simple-job-dispatcher

Description

Curent Version 0.0.3

simple-job-dispatcher is a simple in-process job dispatcher. This is probably useful only if the job you going to do is async, as all jobs are still executed in single event-loop. If you job is synchronus, it might be easier just to use a simple loop.

Requirements

• node.js -- v10.16.0 or newer, older version probably works but only tested on 10.16

Installation

npm install simple-job-dispatcher

Example

There is an exmaple.js provided, which also shown below.

const dispatcher_factory = require('simple-job-dispatcher');

const dispatcher = new dispatcher_factory();

// define a worker function that process job
// in this case it just display job detail and return after 5s
const worker = (job, done) => {
    console.log(`received job: ${JSON.stringify(job)}`);
    setTimeout(done, 5000);
};

// initialize dispatcher with max parallel processing of 2 jobs
dispatcher.init(
    2,
    worker
);

// use getStats to check dispatcher status
setInterval(() => {
    console.log(dispatcher.getStats());
}, 1000);

// exit the app after 11s
setTimeout(process.exit, 11000, 0);

// push some jobs
dispatcher.addJob({
    id: 1,
    data: "something"
}, () => console.log('job done'));

dispatcher.addJob({
    id: 2,
    data: "something"
}, () => console.log('job done'));

dispatcher.addJob({
    id: 3,
    data: "something"
}, () => console.log('job done'));

dispatcher.addJob({
    id: 4,
    data: "something"
}, () => console.log('job done'));

Running it shall give you result like below

% node example.js 
received job: {"id":1,"data":"something"}
received job: {"id":2,"data":"something"}
{ queue_count: 2, loading: 2 }
{ queue_count: 2, loading: 2 }
{ queue_count: 2, loading: 2 }
{ queue_count: 2, loading: 2 }
job done
received job: {"id":3,"data":"something"}
job done
received job: {"id":4,"data":"something"}
{ queue_count: 0, loading: 2 }
{ queue_count: 0, loading: 2 }
{ queue_count: 0, loading: 2 }
{ queue_count: 0, loading: 2 }
{ queue_count: 0, loading: 2 }
job done
job done
{ queue_count: 0, loading: 0 }