Serverless Integration Patterns

This project implements some of the examples from Enterprise Integration Patterns using AWS Lambda and serverless framework.

About

Enterprise Integration Patterns is an awesome book about how to make software systems talk to each other. AWS Lambda is an interesting new way to run code without managing conventional servers. Serverless is a way to use Lambda without tearing your hair out.

Chapter 2 of EIP defines four common integration styles: Flat Files, Shared Database, Remote Procedure Invocation, and Messaging. Lambda's features map to each of these styles, and many of the messaging patterns in the rest of the book. Triggers for Lambda functions include:

• S3 writes (flat files)
• HTTP requests through API Gateway (RPC/messaging)
• DynamoDB triggers (shared database/messaging)
• SNS notifications (messaging)
• Kinesis streams (messaging)

It's a great toolkit for experimenting with the patterns in EIP.

Getting Started

To deploy the examples in this repo you'll need:

• Python 2.7.x
• pip, the Python package manager
• Node v4.x.x or higher
• Serverless framework
• An AWS account

Once you have Node and Python, install serverless with:

$ npm install -g serverless

Serverless has great docs on getting started. Give them a read and follow the instructions.

You'll also need to make sure AWS credentials are configured. Follow the serverless docs here.

To install Python dependencies, run:

$ pip install -r requirements.txt

Deploying the examples

Every directory in this repo containing a serverless.yml file is a deployable serverless application. To spin up an example, cd into one and run:

$ serverless deploy

This will spin up all the Lambdas and necessary AWS infrastructure associated with the example:

$ serverless deploy
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
.....
Serverless: Stack create finished...
Serverless: Packaging service...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading service .zip file to S3 (9.63 KB)...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
.................................................
Serverless: Stack update finished...

At the end of a successful deploy, it will usually print out a few API Gateway endpoints, which are usually entrypoints to the example code:

Service Information
service: message-channel
stage: dev
region: us-east-1
api keys:
  None
endpoints:
  POST - https://gb6e8kd2r0.execute-api.us-east-1.amazonaws.com/dev/message-channel/send
functions:
  send-message: message-channel-dev-send-message
  receive-message: message-channel-dev-receive-message

For details on what these do, see the README.md files inside each example directory.

Make sure you remove all the provisioned resources when you're done. To do so, run:

$ serverless remove

Tests

From the repo root, run:

$ nosetests