page:guides:sinatra:schema changes

Apply Database Schema Changes for Sinatra

Summary

Schema changes for a Sinatra app on Ample. Verified on Sinatra: a --release-command migration ran before activation and its marker was readable by the live app (migrated=release-ok). Build and start: bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rackup (config.ru) reading PORT on the ruby-3.4 template.

Prerequisites

• A Sinatra project (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rackup (config.ru) reading PORT on the ruby-3.4 template)
• A PostgreSQL driver reading DATABASE_URL at runtime
• 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 rackup (config.ru) reading PORT on the ruby-3.4 template; the server must bind 0.0.0.0 on PORT.

2. Run migrations as the release command
   Ample runs the command before activation and fails the release if it exits non-zero; keep migrations idempotent.

   ample deploy . --name  --public --release-command "python3 migrate.py"
   

3. Verify
   Fetch the live URL and /p/migrated on the example; on failure read the build and runtime logs.

   ample logs  --kind build
   

Success Checks

• App responds on its public URL.
• Migrated check from the example.

Limitations

• Verified on the ruby-3.4 template at s-1vcpu-1gb; other sizes and Sinatra major versions are not verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Note: Always-on monthly price of the tested sizes; apps auto-pause when idle.

Examples

• Sinatra pattern fixture
  Verified schema changes on Sinatra.
  Source Reference: tests/deploy-canaries/sinatra-patterns

Evidence Summary

• Canary Run
  Sinatra pattern fixture deployed on Ample (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via rackup (config.ru) reading PORT on the ruby-3.4 template); for this guide: a --release-command migration ran before activation and its marker was readable by the live app (migrated=release-ok).
  • Observed at: 2026-09-20T23:45:31Z
  • Implementation Revision: 4d1511e574302f3904b75088bd4048a0975218b3-dirty (CLI 0.1.21)
  • Expires At: 2027-03-19T23:45:31Z
  • Scope:
    • Checks: /p/migrated
    • Template: ruby-3.4

Next Actions

• Browse the catalog index
• Search published recipes by intent, stack and constraints
• Prepare a side-effect-free deployment plan for an authorized project
• Read the existing agent authentication setup
• Browse Sinatra
• Browse Configure deployment
• Browse Transactional workflows