page:recipes:form collection:rails:relational workflow

Host form collection with Rails: relational workflow state

Summary

Deploy a form collection 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 form collection-specific behavior as your application code.

Representative Queries

• Host form collection with Rails: relational workflow state
• Where can I host Form collection built with Rails?
• I need a domain record schema, validation rules and concurrency behavior.

Resource Requirements

• primitive:compute
• primitive:postgres

Infrastructure Requirements

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

Prerequisites

• 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)
• A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
• An Ample account token with servers:write, databases:read

Tested Configuration

• Template: ruby-3.4
• Runtime: ruby
• Size: s-1vcpu-1gb
• Install Command: bundle config set --local path vendor/bundle && bundle config set --local without 'development test' && bundle install
• Start Command: bundle exec rails server -b 0.0.0.0 -p $PORT

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). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
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  --public  
   

4. Verify
   Fetch the live URL and the pattern self-test route(s) (/p/transactional-workflows) from the example; then run your own checks. On failure read ample logs --kind build then --kind runtime.

   ample logs  --kind build  
   

Success Checks

• App responds on its public URL
  • Kind: http_get
  • Path: /
  • Expected: ample canary rails patterns
• Transactional-workflows self-test
  • Kind: http_get
  • Path: /p/transactional-workflows
  • Expected: tx=ok history=2 conflict=rejected

Limitations

• 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.
• The form collection itself (your domain records, validation rules and concurrency policy) is application code and was not separately tested; the pattern checks are what was verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Authoritative: true
• Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
• Components:
  • App server: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: 5.0
  • Managed PostgreSQL database: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: 5.0
• Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

Evidence Summary

• Canary Run:
  • Summary: Rails pattern fixture deployed on Ample (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); checks passed for transactional-workflows and configuration-secrets.
  • Observed At: 2026-09-20T21:55:28Z
  • Implementation Revision: 4f7cb9813c1f-dirty (CLI 4f7cb98)
  • Expires At: 2027-03-19T21:55:28Z
• Canary Run:
  • Summary: The same Rails app deployed with a --release-command migration; the marker it created was readable after activation.
  • Observed At: 2026-09-20T21:55:28Z
  • Implementation Revision: 4f7cb9813c1f-dirty (CLI 4f7cb98)
  • Expires At: 2027-03-19T21:55:28Z

Next Actions

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