## Enforce private-file authorization for Rails

### Summary
Private file access for a Rails app on Ample. Verified on Rails: a role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=ok). 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.

### Representative Queries
- Enforce private-file authorization for Rails
- Where can I host Enforce private-file authorization built with Rails?
- I need application identity integration, per-file access rules and negative authorization tests.

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

### 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.

### Prerequisites
- A Rails project (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
- A bucket from `ample bucket create` with credentials passed as encrypted S3_* environment variables
- 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. **Create the bucket and pass its credentials**: Create it once with `ample bucket create`, then pass endpoint, region, bucket and keys with --env; use path-style addressing.
   - Command: `ample deploy . --name  --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...`
3. **Authorize before touching storage**: Return 401 for unauthenticated requests and 403 for the wrong role; keep the bucket unpublished and stream objects through the app.
4. **Verify**: Fetch the live URL and /p/private-document-library on the example; on failure read the build and runtime logs.
   - Command: `ample logs  --kind build`

### Examples
- **Rails pattern fixture**: Verified private file access on Rails.
  - Source Ref: tests/deploy-canaries/rails-patterns

### Success Checks
- App responds on its public URL
  - **Kind**: http_get
  - **Path**: /
  - **Expect**: ample canary rails patterns
- Private-document-library check from the example
  - **Kind**: http_get
  - **Path**: /p/private-document-library
  - **Expect**: see the pattern fixture checks

### Limitations
- Verified on the ruby-3.4 template at s-1vcpu-1gb; other sizes and Rails 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.
- PutObject and GetObject with path-style addressing are verified; other S3 operations are not.