LES

"Let's Event Source Together"

• Validates the design of an event-based system specified in Event Markdown or Event Markup Language.
• Generates an API from Event Markdown or Event Markup
• LESTER Stack FAQ

Getting Started

Prerequisites

• NodeJS 8.11.1 LTS or better
• docker-compose

Installation

Instructions for Linux, Windows Mac & Docker

Hello World

Step 1:

cat <<EOT >> Eventstorming.emd
# Hello World
Say Hello World->
HelloWorld Said
EOT

Step 2:

les convert && les-node -b && cd api && npm install && docker-compose up -d

Or using Docker:

docker run -v $(pwd):/les les convert && docker run -v $(pwd):/les les-node -b && cd api && npm install && docker-compose up -d

(If you doing this in Linux and encounter "permission denied" errors, your USER or GROUP ID need to be specified. Say your USER ID is 1003, then add --user 1003 after each docker run in the above command.)

Step 3:

There is no step 3.

• Swagger/OpenAPI docs for the new API: http://localhost:3001/api-docs
• Source Code: ./api
• API URI: http://localhost:3001/api/v1
• Eventstore DB: http://localhost:2113 (username 'admin', password 'changeit')

What next ...

• Learn Event Storming: http://eventstorming.com

• Learn Event Markdown (EMD): https://webeventstorming.com

• EMD Examples: https://github.com/Adaptech/les/src/master/samples**

• EMD Cheat Sheet: https://github.com/Adaptech/letseventsource/raw/master/EMD-Cheatsheet-0.10.0-alpha-alpha.pdf

IDE Integrations & Tools

• Event Markdown vscode extension

Known UX Impacting Issues

The issues below have been known to mystify EMD users:

"DromedaryCase": myaggregateId GOOD, myAggregateId BAD

Adaptech#9

Sporadic Race condition when doing cd api && npm install && docker-compose up -d

API doesn't start because Eventstore isn't up yet. (Workaround: docker-compose restart api)

Adaptech#11

Need to have at least one read model parameter which is not an aggregate ID

Adaptech#10