Esempio n. 1
0
// Implements storage.Interface.
func (h *etcdHelper) GuaranteedUpdate(ctx context.Context, key string, ptrToType runtime.Object, ignoreNotFound bool, tryUpdate storage.UpdateFunc) error {
	if ctx == nil {
		glog.Errorf("Context is nil")
	}
	v, err := conversion.EnforcePtr(ptrToType)
	if err != nil {
		// Panic is appropriate, because this is a programming error.
		panic("need ptr to type")
	}
	key = h.prefixEtcdKey(key)
	for {
		obj := reflect.New(v.Type()).Interface().(runtime.Object)
		origBody, node, res, err := h.bodyAndExtractObj(ctx, key, obj, ignoreNotFound)
		if err != nil {
			return err
		}
		meta := storage.ResponseMeta{}
		if node != nil {
			meta.TTL = node.TTL
			if node.Expiration != nil {
				meta.Expiration = node.Expiration
			}
			meta.ResourceVersion = node.ModifiedIndex
		}
		// Get the object to be written by calling tryUpdate.
		ret, newTTL, err := tryUpdate(obj, meta)
		if err != nil {
			return err
		}

		index := uint64(0)
		ttl := uint64(0)
		if node != nil {
			index = node.ModifiedIndex
			if node.TTL != 0 {
				ttl = uint64(node.TTL)
			}
			if node.Expiration != nil && ttl == 0 {
				ttl = 1
			}
		} else if res != nil {
			index = res.Index
		}

		if newTTL != nil {
			if ttl != 0 && *newTTL == 0 {
				// TODO: remove this after we have verified this is no longer an issue
				glog.V(4).Infof("GuaranteedUpdate is clearing TTL for %q, may not be intentional", key)
			}
			ttl = *newTTL
		}

		// Since update object may have a resourceVersion set, we need to clear it here.
		if err := h.versioner.UpdateObject(ret, meta.Expiration, 0); err != nil {
			return errors.New("resourceVersion cannot be set on objects store in etcd")
		}

		data, err := runtime.Encode(h.codec, ret)
		if err != nil {
			return err
		}

		// First time this key has been used, try creating new value.
		if index == 0 {
			startTime := time.Now()
			opts := etcd.SetOptions{
				TTL:       time.Duration(ttl) * time.Second,
				PrevExist: etcd.PrevNoExist,
			}
			response, err := h.etcdKeysAPI.Set(ctx, key, string(data), &opts)
			metrics.RecordEtcdRequestLatency("create", getTypeName(ptrToType), startTime)
			if etcdutil.IsEtcdNodeExist(err) {
				continue
			}
			_, _, err = h.extractObj(response, err, ptrToType, false, false)
			return err
		}

		if string(data) == origBody {
			// If we don't send an update, we simply return the currently existing
			// version of the object.
			_, _, err := h.extractObj(res, nil, ptrToType, ignoreNotFound, false)
			return err
		}

		startTime := time.Now()
		// Swap origBody with data, if origBody is the latest etcd data.
		opts := etcd.SetOptions{
			PrevValue: origBody,
			PrevIndex: index,
			TTL:       time.Duration(ttl) * time.Second,
		}
		response, err := h.etcdKeysAPI.Set(ctx, key, string(data), &opts)
		metrics.RecordEtcdRequestLatency("compareAndSwap", getTypeName(ptrToType), startTime)
		if etcdutil.IsEtcdTestFailed(err) {
			// Try again.
			continue
		}
		_, _, err = h.extractObj(response, err, ptrToType, false, false)
		return err
	}
}
// Implements storage.Interface.
func (h *etcdHelper) GuaranteedUpdate(ctx context.Context, key string, ptrToType runtime.Object, ignoreNotFound bool, tryUpdate storage.UpdateFunc) error {
	if ctx == nil {
		glog.Errorf("Context is nil")
	}
	v, err := conversion.EnforcePtr(ptrToType)
	if err != nil {
		// Panic is appropriate, because this is a programming error.
		panic("need ptr to type")
	}
	key = h.prefixEtcdKey(key)
	for {
		obj := reflect.New(v.Type()).Interface().(runtime.Object)
		origBody, node, res, err := h.bodyAndExtractObj(ctx, key, obj, ignoreNotFound)
		if err != nil {
			return err
		}
		meta := storage.ResponseMeta{}
		if node != nil {
			meta.TTL = node.TTL
			if node.Expiration != nil {
				meta.Expiration = node.Expiration
			}
			meta.ResourceVersion = node.ModifiedIndex
		}
		// Get the object to be written by calling tryUpdate.
		ret, newTTL, err := tryUpdate(obj, meta)
		if err != nil {
			return err
		}

		index := uint64(0)
		ttl := uint64(0)
		if node != nil {
			index = node.ModifiedIndex
			if node.TTL != 0 {
				ttl = uint64(node.TTL)
			}
			if node.Expiration != nil && ttl == 0 {
				ttl = 1
			}
		} else if res != nil {
			index = res.EtcdIndex
		}

		if newTTL != nil {
			if ttl != 0 && *newTTL == 0 {
				// TODO: remove this after we have verified this is no longer an issue
				glog.V(4).Infof("GuaranteedUpdate is clearing TTL for %q, may not be intentional", key)
			}
			ttl = *newTTL
		}

		data, err := h.codec.Encode(ret)
		if err != nil {
			return err
		}

		// First time this key has been used, try creating new value.
		if index == 0 {
			startTime := time.Now()
			response, err := h.client.Create(key, string(data), ttl)
			metrics.RecordEtcdRequestLatency("create", getTypeName(ptrToType), startTime)
			if IsEtcdNodeExist(err) {
				continue
			}
			_, _, err = h.extractObj(response, err, ptrToType, false, false)
			return err
		}

		if string(data) == origBody {
			return nil
		}

		startTime := time.Now()
		// Swap origBody with data, if origBody is the latest etcd data.
		response, err := h.client.CompareAndSwap(key, string(data), ttl, origBody, index)
		metrics.RecordEtcdRequestLatency("compareAndSwap", getTypeName(ptrToType), startTime)
		if IsEtcdTestFailed(err) {
			// Try again.
			continue
		}
		_, _, err = h.extractObj(response, err, ptrToType, false, false)
		return err
	}
}