Example Rails app

[Envek]

I made a dead simple Rails application that demonstrates how to use NATS Ruby client withing Rails application using new additions.

However, I'm incredibly bad at coming up with arbitrary examples, so for now idea is dumb: there is a web form which upon submit doesn't create a database record directly (as most typical applications do) but instead publishes a message into NATS and let different process to receive it and create database record instead.

Share your ideas, so I can add more interesting stuff.

Also for now it is not very pleasantly looking one (but this also can be fixed):

README.md

Files of interest:

• config/initializers/nats.rb — initialization of the NATS client early using lazy connection.
• app/controllers/test_controller.rb — example of the controller.
• bin/nats-listener — example of the separate standalone process.

Main client features shown in the example:

• Thread-safety and fork handling: it is totally fine to use “global” NATS client instance without any connection pooling.
• Rails development mode code reloading and resource handling: no more server restarts on changes and leaked database connections.

A (somewhat artificial) distributed workflow:

• User fills the form and submits it.
• The form is broadcasted via NATS using “global” NATS client instantiated in the web application server “master” process, but usable in worker processes.
• Special long running process (listener) subscribes to the broadcasted messages and saves them to the database.
• User will eventually see saved messages on the page with the form.

Installation

This app has a Docker-first configuration based one the Ruby on Whales post.

You need:

• Docker installed. For MacOS just use official app.

• Dip installed.

Run the following command to build images and provision the application:

dip provision

Running

You can start Rails server along with AnyCable by running:

dip up web listener

Then go to http://localhost:3000/ and see the application in action.