fix: finalize growth cost controls

internal/growthreport/coordinator.go

@@ -18,19 +18,18 @@ type CoordinatorConfig struct {
 	MaxConcurrent                                               int
 }
 type Coordinator struct {
-	redis     *redis.Client
-	config    CoordinatorConfig
-	mu        sync.Mutex
-	counters  map[string]int64
-	expiries  map[string]time.Time
-	semaphore chan struct{}
+	redis    *redis.Client
+	config   CoordinatorConfig
+	mu       sync.Mutex
+	counters map[string]int64
+	expiries map[string]time.Time
 }
 
 func NewCoordinator(client *redis.Client, config CoordinatorConfig) *Coordinator {
 	if config.MaxConcurrent < 1 {
 		config.MaxConcurrent = 4
 	}
-	return &Coordinator{redis: client, config: config, counters: map[string]int64{}, expiries: map[string]time.Time{}, semaphore: make(chan struct{}, config.MaxConcurrent)}
+	return &Coordinator{redis: client, config: config, counters: map[string]int64{}, expiries: map[string]time.Time{}}
 }
 func (c *Coordinator) AllowCreate(ctx context.Context, userID int64, now time.Time) error {
 	return c.increment(ctx, fmt.Sprintf("growth:create:%d:%s", userID, now.UTC().Format("200601021504")), c.config.CreatePerMinute, time.Minute, now)
@@ -66,19 +65,30 @@ func (c *Coordinator) incrementRedis(ctx context.Context, key string, amount, li
 	return nil
 }
 func (c *Coordinator) Enter(ctx context.Context) (func(), error) {
-	select {
-	case c.semaphore <- struct{}{}:
-		return func() { <-c.semaphore }, nil
-	case <-ctx.Done():
-		return nil, ctx.Err()
+	if c.redis == nil {
+		return nil, ErrBudgetExhausted
+	}
+	acquire := redis.NewScript(`local v=redis.call('INCR',KEYS[1]);if v==1 then redis.call('PEXPIRE',KEYS[1],ARGV[2]) end;if v>tonumber(ARGV[1]) then redis.call('DECR',KEYS[1]);return 0 end;return 1`)
+	for {
+		ok, err := acquire.Run(ctx, c.redis, []string{"growth:ai:concurrency"}, c.config.MaxConcurrent, (3 * time.Minute).Milliseconds()).Int()
+		if err != nil {
+			return nil, ErrBudgetExhausted
+		}
+		if ok == 1 {
+			return func() {
+				releaseCtx, cancel := context.WithTimeout(context.Background(), time.Second)
+				defer cancel()
+				script := redis.NewScript(`local v=tonumber(redis.call('GET',KEYS[1]) or '0');if v>0 then return redis.call('DECR',KEYS[1]) end return 0`)
+				_ = script.Run(releaseCtx, c.redis, []string{"growth:ai:concurrency"}).Err()
+			}, nil
+		}
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-time.After(100 * time.Millisecond):
+		}
 	}
 }
-func (c *Coordinator) Publish(ctx context.Context, reportID string) {
-	if c.redis != nil {
-		_ = c.redis.LPush(ctx, "growth:jobs", reportID).Err()
-	}
-}
-
 func (c *Coordinator) increment(ctx context.Context, key string, limit int64, ttl time.Duration, now time.Time) error {
 	return c.incrementBy(ctx, key, 1, limit, ttl, now)
 }