# Connect Postgres for Axum

## Summary

Database connection for a 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: cargo build --release 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.

## Infrastructure requirements

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- [Postgres](/content/discover/primitive/postgres/index.html): verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)

## Prerequisites

- A Axum project (cargo build --release 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)
- A PostgreSQL driver reading DATABASE_URL at runtime
- An Ample account token with servers:write, databases:read

## Exact tested configuration

- template: `ubuntu-24.04`
- runtime: `rust`
- size: `s-1vcpu-2gb`
- build: `cargo build --release`
- start: `./$(ls target/release/*.d | grep -v '/lib' | head -n 1 | sed 's/\.d$//')`

## Steps

1. **Build and start.** cargo build --release 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; 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.
   
   ```
   ample logs <deployment_id> --kind build
   ```

## Tested examples

- **Axum pattern fixture** (tests/deploy-canaries/axum-patterns): Verified database connection on Axum.

## Success checks

- app responds on its public URL (`/` on the live URL, expect ample canary axum patterns)
- relational-records check from the example (`/p/relational-records` on the live URL, expect see the pattern fixture checks)

## Limitations

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

## Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD
- managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Verification evidence

- canary_run on 2026-09-21T02:46:37Z at revision `1d28ae0-dirty (CLI 0.1.21)`: Axum pattern fixture deployed on Ample (cargo build --release 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); for this guide: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). (expires 2027-03-20T02:46:37Z)

Last verified: 2026-09-21T02:46:37Z

## Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-21T03:19:59.461917+00:00 at revision `49962bcade4f`, binding state `current`, required scopes: servers:write, databases:read.