Joey Armstrong | 5f51f2e | 2023-01-17 17:06:26 -0500 | [diff] [blame^] | 1 | package redis |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "crypto/tls" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "net" |
| 9 | "strconv" |
| 10 | "sync" |
| 11 | "sync/atomic" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/cespare/xxhash/v2" |
| 15 | "github.com/dgryski/go-rendezvous" |
| 16 | "github.com/go-redis/redis/v8/internal" |
| 17 | "github.com/go-redis/redis/v8/internal/hashtag" |
| 18 | "github.com/go-redis/redis/v8/internal/pool" |
| 19 | "github.com/go-redis/redis/v8/internal/rand" |
| 20 | ) |
| 21 | |
| 22 | var errRingShardsDown = errors.New("redis: all ring shards are down") |
| 23 | |
| 24 | //------------------------------------------------------------------------------ |
| 25 | |
| 26 | type ConsistentHash interface { |
| 27 | Get(string) string |
| 28 | } |
| 29 | |
| 30 | type rendezvousWrapper struct { |
| 31 | *rendezvous.Rendezvous |
| 32 | } |
| 33 | |
| 34 | func (w rendezvousWrapper) Get(key string) string { |
| 35 | return w.Lookup(key) |
| 36 | } |
| 37 | |
| 38 | func newRendezvous(shards []string) ConsistentHash { |
| 39 | return rendezvousWrapper{rendezvous.New(shards, xxhash.Sum64String)} |
| 40 | } |
| 41 | |
| 42 | //------------------------------------------------------------------------------ |
| 43 | |
| 44 | // RingOptions are used to configure a ring client and should be |
| 45 | // passed to NewRing. |
| 46 | type RingOptions struct { |
| 47 | // Map of name => host:port addresses of ring shards. |
| 48 | Addrs map[string]string |
| 49 | |
| 50 | // NewClient creates a shard client with provided name and options. |
| 51 | NewClient func(name string, opt *Options) *Client |
| 52 | |
| 53 | // Frequency of PING commands sent to check shards availability. |
| 54 | // Shard is considered down after 3 subsequent failed checks. |
| 55 | HeartbeatFrequency time.Duration |
| 56 | |
| 57 | // NewConsistentHash returns a consistent hash that is used |
| 58 | // to distribute keys across the shards. |
| 59 | // |
| 60 | // See https://medium.com/@dgryski/consistent-hashing-algorithmic-tradeoffs-ef6b8e2fcae8 |
| 61 | // for consistent hashing algorithmic tradeoffs. |
| 62 | NewConsistentHash func(shards []string) ConsistentHash |
| 63 | |
| 64 | // Following options are copied from Options struct. |
| 65 | |
| 66 | Dialer func(ctx context.Context, network, addr string) (net.Conn, error) |
| 67 | OnConnect func(ctx context.Context, cn *Conn) error |
| 68 | |
| 69 | Username string |
| 70 | Password string |
| 71 | DB int |
| 72 | |
| 73 | MaxRetries int |
| 74 | MinRetryBackoff time.Duration |
| 75 | MaxRetryBackoff time.Duration |
| 76 | |
| 77 | DialTimeout time.Duration |
| 78 | ReadTimeout time.Duration |
| 79 | WriteTimeout time.Duration |
| 80 | |
| 81 | PoolSize int |
| 82 | MinIdleConns int |
| 83 | MaxConnAge time.Duration |
| 84 | PoolTimeout time.Duration |
| 85 | IdleTimeout time.Duration |
| 86 | IdleCheckFrequency time.Duration |
| 87 | |
| 88 | TLSConfig *tls.Config |
| 89 | Limiter Limiter |
| 90 | } |
| 91 | |
| 92 | func (opt *RingOptions) init() { |
| 93 | if opt.NewClient == nil { |
| 94 | opt.NewClient = func(name string, opt *Options) *Client { |
| 95 | return NewClient(opt) |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | if opt.HeartbeatFrequency == 0 { |
| 100 | opt.HeartbeatFrequency = 500 * time.Millisecond |
| 101 | } |
| 102 | |
| 103 | if opt.NewConsistentHash == nil { |
| 104 | opt.NewConsistentHash = newRendezvous |
| 105 | } |
| 106 | |
| 107 | if opt.MaxRetries == -1 { |
| 108 | opt.MaxRetries = 0 |
| 109 | } else if opt.MaxRetries == 0 { |
| 110 | opt.MaxRetries = 3 |
| 111 | } |
| 112 | switch opt.MinRetryBackoff { |
| 113 | case -1: |
| 114 | opt.MinRetryBackoff = 0 |
| 115 | case 0: |
| 116 | opt.MinRetryBackoff = 8 * time.Millisecond |
| 117 | } |
| 118 | switch opt.MaxRetryBackoff { |
| 119 | case -1: |
| 120 | opt.MaxRetryBackoff = 0 |
| 121 | case 0: |
| 122 | opt.MaxRetryBackoff = 512 * time.Millisecond |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | func (opt *RingOptions) clientOptions() *Options { |
| 127 | return &Options{ |
| 128 | Dialer: opt.Dialer, |
| 129 | OnConnect: opt.OnConnect, |
| 130 | |
| 131 | Username: opt.Username, |
| 132 | Password: opt.Password, |
| 133 | DB: opt.DB, |
| 134 | |
| 135 | MaxRetries: -1, |
| 136 | |
| 137 | DialTimeout: opt.DialTimeout, |
| 138 | ReadTimeout: opt.ReadTimeout, |
| 139 | WriteTimeout: opt.WriteTimeout, |
| 140 | |
| 141 | PoolSize: opt.PoolSize, |
| 142 | MinIdleConns: opt.MinIdleConns, |
| 143 | MaxConnAge: opt.MaxConnAge, |
| 144 | PoolTimeout: opt.PoolTimeout, |
| 145 | IdleTimeout: opt.IdleTimeout, |
| 146 | IdleCheckFrequency: opt.IdleCheckFrequency, |
| 147 | |
| 148 | TLSConfig: opt.TLSConfig, |
| 149 | Limiter: opt.Limiter, |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | //------------------------------------------------------------------------------ |
| 154 | |
| 155 | type ringShard struct { |
| 156 | Client *Client |
| 157 | down int32 |
| 158 | } |
| 159 | |
| 160 | func newRingShard(opt *RingOptions, name, addr string) *ringShard { |
| 161 | clopt := opt.clientOptions() |
| 162 | clopt.Addr = addr |
| 163 | |
| 164 | return &ringShard{ |
| 165 | Client: opt.NewClient(name, clopt), |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | func (shard *ringShard) String() string { |
| 170 | var state string |
| 171 | if shard.IsUp() { |
| 172 | state = "up" |
| 173 | } else { |
| 174 | state = "down" |
| 175 | } |
| 176 | return fmt.Sprintf("%s is %s", shard.Client, state) |
| 177 | } |
| 178 | |
| 179 | func (shard *ringShard) IsDown() bool { |
| 180 | const threshold = 3 |
| 181 | return atomic.LoadInt32(&shard.down) >= threshold |
| 182 | } |
| 183 | |
| 184 | func (shard *ringShard) IsUp() bool { |
| 185 | return !shard.IsDown() |
| 186 | } |
| 187 | |
| 188 | // Vote votes to set shard state and returns true if state was changed. |
| 189 | func (shard *ringShard) Vote(up bool) bool { |
| 190 | if up { |
| 191 | changed := shard.IsDown() |
| 192 | atomic.StoreInt32(&shard.down, 0) |
| 193 | return changed |
| 194 | } |
| 195 | |
| 196 | if shard.IsDown() { |
| 197 | return false |
| 198 | } |
| 199 | |
| 200 | atomic.AddInt32(&shard.down, 1) |
| 201 | return shard.IsDown() |
| 202 | } |
| 203 | |
| 204 | //------------------------------------------------------------------------------ |
| 205 | |
| 206 | type ringShards struct { |
| 207 | opt *RingOptions |
| 208 | |
| 209 | mu sync.RWMutex |
| 210 | hash ConsistentHash |
| 211 | shards map[string]*ringShard // read only |
| 212 | list []*ringShard // read only |
| 213 | numShard int |
| 214 | closed bool |
| 215 | } |
| 216 | |
| 217 | func newRingShards(opt *RingOptions) *ringShards { |
| 218 | shards := make(map[string]*ringShard, len(opt.Addrs)) |
| 219 | list := make([]*ringShard, 0, len(shards)) |
| 220 | |
| 221 | for name, addr := range opt.Addrs { |
| 222 | shard := newRingShard(opt, name, addr) |
| 223 | shards[name] = shard |
| 224 | |
| 225 | list = append(list, shard) |
| 226 | } |
| 227 | |
| 228 | c := &ringShards{ |
| 229 | opt: opt, |
| 230 | |
| 231 | shards: shards, |
| 232 | list: list, |
| 233 | } |
| 234 | c.rebalance() |
| 235 | |
| 236 | return c |
| 237 | } |
| 238 | |
| 239 | func (c *ringShards) List() []*ringShard { |
| 240 | var list []*ringShard |
| 241 | |
| 242 | c.mu.RLock() |
| 243 | if !c.closed { |
| 244 | list = c.list |
| 245 | } |
| 246 | c.mu.RUnlock() |
| 247 | |
| 248 | return list |
| 249 | } |
| 250 | |
| 251 | func (c *ringShards) Hash(key string) string { |
| 252 | key = hashtag.Key(key) |
| 253 | |
| 254 | var hash string |
| 255 | |
| 256 | c.mu.RLock() |
| 257 | if c.numShard > 0 { |
| 258 | hash = c.hash.Get(key) |
| 259 | } |
| 260 | c.mu.RUnlock() |
| 261 | |
| 262 | return hash |
| 263 | } |
| 264 | |
| 265 | func (c *ringShards) GetByKey(key string) (*ringShard, error) { |
| 266 | key = hashtag.Key(key) |
| 267 | |
| 268 | c.mu.RLock() |
| 269 | |
| 270 | if c.closed { |
| 271 | c.mu.RUnlock() |
| 272 | return nil, pool.ErrClosed |
| 273 | } |
| 274 | |
| 275 | if c.numShard == 0 { |
| 276 | c.mu.RUnlock() |
| 277 | return nil, errRingShardsDown |
| 278 | } |
| 279 | |
| 280 | hash := c.hash.Get(key) |
| 281 | if hash == "" { |
| 282 | c.mu.RUnlock() |
| 283 | return nil, errRingShardsDown |
| 284 | } |
| 285 | |
| 286 | shard := c.shards[hash] |
| 287 | c.mu.RUnlock() |
| 288 | |
| 289 | return shard, nil |
| 290 | } |
| 291 | |
| 292 | func (c *ringShards) GetByName(shardName string) (*ringShard, error) { |
| 293 | if shardName == "" { |
| 294 | return c.Random() |
| 295 | } |
| 296 | |
| 297 | c.mu.RLock() |
| 298 | shard := c.shards[shardName] |
| 299 | c.mu.RUnlock() |
| 300 | return shard, nil |
| 301 | } |
| 302 | |
| 303 | func (c *ringShards) Random() (*ringShard, error) { |
| 304 | return c.GetByKey(strconv.Itoa(rand.Int())) |
| 305 | } |
| 306 | |
| 307 | // heartbeat monitors state of each shard in the ring. |
| 308 | func (c *ringShards) Heartbeat(frequency time.Duration) { |
| 309 | ticker := time.NewTicker(frequency) |
| 310 | defer ticker.Stop() |
| 311 | |
| 312 | ctx := context.Background() |
| 313 | for range ticker.C { |
| 314 | var rebalance bool |
| 315 | |
| 316 | for _, shard := range c.List() { |
| 317 | err := shard.Client.Ping(ctx).Err() |
| 318 | isUp := err == nil || err == pool.ErrPoolTimeout |
| 319 | if shard.Vote(isUp) { |
| 320 | internal.Logger.Printf(context.Background(), "ring shard state changed: %s", shard) |
| 321 | rebalance = true |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | if rebalance { |
| 326 | c.rebalance() |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | // rebalance removes dead shards from the Ring. |
| 332 | func (c *ringShards) rebalance() { |
| 333 | c.mu.RLock() |
| 334 | shards := c.shards |
| 335 | c.mu.RUnlock() |
| 336 | |
| 337 | liveShards := make([]string, 0, len(shards)) |
| 338 | |
| 339 | for name, shard := range shards { |
| 340 | if shard.IsUp() { |
| 341 | liveShards = append(liveShards, name) |
| 342 | } |
| 343 | } |
| 344 | |
| 345 | hash := c.opt.NewConsistentHash(liveShards) |
| 346 | |
| 347 | c.mu.Lock() |
| 348 | c.hash = hash |
| 349 | c.numShard = len(liveShards) |
| 350 | c.mu.Unlock() |
| 351 | } |
| 352 | |
| 353 | func (c *ringShards) Len() int { |
| 354 | c.mu.RLock() |
| 355 | l := c.numShard |
| 356 | c.mu.RUnlock() |
| 357 | return l |
| 358 | } |
| 359 | |
| 360 | func (c *ringShards) Close() error { |
| 361 | c.mu.Lock() |
| 362 | defer c.mu.Unlock() |
| 363 | |
| 364 | if c.closed { |
| 365 | return nil |
| 366 | } |
| 367 | c.closed = true |
| 368 | |
| 369 | var firstErr error |
| 370 | for _, shard := range c.shards { |
| 371 | if err := shard.Client.Close(); err != nil && firstErr == nil { |
| 372 | firstErr = err |
| 373 | } |
| 374 | } |
| 375 | c.hash = nil |
| 376 | c.shards = nil |
| 377 | c.list = nil |
| 378 | |
| 379 | return firstErr |
| 380 | } |
| 381 | |
| 382 | //------------------------------------------------------------------------------ |
| 383 | |
| 384 | type ring struct { |
| 385 | opt *RingOptions |
| 386 | shards *ringShards |
| 387 | cmdsInfoCache *cmdsInfoCache //nolint:structcheck |
| 388 | } |
| 389 | |
| 390 | // Ring is a Redis client that uses consistent hashing to distribute |
| 391 | // keys across multiple Redis servers (shards). It's safe for |
| 392 | // concurrent use by multiple goroutines. |
| 393 | // |
| 394 | // Ring monitors the state of each shard and removes dead shards from |
| 395 | // the ring. When a shard comes online it is added back to the ring. This |
| 396 | // gives you maximum availability and partition tolerance, but no |
| 397 | // consistency between different shards or even clients. Each client |
| 398 | // uses shards that are available to the client and does not do any |
| 399 | // coordination when shard state is changed. |
| 400 | // |
| 401 | // Ring should be used when you need multiple Redis servers for caching |
| 402 | // and can tolerate losing data when one of the servers dies. |
| 403 | // Otherwise you should use Redis Cluster. |
| 404 | type Ring struct { |
| 405 | *ring |
| 406 | cmdable |
| 407 | hooks |
| 408 | ctx context.Context |
| 409 | } |
| 410 | |
| 411 | func NewRing(opt *RingOptions) *Ring { |
| 412 | opt.init() |
| 413 | |
| 414 | ring := Ring{ |
| 415 | ring: &ring{ |
| 416 | opt: opt, |
| 417 | shards: newRingShards(opt), |
| 418 | }, |
| 419 | ctx: context.Background(), |
| 420 | } |
| 421 | |
| 422 | ring.cmdsInfoCache = newCmdsInfoCache(ring.cmdsInfo) |
| 423 | ring.cmdable = ring.Process |
| 424 | |
| 425 | go ring.shards.Heartbeat(opt.HeartbeatFrequency) |
| 426 | |
| 427 | return &ring |
| 428 | } |
| 429 | |
| 430 | func (c *Ring) Context() context.Context { |
| 431 | return c.ctx |
| 432 | } |
| 433 | |
| 434 | func (c *Ring) WithContext(ctx context.Context) *Ring { |
| 435 | if ctx == nil { |
| 436 | panic("nil context") |
| 437 | } |
| 438 | clone := *c |
| 439 | clone.cmdable = clone.Process |
| 440 | clone.hooks.lock() |
| 441 | clone.ctx = ctx |
| 442 | return &clone |
| 443 | } |
| 444 | |
| 445 | // Do creates a Cmd from the args and processes the cmd. |
| 446 | func (c *Ring) Do(ctx context.Context, args ...interface{}) *Cmd { |
| 447 | cmd := NewCmd(ctx, args...) |
| 448 | _ = c.Process(ctx, cmd) |
| 449 | return cmd |
| 450 | } |
| 451 | |
| 452 | func (c *Ring) Process(ctx context.Context, cmd Cmder) error { |
| 453 | return c.hooks.process(ctx, cmd, c.process) |
| 454 | } |
| 455 | |
| 456 | // Options returns read-only Options that were used to create the client. |
| 457 | func (c *Ring) Options() *RingOptions { |
| 458 | return c.opt |
| 459 | } |
| 460 | |
| 461 | func (c *Ring) retryBackoff(attempt int) time.Duration { |
| 462 | return internal.RetryBackoff(attempt, c.opt.MinRetryBackoff, c.opt.MaxRetryBackoff) |
| 463 | } |
| 464 | |
| 465 | // PoolStats returns accumulated connection pool stats. |
| 466 | func (c *Ring) PoolStats() *PoolStats { |
| 467 | shards := c.shards.List() |
| 468 | var acc PoolStats |
| 469 | for _, shard := range shards { |
| 470 | s := shard.Client.connPool.Stats() |
| 471 | acc.Hits += s.Hits |
| 472 | acc.Misses += s.Misses |
| 473 | acc.Timeouts += s.Timeouts |
| 474 | acc.TotalConns += s.TotalConns |
| 475 | acc.IdleConns += s.IdleConns |
| 476 | } |
| 477 | return &acc |
| 478 | } |
| 479 | |
| 480 | // Len returns the current number of shards in the ring. |
| 481 | func (c *Ring) Len() int { |
| 482 | return c.shards.Len() |
| 483 | } |
| 484 | |
| 485 | // Subscribe subscribes the client to the specified channels. |
| 486 | func (c *Ring) Subscribe(ctx context.Context, channels ...string) *PubSub { |
| 487 | if len(channels) == 0 { |
| 488 | panic("at least one channel is required") |
| 489 | } |
| 490 | |
| 491 | shard, err := c.shards.GetByKey(channels[0]) |
| 492 | if err != nil { |
| 493 | // TODO: return PubSub with sticky error |
| 494 | panic(err) |
| 495 | } |
| 496 | return shard.Client.Subscribe(ctx, channels...) |
| 497 | } |
| 498 | |
| 499 | // PSubscribe subscribes the client to the given patterns. |
| 500 | func (c *Ring) PSubscribe(ctx context.Context, channels ...string) *PubSub { |
| 501 | if len(channels) == 0 { |
| 502 | panic("at least one channel is required") |
| 503 | } |
| 504 | |
| 505 | shard, err := c.shards.GetByKey(channels[0]) |
| 506 | if err != nil { |
| 507 | // TODO: return PubSub with sticky error |
| 508 | panic(err) |
| 509 | } |
| 510 | return shard.Client.PSubscribe(ctx, channels...) |
| 511 | } |
| 512 | |
| 513 | // ForEachShard concurrently calls the fn on each live shard in the ring. |
| 514 | // It returns the first error if any. |
| 515 | func (c *Ring) ForEachShard( |
| 516 | ctx context.Context, |
| 517 | fn func(ctx context.Context, client *Client) error, |
| 518 | ) error { |
| 519 | shards := c.shards.List() |
| 520 | var wg sync.WaitGroup |
| 521 | errCh := make(chan error, 1) |
| 522 | for _, shard := range shards { |
| 523 | if shard.IsDown() { |
| 524 | continue |
| 525 | } |
| 526 | |
| 527 | wg.Add(1) |
| 528 | go func(shard *ringShard) { |
| 529 | defer wg.Done() |
| 530 | err := fn(ctx, shard.Client) |
| 531 | if err != nil { |
| 532 | select { |
| 533 | case errCh <- err: |
| 534 | default: |
| 535 | } |
| 536 | } |
| 537 | }(shard) |
| 538 | } |
| 539 | wg.Wait() |
| 540 | |
| 541 | select { |
| 542 | case err := <-errCh: |
| 543 | return err |
| 544 | default: |
| 545 | return nil |
| 546 | } |
| 547 | } |
| 548 | |
| 549 | func (c *Ring) cmdsInfo(ctx context.Context) (map[string]*CommandInfo, error) { |
| 550 | shards := c.shards.List() |
| 551 | var firstErr error |
| 552 | for _, shard := range shards { |
| 553 | cmdsInfo, err := shard.Client.Command(ctx).Result() |
| 554 | if err == nil { |
| 555 | return cmdsInfo, nil |
| 556 | } |
| 557 | if firstErr == nil { |
| 558 | firstErr = err |
| 559 | } |
| 560 | } |
| 561 | if firstErr == nil { |
| 562 | return nil, errRingShardsDown |
| 563 | } |
| 564 | return nil, firstErr |
| 565 | } |
| 566 | |
| 567 | func (c *Ring) cmdInfo(ctx context.Context, name string) *CommandInfo { |
| 568 | cmdsInfo, err := c.cmdsInfoCache.Get(ctx) |
| 569 | if err != nil { |
| 570 | return nil |
| 571 | } |
| 572 | info := cmdsInfo[name] |
| 573 | if info == nil { |
| 574 | internal.Logger.Printf(c.Context(), "info for cmd=%s not found", name) |
| 575 | } |
| 576 | return info |
| 577 | } |
| 578 | |
| 579 | func (c *Ring) cmdShard(ctx context.Context, cmd Cmder) (*ringShard, error) { |
| 580 | cmdInfo := c.cmdInfo(ctx, cmd.Name()) |
| 581 | pos := cmdFirstKeyPos(cmd, cmdInfo) |
| 582 | if pos == 0 { |
| 583 | return c.shards.Random() |
| 584 | } |
| 585 | firstKey := cmd.stringArg(pos) |
| 586 | return c.shards.GetByKey(firstKey) |
| 587 | } |
| 588 | |
| 589 | func (c *Ring) process(ctx context.Context, cmd Cmder) error { |
| 590 | var lastErr error |
| 591 | for attempt := 0; attempt <= c.opt.MaxRetries; attempt++ { |
| 592 | if attempt > 0 { |
| 593 | if err := internal.Sleep(ctx, c.retryBackoff(attempt)); err != nil { |
| 594 | return err |
| 595 | } |
| 596 | } |
| 597 | |
| 598 | shard, err := c.cmdShard(ctx, cmd) |
| 599 | if err != nil { |
| 600 | return err |
| 601 | } |
| 602 | |
| 603 | lastErr = shard.Client.Process(ctx, cmd) |
| 604 | if lastErr == nil || !shouldRetry(lastErr, cmd.readTimeout() == nil) { |
| 605 | return lastErr |
| 606 | } |
| 607 | } |
| 608 | return lastErr |
| 609 | } |
| 610 | |
| 611 | func (c *Ring) Pipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) { |
| 612 | return c.Pipeline().Pipelined(ctx, fn) |
| 613 | } |
| 614 | |
| 615 | func (c *Ring) Pipeline() Pipeliner { |
| 616 | pipe := Pipeline{ |
| 617 | ctx: c.ctx, |
| 618 | exec: c.processPipeline, |
| 619 | } |
| 620 | pipe.init() |
| 621 | return &pipe |
| 622 | } |
| 623 | |
| 624 | func (c *Ring) processPipeline(ctx context.Context, cmds []Cmder) error { |
| 625 | return c.hooks.processPipeline(ctx, cmds, func(ctx context.Context, cmds []Cmder) error { |
| 626 | return c.generalProcessPipeline(ctx, cmds, false) |
| 627 | }) |
| 628 | } |
| 629 | |
| 630 | func (c *Ring) TxPipelined(ctx context.Context, fn func(Pipeliner) error) ([]Cmder, error) { |
| 631 | return c.TxPipeline().Pipelined(ctx, fn) |
| 632 | } |
| 633 | |
| 634 | func (c *Ring) TxPipeline() Pipeliner { |
| 635 | pipe := Pipeline{ |
| 636 | ctx: c.ctx, |
| 637 | exec: c.processTxPipeline, |
| 638 | } |
| 639 | pipe.init() |
| 640 | return &pipe |
| 641 | } |
| 642 | |
| 643 | func (c *Ring) processTxPipeline(ctx context.Context, cmds []Cmder) error { |
| 644 | return c.hooks.processPipeline(ctx, cmds, func(ctx context.Context, cmds []Cmder) error { |
| 645 | return c.generalProcessPipeline(ctx, cmds, true) |
| 646 | }) |
| 647 | } |
| 648 | |
| 649 | func (c *Ring) generalProcessPipeline( |
| 650 | ctx context.Context, cmds []Cmder, tx bool, |
| 651 | ) error { |
| 652 | cmdsMap := make(map[string][]Cmder) |
| 653 | for _, cmd := range cmds { |
| 654 | cmdInfo := c.cmdInfo(ctx, cmd.Name()) |
| 655 | hash := cmd.stringArg(cmdFirstKeyPos(cmd, cmdInfo)) |
| 656 | if hash != "" { |
| 657 | hash = c.shards.Hash(hash) |
| 658 | } |
| 659 | cmdsMap[hash] = append(cmdsMap[hash], cmd) |
| 660 | } |
| 661 | |
| 662 | var wg sync.WaitGroup |
| 663 | for hash, cmds := range cmdsMap { |
| 664 | wg.Add(1) |
| 665 | go func(hash string, cmds []Cmder) { |
| 666 | defer wg.Done() |
| 667 | |
| 668 | _ = c.processShardPipeline(ctx, hash, cmds, tx) |
| 669 | }(hash, cmds) |
| 670 | } |
| 671 | |
| 672 | wg.Wait() |
| 673 | return cmdsFirstErr(cmds) |
| 674 | } |
| 675 | |
| 676 | func (c *Ring) processShardPipeline( |
| 677 | ctx context.Context, hash string, cmds []Cmder, tx bool, |
| 678 | ) error { |
| 679 | // TODO: retry? |
| 680 | shard, err := c.shards.GetByName(hash) |
| 681 | if err != nil { |
| 682 | setCmdsErr(cmds, err) |
| 683 | return err |
| 684 | } |
| 685 | |
| 686 | if tx { |
| 687 | return shard.Client.processTxPipeline(ctx, cmds) |
| 688 | } |
| 689 | return shard.Client.processPipeline(ctx, cmds) |
| 690 | } |
| 691 | |
| 692 | func (c *Ring) Watch(ctx context.Context, fn func(*Tx) error, keys ...string) error { |
| 693 | if len(keys) == 0 { |
| 694 | return fmt.Errorf("redis: Watch requires at least one key") |
| 695 | } |
| 696 | |
| 697 | var shards []*ringShard |
| 698 | for _, key := range keys { |
| 699 | if key != "" { |
| 700 | shard, err := c.shards.GetByKey(hashtag.Key(key)) |
| 701 | if err != nil { |
| 702 | return err |
| 703 | } |
| 704 | |
| 705 | shards = append(shards, shard) |
| 706 | } |
| 707 | } |
| 708 | |
| 709 | if len(shards) == 0 { |
| 710 | return fmt.Errorf("redis: Watch requires at least one shard") |
| 711 | } |
| 712 | |
| 713 | if len(shards) > 1 { |
| 714 | for _, shard := range shards[1:] { |
| 715 | if shard.Client != shards[0].Client { |
| 716 | err := fmt.Errorf("redis: Watch requires all keys to be in the same shard") |
| 717 | return err |
| 718 | } |
| 719 | } |
| 720 | } |
| 721 | |
| 722 | return shards[0].Client.Watch(ctx, fn, keys...) |
| 723 | } |
| 724 | |
| 725 | // Close closes the ring client, releasing any open resources. |
| 726 | // |
| 727 | // It is rare to Close a Ring, as the Ring is meant to be long-lived |
| 728 | // and shared between many goroutines. |
| 729 | func (c *Ring) Close() error { |
| 730 | return c.shards.Close() |
| 731 | } |