passthrough.go (1702B)
1 /* 2 * 3 * Copyright 2017 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 passthrough implements a pass-through resolver. It sends the target 20 // name without scheme back to gRPC as resolved address. 21 package passthrough 22 23 import ( 24 "errors" 25 26 "google.golang.org/grpc/resolver" 27 ) 28 29 const scheme = "passthrough" 30 31 type passthroughBuilder struct{} 32 33 func (*passthroughBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) { 34 if target.Endpoint() == "" && opts.Dialer == nil { 35 return nil, errors.New("passthrough: received empty target in Build()") 36 } 37 r := &passthroughResolver{ 38 target: target, 39 cc: cc, 40 } 41 r.start() 42 return r, nil 43 } 44 45 func (*passthroughBuilder) Scheme() string { 46 return scheme 47 } 48 49 type passthroughResolver struct { 50 target resolver.Target 51 cc resolver.ClientConn 52 } 53 54 func (r *passthroughResolver) start() { 55 r.cc.UpdateState(resolver.State{Addresses: []resolver.Address{{Addr: r.target.Endpoint()}}}) 56 } 57 58 func (*passthroughResolver) ResolveNow(o resolver.ResolveNowOptions) {} 59 60 func (*passthroughResolver) Close() {} 61 62 func init() { 63 resolver.Register(&passthroughBuilder{}) 64 }