146 lines
4.3 KiB
Go
146 lines
4.3 KiB
Go
package service
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import (
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"context"
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"errors"
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"fmt"
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"os"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/redis/go-redis/v9"
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)
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type localRateEntry struct {
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started time.Time
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count int
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}
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type runtimeCoordinator struct {
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redis *redis.Client
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instanceID string
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localMu sync.Mutex
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localRate map[string]localRateEntry
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}
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var fixedWindowScript = redis.NewScript(`
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local count = redis.call('INCR', KEYS[1])
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if count == 1 then redis.call('PEXPIRE', KEYS[1], ARGV[1]) end
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return count
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`)
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var acquireSlotScript = redis.NewScript(`
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redis.call('ZREMRANGEBYSCORE', KEYS[1], '-inf', ARGV[1])
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if redis.call('ZCARD', KEYS[1]) >= tonumber(ARGV[3]) then return 0 end
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redis.call('ZADD', KEYS[1], ARGV[2], ARGV[4])
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redis.call('PEXPIRE', KEYS[1], ARGV[5])
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return 1
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`)
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func newRuntimeCoordinator(dialect string) (*runtimeCoordinator, error) {
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coordinator := &runtimeCoordinator{instanceID: newID(), localRate: map[string]localRateEntry{}}
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redisURL := strings.TrimSpace(os.Getenv("REDIS_URL"))
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if redisURL == "" {
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if dialect == "postgres" {
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return coordinator, errors.New("PostgreSQL 多实例模式必须配置 REDIS_URL，用于限流、并发和熔断协调")
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}
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return coordinator, nil
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}
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options, err := redis.ParseURL(redisURL)
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if err != nil {
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return coordinator, fmt.Errorf("REDIS_URL 无效：%w", err)
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}
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coordinator.redis = redis.NewClient(options)
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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defer cancel()
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if err := coordinator.redis.Ping(ctx).Err(); err != nil {
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return coordinator, fmt.Errorf("Redis 不可用：%w", err)
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}
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return coordinator, nil
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}
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func (c *runtimeCoordinator) allow(ctx context.Context, key string, limit int, window time.Duration) (bool, error) {
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if c.redis != nil {
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count, err := fixedWindowScript.Run(ctx, c.redis, []string{"canvas:rate:" + key}, window.Milliseconds()).Int64()
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return count <= int64(limit), err
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}
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c.localMu.Lock()
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defer c.localMu.Unlock()
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now := time.Now()
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entry := c.localRate[key]
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if entry.started.IsZero() || now.Sub(entry.started) >= window {
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c.localRate[key] = localRateEntry{started: now, count: 1}
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return true, nil
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}
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if entry.count >= limit {
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return false, nil
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}
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entry.count++
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c.localRate[key] = entry
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return true, nil
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}
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func (c *runtimeCoordinator) acquire(ctx context.Context, scope string, limit int, ttl time.Duration) (func(), bool, error) {
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if c.redis == nil {
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return func() {}, true, nil
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}
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// 有过期分数的有序集合避免实例崩溃后永久占槽，业务数据库仍保存任务与账本真相。
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key := "canvas:slots:" + scope
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token := c.instanceID + ":" + newID()
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now := time.Now()
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ok, err := acquireSlotScript.Run(ctx, c.redis, []string{key}, now.UnixMilli(), now.Add(ttl).UnixMilli(), limit, token, (ttl + time.Minute).Milliseconds()).Int()
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if err != nil || ok != 1 {
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return nil, false, err
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}
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return func() { _ = c.redis.ZRem(context.Background(), key, token).Err() }, true, nil
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}
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func (c *runtimeCoordinator) circuitOpen(ctx context.Context, channelID string) (bool, error) {
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if c.redis == nil || strings.TrimSpace(channelID) == "" {
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return false, nil
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}
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count, err := c.redis.Exists(ctx, "canvas:circuit:open:"+channelID).Result()
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return count > 0, err
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}
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func (c *runtimeCoordinator) recordChannelResult(ctx context.Context, channelID string, failed bool) {
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if c.redis == nil || strings.TrimSpace(channelID) == "" {
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return
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}
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failureKey := "canvas:circuit:failures:" + channelID
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openKey := "canvas:circuit:open:" + channelID
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if !failed {
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_ = c.redis.Del(ctx, failureKey, openKey).Err()
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return
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}
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count, err := c.redis.Incr(ctx, failureKey).Result()
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if err != nil {
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return
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}
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_ = c.redis.Expire(ctx, failureKey, time.Minute).Err()
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if count >= int64(envInt("CANVAS_CHANNEL_CIRCUIT_FAILURES", 5)) {
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_ = c.redis.Set(ctx, openKey, "1", time.Duration(envInt("CANVAS_CHANNEL_CIRCUIT_SECONDS", 60))*time.Second).Err()
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}
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}
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func envInt(key string, fallback int) int {
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value, err := strconv.Atoi(strings.TrimSpace(os.Getenv(key)))
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if err != nil || value <= 0 {
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return fallback
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}
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return value
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}
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func (s *Service) ValidateRuntime() error {
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return s.runtimeErr
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}
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func (s *Service) AllowRequest(ctx context.Context, key string, limit int, window time.Duration) (bool, error) {
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if s.coordinator == nil {
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return false, errors.New("运行时协调器未初始化")
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}
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return s.coordinator.allow(ctx, key, limit, window)
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}
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