/* * * Copyright 2014 gRPC authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ // Package naming defines the naming API and related data structures for gRPC. // The interface is EXPERIMENTAL and may be suject to change. package naming // Operation defines the corresponding operations for a name resolution change. type Operation uint8 const ( // Add indicates a new address is added. Add Operation = iota // Delete indicates an exisiting address is deleted. Delete ) // Update defines a name resolution update. Notice that it is not valid having both // empty string Addr and nil Metadata in an Update. type Update struct { // Op indicates the operation of the update. Op Operation // Addr is the updated address. It is empty string if there is no address update. Addr string // Metadata is the updated metadata. It is nil if there is no metadata update. // Metadata is not required for a custom naming implementation. Metadata interface{} } // Resolver creates a Watcher for a target to track its resolution changes. type Resolver interface { // Resolve creates a Watcher for target. Resolve(target string) (Watcher, error) } // Watcher watches for the updates on the specified target. type Watcher interface { // Next blocks until an update or error happens. It may return one or more // updates. The first call should get the full set of the results. It should // return an error if and only if Watcher cannot recover. Next() ([]*Update, error) // Close closes the Watcher. Close() }