Connect Postgres for Flask

Summary

Connect a Flask app to PostgreSQL on Ample. Read DATABASE_URL at runtime with psycopg: when you supply one with --env it is delivered encrypted and takes precedence; when you supply none and the app needs PostgreSQL, Ample auto-provisions a managed PostgreSQL 16 database and injects its connection string.

Prerequisites

• psycopg reading the DATABASE_URL environment variable at runtime
• Either a production DATABASE_URL to pass with --env, or nothing (auto-provision)
• An Ample account token with servers:write and databases:read

Workflow Steps

1. Read the URL at runtime
   Open connections from the DATABASE_URL environment variable inside the app; never commit credentials and never connect at build time.
2. Choose the source of the database
   Pass --env DATABASE_URL=... for an existing database, or omit it to let Ample provision a managed one on first deploy and reuse it on redeploys.
   Command: ample deploy . --name --public --start "python3 run.py"
3. Test the connection through the app
   Expose a route (/items) that runs a trivial query and returns postgres=ok.
4. 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.
   Command: ample logs --kind build

Examples

• Flask + PostgreSQL canary: Auto-provisioned managed database with a real query.
  Source Ref: tests/deploy-canaries/flask-postgres-app

Success Checks

• Database route reports a live connection
  Kind: http_get
  Path: /items
  Expect: postgres=ok

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.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.
• Apps and their managed databases are placed together; cross-node shared databases are unsupported.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.00
• Note: Apps and managed databases auto-pause when idle; the estimate is the always-on monthly price of the tested sizes. Plan quotas and budgets apply.

Components

1. App server
   • Size: s-1vcpu-1gb
   • Quantity: 1.0
   • Monthly Amount: 5.0
2. Managed PostgreSQL database
   • Size: s-1vcpu-1gb
   • Quantity: 1.0
   • Monthly Amount: 5.0

Evidence Summary

• Kind: canary_run
  Summary: Flask app (waitress) using psycopg with an auto-provisioned managed PostgreSQL database: /items reported postgres=ok and /config confirmed the encrypted secret.
  Observed At: 2026-09-20T01:42:25Z

• Kind: canary_run
  Summary: Node app needing PostgreSQL with no DATABASE_URL: a managed database was auto-provisioned and /db reported postgres=ok.
  Observed At: 2026-09-19T23:55:33Z

Next Actions

• Browse the catalog index
  Action ID: browse-catalog
  Operation ID: catalog_index
• Search published recipes by intent, stack and constraints
  Action ID: search-recipes
  Operation ID: search_recipes
• Prepare a side-effect-free deployment plan for an authorized project
  Action ID: plan:page:guides:flask:database-connection
  Operation ID: plan_deployment