## Enforce private-file authorization for Sinatra

### Summary
Private file access for a Sinatra app on Ample. Verified on Sinatra: 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 `rackup` (config.ru) reading PORT on the ruby-3.4 template.

### Representative Queries
- Enforce private-file authorization for Sinatra
- Where can I host Enforce private-file authorization built with Sinatra?
- 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
1. **Compute**  
   - Status: verified  
   - Summary: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. **Postgres**  
   - Status: verified  
   - Summary: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
3. **S3-compatible object storage**  
   - Status: verified  
   - Summary: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

### 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.
- 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.

### 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 rackup -o 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 `rackup` (config.ru) reading PORT on the ruby-3.4 template; 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
- **Sinatra pattern fixture**: Verified private file access on Sinatra.  
   Source Reference: tests/deploy-canaries/sinatra-patterns

### Success Checks
1. **App responds on its public URL**  
   - Kind: http_get  
   - Path: `/`  
   - Expect: ample canary sinatra patterns
2. **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 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.
- PutObject and GetObject with path-style addressing are verified; other S3 operations are not.

### 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: size s-1vcpu-1gb, quantity 1.0, monthly amount 5.0
   - Managed PostgreSQL database: size s-1vcpu-1gb, quantity 1.0, monthly amount 5.0  
- **Note**: Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

### Evidence Summary
- **Kind**: canary_run  
  **Summary**: 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 role-to-document access model with negative tests (401, 403) and an authorized private-bucket round-trip (private=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/private-document-library'], template: ruby-3.4

### Last Verified At
2026-09-20T23:45:31Z

### Unknowns
- Region availability is unknown until a verified region fact is recorded.
- Compliance attestations are unknown; none are claimed.

### Formats
- HTML: [View](/content/guides/sinatra/private-file-access/index.html)  
- Markdown: [View](/content/guides/sinatra/private-file-access.md)  
- JSON: [View](https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Asinatra%3Aprivate-file-access)

### Next Actions
1. **Browse the catalog index**  
   Method: GET  
   Relative Path: `/v1/catalog`  
   Requires Authentication: false
2. **Search published recipes by intent, stack and constraints**  
   Method: POST  
   Relative Path: `/v1/catalog/search`  
   Body: {"limit":5,"query":"Enforce private-file authorization for Sinatra"}  
   Requires Authentication: false  
3. **Prepare a side-effect-free deployment plan for an authorized project**  
   Method: POST  
   Relative Path: `/v1/catalog/plan`  
   Body: {"inputs":{},"projectId":"","recipeId":"page:guides:sinatra:private-file-access","recipeRevision":"r1"}  
   Requires Authentication: true  
4. **Read the existing agent authentication setup**  
   Method: GET  
   Relative Path: `/mcp/setup`  
   Requires Authentication: false
5. **Browse Sinatra**  
   Method: GET  
   Relative Path: `/v1/catalog/nodes/stack%3Aframework-sinatra`  
   Requires Authentication: false
6. **Browse Connect app to storage**  
   Method: GET  
   Relative Path: `/v1/catalog/nodes/intent%3Aconnect-app-to-storage`  
   Requires Authentication: false
7. **Browse Private document library**  
   Method: GET  
   Relative Path: `/v1/catalog/nodes/pattern%3Aprivate-document-library`  
   Requires Authentication: false