store: new API ApplyStagedLayer

drivers/driver.go

@@ -249,8 +249,8 @@ type DriverWithDiffer interface {
 	// ApplyDiffWithDiffer applies the changes using the callback function.
 	// If id is empty, then a staging directory is created.  The staging directory is guaranteed to be usable with ApplyDiffFromStagingDirectory.
 	ApplyDiffWithDiffer(id, parent string, options *ApplyDiffWithDifferOpts, differ Differ) (output DriverWithDifferOutput, err error)
-	// ApplyDiffFromStagingDirectory applies the changes using the specified staging directory.
-	ApplyDiffFromStagingDirectory(id, parent, stagingDirectory string, diffOutput *DriverWithDifferOutput, options *ApplyDiffWithDifferOpts) error
+	// ApplyDiffFromStagingDirectory applies the changes using the diffOutput target directory.
+	ApplyDiffFromStagingDirectory(id, parent string, diffOutput *DriverWithDifferOutput, options *ApplyDiffWithDifferOpts) error
 	// CleanupStagingDirectory cleanups the staging directory.  It can be used to cleanup the staging directory on errors
 	CleanupStagingDirectory(stagingDirectory string) error
 	// DifferTarget gets the location where files are stored for the layer.

drivers/overlay/overlay.go

@@ -2124,7 +2124,8 @@ func (d *Driver) ApplyDiffWithDiffer(id, parent string, options *graphdriver.App
 }
 
 // ApplyDiffFromStagingDirectory applies the changes using the specified staging directory.
-func (d *Driver) ApplyDiffFromStagingDirectory(id, parent, stagingDirectory string, diffOutput *graphdriver.DriverWithDifferOutput, options *graphdriver.ApplyDiffWithDifferOpts) error {
+func (d *Driver) ApplyDiffFromStagingDirectory(id, parent string, diffOutput *graphdriver.DriverWithDifferOutput, options *graphdriver.ApplyDiffWithDifferOpts) error {
+	stagingDirectory := diffOutput.Target
 	if filepath.Dir(stagingDirectory) != d.getStagingDir() {
 		return fmt.Errorf("%q is not a staging directory", stagingDirectory)
 	}

layers.go

@@ -181,6 +181,13 @@ type DiffOptions struct {
 	Compression *archive.Compression
 }
 
+// stagedLayerOptions are the options passed to .create to populate a staged
+// layer
+type stagedLayerOptions struct {
+	DiffOutput  *drivers.DriverWithDifferOutput
+	DiffOptions *drivers.ApplyDiffWithDifferOpts
+}
+
 // roLayerStore wraps a graph driver, adding the ability to refer to layers by
 // name, and keeping track of parent-child relationships, along with a list of
 // all known layers.
@@ -267,7 +274,7 @@ type rwLayerStore interface {
 	// underlying drivers do not themselves distinguish between writeable
 	// and read-only layers.  Returns the new layer structure and the size of the
 	// diff which was applied to its parent to initialize its contents.
-	create(id string, parent *Layer, names []string, mountLabel string, options map[string]string, moreOptions *LayerOptions, writeable bool, diff io.Reader) (*Layer, int64, error)
+	create(id string, parent *Layer, names []string, mountLabel string, options map[string]string, moreOptions *LayerOptions, writeable bool, diff io.Reader, slo *stagedLayerOptions) (*Layer, int64, error)
 
 	// updateNames modifies names associated with a layer based on (op, names).
 	updateNames(id string, names []string, op updateNameOperation) error
@@ -312,8 +319,8 @@ type rwLayerStore interface {
 	// CleanupStagingDirectory cleanups the staging directory.  It can be used to cleanup the staging directory on errors
 	CleanupStagingDirectory(stagingDirectory string) error
 
-	// ApplyDiffFromStagingDirectory uses stagingDirectory to create the diff.
-	ApplyDiffFromStagingDirectory(id, stagingDirectory string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error
+	// applyDiffFromStagingDirectory uses diffOutput.Target to create the diff.
+	applyDiffFromStagingDirectory(id string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error
 
 	// DifferTarget gets the location where files are stored for the layer.
 	DifferTarget(id string) (string, error)
@@ -1232,7 +1239,7 @@ func (r *layerStore) PutAdditionalLayer(id string, parentLayer *Layer, names []s
 }
 
 // Requires startWriting.
-func (r *layerStore) create(id string, parentLayer *Layer, names []string, mountLabel string, options map[string]string, moreOptions *LayerOptions, writeable bool, diff io.Reader) (layer *Layer, size int64, err error) {
+func (r *layerStore) create(id string, parentLayer *Layer, names []string, mountLabel string, options map[string]string, moreOptions *LayerOptions, writeable bool, diff io.Reader, slo *stagedLayerOptions) (layer *Layer, size int64, err error) {
 	if moreOptions == nil {
 		moreOptions = &LayerOptions{}
 	}
@@ -1426,6 +1433,11 @@ func (r *layerStore) create(id string, parentLayer *Layer, names []string, mount
 			cleanupFailureContext = "applying layer diff"
 			return nil, -1, err
 		}
+	} else if slo != nil {
+		if err := r.applyDiffFromStagingDirectory(layer.ID, slo.DiffOutput, slo.DiffOptions); err != nil {
+			cleanupFailureContext = "applying staged directory diff"
+			return nil, -1, err
+		}
 	} else {
 		// applyDiffWithOptions() would have updated r.bycompressedsum
 		// and r.byuncompressedsum for us, but if we used a template
@@ -2414,7 +2426,7 @@ func (r *layerStore) DifferTarget(id string) (string, error) {
 }
 
 // Requires startWriting.
-func (r *layerStore) ApplyDiffFromStagingDirectory(id, stagingDirectory string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error {
+func (r *layerStore) applyDiffFromStagingDirectory(id string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error {
 	ddriver, ok := r.driver.(drivers.DriverWithDiffer)
 	if !ok {
 		return ErrNotSupported
@@ -2433,7 +2445,7 @@ func (r *layerStore) ApplyDiffFromStagingDirectory(id, stagingDirectory string,
 		}
 	}
 
-	err := ddriver.ApplyDiffFromStagingDirectory(layer.ID, layer.Parent, stagingDirectory, diffOutput, options)
+	err := ddriver.ApplyDiffFromStagingDirectory(layer.ID, layer.Parent, diffOutput, options)
 	if err != nil {
 		return err
 	}

store.go

@@ -71,6 +71,19 @@ type metadataStore interface {
 	rwMetadataStore
 }
 
+// ApplyStagedLayerOptions contains options to pass to ApplyStagedLayer
+type ApplyStagedLayerOptions struct {
+	ID           string        // Mandatory
+	ParentLayer  string        // Optional
+	Names        []string      // Optional
+	MountLabel   string        // Optional
+	Writeable    bool          // Optional
+	LayerOptions *LayerOptions // Optional
+
+	DiffOutput  *drivers.DriverWithDifferOutput  // Mandatory
+	DiffOptions *drivers.ApplyDiffWithDifferOpts // Mandatory
+}
+
 // An roBigDataStore wraps up the read-only big-data related methods of the
 // various types of file-based lookaside stores that we implement.
 type roBigDataStore interface {
@@ -318,11 +331,21 @@ type Store interface {
 	ApplyDiffWithDiffer(to string, options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error)
 
 	// ApplyDiffFromStagingDirectory uses stagingDirectory to create the diff.
+	// Deprecated: it will be removed soon.  Use ApplyStagedLayer instead.
 	ApplyDiffFromStagingDirectory(to, stagingDirectory string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error
 
 	// CleanupStagingDirectory cleanups the staging directory.  It can be used to cleanup the staging directory on errors
+	// Deprecated: it will be removed soon.  Use CleanupStagedLayer instead.
 	CleanupStagingDirectory(stagingDirectory string) error
 
+	// ApplyStagedLayer combines the functions of CreateLayer and ApplyDiffFromStagingDirectory,
+	// marking the layer for automatic removal if applying the diff fails
+	// for any reason.
+	ApplyStagedLayer(args ApplyStagedLayerOptions) (*Layer, error)
+
+	// CleanupStagedLayer cleanups the staging directory.  It can be used to cleanup the staging directory on errors
+	CleanupStagedLayer(diffOutput *drivers.DriverWithDifferOutput) error
+
 	// DifferTarget gets the path to the differ target.
 	DifferTarget(id string) (string, error)
 
@@ -1421,8 +1444,7 @@ func (s *store) canUseShifting(uidmap, gidmap []idtools.IDMap) bool {
 	return true
 }
 
-func (s *store) PutLayer(id, parent string, names []string, mountLabel string, writeable bool, lOptions *LayerOptions, diff io.Reader) (*Layer, int64, error) {
-	var parentLayer *Layer
+func (s *store) putLayer(id, parent string, names []string, mountLabel string, writeable bool, lOptions *LayerOptions, diff io.Reader, slo *stagedLayerOptions) (*Layer, int64, error) {
 	rlstore, rlstores, err := s.bothLayerStoreKinds()
 	if err != nil {
 		return nil, -1, err
@@ -1435,6 +1457,8 @@ func (s *store) PutLayer(id, parent string, names []string, mountLabel string, w
 		return nil, -1, err
 	}
 	defer s.containerStore.stopWriting()
+
+	var parentLayer *Layer
 	var options LayerOptions
 	if lOptions != nil {
 		options = *lOptions
@@ -1508,7 +1532,11 @@ func (s *store) PutLayer(id, parent string, names []string, mountLabel string, w
 			GIDMap:         copyIDMap(gidMap),
 		}
 	}
-	return rlstore.create(id, parentLayer, names, mountLabel, nil, &layerOptions, writeable, diff)
+	return rlstore.create(id, parentLayer, names, mountLabel, nil, &layerOptions, writeable, diff, slo)
+}
+
+func (s *store) PutLayer(id, parent string, names []string, mountLabel string, writeable bool, lOptions *LayerOptions, diff io.Reader) (*Layer, int64, error) {
+	return s.putLayer(id, parent, names, mountLabel, writeable, lOptions, diff, nil)
 }
 
 func (s *store) CreateLayer(id, parent string, names []string, mountLabel string, writeable bool, options *LayerOptions) (*Layer, error) {
@@ -1718,7 +1746,7 @@ func (s *store) imageTopLayerForMapping(image *Image, ristore roImageStore, rlst
 		}
 	}
 	layerOptions.TemplateLayer = layer.ID
-	mappedLayer, _, err := rlstore.create("", parentLayer, nil, layer.MountLabel, nil, &layerOptions, false, nil)
+	mappedLayer, _, err := rlstore.create("", parentLayer, nil, layer.MountLabel, nil, &layerOptions, false, nil, nil)
 	if err != nil {
 		return nil, fmt.Errorf("creating an ID-mapped copy of layer %q: %w", layer.ID, err)
 	}
@@ -1889,7 +1917,7 @@ func (s *store) CreateContainer(id string, names []string, image, layer, metadat
 		options.Flags[mountLabelFlag] = mountLabel
 	}
 
-	clayer, _, err := rlstore.create(layer, imageTopLayer, nil, mlabel, options.StorageOpt, layerOptions, true, nil)
+	clayer, _, err := rlstore.create(layer, imageTopLayer, nil, mlabel, options.StorageOpt, layerOptions, true, nil, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -2954,22 +2982,42 @@ func (s *store) Diff(from, to string, options *DiffOptions) (io.ReadCloser, erro
 }
 
 func (s *store) ApplyDiffFromStagingDirectory(to, stagingDirectory string, diffOutput *drivers.DriverWithDifferOutput, options *drivers.ApplyDiffWithDifferOpts) error {
+	if stagingDirectory != diffOutput.Target {
+		return fmt.Errorf("invalid value for staging directory, it must be the same as the differ target directory")
+	}
 	_, err := writeToLayerStore(s, func(rlstore rwLayerStore) (struct{}, error) {
 		if !rlstore.Exists(to) {
 			return struct{}{}, ErrLayerUnknown
 		}
-		return struct{}{}, rlstore.ApplyDiffFromStagingDirectory(to, stagingDirectory, diffOutput, options)
+		return struct{}{}, rlstore.applyDiffFromStagingDirectory(to, diffOutput, options)
 	})
 	return err
 }
 
+func (s *store) ApplyStagedLayer(args ApplyStagedLayerOptions) (*Layer, error) {
+	slo := stagedLayerOptions{
+		DiffOutput:  args.DiffOutput,
+		DiffOptions: args.DiffOptions,
+	}
+
+	layer, _, err := s.putLayer(args.ID, args.ParentLayer, args.Names, args.MountLabel, args.Writeable, args.LayerOptions, nil, &slo)
+	return layer, err
+}
+
 func (s *store) CleanupStagingDirectory(stagingDirectory string) error {
 	_, err := writeToLayerStore(s, func(rlstore rwLayerStore) (struct{}, error) {
 		return struct{}{}, rlstore.CleanupStagingDirectory(stagingDirectory)
 	})
 	return err
 }
 
+func (s *store) CleanupStagedLayer(diffOutput *drivers.DriverWithDifferOutput) error {
+	_, err := writeToLayerStore(s, func(rlstore rwLayerStore) (struct{}, error) {
+		return struct{}{}, rlstore.CleanupStagingDirectory(diffOutput.Target)
+	})
+	return err
+}
+
 func (s *store) ApplyDiffWithDiffer(to string, options *drivers.ApplyDiffWithDifferOpts, differ drivers.Differ) (*drivers.DriverWithDifferOutput, error) {
 	return writeToLayerStore(s, func(rlstore rwLayerStore) (*drivers.DriverWithDifferOutput, error) {
 		if to != "" && !rlstore.Exists(to) {

userns.go

@@ -175,7 +175,7 @@ outer:
 
 	// We need to create a temporary layer so we can mount it and lookup the
 	// maximum IDs used.
-	clayer, _, err := rlstore.create("", topLayer, nil, "", nil, layerOptions, false, nil)
+	clayer, _, err := rlstore.create("", topLayer, nil, "", nil, layerOptions, false, nil, nil)
 	if err != nil {
 		return 0, err
 	}