JobManager.js

if (Meteor.isServer) {
    JobManager = {};
    let jobInfoMap = {};

    JobManager.init = function(config) {
        let maxJobCount = 5;
        Meteor.setInterval(() => {
            let runningJobs = _BackgroundJob.find({ status: constant['STATUS_STARTED'] }).fetch();
            let runningJobsCount = runningJobs.length;
            console.log('Running Jobs Count: ', runningJobsCount);
            for (let i = runningJobsCount; i < maxJobCount; i++) {
                pickJob();
            }
        }, 5000);

    };

    JobManager.register = function(name, jobFunction, customJobCompletedPoint) {
        jobInfoMap[name] = {
            jobFunction: jobFunction,
            customJobCompletedPoint: customJobCompletedPoint || false
        };
    };

    JobManager.run = function(obj) {
        _BackgroundJob.insert({
            type: obj.type,
            priority: obj.priority,
            status: constant['STATUS_NOT_STARTED'],
            created: new Date(),
            arguments: obj.arguments
        });
    };

    JobManager.markJobFinished = function(jobId) {
        _BackgroundJob.update({
            _id: jobId
        }, {
            $set: {
                status: constant['STATUS_SUCCESS']
            }
        });
    };

    function pickJob() {
        let job;
        try {
            job = _BackgroundJob.find({
                status: constant['STATUS_NOT_STARTED']
            }, {
                sort: {
                    'created': 1
                },
                limit: 1
            }).fetch()[0];
            if (job) {
                console.log('created job: ', job._id);
                _BackgroundJob.update({
                    _id: job._id
                }, {
                    $set: {
                        'status': constant['STATUS_STARTED']
                    }
                });
                var func = jobInfoMap[job.type].jobFunction;
                var _arguments = job.arguments;
                _arguments.push(job._id);
                func.apply(null, _arguments);
                if (!jobInfoMap[job.type].customJobCompletedPoint) {
                    _BackgroundJob.update({
                        _id: job._id
                    }, {
                        $set: {
                            status: constant['STATUS_SUCCESS']
                        }
                    });
                }
            }
        } catch (err) {
            console.error(err);
            _BackgroundJob.update({
                _id: job._id
            }, {
                $set: {
                    status: constant['STATUS_FAILURE']
                }
            });
        }
    }
}