pomelo-scheduler

pomelo-schedule is a schedule tool for nodejs, it's purpose is to provide a product level schedule module which is high efficient and can support large number job schedule.You can As a schedule tool, it support two kinds of trigger: A simple trigger which use a js object and a Cron time trigger which use a Cron time string.

Installation

npm install pomelo-schedule

Schedule simple Job

Simple job will receive a object as a trigger, which take three attributes, a JS function as object, and an object as the parameters in the job.

Simple trigge example

//Fire 10000ms after now, and run 10 times with a 1000ms interval.
var trigger1 = {
  start : Date.now() + 10000, //Start time, use the time in date object
  period : 1000,      //Fire interval, the precision is millisecond
  count : 10          //Fire times, in this case the trigger will fire 10 times.   
}

//Fire right now, and run 10 times with 1000ms interval.
var trigger2 = {
  period : 1000,
  count : 10
}

//Fire right now, and run for ever with 1000ms interval.
var trigger3 = {
  period : 1000
}

//Fire 3000ms after right now, run only once.
var trigger4 = {
  start : Date.now() + 3000;
}

//The job will fire right now, run only once.
var trigger5 = {
}

//Illegal! The 'count' attribute cannot used alone without 'period'.  
var trigger6 = {
  count : 10;
}

Simple job example

var schedule = require('../lib/schedule');

var simpleJob = function(data){
   console.log("run Job :" + data.name);
}

schedule.scheduleJob({start:Date.now(), period:3000, count: 10}, simpleJob, {name: 'simpleJobExample'});

Schedule cron Job

Cron job is the job that use cron trigger, it is just like the simple job, only use the cron trigger instead of simple trigger.

Cron job example

var schedule = require('../lib/schedule');

var cronJob = function(data){
   console.log("run Job :" + data.name);
}

schedule.scheduleJob("0 0/15 8 * * *", cronJob, {name:'cronJobExample'});

Cron Trigger syntax

Cron trigger has 7 fiels, the format is very like the cronTab in linux, only add a second field in the head. The fields and the boundary is as follow:

Exampe of cron tirggers

"0/2 0 8 * * 6"    Fire at every Satuaday at every even seconds of 08:00
"0 30 10 1 4 *"      Fire at 10:30 on 1st of March  
"15 15 15 10 10 *"   Fire at Octorber 10th, at 15:15:15.

Special characters

Pomelo-schedule allow three kinds of spechial characters, they are '-', '/' and '.'.

-: '-' means range. For example, 1-3 in the second field means the seconds 1, 2 and 3

/: means increasement. For exapmle, 1/20 in the second field means 1, 21 and 41 second, and 1/2 means for every odd seconds as 1, 3, 5 ... ...

,: means additional values. For example, 1, 10, 15 in the second field means 1, 10 and 15 second. You can use '-', and '/' with ',', for example, 11,20-22,0/2 in the second filed means 11, 21 and all the even seconds.

Cancel Job

var schedule = require('../lib/schedule');

var simpleJob = function(){
   console.log("run simple Job ");
}

//Add a simple job and save the id 
var id = schedule.scheduleJob({period: 1000}, simpleJob, {});

/**
 * Do some thing else
 */

//CancelJob
schedule.cancelJob(id);

When you cancel a job, it will stop schedule immidiatelly, and delete the job.