// GetOrCreateTimestamp returns the current timestamp for the gun. This may mean
// a new timestamp is generated either because none exists, or because the current
// one has expired. Once generated, the timestamp is saved in the store.
// Additionally, if we had to generate a new snapshot for this timestamp,
// it is also saved in the store
func GetOrCreateTimestamp(gun string, store storage.MetaStore, cryptoService signed.CryptoService) (
*time.Time, []byte, error) {
updates := []storage.MetaUpdate{}
lastModified, timestampJSON, err := store.GetCurrent(gun, data.CanonicalTimestampRole)
if err != nil {
logrus.Debug("error retrieving timestamp: ", err.Error())
return nil, nil, err
}
prev := &data.SignedTimestamp{}
if err := json.Unmarshal(timestampJSON, prev); err != nil {
logrus.Error("Failed to unmarshal existing timestamp")
return nil, nil, err
}
snapChecksums, err := prev.GetSnapshot()
if err != nil || snapChecksums == nil {
return nil, nil, err
}
snapshotSha256Bytes, ok := snapChecksums.Hashes[notary.SHA256]
if !ok {
return nil, nil, data.ErrMissingMeta{Role: data.CanonicalSnapshotRole}
}
snapshotSha256Hex := hex.EncodeToString(snapshotSha256Bytes[:])
snapshotTime, snapshot, err := snapshot.GetOrCreateSnapshot(gun, snapshotSha256Hex, store, cryptoService)
if err != nil {
logrus.Debug("Previous timestamp, but no valid snapshot for GUN ", gun)
return nil, nil, err
}
snapshotRole := &data.SignedSnapshot{}
if err := json.Unmarshal(snapshot, snapshotRole); err != nil {
logrus.Error("Failed to unmarshal retrieved snapshot")
return nil, nil, err
}
// If the snapshot was generated, we should write it with the timestamp
if snapshotTime == nil {
updates = append(updates, storage.MetaUpdate{Role: data.CanonicalSnapshotRole, Version: snapshotRole.Signed.Version, Data: snapshot})
}
if !timestampExpired(prev) && !snapshotExpired(prev, snapshot) {
return lastModified, timestampJSON, nil
}
tsUpdate, err := createTimestamp(gun, prev, snapshot, store, cryptoService)
if err != nil {
logrus.Error("Failed to create a new timestamp")
return nil, nil, err
}
updates = append(updates, *tsUpdate)
c := time.Now()
// Write the timestamp, and potentially snapshot
if err = store.UpdateMany(gun, updates); err != nil {
return nil, nil, err
}
return &c, tsUpdate.Data, nil
}