Method latestDataKey

key_registry.go:315–379

latestDataKey will give you the latest generated datakey based on the rotation period. If the last generated datakey lifetime exceeds the rotation period. It'll create new datakey.

()

// period. If the last generated datakey lifetime exceeds the rotation period.
// It'll create new datakey.
func (kr *KeyRegistry) latestDataKey() (*pb.DataKey, error) {
	if len(kr.opt.EncryptionKey) == 0 {
		// nil is for no encryption.
		return nil, nil
	}
	// validKey return datakey if the last generated key duration less than
	// rotation duration.
	validKey := func() (*pb.DataKey, bool) {
		// Time diffrence from the last generated time.
		diff := time.Since(time.Unix(kr.lastCreated, 0))
		if diff < kr.opt.EncryptionKeyRotationDuration {
			return kr.dataKeys[kr.nextKeyID], true
		}
		return nil, false
	}
	kr.RLock()
	key, valid := validKey()
	kr.RUnlock()
	if valid {
		// If less than EncryptionKeyRotationDuration, returns the last generated key.
		return key, nil
	}
	kr.Lock()
	defer kr.Unlock()
	// Key might have generated by another go routine. So,
	// checking once again.
	key, valid = validKey()
	if valid {
		return key, nil
	}
	k := make([]byte, len(kr.opt.EncryptionKey))
	iv, err := y.GenerateIV()
	if err != nil {
		return nil, err
	}
	_, err = rand.Read(k)
	if err != nil {
		return nil, err
	}
	// Otherwise Increment the KeyID and generate new datakey.
	kr.nextKeyID++
	dk := &pb.DataKey{
		KeyId:     kr.nextKeyID,
		Data:      k,
		CreatedAt: time.Now().Unix(),
		Iv:        iv,
	}
	// Don't store the datakey on file if badger is running in InMemory mode.
	if !kr.opt.InMemory {
		// Store the datekey.
		buf := &bytes.Buffer{}
		if err = storeDataKey(buf, kr.opt.EncryptionKey, dk); err != nil {
			return nil, err
		}
		// Persist the datakey to the disk
		if _, err = kr.fp.Write(buf.Bytes()); err != nil {
			return nil, err
		}