Kent Hagerman | 1e9061e | 2019-05-21 16:01:21 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2019-present Open Networking Foundation |
| 3 | |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package afrouter |
| 18 | |
| 19 | import ( |
| 20 | "context" |
Scott Baker | c69d4dc | 2019-08-09 12:25:46 -0700 | [diff] [blame^] | 21 | "encoding/hex" |
Kent Hagerman | 1e9061e | 2019-05-21 16:01:21 -0400 | [diff] [blame] | 22 | "errors" |
| 23 | "github.com/opencord/voltha-go/common/log" |
| 24 | "google.golang.org/grpc" |
| 25 | "google.golang.org/grpc/metadata" |
| 26 | "sort" |
| 27 | "sync" |
| 28 | ) |
| 29 | |
| 30 | type streams struct { |
| 31 | mutex sync.Mutex |
| 32 | activeStream *stream |
| 33 | streams map[string]*stream |
| 34 | sortedStreams []*stream |
| 35 | } |
| 36 | |
| 37 | type stream struct { |
| 38 | stream grpc.ClientStream |
| 39 | ctx context.Context |
| 40 | cancel context.CancelFunc |
| 41 | ok2Close chan struct{} |
| 42 | c2sReturn chan error |
| 43 | s2cReturn error |
| 44 | } |
| 45 | |
| 46 | func (s *streams) clientCancel() { |
| 47 | for _, strm := range s.streams { |
| 48 | if strm != nil { |
| 49 | strm.cancel() |
| 50 | } |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | func (s *streams) closeSend() { |
| 55 | for _, strm := range s.streams { |
| 56 | if strm != nil { |
| 57 | <-strm.ok2Close |
| 58 | log.Debug("Closing southbound stream") |
| 59 | strm.stream.CloseSend() |
| 60 | } |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | func (s *streams) trailer() metadata.MD { |
| 65 | return s.activeStream.stream.Trailer() |
| 66 | } |
| 67 | |
| 68 | func (s *streams) getActive() *stream { |
| 69 | s.mutex.Lock() |
| 70 | defer s.mutex.Unlock() |
| 71 | return s.activeStream |
| 72 | } |
| 73 | |
| 74 | func (s *streams) setThenGetActive(strm *stream) *stream { |
| 75 | s.mutex.Lock() |
| 76 | defer s.mutex.Unlock() |
| 77 | if s.activeStream == nil { |
| 78 | s.activeStream = strm |
| 79 | } |
| 80 | return s.activeStream |
| 81 | } |
| 82 | |
| 83 | func (s *streams) forwardClientToServer(dst grpc.ServerStream, f *sbFrame) chan error { |
| 84 | fc2s := func(srcS *stream) { |
| 85 | for i := 0; ; i++ { |
| 86 | if err := srcS.stream.RecvMsg(f); err != nil { |
| 87 | if s.setThenGetActive(srcS) == srcS { |
| 88 | srcS.c2sReturn <- err // this can be io.EOF which is the success case |
| 89 | } else { |
| 90 | srcS.c2sReturn <- nil // Inactive responder |
| 91 | } |
| 92 | close(srcS.ok2Close) |
| 93 | break |
| 94 | } |
| 95 | if s.setThenGetActive(srcS) != srcS { |
| 96 | srcS.c2sReturn <- nil |
| 97 | continue |
| 98 | } |
| 99 | if i == 0 { |
| 100 | // This is a bit of a hack, but client to server headers are only readable after first client msg is |
| 101 | // received but must be written to server stream before the first msg is flushed. |
| 102 | // This is the only place to do it nicely. |
| 103 | md, err := srcS.stream.Header() |
| 104 | if err != nil { |
| 105 | srcS.c2sReturn <- err |
| 106 | break |
| 107 | } |
| 108 | // Update the metadata for the response. |
| 109 | if f.metaKey != NoMeta { |
| 110 | if f.metaVal == "" { |
| 111 | // We could also alsways just do this |
| 112 | md.Set(f.metaKey, f.backend.name) |
| 113 | } else { |
| 114 | md.Set(f.metaKey, f.metaVal) |
| 115 | } |
| 116 | } |
| 117 | if err := dst.SendHeader(md); err != nil { |
| 118 | srcS.c2sReturn <- err |
| 119 | break |
| 120 | } |
| 121 | } |
Scott Baker | c69d4dc | 2019-08-09 12:25:46 -0700 | [diff] [blame^] | 122 | log.Debugf("Northbound frame %s", hex.EncodeToString(f.payload)) |
Kent Hagerman | 1e9061e | 2019-05-21 16:01:21 -0400 | [diff] [blame] | 123 | if err := dst.SendMsg(f); err != nil { |
| 124 | srcS.c2sReturn <- err |
| 125 | break |
| 126 | } |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | // There should be AT LEAST one open stream at this point |
| 131 | // if there isn't its a grave error in the code and it will |
| 132 | // cause this thread to block here so check for it and |
| 133 | // don't let the lock up happen but report the error |
| 134 | ret := make(chan error, 1) |
| 135 | agg := make(chan *stream) |
| 136 | atLeastOne := false |
| 137 | for _, strm := range s.streams { |
| 138 | if strm != nil { |
| 139 | go fc2s(strm) |
| 140 | go func(s *stream) { // Wait on result and aggregate |
| 141 | r := <-s.c2sReturn // got the return code |
| 142 | if r == nil { |
| 143 | return // We're the redundant stream, just die |
| 144 | } |
| 145 | s.c2sReturn <- r // put it back to pass it along |
| 146 | agg <- s // send the stream to the aggregator |
| 147 | }(strm) |
| 148 | atLeastOne = true |
| 149 | } |
| 150 | } |
| 151 | if atLeastOne == true { |
| 152 | go func() { // Wait on aggregated result |
| 153 | s := <-agg |
| 154 | ret <- <-s.c2sReturn |
| 155 | }() |
| 156 | } else { |
| 157 | err := errors.New("There are no open streams. Unable to forward message.") |
| 158 | log.Error(err) |
| 159 | ret <- err |
| 160 | } |
| 161 | return ret |
| 162 | } |
| 163 | |
| 164 | func (s *streams) sendAll(f *nbFrame) error { |
| 165 | var rtrn error |
| 166 | |
| 167 | atLeastOne := false |
| 168 | for _, strm := range s.sortedStreams { |
| 169 | if strm != nil { |
| 170 | if err := strm.stream.SendMsg(f); err != nil { |
| 171 | log.Debugf("Error on SendMsg: %s", err.Error()) |
| 172 | strm.s2cReturn = err |
| 173 | } |
| 174 | atLeastOne = true |
| 175 | } else { |
| 176 | log.Debugf("Nil stream") |
| 177 | } |
| 178 | } |
| 179 | // If one of the streams succeeded, declare success |
| 180 | // if none did pick an error and return it. |
| 181 | if atLeastOne == true { |
| 182 | for _, strm := range s.sortedStreams { |
| 183 | if strm != nil { |
| 184 | rtrn = strm.s2cReturn |
| 185 | if rtrn == nil { |
| 186 | return rtrn |
| 187 | } |
| 188 | } |
| 189 | } |
| 190 | return rtrn |
| 191 | } else { |
| 192 | rtrn = errors.New("There are no open streams, this should never happen") |
| 193 | log.Error(rtrn) |
| 194 | } |
| 195 | return rtrn |
| 196 | } |
| 197 | |
| 198 | func (s *streams) forwardServerToClient(src grpc.ServerStream, f *nbFrame) chan error { |
| 199 | ret := make(chan error, 1) |
| 200 | go func() { |
| 201 | // The frame buffer already has the results of a first |
| 202 | // RecvMsg in it so the first thing to do is to |
| 203 | // send it to the list of client streams and only |
| 204 | // then read some more. |
| 205 | for i := 0; ; i++ { |
| 206 | // Send the message to each of the backend streams |
| 207 | if err := s.sendAll(f); err != nil { |
| 208 | ret <- err |
| 209 | log.Debugf("SendAll failed %s", err.Error()) |
| 210 | break |
| 211 | } |
Scott Baker | c69d4dc | 2019-08-09 12:25:46 -0700 | [diff] [blame^] | 212 | log.Debugf("Southbound frame %s", hex.EncodeToString(f.payload)) |
Kent Hagerman | 1e9061e | 2019-05-21 16:01:21 -0400 | [diff] [blame] | 213 | if err := src.RecvMsg(f); err != nil { |
| 214 | ret <- err // this can be io.EOF which is happy case |
| 215 | break |
| 216 | } |
| 217 | } |
| 218 | }() |
| 219 | return ret |
| 220 | } |
| 221 | |
| 222 | func (s *streams) sortStreams() { |
| 223 | var tmpKeys []string |
| 224 | for k := range s.streams { |
| 225 | tmpKeys = append(tmpKeys, k) |
| 226 | } |
| 227 | sort.Strings(tmpKeys) |
| 228 | for _, v := range tmpKeys { |
| 229 | s.sortedStreams = append(s.sortedStreams, s.streams[v]) |
| 230 | } |
| 231 | } |