diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer_conn_wrappers.go')
-rw-r--r-- | vendor/google.golang.org/grpc/balancer_conn_wrappers.go | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go new file mode 100644 index 0000000..7233ade --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go | |||
@@ -0,0 +1,328 @@ | |||
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 grpc | ||
20 | |||
21 | import ( | ||
22 | "fmt" | ||
23 | "sync" | ||
24 | |||
25 | "google.golang.org/grpc/balancer" | ||
26 | "google.golang.org/grpc/connectivity" | ||
27 | "google.golang.org/grpc/grpclog" | ||
28 | "google.golang.org/grpc/resolver" | ||
29 | ) | ||
30 | |||
31 | // scStateUpdate contains the subConn and the new state it changed to. | ||
32 | type scStateUpdate struct { | ||
33 | sc balancer.SubConn | ||
34 | state connectivity.State | ||
35 | } | ||
36 | |||
37 | // scStateUpdateBuffer is an unbounded channel for scStateChangeTuple. | ||
38 | // TODO make a general purpose buffer that uses interface{}. | ||
39 | type scStateUpdateBuffer struct { | ||
40 | c chan *scStateUpdate | ||
41 | mu sync.Mutex | ||
42 | backlog []*scStateUpdate | ||
43 | } | ||
44 | |||
45 | func newSCStateUpdateBuffer() *scStateUpdateBuffer { | ||
46 | return &scStateUpdateBuffer{ | ||
47 | c: make(chan *scStateUpdate, 1), | ||
48 | } | ||
49 | } | ||
50 | |||
51 | func (b *scStateUpdateBuffer) put(t *scStateUpdate) { | ||
52 | b.mu.Lock() | ||
53 | defer b.mu.Unlock() | ||
54 | if len(b.backlog) == 0 { | ||
55 | select { | ||
56 | case b.c <- t: | ||
57 | return | ||
58 | default: | ||
59 | } | ||
60 | } | ||
61 | b.backlog = append(b.backlog, t) | ||
62 | } | ||
63 | |||
64 | func (b *scStateUpdateBuffer) load() { | ||
65 | b.mu.Lock() | ||
66 | defer b.mu.Unlock() | ||
67 | if len(b.backlog) > 0 { | ||
68 | select { | ||
69 | case b.c <- b.backlog[0]: | ||
70 | b.backlog[0] = nil | ||
71 | b.backlog = b.backlog[1:] | ||
72 | default: | ||
73 | } | ||
74 | } | ||
75 | } | ||
76 | |||
77 | // get returns the channel that the scStateUpdate will be sent to. | ||
78 | // | ||
79 | // Upon receiving, the caller should call load to send another | ||
80 | // scStateChangeTuple onto the channel if there is any. | ||
81 | func (b *scStateUpdateBuffer) get() <-chan *scStateUpdate { | ||
82 | return b.c | ||
83 | } | ||
84 | |||
85 | // resolverUpdate contains the new resolved addresses or error if there's | ||
86 | // any. | ||
87 | type resolverUpdate struct { | ||
88 | addrs []resolver.Address | ||
89 | err error | ||
90 | } | ||
91 | |||
92 | // ccBalancerWrapper is a wrapper on top of cc for balancers. | ||
93 | // It implements balancer.ClientConn interface. | ||
94 | type ccBalancerWrapper struct { | ||
95 | cc *ClientConn | ||
96 | balancer balancer.Balancer | ||
97 | stateChangeQueue *scStateUpdateBuffer | ||
98 | resolverUpdateCh chan *resolverUpdate | ||
99 | done chan struct{} | ||
100 | |||
101 | mu sync.Mutex | ||
102 | subConns map[*acBalancerWrapper]struct{} | ||
103 | } | ||
104 | |||
105 | func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper { | ||
106 | ccb := &ccBalancerWrapper{ | ||
107 | cc: cc, | ||
108 | stateChangeQueue: newSCStateUpdateBuffer(), | ||
109 | resolverUpdateCh: make(chan *resolverUpdate, 1), | ||
110 | done: make(chan struct{}), | ||
111 | subConns: make(map[*acBalancerWrapper]struct{}), | ||
112 | } | ||
113 | go ccb.watcher() | ||
114 | ccb.balancer = b.Build(ccb, bopts) | ||
115 | return ccb | ||
116 | } | ||
117 | |||
118 | // watcher balancer functions sequentially, so the balancer can be implemented | ||
119 | // lock-free. | ||
120 | func (ccb *ccBalancerWrapper) watcher() { | ||
121 | for { | ||
122 | select { | ||
123 | case t := <-ccb.stateChangeQueue.get(): | ||
124 | ccb.stateChangeQueue.load() | ||
125 | select { | ||
126 | case <-ccb.done: | ||
127 | ccb.balancer.Close() | ||
128 | return | ||
129 | default: | ||
130 | } | ||
131 | ccb.balancer.HandleSubConnStateChange(t.sc, t.state) | ||
132 | case t := <-ccb.resolverUpdateCh: | ||
133 | select { | ||
134 | case <-ccb.done: | ||
135 | ccb.balancer.Close() | ||
136 | return | ||
137 | default: | ||
138 | } | ||
139 | ccb.balancer.HandleResolvedAddrs(t.addrs, t.err) | ||
140 | case <-ccb.done: | ||
141 | } | ||
142 | |||
143 | select { | ||
144 | case <-ccb.done: | ||
145 | ccb.balancer.Close() | ||
146 | ccb.mu.Lock() | ||
147 | scs := ccb.subConns | ||
148 | ccb.subConns = nil | ||
149 | ccb.mu.Unlock() | ||
150 | for acbw := range scs { | ||
151 | ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain) | ||
152 | } | ||
153 | return | ||
154 | default: | ||
155 | } | ||
156 | } | ||
157 | } | ||
158 | |||
159 | func (ccb *ccBalancerWrapper) close() { | ||
160 | close(ccb.done) | ||
161 | } | ||
162 | |||
163 | func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State) { | ||
164 | // When updating addresses for a SubConn, if the address in use is not in | ||
165 | // the new addresses, the old ac will be tearDown() and a new ac will be | ||
166 | // created. tearDown() generates a state change with Shutdown state, we | ||
167 | // don't want the balancer to receive this state change. So before | ||
168 | // tearDown() on the old ac, ac.acbw (acWrapper) will be set to nil, and | ||
169 | // this function will be called with (nil, Shutdown). We don't need to call | ||
170 | // balancer method in this case. | ||
171 | if sc == nil { | ||
172 | return | ||
173 | } | ||
174 | ccb.stateChangeQueue.put(&scStateUpdate{ | ||
175 | sc: sc, | ||
176 | state: s, | ||
177 | }) | ||
178 | } | ||
179 | |||
180 | func (ccb *ccBalancerWrapper) handleResolvedAddrs(addrs []resolver.Address, err error) { | ||
181 | if ccb.cc.curBalancerName != grpclbName { | ||
182 | var containsGRPCLB bool | ||
183 | for _, a := range addrs { | ||
184 | if a.Type == resolver.GRPCLB { | ||
185 | containsGRPCLB = true | ||
186 | break | ||
187 | } | ||
188 | } | ||
189 | if containsGRPCLB { | ||
190 | // The current balancer is not grpclb, but addresses contain grpclb | ||
191 | // address. This means we failed to switch to grpclb, most likely | ||
192 | // because grpclb is not registered. Filter out all grpclb addresses | ||
193 | // from addrs before sending to balancer. | ||
194 | tempAddrs := make([]resolver.Address, 0, len(addrs)) | ||
195 | for _, a := range addrs { | ||
196 | if a.Type != resolver.GRPCLB { | ||
197 | tempAddrs = append(tempAddrs, a) | ||
198 | } | ||
199 | } | ||
200 | addrs = tempAddrs | ||
201 | } | ||
202 | } | ||
203 | select { | ||
204 | case <-ccb.resolverUpdateCh: | ||
205 | default: | ||
206 | } | ||
207 | ccb.resolverUpdateCh <- &resolverUpdate{ | ||
208 | addrs: addrs, | ||
209 | err: err, | ||
210 | } | ||
211 | } | ||
212 | |||
213 | func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) { | ||
214 | if len(addrs) <= 0 { | ||
215 | return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list") | ||
216 | } | ||
217 | ccb.mu.Lock() | ||
218 | defer ccb.mu.Unlock() | ||
219 | if ccb.subConns == nil { | ||
220 | return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed") | ||
221 | } | ||
222 | ac, err := ccb.cc.newAddrConn(addrs, opts) | ||
223 | if err != nil { | ||
224 | return nil, err | ||
225 | } | ||
226 | acbw := &acBalancerWrapper{ac: ac} | ||
227 | acbw.ac.mu.Lock() | ||
228 | ac.acbw = acbw | ||
229 | acbw.ac.mu.Unlock() | ||
230 | ccb.subConns[acbw] = struct{}{} | ||
231 | return acbw, nil | ||
232 | } | ||
233 | |||
234 | func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) { | ||
235 | acbw, ok := sc.(*acBalancerWrapper) | ||
236 | if !ok { | ||
237 | return | ||
238 | } | ||
239 | ccb.mu.Lock() | ||
240 | defer ccb.mu.Unlock() | ||
241 | if ccb.subConns == nil { | ||
242 | return | ||
243 | } | ||
244 | delete(ccb.subConns, acbw) | ||
245 | ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain) | ||
246 | } | ||
247 | |||
248 | func (ccb *ccBalancerWrapper) UpdateBalancerState(s connectivity.State, p balancer.Picker) { | ||
249 | ccb.mu.Lock() | ||
250 | defer ccb.mu.Unlock() | ||
251 | if ccb.subConns == nil { | ||
252 | return | ||
253 | } | ||
254 | // Update picker before updating state. Even though the ordering here does | ||
255 | // not matter, it can lead to multiple calls of Pick in the common start-up | ||
256 | // case where we wait for ready and then perform an RPC. If the picker is | ||
257 | // updated later, we could call the "connecting" picker when the state is | ||
258 | // updated, and then call the "ready" picker after the picker gets updated. | ||
259 | ccb.cc.blockingpicker.updatePicker(p) | ||
260 | ccb.cc.csMgr.updateState(s) | ||
261 | } | ||
262 | |||
263 | func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOption) { | ||
264 | ccb.cc.resolveNow(o) | ||
265 | } | ||
266 | |||
267 | func (ccb *ccBalancerWrapper) Target() string { | ||
268 | return ccb.cc.target | ||
269 | } | ||
270 | |||
271 | // acBalancerWrapper is a wrapper on top of ac for balancers. | ||
272 | // It implements balancer.SubConn interface. | ||
273 | type acBalancerWrapper struct { | ||
274 | mu sync.Mutex | ||
275 | ac *addrConn | ||
276 | } | ||
277 | |||
278 | func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) { | ||
279 | acbw.mu.Lock() | ||
280 | defer acbw.mu.Unlock() | ||
281 | if len(addrs) <= 0 { | ||
282 | acbw.ac.tearDown(errConnDrain) | ||
283 | return | ||
284 | } | ||
285 | if !acbw.ac.tryUpdateAddrs(addrs) { | ||
286 | cc := acbw.ac.cc | ||
287 | opts := acbw.ac.scopts | ||
288 | acbw.ac.mu.Lock() | ||
289 | // Set old ac.acbw to nil so the Shutdown state update will be ignored | ||
290 | // by balancer. | ||
291 | // | ||
292 | // TODO(bar) the state transition could be wrong when tearDown() old ac | ||
293 | // and creating new ac, fix the transition. | ||
294 | acbw.ac.acbw = nil | ||
295 | acbw.ac.mu.Unlock() | ||
296 | acState := acbw.ac.getState() | ||
297 | acbw.ac.tearDown(errConnDrain) | ||
298 | |||
299 | if acState == connectivity.Shutdown { | ||
300 | return | ||
301 | } | ||
302 | |||
303 | ac, err := cc.newAddrConn(addrs, opts) | ||
304 | if err != nil { | ||
305 | grpclog.Warningf("acBalancerWrapper: UpdateAddresses: failed to newAddrConn: %v", err) | ||
306 | return | ||
307 | } | ||
308 | acbw.ac = ac | ||
309 | ac.mu.Lock() | ||
310 | ac.acbw = acbw | ||
311 | ac.mu.Unlock() | ||
312 | if acState != connectivity.Idle { | ||
313 | ac.connect() | ||
314 | } | ||
315 | } | ||
316 | } | ||
317 | |||
318 | func (acbw *acBalancerWrapper) Connect() { | ||
319 | acbw.mu.Lock() | ||
320 | defer acbw.mu.Unlock() | ||
321 | acbw.ac.connect() | ||
322 | } | ||
323 | |||
324 | func (acbw *acBalancerWrapper) getAddrConn() *addrConn { | ||
325 | acbw.mu.Lock() | ||
326 | defer acbw.mu.Unlock() | ||
327 | return acbw.ac | ||
328 | } | ||