queue

Documentation

Index

• type BoundedQueue
  • func NewBoundedQueue(capacity int, onDroppedItem func(item interface{})) *BoundedQueue
  • func (q *BoundedQueue) Capacity() int
  • func (q *BoundedQueue) Produce(item interface{}) bool
  • func (q *BoundedQueue) Resize(capacity int) bool
  • func (q *BoundedQueue) Size() int
  • func (q *BoundedQueue) StartConsumers(num int, callback func(item interface{}))
  • func (q *BoundedQueue) StartConsumersWithFactory(num int, factory func() Consumer)
  • func (q *BoundedQueue) StartLengthReporting(reportPeriod time.Duration, gauge metrics.Gauge)
  • func (q *BoundedQueue) Stop()
• type Consumer
• type ConsumerFunc
  • func (c ConsumerFunc) Consume(item interface{})

Types

type BoundedQueue

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

BoundedQueue implements a producer-consumer exchange similar to a ring buffer queue, where the queue is bounded and if it fills up due to slow consumers, the new items written by the producer force the earliest items to be dropped. The implementation is actually based on channels, with a special Reaper goroutine that wakes up when the queue is full and consumers the items from the top of the queue until its size drops back to maxSize

func NewBoundedQueue

func NewBoundedQueue(capacity int, onDroppedItem func(item interface{})) *BoundedQueue

NewBoundedQueue constructs the new queue of specified capacity, and with an optional callback for dropped items (e.g. useful to emit metrics).

func (*BoundedQueue) Capacity

func (q *BoundedQueue) Capacity() int

Capacity returns capacity of the queue

func (*BoundedQueue) Produce

func (q *BoundedQueue) Produce(item interface{}) bool

Produce is used by the producer to submit new item to the queue. Returns false in case of queue overflow.

func (*BoundedQueue) Resize

func (q *BoundedQueue) Resize(capacity int) bool

Resize changes the capacity of the queue, returning whether the action was successful

func (*BoundedQueue) Size

func (q *BoundedQueue) Size() int

Size returns the current size of the queue

func (*BoundedQueue) StartConsumers

func (q *BoundedQueue) StartConsumers(num int, callback func(item interface{}))

StartConsumers starts a given number of goroutines consuming items from the queue and passing them into the consumer callback.

func (*BoundedQueue) StartConsumersWithFactory

func (q *BoundedQueue) StartConsumersWithFactory(num int, factory func() Consumer)

StartConsumersWithFactory creates a given number of consumers consuming items from the queue in separate goroutines.

func (*BoundedQueue) StartLengthReporting

func (q *BoundedQueue) StartLengthReporting(reportPeriod time.Duration, gauge metrics.Gauge)

StartLengthReporting starts a timer-based goroutine that periodically reports current queue length to a given metrics gauge.

func (*BoundedQueue) Stop

func (q *BoundedQueue) Stop()

Stop stops all consumers, as well as the length reporter if started, and releases the items channel. It blocks until all consumers have stopped.

type Consumer

type Consumer interface {
	Consume(item interface{})
}

Consumer consumes data from a bounded queue

type ConsumerFunc

type ConsumerFunc func(item interface{})

ConsumerFunc is an adapter to allow the use of a consume function callback as a Consumer.

func (ConsumerFunc) Consume

func (c ConsumerFunc) Consume(item interface{})

Consume calls c(item)