Vf-tasks-queue NPM

Tasks Queue

This module is an abstraction of RabbitMQ.

It supports both promises and callbacks.

Install

npm install --save vf-tasks-queue

API

TaskQueueLib.connect(options, callback)

Returns a task queue, ready to send and process tasks.

Parameters

options (Object): Tasks queue configuration
- prefix (Object): Appends a string to all task types to create a namespace. * rabbitmq (Object): Configuration to connect to RabbitMQ server.
  - host (String): Server host.
  - port (String): Server port.
  - user (String): Server user.
  - password (String): Server password.

tasksQueue.send(type, data, callback)

Stores a new task in the queue.

Parameters

type (String): Task type, this is used to match task processors.
data (Object): An data object that will be sent to processor when takes this task.

tasksQueue.process(type, processor, concurrency)

Takes tasks and process them.

Parameters

options (String): Options to start processing tasks.
- type (String): Task type, this is used to fetch only this type of tasks.
- concurrency (Integer): An integer that indicates the number of tasks that can be processed at the same time. Defaults to 1.
processor (Function): A function that will process a task. This function will receive 1 parameter: data. You sould return a promise, otherwise task won't be marked as resolved and will be processed again.

tasksQueue.clearQueue(type, callback)

Removes all unprocessed tasks of a type.

Parameters

type (String): Task type, this is used to remove only this type of tasks.

tasksQueue.close(callback)

Closes the connection with database.

Example:

config.js

module.exports = {
  prefix: 'queue',
  rabbitmq: {
    host: 'localhost'
  }
};

tasks_sender.js

const config = require('config.js');
const tasksQueueConnector = require('vf-tasks-queue');
const taskType = 'test-task';
const taskData = {
  name: 'Chewbacca'
};

tasksQueueConnector.connect(config)
  .then(tasksQueue => {
    tasksQueue.send(taskType, taskData)
  });

tasks_processor.js

const config = require('config.js');
const tasksQueueConnector = require('vf-tasks-queue');
const taskType = 'test-task';

const processor = (data, callback) => {
  console.log(data.name); // Prints "Chewbacca"
  return Promise.resolve();
}

const options = {
  type: taskType,
  concurrency: 1  
};

tasksQueueConnector.connect(config)
  .then(tasksQueue => {
    tasksQueue.process(options, processor);
  });