# Deliver public assets through CDN for Flask

## Summary

Cdn assets for a Flask app on Ample. Verified on Flask: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. Build and start: pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template.

## Infrastructure requirements

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- [CDN](/content/discover/primitive/cdn/index.html): 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 Flask project (pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template)
- A bucket from `ample bucket create` with credentials passed as encrypted S3_* environment variables
- An Ample account token with servers:write, buckets:read

## Exact tested configuration

- template: `python-3.12`
- runtime: `python`
- size: `s-1vcpu-1gb`
- install: `python3 -m pip install --target .ample/python -r requirements.txt`
- start: `PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 app.py`

## Steps

1. **Build and start.** pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 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.

```
   ample bucket publish <bucket-name>
   ```
3. **Verify.** Fetch the live URL and /p/versioned-static-assets on the example; on failure read the build and runtime logs.

```
   ample logs <deployment_id> --kind build
   ```

## Tested examples

- **Flask pattern fixture** (tests/deploy-canaries/flask-patterns): Verified CDN assets on Flask.

## Success checks

- app responds on its public URL (`/` on the live URL, expect ample canary flask patterns)
- versioned-static-assets check from the example (`/p/versioned-static-assets` on the live URL, expect see the pattern fixture checks)

## Limitations

- Verified on the python-3.12 template at s-1vcpu-1gb; other sizes and Flask 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

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD

Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Verification evidence

- canary_run on 2026-09-21T01:14:18Z at revision `50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)`: Flask pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template); for this guide: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. (expires 2027-03-20T01:14:18Z)

Last verified: 2026-09-21T01:14:18Z

## Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-21T03:19:59.461917+00:00 at revision `49962bcade4f`, binding state `current`, required scopes: servers:write, buckets:read.