unix.go (2216B)
1 /* 2 * 3 * Copyright 2020 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 unix implements a resolver for unix targets. 20 package unix 21 22 import ( 23 "fmt" 24 25 "google.golang.org/grpc/internal/transport/networktype" 26 "google.golang.org/grpc/resolver" 27 ) 28 29 const unixScheme = "unix" 30 const unixAbstractScheme = "unix-abstract" 31 32 type builder struct { 33 scheme string 34 } 35 36 func (b *builder) Build(target resolver.Target, cc resolver.ClientConn, _ resolver.BuildOptions) (resolver.Resolver, error) { 37 if target.URL.Host != "" { 38 return nil, fmt.Errorf("invalid (non-empty) authority: %v", target.URL.Host) 39 } 40 41 // gRPC was parsing the dial target manually before PR #4817, and we 42 // switched to using url.Parse() in that PR. To avoid breaking existing 43 // resolver implementations we ended up stripping the leading "/" from the 44 // endpoint. This obviously does not work for the "unix" scheme. Hence we 45 // end up using the parsed URL instead. 46 endpoint := target.URL.Path 47 if endpoint == "" { 48 endpoint = target.URL.Opaque 49 } 50 addr := resolver.Address{Addr: endpoint} 51 if b.scheme == unixAbstractScheme { 52 // We can not prepend \0 as c++ gRPC does, as in Golang '@' is used to signify we do 53 // not want trailing \0 in address. 54 addr.Addr = "@" + addr.Addr 55 } 56 cc.UpdateState(resolver.State{Addresses: []resolver.Address{networktype.Set(addr, "unix")}}) 57 return &nopResolver{}, nil 58 } 59 60 func (b *builder) Scheme() string { 61 return b.scheme 62 } 63 64 type nopResolver struct { 65 } 66 67 func (*nopResolver) ResolveNow(resolver.ResolveNowOptions) {} 68 69 func (*nopResolver) Close() {} 70 71 func init() { 72 resolver.Register(&builder{scheme: unixScheme}) 73 resolver.Register(&builder{scheme: unixAbstractScheme}) 74 }