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A Node.js library for accessing Amazon SWF

A Node.js library for accessing Amazon Simple Workflow (SWF)

aws-swf provides high-level classes to build Amazon Simple Workflows using Node.js.

It is built on top of the official Node.js aws-sdk for low-level API calls. You can find the full API reference here.

npm install aws-swf


The AWS SDK is sufficient to register SWF objects, since those are just direct API calls. (You can also register them through the AWS console.)

You can run the following example to register the objects used in the following examples :

Example to register "test-domain", "simple-activity" and "simple-workflow"

An ActivityPoller will wait for new tasks from SWF, and emit an activityTask event. The event receives an instance of ActivityTask, which makes it easier to send the response to SWF.

This example starts an Activity Worker which completes immediatly.

The Decider class will wait for new decision tasks from SWF, and emit a decisionTask event. The event receives an instance of DecisionTask, composed of :

  • an EventList instance, to query the state of the workflow
  • a DecisionResponse instance, to prepare the decider response with decisions

Simple decider worker example : decision worker, which schedules an activity task, then stop the workflow.

To start a workflow, call the start method on a Workflow instance. This call will return a WorkflowExecution instance, which you can use to signal or terminate a workflow.

Sometimes you may want to configure the AWS SDK instance. A possible reason is to set a specific region for aws-swf. Because Node.js allows multiple instances of the same package for maximal compatibility among libraries, you would need to do something similar to:

var AWS = require('./node_modules/aws-swf/node_modules/aws-sdk/lib/aws');

Instead, you simlpy need to do:

var AWS = require('aws-swf').AWS;

An example use case would be:

var AWS = require('aws-swf').AWS;
AWS.config = new AWS.Config({
  region: process.env.AWS_REGION || 'us-west-2',
  apiVersions: {
    swf: '2012-01-25'

The API documentation is available online at

To rebuild the documentation, install jsdoc, then :

jsdoc lib/*.js -d apidoc

Tests can be executed with Mocha :

$ mocha

To get the coverage, run :

$ ./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha

Then open coverage/lcov-report/index.html

To send the coverage to coveralls, I run locally (I don't know why travis-ci after-script doesn't work...):

$ NODE_ENV=test ./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/ | COVERALLS_REPO_TOKEN=xxxx ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage

MIT License