DEPRECATED

There are way better tools out there for running workflows. Examples:

• Apache Airflow
• AWS Step Functions

emjen

Description

Environment Manager Job ENgine is a library that provides durable workflow support using DynamoDB and SQS and comprises orchestrator and worker modules.

Installation

1. Create the AWS resources the library will use at runtime.
2. Install the library.

Usage

1. Start a worker.

   let AWS = require('aws-sdk);
   let emjen = require('emjen');
   let commands = {
       'echo/v1': ({ Args: { Message } }, { sendToReplyQueue }) =>     sendToReplyQueue({ Result: Message, Status: completed, Type: TaskCompleted }),
   };
   let inboundQueue = 'https://sqs.eu-west-1.amazonaws.com/123456789012/worker-queue'
   // Start the worker
   let worker = emjen.worker({ commands, inboundQueue, queueClient: emjen.sqsQueueClient(new AWS.SQS()) });
   // Stop the worker
   let stopped = worker.stop();
   // Do something after the worker has stopped
   stopped.then(() => ...)
   

2. Start an orchestrator.

   let emjen = require('emjen');
   let inboundQueue = 'https://sqs.eu-west-1.amazonaws.com/123456789012/orchestrator-queue'
   let stateTable = 'emjen-jobs'
   let workQueue = 'https://sqs.eu-west-1.amazonaws.com/123456789012/worker-queue'
   // Start the orchestrator
   let orchestrator = emjen.orchestrator({
       inboundQueue,
       queueClient: emjen.sqsQueueClient(new AWS.SQS())
       stateTable,
       tableClient: emjen.dynamoTableClient(new AWS.DynamoDB.DocumentClient())
       workQueue
   });
   // Stop the orchestrator
   let stopped = orchestrator.stop();
   // Do something after the orchestrator has stopped
   stopped.then(() => ...)
   

3. Submit a job

   let startTime = Date.now();
   let job = {
       Type: 'NewJob',
       Job: {
           JobId: '1',
           Status: 'active',
           Tasks: {
               EchoHello1: {
                   Params: { Message: 'Hello' },
                   Command: 'echo/v1',
                   LastModified: startTime,
                   Seq: 0,
                   Status: 'pending',
                   TTL: 10000,
               },
               EchoWorld2: {
                   Params: { Message: { $ref: '/EchoHello1/Result' } },
                   Command: 'echo/v1',
                   LastModified: startTime,
                   Seq: 0,
                   Status: 'pending',
                   TTL: 20000,
               },
           },
       },
   };
   orchestrator.submit(job).then(() => console.log('job submitted'));