# Connect Postgres for FastAPI

## Summary
Connect a FastAPI 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.

## Representative Queries
- Connect Postgres for FastAPI  
- Where can I host Connect Postgres built with FastAPI?  
- I need driver setup, connection settings, secret handling and a real connection test.

## 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`

## 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**: 10.0  
- **Basis**: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty

### Components
- **App server**  
  - **Size**: s-1vcpu-1gb  
  - **Quantity**: 1.0  
  - **Monthly Amount**: 5.0
- **Managed PostgreSQL database**  
  - **Size**: s-1vcpu-1gb  
  - **Quantity**: 1.0  
  - **Monthly Amount**: 5.0

**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.

## Evidence Summary
- **Kind**: canary_run  
  **Summary**: FastAPI REST API using psycopg with no DATABASE_URL supplied: Ample auto-provisioned a managed PostgreSQL 16 database and /items reported postgres=ok after a real insert and count.  
  **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

## Formats
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