period

type Policy struct {
	// Policy can be treated as job template of periodic job.
	// The info of policy will be copied into the scheduled job executions for the periodic job.
	ID            string                 `json:"id"`
	JobName       string                 `json:"job_name"`
	CronSpec      string                 `json:"cron_spec"`
	JobParameters map[string]interface{} `json:"job_params,omitempty"`
	WebHookURL    string                 `json:"web_hook_url,omitempty"`
}

type Scheduler interface {
	// Start to serve periodic job scheduling process
	//
	// Returns:
	//  error if any problems happened
	Start() error

	// Stop the working periodic job scheduling process
	//
	// Returns;
	//  error if any problems happened
	Stop() error

	// Schedule the specified cron job policy.
	//
	// policy *Policy           : The job template of the scheduling periodical jobs
	//
	// Returns:
	//  int64 the numeric id of policy
	//  error if failed to schedule
	Schedule(policy *Policy) (int64, error)

	// Unschedule the specified cron job policy.
	//
	// policyID string: The ID of cron job policy.
	//
	// Return:
	//  error if failed to unschedule
	UnSchedule(policyID string) error
}