fly-rails

Purpose

Add Fly.io support to Rails.

Usage

For usage instructions, see the following guides:

• Machine API
• Lite FS
• Terraform

Generator options

• --name name of the application. If a name is not provided, one will be generated for you.
• --org the organization to operate on. Defaults to personal.
• --region region to launch the application in. Accepts multiple values, and can be specified multiple times.
• --nomad generates a nomad application instead of a machines application.
• --litefs adds support for replicated sqlite3 databases via litefs. Only works on nomad machines currently.
• --passenger run your Rails application with nginx and Phusion Passenger.
• --serverless configures your application to exit after 5 minutes of inactivity. Machines will automatically restart when next accessed. Only works with passenger currently.

Automatically detected features

• ruby: the deployed application will use the same version of ruby and bundler as your development environment.
• node: if the use of node is detected, node, yarn, and your npm packages will be installed.
• sqlite3: if the production database is sqlite3 a volume will be allocated and the database will be put there.
• postgres: if the production database is postgres a postgres machine will be allocated
• redis: if redis is used for action cable, caching, or sidekiq your redis database will be added to this application. If you don't currently have a redis database, one will be allocated. If redis is used for caching, eviction will be turned on.
• sidekiq: if sidekiq is used it will be launched along side of your rails application.

Key files

• Entrypoints: lib/tasks/fly.rake, lib/generators/app_generator.rb, lib/generators/terraform_generator.rb contain the deploy task, fly:app generator and fly:terraform generator respectively.
• lib/fly.io-rails/actions.rb contains Thor actions used by the rake task and generators. Does some funky stuff to allow Thor actions to be called from Rake.
• lib/fly.io-rails/machines.rb wraps Fly.io's machine API as a Ruby module.
• lib/generators/templates contains erb templates for all of the files produced primarily by the generator, but also by the deploy task.
• Rakefile used to build gems. Includes native binaries for each supported platform.

Build instructions

rake package

This will involve downloading binaries from github and building gems for every supported platform as well as an additional gem that doesn't include a binary.

To download new binaries, run rake clobber then rake package agein.

Debugging instructions

This gem provides a Railtie, with rake tasks and a generator that uses Thor and templates. Being in Ruby, there is no "compile" step. That coupled with Bundler "local overrides" makes testing a breeze. And Rails 7 applications without node dependencies are quick to create.

A script like the following will destroy previous fly applications, create a new rails app, add and then override this gem, and finally copy in any files that would need to be manually edited.

if [ -e welcome/fly.toml ]; then
  app=$(awk -e '/^app\s+=/ { print $3 }' welcome/fly.toml | sed 's/"//g')
  fly apps destroy -y $app
fi
rm -rf welcome
rails new welcome
cd welcome
bundle config disable_local_branch_check true
bundle config set --local local.fly.io-rails /Users/rubys/git/fly.io-rails
bundle add fly.io-rails --git https://github.com/rubys/fly.io-rails.git
cp ../routes.rb config
# bin/rails generate terraform
# fly secrets set FLY_API_TOKEN=$(fly auth token)
# bin/rails generate controller job start complete status
# bin/rails generate job machine
# cp ../job_controller.rb app/controllers/
# cp ../machine_job.rb app/jobs/

Once created, I rerun using:

cd ..; sh redo-welcome; cd welcome; 

Generally after the finaly semicolon, I have commands like bin/rails generate fly:app --litefs; fly deploy. Rerunning after I make a change is a matter of pushing the up arrow until I find this command and then pressing enter.