Node crontab 定时任务的使用

Getting Started

Install node-cron using npm:

$ npm install --save node-cron

Import node-cron and schedule a task:

var cron = require('node-cron');

cron.schedule('* * * * *', () => {
  console.log('running a task every minute');
});

Cron Syntax

This is a quick reference to cron syntax and also shows the options supported by node-cron.

Allowed fields

# ┌────────────── second (optional)
 # │ ┌──────────── minute
 # │ │ ┌────────── hour
 # │ │ │ ┌──────── day of month
 # │ │ │ │ ┌────── month
 # │ │ │ │ │ ┌──── day of week
 # │ │ │ │ │ │
 # │ │ │ │ │ │
 # * * * * * *

Allowed values

field	value
second	0-59
minute	0-59
hour	0-23
day of month	1-31
month	1-12 (or names)
day of week	0-7 (or names, 0 or 7 are sunday)

Using multiples values

You may use multiples values separated by comma:

var cron = require('node-cron');

cron.schedule('1,2,4,5 * * * *', () => {
  console.log('running every minute 1, 2, 4 and 5');
});

Using ranges

You may also define a range of values:

var cron = require('node-cron');

cron.schedule('1-5 * * * *', () => {
  console.log('running every minute to 1 from 5');
});

Using step values

Step values can be used in conjunction with ranges, following a range with ‘/’ and a number. e.g: 1-10/2 that is the same as 2,4,6,8,10. Steps are also permitted after an asterisk, so if you want to say “every two minutes”, just use */2.

var cron = require('node-cron');

cron.schedule('*/2 * * * *', () => {
  console.log('running a task every two minutes');
});

Using names

For month and week day you also may use names or short names. e.g:

var cron = require('node-cron');

cron.schedule('* * * January,September Sunday', () => {
  console.log('running on Sundays of January and September');
});

Or with short names:

var cron = require('node-cron');

cron.schedule('* * * Jan,Sep Sun', () => {
  console.log('running on Sundays of January and September');
});

Cron methods

Schedule

Schedules given task to be executed whenever the cron expression ticks.

Arguments:

• expression string: Cron expression

• function Function: Task to be executed

• options Object: Optional configuration for job scheduling.

Options

• scheduled: A boolean to set if the created task is scheduled. Default true;

• timezone: The timezone that is used for job scheduling. See moment-timezone for valid values.

Example:

var cron = require('node-cron');

 cron.schedule('0 1 * * *', () => {
   console.log('Running a job at 01:00 at America/Sao_Paulo timezone');
 }, {
   scheduled: true,
   timezone: "America/Sao_Paulo"
 });

ScheduledTask methods

Start

Starts the scheduled task.

var cron = require('node-cron');

var task = cron.schedule('* * * * *', () =>  {
  console.log('stopped task');
}, {
  scheduled: false
});

task.start();

Stop

The task won’t be executed unless re-started.

var cron = require('node-cron');

var task = cron.schedule('* * * * *', () =>  {
  console.log('will execute every minute until stopped');
});

task.stop();

Destroy

The task will be stopped and completely destroyed.

var cron = require('node-cron');

var task = cron.schedule('* * * * *', () =>  {
  console.log('will not execute anymore, nor be able to restart');
});

task.destroy();

Validate

Validate that the given string is a valid cron expression.

var cron = require('node-cron');

var valid = cron.validate('59 * * * *');
var invalid = cron.validate('60 * * * *');