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moby--moby/tags.go

186 lines
4.2 KiB
Go

package docker
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"sort"
"strings"
)
const DEFAULT_TAG = "latest"
type TagStore struct {
path string
graph *Graph
Repositories map[string]Repository
}
type Repository map[string]string
func NewTagStore(path string, graph *Graph) (*TagStore, error) {
abspath, err := filepath.Abs(path)
if err != nil {
return nil, err
}
store := &TagStore{
path: abspath,
graph: graph,
Repositories: make(map[string]Repository),
}
// 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
}
func (store *TagStore) Save() error {
// Store the json ball
jsonData, err := json.Marshal(store)
if err != nil {
return err
}
if err := ioutil.WriteFile(store.path, jsonData, 0600); err != nil {
return err
}
return nil
}
func (store *TagStore) Reload() error {
jsonData, err := ioutil.ReadFile(store.path)
if err != nil {
return err
}
if err := json.Unmarshal(jsonData, store); err != nil {
return err
}
return nil
}
func (store *TagStore) LookupImage(name string) (*Image, error) {
img, err := store.graph.Get(name)
if err != nil {
// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
// (so we can pass all errors here)
repoAndTag := strings.SplitN(name, ":", 2)
if len(repoAndTag) == 1 {
repoAndTag = append(repoAndTag, DEFAULT_TAG)
}
if i, err := store.GetImage(repoAndTag[0], repoAndTag[1]); err != nil {
return nil, err
} else if i == nil {
return nil, fmt.Errorf("Image does not exist: %s", name)
} else {
img = i
}
}
return img, nil
}
// Return a reverse-lookup table of all the names which refer to each image
// Eg. {"43b5f19b10584": {"base:latest", "base:v1"}}
func (store *TagStore) ById() map[string][]string {
byId := make(map[string][]string)
for repoName, repository := range store.Repositories {
for tag, id := range repository {
name := repoName + ":" + tag
if _, exists := byId[id]; !exists {
byId[id] = []string{name}
} else {
byId[id] = append(byId[id], name)
sort.Strings(byId[id])
}
}
}
return byId
}
func (store *TagStore) ImageName(id string) string {
if names, exists := store.ById()[id]; exists && len(names) > 0 {
return names[0]
}
return id
}
func (store *TagStore) Set(repoName, tag, imageName string, force bool) error {
img, err := store.LookupImage(imageName)
if err != nil {
return err
}
if tag == "" {
tag = DEFAULT_TAG
}
if err := validateRepoName(repoName); err != nil {
return err
}
if err := validateTagName(tag); err != nil {
return err
}
if err := store.Reload(); err != nil {
return err
}
var repo Repository
if r, exists := store.Repositories[repoName]; exists {
repo = r
} else {
repo = make(map[string]string)
if old, exists := store.Repositories[repoName]; exists && !force {
return fmt.Errorf("Tag %s:%s is already set to %s", repoName, tag, old)
}
store.Repositories[repoName] = repo
}
repo[tag] = img.Id
return store.Save()
}
func (store *TagStore) Get(repoName string) (Repository, error) {
if err := store.Reload(); err != nil {
return nil, err
}
if r, exists := store.Repositories[repoName]; exists {
return r, nil
}
return nil, nil
}
func (store *TagStore) GetImage(repoName, tag string) (*Image, error) {
repo, err := store.Get(repoName)
if err != nil {
return nil, err
} else if repo == nil {
return nil, nil
}
if revision, exists := repo[tag]; exists {
return store.graph.Get(revision)
}
return nil, nil
}
// Validate the name of a repository
func validateRepoName(name string) error {
if name == "" {
return fmt.Errorf("Repository name can't be empty")
}
if strings.Contains(name, ":") {
return fmt.Errorf("Illegal repository name: %s", name)
}
return nil
}
// Validate the name of a tag
func validateTagName(name string) error {
if name == "" {
return fmt.Errorf("Tag name can't be empty")
}
if strings.Contains(name, "/") || strings.Contains(name, ":") {
return fmt.Errorf("Illegal tag name: %s", name)
}
return nil
}