Take default runtime and snapshotter from namespace labels

Signed-off-by: Nikhil Soni <krsoninikhil@gmail.com>

client.go

@@ -138,6 +138,22 @@ func New(address string, opts ...ClientOpt) (*Client, error) {
 	if copts.services == nil && c.conn == nil {
 		return nil, errors.New("no grpc connection or services is available")
 	}
+
+	// check namespace labels for default runtime
+	defaultns := "default"
+	if copts.defaultns != "" {
+		defaultns = copts.defaultns
+	}
+	namespaces := c.NamespaceService()
+	ctx := context.Background()
+	if labels, err := namespaces.Labels(ctx, defaultns); err == nil {
+		if defaultRuntime, ok := labels["runtime"]; ok {
+			c.runtime = defaultRuntime
+		}
+	} else {
+		return nil, err
+	}
+
 	return c, nil
 }
 

client_test.go

@@ -393,3 +393,28 @@ func createShimDebugConfig() string {
 
 	return f.Name()
 }
+
+func TestDefaultRuntimeWithNamespaceLabels(t *testing.T) {
+	client, err := newClient(t, address)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer client.Close()
+
+	ctx, cancel := testContext()
+	defer cancel()
+	namespaces := client.NamespaceService()
+	testRuntime := "testRuntime"
+	if err := namespaces.SetLabel(ctx, testNamespace, "runtime", testRuntime); err != nil {
+		t.Fatal(err)
+	}
+
+	testClient, err := newClient(t, address, WithDefaultNamespace(testNamespace))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testClient.Close()
+	if testClient.runtime != testRuntime {
+		t.Error("failed to set default runtime from namespace labels")
+	}
+}

container_opts.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/errdefs"
+	"github.com/containerd/containerd/namespaces"
 	"github.com/containerd/containerd/oci"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/typeurl"
@@ -106,7 +107,7 @@ func WithSnapshotter(name string) NewContainerOpts {
 // WithSnapshot uses an existing root filesystem for the container
 func WithSnapshot(id string) NewContainerOpts {
 	return func(ctx context.Context, client *Client, c *containers.Container) error {
-		setSnapshotterIfEmpty(c)
+		setSnapshotterIfEmpty(ctx, client, c)
 		// check that the snapshot exists, if not, fail on creation
 		if _, err := client.SnapshotService(c.Snapshotter).Mounts(ctx, id); err != nil {
 			return err
@@ -124,7 +125,7 @@ func WithNewSnapshot(id string, i Image) NewContainerOpts {
 		if err != nil {
 			return err
 		}
-		setSnapshotterIfEmpty(c)
+		setSnapshotterIfEmpty(ctx, client, c)
 		parent := identity.ChainID(diffIDs).String()
 		if _, err := client.SnapshotService(c.Snapshotter).Prepare(ctx, id, parent); err != nil {
 			return err
@@ -154,7 +155,7 @@ func WithNewSnapshotView(id string, i Image) NewContainerOpts {
 		if err != nil {
 			return err
 		}
-		setSnapshotterIfEmpty(c)
+		setSnapshotterIfEmpty(ctx, client, c)
 		parent := identity.ChainID(diffIDs).String()
 		if _, err := client.SnapshotService(c.Snapshotter).View(ctx, id, parent); err != nil {
 			return err
@@ -165,9 +166,18 @@ func WithNewSnapshotView(id string, i Image) NewContainerOpts {
 	}
 }
 
-func setSnapshotterIfEmpty(c *containers.Container) {
+func setSnapshotterIfEmpty(ctx context.Context, client *Client, c *containers.Container) {
 	if c.Snapshotter == "" {
-		c.Snapshotter = DefaultSnapshotter
+		defaultSnapshotter := DefaultSnapshotter
+		namespaceService := client.NamespaceService()
+		if ns, err := namespaces.NamespaceRequired(ctx); err == nil {
+			if labels, err := namespaceService.Labels(ctx, ns); err == nil {
+				if snapshotLabel, ok := labels["snapshotter"]; ok {
+					defaultSnapshotter = snapshotLabel
+				}
+			}
+		}
+		c.Snapshotter = defaultSnapshotter
 	}
 }
 

container_opts_unix.go

@@ -50,7 +50,7 @@ func withRemappedSnapshotBase(id string, i Image, uid, gid uint32, readonly bool
 			return err
 		}
 
-		setSnapshotterIfEmpty(c)
+		setSnapshotterIfEmpty(ctx, client, c)
 
 		var (
 			snapshotter = client.SnapshotService(c.Snapshotter)