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本文主要研究一下dbsync的Schedulable

Schedulable

//Schedulable represent an abstraction that can be schedule
type Schedulable struct {
	URL string
	ID  string
	*contract.Sync
	Schedule *contract.Schedule
	Status   string
	status   uint32
}

//NewSchedulableFromURL create a new scheduleable from URL
func NewSchedulableFromURL(URL string) (*Schedulable, error) {
	result := &Schedulable{}
	resource := url.NewResource(URL)
	err := resource.Decode(result)
	return result, err
}
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Schedulable定义了URL、ID、*contract.Sync、Schedule、Status、status属性；NewSchedulableFromURL方法根据URL来创建Schedulable

Clone

func (s *Schedulable) Clone() *Schedulable {
	return &Schedulable{
		URL:      s.URL,
		ID:       s.ID,
		Sync:     s.Sync.Clone(),
		Schedule: s.Schedule,
		Status:   s.Status,
	}
}
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Clone方法会复制一份Schedulable

Done

//Done return true if schedulable is not running
func (s *Schedulable) Done() {
	atomic.StoreUint32(&s.status, statusScheduled)
}
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Done方法更新status为statusScheduled

IsRunning

//IsRunning return true if schedulable is running
func (s *Schedulable) IsRunning() bool {
	return atomic.LoadUint32(&s.status) == statusRunning
}
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IsRunning方法更新status为statusRunning

ScheduleNexRun

//ScheduleNexRun schedules next run
func (s *Schedulable) ScheduleNexRun(baseTime time.Time) error {
	return s.Schedule.Next(baseTime)
}
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ScheduleNexRun方法执行Schedule.Next(baseTime)

Init

//Init initializes scheduleable
func (s *Schedulable) Init() error {
	if s.ID == "" {
		s.ID = uRLToID(s.URL)
	}
	now := time.Now()
	if s.Schedule == nil {
		return nil
	}

	if s.Schedule.Frequency != nil && s.Schedule.Frequency.Value == 0 {
		s.Schedule.Frequency.Value = 1
	}
	if s.Schedule.NextRun == nil {
		if s.Schedule.Frequency != nil {
			s.Schedule.NextRun = &now
		} else {
			return s.Schedule.Next(now)
		}
	}
	return nil

}
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Init方法执行Schedulable的初始化

Validate

//Validate checks if Schedulable is valid
func (s *Schedulable) Validate() error {
	if s.Schedule == nil {
		return fmt.Errorf("schedule was emtpy")
	}
	if s.Schedule.Frequency == nil && s.Schedule.At == nil {
		return fmt.Errorf("schedule.Frequency and schedule.At were emtpy")
	}
	if s.ID == "" {
		return fmt.Errorf("ID were emtpy")
	}
	return nil
}
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Validate方法校验Schedule、Schedule.Frequency、Schedule.At、ID值

小结

dbsync的Schedulable定义了URL、ID、*contract.Sync、Schedule、Status、status属性，它提供了Clone、Done、IsRunning、ScheduleNexRun、Init、Validate方法。

doc

• dbsync