task-container

task-container

Node task runner. Allows user to create and run Node task in separate process.

Example

childTask.js

module.exports = (data, callback) => {
  setTimeout(() => {
    callback(null, data);
  }, 5000)
}

main.js

const TaskContainer = require('task-container');

let tasker = new TaskContainer();
tasker.run(require.resolve('./childTask'), {test: 'hello world'}, (err, result) => {
  if(error != null) {
    console.log(err);
  } else {
    console.log(result);
  }
});

output
{test:'hello world'}

API

new TaskContainer([options])

options

{
  maxHandlers: [number], //default: require('os').cpus().length
  maxCallsPerHandler: [number], //default: Infinity
  debug: [boolean] //default: false
}

• maxHandlers

  Number of child processes to spawn for handling tasks. If all child processes are currently busy the task will be queued and handled as soon as a handler is free. Task are processed in FIFO order.

• maxCallsPerHandler

  Number of times to call a child task before recycling the process (killing current child process and starting a new one). This can be used to manage memory leaks until they can be fixed.

• debug

  Set this to true if you want the handlers to add --debug-brk=[port] before each child process. This can be used to attach to the child processes and debug if necessary.

taskContainer.run(script, [data], callback)

script
This is the path to the module you wish to run as a task. This script should export a method which takes an object as it's first parameter and a callback as the second.
Example:

module.exports = (data, callback) => {
  //do work here
  callback([error], [result]);
}

data
Object you wish to be passed to the task.

callback
Method which gets called when task has completed.

Advanced

*To receive messages from the child process that do not trigger the callback function you need to add a result.ignore=true property to what is passed to process.send if trying to perform IPC communication.