This is a simple little Queue with blocking pop abilities built in golang

queue.go

package queue

import "sync"

type Queue struct {
	q         []int
	size      int
	lock      *sync.Mutex
	addlisten chan int
}

func NewQueue() *Queue {
	q := Queue{size: 0, lock: new(sync.Mutex)}
	q.Clear()
	return &q
}

func (q *Queue) Block() {
	if q.size <= 0 {
		<-q.addlisten
	}
}

func (q *Queue) Added() {
	q.addlisten <- 1
}

func (q *Queue) LPush(i int) {
	q.lock.Lock()
	newz := []int{i}
	copy(newz, q.q)
	q.q = newz
	q.size += 1
	q.Added()
	q.lock.Unlock()
}

func (q *Queue) RPush(i int) {
	q.lock.Lock()
	q.q = append(q.q, i)
	q.size += 1
	q.Added()
	q.lock.Unlock()
}

func (q *Queue) BRPop() int {
	q.Block()
	return q.RPop()
}

func (q *Queue) BLPop() int {
	q.Block()
	return q.LPop()
}

func (q *Queue) RPop() int {
	q.lock.Lock()
	if q.size <= 0 {
		return -1
	}
	value := q.q[len(q.q)-1]
	q.q = q.q[:len(q.q)-1]
	q.size -= 1
	q.lock.Unlock()
	return value
}

func (q *Queue) LPop() int {
	q.lock.Lock()
	if q.size <= 0 {
		return -1
	}
	value := q.q[0]
	q.q = q.q[1:]
	q.size -= 1
	q.lock.Unlock()
	return value
}

func (q *Queue) Clear() {
	q.q = make([]int, 0)
}