Documentation improvements and code cleanups for graph package

Expand the godoc documentation for the graph package.

Centralize DefaultTag in the graphs/tag package instead of defining it
twice.

Remove some unnecessary "config" structs that are only used to pass
a few parameters to a function.

Simplify the GetParentsSize function - there's no reason for it to take
an accumulator argument.

Unexport some functions that aren't needed outside the package.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

api/client/build.go

@@ -526,7 +526,7 @@ func rewriteDockerfileFrom(dockerfileName string, translator func(string, regist
 			// Replace the line with a resolved "FROM repo@digest"
 			repo, tag := parsers.ParseRepositoryTag(matches[1])
 			if tag == "" {
-				tag = tags.DEFAULTTAG
+				tag = tags.DefaultTag
 			}
 			ref := registry.ParseReference(tag)
 

api/client/create.go

@@ -26,7 +26,7 @@ func (cli *DockerCli) pullImageCustomOut(image string, out io.Writer) error {
 	repos, tag := parsers.ParseRepositoryTag(image)
 	// pull only the image tagged 'latest' if no tag was specified
 	if tag == "" {
-		tag = tags.DEFAULTTAG
+		tag = tags.DefaultTag
 	}
 	v.Set("fromImage", repos)
 	v.Set("tag", tag)
@@ -96,7 +96,7 @@ func (cli *DockerCli) createContainer(config *runconfig.Config, hostConfig *runc
 
 	repo, tag := parsers.ParseRepositoryTag(config.Image)
 	if tag == "" {
-		tag = tags.DEFAULTTAG
+		tag = tags.DefaultTag
 	}
 
 	ref := registry.ParseReference(tag)

api/client/pull.go

@@ -25,7 +25,7 @@ func (cli *DockerCli) CmdPull(args ...string) error {
 
 	taglessRemote, tag := parsers.ParseRepositoryTag(remote)
 	if tag == "" && !*allTags {
-		tag = tags.DEFAULTTAG
+		tag = tags.DefaultTag
 		fmt.Fprintf(cli.out, "Using default tag: %s\n", tag)
 	} else if tag != "" && *allTags {
 		return fmt.Errorf("tag can't be used with --all-tags/-a")

api/server/server.go

@@ -364,14 +364,8 @@ func (s *Server) getImagesJSON(version version.Version, w http.ResponseWriter, r
 		return err
 	}
 
-	imagesConfig := graph.ImagesConfig{
-		Filters: r.Form.Get("filters"),
-		// FIXME this parameter could just be a match filter
-		Filter: r.Form.Get("filter"),
-		All:    boolValue(r, "all"),
-	}
-
-	images, err := s.daemon.Repositories().Images(&imagesConfig)
+	// FIXME: The filter parameter could just be a match filter
+	images, err := s.daemon.Repositories().Images(r.Form.Get("filters"), r.Form.Get("filter"), boolValue(r, "all"))
 	if err != nil {
 		return err
 	}
@@ -785,23 +779,17 @@ func (s *Server) postImagesCreate(version version.Version, w http.ResponseWriter
 		}
 
 		src := r.Form.Get("fromSrc")
-		imageImportConfig := &graph.ImageImportConfig{
-			Changes:   r.Form["changes"],
-			InConfig:  r.Body,
-			OutStream: output,
-		}
 
 		// 'err' MUST NOT be defined within this block, we need any error
 		// generated from the download to be available to the output
 		// stream processing below
 		var newConfig *runconfig.Config
-		newConfig, err = builder.BuildFromConfig(s.daemon, &runconfig.Config{}, imageImportConfig.Changes)
+		newConfig, err = builder.BuildFromConfig(s.daemon, &runconfig.Config{}, r.Form["changes"])
 		if err != nil {
 			return err
 		}
-		imageImportConfig.ContainerConfig = newConfig
 
-		err = s.daemon.Repositories().Import(src, repo, tag, imageImportConfig)
+		err = s.daemon.Repositories().Import(src, repo, tag, r.Body, output, newConfig)
 	}
 	if err != nil {
 		if !output.Flushed() {
@@ -909,14 +897,14 @@ func (s *Server) getImagesGet(version version.Version, w http.ResponseWriter, r
 	w.Header().Set("Content-Type", "application/x-tar")
 
 	output := ioutils.NewWriteFlusher(w)
-	imageExportConfig := &graph.ImageExportConfig{Outstream: output}
+	var names []string
 	if name, ok := vars["name"]; ok {
-		imageExportConfig.Names = []string{name}
+		names = []string{name}
 	} else {
-		imageExportConfig.Names = r.Form["names"]
+		names = r.Form["names"]
 	}
 
-	if err := s.daemon.Repositories().ImageExport(imageExportConfig); err != nil {
+	if err := s.daemon.Repositories().ImageExport(names, output); err != nil {
 		if !output.Flushed() {
 			return err
 		}

daemon/create.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/docker/docker/graph"
+	"github.com/docker/docker/graph/tags"
 	"github.com/docker/docker/image"
 	"github.com/docker/docker/pkg/parsers"
 	"github.com/docker/docker/runconfig"
@@ -27,7 +27,7 @@ func (daemon *Daemon) ContainerCreate(name string, config *runconfig.Config, hos
 		if daemon.Graph().IsNotExist(err, config.Image) {
 			_, tag := parsers.ParseRepositoryTag(config.Image)
 			if tag == "" {
-				tag = graph.DefaultTag
+				tag = tags.DefaultTag
 			}
 			return "", warnings, fmt.Errorf("No such image: %s (tag: %s)", config.Image, tag)
 		}

daemon/image_delete.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/api/types"
-	"github.com/docker/docker/graph"
+	"github.com/docker/docker/graph/tags"
 	"github.com/docker/docker/image"
 	"github.com/docker/docker/pkg/parsers"
 	"github.com/docker/docker/pkg/stringid"
@@ -27,16 +27,13 @@ func (daemon *Daemon) ImageDelete(name string, force, noprune bool) ([]types.Ima
 }
 
 func (daemon *Daemon) imgDeleteHelper(name string, list *[]types.ImageDelete, first, force, noprune bool) error {
-	var (
-		repoName, tag string
-		tags          = []string{}
-	)
+	var repoName, tag string
 	repoAndTags := make(map[string][]string)
 
 	// FIXME: please respect DRY and centralize repo+tag parsing in a single central place! -- shykes
 	repoName, tag = parsers.ParseRepositoryTag(name)
 	if tag == "" {
-		tag = graph.DefaultTag
+		tag = tags.DefaultTag
 	}
 
 	if name == "" {
@@ -111,7 +108,7 @@ func (daemon *Daemon) imgDeleteHelper(name string, list *[]types.ImageDelete, fi
 			}
 		}
 	}
-	tags = daemon.Repositories().ByID()[img.ID]
+	tags := daemon.Repositories().ByID()[img.ID]
 	if (len(tags) <= 1 && repoName == "") || len(tags) == 0 {
 		if len(byParents[img.ID]) == 0 {
 			if err := daemon.Repositories().DeleteAll(img.ID); err != nil {

graph/export.go

@@ -13,21 +13,12 @@ import (
 	"github.com/docker/docker/registry"
 )
 
-// ImageExportConfig holds list of names to be exported to a output stream.
-// All images with the given tag and all versions
-// containing the same tag are exported. The resulting output is an
-// uncompressed tar ball.
-type ImageExportConfig struct {
-	// Names is the set of tags to export.
-	Names []string
-	// OutStream is the writer where the images are written to.
-	Outstream io.Writer
-}
-
-// ImageExport exports list of images to a output stream specified in the config.
-// The exported images are archived into a tar when written to the output stream.
-func (s *TagStore) ImageExport(imageExportConfig *ImageExportConfig) error {
-
+// ImageExport exports list of images to a output stream specified in the
+// config. The exported images are archived into a tar when written to the
+// output stream. All images with the given tag and all versions containing the
+// same tag are exported. names is the set of tags to export, and outStream
+// is the writer which the images are written to.
+func (s *TagStore) ImageExport(names []string, outStream io.Writer) error {
 	// get image json
 	tempdir, err := ioutil.TempDir("", "docker-export-")
 	if err != nil {
@@ -44,7 +35,7 @@ func (s *TagStore) ImageExport(imageExportConfig *ImageExportConfig) error {
 			repo[tag] = id
 		}
 	}
-	for _, name := range imageExportConfig.Names {
+	for _, name := range names {
 		name = registry.NormalizeLocalName(name)
 		logrus.Debugf("Serializing %s", name)
 		rootRepo := s.Repositories[name]
@@ -107,7 +98,7 @@ func (s *TagStore) ImageExport(imageExportConfig *ImageExportConfig) error {
 	}
 	defer fs.Close()
 
-	if _, err := io.Copy(imageExportConfig.Outstream, fs); err != nil {
+	if _, err := io.Copy(outStream, fs); err != nil {
 		return err
 	}
 	logrus.Debugf("End export image")

graph/graph.go

@@ -152,10 +152,11 @@ func (graph *Graph) restore() error {
 	return nil
 }
 
-// IsNotExist detects whether an image exists by parsing the incoming error message.
-// FIXME: Implement error subclass instead of looking at the error text
-// Note: This is the way golang implements os.IsNotExists on Plan9
+// IsNotExist detects whether an image exists by parsing the incoming error
+// message.
 func (graph *Graph) IsNotExist(err error, id string) bool {
+	// FIXME: Implement error subclass instead of looking at the error text
+	// Note: This is the way golang implements os.IsNotExists on Plan9
 	return err != nil && (strings.Contains(strings.ToLower(err.Error()), "does not exist") || strings.Contains(strings.ToLower(err.Error()), "no such")) && strings.Contains(err.Error(), id)
 }
 
@@ -415,13 +416,13 @@ func (graph *Graph) ByParent() map[string][]*image.Image {
 	return byParent
 }
 
-// Retain keeps the images and layers that are in pulling chain so that they are not deleted.
-// If not, they may be deleted by rmi with dangling condition.
+// Retain keeps the images and layers that are in the pulling chain so that
+// they are not deleted. If not retained, they may be deleted by rmi.
 func (graph *Graph) Retain(sessionID string, layerIDs ...string) {
 	graph.retained.Add(sessionID, layerIDs)
 }
 
-// Release removes the referenced image id from the provided set of layers.
+// Release removes the referenced image ID from the provided set of layers.
 func (graph *Graph) Release(sessionID string, layerIDs ...string) {
 	graph.retained.Delete(sessionID, layerIDs)
 }

graph/history.go

@@ -67,7 +67,8 @@ func (graph *Graph) CheckDepth(img *image.Image) error {
 	return nil
 }
 
-// History returns a list of ImageHistory for the specified image name by walking the image lineage.
+// History returns a slice of ImageHistory structures for the specified image
+// name by walking the image lineage.
 func (s *TagStore) History(name string) ([]*types.ImageHistory, error) {
 	foundImage, err := s.LookupImage(name)
 	if err != nil {
@@ -102,7 +103,7 @@ func (s *TagStore) History(name string) ([]*types.ImageHistory, error) {
 	return history, err
 }
 
-// GetParent returns the parent image.
+// GetParent returns the parent image for the specified image.
 func (graph *Graph) GetParent(img *image.Image) (*image.Image, error) {
 	if img.Parent == "" {
 		return nil, nil
@@ -110,12 +111,12 @@ func (graph *Graph) GetParent(img *image.Image) (*image.Image, error) {
 	return graph.Get(img.Parent)
 }
 
-// GetParentsSize returns the size of the parent.
-func (graph *Graph) GetParentsSize(img *image.Image, size int64) int64 {
+// GetParentsSize returns the combined size of all parent images. If there is
+// no parent image or it's unavailable, it returns 0.
+func (graph *Graph) GetParentsSize(img *image.Image) int64 {
 	parentImage, err := graph.GetParent(img)
 	if err != nil || parentImage == nil {
-		return size
+		return 0
 	}
-	size += parentImage.Size
-	return graph.GetParentsSize(parentImage, size)
+	return parentImage.Size + graph.GetParentsSize(parentImage)
 }

graph/import.go

@@ -13,22 +13,11 @@ import (
 	"github.com/docker/docker/utils"
 )
 
-// ImageImportConfig holds configuration to import a image.
-type ImageImportConfig struct {
-	// Changes are the container changes written to top layer.
-	Changes []string
-	// InConfig is the input stream containers layered data.
-	InConfig io.ReadCloser
-	// OutStream is the output stream where the image is written.
-	OutStream io.Writer
-	// ContainerConfig is the configuration of commit container.
-	ContainerConfig *runconfig.Config
-}
-
-// Import allows to download image from  a archive.
-// If the src is a URL, the content is downloaded from the archive. If the source is '-' then the imageImportConfig.InConfig
-// reader will be used to load the image. Once all the layers required are loaded locally, image is then tagged using the tag specified.
-func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig *ImageImportConfig) error {
+// Import imports an image, getting the archived layer data either from
+// inConfig (if src is "-"), or from a URI specified in src. Progress output is
+// written to outStream. Repository and tag names can optionally be given in
+// the repo and tag arguments, respectively.
+func (s *TagStore) Import(src string, repo string, tag string, inConfig io.ReadCloser, outStream io.Writer, containerConfig *runconfig.Config) error {
 	var (
 		sf      = streamformatter.NewJSONStreamFormatter()
 		archive archive.ArchiveReader
@@ -36,7 +25,7 @@ func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig
 	)
 
 	if src == "-" {
-		archive = imageImportConfig.InConfig
+		archive = inConfig
 	} else {
 		u, err := url.Parse(src)
 		if err != nil {
@@ -47,14 +36,14 @@ func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig
 			u.Host = src
 			u.Path = ""
 		}
-		imageImportConfig.OutStream.Write(sf.FormatStatus("", "Downloading from %s", u))
+		outStream.Write(sf.FormatStatus("", "Downloading from %s", u))
 		resp, err = httputils.Download(u.String())
 		if err != nil {
 			return err
 		}
 		progressReader := progressreader.New(progressreader.Config{
 			In:        resp.Body,
-			Out:       imageImportConfig.OutStream,
+			Out:       outStream,
 			Formatter: sf,
 			Size:      int(resp.ContentLength),
 			NewLines:  true,
@@ -65,7 +54,7 @@ func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig
 		archive = progressReader
 	}
 
-	img, err := s.graph.Create(archive, "", "", "Imported from "+src, "", nil, imageImportConfig.ContainerConfig)
+	img, err := s.graph.Create(archive, "", "", "Imported from "+src, "", nil, containerConfig)
 	if err != nil {
 		return err
 	}
@@ -75,7 +64,7 @@ func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig
 			return err
 		}
 	}
-	imageImportConfig.OutStream.Write(sf.FormatStatus("", img.ID))
+	outStream.Write(sf.FormatStatus("", img.ID))
 	logID := img.ID
 	if tag != "" {
 		logID = utils.ImageReference(logID, tag)

graph/list.go

@@ -18,25 +18,20 @@ var acceptedImageFilterTags = map[string]struct{}{
 	"label":    {},
 }
 
-// ImagesConfig defines the criteria to obtain a list of images.
-type ImagesConfig struct {
-	// Filters is supported list of filters used to get list of images.
-	Filters string
-	// Filter the list of images by name.
-	Filter string
-	// All inditest that all the images will be returned in the list, if set to true.
-	All bool
-}
-
-// byCreated is a temporary type used to sort list of images on their field 'Created'.
+// byCreated is a temporary type used to sort a list of images by creation
+// time.
 type byCreated []*types.Image
 
 func (r byCreated) Len() int           { return len(r) }
 func (r byCreated) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
 func (r byCreated) Less(i, j int) bool { return r[i].Created < r[j].Created }
 
-// Images provide list of images based on selection criteria.
-func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
+// Images returns a filtered list of images. filterArgs is a JSON-encoded set
+// of filter arguments which will be interpreted by pkg/parsers/filters.
+// filter is a shell glob string applied to repository names. The argument
+// named all controls whether all images in the graph are filtered, or just
+// the heads.
+func (s *TagStore) Images(filterArgs, filter string, all bool) ([]*types.Image, error) {
 	var (
 		allImages  map[string]*image.Image
 		err        error
@@ -44,7 +39,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 		filtLabel  = false
 	)
 
-	imageFilters, err := filters.FromParam(config.Filters)
+	imageFilters, err := filters.FromParam(filterArgs)
 	if err != nil {
 		return nil, err
 	}
@@ -64,7 +59,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 
 	_, filtLabel = imageFilters["label"]
 
-	if config.All && filtTagged {
+	if all && filtTagged {
 		allImages = s.graph.Map()
 	} else {
 		allImages = s.graph.Heads()
@@ -73,8 +68,8 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 	lookup := make(map[string]*types.Image)
 	s.Lock()
 	for repoName, repository := range s.Repositories {
-		if config.Filter != "" {
-			if match, _ := path.Match(config.Filter, repoName); !match {
+		if filter != "" {
+			if match, _ := path.Match(filter, repoName); !match {
 				continue
 			}
 		}
@@ -106,7 +101,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 					newImage.ID = image.ID
 					newImage.Created = int(image.Created.Unix())
 					newImage.Size = int(image.Size)
-					newImage.VirtualSize = int(s.graph.GetParentsSize(image, 0) + image.Size)
+					newImage.VirtualSize = int(s.graph.GetParentsSize(image) + image.Size)
 					newImage.Labels = image.ContainerConfig.Labels
 
 					if utils.DigestReference(ref) {
@@ -131,7 +126,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 	}
 
 	// Display images which aren't part of a repository/tag
-	if config.Filter == "" || filtLabel {
+	if filter == "" || filtLabel {
 		for _, image := range allImages {
 			if !imageFilters.MatchKVList("label", image.ContainerConfig.Labels) {
 				continue
@@ -143,7 +138,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 			newImage.ID = image.ID
 			newImage.Created = int(image.Created.Unix())
 			newImage.Size = int(image.Size)
-			newImage.VirtualSize = int(s.graph.GetParentsSize(image, 0) + image.Size)
+			newImage.VirtualSize = int(s.graph.GetParentsSize(image) + image.Size)
 			newImage.Labels = image.ContainerConfig.Labels
 
 			images = append(images, newImage)

graph/load.go

@@ -71,7 +71,7 @@ func (s *TagStore) Load(inTar io.ReadCloser, outStream io.Writer) error {
 
 	for imageName, tagMap := range repositories {
 		for tag, address := range tagMap {
-			if err := s.SetLoad(imageName, tag, address, true, outStream); err != nil {
+			if err := s.setLoad(imageName, tag, address, true, outStream); err != nil {
 				return err
 			}
 		}

graph/pull.go

@@ -13,15 +13,18 @@ import (
 
 // ImagePullConfig stores pull configuration.
 type ImagePullConfig struct {
-	// MetaHeaders store meta data about the image (DockerHeaders with prefix X-Meta- in the request).
+	// MetaHeaders stores HTTP headers with metadata about the image
+	// (DockerHeaders with prefix X-Meta- in the request).
 	MetaHeaders map[string][]string
-	// AuthConfig holds authentication information for authorizing with the registry.
+	// AuthConfig holds authentication credentials for authenticating with
+	// the registry.
 	AuthConfig *cliconfig.AuthConfig
-	// OutStream is the output writer for showing the status of the pull operation.
+	// OutStream is the output writer for showing the status of the pull
+	// operation.
 	OutStream io.Writer
 }
 
-// Puller is an interface to define Pull behavior.
+// Puller is an interface that abstracts pulling for different API versions.
 type Puller interface {
 	// Pull tries to pull the image referenced by `tag`
 	// Pull returns an error if any, as well as a boolean that determines whether to retry Pull on the next configured endpoint.
@@ -30,7 +33,11 @@ type Puller interface {
 	Pull(tag string) (fallback bool, err error)
 }
 
-// NewPuller returns a new instance of an implementation conforming to Puller interface.
+// NewPuller returns a Puller interface that will pull from either a v1 or v2
+// registry. The endpoint argument contains a Version field that determines
+// whether a v1 or v2 puller will be created. The other parameters are passed
+// through to the underlying puller implementation for use during the actual
+// pull operation.
 func NewPuller(s *TagStore, endpoint registry.APIEndpoint, repoInfo *registry.RepositoryInfo, imagePullConfig *ImagePullConfig, sf *streamformatter.StreamFormatter) (Puller, error) {
 	switch endpoint.Version {
 	case registry.APIVersion2:
@@ -53,7 +60,8 @@ func NewPuller(s *TagStore, endpoint registry.APIEndpoint, repoInfo *registry.Re
 	return nil, fmt.Errorf("unknown version %d for registry %s", endpoint.Version, endpoint.URL)
 }
 
-// Pull downloads a image with specified name and tag from the repo.
+// Pull initiates a pull operation. image is the repository name to pull, and
+// tag may be either empty, or indicate a specific tag to pull.
 func (s *TagStore) Pull(image string, tag string, imagePullConfig *ImagePullConfig) error {
 	var sf = streamformatter.NewJSONStreamFormatter()
 
@@ -133,7 +141,10 @@ func (s *TagStore) Pull(image string, tag string, imagePullConfig *ImagePullConf
 	return lastErr
 }
 
-// writeStatus shows status of the pull command.
+// writeStatus writes a status message to out. If layersDownloaded is true, the
+// status message indicates that a newer image was downloaded. Otherwise, it
+// indicates that the image is up to date. requestedTag is the tag the message
+// will refer to.
 func writeStatus(requestedTag string, out io.Writer, sf *streamformatter.StreamFormatter, layersDownloaded bool) {
 	if layersDownloaded {
 		out.Write(sf.FormatStatus("", "Status: Downloaded newer image for %s", requestedTag))

graph/push.go

@@ -12,17 +12,21 @@ import (
 
 // ImagePushConfig stores push configuration.
 type ImagePushConfig struct {
-	// MetaHeaders store meta data about the image (DockerHeaders with prefix X-Meta- in the request).
+	// MetaHeaders store HTTP headers with metadata about the image
+	// (DockerHeaders with prefix X-Meta- in the request).
 	MetaHeaders map[string][]string
-	// AuthConfig holds authentication information for authorizing with the registry.
+	// AuthConfig holds authentication credentials for authenticating with
+	// the registry.
 	AuthConfig *cliconfig.AuthConfig
-	// Tag is the specific variant of the image to be pushed, this tag used when image is pushed. If no tag is provided, all tags will be pushed.
+	// Tag is the specific variant of the image to be pushed.
+	// If no tag is provided, all tags will be pushed.
 	Tag string
-	// OutStream is the output writer for showing the status of the push operation.
+	// OutStream is the output writer for showing the status of the push
+	// operation.
 	OutStream io.Writer
 }
 
-// Pusher is an interface to define Push behavior.
+// Pusher is an interface that abstracts pushing for different API versions.
 type Pusher interface {
 	// Push tries to push the image configured at the creation of Pusher.
 	// Push returns an error if any, as well as a boolean that determines whether to retry Push on the next configured endpoint.
@@ -31,7 +35,11 @@ type Pusher interface {
 	Push() (fallback bool, err error)
 }
 
-// NewPusher returns a new instance of an implementation conforming to Pusher interface.
+// NewPusher creates a new Pusher interface that will push to either a v1 or v2
+// registry. The endpoint argument contains a Version field that determines
+// whether a v1 or v2 pusher will be created. The other parameters are passed
+// through to the underlying pusher implementation for use during the actual
+// push operation.
 func (s *TagStore) NewPusher(endpoint registry.APIEndpoint, localRepo Repository, repoInfo *registry.RepositoryInfo, imagePushConfig *ImagePushConfig, sf *streamformatter.StreamFormatter) (Pusher, error) {
 	switch endpoint.Version {
 	case registry.APIVersion2:
@@ -57,10 +65,10 @@ func (s *TagStore) NewPusher(endpoint registry.APIEndpoint, localRepo Repository
 	return nil, fmt.Errorf("unknown version %d for registry %s", endpoint.Version, endpoint.URL)
 }
 
-// FIXME: Allow to interrupt current push when new push of same image is done.
-
-// Push a image to the repo.
+// Push initiates a push operation on the repository named localName.
 func (s *TagStore) Push(localName string, imagePushConfig *ImagePushConfig) error {
+	// FIXME: Allow to interrupt current push when new push of same image is done.
+
 	var sf = streamformatter.NewJSONStreamFormatter()
 
 	// Resolve the Repository name from fqn to RepositoryInfo

graph/registry.go

@@ -27,7 +27,9 @@ func (dcs dumbCredentialStore) Basic(*url.URL) (string, string) {
 	return dcs.auth.Username, dcs.auth.Password
 }
 
-// NewV2Repository creates a v2 only repository.
+// NewV2Repository returns a repository (v2 only). It creates a HTTP transport
+// providing timeout settings and authentication support, and also verifies the
+// remote API version.
 func NewV2Repository(repoInfo *registry.RepositoryInfo, endpoint registry.APIEndpoint, metaHeaders http.Header, authConfig *cliconfig.AuthConfig) (distribution.Repository, error) {
 	ctx := context.Background()
 

graph/service.go

@@ -10,6 +10,8 @@ import (
 	"github.com/docker/docker/api/types"
 )
 
+// lookupRaw looks up an image by name in a TagStore and returns the raw JSON
+// describing the image.
 func (s *TagStore) lookupRaw(name string) ([]byte, error) {
 	image, err := s.LookupImage(name)
 	if err != nil || image == nil {
@@ -24,7 +26,8 @@ func (s *TagStore) lookupRaw(name string) ([]byte, error) {
 	return imageInspectRaw, nil
 }
 
-// Lookup return an image encoded in JSON
+// Lookup looks up an image by name in a TagStore and returns it as an
+// ImageInspect structure.
 func (s *TagStore) Lookup(name string) (*types.ImageInspect, error) {
 	image, err := s.LookupImage(name)
 	if err != nil || image == nil {
@@ -44,7 +47,7 @@ func (s *TagStore) Lookup(name string) (*types.ImageInspect, error) {
 		Architecture:    image.Architecture,
 		Os:              image.OS,
 		Size:            image.Size,
-		VirtualSize:     s.graph.GetParentsSize(image, 0) + image.Size,
+		VirtualSize:     s.graph.GetParentsSize(image) + image.Size,
 	}
 
 	imageInspect.GraphDriver.Name = s.graph.driver.String()

graph/tags.go

@@ -24,13 +24,13 @@ import (
 	"github.com/docker/libtrust"
 )
 
-// DefaultTag defines the default tag used when performing images related actions and no tag string is specified
-const DefaultTag = "latest"
-
-// TagStore contains information to push and pull to the repo.
+// TagStore manages repositories. It encompasses the Graph used for versioned
+// storage, as well as various services involved in pushing and pulling
+// repositories.
 type TagStore struct {
-	path         string
-	graph        *Graph
+	path  string
+	graph *Graph
+	// Repositories is a map of repositories, indexed by name.
 	Repositories map[string]Repository
 	trustKey     libtrust.PrivateKey
 	sync.Mutex
@@ -43,7 +43,7 @@ type TagStore struct {
 	trustService    *trust.TrustStore
 }
 
-// Repository maps image id to image tag.
+// Repository maps tags to image IDs.
 type Repository map[string]string
 
 // Update updates repository mapping with content of repository 'u'.
@@ -53,7 +53,8 @@ func (r Repository) Update(u Repository) {
 	}
 }
 
-// Contains returns true if the contents of u Repository, are wholly contained in r Repository.
+// Contains returns true if the contents of Repository u are wholly contained
+// in Repository r.
 func (r Repository) Contains(u Repository) bool {
 	for k, v := range u {
 		// if u's key is not present in r OR u's key is present, but not the same value
@@ -64,16 +65,23 @@ func (r Repository) Contains(u Repository) bool {
 	return true
 }
 
-// TagStoreConfig holds tag store configuration.
+// TagStoreConfig provides parameters for a new TagStore.
 type TagStoreConfig struct {
-	Graph    *Graph
-	Key      libtrust.PrivateKey
+	// Graph is the versioned image store
+	Graph *Graph
+	// Key is the private key to use for signing manifests.
+	Key libtrust.PrivateKey
+	// Registry is the registry service to use for TLS configuration and
+	// endpoint lookup.
 	Registry *registry.Service
-	Events   *events.Events
-	Trust    *trust.TrustStore
+	// Events is the events service to use for logging.
+	Events *events.Events
+	// Trust is the trust service to use for push and pull operations.
+	Trust *trust.TrustStore
 }
 
-// NewTagStore creates a tag store to specified path.
+// NewTagStore creates a new TagStore at specified path, using the parameters
+// and services provided in cfg.
 func NewTagStore(path string, cfg *TagStoreConfig) (*TagStore, error) {
 	abspath, err := filepath.Abs(path)
 	if err != nil {
@@ -126,13 +134,15 @@ func (store *TagStore) reload() error {
 	return nil
 }
 
-// LookupImage returns the image from the store.
+// LookupImage returns pointer to an Image struct corresponding to the given
+// name. The name can include an optional tag; otherwise the default tag will
+// be used.
 func (store *TagStore) LookupImage(name string) (*image.Image, error) {
 	// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
 	// (so we can pass all errors here)
 	repoName, ref := parsers.ParseRepositoryTag(name)
 	if ref == "" {
-		ref = DefaultTag
+		ref = tags.DefaultTag
 	}
 	var (
 		err error
@@ -158,8 +168,8 @@ func (store *TagStore) LookupImage(name string) (*image.Image, error) {
 	return img, nil
 }
 
-// ByID returns a reverse-lookup table of all the names which refer to each image.
-// Eg. {"43b5f19b10584": {"base:latest", "base:v1"}}
+// ByID returns a reverse-lookup table of all the names which refer to each
+// image - e.g. {"43b5f19b10584": {"base:latest", "base:v1"}}
 func (store *TagStore) ByID() map[string][]string {
 	store.Lock()
 	defer store.Unlock()
@@ -178,7 +188,7 @@ func (store *TagStore) ByID() map[string][]string {
 	return byID
 }
 
-// ImageName returns name of the image.
+// ImageName returns name of an image, given the image's ID.
 func (store *TagStore) ImageName(id string) string {
 	if names, exists := store.ByID()[id]; exists && len(names) > 0 {
 		return names[0]
@@ -186,7 +196,7 @@ func (store *TagStore) ImageName(id string) string {
 	return stringid.TruncateID(id)
 }
 
-// DeleteAll removes images identified by a specific id from the store.
+// DeleteAll removes images identified by a specific ID from the store.
 func (store *TagStore) DeleteAll(id string) error {
 	names, exists := store.ByID()[id]
 	if !exists || len(names) == 0 {
@@ -207,7 +217,9 @@ func (store *TagStore) DeleteAll(id string) error {
 	return nil
 }
 
-// Delete removes a repo identified by a given name from the store
+// Delete deletes a repository or a specific tag. If ref is empty, the entire
+// repository named repoName will be deleted; otherwise only the tag named by
+// ref will be deleted.
 func (store *TagStore) Delete(repoName, ref string) (bool, error) {
 	store.Lock()
 	defer store.Unlock()
@@ -240,14 +252,16 @@ func (store *TagStore) Delete(repoName, ref string) (bool, error) {
 	return deleted, store.save()
 }
 
-// Tag adds a new tag to an existing image.
+// Tag creates a tag in the repository reponame, pointing to the image named
+// imageName. If force is true, an existing tag with the same name may be
+// overwritten.
 func (store *TagStore) Tag(repoName, tag, imageName string, force bool) error {
-	return store.SetLoad(repoName, tag, imageName, force, nil)
+	return store.setLoad(repoName, tag, imageName, force, nil)
 }
 
-// SetLoad stores the image to the store.
+// setLoad stores the image to the store.
 // If the imageName is already in the repo then a '-f' flag should be used to replace existing image.
-func (store *TagStore) SetLoad(repoName, tag, imageName string, force bool, out io.Writer) error {
+func (store *TagStore) setLoad(repoName, tag, imageName string, force bool, out io.Writer) error {
 	img, err := store.LookupImage(imageName)
 	store.Lock()
 	defer store.Unlock()
@@ -255,7 +269,7 @@ func (store *TagStore) SetLoad(repoName, tag, imageName string, force bool, out
 		return err
 	}
 	if tag == "" {
-		tag = tags.DEFAULTTAG
+		tag = tags.DefaultTag
 	}
 	if err := validateRepoName(repoName); err != nil {
 		return err
@@ -331,7 +345,7 @@ func (store *TagStore) SetDigest(repoName, digest, imageName string) error {
 	return store.save()
 }
 
-// Get returns a repo from the store.
+// Get returns the Repository tag/image map for a given repository.
 func (store *TagStore) Get(repoName string) (Repository, error) {
 	store.Lock()
 	defer store.Unlock()
@@ -345,7 +359,8 @@ func (store *TagStore) Get(repoName string) (Repository, error) {
 	return nil, nil
 }
 
-// GetImage returns an image from a given repo from the store.
+// GetImage returns a pointer to an Image structure describing the image
+// referred to by refOrID inside repository repoName.
 func (store *TagStore) GetImage(repoName, refOrID string) (*image.Image, error) {
 	repo, err := store.Get(repoName)
 
@@ -375,7 +390,8 @@ func (store *TagStore) GetImage(repoName, refOrID string) (*image.Image, error)
 	return nil, nil
 }
 
-// GetRepoRefs returns list of repos.
+// GetRepoRefs returns a map with image IDs as keys, and slices listing
+// repo/tag references as the values. It covers all repositories.
 func (store *TagStore) GetRepoRefs() map[string][]string {
 	store.Lock()
 	reporefs := make(map[string][]string)

graph/tags/tags.go

@@ -6,8 +6,12 @@ import (
 	"github.com/docker/distribution/registry/api/v2"
 )
 
-const DEFAULTTAG = "latest"
+// DefaultTag is the default tag for the case where no explicit tag is
+// specified.
+const DefaultTag = "latest"
 
+// ErrTagInvalidFormat is an error type used when the tag name has invalid
+// characters or is longer than allowed.
 type ErrTagInvalidFormat struct {
 	name string
 }

graph/tags_unit_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/docker/docker/daemon/events"
 	"github.com/docker/docker/daemon/graphdriver"
 	_ "github.com/docker/docker/daemon/graphdriver/vfs" // import the vfs driver so it is used in the tests
+	"github.com/docker/docker/graph/tags"
 	"github.com/docker/docker/image"
 	"github.com/docker/docker/trust"
 	"github.com/docker/docker/utils"
@@ -119,17 +120,17 @@ func TestLookupImage(t *testing.T) {
 		testOfficialImageName + ":" + testOfficialImageID,
 		testOfficialImageName + ":" + testOfficialImageIDShort,
 		testOfficialImageName,
-		testOfficialImageName + ":" + DefaultTag,
+		testOfficialImageName + ":" + tags.DefaultTag,
 		"docker.io/" + testOfficialImageName,
-		"docker.io/" + testOfficialImageName + ":" + DefaultTag,
+		"docker.io/" + testOfficialImageName + ":" + tags.DefaultTag,
 		"index.docker.io/" + testOfficialImageName,
-		"index.docker.io/" + testOfficialImageName + ":" + DefaultTag,
+		"index.docker.io/" + testOfficialImageName + ":" + tags.DefaultTag,
 		"library/" + testOfficialImageName,
-		"library/" + testOfficialImageName + ":" + DefaultTag,
+		"library/" + testOfficialImageName + ":" + tags.DefaultTag,
 		"docker.io/library/" + testOfficialImageName,
-		"docker.io/library/" + testOfficialImageName + ":" + DefaultTag,
+		"docker.io/library/" + testOfficialImageName + ":" + tags.DefaultTag,
 		"index.docker.io/library/" + testOfficialImageName,
-		"index.docker.io/library/" + testOfficialImageName + ":" + DefaultTag,
+		"index.docker.io/library/" + testOfficialImageName + ":" + tags.DefaultTag,
 	}
 
 	privateLookups := []string{
@@ -138,7 +139,7 @@ func TestLookupImage(t *testing.T) {
 		testPrivateImageName + ":" + testPrivateImageID,
 		testPrivateImageName + ":" + testPrivateImageIDShort,
 		testPrivateImageName,
-		testPrivateImageName + ":" + DefaultTag,
+		testPrivateImageName + ":" + tags.DefaultTag,
 	}
 
 	invalidLookups := []string{