schedule-interval.go

// Copyright 2023 schukai GmbH
// SPDX-License-Identifier: AGPL-3.0

package jobqueue

import (
	"fmt"
	"time"
)

// IntervalScheduler is a scheduler that schedules a job at a fixed interval
type IntervalScheduler struct {
	Interval time.Duration
	jobs     map[JobID]StopChan
}

func (s *IntervalScheduler) Schedule(job GenericJob, eventBus *EventBus) error {

	if s.Interval <= 0 {
		return fmt.Errorf("invalid interval: %v", s.Interval)
	}

	if s.jobs == nil {
		s.jobs = make(map[JobID]StopChan)
	}

	id := job.GetID()
	if _, ok := s.jobs[id]; ok {
		return fmt.Errorf("%w: job %s already scheduled", ErrJobAlreadyScheduled, id)
	}

	stopChan := make(StopChan)
	s.jobs[id] = stopChan

	ticker := time.NewTicker(s.Interval)
	go func() {
		for {
			select {
			case <-ticker.C:
				if !job.IsPaused() {
					eventBus.Publish(QueueJob, job)
				}

			case <-stopChan:
				ticker.Stop()
				return
			}
		}
	}()

	return nil
}

func (s *IntervalScheduler) GetType() string {
	return "Interval"
}

func (s *IntervalScheduler) IsAdHoc() bool {
	return false
}

func (s *IntervalScheduler) Cancel(id JobID) error {
	if s.jobs == nil {
		return nil
	}

	if stopChan, ok := s.jobs[id]; ok {
		select {
		case stopChan <- true:
		default:
		}

		delete(s.jobs, id)
	}

	return nil
}

func (s *IntervalScheduler) CancelAll() error {
	if s.jobs == nil {
		return nil
	}

	for _, stopChan := range s.jobs {

		select {
		case stopChan <- true:
		default:
		}
	}

	s.jobs = nil
	return nil
}

func (s *IntervalScheduler) JobExists(id JobID) bool {
	if s.jobs == nil {
		return false
	}

	_, ok := s.jobs[id]
	return ok
}

func (s *IntervalScheduler) GetPersistence() SchedulerPersistence {
	return SchedulerPersistence{
		Type:     s.GetType(),
		Interval: s.Interval,
	}
}