Configure build and start for Flask

Summary

Configure build and start for a Flask app on Ample. Serve the WSGI app with a production server such as waitress from app.py reading PORT; pass --start "python3 app.py". Ample detects the runtime, installs dependencies, runs the build when present and starts the app on the python-3.12 template behind a public HTTPS URL.

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.)

Prerequisites

• A requirements.txt (or pyproject) and a start command that reads PORT and binds 0.0.0.0
• An Ample account token with servers:write

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. Make the start command bind correctly. Serve the WSGI app with a production server such as waitress from app.py reading PORT; pass --start "python3 app.py".

2. Deploy. Run the existing synchronous deploy once from the project directory and read the result. Exit 0 is live, 1 is failed, 2 is blocked on a required preflight action. Re-running with no change is a content-addressed no-op.

   ample deploy . --name <app-name> --public --format json --start "python3 run.py"
   

3. Verify. Fetch the live URL and run the success checks below. On failure read the build log, then the runtime log, fix the cause and deploy again; do not blind-retry.

   ample logs <deployment_id> --kind build
   

Tested examples

• flask-basic canary (tests/deploy-canaries/flask-basic): Flask app served by waitress.

Success checks

• page or root route responds (/ on the live URL, expect ample canary flask basic)

Limitations

• Verified on the node-22 template at s-1vcpu-1gb; other templates and sizes are not verified by this recipe.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
• The Flask development server was not used; waitress was tested.

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

Verification evidence

• canary_run on 2026-09-20T00:22:15Z at revision 1764076-tls-account-903d345: Flask app served by waitress on python-3.12 and rendered the expected response. (expires 2027-03-19T00:22:15Z)

Last verified: 2026-09-20T00:22:15Z

Execution binding

MCP tool ample_deploy (registry mcp:ample_deploy), schema hash 876465fce906da0c observed 2026-09-20T01:55:48.667900+00:00 at revision 199ff1dfd526, binding state current, required scopes: servers:write.