Configure S3-compatible access for Flask

Summary

Object storage client for a Flask app on Ample. Verified on Flask: bucket credentials delivered as encrypted S3_* environment variables and a validated PutObject/GetObject round-trip linked to a database row (upload=ok linked=ok). 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

• Verified compute: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request.
• Verified S3-compatible object storage: Buckets are S3-compatible with issued credentials.

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. 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.

   ample deploy . --name <app-name> --public --start "python3 app.py" --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
   

3. Verify. Fetch the live URL and /p/browser-file-uploads on the example; on failure read the build and runtime logs.

   ample logs <deployment_id> --kind build
   

Tested examples

• Flask pattern fixture: Verified object storage client on Flask.

Success checks

• app responds on its public URL (/ on the live URL)
• browser-file-uploads check from the example (/p/browser-file-uploads on the live URL)

Limitations

• Verified on the python-3.12 template at s-1vcpu-1gb; other sizes and Flask major versions are not verified.
• PutObject and GetObject with path-style addressing are verified; other S3 operations are not.

Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml).

• app server x1 s-1vcpu-1gb: 5.00 USD

Verification evidence

• canary_run on 2026-09-21T01:14:18Z at revision 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21): Flask pattern fixture deployed on Ample. (expires 2027-03-20T01:14:18Z)

Execution binding

MCP tool ample_deploy, binding state current, required scopes: servers:write, buckets:read.