123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287 |
- package reference
- import (
- "encoding/json"
- "errors"
- "fmt"
- "os"
- "path/filepath"
- "sort"
- "sync"
- "github.com/docker/distribution/digest"
- "github.com/docker/docker/image"
- "github.com/docker/docker/pkg/ioutils"
- )
- var (
- // ErrDoesNotExist is returned if a reference is not found in the
- // store.
- ErrDoesNotExist = errors.New("reference does not exist")
- )
- // An Association is a tuple associating a reference with an image ID.
- type Association struct {
- Ref Named
- ImageID image.ID
- }
- // Store provides the set of methods which can operate on a tag store.
- type Store interface {
- References(id image.ID) []Named
- ReferencesByName(ref Named) []Association
- AddTag(ref Named, id image.ID, force bool) error
- AddDigest(ref Canonical, id image.ID, force bool) error
- Delete(ref Named) (bool, error)
- Get(ref Named) (image.ID, error)
- }
- type store struct {
- mu sync.RWMutex
- // jsonPath is the path to the file where the serialized tag data is
- // stored.
- jsonPath string
- // Repositories is a map of repositories, indexed by name.
- Repositories map[string]repository
- // referencesByIDCache is a cache of references indexed by ID, to speed
- // up References.
- referencesByIDCache map[image.ID]map[string]Named
- }
- // Repository maps tags to image IDs. The key is a stringified Reference,
- // including the repository name.
- type repository map[string]image.ID
- type lexicalRefs []Named
- func (a lexicalRefs) Len() int { return len(a) }
- func (a lexicalRefs) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
- func (a lexicalRefs) Less(i, j int) bool { return a[i].String() < a[j].String() }
- type lexicalAssociations []Association
- func (a lexicalAssociations) Len() int { return len(a) }
- func (a lexicalAssociations) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
- func (a lexicalAssociations) Less(i, j int) bool { return a[i].Ref.String() < a[j].Ref.String() }
- // NewReferenceStore creates a new reference store, tied to a file path where
- // the set of references are serialized in JSON format.
- func NewReferenceStore(jsonPath string) (Store, error) {
- abspath, err := filepath.Abs(jsonPath)
- if err != nil {
- return nil, err
- }
- store := &store{
- jsonPath: abspath,
- Repositories: make(map[string]repository),
- referencesByIDCache: make(map[image.ID]map[string]Named),
- }
- // Load the json file if it exists, otherwise create it.
- if err := store.reload(); os.IsNotExist(err) {
- if err := store.save(); err != nil {
- return nil, err
- }
- } else if err != nil {
- return nil, err
- }
- return store, nil
- }
- // AddTag adds a tag reference to the store. If force is set to true, existing
- // references can be overwritten. This only works for tags, not digests.
- func (store *store) AddTag(ref Named, id image.ID, force bool) error {
- if _, isCanonical := ref.(Canonical); isCanonical {
- return errors.New("refusing to create a tag with a digest reference")
- }
- return store.addReference(WithDefaultTag(ref), id, force)
- }
- // AddDigest adds a digest reference to the store.
- func (store *store) AddDigest(ref Canonical, id image.ID, force bool) error {
- return store.addReference(ref, id, force)
- }
- func (store *store) addReference(ref Named, id image.ID, force bool) error {
- if ref.Name() == string(digest.Canonical) {
- return errors.New("refusing to create an ambiguous tag using digest algorithm as name")
- }
- store.mu.Lock()
- defer store.mu.Unlock()
- repository, exists := store.Repositories[ref.Name()]
- if !exists || repository == nil {
- repository = make(map[string]image.ID)
- store.Repositories[ref.Name()] = repository
- }
- refStr := ref.String()
- oldID, exists := repository[refStr]
- if exists {
- // force only works for tags
- if digested, isDigest := ref.(Canonical); isDigest {
- return fmt.Errorf("Cannot overwrite digest %s", digested.Digest().String())
- }
- if !force {
- return fmt.Errorf("Conflict: Tag %s is already set to image %s, if you want to replace it, please use -f option", ref.String(), oldID.String())
- }
- if store.referencesByIDCache[oldID] != nil {
- delete(store.referencesByIDCache[oldID], refStr)
- if len(store.referencesByIDCache[oldID]) == 0 {
- delete(store.referencesByIDCache, oldID)
- }
- }
- }
- repository[refStr] = id
- if store.referencesByIDCache[id] == nil {
- store.referencesByIDCache[id] = make(map[string]Named)
- }
- store.referencesByIDCache[id][refStr] = ref
- return store.save()
- }
- // Delete deletes a reference from the store. It returns true if a deletion
- // happened, or false otherwise.
- func (store *store) Delete(ref Named) (bool, error) {
- ref = WithDefaultTag(ref)
- store.mu.Lock()
- defer store.mu.Unlock()
- repoName := ref.Name()
- repository, exists := store.Repositories[repoName]
- if !exists {
- return false, ErrDoesNotExist
- }
- refStr := ref.String()
- if id, exists := repository[refStr]; exists {
- delete(repository, refStr)
- if len(repository) == 0 {
- delete(store.Repositories, repoName)
- }
- if store.referencesByIDCache[id] != nil {
- delete(store.referencesByIDCache[id], refStr)
- if len(store.referencesByIDCache[id]) == 0 {
- delete(store.referencesByIDCache, id)
- }
- }
- return true, store.save()
- }
- return false, ErrDoesNotExist
- }
- // Get retrieves an item from the store by
- func (store *store) Get(ref Named) (image.ID, error) {
- ref = WithDefaultTag(ref)
- store.mu.RLock()
- defer store.mu.RUnlock()
- repository, exists := store.Repositories[ref.Name()]
- if !exists || repository == nil {
- return "", ErrDoesNotExist
- }
- id, exists := repository[ref.String()]
- if !exists {
- return "", ErrDoesNotExist
- }
- return id, nil
- }
- // References returns a slice of references to the given image ID. The slice
- // will be nil if there are no references to this image ID.
- func (store *store) References(id image.ID) []Named {
- store.mu.RLock()
- defer store.mu.RUnlock()
- // Convert the internal map to an array for two reasons:
- // 1) We must not return a mutable
- // 2) It would be ugly to expose the extraneous map keys to callers.
- var references []Named
- for _, ref := range store.referencesByIDCache[id] {
- references = append(references, ref)
- }
- sort.Sort(lexicalRefs(references))
- return references
- }
- // ReferencesByName returns the references for a given repository name.
- // If there are no references known for this repository name,
- // ReferencesByName returns nil.
- func (store *store) ReferencesByName(ref Named) []Association {
- store.mu.RLock()
- defer store.mu.RUnlock()
- repository, exists := store.Repositories[ref.Name()]
- if !exists {
- return nil
- }
- var associations []Association
- for refStr, refID := range repository {
- ref, err := ParseNamed(refStr)
- if err != nil {
- // Should never happen
- return nil
- }
- associations = append(associations,
- Association{
- Ref: ref,
- ImageID: refID,
- })
- }
- sort.Sort(lexicalAssociations(associations))
- return associations
- }
- func (store *store) save() error {
- // Store the json
- jsonData, err := json.Marshal(store)
- if err != nil {
- return err
- }
- return ioutils.AtomicWriteFile(store.jsonPath, jsonData, 0600)
- }
- func (store *store) reload() error {
- f, err := os.Open(store.jsonPath)
- if err != nil {
- return err
- }
- defer f.Close()
- if err := json.NewDecoder(f).Decode(&store); err != nil {
- return err
- }
- for _, repository := range store.Repositories {
- for refStr, refID := range repository {
- ref, err := ParseNamed(refStr)
- if err != nil {
- // Should never happen
- continue
- }
- if store.referencesByIDCache[refID] == nil {
- store.referencesByIDCache[refID] = make(map[string]Named)
- }
- store.referencesByIDCache[refID][refStr] = ref
- }
- }
- return nil
- }
|