Stupidly simple task manager to schedule concurrent tasks

task_manager.go

package task

import "sync"

type TaskManager struct {
	taskQueueLock sync.Mutex
	taskQueue []func()
	runningTasks int
	maxConcurrentTasks int
}

func NewTaskManager(maxConcurrentTasks int) *TaskManager {
	return &TaskManager{
		taskQueue: []func(){},
		runningTasks: 0,
		maxConcurrentTasks: 0,
	}
}

func (tm *TaskManager) AddTask(task func())  {
	tm.taskQueueLock.Lock()
	tm.taskQueue = append(tm.taskQueue, task)
	tm.taskQueueLock.Unlock()
	go tm.tick()
}

func (tm *TaskManager) tick()  {
	if tm.runningTasks >= tm.maxConcurrentTasks {
		// cancel if there's already a reached max of concurrent tasks
		return
	}

	tm.taskQueueLock.Lock()

	if len(tm.taskQueue) == 0 {
		// don't do anything, queue is empty
		tm.taskQueueLock.Unlock()
		return
	}

	// get the first task
	var task = tm.taskQueue[0]
	// pull the task so that it can't be done again
	tm.taskQueue = removeIndex(tm.taskQueue, 0)
	// run the task, and tick again
	tm.runningTasks++
	tm.taskQueueLock.Unlock()
	go func() {
		task()
		tm.runningTasks--
		// tick again
		tm.tick()
	}()
	go tm.tick()
}

func removeIndex(s []func(), index int) []func() {
	ret := make([]func(), 0)
	ret = append(ret, s[:index]...)
	return append(ret, s[index+1:]...)
}