CronScheduler

CronScheduler is a Node.js-based cron scheduler library that allows you to manage, execute, and monitor scheduled jobs. It can handle cron expressions, load jobs from a file, create new jobs, and handle job cancellation or restart.

Features

• Supports cron expressions for flexible scheduling.
• Can schedule jobs based on preset cycles (minute, hour, day, week).
• Jobs can be loaded, created, canceled, or restarted.
• Supports graceful shutdown and reporting of job status.
• Jobs are stored in a local JSON file.

Installation

1. Clone this repository or install it via npm:

npm install echoapi-cron-scheduler

2. If you're using the GitHub repository, run:

git clone https://github.com/Apipo/echoapi-cron-scheduler.git
cd echoapi-cron-scheduler
npm install

Usage

Basic Usage

First, import the CronScheduler class and create an instance:

const CronScheduler = require('echoapi-cron-scheduler');
const scheduler = new CronScheduler();

Creating and Running Jobs

To create a new job, use the createJob method. It will store the job in a JSON file and execute the job based on the schedule provided.

const { option, test_events } = require('./tmp/request');
const { v4: uuidv4 } = require('uuid');

// Set a unique job ID
_.set(option, 'job_id', uuidv4());

// Create the job
scheduler.createJob(option, test_events);

// Load all jobs and start executing them
scheduler.loadJobs();

Start Job with Cron Expression

You can start a job using a cron expression:

scheduler.startJob('* * * * * *', 'exampleJob1', async () => {
    console.log('Executing job every minute...');
});

This will execute the job every minute.

Canceling and Restarting Jobs

To cancel a running job, use cancelJob:

scheduler.cancelJob('exampleJob1');

To restart a job, use restartJob:

scheduler.restartJob('exampleJob1');

Retrieving Job Information

You can retrieve a list of all scheduled jobs, including their current states (e.g., whether they are running):

const allJobs = scheduler.getAllJobs();
console.log(allJobs);

Graceful Shutdown

You can handle a graceful shutdown of all scheduled jobs by listening for SIGINT:

process.on('SIGINT', () => {
    scheduler.gracefulShutdown().then(() => { process.exit(0) });
});

Cron Expression Examples

Here are some cron expression examples you can use to schedule tasks:

• * * * * * * — Every second
• */5 * * * * * — Every 5 seconds
• 0 * * * * * — Every minute
• 0 0 * * * * — Every hour
• 0 0 0 * * * — Every day at midnight
• 0 0 * * 1 * — Every Monday at midnight

License

This project is licensed under the MIT License - see the LICENSE file for details.

### Explanation

1. **`package.json`**:
   - Defines the necessary dependencies (`node-schedule`, `axios`, `lodash`, `cron-parser`, etc.).
   - A basic `start` script that runs the main file (`index.js`).
   - Set the Node.js engine to ensure compatibility with the required Node version.

2. **`README.md`**:
   - Provides a basic overview of the CronScheduler.
   - Describes installation steps and usage examples for creating, managing, and executing cron jobs.
   - Includes explanations for cron expressions and how to handle graceful shutdowns.

### To Use This Project:

1. Clone the repository or install the package using `npm`.
2. Include your scheduler logic and job definitions in the `index.js` or another entry point.
3. Use the provided `createJob`, `startJob`, `cancelJob`, and other methods to interact with scheduled jobs.