### Deliver public assets through CDN for Sinatra

**Summary:**  Cdn assets for a Sinatra app on Ample. Verified on Sinatra: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. 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
- Deliver public assets through CDN for Sinatra
- Where can I host Deliver public assets through CDN built with Sinatra?
- I need a public-origin configuration, versioned asset build and observable cache behavior.

#### Resource Requirements
- **Compute (primitive:compute)**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **CDN (primitive: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
1. 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).
2. A bucket from `ample bucket create` with credentials passed as encrypted S3_* environment variables.
3. An Ample account token with `servers:write`, `buckets: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. **Publish a bucket for public assets**: Publish only the asset bucket; upload versioned keys with an immutable Cache-Control header and build URLs from its public URL. Command: `ample bucket publish`
3. **Verify**: Fetch the live URL and `/p/versioned-static-assets` on the example; on failure read the build and runtime logs. Command: `ample logs --kind build`

#### Examples
- **Sinatra pattern fixture**: Verified CDN assets on Sinatra.

#### Success Checks
- App responds on its public URL
- Versioned-static-assets 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.
- The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified.

#### Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: 5.0  
- **Basis**: Size prices from `pricing.toml` at build revision `1ac5595375130d45290090e82ed0f554ccd45405-dirty`  
- **Components**:  
  - App server, 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.

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

#### Formats
- **HTML**: [https://ample.computer/guides/sinatra/cdn-assets](/content/guides/sinatra/cdn-assets/index.html)  
- **Markdown**: [https://ample.computer/guides/sinatra/cdn-assets.md](/content/guides/sinatra/cdn-assets.md)  
- **JSON**: [https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Asinatra%3Acdn-assets](https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Asinatra%3Acdn-assets)

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