README

Overview

smart-tasks is a very simple task manager (container and scheduler) for NodeJS which can be configured with a configuration file. The base code comes from the following project : (https://github.com/arkerone/smart-container)

🏗️ Installation

$ npm install smart-tasks

🃏 Test

Test are write in test folder with the jest framework from Facebook

$ npm run test

✔️ Features

Define classes or literal objects to task manager,
Define properties to task,
Inject container (from smart-container) in task,
Setting up tasks with a configuration file,
Launch periodic tasks (define with frequency)
single run frequency based task (non-periodic)
single run time based task (non-periodic)

⚙️ TODO

Launch time based tasks (periodic)
Move to TypeScript
Add an ID to task (for serialization ...)
Add Storage integration to store task on disk and restore it

🔧 TO FIX

Service injection in task instead of task injection (see : Construct arguments of TaskDefinition of test container.test.js)

🤔 TO THINK ABOUT

Turn task into promise based object and relaunch it only if the previous one is resolve.
Single run task management (remove it from task container or scheduler task history ?)

🤖 Usage

Create and use the task scheduler without configuration file

Require smart-tasks taskContainer and Scheduler

const st = require('smart-tasks');

Create taskContainer

const taskContainer = st.TaskContainerBuilder.create();

Create and register a new task

/* Create a task class */
class Hello extends Task {
  constructor(container) {
    super(container, 10); // smart-container service container for DI 
    this.msg = 'Hello world!';
  }

  async run() {
    console.log(this.msg);
  }
}
/* Be careful to export your class !*/
module.exports = Hello;

/* Register the task */
taskContainer.register('hello', Hello);

Create task scheduler

const scheduler = st.Scheduler(taskContainer);
scheduler.init();
scheduler.run(1000, null);

The configuration file

Here is a template of a task configuration file tasks.js:

"use strict";
import path from "path";

module.exports = {
    tasks: {
        presence_check: {
            path: path.join(__dirname, '../tasks/PresenceCheckTask.js'),
            frequency: 30 // frequency depend on the loop timeout
        },
        fetch_order: {
            path: path.join(__dirname, '../tasks/FetchOrderTask.js'),
            frequency: 30 // frequency depend on the loop timeout 
        }
    }
};

process.env support

You can use the environment variables:

{
  properties: {
    host: process.env.DB_HOST,
    username: process.env.DB_USER,
    password: process.env.DB_PASS
  },

  tasks: {
        presence_check: {
            path: path.join(__dirname, '../tasks/PresenceCheckTask.js'),
            frequency: 30, // frequency depend on the loop timeout
            constructorArgs: ['%host%', '%username%']
        },
        fetch_order: {
            path: path.join(__dirname, '../tasks/FetchOrderTask.js'),
            frequency: 30 // frequency depend on the loop timeout 
        }
    }
}

The task

The name and path of the task

The object tasks is used to define a collection of tasks. For each task, you must specify its name and the path of its file :

{
  tasks: {
    messagePrinter: {
      path: './MessagePrinter'
    }
  }
}

constructorArgs

you can specify the arguments of the task constructor :

{
  tasks: {
    messagePrinter: {
      path: './MessagePrinter',
      constructorArgs: ['Hello world!']
    }
  }
}

Dependency injection

You can use smart-container container to inject services inside task

this.servicesContainer = ContainerBuilder.build(__dirname, 'config/services.js');
// Init task container with config file
this.taskContainer = TaskContainerBuilder.build(__dirname, 'config/tasks.js', this.servicesContainer);

Usage no npm install needed!