Merge pull request #838 from mlaventure/allow-specifying-shim

Allow specifying shim

cmd/ctr/run_unix.go

@@ -27,7 +27,7 @@ import (
 
 const (
 	rwm               = "rwm"
-	rootfsPath = "rootfs"
+	defaultRootfsPath = "rootfs"
 )
 
 var capabilities = []string{
@@ -47,7 +47,7 @@ var capabilities = []string{
 	"CAP_AUDIT_WRITE",
 }
 
-func spec(id string, config *ocispec.ImageConfig, context *cli.Context) (*specs.Spec, error) {
+func spec(id string, config *ocispec.ImageConfig, context *cli.Context, rootfs string) (*specs.Spec, error) {
 	env := []string{
 		"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
 	}
@@ -92,6 +92,9 @@ func spec(id string, config *ocispec.ImageConfig, context *cli.Context) (*specs.
 	if cwd == "" {
 		cwd = "/"
 	}
+	if rootfs == "" {
+		rootfs = defaultRootfsPath
+	}
 	s := &specs.Spec{
 		Version: specs.Version,
 		Platform: specs.Platform{
@@ -99,7 +102,7 @@ func spec(id string, config *ocispec.ImageConfig, context *cli.Context) (*specs.
 			Arch: runtime.GOARCH,
 		},
 		Root: specs.Root{
-			Path:     rootfsPath,
+			Path:     rootfs,
 			Readonly: context.Bool("readonly"),
 		},
 		Process: specs.Process{
@@ -232,9 +235,9 @@ func customSpec(configPath string, rootfs string) (*specs.Spec, error) {
 		return nil, err
 	}
 	if rootfs == "" {
-		if s.Root.Path != rootfsPath {
+		if s.Root.Path != defaultRootfsPath {
-			logrus.Warnf("ignoring Root.Path %q, setting %q forcibly", s.Root.Path, rootfsPath)
+			logrus.Warnf("ignoring Root.Path %q, setting %q forcibly", s.Root.Path, defaultRootfsPath)
-			s.Root.Path = rootfsPath
+			s.Root.Path = defaultRootfsPath
 		}
 	} else {
 		s.Root.Path = rootfs
@@ -245,7 +248,7 @@ func customSpec(configPath string, rootfs string) (*specs.Spec, error) {
 func getConfig(context *cli.Context, imageConfig *ocispec.ImageConfig, rootfs string) (*specs.Spec, error) {
 	config := context.String("runtime-config")
 	if config == "" {
-		return spec(context.String("id"), imageConfig, context)
+		return spec(context.String("id"), imageConfig, context, rootfs)
 	}
 
 	return customSpec(config, rootfs)

linux/runtime.go

@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/containerd/containerd"
@@ -27,23 +28,29 @@ const (
 	runtimeName    = "linux"
 	configFilename = "config.json"
 	defaultRuntime = "runc"
+	defaultShim    = "containerd-shim"
 )
 
 func init() {
 	plugin.Register(runtimeName, &plugin.Registration{
 		Type: plugin.RuntimePlugin,
 		Init: New,
-		Config: &Config{},
+		Config: &Config{
+			Shim:    defaultShim,
+			Runtime: defaultRuntime,
+		},
 	})
 }
 
 var _ = (plugin.Runtime)(&Runtime{})
 
 type Config struct {
+	// Shim is a path or name of binary implementing the Shim GRPC API
+	Shim string `toml:"shim,omitempty"`
 	// Runtime is a path or name of an OCI runtime used by the shim
-	Runtime string `toml:"runtime"`
+	Runtime string `toml:"runtime,omitempty"`
 	// NoShim calls runc directly from within the pkg
-	NoShim bool `toml:"no_shim"`
+	NoShim bool `toml:"no_shim,omitempty"`
 }
 
 func New(ic *plugin.InitContext) (interface{}, error) {
@@ -52,13 +59,11 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 		return nil, err
 	}
 	cfg := ic.Config.(*Config)
-	if cfg.Runtime == "" {
-		cfg.Runtime = defaultRuntime
-	}
 	c, cancel := context.WithCancel(ic.Context)
 	r := &Runtime{
 		root:          path,
 		remote:        !cfg.NoShim,
+		shim:          cfg.Shim,
 		runtime:       cfg.Runtime,
 		events:        make(chan *containerd.Event, 2048),
 		eventsContext: c,
@@ -72,6 +77,7 @@ func New(ic *plugin.InitContext) (interface{}, error) {
 
 type Runtime struct {
 	root    string
+	shim    string
 	runtime string
 	remote  bool
 
@@ -86,7 +92,7 @@ func (r *Runtime) Create(ctx context.Context, id string, opts plugin.CreateOpts)
 	if err != nil {
 		return nil, err
 	}
-	s, err := newShim(path, r.remote)
+	s, err := newShim(r.shim, path, r.remote)
 	if err != nil {
 		os.RemoveAll(path)
 		return nil, err
@@ -187,7 +193,9 @@ func (r *Runtime) forward(events shim.Shim_EventsClient) {
 	for {
 		e, err := events.Recv()
 		if err != nil {
+			if !strings.HasSuffix(err.Error(), "transport is closing") {
 				log.G(r.eventsContext).WithError(err).Error("get event from shim")
+			}
 			return
 		}
 		var et containerd.EventType

linux/shim.go

@@ -22,7 +22,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-func newShim(path string, remote bool) (shim.ShimClient, error) {
+func newShim(shimName string, path string, remote bool) (shim.ShimClient, error) {
 	if !remote {
 		return localShim.Client(path)
 	}
@@ -31,7 +31,7 @@ func newShim(path string, remote bool) (shim.ShimClient, error) {
 	if err != nil {
 		return nil, err
 	}
-	cmd := exec.Command("containerd-shim")
+	cmd := exec.Command(shimName)
 	cmd.Dir = path
 	f, err := l.(*net.UnixListener).File()
 	if err != nil {