# Connect Postgres for Gin

## Summary

Database connection for a Gin app on Ample. Verified on Gin: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). Build and start: CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build).

## Infrastructure requirements

- Verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- 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 Gin project (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build))
- 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: `go`
- size: `s-1vcpu-1gb`
- build: `CGO_ENABLED=0 go build -o app ./...`
- start: `./app`

## Steps

1. **Build and start.** CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build); 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

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

## Success checks

- app responds on its public URL (`/` on the live URL, expect ample canary gin 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-1gb; other sizes and Gin 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 2026-09-21T01:15:54Z at revision `50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)`: Gin pattern fixture deployed on Ample (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build)); for this guide: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). (expires 2027-03-20T01:15:54Z)

Last verified: 2026-09-21T01:15:54Z