This is a NodeJS framework for constructing deciders for Amazon's Simple Workflow Service (SWF). It allows you to configure your decisions through a combination of Pipelines and Tasks (see below), the end result being complete separation between your decider, your activity poller (worker), and the actual activities.

This is a modified version of the great swiffer-framework by Jason Raede of Dispatch Me. This fork attempts to maintain as much backwards compatibility as possible.

Installation

npm install -s swiffer-decider

Usage

Import the framework:

const swf = require('swiffer-decider');

Define your workflow as an ordered list of tasks, possibly including logic:

var workflowPipeline = swf.createSeriesPipeline([
  // Downloads all the files from the S3 bucket into a local store, and
  // returns as output the list of downloaded files.
  swf.createActivityTask({
    name: "Download files",
    activityVersion: "beta",
    input: {
      source: "s3://my-bucket/incoming"
    }
  }),
  // For each downloaded file, process it.
  swf.generateTask(function (eventlist) {
    var tasks = eventlist.filter(function (evt) {
      // Find the completed activity event for the "Download files" task.
      return evt.name === "Download files" && evt.isCompleted();
    })
    // Get the result from that activity and create a process task for each
    // file.
    [0].getOutput().files.map(function (filename) {
      return swf.createActivityTask({
        name: "Process " + filename,
        activityType: "Process Input File",
        activityVersion: "buttered bread",
        input: { filename: filename }
      })
      .onFailed(function (errEvent) {
        // If the activity fails, send an email...
        return swf.createSeriesPipeline([
          swf.createActivityTask({
            name: "Announce failure",
            activityType: "Send Email",
            activityVersion: "1.2-final",
            input: {
              subject: "Processing failed for " + filename,
              body: "File " + filename + " failed: " + errEvent.getRawOuput(),
              to: "[email protected]"
            }
          }),
          // And fail the workflow
          // (Because we added an onFailed listener, the failure will not
          // trigger a workflow failure, so we explicitly add it.)
          swf.createFailWorkflowTask(errEvent.getOutput())
        ]);
      });
    });
    // Run all the file processing in parallel.
    return swf.createParallelPipeline(tasks);
  }),
  // Send an email when complete.
  swf.createActivityTask({
    name: "Announce completion",
    activityType: "Send Email",
    activityVersion: "1.2-final",
    input: {
      subject: "Processing Completed",
      body: "All Files Processed",
      to: "[email protected]"
    }
  })
]);

Listen for requests with a configured AWS connection:

const AWS = require('aws-sdk');
var swfClient = new AWS.SWF({
  region: region,
  accessKeyId: 'access key',
  secretAccessKey: 'secret access key'
});

swf.createDecider(workflowPipeline, swfClient, {
  domain: 'My Domain',
  identity: 'Process Incoming Files',
  taskList: {
    name: 'processIncomingFiles',
  },
})
.on('poll', function onPoll() {
  console.log(`Polling`);
})
.on('error', function onError(err) {
  console.error('Process Incoming Files Error: ' + err.message + '\n' + err.stack);
})
.start();

For full documentation on using the framework, please reference the documentation.

Support

Please create an issue if you believe you have found a bug or are having trouble. If you're able, please create a failing test for the bug you find so we can easily address it.

Contributions

Contributions are welcome. Please follow the guideines in .jshintrc and use JSBeautify before pushing. Also, make sure your code is tested with jasmine-node

License

Distributed under the MIT license

The MIT License (MIT)

Copyright (c) 2016 Matt Albrecht
Copyright (c) 2015 Dispatch Technologies Inc.

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