# Connect Postgres for Spring Boot

## Summary

Database connection for a Spring Boot app on Ample. Verified on Spring Boot: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). Build and start: `./mvnw -q -DskipTests package` (or the Gradle wrapper) producing one application jar, then `java -jar` on the jvm-21 template (Temurin JDK 21) with server.port read from PORT.

## Infrastructure requirements

- **Compute**: 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**: 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 Spring Boot project (`./mvnw -q -DskipTests package` or the Gradle wrapper) producing one application jar, then `java -jar` on the jvm-21 template (Temurin JDK 21) with server.port read from PORT)
- A PostgreSQL driver reading DATABASE_URL at runtime
- An Ample account token with servers:write, databases:read

## Exact tested configuration

- **template**: `jvm-21`
- **runtime**: `java`
- **size**: `s-1vcpu-2gb`
- **build**: `./mvnw -q -DskipTests package`
- **start**: `java -jar $(ls target/*.jar | grep -v -- '-plain' | head -n 1)`

## Steps

1. **Build and start.** Run the appropriate command to build your project and start the server ensuring it binds to `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

- **Spring Boot pattern fixture** (tests/deploy-canaries/spring-boot-patterns): Verified database connection on Spring Boot.

## Success checks

- The app responds on its public URL (`/` on the live URL)
- Check the relational-records from the example (`/p/relational-records` on the live URL)

## Limitations

- Verified on the jvm-21 template at s-1vcpu-2gb; other sizes and Spring Boot 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 2026-09-21T02:34:39Z at revision `1d28ae0-dirty (CLI 0.1.21)`: Spring Boot pattern fixture deployed on Ample; for this guide: a managed PostgreSQL database auto-provisioned and injected as DATABASE_URL, with real queries succeeding at request time (records=ok). (expires 2027-03-20T02:34:39Z)

Last verified: 2026-09-21T02:34:39Z

## 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.