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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 | "encoding/json" | |
23 | "fmt" | |
24 | "strconv" | |
25 | "strings" | |
26 | "time" | |
27 | ||
28 | "google.golang.org/grpc/codes" | |
29 | "google.golang.org/grpc/grpclog" | |
30 | ) | |
31 | ||
32 | const maxInt = int(^uint(0) >> 1) | |
33 | ||
34 | // MethodConfig defines the configuration recommended by the service providers for a | |
35 | // particular method. | |
36 | // | |
37 | // Deprecated: Users should not use this struct. Service config should be received | |
38 | // through name resolver, as specified here | |
39 | // https://github.com/grpc/grpc/blob/master/doc/service_config.md | |
40 | type MethodConfig struct { | |
41 | // WaitForReady indicates whether RPCs sent to this method should wait until | |
42 | // the connection is ready by default (!failfast). The value specified via the | |
43 | // gRPC client API will override the value set here. | |
44 | WaitForReady *bool | |
45 | // Timeout is the default timeout for RPCs sent to this method. The actual | |
46 | // deadline used will be the minimum of the value specified here and the value | |
47 | // set by the application via the gRPC client API. If either one is not set, | |
48 | // then the other will be used. If neither is set, then the RPC has no deadline. | |
49 | Timeout *time.Duration | |
50 | // MaxReqSize is the maximum allowed payload size for an individual request in a | |
51 | // stream (client->server) in bytes. The size which is measured is the serialized | |
52 | // payload after per-message compression (but before stream compression) in bytes. | |
53 | // The actual value used is the minimum of the value specified here and the value set | |
54 | // by the application via the gRPC client API. If either one is not set, then the other | |
55 | // will be used. If neither is set, then the built-in default is used. | |
56 | MaxReqSize *int | |
57 | // MaxRespSize is the maximum allowed payload size for an individual response in a | |
58 | // stream (server->client) in bytes. | |
59 | MaxRespSize *int | |
60 | // RetryPolicy configures retry options for the method. | |
61 | retryPolicy *retryPolicy | |
62 | } | |
63 | ||
64 | // ServiceConfig is provided by the service provider and contains parameters for how | |
65 | // clients that connect to the service should behave. | |
66 | // | |
67 | // Deprecated: Users should not use this struct. Service config should be received | |
68 | // through name resolver, as specified here | |
69 | // https://github.com/grpc/grpc/blob/master/doc/service_config.md | |
70 | type ServiceConfig struct { | |
71 | // LB is the load balancer the service providers recommends. The balancer specified | |
72 | // via grpc.WithBalancer will override this. | |
73 | LB *string | |
74 | ||
75 | // Methods contains a map for the methods in this service. If there is an | |
76 | // exact match for a method (i.e. /service/method) in the map, use the | |
77 | // corresponding MethodConfig. If there's no exact match, look for the | |
78 | // default config for the service (/service/) and use the corresponding | |
79 | // MethodConfig if it exists. Otherwise, the method has no MethodConfig to | |
80 | // use. | |
81 | Methods map[string]MethodConfig | |
82 | ||
83 | // If a retryThrottlingPolicy is provided, gRPC will automatically throttle | |
84 | // retry attempts and hedged RPCs when the client’s ratio of failures to | |
85 | // successes exceeds a threshold. | |
86 | // | |
87 | // For each server name, the gRPC client will maintain a token_count which is | |
88 | // initially set to maxTokens, and can take values between 0 and maxTokens. | |
89 | // | |
90 | // Every outgoing RPC (regardless of service or method invoked) will change | |
91 | // token_count as follows: | |
92 | // | |
93 | // - Every failed RPC will decrement the token_count by 1. | |
94 | // - Every successful RPC will increment the token_count by tokenRatio. | |
95 | // | |
96 | // If token_count is less than or equal to maxTokens / 2, then RPCs will not | |
97 | // be retried and hedged RPCs will not be sent. | |
98 | retryThrottling *retryThrottlingPolicy | |
99 | // healthCheckConfig must be set as one of the requirement to enable LB channel | |
100 | // health check. | |
101 | healthCheckConfig *healthCheckConfig | |
102 | } | |
103 | ||
104 | // healthCheckConfig defines the go-native version of the LB channel health check config. | |
105 | type healthCheckConfig struct { | |
106 | // serviceName is the service name to use in the health-checking request. | |
107 | ServiceName string | |
108 | } | |
109 | ||
110 | // retryPolicy defines the go-native version of the retry policy defined by the | |
111 | // service config here: | |
112 | // https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config | |
113 | type retryPolicy struct { | |
114 | // MaxAttempts is the maximum number of attempts, including the original RPC. | |
115 | // | |
116 | // This field is required and must be two or greater. | |
117 | maxAttempts int | |
118 | ||
119 | // Exponential backoff parameters. The initial retry attempt will occur at | |
120 | // random(0, initialBackoffMS). In general, the nth attempt will occur at | |
121 | // random(0, | |
122 | // min(initialBackoffMS*backoffMultiplier**(n-1), maxBackoffMS)). | |
123 | // | |
124 | // These fields are required and must be greater than zero. | |
125 | initialBackoff time.Duration | |
126 | maxBackoff time.Duration | |
127 | backoffMultiplier float64 | |
128 | ||
129 | // The set of status codes which may be retried. | |
130 | // | |
131 | // Status codes are specified as strings, e.g., "UNAVAILABLE". | |
132 | // | |
133 | // This field is required and must be non-empty. | |
134 | // Note: a set is used to store this for easy lookup. | |
135 | retryableStatusCodes map[codes.Code]bool | |
136 | } | |
137 | ||
138 | type jsonRetryPolicy struct { | |
139 | MaxAttempts int | |
140 | InitialBackoff string | |
141 | MaxBackoff string | |
142 | BackoffMultiplier float64 | |
143 | RetryableStatusCodes []codes.Code | |
144 | } | |
145 | ||
146 | // retryThrottlingPolicy defines the go-native version of the retry throttling | |
147 | // policy defined by the service config here: | |
148 | // https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config | |
149 | type retryThrottlingPolicy struct { | |
150 | // The number of tokens starts at maxTokens. The token_count will always be | |
151 | // between 0 and maxTokens. | |
152 | // | |
153 | // This field is required and must be greater than zero. | |
154 | MaxTokens float64 | |
155 | // The amount of tokens to add on each successful RPC. Typically this will | |
156 | // be some number between 0 and 1, e.g., 0.1. | |
157 | // | |
158 | // This field is required and must be greater than zero. Up to 3 decimal | |
159 | // places are supported. | |
160 | TokenRatio float64 | |
161 | } | |
162 | ||
163 | func parseDuration(s *string) (*time.Duration, error) { | |
164 | if s == nil { | |
165 | return nil, nil | |
166 | } | |
167 | if !strings.HasSuffix(*s, "s") { | |
168 | return nil, fmt.Errorf("malformed duration %q", *s) | |
169 | } | |
170 | ss := strings.SplitN((*s)[:len(*s)-1], ".", 3) | |
171 | if len(ss) > 2 { | |
172 | return nil, fmt.Errorf("malformed duration %q", *s) | |
173 | } | |
174 | // hasDigits is set if either the whole or fractional part of the number is | |
175 | // present, since both are optional but one is required. | |
176 | hasDigits := false | |
177 | var d time.Duration | |
178 | if len(ss[0]) > 0 { | |
179 | i, err := strconv.ParseInt(ss[0], 10, 32) | |
180 | if err != nil { | |
181 | return nil, fmt.Errorf("malformed duration %q: %v", *s, err) | |
182 | } | |
183 | d = time.Duration(i) * time.Second | |
184 | hasDigits = true | |
185 | } | |
186 | if len(ss) == 2 && len(ss[1]) > 0 { | |
187 | if len(ss[1]) > 9 { | |
188 | return nil, fmt.Errorf("malformed duration %q", *s) | |
189 | } | |
190 | f, err := strconv.ParseInt(ss[1], 10, 64) | |
191 | if err != nil { | |
192 | return nil, fmt.Errorf("malformed duration %q: %v", *s, err) | |
193 | } | |
194 | for i := 9; i > len(ss[1]); i-- { | |
195 | f *= 10 | |
196 | } | |
197 | d += time.Duration(f) | |
198 | hasDigits = true | |
199 | } | |
200 | if !hasDigits { | |
201 | return nil, fmt.Errorf("malformed duration %q", *s) | |
202 | } | |
203 | ||
204 | return &d, nil | |
205 | } | |
206 | ||
207 | type jsonName struct { | |
208 | Service *string | |
209 | Method *string | |
210 | } | |
211 | ||
212 | func (j jsonName) generatePath() (string, bool) { | |
213 | if j.Service == nil { | |
214 | return "", false | |
215 | } | |
216 | res := "/" + *j.Service + "/" | |
217 | if j.Method != nil { | |
218 | res += *j.Method | |
219 | } | |
220 | return res, true | |
221 | } | |
222 | ||
223 | // TODO(lyuxuan): delete this struct after cleaning up old service config implementation. | |
224 | type jsonMC struct { | |
225 | Name *[]jsonName | |
226 | WaitForReady *bool | |
227 | Timeout *string | |
228 | MaxRequestMessageBytes *int64 | |
229 | MaxResponseMessageBytes *int64 | |
230 | RetryPolicy *jsonRetryPolicy | |
231 | } | |
232 | ||
233 | // TODO(lyuxuan): delete this struct after cleaning up old service config implementation. | |
234 | type jsonSC struct { | |
235 | LoadBalancingPolicy *string | |
236 | MethodConfig *[]jsonMC | |
237 | RetryThrottling *retryThrottlingPolicy | |
238 | HealthCheckConfig *healthCheckConfig | |
239 | } | |
240 | ||
241 | func parseServiceConfig(js string) (ServiceConfig, error) { | |
242 | if len(js) == 0 { | |
243 | return ServiceConfig{}, fmt.Errorf("no JSON service config provided") | |
244 | } | |
245 | var rsc jsonSC | |
246 | err := json.Unmarshal([]byte(js), &rsc) | |
247 | if err != nil { | |
248 | grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err) | |
249 | return ServiceConfig{}, err | |
250 | } | |
251 | sc := ServiceConfig{ | |
252 | LB: rsc.LoadBalancingPolicy, | |
253 | Methods: make(map[string]MethodConfig), | |
254 | retryThrottling: rsc.RetryThrottling, | |
255 | healthCheckConfig: rsc.HealthCheckConfig, | |
256 | } | |
257 | if rsc.MethodConfig == nil { | |
258 | return sc, nil | |
259 | } | |
260 | ||
261 | for _, m := range *rsc.MethodConfig { | |
262 | if m.Name == nil { | |
263 | continue | |
264 | } | |
265 | d, err := parseDuration(m.Timeout) | |
266 | if err != nil { | |
267 | grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err) | |
268 | return ServiceConfig{}, err | |
269 | } | |
270 | ||
271 | mc := MethodConfig{ | |
272 | WaitForReady: m.WaitForReady, | |
273 | Timeout: d, | |
274 | } | |
275 | if mc.retryPolicy, err = convertRetryPolicy(m.RetryPolicy); err != nil { | |
276 | grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err) | |
277 | return ServiceConfig{}, err | |
278 | } | |
279 | if m.MaxRequestMessageBytes != nil { | |
280 | if *m.MaxRequestMessageBytes > int64(maxInt) { | |
281 | mc.MaxReqSize = newInt(maxInt) | |
282 | } else { | |
283 | mc.MaxReqSize = newInt(int(*m.MaxRequestMessageBytes)) | |
284 | } | |
285 | } | |
286 | if m.MaxResponseMessageBytes != nil { | |
287 | if *m.MaxResponseMessageBytes > int64(maxInt) { | |
288 | mc.MaxRespSize = newInt(maxInt) | |
289 | } else { | |
290 | mc.MaxRespSize = newInt(int(*m.MaxResponseMessageBytes)) | |
291 | } | |
292 | } | |
293 | for _, n := range *m.Name { | |
294 | if path, valid := n.generatePath(); valid { | |
295 | sc.Methods[path] = mc | |
296 | } | |
297 | } | |
298 | } | |
299 | ||
300 | if sc.retryThrottling != nil { | |
301 | if sc.retryThrottling.MaxTokens <= 0 || | |
302 | sc.retryThrottling.MaxTokens >= 1000 || | |
303 | sc.retryThrottling.TokenRatio <= 0 { | |
304 | // Illegal throttling config; disable throttling. | |
305 | sc.retryThrottling = nil | |
306 | } | |
307 | } | |
308 | return sc, nil | |
309 | } | |
310 | ||
311 | func convertRetryPolicy(jrp *jsonRetryPolicy) (p *retryPolicy, err error) { | |
312 | if jrp == nil { | |
313 | return nil, nil | |
314 | } | |
315 | ib, err := parseDuration(&jrp.InitialBackoff) | |
316 | if err != nil { | |
317 | return nil, err | |
318 | } | |
319 | mb, err := parseDuration(&jrp.MaxBackoff) | |
320 | if err != nil { | |
321 | return nil, err | |
322 | } | |
323 | ||
324 | if jrp.MaxAttempts <= 1 || | |
325 | *ib <= 0 || | |
326 | *mb <= 0 || | |
327 | jrp.BackoffMultiplier <= 0 || | |
328 | len(jrp.RetryableStatusCodes) == 0 { | |
329 | grpclog.Warningf("grpc: ignoring retry policy %v due to illegal configuration", jrp) | |
330 | return nil, nil | |
331 | } | |
332 | ||
333 | rp := &retryPolicy{ | |
334 | maxAttempts: jrp.MaxAttempts, | |
335 | initialBackoff: *ib, | |
336 | maxBackoff: *mb, | |
337 | backoffMultiplier: jrp.BackoffMultiplier, | |
338 | retryableStatusCodes: make(map[codes.Code]bool), | |
339 | } | |
340 | if rp.maxAttempts > 5 { | |
341 | // TODO(retry): Make the max maxAttempts configurable. | |
342 | rp.maxAttempts = 5 | |
343 | } | |
344 | for _, code := range jrp.RetryableStatusCodes { | |
345 | rp.retryableStatusCodes[code] = true | |
346 | } | |
347 | return rp, nil | |
348 | } | |
349 | ||
350 | func min(a, b *int) *int { | |
351 | if *a < *b { | |
352 | return a | |
353 | } | |
354 | return b | |
355 | } | |
356 | ||
357 | func getMaxSize(mcMax, doptMax *int, defaultVal int) *int { | |
358 | if mcMax == nil && doptMax == nil { | |
359 | return &defaultVal | |
360 | } | |
361 | if mcMax != nil && doptMax != nil { | |
362 | return min(mcMax, doptMax) | |
363 | } | |
364 | if mcMax != nil { | |
365 | return mcMax | |
366 | } | |
367 | return doptMax | |
368 | } | |
369 | ||
370 | func newInt(b int) *int { | |
371 | return &b | |
372 | } |