使用 Node-Cron 每 10 秒执行一次 Cron 作业

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【中文标题】使用 Node-Cron 每 10 秒执行一次 Cron 作业【英文标题】：Cron Job every 10 seconds with Node-Cron 【发布时间】：2015-07-29 12:18:04 【问题描述】：

我使用 Node-Cron 每 10 秒运行一次 cron 作业。但似乎node-cron存在问题。 https://github.com/ncb000gt/node-cron#cron-ranges

我在04:28:34 提出了请求，但脚本从4:28:40 开始（应该从04:28:44 开始）

我在04:48:58 提出了请求，但脚本从04:49:00 开始（应该从04:49:08 开始）

我在05:03:45 提出了请求，但脚本从05:03:50 开始（应该从04:49:08 开始）

以下是我执行此任务的代码。

router.post("/secret", function (req, res)     console.log("Post request!");    console.log("Start At:" + getUTCDateTime());    function getUTCDateTime()         var date = new Date();        var dateUTC = new Date(date.getUTCFullYear(), date.getUTCMonth(), date.getUTCDate(), date.getUTCHours(), date.getUTCMinutes(), date.getUTCSeconds());        var hour = dateUTC.getHours();        hour = (hour < 10 ? "0" : "") + hour;        var min = dateUTC.getMinutes();        min = (min < 10 ? "0" : "") + min;        var sec = dateUTC.getSeconds();        sec = (sec < 10 ? "0" : "") + sec;        var year = dateUTC.getFullYear();        var month = dateUTC.getMonth() + 1;        month = (month < 10 ? "0" : "") + month;        var day = dateUTC.getDate();        day = (day < 10 ? "0" : "") + day;        return year + "-" + month + "-" + day + " " + hour + ":" + min + ":" + sec; // format: 2015-04-10 11:40:50        function getEndDateTime(startAt, callback)         var date = new Date(startAt);        date.setSeconds(date.getSeconds() + parseInt(callback));        var sec = date.getSeconds();        sec = (sec < 10 ? "0" : "") + sec;        var hour = date.getHours();        hour = (hour < 10 ? "0" : "") + hour;        var min = date.getMinutes();        min = (min < 10 ? "0" : "") + min;        var year = date.getFullYear();        var month = date.getMonth() + 1;        month = (month < 10 ? "0" : "") + month;        var day = date.getDate();        day = (day < 10 ? "0" : "") + day;        return year + "-" + month + "-" + day + " " + hour + ":" + min + ":" + sec; // format: 2015-04-10 11:40:50        function getStartDateTime(startAt, callback)         var date = new Date(startAt);        date.setSeconds(date.getSeconds() - parseInt(callback));        var sec = date.getSeconds();        sec = (sec < 10 ? "0" : "") + sec;        var hour = date.getHours();        hour = (hour < 10 ? "0" : "") + hour;        var min = date.getMinutes();        min = (min < 10 ? "0" : "") + min;        var year = date.getFullYear();        var month = date.getMonth() + 1;        month = (month < 10 ? "0" : "") + month;        var day = date.getDate();        day = (day < 10 ? "0" : "") + day;        return year + "-" + month + "-" + day + " " + hour + ":" + min + ":" + sec; // format: 2015-04-10 11:40:50        function callBackUrl(url, data)        var request = require("request");        request.post(            url,            form: data: data,            function (error, response, body)                 if (!error && response.statusCode == 200)                     console.log(body)                                    );        var startAt = req.body.startAt;    var callback = req.body.callback;    var endAt = req.body.endAt; //2015-05-15 11:23:50    var data = req.body.data;    if (callback == "" || endAt == "" || data == "")        res.end("Params cannot be empty: " + JSON.stringify(req.body));    if (getUTCDateTime() >= endAt)        res.end("Param "endAt" is invalid: " + JSON.stringify(req.body));    var jsonObject = JSON.parse(data); //to get the JSON object of the string    var callbackUrl1 = "http://qa.www.com/index.php/api/default/test/id/1";    var callbackUrl2 = "http://qa.www.com/index.php/api/default/test/id/2";    //cronStartAt = "0 */" + callback + " * * * *"; // only every 1 minute    cronStartAt = "*/" + callback + " * * * * *"; // only every 1 minute    var nowCount = 0;    var CronJob = require("cron").CronJob;    var cron = new CronJob(cronStartAt, function ()         nowCount++;        var tmpStartAt = getStartDateTime(getUTCDateTime(), callback);        var tmpEndAt = getUTCDateTime();        //var tmpStartAt = getUTCDateTime();        //var tmpEndAt = getEndDateTime(tmpStartAt, callback);        //console.log(tmpStartAt + " " + tmpEndAt);        jsonObject.startAt = tmpStartAt;        jsonObject.endAt = tmpEndAt;        data = JSON.stringify(jsonObject);        callBackUrl(callbackUrl1, data);        if (getUTCDateTime() >= endAt)             cron.stop();            console.log("stopped at: " + getUTCDateTime());            console.log("now count: " + nowCount);            , function ()         /* This function is executed when the job stops */        // on crone stop another http call with submitted post data        callBackUrl(callbackUrl2, data);    , true, "America/Los_Angeles");    cron.start();    console.log("Post body: %j", req.body);    res.end("Body: " + JSON.stringify(req.body)););

【问题讨论】：

callback 中的值是多少？还有你如何衡量作业的执行时间？ Can a cron job run every "x" seconds的可能重复 【参考方案1】：

这对我有用 -

    cron.schedule("*/10 * * * * *", function()       console.log("running a task every 10 second");    );

希望这对某人有所帮助。

参考 - https://support.acquia.com/hc/en-us/articles/360004224494-Cron-time-string-format

【讨论】：

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