Deliver public assets through CDN for FastAPI

Summary

Cdn assets for a FastAPI app on Ample. Verified on FastAPI: 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 uvicorn from run.py reading PORT on the python-3.12 template.

Infrastructure requirements

• Compute: 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: 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 FastAPI project (pip install into .ample/python from requirements.txt, then uvicorn from run.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 run.py

Steps

1. Build and start. pip install into .ample/python from requirements.txt, then uvicorn from run.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

• FastAPI pattern fixture (tests/deploy-canaries/fastapi-patterns): Verified CDN assets on FastAPI.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary fastapi 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 FastAPI 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): FastAPI pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then uvicorn from run.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.