# 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.

## Representative Queries
- Host digital downloads with Rails: public product media
- Where can I host Digital downloads built with Rails?
- I need product-to-object mappings and a tested public media delivery path.

## Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:s3-compatible-object-storage
- primitive:cdn

## Infrastructure Requirements
### Compute
Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

### 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.

### S3-compatible object storage
Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

### CDN
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

## 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 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  --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  --kind build` then `--kind runtime`.  
   `ample logs  --kind build`

## Examples
### Rails pattern fixture
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 (kind: http_get, path: /, expect: ample canary rails patterns)
- public-media-library self-test (kind: http_get, path: /p/public-media-library, 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.
- 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.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.
- The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified (the fixture sets Cache-Control on upload and versions keys).

## Cost Estimate
- Currency: USD  
- Monthly Amount: 10.0
- Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty

### Components
- app server (s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0)
- managed PostgreSQL database (s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 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.