page:recipes:event registration:rails:relational workflow

Host Event Registration with Rails: Relational Workflow State

Deploy an event registration built with Rails on Ample using the transactional workflows pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Rails: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the event registration-specific behavior as your application code.

Representative Queries

Resource Requirements

Infrastructure Requirements

  1. Compute: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
  2. Postgres: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

Framework

Prerequisites

  1. A Rails project that builds and starts with the documented commands (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rails server reading PORT on the ruby-3.4 template with RAILS_ENV=production).
  2. A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
  3. An Ample account token with servers:write, databases:read.

Workflow Steps

  1. Build and Start: bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rails server reading PORT on the ruby-3.4 template with RAILS_ENV=production. The server must bind 0.0.0.0 on PORT.
  2. Implement the Pattern on PostgreSQL: The fixture's module implements transactional workflows: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected).
  3. Deploy: Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op. ample deploy . --name <your_name> --public
  4. Verify: Fetch the live URL and the pattern self-test route(s) (/p/transactional-workflows) from the example; run your own checks. On failure, read ample logs --kind build then --kind runtime. ample logs --kind build

Success Checks

  1. App responds on its public URL: HTTP GET / should return ample canary rails patterns.
  2. Transactional workflows self-test: HTTP GET /p/transactional-workflows should return tx=ok history=2 conflict=rejected.

Limitations

  1. Verified on the ruby-3.4 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Rails major versions are not verified.
  2. The event registration itself (your domain records, validation rules, and concurrency policy) is application code and was not separately tested; the pattern checks are what was verified.
  3. Unknowns about region, compliance attestations, and request-duration limits.
  4. Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
  5. Managed PostgreSQL 16 only; extensions, connection limits, and backup or restore procedures are not verified; apps and their databases are placed together.

Cost Estimate