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.
1. 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(() => ...)
`
1. 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(() => ...)
`
1. 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'));
``