Removing old custom RootFS behavior on Windows.

Windows base layers are no longer the special "layers+base" type, so we can remove all the special handling for that.

Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>

daemon/daemon_windows.go

@@ -426,9 +426,8 @@ func rootFSToAPIType(rootfs *image.RootFS) types.RootFS {
 		layers = append(layers, l.String())
 	}
 	return types.RootFS{
-		Type:      rootfs.Type,
-		Layers:    layers,
-		BaseLayer: rootfs.BaseLayer,
+		Type:   rootfs.Type,
+		Layers: layers,
 	}
 }
 

daemon/oci_windows.go

@@ -89,15 +89,10 @@ func (daemon *Daemon) createSpec(c *container.Container) (*libcontainerd.Spec, e
 
 	// s.Windows.LayerPaths
 	var layerPaths []string
-	if img.RootFS != nil && (img.RootFS.Type == image.TypeLayers || img.RootFS.Type == image.TypeLayersWithBase) {
+	if img.RootFS != nil && img.RootFS.Type == image.TypeLayers {
 		// Get the layer path for each layer.
-		start := 1
-		if img.RootFS.Type == image.TypeLayersWithBase {
-			// Include an empty slice to get the base layer ID.
-			start = 0
-		}
 		max := len(img.RootFS.DiffIDs)
-		for i := start; i <= max; i++ {
+		for i := 1; i <= max; i++ {
 			img.RootFS.DiffIDs = img.RootFS.DiffIDs[:i]
 			path, err := layer.GetLayerPath(daemon.layerStore, img.RootFS.ChainID())
 			if err != nil {

distribution/pull_v2.go

@@ -423,10 +423,6 @@ func (p *v2Puller) pullSchema1(ctx context.Context, ref reference.Named, unverif
 
 	rootFS := image.NewRootFS()
 
-	if err := detectBaseLayer(p.config.ImageStore, verifiedManifest, rootFS); err != nil {
-		return "", "", err
-	}
-
 	// remove duplicate layers and check parent chain validity
 	err = fixManifestLayers(verifiedManifest)
 	if err != nil {
@@ -542,25 +538,15 @@ func (p *v2Puller) pullSchema2(ctx context.Context, ref reference.Named, mfst *s
 		unmarshalledConfig image.Image  // deserialized image config
 		downloadRootFS     image.RootFS // rootFS to use for registering layers.
 	)
-	if runtime.GOOS == "windows" {
-		configJSON, unmarshalledConfig, err = receiveConfig(configChan, errChan)
-		if err != nil {
-			return "", "", err
-		}
-		if unmarshalledConfig.RootFS == nil {
-			return "", "", errors.New("image config has no rootfs section")
-		}
-		// https://github.com/docker/docker/issues/24766 - Err on the side of caution,
-		// explicitly blocking images intended for linux from the Windows daemon
-		if unmarshalledConfig.OS == "linux" {
-			return "", "", fmt.Errorf("image operating system %q cannot be used on this platform", unmarshalledConfig.OS)
-		}
-		downloadRootFS = *unmarshalledConfig.RootFS
-		downloadRootFS.DiffIDs = []layer.DiffID{}
-	} else {
-		downloadRootFS = *image.NewRootFS()
+
+	// https://github.com/docker/docker/issues/24766 - Err on the side of caution,
+	// explicitly blocking images intended for linux from the Windows daemon
+	if runtime.GOOS == "windows" && unmarshalledConfig.OS == "linux" {
+		return "", "", fmt.Errorf("image operating system %q cannot be used on this platform", unmarshalledConfig.OS)
 	}
 
+	downloadRootFS = *image.NewRootFS()
+
 	rootFS, release, err := p.config.DownloadManager.Download(ctx, downloadRootFS, descriptors, p.config.ProgressOutput)
 	if err != nil {
 		if configJSON != nil {

distribution/pull_v2_unix.go

@@ -5,14 +5,8 @@ package distribution
 import (
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
-	"github.com/docker/distribution/manifest/schema1"
-	"github.com/docker/docker/image"
 )
 
-func detectBaseLayer(is image.Store, m *schema1.Manifest, rootFS *image.RootFS) error {
-	return nil
-}
-
 func (ld *v2LayerDescriptor) open(ctx context.Context) (distribution.ReadSeekCloser, error) {
 	blobs := ld.repo.Blobs(ctx)
 	return blobs.Open(ctx, ld.digest)

distribution/pull_v2_windows.go

@@ -3,38 +3,15 @@
 package distribution
 
 import (
-	"encoding/json"
-	"fmt"
 	"net/http"
 	"os"
 
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
-	"github.com/docker/distribution/manifest/schema1"
 	"github.com/docker/distribution/manifest/schema2"
 	"github.com/docker/distribution/registry/client/transport"
-	"github.com/docker/docker/image"
 )
 
-func detectBaseLayer(is image.Store, m *schema1.Manifest, rootFS *image.RootFS) error {
-	v1img := &image.V1Image{}
-	if err := json.Unmarshal([]byte(m.History[len(m.History)-1].V1Compatibility), v1img); err != nil {
-		return err
-	}
-	if v1img.Parent == "" {
-		return fmt.Errorf("Last layer %q does not have a base layer reference", v1img.ID)
-	}
-	// There must be an image that already references the baselayer.
-	for _, img := range is.Map() {
-		if img.RootFS.Type == image.TypeLayersWithBase && img.RootFS.BaseLayerID() == v1img.Parent {
-			rootFS.BaseLayer = img.RootFS.BaseLayer
-			rootFS.Type = image.TypeLayersWithBase
-			return nil
-		}
-	}
-	return fmt.Errorf("Invalid base layer %q", v1img.Parent)
-}
-
 var _ distribution.Describable = &v2LayerDescriptor{}
 
 func (ld *v2LayerDescriptor) Descriptor() distribution.Descriptor {

image/rootfs.go

@@ -5,6 +5,14 @@ import "github.com/docker/docker/layer"
 // TypeLayers is used for RootFS.Type for filesystems organized into layers.
 const TypeLayers = "layers"
 
+// RootFS describes images root filesystem
+// This is currently a placeholder that only supports layers. In the future
+// this can be made into an interface that supports different implementations.
+type RootFS struct {
+	Type    string         `json:"type"`
+	DiffIDs []layer.DiffID `json:"diff_ids,omitempty"`
+}
+
 // NewRootFS returns empty RootFS struct
 func NewRootFS() *RootFS {
 	return &RootFS{Type: TypeLayers}
@@ -14,3 +22,8 @@ func NewRootFS() *RootFS {
 func (r *RootFS) Append(id layer.DiffID) {
 	r.DiffIDs = append(r.DiffIDs, id)
 }
+
+// ChainID returns the ChainID for the top layer in RootFS.
+func (r *RootFS) ChainID() layer.ChainID {
+	return layer.CreateChainID(r.DiffIDs)
+}

image/rootfs_unix.go

@@ -1,18 +0,0 @@
-// +build !windows
-
-package image
-
-import "github.com/docker/docker/layer"
-
-// RootFS describes images root filesystem
-// This is currently a placeholder that only supports layers. In the future
-// this can be made into an interface that supports different implementations.
-type RootFS struct {
-	Type    string         `json:"type"`
-	DiffIDs []layer.DiffID `json:"diff_ids,omitempty"`
-}
-
-// ChainID returns the ChainID for the top layer in RootFS.
-func (r *RootFS) ChainID() layer.ChainID {
-	return layer.CreateChainID(r.DiffIDs)
-}

image/rootfs_windows.go

@@ -1,48 +0,0 @@
-// +build windows
-
-package image
-
-import (
-	"crypto/sha512"
-	"fmt"
-
-	"github.com/docker/distribution/digest"
-	"github.com/docker/docker/layer"
-)
-
-// TypeLayersWithBase is used for RootFS.Type for Windows filesystems that have layers and a centrally-stored base layer.
-const TypeLayersWithBase = "layers+base"
-
-// RootFS describes images root filesystem
-// This is currently a placeholder that only supports layers. In the future
-// this can be made into an interface that supports different implementations.
-type RootFS struct {
-	Type      string         `json:"type"`
-	DiffIDs   []layer.DiffID `json:"diff_ids,omitempty"`
-	BaseLayer string         `json:"base_layer,omitempty"`
-}
-
-// BaseLayerID returns the 64 byte hex ID for the baselayer name.
-func (r *RootFS) BaseLayerID() string {
-	if r.Type != TypeLayersWithBase {
-		panic("tried to get base layer ID without a base layer")
-	}
-	baseID := sha512.Sum384([]byte(r.BaseLayer))
-	return fmt.Sprintf("%x", baseID[:32])
-}
-
-// ChainID returns the ChainID for the top layer in RootFS.
-func (r *RootFS) ChainID() layer.ChainID {
-	ids := r.DiffIDs
-	if r.Type == TypeLayersWithBase {
-		// Add an extra ID for the base.
-		baseDiffID := layer.DiffID(digest.FromBytes([]byte(r.BaseLayerID())))
-		ids = append([]layer.DiffID{baseDiffID}, ids...)
-	}
-	return layer.CreateChainID(ids)
-}
-
-// NewRootFSWithBaseLayer returns a RootFS struct with a base layer
-func NewRootFSWithBaseLayer(baseLayer string) *RootFS {
-	return &RootFS{Type: TypeLayersWithBase, BaseLayer: baseLayer}
-}

image/spec/v1.1.md

@@ -370,10 +370,7 @@ whitespace. It has been added to this example for clarity.
 
         <ul>
           <li>
-            <code>type</code> is usually set to <code>layers</code>. There is
-            also a Windows-specific value <code>layers+base</code> that allows
-            a base layer to be specified in a field of <code>rootfs</code>
-            called <code>base_layer</code>.
+            <code>type</code> is usually set to <code>layers</code>.
           </li>
           <li>
             <code>diff_ids</code> is an array of layer content hashes (<code>DiffIDs</code>), in order from bottom-most to top-most.