Configure and execute machines

machine (runner)

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A runner for machines written in JavaScript. Machines are atomic, context-free bits of code which conform to the machine specification: an open standard for functions and subroutines.

Chances are you don't need to use this module directly- see About This Module below for info.


With node installed:

# Get the machine runner 
$ npm install machine --save

If you're interested in contributing to the machine specification, please request to join the project's Google Group and introduce yourself to the rest of the core team. In the mean time, you can check out the tests for information on how to use all the lower-level features of this module. There is also a guide for direct usage of this module in docs/ Note that you can run the tests for this module using npm test, and that we're using a preinstall script to generate a recursive dependency report (via the licensing module by 3rdEden).

Make sure you've read the issue submission guidelines from Sails before opening a new issue - the node-machine project uses the same rules.

Click here to search/post issues in this repository.

Before you read any further, let's stop and make sure you're in the right place. The documentation in this README file is for low-level usage of machine, the JavaScript machine runner. You don't need to use this module directly unless you're building machines.

You can find more information about the node-machine project on There you'll also find a short video from the introductory talk at, an up-to-date list of all available machines on NPM, and standardized documentation pages with code examples you can copy and paste into your Node.js app (e.g. Github.createRepo()).

Building a machinepack? Here are some tips:

  • Start with tutorial for implementors
  • Join the newsgroup for the machine specification to get help from other machine implementors
  • Don't forget to add the "repository" key to your package.json file so folks can find your source code (this enables the View Source button in the generated documentation on
  • Hit up @mikermcneil on Twitter and let me know what you're working on!

This is a low-level module for building, configuring, and running machines.

Normal users of machines won't interact with this module directly very often-- however it is a dependency of every machinepack. Its full list of responsibilities includes exposing the conventional machine usage, a .exec() helper (for familiarity with Waterline), as well as validating input expectations, coercing return values from exits, and more.

The .build() method accepts a machine definition object and returns a new ready-to-use machine instance function. The .pack() method accepts a filesystem path and returns a ready-to-use machinepack obtained by requiring the module located at the path, loading its machine definitions into live machines (calling .build() on each definition), and validating that everything is up to spec.

So when you require a machinepack from NPM like so:

var Github = require('machinepack-github');

what's actually happening is that the index.js file in the machinepack module is calling .pack() and returning an object of ready-to-go machine instances.

There are only two use-cases for requiring this module directly:

Note that this is taken care of for you if you used the Yeoman generator to create your machinepack.

If you're implementing a machinepack, you'll need to use this module to .pack() your machines in your index.js file. Here's an example of an index.js file (this example happens to come from machinepack-urls- your pack's index.js file should always look the same, no matter what).

Normally, if you want to use a machine from inside of one of your machines, you just install and require the other machinepack in your pack and use it just like you would in app-level code. But if you want to use another machine in the same pack, or you want the machine to call itself recursively, you should use this module directly. You can read more information on this in the FAQ for implementors.

You can use it anywhere you like! For instance, you might want to implement a one-off machine in your app, perhaps to take advantage of caching or type-checking this module provides.

If you're using Sails, check out sails-hook-machines, a hook which allows you to use custom closed-source machines in your Sails app by dropping files into the api/machines/ folder.


© 2014 Mike McNeil; © 2015 The Treeline Company