node-cron可以每分钟运行几秒吗

Question

我可以安排node-cron每分钟或每30秒运行一次(参见代码)，但我希望它每分钟运行一次。原因是我也有另一个任务每小时调度一次，我希望在每小时任务运行之前完成分钟任务。

分钟任务将Modbus值和日志读取到MongoDB数据库中。每小时任务获取所有记录并将它们发布到REST端点，并记录同步时间。因为这两个任务在整点同时运行，所以POST中遗漏了一个值。

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

cron.schedule('* * * * *', () => { // Every minute
    console.log("--------------------------------------------------");
    console.log('Cron Task - Time: ' + (new Date()));
    console.log("--------------------------------------------------");
});

cron.schedule('*/30 * * * * *', () => { // Every 30 seconds
    console.log("--------------------------------------------------");
    console.log('Cron Task - Time: ' + (new Date()));
    console.log("--------------------------------------------------");
});

Answer 1

通过一些尝试，我发现了一个错误.下面的代码每分钟运行一次：

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

cron.schedule('30 0-59 * * * *', () => { // Every minute offset 30 seconds
    console.log("--------------------------------------------------");
    console.log('Cron Task - READ - Time: ' + (new Date()));
    console.log("--------------------------------------------------");
});

/*
--------------------------------------------------
Cron Task - READ - Time: Tue Oct 01 2019 10:09:30 GMT-0400 (EDT)
--------------------------------------------------
--------------------------------------------------
Cron Task - READ - Time: Tue Oct 01 2019 10:10:30 GMT-0400 (EDT)
--------------------------------------------------
--------------------------------------------------
Cron Task - READ - Time: Tue Oct 01 2019 10:11:30 GMT-0400 (EDT)
--------------------------------------------------
--------------------------------------------------
Cron Task - READ - Time: Tue Oct 01 2019 10:12:30 GMT-0400 (EDT)
--------------------------------------------------
*/

我最终让读取任务每分钟运行一分钟，但使每小时同步任务在一小时后30秒运行：

var cron = require('node-cron');
const schedule_read = require('./schedule_read');
const schedule_sync = require('./schedule_sync');

cron.schedule('* * * * *', () => { // Every minute
    console.log("--------------------------------------------------");
    console.log('Cron Task - READ - Time: ' + (new Date()));
    console.log("--------------------------------------------------");
    schedule_read.read();
});

cron.schedule('30 0 0-23 * * *', () => { // Every hour offset by 30 seconds
    console.log("--------------------------------------------------");
    console.log(' Cron Task - SYNC - Time: ' + (new Date()));
    console.log("--------------------------------------------------");
    schedule_sync.sync();
});

Answer 2

你应该控制你的时间表，告诉CPU运行之后，首先运行30秒，然后运行一分钟，最后一个小时的时间表。在接下来的一分钟和几个小时的时间里，所有的事情都是可以的，并自动运行它。

var cron = require('node-cron');
var minutsBoolean = false;
var hourBoolean = false;

function oneHourIsRun() {
    cron.schedule('* 0-23 * * *', () => { // Every hour
        console.log("--------------------------------------------------");
        console.log('Cron Task - Time: ' + (new Date()));
        //hourly task grabs all of the records and POSTs them to a REST endpoint and logs the sync time
        console.log("--------------------------------------------------");
    });
}
function oneMinutsIsRun() {
    cron.schedule('* * * * *', () => { // Every one minuts, runnig after 30 second
        console.log("--------------------------------------------------");
        console.log('Cron Task - Time: ' + (new Date()));
        //minute task reads Modbus values and logs to a MongoDB database .then() {below code in here}
        if (!hourBoolean) {
            oneHourIsRun();
            hourBoolean = true;
        }
        console.log("--------------------------------------------------");
    });
}

cron.schedule('30 * * * * *', () => { // Every 30 second, */30 ruunig in 30 minuts of hour not 30 secend
    console.log("--------------------------------------------------");
    console.log('Cron Task - Time: ' + (new Date()));
    if (!minutsBoolean) {
        oneMinutsIsRun();
        minutsBoolean = true;
    }
    console.log("--------------------------------------------------");
});