go cron源码

cron源码

cron在线表达式

推荐使用在线工具来看自己写的 cron 对不对，简单的表达式直接写一般问题不大。这里推荐 crontab.guru，可以通过可视化的方式来查看你编写的定时规则。

cron源码包

创建任务

 import "github.com/robfig/cron/v3"
 job := cron.new()
 job.AddFunc("*/1 * * * * *",func(){
     fmt.println("hello")
 })
 job.Start()

核心数据结构

// Cron keeps track of any number of entries, invoking the associated func as
// specified by the schedule. It may be started, stopped, and the entries may
// be inspected while running.
type Cron struct {
	entries   []*Entry
	chain     Chain
	stop      chan struct{}
	add       chan *Entry
	remove    chan EntryID
	snapshot  chan chan []Entry
	running   bool
	logger    Logger
	runningMu sync.Mutex
	location  *time.Location
	parser    ScheduleParser
	nextID    EntryID
	jobWaiter sync.WaitGroup
}

// EntryID identifies an entry within a Cron instance
type EntryID int

// Entry consists of a schedule and the func to execute on that schedule.
type Entry struct {
	// ID is the cron-assigned ID of this entry, which may be used to look up a
	// snapshot or remove it.
	ID EntryID

	// Schedule on which this job should be run.
	Schedule Schedule

	// Next time the job will run, or the zero time if Cron has not been
	// started or this entry's schedule is unsatisfiable
	Next time.Time

	// Prev is the last time this job was run, or the zero time if never.
	Prev time.Time

	// WrappedJob is the thing to run when the Schedule is activated.
	WrappedJob Job

	// Job is the thing that was submitted to cron.
	// It is kept around so that user code that needs to get at the job later,
	// e.g. via Entries() can do so.
	Job Job
}