# Host product catalog with Spring Boot: relational catalog data

## Summary

Deploy a product catalog built with Spring Boot on Ample using the transactional workflows pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Spring Boot: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the product catalog-specific behavior as your application code.

## 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 Spring Boot project that builds and starts with the documented commands (./mvnw -q -DskipTests package (or the Gradle wrapper) producing one application jar, then java -jar on the jvm-21 template).
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
- 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 `./mvnw -q -DskipTests package` (or the Gradle wrapper) producing one application jar, then `java -jar` on the jvm-21 template with server.port read from PORT. The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL.** The fixture's module implements transactional workflows: an optimistic version check and an event row written in the same transaction. Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Deploy.** Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked).

```
   ample deploy . --name <app-name> --public
   ```
4. **Verify.** Fetch the live URL and the pattern self-test routes. Run your own checks. On failure read `ample logs <deployment_id> --kind build` then `--kind runtime`.

```
   ample logs <deployment_id> --kind build
   ```

## Success checks

- App responds on its public URL, expect ample canary spring boot patterns.
- Transactional-workflows self-test.

## Limitations

- Verified on the jvm-21 template at s-1vcpu-2gb with the example fixture; other sizes and Spring Boot major versions are not verified.
- The product catalog-specific behavior is application code and was not separately tested.

## Cost estimate

Estimated 10.00 USD per month.
- App server x1 `s-1vcpu-1gb`: 5.00 USD
- Managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

## Verification evidence

- Various deployment checks and outcomes are logged for reference.