lamby VS docker-rails-example

AWS Serverless Hero Ken Collins maintains a very popular Rails-Lambda package. After some discussion, he added the capability to track Proactive Initializations and came to a similar conclusion - in his case after a 3-day test using Ruby with a custom runtime, 80% of initializations were proactive:

This means the Monitoring with CloudWatch is just half the picture. But how much is your application potentially benefiting from proactive inits? Since Lamby v5.1.0, you can now find out easily using CloudWatch Metrics. To turn metrics on, enable the config like so:

After years of smashing Cloud & Rails together, I've come up with an idea. Better than an idea, a working specification! One where us Rails & Lambda enthusiasts can once again "console into" our "servers" and execute CLI tasks like migrations or interact via our beloved IRB friend, the Rails console. Today, I would like to present, the Lambda Console project. An open specification proposal for any AWS Lambda runtime to adopt.

> Does this mean you have a cron job just pinging the serverless function every 3 minutes? I'm curious how much this adds on to your costs. It means that the whole "don't pay for non-usage" thing is not quite true, but maybe it's still significantly cheaper than running an EC2 instance or whatnot. I'm curious about the cost calculation here.

Yes, specifically it kicks off a Lambda function that does a parallel GET to our website at a special endpoint that has a 100ms "wait" and basic DB call. This keeps the lambda process alive/in-memory.

To keep a function alive costs ~125ms (100ms wait + 25ms full func roundtrip). every 3 minutes. ~0.041% of 1x CPU time. Our website server costs are tiny and lower for Staging and UAT. Benefit - can scale to 1000x (AWS Limit) servers at the speed of your cold start time.

> Another thing I'm curious about, since you have a container-based deployment, did you compare with Fargate?

Yes we use Fargate for our core product which is built in Rails before containers could be deployed in Lambda. Rails works fine on Lambda[0] but the transition cost wasn't worth it for us. Fargate is great, but as you point out it is expensive if your application isn't a user heavy one like ours. To be highly available, we always have a minimum of 2 online but we're a b2b application so our night usage, 10pm-6am is zero. But I have 2 machines just sitting there. This is why i love Lambda >> Fargate.

Also, scalaing Fargate machines is slow if you get a traffic spike.

[0] https://github.com/rails-lambda/lamby

If you are curious to learn more about how Rails & Lambda work together, check out our Lamby project. The architecture of Lambda Containers works so well with Rails since our framework distills everything from HTTP, Jobs, Events, & WebSocket connections down to amazing CMD Docker contract. The architecture above at the proxy layer was easy to build and connect up to our single delegate function, Lamby.cmd. Shown below.

Today I am happy to announce that Lamby (Simple Rails & AWS Lambda Integration using Rack) now demonstrates just how easy it is to use multi-platform arm64 images on AWS Lambda. If this sounds interesting to you, jump right into our Quick Start guide and deploy a new Rails 7 on Ruby 3.2 Ubuntu image to see it for yourself.

(I have not actually used this myself). The folks over at CustomInk maintain Lamby, a project to run Rails in a quickly-bootable Lambda environment. Might be worth checking out, if you otherwise do enjoy working with Rails: https://lamby.custominktech.com

In any case you can try out https://github.com/customink/lamby which is a gem responsible to allow to run a ror app native on aws lambda.

I took a 13,000 line Rails 7.0 app and updated it to 7.1. I had to change 1 line of test configuration code to make everything work.

I would say that's a success for having an easy upgrade path. Now the fun part is going back to refactor some of the code to use the new features in 7.1.

If anyone is curious, I updated my Rails / Docker example app to use 7.1 too https://github.com/nickjj/docker-rails-example. Even though Rails 7.1 comes with a Dockerfile, there's still a lot of opinions you can add such as using Docker Compose to have a fully working out of the box experience that works in development and production -- complete with Postgres, Redis, Action Cable, Sidekiq and more.

Even though Rails 7.1 comes with a Dockerfile, there's still a lot of opinions you can add such as using Docker Compose to have a fully working out of the box experience that works in development and production.

If anyone is interested in that, I updated my example Rails app https://github.com/nickjj/docker-rails-example to use Rails 7.1 a few hours after 7.1 dropped.

If you're itching for Docker compatibility I maintain https://github.com/nickjj/docker-rails-example.

- https://github.com/nickjj/docker-rails-example

There's https://github.com/nickjj/docker-rails-example if you're looking for an end to end 1 command solution that works in dev and prod. It pulls together Puma, Sidekiq, Action Cable, Postgres, Redis, esbuild and Tailwind. It's all set up and ready to use Hotwire as well.

If anyone is looking for a more complete guide I put together this a while back: https://nickjanetakis.com/blog/a-guide-for-running-rails-in-...

The post also includes a ~1h hour ad-free YouTube video. It includes running Rails and also Sidekiq, Postgres, Redis, Action Cable and ties in esbuild and Tailwind too. It's all managed by Docker Compose.

The example app is open source at https://github.com/nickjj/docker-rails-example and it's optimized for both development and production. No strings attached.

If you're interested I've created https://github.com/nickjj/docker-rails-example with a base project using Docker Compose, Postgres, Redis, Sidekiq, Tailwind and esbuild.

I create an Up controller https://github.com/nickjj/docker-rails-example/blob/main/app/controllers/up_controller.rb and then have Uptime Robot https://uptimerobot.com/ hit it every few minutes.