# Connect Postgres for Axum

## Summary
Database connection for an Axum app on Ample. Verified on Axum: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). Build and start using the following command:

```bash
cargo build --release
```

This should be run in the Rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL.

## Prerequisites
- A Axum project (use `cargo build --release` in the rust builder image)
- A PostgreSQL driver reading DATABASE_URL at runtime
- An Ample account token with `servers:write`, `databases:read` permissions

## Resource Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request.
- **Postgres**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

## Workload
### Steps to Connect Postgres
1. **Build and start**: 
   ```bash
   cargo build --release
   ```
   The server must bind 0.0.0.0 on PORT.

2. **Read DATABASE_URL at runtime**: 
   Open connections from the environment inside handlers or a pool; omit DATABASE_URL to auto-provision a managed database or pass `--env DATABASE_URL=...` for an existing one.

3. **Verify**: 
   Fetch the live URL and `/p/relational-records` on the example; on failure read the build and runtime logs.
   ```bash
   ample logs --kind build
   ```

## Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-2gb; other sizes and Axum major versions are not verified.
- Region and compliance attestations and request-duration limits are unknown.
- Managed PostgreSQL 16 only; extensions, connection limits, and backup or restore procedures are not verified.

## Cost Estimate
- **Monthly Amount**: $10.00
- **Components**:
  - App server: s-1vcpu-1gb, 1.0, $5.00
  - Managed PostgreSQL database: s-1vcpu-1gb, 1.0, $5.00

**Note**: Always-on monthly price of the tested sizes; apps auto-pause when idle.

## Success Checks
- App responds on its public URL
- Relational records check from the example

## Evidence Summary
- Axum pattern fixture deployed on Ample, with a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time.

## Next Actions
- **Browse the catalog index**: [API Catalog](https://api.ample.computer/v1/catalog)
- **Search published recipes**: [Search Recipes](https://api.ample.computer/v1/catalog/search)