Ruby

Primcloud deploys Ruby apps (Rails, Sinatra, Rack, plain Ruby workers) from a repo that carries a Gemfile and Gemfile.lock. Detection triggers the moment Primcloud finds Gemfile.lock at the repo root. Your Ruby version comes from the lockfile's RUBY VERSION entry and your Bundler version from its BUNDLED WITH entry, so the runtime you build against is the one your lockfile already names.

Every build runs bundle install. Rails apps get a shortcut: if your lockfile carries the railties gem, Primcloud generates a default web process that runs bin/rails server, so a stock Rails app deploys with no Procfile at all. A Rack app with a config.ru gets a bundle exec rackup default the same way. Ship your own Procfile and it overrides both.

What's in this section#

• Getting started with Ruby: deploy a minimal Rack app end-to-end.
• Ruby on Primcloud: detection, bundle install, rake assets:precompile, cache layers, and default process types.
• Runtime versions: supported Ruby versions, pinning via Gemfile and Gemfile.lock, and the upgrade path.
• Package managers: Bundler behavior, private gem sources, and lockfile enforcement.
• Customizing the build: rake hooks, custom install steps, native gem dependencies, and Debian packages via project.toml.
• Troubleshooting Ruby: common build and runtime errors with fixes.
• Deploying Rails: Rails-specific setup, RAILS_MASTER_KEY, migrations, and asset compilation.