Host digital downloads with Rails: public product media

Summary

Deploy a digital downloads built with Rails on Ample using the public media library 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, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables, and a published bucket serves public assets from the CDN host. Verified on Rails: an object written to a published bucket with an immutable Cache-Control header, a mapping row, and the CDN URL serving it publicly. Not separately tested: your media processing, object layout and cache policy; treat the digital downloads-specific behavior as your application code.

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.)
• S3-compatible object storage: verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)
• CDN: verified (The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.)

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)
• A bucket from ample bucket create with its credentials passed as encrypted S3_* environment variables and a second, published bucket for public assets (CDN_*)
• An Ample account token with servers:write, databases:read, buckets:read

Exact tested configuration

• template: ruby-3.4
• runtime: ruby
• size: s-1vcpu-1gb
• install: bundle config set --local path vendor/bundle && bundle config set --local without 'development test' && bundle install
• start: bundle exec rails server -b 0.0.0.0 -p $PORT

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 public media library: an object written to a published bucket with an immutable Cache-Control header, a mapping row, and the CDN URL serving it publicly. Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. Wire object storage. Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket. Publish only the bucket that serves public assets and reference its CDN URL.
4. 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 <app-name> --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... --env CDN_PUBLIC_URL=...

5. Verify. Fetch the live URL and the pattern self-test route(s) (/p/public-media-library) from the example; then run your own checks. On failure read ample logs <deployment_id> --kind build then --kind runtime.

   ample logs <deployment_id> --kind build

Tested examples

• Rails pattern fixture (tests/deploy-canaries/rails-patterns): Multi-pattern Rails app whose public media library module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary rails patterns)
• public-media-library self-test (/p/public-media-library on the live URL, expect a CDN URL whose content is served publicly)

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 digital downloads itself (your media processing, object layout and cache policy) is application code and was not separately tested; the pattern checks are what was verified.