resize compat resizeExec