1 /* 2 * 3 * Copyright 2019 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 // Package xdsclient implements a full fledged gRPC client for the xDS API used 20 // by the xds resolver and balancer implementations. 21 package xdsclient 22 23 import ( 24 "google.golang.org/grpc/internal/xds/bootstrap" 25 "google.golang.org/grpc/xds/internal/xdsclient/load" 26 "google.golang.org/grpc/xds/internal/xdsclient/xdsresource" 27 ) 28 29 // XDSClient is a full fledged gRPC client which queries a set of discovery APIs 30 // (collectively termed as xDS) on a remote management server, to discover 31 // various dynamic resources. 32 type XDSClient interface { 33 // WatchResource uses xDS to discover the resource associated with the 34 // provided resource name. The resource type implementation determines how 35 // xDS requests are sent out and how responses are deserialized and 36 // validated. Upon receipt of a response from the management server, an 37 // appropriate callback on the watcher is invoked. 38 // 39 // Most callers will not have a need to use this API directly. They will 40 // instead use a resource-type-specific wrapper API provided by the relevant 41 // resource type implementation. 42 // 43 // 44 // During a race (e.g. an xDS response is received while the user is calling 45 // cancel()), there's a small window where the callback can be called after 46 // the watcher is canceled. Callers need to handle this case. 47 WatchResource(rType xdsresource.Type, resourceName string, watcher xdsresource.ResourceWatcher) (cancel func()) 48 49 // DumpResources returns the status of the xDS resources. Returns a map of 50 // resource type URLs to a map of resource names to resource state. 51 DumpResources() map[string]map[string]xdsresource.UpdateWithMD 52 53 ReportLoad(*bootstrap.ServerConfig) (*load.Store, func()) 54 55 BootstrapConfig() *bootstrap.Config 56 } 57