capacity

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v1.0.0 Latest Latest Go to latest Published: Mar 7, 2026 License: MIT Imports: 4 Imported by: 0

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var ErrQueueClosed = errors.New("capacity queue closed")

ErrQueueClosed is returned when the queue is shut down.

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type Limiter struct {
	// contains filtered or unexported fields
}

Limiter enforces concurrent execution capacity.

Semantics:

capacity > 0  → bounded capacity
capacity == 0 → no capacity (reject all)
capacity < 0  → unlimited capacity

func NewLimiter(capacity int) *Limiter

NewLimiter creates a new capacity limiter.

func (l *Limiter) Capacity() int

Capacity returns the configured capacity limit. Returns negative values to indicate unlimited capacity.

func (l *Limiter) InUse() int

InUse returns the current number of acquired capacity units.

func (l *Limiter) Release()

Release releases one unit of capacity.

func (l *Limiter) TryAcquire() bool

TryAcquire attempts to acquire one unit of capacity. Returns true if capacity was acquired, false otherwise.

type Queue struct {
	// contains filtered or unexported fields
}

Queue provides FIFO (First In, First Out) waiting for capacity. When capacity becomes available, waiters are released in the order they arrived.

func NewQueue() *Queue

NewQueue creates a new FIFO capacity queue.

func (q *Queue) Close()

Close shuts down the queue and wakes all waiting goroutines.

func (q *Queue) Release()

Release wakes exactly one waiter (FIFO order).

func (q *Queue) Wait(ctx context.Context) error

Wait blocks the caller until either: - The caller is released (capacity became available), or - ctx is canceled

Returns ErrQueueClosed if the queue is shut down.