func generateSnapshot(gun string, repo *tuf.Repo, store storage.MetaStore) (*storage.MetaUpdate, error) {
role, err := repo.GetBaseRole(data.CanonicalSnapshotRole)
if err != nil {
return nil, validation.ErrBadRoot{Msg: "root did not include snapshot role"}
}
algo, keyBytes, err := store.GetKey(gun, data.CanonicalSnapshotRole)
if err != nil {
return nil, validation.ErrBadHierarchy{Msg: "could not retrieve snapshot key. client must provide snapshot"}
}
foundK := data.NewPublicKey(algo, keyBytes)
validKey := false
for _, id := range role.ListKeyIDs() {
if id == foundK.ID() {
validKey = true
break
}
}
if !validKey {
return nil, validation.ErrBadHierarchy{
Missing: data.CanonicalSnapshotRole,
Msg: "no snapshot was included in update and server does not hold current snapshot key for repository"}
}
currentJSON, err := store.GetCurrent(gun, data.CanonicalSnapshotRole)
if err != nil {
if _, ok := err.(storage.ErrNotFound); !ok {
return nil, validation.ErrValidation{Msg: err.Error()}
}
}
var sn *data.SignedSnapshot
if currentJSON != nil {
sn = new(data.SignedSnapshot)
err := json.Unmarshal(currentJSON, sn)
if err != nil {
return nil, validation.ErrValidation{Msg: err.Error()}
}
err = repo.SetSnapshot(sn)
if err != nil {
return nil, validation.ErrValidation{Msg: err.Error()}
}
} else {
// this will only occurr if no snapshot has ever been created for the repository
err := repo.InitSnapshot()
if err != nil {
return nil, validation.ErrBadSnapshot{Msg: err.Error()}
}
}
sgnd, err := repo.SignSnapshot(data.DefaultExpires(data.CanonicalSnapshotRole))
if err != nil {
return nil, validation.ErrBadSnapshot{Msg: err.Error()}
}
sgndJSON, err := json.Marshal(sgnd)
if err != nil {
return nil, validation.ErrBadSnapshot{Msg: err.Error()}
}
return &storage.MetaUpdate{
Role: data.CanonicalSnapshotRole,
Version: repo.Snapshot.Signed.Version,
Data: sgndJSON,
}, nil
}
