kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 1 | package sarama |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "fmt" |
| 7 | "sort" |
| 8 | "sync" |
| 9 | "time" |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 10 | |
| 11 | "github.com/rcrowley/go-metrics" |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 12 | ) |
| 13 | |
| 14 | // ErrClosedConsumerGroup is the error returned when a method is called on a consumer group that has been closed. |
| 15 | var ErrClosedConsumerGroup = errors.New("kafka: tried to use a consumer group that was closed") |
| 16 | |
| 17 | // ConsumerGroup is responsible for dividing up processing of topics and partitions |
| 18 | // over a collection of processes (the members of the consumer group). |
| 19 | type ConsumerGroup interface { |
| 20 | // Consume joins a cluster of consumers for a given list of topics and |
| 21 | // starts a blocking ConsumerGroupSession through the ConsumerGroupHandler. |
| 22 | // |
| 23 | // The life-cycle of a session is represented by the following steps: |
| 24 | // |
| 25 | // 1. The consumers join the group (as explained in https://kafka.apache.org/documentation/#intro_consumers) |
| 26 | // and is assigned their "fair share" of partitions, aka 'claims'. |
| 27 | // 2. Before processing starts, the handler's Setup() hook is called to notify the user |
| 28 | // of the claims and allow any necessary preparation or alteration of state. |
| 29 | // 3. For each of the assigned claims the handler's ConsumeClaim() function is then called |
| 30 | // in a separate goroutine which requires it to be thread-safe. Any state must be carefully protected |
| 31 | // from concurrent reads/writes. |
| 32 | // 4. The session will persist until one of the ConsumeClaim() functions exits. This can be either when the |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 33 | // parent context is canceled or when a server-side rebalance cycle is initiated. |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 34 | // 5. Once all the ConsumeClaim() loops have exited, the handler's Cleanup() hook is called |
| 35 | // to allow the user to perform any final tasks before a rebalance. |
| 36 | // 6. Finally, marked offsets are committed one last time before claims are released. |
| 37 | // |
| 38 | // Please note, that once a rebalance is triggered, sessions must be completed within |
| 39 | // Config.Consumer.Group.Rebalance.Timeout. This means that ConsumeClaim() functions must exit |
| 40 | // as quickly as possible to allow time for Cleanup() and the final offset commit. If the timeout |
| 41 | // is exceeded, the consumer will be removed from the group by Kafka, which will cause offset |
| 42 | // commit failures. |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 43 | // This method should be called inside an infinite loop, when a |
| 44 | // server-side rebalance happens, the consumer session will need to be |
| 45 | // recreated to get the new claims. |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 46 | Consume(ctx context.Context, topics []string, handler ConsumerGroupHandler) error |
| 47 | |
| 48 | // Errors returns a read channel of errors that occurred during the consumer life-cycle. |
| 49 | // By default, errors are logged and not returned over this channel. |
| 50 | // If you want to implement any custom error handling, set your config's |
| 51 | // Consumer.Return.Errors setting to true, and read from this channel. |
| 52 | Errors() <-chan error |
| 53 | |
| 54 | // Close stops the ConsumerGroup and detaches any running sessions. It is required to call |
| 55 | // this function before the object passes out of scope, as it will otherwise leak memory. |
| 56 | Close() error |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 57 | |
| 58 | // Pause suspends fetching from the requested partitions. Future calls to the broker will not return any |
| 59 | // records from these partitions until they have been resumed using Resume()/ResumeAll(). |
| 60 | // Note that this method does not affect partition subscription. |
| 61 | // In particular, it does not cause a group rebalance when automatic assignment is used. |
| 62 | Pause(partitions map[string][]int32) |
| 63 | |
| 64 | // Resume resumes specified partitions which have been paused with Pause()/PauseAll(). |
| 65 | // New calls to the broker will return records from these partitions if there are any to be fetched. |
| 66 | Resume(partitions map[string][]int32) |
| 67 | |
| 68 | // Pause suspends fetching from all partitions. Future calls to the broker will not return any |
| 69 | // records from these partitions until they have been resumed using Resume()/ResumeAll(). |
| 70 | // Note that this method does not affect partition subscription. |
| 71 | // In particular, it does not cause a group rebalance when automatic assignment is used. |
| 72 | PauseAll() |
| 73 | |
| 74 | // Resume resumes all partitions which have been paused with Pause()/PauseAll(). |
| 75 | // New calls to the broker will return records from these partitions if there are any to be fetched. |
| 76 | ResumeAll() |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 77 | } |
| 78 | |
| 79 | type consumerGroup struct { |
| 80 | client Client |
| 81 | |
| 82 | config *Config |
| 83 | consumer Consumer |
| 84 | groupID string |
| 85 | memberID string |
| 86 | errors chan error |
| 87 | |
| 88 | lock sync.Mutex |
| 89 | closed chan none |
| 90 | closeOnce sync.Once |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 91 | |
| 92 | userData []byte |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 93 | } |
| 94 | |
| 95 | // NewConsumerGroup creates a new consumer group the given broker addresses and configuration. |
| 96 | func NewConsumerGroup(addrs []string, groupID string, config *Config) (ConsumerGroup, error) { |
| 97 | client, err := NewClient(addrs, config) |
| 98 | if err != nil { |
| 99 | return nil, err |
| 100 | } |
| 101 | |
| 102 | c, err := newConsumerGroup(groupID, client) |
| 103 | if err != nil { |
| 104 | _ = client.Close() |
| 105 | } |
| 106 | return c, err |
| 107 | } |
| 108 | |
| 109 | // NewConsumerGroupFromClient creates a new consumer group using the given client. It is still |
| 110 | // necessary to call Close() on the underlying client when shutting down this consumer. |
| 111 | // PLEASE NOTE: consumer groups can only re-use but not share clients. |
| 112 | func NewConsumerGroupFromClient(groupID string, client Client) (ConsumerGroup, error) { |
| 113 | // For clients passed in by the client, ensure we don't |
| 114 | // call Close() on it. |
| 115 | cli := &nopCloserClient{client} |
| 116 | return newConsumerGroup(groupID, cli) |
| 117 | } |
| 118 | |
| 119 | func newConsumerGroup(groupID string, client Client) (ConsumerGroup, error) { |
| 120 | config := client.Config() |
| 121 | if !config.Version.IsAtLeast(V0_10_2_0) { |
| 122 | return nil, ConfigurationError("consumer groups require Version to be >= V0_10_2_0") |
| 123 | } |
| 124 | |
| 125 | consumer, err := NewConsumerFromClient(client) |
| 126 | if err != nil { |
| 127 | return nil, err |
| 128 | } |
| 129 | |
| 130 | return &consumerGroup{ |
| 131 | client: client, |
| 132 | consumer: consumer, |
| 133 | config: config, |
| 134 | groupID: groupID, |
| 135 | errors: make(chan error, config.ChannelBufferSize), |
| 136 | closed: make(chan none), |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 137 | userData: config.Consumer.Group.Member.UserData, |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 138 | }, nil |
| 139 | } |
| 140 | |
| 141 | // Errors implements ConsumerGroup. |
| 142 | func (c *consumerGroup) Errors() <-chan error { return c.errors } |
| 143 | |
| 144 | // Close implements ConsumerGroup. |
| 145 | func (c *consumerGroup) Close() (err error) { |
| 146 | c.closeOnce.Do(func() { |
| 147 | close(c.closed) |
| 148 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 149 | // leave group |
| 150 | if e := c.leave(); e != nil { |
| 151 | err = e |
| 152 | } |
| 153 | |
| 154 | // drain errors |
| 155 | go func() { |
| 156 | close(c.errors) |
| 157 | }() |
| 158 | for e := range c.errors { |
| 159 | err = e |
| 160 | } |
| 161 | |
| 162 | if e := c.client.Close(); e != nil { |
| 163 | err = e |
| 164 | } |
| 165 | }) |
| 166 | return |
| 167 | } |
| 168 | |
| 169 | // Consume implements ConsumerGroup. |
| 170 | func (c *consumerGroup) Consume(ctx context.Context, topics []string, handler ConsumerGroupHandler) error { |
| 171 | // Ensure group is not closed |
| 172 | select { |
| 173 | case <-c.closed: |
| 174 | return ErrClosedConsumerGroup |
| 175 | default: |
| 176 | } |
| 177 | |
| 178 | c.lock.Lock() |
| 179 | defer c.lock.Unlock() |
| 180 | |
| 181 | // Quick exit when no topics are provided |
| 182 | if len(topics) == 0 { |
| 183 | return fmt.Errorf("no topics provided") |
| 184 | } |
| 185 | |
| 186 | // Refresh metadata for requested topics |
| 187 | if err := c.client.RefreshMetadata(topics...); err != nil { |
| 188 | return err |
| 189 | } |
| 190 | |
| 191 | // Init session |
| 192 | sess, err := c.newSession(ctx, topics, handler, c.config.Consumer.Group.Rebalance.Retry.Max) |
| 193 | if err == ErrClosedClient { |
| 194 | return ErrClosedConsumerGroup |
| 195 | } else if err != nil { |
| 196 | return err |
| 197 | } |
| 198 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 199 | // loop check topic partition numbers changed |
| 200 | // will trigger rebalance when any topic partitions number had changed |
| 201 | // avoid Consume function called again that will generate more than loopCheckPartitionNumbers coroutine |
| 202 | go c.loopCheckPartitionNumbers(topics, sess) |
| 203 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 204 | // Wait for session exit signal |
| 205 | <-sess.ctx.Done() |
| 206 | |
| 207 | // Gracefully release session claims |
| 208 | return sess.release(true) |
| 209 | } |
| 210 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 211 | // Pause implements ConsumerGroup. |
| 212 | func (c *consumerGroup) Pause(partitions map[string][]int32) { |
| 213 | c.consumer.Pause(partitions) |
| 214 | } |
| 215 | |
| 216 | // Resume implements ConsumerGroup. |
| 217 | func (c *consumerGroup) Resume(partitions map[string][]int32) { |
| 218 | c.consumer.Resume(partitions) |
| 219 | } |
| 220 | |
| 221 | // PauseAll implements ConsumerGroup. |
| 222 | func (c *consumerGroup) PauseAll() { |
| 223 | c.consumer.PauseAll() |
| 224 | } |
| 225 | |
| 226 | // ResumeAll implements ConsumerGroup. |
| 227 | func (c *consumerGroup) ResumeAll() { |
| 228 | c.consumer.ResumeAll() |
| 229 | } |
| 230 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 231 | func (c *consumerGroup) retryNewSession(ctx context.Context, topics []string, handler ConsumerGroupHandler, retries int, refreshCoordinator bool) (*consumerGroupSession, error) { |
| 232 | select { |
| 233 | case <-c.closed: |
| 234 | return nil, ErrClosedConsumerGroup |
| 235 | case <-time.After(c.config.Consumer.Group.Rebalance.Retry.Backoff): |
| 236 | } |
| 237 | |
| 238 | if refreshCoordinator { |
| 239 | err := c.client.RefreshCoordinator(c.groupID) |
| 240 | if err != nil { |
| 241 | return c.retryNewSession(ctx, topics, handler, retries, true) |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | return c.newSession(ctx, topics, handler, retries-1) |
| 246 | } |
| 247 | |
| 248 | func (c *consumerGroup) newSession(ctx context.Context, topics []string, handler ConsumerGroupHandler, retries int) (*consumerGroupSession, error) { |
| 249 | coordinator, err := c.client.Coordinator(c.groupID) |
| 250 | if err != nil { |
| 251 | if retries <= 0 { |
| 252 | return nil, err |
| 253 | } |
| 254 | |
| 255 | return c.retryNewSession(ctx, topics, handler, retries, true) |
| 256 | } |
| 257 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 258 | var ( |
| 259 | metricRegistry = c.config.MetricRegistry |
| 260 | consumerGroupJoinTotal metrics.Counter |
| 261 | consumerGroupJoinFailed metrics.Counter |
| 262 | consumerGroupSyncTotal metrics.Counter |
| 263 | consumerGroupSyncFailed metrics.Counter |
| 264 | ) |
| 265 | |
| 266 | if metricRegistry != nil { |
| 267 | consumerGroupJoinTotal = metrics.GetOrRegisterCounter(fmt.Sprintf("consumer-group-join-total-%s", c.groupID), metricRegistry) |
| 268 | consumerGroupJoinFailed = metrics.GetOrRegisterCounter(fmt.Sprintf("consumer-group-join-failed-%s", c.groupID), metricRegistry) |
| 269 | consumerGroupSyncTotal = metrics.GetOrRegisterCounter(fmt.Sprintf("consumer-group-sync-total-%s", c.groupID), metricRegistry) |
| 270 | consumerGroupSyncFailed = metrics.GetOrRegisterCounter(fmt.Sprintf("consumer-group-sync-failed-%s", c.groupID), metricRegistry) |
| 271 | } |
| 272 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 273 | // Join consumer group |
| 274 | join, err := c.joinGroupRequest(coordinator, topics) |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 275 | if consumerGroupJoinTotal != nil { |
| 276 | consumerGroupJoinTotal.Inc(1) |
| 277 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 278 | if err != nil { |
| 279 | _ = coordinator.Close() |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 280 | if consumerGroupJoinFailed != nil { |
| 281 | consumerGroupJoinFailed.Inc(1) |
| 282 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 283 | return nil, err |
| 284 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 285 | if join.Err != ErrNoError { |
| 286 | if consumerGroupJoinFailed != nil { |
| 287 | consumerGroupJoinFailed.Inc(1) |
| 288 | } |
| 289 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 290 | switch join.Err { |
| 291 | case ErrNoError: |
| 292 | c.memberID = join.MemberId |
| 293 | case ErrUnknownMemberId, ErrIllegalGeneration: // reset member ID and retry immediately |
| 294 | c.memberID = "" |
| 295 | return c.newSession(ctx, topics, handler, retries) |
| 296 | case ErrNotCoordinatorForConsumer: // retry after backoff with coordinator refresh |
| 297 | if retries <= 0 { |
| 298 | return nil, join.Err |
| 299 | } |
| 300 | |
| 301 | return c.retryNewSession(ctx, topics, handler, retries, true) |
| 302 | case ErrRebalanceInProgress: // retry after backoff |
| 303 | if retries <= 0 { |
| 304 | return nil, join.Err |
| 305 | } |
| 306 | |
| 307 | return c.retryNewSession(ctx, topics, handler, retries, false) |
| 308 | default: |
| 309 | return nil, join.Err |
| 310 | } |
| 311 | |
| 312 | // Prepare distribution plan if we joined as the leader |
| 313 | var plan BalanceStrategyPlan |
| 314 | if join.LeaderId == join.MemberId { |
| 315 | members, err := join.GetMembers() |
| 316 | if err != nil { |
| 317 | return nil, err |
| 318 | } |
| 319 | |
| 320 | plan, err = c.balance(members) |
| 321 | if err != nil { |
| 322 | return nil, err |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | // Sync consumer group |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 327 | groupRequest, err := c.syncGroupRequest(coordinator, plan, join.GenerationId) |
| 328 | if consumerGroupSyncTotal != nil { |
| 329 | consumerGroupSyncTotal.Inc(1) |
| 330 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 331 | if err != nil { |
| 332 | _ = coordinator.Close() |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 333 | if consumerGroupSyncFailed != nil { |
| 334 | consumerGroupSyncFailed.Inc(1) |
| 335 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 336 | return nil, err |
| 337 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 338 | if groupRequest.Err != ErrNoError { |
| 339 | if consumerGroupSyncFailed != nil { |
| 340 | consumerGroupSyncFailed.Inc(1) |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | switch groupRequest.Err { |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 345 | case ErrNoError: |
| 346 | case ErrUnknownMemberId, ErrIllegalGeneration: // reset member ID and retry immediately |
| 347 | c.memberID = "" |
| 348 | return c.newSession(ctx, topics, handler, retries) |
| 349 | case ErrNotCoordinatorForConsumer: // retry after backoff with coordinator refresh |
| 350 | if retries <= 0 { |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 351 | return nil, groupRequest.Err |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 352 | } |
| 353 | |
| 354 | return c.retryNewSession(ctx, topics, handler, retries, true) |
| 355 | case ErrRebalanceInProgress: // retry after backoff |
| 356 | if retries <= 0 { |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 357 | return nil, groupRequest.Err |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 358 | } |
| 359 | |
| 360 | return c.retryNewSession(ctx, topics, handler, retries, false) |
| 361 | default: |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 362 | return nil, groupRequest.Err |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 363 | } |
| 364 | |
| 365 | // Retrieve and sort claims |
| 366 | var claims map[string][]int32 |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 367 | if len(groupRequest.MemberAssignment) > 0 { |
| 368 | members, err := groupRequest.GetMemberAssignment() |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 369 | if err != nil { |
| 370 | return nil, err |
| 371 | } |
| 372 | claims = members.Topics |
| 373 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 374 | // in the case of stateful balance strategies, hold on to the returned |
| 375 | // assignment metadata, otherwise, reset the statically defined conusmer |
| 376 | // group metadata |
| 377 | if members.UserData != nil { |
| 378 | c.userData = members.UserData |
| 379 | } else { |
| 380 | c.userData = c.config.Consumer.Group.Member.UserData |
| 381 | } |
| 382 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 383 | for _, partitions := range claims { |
| 384 | sort.Sort(int32Slice(partitions)) |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | return newConsumerGroupSession(ctx, c, claims, join.MemberId, join.GenerationId, handler) |
| 389 | } |
| 390 | |
| 391 | func (c *consumerGroup) joinGroupRequest(coordinator *Broker, topics []string) (*JoinGroupResponse, error) { |
| 392 | req := &JoinGroupRequest{ |
| 393 | GroupId: c.groupID, |
| 394 | MemberId: c.memberID, |
| 395 | SessionTimeout: int32(c.config.Consumer.Group.Session.Timeout / time.Millisecond), |
| 396 | ProtocolType: "consumer", |
| 397 | } |
| 398 | if c.config.Version.IsAtLeast(V0_10_1_0) { |
| 399 | req.Version = 1 |
| 400 | req.RebalanceTimeout = int32(c.config.Consumer.Group.Rebalance.Timeout / time.Millisecond) |
| 401 | } |
| 402 | |
| 403 | meta := &ConsumerGroupMemberMetadata{ |
| 404 | Topics: topics, |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 405 | UserData: c.userData, |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 406 | } |
| 407 | strategy := c.config.Consumer.Group.Rebalance.Strategy |
| 408 | if err := req.AddGroupProtocolMetadata(strategy.Name(), meta); err != nil { |
| 409 | return nil, err |
| 410 | } |
| 411 | |
| 412 | return coordinator.JoinGroup(req) |
| 413 | } |
| 414 | |
| 415 | func (c *consumerGroup) syncGroupRequest(coordinator *Broker, plan BalanceStrategyPlan, generationID int32) (*SyncGroupResponse, error) { |
| 416 | req := &SyncGroupRequest{ |
| 417 | GroupId: c.groupID, |
| 418 | MemberId: c.memberID, |
| 419 | GenerationId: generationID, |
| 420 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 421 | strategy := c.config.Consumer.Group.Rebalance.Strategy |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 422 | for memberID, topics := range plan { |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 423 | assignment := &ConsumerGroupMemberAssignment{Topics: topics} |
| 424 | userDataBytes, err := strategy.AssignmentData(memberID, topics, generationID) |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 425 | if err != nil { |
| 426 | return nil, err |
| 427 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 428 | assignment.UserData = userDataBytes |
| 429 | if err := req.AddGroupAssignmentMember(memberID, assignment); err != nil { |
| 430 | return nil, err |
| 431 | } |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 432 | } |
| 433 | return coordinator.SyncGroup(req) |
| 434 | } |
| 435 | |
| 436 | func (c *consumerGroup) heartbeatRequest(coordinator *Broker, memberID string, generationID int32) (*HeartbeatResponse, error) { |
| 437 | req := &HeartbeatRequest{ |
| 438 | GroupId: c.groupID, |
| 439 | MemberId: memberID, |
| 440 | GenerationId: generationID, |
| 441 | } |
| 442 | |
| 443 | return coordinator.Heartbeat(req) |
| 444 | } |
| 445 | |
| 446 | func (c *consumerGroup) balance(members map[string]ConsumerGroupMemberMetadata) (BalanceStrategyPlan, error) { |
| 447 | topics := make(map[string][]int32) |
| 448 | for _, meta := range members { |
| 449 | for _, topic := range meta.Topics { |
| 450 | topics[topic] = nil |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | for topic := range topics { |
| 455 | partitions, err := c.client.Partitions(topic) |
| 456 | if err != nil { |
| 457 | return nil, err |
| 458 | } |
| 459 | topics[topic] = partitions |
| 460 | } |
| 461 | |
| 462 | strategy := c.config.Consumer.Group.Rebalance.Strategy |
| 463 | return strategy.Plan(members, topics) |
| 464 | } |
| 465 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 466 | // Leaves the cluster, called by Close. |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 467 | func (c *consumerGroup) leave() error { |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 468 | c.lock.Lock() |
| 469 | defer c.lock.Unlock() |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 470 | if c.memberID == "" { |
| 471 | return nil |
| 472 | } |
| 473 | |
| 474 | coordinator, err := c.client.Coordinator(c.groupID) |
| 475 | if err != nil { |
| 476 | return err |
| 477 | } |
| 478 | |
| 479 | resp, err := coordinator.LeaveGroup(&LeaveGroupRequest{ |
| 480 | GroupId: c.groupID, |
| 481 | MemberId: c.memberID, |
| 482 | }) |
| 483 | if err != nil { |
| 484 | _ = coordinator.Close() |
| 485 | return err |
| 486 | } |
| 487 | |
| 488 | // Unset memberID |
| 489 | c.memberID = "" |
| 490 | |
| 491 | // Check response |
| 492 | switch resp.Err { |
| 493 | case ErrRebalanceInProgress, ErrUnknownMemberId, ErrNoError: |
| 494 | return nil |
| 495 | default: |
| 496 | return resp.Err |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | func (c *consumerGroup) handleError(err error, topic string, partition int32) { |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 501 | if _, ok := err.(*ConsumerError); !ok && topic != "" && partition > -1 { |
| 502 | err = &ConsumerError{ |
| 503 | Topic: topic, |
| 504 | Partition: partition, |
| 505 | Err: err, |
| 506 | } |
| 507 | } |
| 508 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 509 | if !c.config.Consumer.Return.Errors { |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 510 | Logger.Println(err) |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 511 | return |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 512 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 513 | |
| 514 | select { |
| 515 | case <-c.closed: |
| 516 | // consumer is closed |
| 517 | return |
| 518 | default: |
| 519 | } |
| 520 | |
| 521 | select { |
| 522 | case c.errors <- err: |
| 523 | default: |
| 524 | // no error listener |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | func (c *consumerGroup) loopCheckPartitionNumbers(topics []string, session *consumerGroupSession) { |
| 529 | pause := time.NewTicker(c.config.Metadata.RefreshFrequency) |
| 530 | defer session.cancel() |
| 531 | defer pause.Stop() |
| 532 | var oldTopicToPartitionNum map[string]int |
| 533 | var err error |
| 534 | if oldTopicToPartitionNum, err = c.topicToPartitionNumbers(topics); err != nil { |
| 535 | return |
| 536 | } |
| 537 | for { |
| 538 | if newTopicToPartitionNum, err := c.topicToPartitionNumbers(topics); err != nil { |
| 539 | return |
| 540 | } else { |
| 541 | for topic, num := range oldTopicToPartitionNum { |
| 542 | if newTopicToPartitionNum[topic] != num { |
| 543 | return // trigger the end of the session on exit |
| 544 | } |
| 545 | } |
| 546 | } |
| 547 | select { |
| 548 | case <-pause.C: |
| 549 | case <-session.ctx.Done(): |
| 550 | Logger.Printf( |
| 551 | "consumergroup/%s loop check partition number coroutine will exit, topics %s\n", |
| 552 | c.groupID, topics) |
| 553 | // if session closed by other, should be exited |
| 554 | return |
| 555 | case <-c.closed: |
| 556 | return |
| 557 | } |
| 558 | } |
| 559 | } |
| 560 | |
| 561 | func (c *consumerGroup) topicToPartitionNumbers(topics []string) (map[string]int, error) { |
| 562 | topicToPartitionNum := make(map[string]int, len(topics)) |
| 563 | for _, topic := range topics { |
| 564 | if partitionNum, err := c.client.Partitions(topic); err != nil { |
| 565 | Logger.Printf( |
| 566 | "consumergroup/%s topic %s get partition number failed %v\n", |
| 567 | c.groupID, err) |
| 568 | return nil, err |
| 569 | } else { |
| 570 | topicToPartitionNum[topic] = len(partitionNum) |
| 571 | } |
| 572 | } |
| 573 | return topicToPartitionNum, nil |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 574 | } |
| 575 | |
| 576 | // -------------------------------------------------------------------- |
| 577 | |
| 578 | // ConsumerGroupSession represents a consumer group member session. |
| 579 | type ConsumerGroupSession interface { |
| 580 | // Claims returns information about the claimed partitions by topic. |
| 581 | Claims() map[string][]int32 |
| 582 | |
| 583 | // MemberID returns the cluster member ID. |
| 584 | MemberID() string |
| 585 | |
| 586 | // GenerationID returns the current generation ID. |
| 587 | GenerationID() int32 |
| 588 | |
| 589 | // MarkOffset marks the provided offset, alongside a metadata string |
| 590 | // that represents the state of the partition consumer at that point in time. The |
| 591 | // metadata string can be used by another consumer to restore that state, so it |
| 592 | // can resume consumption. |
| 593 | // |
| 594 | // To follow upstream conventions, you are expected to mark the offset of the |
| 595 | // next message to read, not the last message read. Thus, when calling `MarkOffset` |
| 596 | // you should typically add one to the offset of the last consumed message. |
| 597 | // |
| 598 | // Note: calling MarkOffset does not necessarily commit the offset to the backend |
| 599 | // store immediately for efficiency reasons, and it may never be committed if |
| 600 | // your application crashes. This means that you may end up processing the same |
| 601 | // message twice, and your processing should ideally be idempotent. |
| 602 | MarkOffset(topic string, partition int32, offset int64, metadata string) |
| 603 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 604 | // Commit the offset to the backend |
| 605 | // |
| 606 | // Note: calling Commit performs a blocking synchronous operation. |
| 607 | Commit() |
| 608 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 609 | // ResetOffset resets to the provided offset, alongside a metadata string that |
| 610 | // represents the state of the partition consumer at that point in time. Reset |
| 611 | // acts as a counterpart to MarkOffset, the difference being that it allows to |
| 612 | // reset an offset to an earlier or smaller value, where MarkOffset only |
| 613 | // allows incrementing the offset. cf MarkOffset for more details. |
| 614 | ResetOffset(topic string, partition int32, offset int64, metadata string) |
| 615 | |
| 616 | // MarkMessage marks a message as consumed. |
| 617 | MarkMessage(msg *ConsumerMessage, metadata string) |
| 618 | |
| 619 | // Context returns the session context. |
| 620 | Context() context.Context |
| 621 | } |
| 622 | |
| 623 | type consumerGroupSession struct { |
| 624 | parent *consumerGroup |
| 625 | memberID string |
| 626 | generationID int32 |
| 627 | handler ConsumerGroupHandler |
| 628 | |
| 629 | claims map[string][]int32 |
| 630 | offsets *offsetManager |
| 631 | ctx context.Context |
| 632 | cancel func() |
| 633 | |
| 634 | waitGroup sync.WaitGroup |
| 635 | releaseOnce sync.Once |
| 636 | hbDying, hbDead chan none |
| 637 | } |
| 638 | |
| 639 | func newConsumerGroupSession(ctx context.Context, parent *consumerGroup, claims map[string][]int32, memberID string, generationID int32, handler ConsumerGroupHandler) (*consumerGroupSession, error) { |
| 640 | // init offset manager |
| 641 | offsets, err := newOffsetManagerFromClient(parent.groupID, memberID, generationID, parent.client) |
| 642 | if err != nil { |
| 643 | return nil, err |
| 644 | } |
| 645 | |
| 646 | // init context |
| 647 | ctx, cancel := context.WithCancel(ctx) |
| 648 | |
| 649 | // init session |
| 650 | sess := &consumerGroupSession{ |
| 651 | parent: parent, |
| 652 | memberID: memberID, |
| 653 | generationID: generationID, |
| 654 | handler: handler, |
| 655 | offsets: offsets, |
| 656 | claims: claims, |
| 657 | ctx: ctx, |
| 658 | cancel: cancel, |
| 659 | hbDying: make(chan none), |
| 660 | hbDead: make(chan none), |
| 661 | } |
| 662 | |
| 663 | // start heartbeat loop |
| 664 | go sess.heartbeatLoop() |
| 665 | |
| 666 | // create a POM for each claim |
| 667 | for topic, partitions := range claims { |
| 668 | for _, partition := range partitions { |
| 669 | pom, err := offsets.ManagePartition(topic, partition) |
| 670 | if err != nil { |
| 671 | _ = sess.release(false) |
| 672 | return nil, err |
| 673 | } |
| 674 | |
| 675 | // handle POM errors |
| 676 | go func(topic string, partition int32) { |
| 677 | for err := range pom.Errors() { |
| 678 | sess.parent.handleError(err, topic, partition) |
| 679 | } |
| 680 | }(topic, partition) |
| 681 | } |
| 682 | } |
| 683 | |
| 684 | // perform setup |
| 685 | if err := handler.Setup(sess); err != nil { |
| 686 | _ = sess.release(true) |
| 687 | return nil, err |
| 688 | } |
| 689 | |
| 690 | // start consuming |
| 691 | for topic, partitions := range claims { |
| 692 | for _, partition := range partitions { |
| 693 | sess.waitGroup.Add(1) |
| 694 | |
| 695 | go func(topic string, partition int32) { |
| 696 | defer sess.waitGroup.Done() |
| 697 | |
| 698 | // cancel the as session as soon as the first |
| 699 | // goroutine exits |
| 700 | defer sess.cancel() |
| 701 | |
| 702 | // consume a single topic/partition, blocking |
| 703 | sess.consume(topic, partition) |
| 704 | }(topic, partition) |
| 705 | } |
| 706 | } |
| 707 | return sess, nil |
| 708 | } |
| 709 | |
| 710 | func (s *consumerGroupSession) Claims() map[string][]int32 { return s.claims } |
| 711 | func (s *consumerGroupSession) MemberID() string { return s.memberID } |
| 712 | func (s *consumerGroupSession) GenerationID() int32 { return s.generationID } |
| 713 | |
| 714 | func (s *consumerGroupSession) MarkOffset(topic string, partition int32, offset int64, metadata string) { |
| 715 | if pom := s.offsets.findPOM(topic, partition); pom != nil { |
| 716 | pom.MarkOffset(offset, metadata) |
| 717 | } |
| 718 | } |
| 719 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 720 | func (s *consumerGroupSession) Commit() { |
| 721 | s.offsets.Commit() |
| 722 | } |
| 723 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 724 | func (s *consumerGroupSession) ResetOffset(topic string, partition int32, offset int64, metadata string) { |
| 725 | if pom := s.offsets.findPOM(topic, partition); pom != nil { |
| 726 | pom.ResetOffset(offset, metadata) |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | func (s *consumerGroupSession) MarkMessage(msg *ConsumerMessage, metadata string) { |
| 731 | s.MarkOffset(msg.Topic, msg.Partition, msg.Offset+1, metadata) |
| 732 | } |
| 733 | |
| 734 | func (s *consumerGroupSession) Context() context.Context { |
| 735 | return s.ctx |
| 736 | } |
| 737 | |
| 738 | func (s *consumerGroupSession) consume(topic string, partition int32) { |
| 739 | // quick exit if rebalance is due |
| 740 | select { |
| 741 | case <-s.ctx.Done(): |
| 742 | return |
| 743 | case <-s.parent.closed: |
| 744 | return |
| 745 | default: |
| 746 | } |
| 747 | |
| 748 | // get next offset |
| 749 | offset := s.parent.config.Consumer.Offsets.Initial |
| 750 | if pom := s.offsets.findPOM(topic, partition); pom != nil { |
| 751 | offset, _ = pom.NextOffset() |
| 752 | } |
| 753 | |
| 754 | // create new claim |
| 755 | claim, err := newConsumerGroupClaim(s, topic, partition, offset) |
| 756 | if err != nil { |
| 757 | s.parent.handleError(err, topic, partition) |
| 758 | return |
| 759 | } |
| 760 | |
| 761 | // handle errors |
| 762 | go func() { |
| 763 | for err := range claim.Errors() { |
| 764 | s.parent.handleError(err, topic, partition) |
| 765 | } |
| 766 | }() |
| 767 | |
| 768 | // trigger close when session is done |
| 769 | go func() { |
| 770 | select { |
| 771 | case <-s.ctx.Done(): |
| 772 | case <-s.parent.closed: |
| 773 | } |
| 774 | claim.AsyncClose() |
| 775 | }() |
| 776 | |
| 777 | // start processing |
| 778 | if err := s.handler.ConsumeClaim(s, claim); err != nil { |
| 779 | s.parent.handleError(err, topic, partition) |
| 780 | } |
| 781 | |
| 782 | // ensure consumer is closed & drained |
| 783 | claim.AsyncClose() |
| 784 | for _, err := range claim.waitClosed() { |
| 785 | s.parent.handleError(err, topic, partition) |
| 786 | } |
| 787 | } |
| 788 | |
| 789 | func (s *consumerGroupSession) release(withCleanup bool) (err error) { |
| 790 | // signal release, stop heartbeat |
| 791 | s.cancel() |
| 792 | |
| 793 | // wait for consumers to exit |
| 794 | s.waitGroup.Wait() |
| 795 | |
| 796 | // perform release |
| 797 | s.releaseOnce.Do(func() { |
| 798 | if withCleanup { |
| 799 | if e := s.handler.Cleanup(s); e != nil { |
| 800 | s.parent.handleError(e, "", -1) |
| 801 | err = e |
| 802 | } |
| 803 | } |
| 804 | |
| 805 | if e := s.offsets.Close(); e != nil { |
| 806 | err = e |
| 807 | } |
| 808 | |
| 809 | close(s.hbDying) |
| 810 | <-s.hbDead |
| 811 | }) |
| 812 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 813 | Logger.Printf( |
| 814 | "consumergroup/session/%s/%d released\n", |
| 815 | s.MemberID(), s.GenerationID()) |
| 816 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 817 | return |
| 818 | } |
| 819 | |
| 820 | func (s *consumerGroupSession) heartbeatLoop() { |
| 821 | defer close(s.hbDead) |
| 822 | defer s.cancel() // trigger the end of the session on exit |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 823 | defer func() { |
| 824 | Logger.Printf( |
| 825 | "consumergroup/session/%s/%d heartbeat loop stopped\n", |
| 826 | s.MemberID(), s.GenerationID()) |
| 827 | }() |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 828 | |
| 829 | pause := time.NewTicker(s.parent.config.Consumer.Group.Heartbeat.Interval) |
| 830 | defer pause.Stop() |
| 831 | |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 832 | retryBackoff := time.NewTimer(s.parent.config.Metadata.Retry.Backoff) |
| 833 | defer retryBackoff.Stop() |
| 834 | |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 835 | retries := s.parent.config.Metadata.Retry.Max |
| 836 | for { |
| 837 | coordinator, err := s.parent.client.Coordinator(s.parent.groupID) |
| 838 | if err != nil { |
| 839 | if retries <= 0 { |
| 840 | s.parent.handleError(err, "", -1) |
| 841 | return |
| 842 | } |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 843 | retryBackoff.Reset(s.parent.config.Metadata.Retry.Backoff) |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 844 | select { |
| 845 | case <-s.hbDying: |
| 846 | return |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 847 | case <-retryBackoff.C: |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 848 | retries-- |
| 849 | } |
| 850 | continue |
| 851 | } |
| 852 | |
| 853 | resp, err := s.parent.heartbeatRequest(coordinator, s.memberID, s.generationID) |
| 854 | if err != nil { |
| 855 | _ = coordinator.Close() |
| 856 | |
| 857 | if retries <= 0 { |
| 858 | s.parent.handleError(err, "", -1) |
| 859 | return |
| 860 | } |
| 861 | |
| 862 | retries-- |
| 863 | continue |
| 864 | } |
| 865 | |
| 866 | switch resp.Err { |
| 867 | case ErrNoError: |
| 868 | retries = s.parent.config.Metadata.Retry.Max |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 869 | case ErrRebalanceInProgress: |
| 870 | retries = s.parent.config.Metadata.Retry.Max |
| 871 | s.cancel() |
| 872 | case ErrUnknownMemberId, ErrIllegalGeneration: |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 873 | return |
| 874 | default: |
kesavand | c71914f | 2022-03-25 11:19:03 +0530 | [diff] [blame^] | 875 | s.parent.handleError(resp.Err, "", -1) |
kesavand | 2cde658 | 2020-06-22 04:56:23 -0400 | [diff] [blame] | 876 | return |
| 877 | } |
| 878 | |
| 879 | select { |
| 880 | case <-pause.C: |
| 881 | case <-s.hbDying: |
| 882 | return |
| 883 | } |
| 884 | } |
| 885 | } |
| 886 | |
| 887 | // -------------------------------------------------------------------- |
| 888 | |
| 889 | // ConsumerGroupHandler instances are used to handle individual topic/partition claims. |
| 890 | // It also provides hooks for your consumer group session life-cycle and allow you to |
| 891 | // trigger logic before or after the consume loop(s). |
| 892 | // |
| 893 | // PLEASE NOTE that handlers are likely be called from several goroutines concurrently, |
| 894 | // ensure that all state is safely protected against race conditions. |
| 895 | type ConsumerGroupHandler interface { |
| 896 | // Setup is run at the beginning of a new session, before ConsumeClaim. |
| 897 | Setup(ConsumerGroupSession) error |
| 898 | |
| 899 | // Cleanup is run at the end of a session, once all ConsumeClaim goroutines have exited |
| 900 | // but before the offsets are committed for the very last time. |
| 901 | Cleanup(ConsumerGroupSession) error |
| 902 | |
| 903 | // ConsumeClaim must start a consumer loop of ConsumerGroupClaim's Messages(). |
| 904 | // Once the Messages() channel is closed, the Handler must finish its processing |
| 905 | // loop and exit. |
| 906 | ConsumeClaim(ConsumerGroupSession, ConsumerGroupClaim) error |
| 907 | } |
| 908 | |
| 909 | // ConsumerGroupClaim processes Kafka messages from a given topic and partition within a consumer group. |
| 910 | type ConsumerGroupClaim interface { |
| 911 | // Topic returns the consumed topic name. |
| 912 | Topic() string |
| 913 | |
| 914 | // Partition returns the consumed partition. |
| 915 | Partition() int32 |
| 916 | |
| 917 | // InitialOffset returns the initial offset that was used as a starting point for this claim. |
| 918 | InitialOffset() int64 |
| 919 | |
| 920 | // HighWaterMarkOffset returns the high water mark offset of the partition, |
| 921 | // i.e. the offset that will be used for the next message that will be produced. |
| 922 | // You can use this to determine how far behind the processing is. |
| 923 | HighWaterMarkOffset() int64 |
| 924 | |
| 925 | // Messages returns the read channel for the messages that are returned by |
| 926 | // the broker. The messages channel will be closed when a new rebalance cycle |
| 927 | // is due. You must finish processing and mark offsets within |
| 928 | // Config.Consumer.Group.Session.Timeout before the topic/partition is eventually |
| 929 | // re-assigned to another group member. |
| 930 | Messages() <-chan *ConsumerMessage |
| 931 | } |
| 932 | |
| 933 | type consumerGroupClaim struct { |
| 934 | topic string |
| 935 | partition int32 |
| 936 | offset int64 |
| 937 | PartitionConsumer |
| 938 | } |
| 939 | |
| 940 | func newConsumerGroupClaim(sess *consumerGroupSession, topic string, partition int32, offset int64) (*consumerGroupClaim, error) { |
| 941 | pcm, err := sess.parent.consumer.ConsumePartition(topic, partition, offset) |
| 942 | if err == ErrOffsetOutOfRange { |
| 943 | offset = sess.parent.config.Consumer.Offsets.Initial |
| 944 | pcm, err = sess.parent.consumer.ConsumePartition(topic, partition, offset) |
| 945 | } |
| 946 | if err != nil { |
| 947 | return nil, err |
| 948 | } |
| 949 | |
| 950 | go func() { |
| 951 | for err := range pcm.Errors() { |
| 952 | sess.parent.handleError(err, topic, partition) |
| 953 | } |
| 954 | }() |
| 955 | |
| 956 | return &consumerGroupClaim{ |
| 957 | topic: topic, |
| 958 | partition: partition, |
| 959 | offset: offset, |
| 960 | PartitionConsumer: pcm, |
| 961 | }, nil |
| 962 | } |
| 963 | |
| 964 | func (c *consumerGroupClaim) Topic() string { return c.topic } |
| 965 | func (c *consumerGroupClaim) Partition() int32 { return c.partition } |
| 966 | func (c *consumerGroupClaim) InitialOffset() int64 { return c.offset } |
| 967 | |
| 968 | // Drains messages and errors, ensures the claim is fully closed. |
| 969 | func (c *consumerGroupClaim) waitClosed() (errs ConsumerErrors) { |
| 970 | go func() { |
| 971 | for range c.Messages() { |
| 972 | } |
| 973 | }() |
| 974 | |
| 975 | for err := range c.Errors() { |
| 976 | errs = append(errs, err) |
| 977 | } |
| 978 | return |
| 979 | } |