Add default sandboxer to client

Signed-off-by: Derek McGowan <derek@mcg.dev>

client/client.go

@@ -114,7 +114,11 @@ func New(address string, opts ...Opt) (*Client, error) {
 	}
 
 	if copts.defaultRuntime != "" {
-		c.runtime.value = copts.defaultRuntime
+		c.defaults.runtime = copts.defaultRuntime
+	}
+
+	if copts.defaultSandboxer != "" {
+		c.defaults.sandboxer = copts.defaultSandboxer
 	}
 
 	if copts.defaultPlatform != nil {
@@ -190,7 +194,11 @@ func NewWithConn(conn *grpc.ClientConn, opts ...Opt) (*Client, error) {
 	}
 
 	if copts.defaultRuntime != "" {
-		c.runtime.value = copts.defaultRuntime
+		c.defaults.runtime = copts.defaultRuntime
+	}
+
+	if copts.defaultSandboxer != "" {
+		c.defaults.sandboxer = copts.defaultSandboxer
 	}
 
 	if copts.defaultPlatform != nil {
@@ -215,10 +223,11 @@ type Client struct {
 	platform  platforms.MatchComparer
 	connector func() (*grpc.ClientConn, error)
 
-	// this should only be accessed via defaultRuntime()
-	runtime struct {
-		value string
-		mut   sync.Mutex
+	// this should only be accessed via default*() functions
+	defaults struct {
+		runtime   string
+		sandboxer string
+		mut       sync.Mutex
 	}
 }
 
@@ -245,11 +254,11 @@ func (c *Client) Runtime() string {
 }
 
 func (c *Client) defaultRuntime(ctx context.Context) (string, error) {
-	c.runtime.mut.Lock()
-	defer c.runtime.mut.Unlock()
+	c.defaults.mut.Lock()
+	defer c.defaults.mut.Unlock()
 
-	if c.runtime.value != "" {
-		return c.runtime.value, nil
+	if c.defaults.runtime != "" {
+		return c.defaults.runtime, nil
 	}
 
 	if c.defaultns != "" {
@@ -259,12 +268,35 @@ func (c *Client) defaultRuntime(ctx context.Context) (string, error) {
 			return defaults.DefaultRuntime, fmt.Errorf("failed to get default runtime label: %w", err)
 		}
 		if label != "" {
-			c.runtime.value = label
+			c.defaults.runtime = label
 			return label, nil
 		}
 	}
-	c.runtime.value = defaults.DefaultRuntime
-	return c.runtime.value, nil
+	c.defaults.runtime = defaults.DefaultRuntime
+	return c.defaults.runtime, nil
+}
+
+func (c *Client) defaultSandboxer(ctx context.Context) (string, error) {
+	c.defaults.mut.Lock()
+	defer c.defaults.mut.Unlock()
+
+	if c.defaults.sandboxer != "" {
+		return c.defaults.sandboxer, nil
+	}
+
+	if c.defaultns != "" {
+		label, err := c.GetLabel(ctx, defaults.DefaultSandboxerNSLabel)
+		if err != nil {
+			// Don't set the sandboxer value if there's an error
+			return defaults.DefaultSandboxer, fmt.Errorf("failed to get default sandboxer label: %w", err)
+		}
+		if label != "" {
+			c.defaults.sandboxer = label
+			return label, nil
+		}
+	}
+	c.defaults.sandboxer = defaults.DefaultSandboxer
+	return c.defaults.sandboxer, nil
 }
 
 // IsServing returns true if the client can successfully connect to the

client/client_opts.go

@@ -30,14 +30,15 @@ import (
 )
 
 type clientOpts struct {
-	defaultns       string
-	defaultRuntime  string
-	defaultPlatform platforms.MatchComparer
-	services        *services
-	dialOptions     []grpc.DialOption
-	extraDialOpts   []grpc.DialOption
-	callOptions     []grpc.CallOption
-	timeout         time.Duration
+	defaultns        string
+	defaultRuntime   string
+	defaultSandboxer string
+	defaultPlatform  platforms.MatchComparer
+	services         *services
+	dialOptions      []grpc.DialOption
+	extraDialOpts    []grpc.DialOption
+	callOptions      []grpc.CallOption
+	timeout          time.Duration
 }
 
 // Opt allows callers to set options on the containerd client
@@ -62,6 +63,14 @@ func WithDefaultRuntime(rt string) Opt {
 	}
 }
 
+// WithDefaultSandboxer sets the default sandboxer on the client
+func WithDefaultSandboxer(sb string) Opt {
+	return func(c *clientOpts) error {
+		c.defaultSandboxer = sb
+		return nil
+	}
+}
+
 // WithDefaultPlatform sets the default platform matcher on the client
 func WithDefaultPlatform(platform platforms.MatchComparer) Opt {
 	return func(c *clientOpts) error {

client/sandbox.go

@@ -131,10 +131,15 @@ func (c *Client) NewSandbox(ctx context.Context, sandboxID string, opts ...NewSa
 		return nil, errors.New("sandbox ID must be specified")
 	}
 
+	sandboxer, err := c.defaultSandboxer(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get default sandboxer: %w", err)
+	}
 	newSandbox := api.Sandbox{
 		ID:        sandboxID,
 		CreatedAt: time.Now().UTC(),
 		UpdatedAt: time.Now().UTC(),
+		Sandboxer: sandboxer,
 	}
 
 	for _, opt := range opts {

defaults/defaults.go

@@ -29,4 +29,9 @@ const (
 	// DefaultSnapshotterNSLabel defines the namespace label to check for the
 	// default snapshotter
 	DefaultSnapshotterNSLabel = "containerd.io/defaults/snapshotter"
+	// DefaultSandboxerNSLabel defines the namespace label to check for the
+	// default sandboxcr
+	DefaultSandboxerNSLabel = "containerd.io/defaults/sandboxer"
+	// DefaultSandboxer defines the default sandboxer to use for creating sandboxes.
+	DefaultSandboxer = "shim"
 )